Ross River virus
Encyclopedia
Ross River virus is a small encapsulated single-strand RNA
alphavirus
endemic
to Australia
, Papua New Guinea
and other islands in the South Pacific
. It is responsible for a type of mosquito
-borne non-lethal but debilitating tropical disease
known as Ross River fever
, previously termed "epidemic polyarthritis
". The virus is suspected to be enzootic
in populations of various native Australian mammals, and has been found on occasion in horses.
genus Alphavirus
, which is part of the family Togaviridae
. The alphaviruses are a group of small enveloped single-strand positive-sense RNA viruses. RRV belongs to a subgroup of "Old World" (Eurasian-African-Australasian) alphaviruses, and is considered closely related to Sagiyama virus
.
The virions themselves contain their genome in a protein capsid 700 Å
in diameter. They are characterised by the presence of two glycoproteins (E1 and E2) embedded as trimeric dimers in a host-derived lipid envelope.
Because RRV is transmitted through mosquito
vector it is considered an arbovirus
, a non-taxonomic term for viruses borne by arthropod vectors.
in New South Wales
, Australia
. In 1943 several outbreaks of arthralgia and arthritis were described in the Northern Territory
, Queensland
and the Schouten Islands
, off the northern coast of Papua New Guinea
. The name epidemic polyarthritis was coined for this disease. In 1956 an epidemic occurred in the Murray Valley which was compared to "acute viral polyarthritis" caused by Chikungunya virus. The Australian disease seemed to progress in milder fashion. In 1956 serological testing suggested an unknown new species of alphavirus (group A arbovirus) was the likely culprit.
In 1959, a new alphavirus was identified in mosquito (Ochlerotatus vigilax) samples trapped near Ross River, near Townsville
, Queensland
, Australia
. Further serological testing showed that patients who had suffered "epidemic polyarthritis" in Queensland had antibodies to the virus. The new virus was named Ross River virus, and the disease Ross River fever
.
The virus itself was first isolated in 1972 using sucking mice. It was found that RRV isolated from human serum could kill mice. However, the serum containing the virus that was used had come from an Aboriginal boy from Edward River
, North Queensland. The child had a fever and a rash but no arthritis making the link between RRV and Ross River fever less than concrete.
However RRV was later isolated in humans following a series of epidemic polyarthritis outbreaks in Fiji
, Samoa
and the Cook Island
s, during 1979. RRV was isolated in an Australian patient suffering from Ross River fever in 1985.
In 2010, the Ross River Virus was found to have made its way to the Aundh
area in Pune
, India
and spread to other parts of the city. A tourist to Australia probably returned infected with the virus. The RRV infection is characterized by very high fever, pain in the joints, loss of appetite and weakness. Hydration by sufficient fluid intake is recommended to ensure that the fever does not rise to very dangerous levels. It is recommended that a doctor be consulted immediately as regular paracetemol gives only temporary reprieve from the fever.
areas such as Brisbane.
The Southern Saltmarsh mosquito (Aedes camptorhynchus
) which is known to carry the Ross River virus was discovered in New Zealand in 1998, and there is an ongoing eradication program by the New Zealand Ministry of Health, involving spraying the insecticide Bti on infested areas. As of June 2007 there have been no reported cases of Ross River Virus that arose in New Zealand.
RNA virus
An RNA virus is a virus that has RNA as its genetic material. This nucleic acid is usually single-stranded RNA but may be double-stranded RNA...
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...
endemic
Endemic (epidemiology)
In epidemiology, an infection is said to be endemic in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic in the UK, but malaria is not...
to 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...
, Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
and other islands in the South Pacific
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
. It is responsible for a type of 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...
-borne non-lethal but debilitating tropical disease
Tropical disease
Tropical diseases are diseases that are prevalent in or unique to tropical and subtropical regions. The diseases are less prevalent in temperate climates, due in part to the occurrence of a cold season, which controls the insect population by forcing hibernation. Insects such as mosquitoes and...
known as Ross River fever
Ross River Fever
Ross River Fever is a mosquito-borne infectious disease caused by infection with the Ross River virus. The illness is typically characterised by an influenza-like illness and polyarthritis...
, previously termed "epidemic 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:...
". The virus is suspected to be enzootic
Endemic (epidemiology)
In epidemiology, an infection is said to be endemic in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic in the UK, but malaria is not...
in populations of various native Australian mammals, and has been found on occasion in horses.
Classification and morphology
Taxonomically Ross River virus belongs to the virusVirus
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...
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...
, which is part of the family Togaviridae
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;...
. The alphaviruses are a group of small enveloped single-strand positive-sense RNA viruses. RRV belongs to a subgroup of "Old World" (Eurasian-African-Australasian) alphaviruses, and is considered closely related to Sagiyama virus
Sagiyama virus
Sagiyama virus is an arthropod borne virus recovered from mosquitoes collected during July and August 1956 and 1957 near Tokyo, Japan. Sagiyama virus is in a member of the genus Alphavirus in the family Togaviridae, possessing single positive strand RNA genome ....
.
The virions themselves contain their genome in a protein capsid 700 Å
Å
Å represents various sounds in several languages. Å is part of the alphabets used for the Alemannic and the Bavarian-Austrian dialects of German...
in diameter. They are characterised by the presence of two glycoproteins (E1 and E2) embedded as trimeric dimers in a host-derived lipid envelope.
Because RRV is transmitted through 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...
vector it is considered an 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:...
, a non-taxonomic term for viruses borne by arthropod vectors.
History
In 1928 an outbreak of acute febrile arthritis was recorded in Narrandera and HayHay
Hay is grass, legumes or other herbaceous plants that have been cut, dried, and stored for use as animal fodder, particularly for grazing livestock such as cattle, horses, goats, and sheep. Hay is also fed to pets such as rabbits and guinea pigs...
in New South Wales
New South Wales
New 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...
, 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...
. In 1943 several outbreaks of arthralgia and arthritis were described in the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
, 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...
and the Schouten Islands
Schouten Islands
The Indonesian Schouten Islands are an island group of Papua province, eastern Indonesia in the Cenderawasih Bay 50 km off the north-western coast of the island of New Guinea...
, off the northern coast of Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
. The name epidemic polyarthritis was coined for this disease. In 1956 an epidemic occurred in the Murray Valley which was compared to "acute viral polyarthritis" caused by Chikungunya virus. The Australian disease seemed to progress in milder fashion. In 1956 serological testing suggested an unknown new species of alphavirus (group A arbovirus) was the likely culprit.
In 1959, a new alphavirus was identified in mosquito (Ochlerotatus vigilax) samples trapped near Ross River, near Townsville
Townsville, Queensland
Townsville 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...
, 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...
. Further serological testing showed that patients who had suffered "epidemic polyarthritis" in Queensland had antibodies to the virus. The new virus was named Ross River virus, and the disease Ross River fever
Ross River Fever
Ross River Fever is a mosquito-borne infectious disease caused by infection with the Ross River virus. The illness is typically characterised by an influenza-like illness and polyarthritis...
.
The virus itself was first isolated in 1972 using sucking mice. It was found that RRV isolated from human serum could kill mice. However, the serum containing the virus that was used had come from an Aboriginal boy from Edward River
Edward River
The Edward River is a river in the south west Riverina region of New South Wales, Australia. The river is an anabranch of the Murray River, the longest river in Australia....
, North Queensland. The child had a fever and a rash but no arthritis making the link between RRV and Ross River fever less than concrete.
However RRV was later isolated in humans following a series of epidemic polyarthritis outbreaks in Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
, Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...
and the Cook Island
Cook Island
Cook Island may refer to* Cook Island, South Sandwich Islands, central island in Southern Thule* Cook Island of Kiritimati, Kiribati* Cook Islands, self governing democracy in the Pacific, in free association with New Zealand, of which "Cook Island" is the adjectival demonym* Cook Island Aquatic...
s, during 1979. RRV was isolated in an Australian patient suffering from Ross River fever in 1985.
In 2010, the Ross River Virus was found to have made its way to the Aundh
Aundh (Pune)
Aundh is a suburb in the North-West of Pune in Maharashtra, India. It was earlier known for its Chest Hospital. Now it is known for its posh localities populated by software engineers...
area in Pune
Pune
Pune , is the eighth largest metropolis in India, the second largest in the state of Maharashtra after Mumbai, and the largest city in the Western Ghats. Once the centre of power of the Maratha Empire, it is situated 560 metres above sea level on the Deccan plateau at the confluence of the Mula ...
, 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...
and spread to other parts of the city. A tourist to Australia probably returned infected with the virus. The RRV infection is characterized by very high fever, pain in the joints, loss of appetite and weakness. Hydration by sufficient fluid intake is recommended to ensure that the fever does not rise to very dangerous levels. It is recommended that a doctor be consulted immediately as regular paracetemol gives only temporary reprieve from the fever.
Ecology
In rural and regional areas of Australia, the continued prevalence of Ross River virus is thought to be supported by natural reservoirs such as large marsupial mammals. Antibodies to Ross River virus have been found in a wide variety of placental and marsupial mammals, and also in a few bird species. It is not presently known what reservoir hosts support Ross River virus in metropolitanMetropolitan area
The term metropolitan area refers to a region consisting of a densely populated urban core and its less-populated surrounding territories, sharing industry, infrastructure, and housing. A metropolitan area usually encompasses multiple jurisdictions and municipalities: neighborhoods, townships,...
areas such as Brisbane.
The Southern Saltmarsh mosquito (Aedes camptorhynchus
Aedes camptorhynchus
Aedes camptorhynchus, or Southern Saltmarsh mosquito, is responsible for transmitting the Ross River virus, which causes Ross River fever.The mosquito had become established in New Zealand but was declared to be eradicated in 2010.-External links:...
) which is known to carry the Ross River virus was discovered in New Zealand in 1998, and there is an ongoing eradication program by the New Zealand Ministry of Health, involving spraying the insecticide Bti on infested areas. As of June 2007 there have been no reported cases of Ross River Virus that arose in New Zealand.
Lab research
The study of RRV has been recently facilitated by a mouse model. Inbred mice infected with RRV develop hind-limb arthritis/arthralgia which is similar to human disease. The disease in mice, similar to humans, is characterized by an inflammatory infiltrate including macrophages which are immunopathogenic and exacerbate disease. Furthermore, recent data indicate that the serum component, C3, directly contributes to disease since mice deficient in the C3 protein do not suffer from severe disease following infection.Ross River fever
Ross River fever is also known as Ross River virus infection or Ross River virus disease.External links
- Ross River & Barmah Forest University of Sydney, Department of Medical Entomology