The O'nyong'nyong virus or O'nyong-nyong virus is a virus

Virus

A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

 first isolated by the Uganda Virus Research Institute

Uganda Virus Research Institute

The Uganda Virus Research Institute , located in Entebbe, Uganda, was established in 1936 as the Yellow Fever Research Institute by the Rockefeller Foundation. In 1950, after gaining regional recognition it was renamed the East African Virus Research institute...

 in Entebbe

Entebbe

Entebbe is a major town in Central Uganda. Located on a Lake Victoria peninsula, the town was at one time, the seat of government for the Protectorate of Uganda, prior to Independence in 1962...

, Uganda

Uganda

Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...

 in 1959. It is a togavirus

Togaviridae

The Togaviridae are a family of viruses, including the following genera:* Genus Alphavirus; type species: Sindbis virus, Eastern equine encephalitis virus, Western equine encephalitis virus, Venezuelan equine encephalitis virus, Ross River virus, O'nyong'nyong virus, Chikungunya* Genus Rubivirus;...

 (family Togaviridae), genus Alphavirus

Alphavirus

In biology and immunology, an alphavirus belongs to the group IV Togaviridae family of viruses, according to the system of classification based on viral genome composition introduced by David Baltimore in 1971. Alphaviruses, like all other group IV viruses have a positive sense single stranded RNA...

and is closely related to the Chikungunya

Chikungunya

Chikungunya virus is an insect-borne virus, of the genus Alphavirus, that is transmitted to humans by virus-carrying Aedes mosquitoes. There have been recent breakouts of CHIKV associated with severe illness...

 and Igbo Ora viruses. The name comes from the Nilotic language

Nilotic languages

The Nilotic languages are a group of Eastern Sudanic languages spoken across a wide area between southern Sudan and Tanzania by the Nilotic peoples, particularly associated with cattle-herding...

 of Uganda and Sudan

Sudan

Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...

 and means “weakening of the joints". The virus can infect humans and may cause disease.

Transmission

O'nyong'nyong virus is transmitted by bites from an infected mosquito

Mosquito

Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...

. It is the only virus whose primary vectors are anopheline

Anopheles

Anopheles is a genus of mosquito. There are approximately 460 recognized species: while over 100 can transmit human malaria, only 30–40 commonly transmit parasites of the genus Plasmodium, which cause malaria in humans in endemic areas...

 mosquitoes (Anopheles funestus and Anopheles gambiae

Anopheles gambiae

Anopheles gambiae is a complex of at least seven morphologically distinguishable species of mosquitoes in the genus Anopheles. This complex was recognised in the 1960s and includes the most important vectors of malaria in sub-Saharan Africa and the most efficient malaria vectors known.This species...

).

Presentation

Common symptoms of infection with the virus are polyarthritis

Polyarthritis

Polyarthritis is any type of arthritis which involves 5 or more joints simultaneously. It is usually associated with autoimmune conditions.Polyarthritis may be experienced at any age and is not gender specific.-Causes:...

, rash

Rash

A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...

 and fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

. Other symptoms include eye pain, chest pain, lymphadenitis and lethargy. No fatalities due to infection are known.

Epidemics

There have been two epidemics of O’nyong’nyong fever. The first occurred from 1959 to 1962, spreading from Uganda to Kenya

Kenya

Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

, Tanzania

Tanzania

The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

, Zaire (Democratic Republic of the Congo

Democratic Republic of the Congo

The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

), Malawi

Malawi

The Republic of Malawi is a landlocked country in southeast Africa that was formerly known as Nyasaland. It is bordered by Zambia to the northwest, Tanzania to the northeast, and Mozambique on the east, south and west. The country is separated from Tanzania and Mozambique by Lake Malawi. Its size...

 and Mozambique

Mozambique

Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...

, and affecting over two million people. This was one of the largest arbovirus

Arbovirus

Arbovirus is a term used to refer to a group of viruses that are transmitted by arthropod vectors. The word arbovirus is an acronym . Some arboviruses are able to cause emergent disease.-Transmission:...

 epidemics recorded. The first virus isolates were obtained during this outbreak from mosquitoes and human blood samples collected from Gulu

Gulu

Gulu is a city in Northern Uganda. It is the commercial and administrative centre of Gulu District. The city is located at 2˚46'48N 32˚18'00E, on the metre gauge railway from Tororo to Pakwach. Gulu is located approximately , by road, north of Kampala, Uganda's capital and largest city...

 in northern Uganda in 1959.

The second epidemic in 1996-1997 affected 400 people and was confined to Uganda. The 35-year hiatus between the two outbreaks and evidence of an outbreak in 1904-1906 in Uganda indicates a 30-50 year cycle for epidemics.

Strains

The ONNV (o'nyong-nyong virus) has at least three major subtypes, or strains, which genomic sequences are currently available on genome databases.

External links

• Material Safety Data Sheet from the Public Health Agency of Canada
  Public Health Agency of Canada
  The Public Health Agency of Canada is an agency of the Government of Canada that is responsible for public health, emergency preparedness, and response and infectious and chronic disease control and prevention...