Henipavirus
Encyclopedia
Henipavirus is a genus
of the family
Paramyxoviridae, order
Mononegavirales
containing two established species, Hendra virus and Nipah virus. The henipaviruses are naturally harboured by Pteropid
fruit bat
s (flying foxes), and some microbat species. Henipavirus is characterised by a large genome
, a wide host range, and their recent emergence as zoonotic
pathogens capable of causing illness and death in domestic animals and human
s.
In 2009, RNA sequences of three novel viruses in phylogenetic relationship to known Henipaviruses were detected in Eidolon helvum (the African Straw-coloured fruit bat) in Ghana. The finding of these novel putative Henipaviruses outside Australia and Asia indicates that the region of potential endemicity of Henipaviruses extends to Africa.
Henipaviruses are pleomorphic (variably shaped), ranging in size from 40 to 600 nm in diameter. They possess a lipid
membrane overlying a shell of viral matrix protein
. At the core is a single helical strand of genomic RNA
tightly bound to N (nucleocapsid) protein and associated with the L (large) and P (phosphoprotein) proteins which provide RNA polymerase
activity during replication.
Embedded within the lipid membrane are spikes of F (fusion) protein trimers and G (attachment) protein tetramers. The function of the G protein is to attach the virus to the surface of a host cell via EFNB2
, a highly conserved protein present in many mammals. The F protein fuses the viral membrane with the host cell membrane, releasing the virion contents into the cell. It also causes infected cells to fuse with neighbouring cells to form large, multinucleated syncytia.
RNA. Both genomes are 18.2 kb in size and contain six gene
s corresponding to six structural proteins.
In common with other members of the Paramyxovirinae subfamily, the number of nucleotide
s in the henipavirus genome is a multiple of six, consistent with what is known as the 'rule of six'. Deviation from the rule of six, through mutation or incomplete genome synthesis, leads to inefficient viral replication, probably due to structural constraints imposed by the binding between the RNA and the N protein.
Henipaviruses employ an unusual process called RNA editing
to generate multiple proteins from a single gene. The specific process in henipaviruses involves the insertion of extra guanosine
residues into the P gene mRNA prior to translation
. The number of residues added determines whether the P, V or W proteins are synthesised. The functions of the V and W proteins are unknown, but they may be involved in disrupting host antiviral mechanisms.
) was discovered in September 1994 when it caused the deaths of thirteen horse
s, and a trainer at a training complex in Hendra
, a suburb of Brisbane
in Queensland
, Australia
.
The index case, a mare, was housed with 19 other horses after falling ill, and died two days later. Subsequently, all of the horses became ill, with 13 dying. The remaining 6 animals were subsequently euthanised as a way of preventing relapsing infection and possible further transmission. Both the trainer, Victory ('Vic') Rail, and a stable hand were involved in nursing the index case and both fell ill within one week of the horse’s death with an influenza-like illness. The stable hand recovered while Mr Rail died of respiratory and renal failure. The source of the virus was most likely frothy nasal discharge from the index case.
A second outbreak
occurred in August 1994 (chronologically preceding the first outbreak) in Mackay
1,000 km north of Brisbane resulting in the deaths of two horses and their owner. The owner, Mark Preston, assisted in necropsies of the horses and within three weeks was admitted to hospital suffering from meningitis
. Mr Preston recovered, but 14 months later developed neurologic signs and died. This outbreak was diagnosed retrospectively by the presence of Hendra virus in the brain of the patient.
A survey of wildlife in the outbreak areas was conducted, and identified pteropid fruit bats as the most likely source of Hendra virus, with a seroprevalence
of 47%. All of the other 46 species sampled were negative. Virus isolations from the reproductive tract and urine of wild bats indicated that transmission to horses may have occurred via exposure to bat urine or birthing fluids.
Four of these outbreaks have spread to humans as a result of direct contact with infected horses. On 26 July 2011 a dog living on the Mt Alford property was reported to have HeV antibodies, the first time an animal other than a flying fox, horse, or human has tested positive outside an experimental situation.
These events have all been on the east coast of Australia, with the most northern event at Cairns, Queensland and the event furthest south at Macksville, NSW. Until the event at Chinchilla, Queensland in July 2011, all outbreak sites had been within the distribution of at least two of the four mainland flying-foxes (fruit bats); Little red flying-fox
, (Pteropus scapulatus), black flying-fox, (Pteropus alecto), grey-headed flying-fox
, (Pteropus poliocephalus) and spectacled flying-fox, (Pteropus conspicillatus). Chinchilla is considered to be only within the range of little red flying-fox and is west of the Great Dividing Range
. This is the furthest west the infection has ever been identified in horses.
The timing of incidents indicates a seasonal pattern of outbreaks, possibly related to the breeding cycle of the little red flying-foxes. These species typically give birth between April and May. As there is no evidence of transmission to humans directly from bats, it is thought that human infection only occurs via an intermediate host, a horse.
It's not clear why there has been a sudden increase in the number of spillover events between June and August 2011. Typically HeV spillover events are more common between May and October. This time is sometimes called "Hendra Season". This is a time when there are large numbers of fruit bats of all species congregated in SE Queensland as this area contains valuable winter foraging habitat. The weather (warm and humid) is favourable to the survival of henipavirus in the environment.
There have been suggestions that the flooding that affected SE Queensland and Northern NSW in December 2010 and January 2011 may be having an impact upon the health of the fruit bats. Urine sampling in flying-fox camps indicate that a larger proportion of flying-foxes than usual are shedding live virus. Biosecurity Queensland's ongoing surveillance usually shows 7% of the animals are shedding live virus. In June and July nearly 30% animals have been reported to be shedding live virus. Present advice is that these events are not being driven by any mutation in HeV itself.
Other suggestions include that an increase in testing has led to an increase in detection. As the actual mode of transmission between bats and horses has not been determined, it is not clear what, if any, factors can increase the chance of infection in horses.
Following the confirmation of a dog with HeV antibodies, on 27 July 2011, the Queensland and NSW governments
will boost research funding into the Hendra virus by $6 million to be spent by 2014/2015. This money will be used for research into ecological drivers of infection in the bats and the mechanism of virus transmission between bats and other species. A further 6 million dollars was allocated by the federal government with the funds being split, half for human health investigations and half for animal health and biodiversity research.
Hendra virus is in development and is expected to be available in 2013. It is composed of a soluble version of the G surface antigen on Hendra virus and has been successful in ferret models. The trial vaccine may be available in 2012.
The vaccine is intended to be used in horses as stopping the virus at this point should protect both horses and humans.
of the lungs, or encephalitic
, resulting in meningitis
. In horses, infection usually causes pulmonary oedema, congestion and / or neurological signs.
Ephrin B2 has been identified as the main receptor for the heniparviruses.
Nipah virus was identified in April 1999, when it caused an outbreak of neurological and respiratory disease on pig farms in peninsular Malaysia, resulting in 257 human cases, including 105 human deaths and the culling of one million pigs. In Singapore
, 11 cases, including one death, occurred in abattoir workers exposed to pigs imported from the affected Malaysian farms. The Nipah virus has been classified by the Centers for Disease Control and Prevention
as a Category C agent. The name "Nipah" is taken after the place, Kampung Nipah in Negeri Sembilan
, Malaysia, the source of the human case from which Nipah virus was first isolated.
The outbreak was originally mistaken for Japanese encephalitis
(JE), however, physicians in the area noted that persons who had been vaccinated against JE were not protected, and the number of cases among adults was unusual Despite the fact that these observations were recorded in the first month of the outbreak, the Ministry of Health failed to react accordingly, and instead launched a nationwide campaign to educate people on the dangers of JE and its vector, Culex
mosquitoes.
Symptoms of infection from the Malaysian outbreak were primarily encephalitic in humans and respiratory in pigs. Later outbreaks have caused respiratory illness in humans, increasing the likelihood of human-to-human transmission and indicating the existence of more dangerous strains of the virus.
Based on seroprevalence data and virus isolations, the primary reservoir for Nipah virus was identified as Pteropid fruit bats, including Pteropus vampyrus (Large Flying Fox
), and Pteropus hypomelanus (Small Flying-fox
), both of which occur in Malaysia.
The transmission of Nipah virus from flying foxes to pigs is thought to be due to an increasing overlap between bat habitats and piggeries in peninsular Malaysia. At the index farm, fruit orchards were in close proximity to the piggery, allowing the spillage of urine, faeces and partially eaten fruit onto the pigs. Retrospective studies demonstrate that viral spillover into pigs may have been occurring in Malaysia since 1996 without detection. During 1998, viral spread was aided by the transfer of infected pigs to other farms, where new outbreaks occurred.
Eight more outbreaks of Nipah virus have occurred since 1998, all within Bangladesh
and neighbouring parts of India
. The outbreak sites lie within the range of Pteropus species (Pteropus giganteus). As with Hendra virus, the timing of the outbreaks indicates a seasonal effect. Cases occurring in Bangladesh during the winters of 2001, 2003, and 2004, were determined to have been caused by the Nipah virus. In February, 2011, a Nipah outbreak began at Hatibandha Upazila
in the Lalmonirhat district
of northern Bangladesh. To date (7 February 2011), there have been 24 cases and 17 deaths in this outbreak.
Nipah virus has been isolated from Lyle's flying fox (Pteropus lylei) in Cambodia
and viral RNA found in urine and saliva from P. lylei and Horsfield's roundleaf bat (Hipposideros larvatus) in Thailand
. Infective virus has also been isolated from environmental samples of bat urine and partially-eaten fruit in Malaysia. Antibodies
to henipaviruses have also been found in fruit bats in Madagascar
(Pteropus rufus, Eidolon dupreanum) and Ghana
(Eidolon helvum) indicating a wide geographic distribution of the viruses. No infection of humans or other species have been observed in Cambodia, Thailand or Africa thus far.
Nipah virus is also known to cause relapse encephalitis. In the initial Malaysian outbreak, a patient presented with relapse encephalitis some 53 months after his initial infection. There is no definitive treatment for Nipah encephalitis, apart from supportive measures, such as mechanical ventilation and prevention of secondary infection. Ribavirin
, an antiviral drug, was tested in the Malaysian outbreak, and the results were encouraging, though further studies are still needed.
In animals, especially in pigs, the virus causes a porcine respiratory and neurologic syndrome, locally known as "barking pig syndrome" or "one mile cough."
.
viruses in recent decades. SARS coronavirus
, Australian bat lyssavirus
, Menangle virus
and probably Ebola virus
and Marburg virus
are also harbored by bats and are capable of infecting a variety of other species. The emergence of each of these viruses has been linked to an increase in contact between bats and humans, sometimes involving an intermediate domestic animal host. The increased contact is driven both by human encroachment into the bats’ territory (in the case of Nipah, specifically pigpens in said territory) and by movement of bats towards human populations due to changes in food distribution and loss of habitat.
There is evidence that habitat loss for flying-foxes, both in South Asia and Australia (particularly along the east coast) as well as encroachment of human dwellings and agriculture into the remaining habitats, is creating greater overlap of human and flying fox distributions.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Paramyxoviridae, order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Mononegavirales
Mononegavirales
The order Mononegavirales is the taxonomic home of numerous related viruses. Members of the order that are commonly known are, for instance, Ebola virus, human respiratory syncytial virus, measles virus, mumps virus, Nipah virus, and rabies virus. All of these viruses cause significant disease in...
containing two established species, Hendra virus and Nipah virus. The henipaviruses are naturally harboured by Pteropid
Pteropus
Bats of the genus Pteropus, belonging to the megabat or Megachiroptera sub-order, are the largest bats in the world. They are commonly known as the fruit bats or flying foxes among other colloquial names...
fruit bat
Fruit Bat
Fruit Bat can refer to:* Megabats, a species of bat which eats fruit* Les "Fruitbat" Carter, guitarist of Carter the Unstoppable Sex Machine* Fruit Bats , an American band...
s (flying foxes), and some microbat species. Henipavirus is characterised by a large genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
, a wide host range, and their recent emergence as zoonotic
Zoonosis
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...
pathogens capable of causing illness and death in domestic animals and human
Human
Humans are the only living species in the Homo genus...
s.
In 2009, RNA sequences of three novel viruses in phylogenetic relationship to known Henipaviruses were detected in Eidolon helvum (the African Straw-coloured fruit bat) in Ghana. The finding of these novel putative Henipaviruses outside Australia and Asia indicates that the region of potential endemicity of Henipaviruses extends to Africa.
Virus structure
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
membrane overlying a shell of viral matrix protein
Matrix protein
Viral matrix proteins are non structural proteins linking the viral envelope with the virus core. They play a crucial role in virus assembly, and interact with the RNP complex as well as with the viral membrane...
. At the core is a single helical strand of genomic RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
tightly bound to N (nucleocapsid) protein and associated with the L (large) and P (phosphoprotein) proteins which provide RNA polymerase
RNA polymerase
RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
activity during replication.
Embedded within the lipid membrane are spikes of F (fusion) protein trimers and G (attachment) protein tetramers. The function of the G protein is to attach the virus to the surface of a host cell via EFNB2
EFNB2
Ephrin-B2 is a protein that in humans is encoded by the EFNB2 gene.-Further reading:...
, a highly conserved protein present in many mammals. The F protein fuses the viral membrane with the host cell membrane, releasing the virion contents into the cell. It also causes infected cells to fuse with neighbouring cells to form large, multinucleated syncytia.
Genome structure
As with all viruses in the Mononegavirales order, the Hendra virus and Nipah virus genomes are non-segmented, single-stranded negative-senseSense (molecular biology)
In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
RNA. Both genomes are 18.2 kb in size and contain six gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s corresponding to six structural proteins.
In common with other members of the Paramyxovirinae subfamily, the number of nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
s in the henipavirus genome is a multiple of six, consistent with what is known as the 'rule of six'. Deviation from the rule of six, through mutation or incomplete genome synthesis, leads to inefficient viral replication, probably due to structural constraints imposed by the binding between the RNA and the N protein.
Henipaviruses employ an unusual process called RNA editing
RNA editing
The term RNA editing describes those molecular processes in which the information content in an RNA molecule is altered through a chemical change in the base makeup. To date, such changes have been observed in tRNA, rRNA, mRNA and microRNA molecules of eukaryotes but not prokaryotes...
to generate multiple proteins from a single gene. The specific process in henipaviruses involves the insertion of extra guanosine
Guanosine
Guanosine is a purine nucleoside comprising guanine attached to a ribose ring via a β-N9-glycosidic bond. Guanosine can be phosphorylated to become guanosine monophosphate , cyclic guanosine monophosphate , guanosine diphosphate , and guanosine triphosphate...
residues into the P gene mRNA prior to translation
Translation (genetics)
In molecular biology and genetics, translation is the third stage of protein biosynthesis . In translation, messenger RNA produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein...
. The number of residues added determines whether the P, V or W proteins are synthesised. The functions of the V and W proteins are unknown, but they may be involved in disrupting host antiviral mechanisms.
Emergence
Hendra virus (originally Equine morbillivirusMorbillivirus
Morbillivirus is a genus belonging to the Paramyxoviridae family of viruses in the order Mononegavirales. Many members of the genus cause diseases, such as rinderpest and measles, and are highly infectious.- External links :* *...
) was discovered in September 1994 when it caused the deaths of thirteen horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s, and a trainer at a training complex in Hendra
Hendra, Queensland
Hendra is a suburb of the city of Brisbane, Queensland, Australia. It lies roughly six kilometres north-east of Brisbane central business district.- History :...
, a suburb of Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
in Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
The index case, a mare, was housed with 19 other horses after falling ill, and died two days later. Subsequently, all of the horses became ill, with 13 dying. The remaining 6 animals were subsequently euthanised as a way of preventing relapsing infection and possible further transmission. Both the trainer, Victory ('Vic') Rail, and a stable hand were involved in nursing the index case and both fell ill within one week of the horse’s death with an influenza-like illness. The stable hand recovered while Mr Rail died of respiratory and renal failure. The source of the virus was most likely frothy nasal discharge from the index case.
A second outbreak
Outbreak
Outbreak is a term used in epidemiology to describe an occurrence of disease greater than would otherwise be expected at a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Two linked cases of a rare infectious...
occurred in August 1994 (chronologically preceding the first outbreak) in Mackay
Mackay, Queensland
Mackay is a city on the eastern coast of Queensland, Australia, about north of Brisbane, on the Pioneer River. Mackay is nicknamed the sugar capital of Australia because its region produces more than a third of Australia's cane sugar....
1,000 km north of Brisbane resulting in the deaths of two horses and their owner. The owner, Mark Preston, assisted in necropsies of the horses and within three weeks was admitted to hospital suffering from meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
. Mr Preston recovered, but 14 months later developed neurologic signs and died. This outbreak was diagnosed retrospectively by the presence of Hendra virus in the brain of the patient.
A survey of wildlife in the outbreak areas was conducted, and identified pteropid fruit bats as the most likely source of Hendra virus, with a seroprevalence
Seroprevalence
Seroprevalence is the number of persons in a population who test positive for a specific disease based on serology specimens; often presented as a percent of the total specimens tested or as a proportion per 100,000 persons tested...
of 47%. All of the other 46 species sampled were negative. Virus isolations from the reproductive tract and urine of wild bats indicated that transmission to horses may have occurred via exposure to bat urine or birthing fluids.
Australian outbreaks
As of 11 October 2011, a total of thirty-two events of Hendra virus have occurred, all involving infection of horses. As a result of these events, sixty-eight horses have died or been euthanised, with a further four having died or been euthanised as a result of possibly hendra infection.Four of these outbreaks have spread to humans as a result of direct contact with infected horses. On 26 July 2011 a dog living on the Mt Alford property was reported to have HeV antibodies, the first time an animal other than a flying fox, horse, or human has tested positive outside an experimental situation.
These events have all been on the east coast of Australia, with the most northern event at Cairns, Queensland and the event furthest south at Macksville, NSW. Until the event at Chinchilla, Queensland in July 2011, all outbreak sites had been within the distribution of at least two of the four mainland flying-foxes (fruit bats); Little red flying-fox
Little Red Flying-fox
The Little Red Flying Fox is a species of megabat native to northern and eastern Australia. With a weight of it is large fruit bat, but the smallest Flying Fox in mainland Australia . It has the widest range of all the species, going much further inland than the larger fruit bats...
, (Pteropus scapulatus), black flying-fox, (Pteropus alecto), grey-headed flying-fox
Grey-headed Flying Fox
The Grey-headed Flying-Fox, Pteropus poliocephalus, is a megabat native to Australia.Members of the genus Pteropus include the largest bats in the world. The Pteropus genus has currently about 57 recognised species....
, (Pteropus poliocephalus) and spectacled flying-fox, (Pteropus conspicillatus). Chinchilla is considered to be only within the range of little red flying-fox and is west of the Great Dividing Range
Great Dividing Range
The Great Dividing Range, or the Eastern Highlands, is Australia's most substantial mountain range and the third longest in the world. The range stretches more than 3,500 km from Dauan Island off the northeastern tip of Queensland, running the entire length of the eastern coastline through...
. This is the furthest west the infection has ever been identified in horses.
The timing of incidents indicates a seasonal pattern of outbreaks, possibly related to the breeding cycle of the little red flying-foxes. These species typically give birth between April and May. As there is no evidence of transmission to humans directly from bats, it is thought that human infection only occurs via an intermediate host, a horse.
- August 1994, MackayMackay, QueenslandMackay is a city on the eastern coast of Queensland, Australia, about north of Brisbane, on the Pioneer River. Mackay is nicknamed the sugar capital of Australia because its region produces more than a third of Australia's cane sugar....
, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of two horses and one person, Mark Preston. - September 1994, Hendra, QueenslandHendra, QueenslandHendra is a suburb of the city of Brisbane, Queensland, Australia. It lies roughly six kilometres north-east of Brisbane central business district.- History :...
: 20 horses died or were euthanised. Two people infected, with one death, Victor Rail who was a nationally prominent trainer of racing horses. - January 1999, Trinity Beach, Cairns, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - October 2004, Gordonvale, Cairns, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. A veterinarian involved in autopsy of the horse was infected with Hendra virus, and suffered a mild illness. - December 2004, Townsville, QueenslandTownsville, QueenslandTownsville is a city on the north-eastern coast of Australia, in the state of Queensland. Adjacent to the central section of the Great Barrier Reef, it is in the dry tropics region of Queensland. Townsville is Australia's largest urban centre north of the Sunshine Coast, with a 2006 census...
: Death of one horse. - June 2006, Peachester, Sunshine Coast, QueenslandSunshine Coast, QueenslandThe Sunshine Coast is an urban area in South East Queensland, north of the state capital of Brisbane on the Pacific Ocean coastline. Although it does not have a central business district, by population it ranks as the 10th largest metropolis in Australia and the third largest in...
: Death of one horse. - October 2006, Murwillumbah, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
: Death of one horse. - July 2007, Peachester, Sunshine Coast, QueenslandSunshine Coast, QueenslandThe Sunshine Coast is an urban area in South East Queensland, north of the state capital of Brisbane on the Pacific Ocean coastline. Although it does not have a central business district, by population it ranks as the 10th largest metropolis in Australia and the third largest in...
: Infection of one horse (euthanised) - July 2007, Clifton BeachClifton Beach, QueenslandClifton Beach is a dormitory suburb of Cairns, Queensland, Australia located on the shores of the Coral Sea.- External links :*...
, Cairns, Queensland: Infection of one horse (euthanised). - July 2008, Redlands, BrisbaneBrisbaneBrisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of five horses; four died from the Henda virus, the remaining animal recovered but was euthanised because of a government policy that requires all animals with antibodies to be euthanised due to a potential threat to health. Two veterinary workers from the affected property were infected leading to the death of one, veterinary surgeon Ben Cuneen, on the 20th of August, 2008. The second veterinarian was hospitalized after pricking herself with a needle she had used to euthanize the horse that had recovered. A nurse exposed to the disease while assisting Cuneen in caring for the infected horses was also hospitalized. The Biosecurity Queensland website indicates that 8 horses died during this event (http://www.dpi.qld.gov.au/4790_11112.htm, access 31 July 2011) however a review of the event indicates that five horses are confirmed to have died from HeV and three of the horses "are regarded as improbable cases of Hendra virus infection ...". - July 2008, Proserpine, QueenslandProserpine, Queensland-External links:* * * * *...
; Death of four horses. - July 2009, Cawarral, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of four horses. Queensland veterinary surgeon Alister Rodgers tested positive after treating the horses. On September 1, 2009 after two weeks in a coma, he became the fourth person to die from exposure to the virus. - September 2009, BowenBowen, QueenslandBowen is a town on the eastern coast of Queensland, Australia. At the 2006 census, Bowen had a population of 7,484.-Geography:Bowen is located on the north-east coast of Australia, at exactly twenty degrees south of the equator. In fact, the twentieth parallel crosses the main street...
, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
. Death of two horses. - May 2010, Tewantin, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - 20 June 2011 - 31 July 2011, Mt Alford, (near Boonah) QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of three horses (all confirmed to have died of Hendra) and sero-conversion of a dog. The first horse death on this property occurred on 20 June 2011, although it was not until after the second death on 1 July 2011 that samples taken from the first animal were tested. The third horse was euthanised on 4 July 2011. On 26 July 2011 a dog from this property was reported to have tested positive for HeV antibodies. Reports indicate that this Australian KelpieAustralian KelpieThe Kelpie is an Australian sheep dog successful at mustering and droving with little or no command guidance. They are medium-sized dogs and come in a variety of colours...
, a family companion, will be euthanised in line with government policy. Biosecurity Queensland suggest the dog most likely was exposed to HeV though one of the sick horses. Dusty was euthanised on 31 July 2011 following a second positive antibody test. - 26 June 2011, Kerry, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
(the horse was moved after it became sick to another property at BeaudesertBeaudesert, QueenslandBeaudesert is a town located on the Mount Lindesay Highway, some 64 km south of Brisbane. It is possibly named after Beau Desert Park, the property of Charles Henry Alexander Paget, 6th Marquess of Anglesey in Staffordshire, England...
), Queensland: Death of one horse. - 28 June 2011 Loganlea, Logan City, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: death of one horse. - 29 June 2011, Mcleans Ridges, Wollongbar, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
: Death of one horse. The second horse on the property tested positive to Hendra and was euthanised on 12 July 2011. - 3 July 2011, Macksville, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
: Death of one horse. - 4 July 2011, Park RidgePark Ridge, QueenslandPark Ridge is a suburb of Logan City, Queensland, Australia. Park Ridge lies to Logan's west and enjoys a rural setting. There are manicured acreage properties buffered by pretty bushland and the suburb holds great appeal for horse lovers.-History:...
, Logan City, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - 11 July 2011, KurandaKuranda, QueenslandKuranda is a town on the Atherton Tableland in Far North Queensland, Australia, it is 25 kilometres from Cairns, via the Kuranda Range road. It is surrounded by rainforest. At the 2006 census, Kuranda had a population of 1,611.-History:...
, west of Cairns, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - 13 July 2011, Hervey Bay, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - 14 July 2011, LismoreLismore, New South WalesLismore is a subtropical town in northeastern New South Wales, Australia. Lismore is the main population centre in the City of Lismore local government area. Lismore is a regional centre in the Northern Rivers region of the State.-History:...
, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
: Death of one horse. - 15 July 2011, Boondall, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - 22 July 2011, Chinchilla, QueenslandChinchilla, QueenslandChinchilla is a town in the Darling Downs region of Queensland, Australia. At the 2006 census, Chinchilla had a population of 3,681.The town was established in 1877...
:Death of one horse. - 24 July 2011, Mullumbimby, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
: Death of one horse. - 13 August 2011, Mullumbimby, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
: Death of one horse. A horse was found dead after being unwell the day before. HeV infection was confirmed on 17 August 2011. - 15 August 2011 Ballina, New South WalesBallina, New South WalesBallina is a town on the Northern Rivers of New South Wales, Australia, and the seat of the Ballina Shire Local Government Area. It had a population of 16,477 in the 2006 Census.-Location:...
: Death of one horse. - 17 August 2011, South Ballina, New South WalesBallina, New South WalesBallina is a town on the Northern Rivers of New South Wales, Australia, and the seat of the Ballina Shire Local Government Area. It had a population of 16,477 in the 2006 Census.-Location:...
: Death of two horses. The 2 horses were found dead in a field. Both tested positive to HeV. The exact date of death is not known however HeV infection was confirmed on 17 August 2011. - 23 August 2011, Currumbin Valley, Gold CoastGold Coast, QueenslandGold Coast is a coastal city of Australia located in South East Queensland, 94km south of the state capital Brisbane. With a population approximately 540,000 in 2010, it is the second most populous city in the state, the sixth most populous city in the country, and also the most populous...
, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Death of one horse. - 28 August 2011, North of Ballina, New South WalesBallina, New South WalesBallina is a town on the Northern Rivers of New South Wales, Australia, and the seat of the Ballina Shire Local Government Area. It had a population of 16,477 in the 2006 Census.-Location:...
:Death of one horse. - 11 October 2011, Beechmere, Caboolture QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
. One horse euthanised after testing positive. A horse died one week previous on the property may have died of HeV. On 15 October 2011 another horse on the property was euthanised following a positive HeV antibody test.
Events of June – August 2011
In the years 1994–2010, fourteen events were recorded. Between 20 June 2011 and 28 August 2011, a further seventeen events were identified, during which twenty-one horses died.It's not clear why there has been a sudden increase in the number of spillover events between June and August 2011. Typically HeV spillover events are more common between May and October. This time is sometimes called "Hendra Season". This is a time when there are large numbers of fruit bats of all species congregated in SE Queensland as this area contains valuable winter foraging habitat. The weather (warm and humid) is favourable to the survival of henipavirus in the environment.
There have been suggestions that the flooding that affected SE Queensland and Northern NSW in December 2010 and January 2011 may be having an impact upon the health of the fruit bats. Urine sampling in flying-fox camps indicate that a larger proportion of flying-foxes than usual are shedding live virus. Biosecurity Queensland's ongoing surveillance usually shows 7% of the animals are shedding live virus. In June and July nearly 30% animals have been reported to be shedding live virus. Present advice is that these events are not being driven by any mutation in HeV itself.
Other suggestions include that an increase in testing has led to an increase in detection. As the actual mode of transmission between bats and horses has not been determined, it is not clear what, if any, factors can increase the chance of infection in horses.
Following the confirmation of a dog with HeV antibodies, on 27 July 2011, the Queensland and NSW governments
Government of New South Wales
The form of the Government of New South Wales is prescribed in its Constitution, which dates from 1856, although it has been amended many times since then...
will boost research funding into the Hendra virus by $6 million to be spent by 2014/2015. This money will be used for research into ecological drivers of infection in the bats and the mechanism of virus transmission between bats and other species. A further 6 million dollars was allocated by the federal government with the funds being split, half for human health investigations and half for animal health and biodiversity research.
Vaccine
A subunit vaccine that will neutraliseNeutralisation (immunology)
Neutralisation in the immunological sense refers to the ability of antibodies to block the site on bacteria or viruses that they use to enter their target cell. One example of this within biology is a neutralizing antibody....
Hendra virus is in development and is expected to be available in 2013. It is composed of a soluble version of the G surface antigen on Hendra virus and has been successful in ferret models. The trial vaccine may be available in 2012.
The vaccine is intended to be used in horses as stopping the virus at this point should protect both horses and humans.
Pathology
Flying foxes experimentally infected with the Hendra virus develop a viraemia then excrete the virus in their urine, faeces and saliva for approximately one week. Although they excrete live virus during this time there is no other indication of an illness. Symptoms of Hendra virus infection of humans may be respiratory, including hemorrhage and edemaPulmonary edema
Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...
of the lungs, or encephalitic
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
, resulting in meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
. In horses, infection usually causes pulmonary oedema, congestion and / or neurological signs.
Ephrin B2 has been identified as the main receptor for the heniparviruses.
Emergence
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
, 11 cases, including one death, occurred in abattoir workers exposed to pigs imported from the affected Malaysian farms. The Nipah virus has been classified by the Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
as a Category C agent. The name "Nipah" is taken after the place, Kampung Nipah in Negeri Sembilan
Negeri Sembilan
Negeri Sembilan, one of the 13 states that constitutes Malaysia, lies on the western coast of Peninsular Malaysia, just south of Kuala Lumpur and borders Selangor on the north, Pahang in the east, and Malacca and Johor to the south....
, Malaysia, the source of the human case from which Nipah virus was first isolated.
The outbreak was originally mistaken for Japanese encephalitis
Japanese Encephalitis
Japanese encephalitis —previously known as Japanese B encephalitis to distinguish it from von Economo's A encephalitis—is a disease caused by the mosquito-borne Japanese encephalitis virus. The Japanese encephalitis virus is a virus from the family Flaviviridae. Domestic pigs and wild birds are...
(JE), however, physicians in the area noted that persons who had been vaccinated against JE were not protected, and the number of cases among adults was unusual Despite the fact that these observations were recorded in the first month of the outbreak, the Ministry of Health failed to react accordingly, and instead launched a nationwide campaign to educate people on the dangers of JE and its vector, Culex
Culex
Culex is a genus of mosquito, and is important in that several species serve as vectors of important diseases, such as West Nile virus, filariasis, Japanese encephalitis, St. Louis encephalitis and avian malaria....
mosquitoes.
Symptoms of infection from the Malaysian outbreak were primarily encephalitic in humans and respiratory in pigs. Later outbreaks have caused respiratory illness in humans, increasing the likelihood of human-to-human transmission and indicating the existence of more dangerous strains of the virus.
Based on seroprevalence data and virus isolations, the primary reservoir for Nipah virus was identified as Pteropid fruit bats, including Pteropus vampyrus (Large Flying Fox
Large Flying Fox
The Large Flying Fox , also known as the Greater Flying Fox, Malaysian Flying Fox, Kalang or Kalong, is a species of megabat in the family Pteropodidae. Like the other members of the genus Pteropus, or the Old World fruit bats, it feeds exclusively on fruits. It is noted for being the largest...
), and Pteropus hypomelanus (Small Flying-fox
Small Flying-fox
The Small Flying Fox or Variable Flying Fox is a species of megabat in the Pteropodidae family. It is found in Australia, Cambodia, Indonesia, Malaysia, Maldives, Myanmar, Papua New Guinea, the Philippines, the Solomon Islands, Thailand, and Vietnam.-References:* Chiroptera Specialist Group 1996....
), both of which occur in Malaysia.
The transmission of Nipah virus from flying foxes to pigs is thought to be due to an increasing overlap between bat habitats and piggeries in peninsular Malaysia. At the index farm, fruit orchards were in close proximity to the piggery, allowing the spillage of urine, faeces and partially eaten fruit onto the pigs. Retrospective studies demonstrate that viral spillover into pigs may have been occurring in Malaysia since 1996 without detection. During 1998, viral spread was aided by the transfer of infected pigs to other farms, where new outbreaks occurred.
Outbreaks
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
and neighbouring parts of India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. The outbreak sites lie within the range of Pteropus species (Pteropus giganteus). As with Hendra virus, the timing of the outbreaks indicates a seasonal effect. Cases occurring in Bangladesh during the winters of 2001, 2003, and 2004, were determined to have been caused by the Nipah virus. In February, 2011, a Nipah outbreak began at Hatibandha Upazila
Hatibandha Upazila
Hatibandha is an Upazila of Lalmonirhat District in the Division of Rajshahi, Bangladesh.-Geography:Hatibandha is located at . It has 33369 units of house hold and total area 288.42 km².-Demographics:...
in the Lalmonirhat district
Lalmonirhat District
The district of Lalmonirhat consists 3038 mosques, 512 temples, 43 Buddhist temples and 12 churches.-Tourism:There are a number of tourist attractions and archaeological sites in Lalmonirhat...
of northern Bangladesh. To date (7 February 2011), there have been 24 cases and 17 deaths in this outbreak.
- 2001 January 31 – February 23, SiliguriSiliguriSiliguri is a city in the Indian state of West Bengal. It is located in the Siliguri Corridor or Chicken's Neck - a very narrow strip of land linking mainland India to its north-eastern states. It is also the transit point for air, road and rail traffic to the neighbouring countries of Nepal,...
, India: 66 cases with a 74% mortality rate. 75% of patients were either hospital staff or had visited one of the other patients in hospital, indicating person-to-person transmission. - 2001 April – May, Meherpur district, Bangladesh: 13 cases with nine fatalities (69% mortality).
- 2003 January, Naogaon district, Bangladesh: 12 cases with eight fatalities (67% mortality).
- 2004 January – February, Manikganj and Rajbari provinces, Bangladesh: 42 cases with 14 fatalities (33% mortality).
- 2004 19 February – 16 April, Faridpur districtFaridpur DistrictFaridpur is a district in central Bangladesh. It is a part of the Dhaka Division. Faridpur District has a population of over 1.7 million people and is situated on the banks of the Padma river . It is bordered by Madaripur, Narail, Rajbari, Magura, Shariatpur, Gopalgonj, Dhaka and Manikganj...
, Bangladesh: 36 cases with 27 fatalities (75% mortality). Epidemiological evidence strongly suggests that this outbreak involved person-to-person transmission of Nipah virus, which had not previously been confirmed. 92% of cases involved close contact with at least one other person infected with Nipah virus. Two cases involved a single short exposure to an ill patient, including a rickshaw driver who transported a patient to hospital. In addition, at least six cases involved acute respiratory distress syndrome which has not been reported previously for Nipah virus illness in humans. This symptom is likely to have assisted human-to-human transmission through large droplet dispersal. - 2005 January, TangailTangailTangail is a town in Tangail District located in central region of Bangladesh. It consists of 5 corporations, 8 municipalities, 72 wards, 211 mahallas. It is located on the banks of Louhajang River, and is part of the Dhaka Division.-Education:...
district, Bangladesh: 12 cases with 11 fatalities (92% mortality). The virus was probably contracted from drinking date palm juice contaminated by fruit bat droppings or saliva. - 2007 February – May, Nadia DistrictNadia DistrictNadia district is a district of the state of West Bengal, in the north east of India. It borders with Bangladesh to the east, North 24 Parganas and Hooghly districts to the south, Bardhaman district to the west, and Murshidabad district to the north....
, India: up to 50 suspected cases with 3-5 fatalities. The outbreak site borders the Bangladesh district of Kushtia where eight cases of Nipah virus encephalitis with five fatalities occurred during March and April 2007. This was preceded by an outbreak in Thakurgaon during January and February affecting seven people with three deaths. All three outbreaks showed evidence of person-to-person transmission. - 2008 February - March, Manikganj and Rajbari provinces, Bangladesh: Nine cases with eight fatalities.
- 2010 January, Bhanga subdistrict, Faridpur, Bangladesh: Eight cases with seven fatalities. During March, one physician of Faridpur Medical College Hospital caring for confirmed Nipah cases died
- 2011 February: An outbreak of Nipah Virus has occurred at Hatibandha, Lalmonirhat, Bangladesh. The deaths of 21 schoolchildren due to Nipah virus infection were recorded on 4 February 2011. IEDCR has confirmed the infection is due to this virus. Local schools were closed for one week to prevent the spread of the virus. People were also requested to avoid consumption of uncooked fruits and fruit products. Such foods, contaminated with urine or saliva from infected fruit bats, were the most likely source of this outbreak.
Nipah virus has been isolated from Lyle's flying fox (Pteropus lylei) in Cambodia
Cambodia
Cambodia , officially known as the Kingdom of Cambodia, is a country located in the southern portion of the Indochina Peninsula in Southeast Asia...
and viral RNA found in urine and saliva from P. lylei and Horsfield's roundleaf bat (Hipposideros larvatus) in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
. Infective virus has also been isolated from environmental samples of bat urine and partially-eaten fruit in Malaysia. Antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
to henipaviruses have also been found in fruit bats in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
(Pteropus rufus, Eidolon dupreanum) and Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...
(Eidolon helvum) indicating a wide geographic distribution of the viruses. No infection of humans or other species have been observed in Cambodia, Thailand or Africa thus far.
Pathology
In humans, the infection presents as fever, headache and drowsiness. Cough, abdominal pain, nausea, vomiting, weakness, problems with swallowing and blurred vision are relatively common. About a quarter of the patients have seizures and about 60% become comatose and might need mechanical ventilation. In patients with severe disease, their conscious state may deteriorate and they may develop severe hypertension, fast heart rate, and very high temperature.Nipah virus is also known to cause relapse encephalitis. In the initial Malaysian outbreak, a patient presented with relapse encephalitis some 53 months after his initial infection. There is no definitive treatment for Nipah encephalitis, apart from supportive measures, such as mechanical ventilation and prevention of secondary infection. Ribavirin
Ribavirin
Ribavirin is an anti-viral drug indicated for severe RSV infection , hepatitis C infection and other viral infections. Ribavirin is a prodrug, which when metabolised resembles purine RNA nucleotides...
, an antiviral drug, was tested in the Malaysian outbreak, and the results were encouraging, though further studies are still needed.
In animals, especially in pigs, the virus causes a porcine respiratory and neurologic syndrome, locally known as "barking pig syndrome" or "one mile cough."
In popular culture
Nipah virus was the inspiration for the MEV-1 virus in the film ContagionContagion (film)
Contagion is a 2011 American medical thriller disaster film directed by Steven Soderbergh. The film has an ensemble cast that includes Marion Cotillard, Matt Damon, Laurence Fishburne, Jude Law, Gwyneth Paltrow, Kate Winslet, and Bryan Cranston. Contagion follows the rapid progress of a lethal...
.
Causes of emergence
The emergence of henipaviruses parallels the emergence of other zoonoticZoonosis
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...
viruses in recent decades. SARS coronavirus
SARS coronavirus
The SARS coronavirus, sometimes shortened to SARS-CoV, is the virus that causes severe acute respiratory syndrome . On April 16, 2003, following the outbreak of SARS in Asia and secondary cases elsewhere in the world, the World Health Organization issued a press release stating that the...
, Australian bat lyssavirus
Australian bat lyssavirus
Australian bat lyssavirus is a zoonotic virus closely related to rabies virus. It was first identified in a 5-month old juvenile Black Flying Fox collected near Ballina in northern New South Wales, Australia in 1996 during a national surveillance program for the recently identified Hendra virus...
, Menangle virus
Menangle virus
Menangle virus is a virus that infects pigs, humans and bats.-History:Menangle virus was first identified in 1997 after a piggery in Menangle near Sydney, NSW, Australia experienced a high number of stillbirths and deformities during farrowing. Two workers at the piggery came down with an...
and probably Ebola virus
Ebola virus
Ebola virus causes severe disease in humans and in nonhuman primates in the form of viral hemorrhagic fever. EBOV is a Select Agent, World Health Organization Risk Group 4 Pathogen , National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogen,...
and Marburg virus
Marburg virus
Marburg virus disease is the name for the human disease caused by any of the two marburgviruses Marburg virus and Ravn virus...
are also harbored by bats and are capable of infecting a variety of other species. The emergence of each of these viruses has been linked to an increase in contact between bats and humans, sometimes involving an intermediate domestic animal host. The increased contact is driven both by human encroachment into the bats’ territory (in the case of Nipah, specifically pigpens in said territory) and by movement of bats towards human populations due to changes in food distribution and loss of habitat.
There is evidence that habitat loss for flying-foxes, both in South Asia and Australia (particularly along the east coast) as well as encroachment of human dwellings and agriculture into the remaining habitats, is creating greater overlap of human and flying fox distributions.
External links
- Personal Protective Equipment for dealing with infected horses
- Biosecurity Queensland Hendra virus
- Hendra virus information with links to authoritative sources
- ViralZone: Henipavirus
- Hendra virus CSIRO FAQ
- Nipah virus CSIRO FAQ
- Henipavirus Henipavirus Ecology Research Group (HERG) INFO
- Animal viruses
- Virus Pathogen Database and Analysis Resource (ViPR): Paramyxoviridae