EV-71
Encyclopedia
Enterovirus
71 (EV71) is a virus of the Enterovirudae family notable for its etiological role in epidemics of severe neurological diseases in children. It is first isolated and characterized from cases of neurological disease in California
in 1969.
(HFMD). However, EV71 also has the potential to cause severe neurological disease. To date, little is known about the molecular mechanisms of host response to EV71 infection. [...] EV71 infection led to increases in the level of mRNAs encoding chemokines, proteins involved in protein degradation, complement proteins, and proapoptotis proteins."
"Enterovirus 71 (EV71), one of the major causative agents for hand, foot and mouth disease (HFMD), is sometimes associated with severe central nervous system diseases. In 1997, in Malaysia and Japan, and in 1998 in Taiwan, there were HFMD epidemics involving sudden deaths among young children, and EV71 was isolated from the HFMD patients, including the fatal cases. The nucleotide sequences of each EV71 isolate were determined and compared by phylogenetical analysis. EV71 strains from previously reported epidemics belonged to genotype A-1, while those from recent epidemics could be divided into two genotypes, A-2 and B."
"Ever since the 1980s, large and small EV71 epidemic
s caused by distinct genotypes have occurred in Asia
n countries and regions sharing trade with China
. In Hong Kong
, sporadic EV71 infections with incidences of monoplegia
were reported in 1987, and a fatal case was documented in 2001. A large outbreak of HFMD due to EV71 infection occurred in Taiwan in 1998, including 129,106 case reports, 405 children with severe complications, and more than 80 deaths. After 1998, smaller EV71 epidemics occurred almost annually in Taiwan, primarily associated with EV71 viruses of genotypes C2 and B4. In Malaysia, EV71 outbreaks occurred in 1997 and 2000, mainly associated with genotypes B3 and B4. Since 1997, EV71 epidemics (genotypes B and C) have been reported annually in Singapore, with genotype B4 forming the predominant causative agent of a large outbreak in 2000 (5). In Korea, an EV71 epidemic in 2000 was caused by a relatively new genotype, C3, which has only rarely been identified outside of Korea in recent years (10). Thus, the EV71 genotypes of these HFMD epidemics seem to be regionally and temporally unrestricted."
or antiviral
agent known to be effective in treating or preventing EV71 infection. Experimental vaccines and antiviral agents are being worked on. For example, "both bovine and human lactoferrin
s were found to be potent inhibitors of EV71 infection" and "ribavirin
could be a potential anti-EV71 drug."
Enteroviruses were isolated from a total of 1,892 patients in this laboratory during this period. Of the virus
isolates, enterovirus 71 (EV71) was diagnosed in 44.4% of the patients (132 of 297) in 1998, 2% (13 of 646) in
1999, and 20.5% (195 of 949) in 2000. Genetic analyses of the 5�-untranslated and VP1 regions of EV71 isolates
by reverse transcription-PCR and sequencing were performed to understand the diversity of EV71 in these
outbreaks of HFMD. Most EV71 isolates from the 1998 epidemic belonged to genotype C, while only one-tenth
of the isolates were genotype B. Interestingly, all EV71 isolates tested from 1999 to 2000 belonged to genotype
B. This study indicated that two genogroups of EV71 capable of inducing severe clinical illness have been
circulating in Taiwan. Furthermore, the predominant EV71 genotypes responsible for each of the two major
HFMD outbreaks within the 3-year period in Taiwan were different."
, People's Republic of China
, but each year there were small, local outbreaks associated with only a few cases of neurological disease and no reported fatalities. Genetic analysis revealed 19 cases of EV71 among 147 children who had hand, foot, and mouth disease in Shenzhen
during this time.
Until 2008, no large EV71 epidemic had been reported on the Chinese mainland, but sporadic infections were common in the southeast coastal area as well as inland regions, such as Beijing, Chongqing, and Jinan. From 1998 to 2004, the only EV71 viruses identified on mainland China belonged to the genotype C4, indicating far less variety in China than in Taiwan
.
On May 3, 2008, Chinese health authorities reported a major outbreak of EV71 enterovirus in Fuyang city and other localities in Anhui, Zhejiang, and Guangdong provinces. As of May 3, 2008, 3736 cases occurring mainly in children have been reported, with 22 dead and 42 critically ill. Some 415 new cases have been reported in the last 24 hours in Fuyang City alone. As of May 5, 2008, 6,300 were sickened by the viral outbreak which killed another child, in Zhejiang
raising the death toll to 26 children, with 1,198 other children affected in that province alone. Specifically, an additional 5,151 cases were reported in Anhui
province with scores more in 4 other provinces. 8,531 cases of children infected with hand-foot-mouth disease (HFMD) were reported in China. All the children infected are aged below 6, with most of them being under 2. As of May 7 contagious HFMD led to 28 deaths. Xinhua reported the number of people infected, also rose by 4000 to 15,799.
Enterovirus
Enteroviruses are a genus of ssRNA viruses associated with several human and mammalian diseases. Serologic studies have distinguished 66 human enterovirus serotypes on the basis of antibody neutralization tests. Additional antigenic variants have been defined within several of the serotypes on the...
71 (EV71) is a virus of the Enterovirudae family notable for its etiological role in epidemics of severe neurological diseases in children. It is first isolated and characterized from cases of neurological disease in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in 1969.
Pathology
The Enterovirus 71 (EV71) infection may be asymptomatic or may cause diarrhea, rashes, and hand, foot and mouth diseaseHand, foot and mouth disease
Hand, foot and mouth disease is a human syndrome caused by intestinal viruses of the Picornaviridae family. The most common strains causing HFMD are Coxsackie A virus and Enterovirus 71 ....
(HFMD). However, EV71 also has the potential to cause severe neurological disease. To date, little is known about the molecular mechanisms of host response to EV71 infection. [...] EV71 infection led to increases in the level of mRNAs encoding chemokines, proteins involved in protein degradation, complement proteins, and proapoptotis proteins."
"Enterovirus 71 (EV71), one of the major causative agents for hand, foot and mouth disease (HFMD), is sometimes associated with severe central nervous system diseases. In 1997, in Malaysia and Japan, and in 1998 in Taiwan, there were HFMD epidemics involving sudden deaths among young children, and EV71 was isolated from the HFMD patients, including the fatal cases. The nucleotide sequences of each EV71 isolate were determined and compared by phylogenetical analysis. EV71 strains from previously reported epidemics belonged to genotype A-1, while those from recent epidemics could be divided into two genotypes, A-2 and B."
"Ever since the 1980s, large and small EV71 epidemic
Epidemic
In epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...
s caused by distinct genotypes have occurred in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n countries and regions sharing trade with China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. In Hong Kong
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
, sporadic EV71 infections with incidences of monoplegia
Monoplegia
In medicine, monoplegia is a paralysis of a single limb, usually an arm. It is frequently associated with cerebral palsy. This is the mildest form of cerebral palsy, and individuals with it generally have a good prognosis for later life. It can also be used if just one muscle group or muscle is...
were reported in 1987, and a fatal case was documented in 2001. A large outbreak of HFMD due to EV71 infection occurred in Taiwan in 1998, including 129,106 case reports, 405 children with severe complications, and more than 80 deaths. After 1998, smaller EV71 epidemics occurred almost annually in Taiwan, primarily associated with EV71 viruses of genotypes C2 and B4. In Malaysia, EV71 outbreaks occurred in 1997 and 2000, mainly associated with genotypes B3 and B4. Since 1997, EV71 epidemics (genotypes B and C) have been reported annually in Singapore, with genotype B4 forming the predominant causative agent of a large outbreak in 2000 (5). In Korea, an EV71 epidemic in 2000 was caused by a relatively new genotype, C3, which has only rarely been identified outside of Korea in recent years (10). Thus, the EV71 genotypes of these HFMD epidemics seem to be regionally and temporally unrestricted."
Treatment
There is no vaccineVaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
or antiviral
Antiviral drug
Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics for bacteria, specific antivirals are used for specific viruses...
agent known to be effective in treating or preventing EV71 infection. Experimental vaccines and antiviral agents are being worked on. For example, "both bovine and human lactoferrin
Lactoferrin
Lactoferrin , also known as lactotransferrin , is a multifunctional protein of the transferrin family. Lactoferrin is a globular glycoprotein with a molecular mass of about 80 kDa that is widely represented in various secretory fluids, such as milk, saliva, tears, and nasal secretions...
s were found to be potent inhibitors of EV71 infection" and "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...
could be a potential anti-EV71 drug."
Taiwan
"Two outbreaks of hand-foot-and-mouth disease (HFMD) occurred in Taiwan between 1998 and 2000.Enteroviruses were isolated from a total of 1,892 patients in this laboratory during this period. Of the virus
isolates, enterovirus 71 (EV71) was diagnosed in 44.4% of the patients (132 of 297) in 1998, 2% (13 of 646) in
1999, and 20.5% (195 of 949) in 2000. Genetic analyses of the 5�-untranslated and VP1 regions of EV71 isolates
by reverse transcription-PCR and sequencing were performed to understand the diversity of EV71 in these
outbreaks of HFMD. Most EV71 isolates from the 1998 epidemic belonged to genotype C, while only one-tenth
of the isolates were genotype B. Interestingly, all EV71 isolates tested from 1999 to 2000 belonged to genotype
B. This study indicated that two genogroups of EV71 capable of inducing severe clinical illness have been
circulating in Taiwan. Furthermore, the predominant EV71 genotypes responsible for each of the two major
HFMD outbreaks within the 3-year period in Taiwan were different."
China
From 1999 to 2004, there were no epidemics of hand, foot, and mouth disease in ShenzhenShenzhen
Shenzhen is a major city in the south of Southern China's Guangdong Province, situated immediately north of Hong Kong. The area became China's first—and one of the most successful—Special Economic Zones...
, People's Republic of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
, but each year there were small, local outbreaks associated with only a few cases of neurological disease and no reported fatalities. Genetic analysis revealed 19 cases of EV71 among 147 children who had hand, foot, and mouth disease in Shenzhen
Shenzhen
Shenzhen is a major city in the south of Southern China's Guangdong Province, situated immediately north of Hong Kong. The area became China's first—and one of the most successful—Special Economic Zones...
during this time.
Until 2008, no large EV71 epidemic had been reported on the Chinese mainland, but sporadic infections were common in the southeast coastal area as well as inland regions, such as Beijing, Chongqing, and Jinan. From 1998 to 2004, the only EV71 viruses identified on mainland China belonged to the genotype C4, indicating far less variety in China than in Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
.
On May 3, 2008, Chinese health authorities reported a major outbreak of EV71 enterovirus in Fuyang city and other localities in Anhui, Zhejiang, and Guangdong provinces. As of May 3, 2008, 3736 cases occurring mainly in children have been reported, with 22 dead and 42 critically ill. Some 415 new cases have been reported in the last 24 hours in Fuyang City alone. As of May 5, 2008, 6,300 were sickened by the viral outbreak which killed another child, in Zhejiang
Zhejiang
Zhejiang is an eastern coastal province of the People's Republic of China. The word Zhejiang was the old name of the Qiantang River, which passes through Hangzhou, the provincial capital...
raising the death toll to 26 children, with 1,198 other children affected in that province alone. Specifically, an additional 5,151 cases were reported in Anhui
Anhui
Anhui is a province in the People's Republic of China. Located in eastern China across the basins of the Yangtze River and the Huai River, it borders Jiangsu to the east, Zhejiang to the southeast, Jiangxi to the south, Hubei to the southwest, Henan to the northwest, and Shandong for a tiny...
province with scores more in 4 other provinces. 8,531 cases of children infected with hand-foot-mouth disease (HFMD) were reported in China. All the children infected are aged below 6, with most of them being under 2. As of May 7 contagious HFMD led to 28 deaths. Xinhua reported the number of people infected, also rose by 4000 to 15,799.