Ross River Virus
   HOME

TheInfoList



OR:

Ross River virus (RRV) is a small encapsulated single-strand
RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...
'' Alphavirus''
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to Australia,
Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...
and other islands in the South Pacific. It is responsible for a type of
mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...
-borne, non-lethal but extremely debilitating
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 forc ...
known as Ross River fever, previously termed "epidemic polyarthritis". There is no known cure, and it can last in the host's system for up to 20 years. The virus is suspected to be
enzootic Enzootic describes the situation where a disease or pathogen is continuously present in at least one species of non-human animal in a particular region. It is the non-human equivalent of endemic. In epizoology, an infection is said to be "''enzo ...
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 virus genus '' Alphavirus'', which is part of the family ''
Togaviridae {{Commonscat, Viruses by family This category is for articles about virus families (or redirects to such articles). There should be no subcategories. families Families (biology) ...
''. 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 belongs to the SF antigenic complex of the genus Alphavirus. The virions (virus particles) themselves contain their genome in a protein capsid 700 Å in diameter. They are characterised by the presence of two
glycoproteins Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known a ...
(E1 and E2) embedded as trimeric dimers in a host-derived lipid
envelope An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter (message), letter or Greeting card, card. Traditional envelopes are made from sheets of paper cut to one o ...
. Because RRV is transmitted by
mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...
s, it is considered an
arbovirus Arbovirus is an informal name for any virus that is Transmission (medicine), transmitted by arthropod Vector (epidemiology), vectors. The term ''arbovirus'' is a portmanteau word (''ar''thropod-''bo''rne ''virus''). ''Tibovirus'' (''ti''ck-''bo ...
, a non-taxonomic term for viruses borne by arthropod
vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...
s.


History

In 1928, an outbreak of acute febrile arthritis was recorded in
Narrandera Narrandera ( ), until around 1949 also spelled "Narandera", is a town located in the central Riverina region of south-western New South Wales, Australia. The town lies on the junction of the Newell Highway, Newell and Sturt Highway, Sturt highwa ...
and
Hay Hay is grass, legumes, or other herbaceous plants that have been cut and dried to be stored for use as animal fodder, either for large grazing animals raised as livestock, such as cattle, horses, goats, and sheep, or for smaller domesticate ...
in
New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...
, Australia. In 1943, several outbreaks of
arthralgia Arthralgia () literally means ' joint pain'. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication Medication (also called medicament, medicine, pharmaceuti ...
and
arthritis Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...
were described in the
Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...
,
Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...
and the
Schouten Islands The Biak Islands (, also Schouten Islands or Geelvink Islands) are an island group of Southwest Papua province, eastern Indonesia in the Cenderawasih Bay (or Geelvink Bay) 50 km off the north-western coast of the island of New Guinea. Th ...
, off the northern coast of
Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...
. The name "epidemic polyarthritis" was coined for the disease. In 1956, an epidemic occurred in the Murray Valley which was compared to "acute viral polyarthritis" caused by the Chikungunya virus. The Australian disease seemed to progress in a milder fashion. In 1956,
serological Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given mi ...
testing suggested an unknown new species of alphavirus (group A arbovirus) was the likely culprit. In July and August 1956 and 1957, a virus recovered from
mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...
es collected near
Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...
, Japan, and was dubbed ''Sagiyama virus''. For a time, it was thought to be a separate species, but is now considered conspecific with ''Ross River virus''.ICTV 7th Report van Regenmortel, M.H.V., Fauquet, C.M., Bishop, D.H.L., Carstens, E.B., Estes, M.K., Lemon, S.M., Maniloff, J., Mayo, M.A., McGeoch, D.J., Pringle, C.R. and Wickner, R.B. (2000). Virus taxonomy. Seventh report of the International Committee on Taxonomy of Viruses. Academic Press, San Diego. p. 887 https://ictv.global/ictv/proposals/ICTV%207th%20Report.pdf In 1959, a new alphavirus was identified in samples from a mosquito ('' Aedes vigilax'') trapped in the Ross River, located in
Townsville The City of Townsville is a city on the north-eastern coast of Queensland, Australia. With a population of 201,313 as of 2024, it is the largest settlement in North Queensland and Northern Australia (specifically, the parts of Australia north of ...
, 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 suckling
mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
. 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. The largest-ever outbreak of the virus was in 1979–1980 and occurred in the western Pacific. The outbreak involved the islands of
Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...
,
Samoa Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited ...
, the
Cook Islands The Cook Islands is an island country in Polynesia, part of Oceania in the South Pacific Ocean. It consists of 15 islands whose total land area is approximately . The Cook Islands' Exclusive Economic Zone (EEZ) covers of ocean. Avarua is its ...
, and
New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...
. However, RRV was later isolated in humans following a series of epidemic polyarthritis outbreaks in
Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...
,
Samoa Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited ...
and the
Cook Islands The Cook Islands is an island country in Polynesia, part of Oceania in the South Pacific Ocean. It consists of 15 islands whose total land area is approximately . The Cook Islands' Exclusive Economic Zone (EEZ) covers of ocean. Avarua is its ...
during 1979. RRV was isolated in an Australian patient suffering from Ross River fever in 1985. In 2010, Ross River virus was found to have made its way to the Aundh area in
Pune Pune ( ; , ISO 15919, ISO: ), previously spelled in English as Poona (List of renamed Indian cities and states#Maharashtra, the official name until 1978), is a city in the state of Maharashtra in the Deccan Plateau, Deccan plateau in Western ...
, India, and spread to other parts of the city. The RRV infection is characterised by inflammation and pain to multiple joints. Hydration by sufficient fluid intake is recommended, to ensure that the fever does not rise to very dangerous levels. It is also recommended that a doctor be consulted immediately as regular paracetamol 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 In infectious disease ecology and epidemiology, a natural reservoir, also known as a disease reservoir or a reservoir of infection, is the population of organisms or the specific environment in which an infectious pathogen naturally lives and r ...
such as large
marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...
mammals.
Antibodies An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that caus ...
to Ross River virus have been found in a wide variety of
placental Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished ...
and marsupial mammals, and also in a few bird species. It is not presently known what reservoir hosts support ''Ross River virus'' in metropolitan areas such as
Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...
. The southern saltmarsh mosquito ('' Aedes camptorhynchus''), which is known to carry the Ross River virus, was discovered in
Napier, New Zealand Napier ( ; ) is a city on the eastern coast of the North Island of New Zealand and the seat of the Hawke's Bay region. It is a beachside city with a seaport, known for its sunny climate, esplanade lined with Norfolk pines, and extensive Art D ...
, in 1998. Due to an 11-year program by the New Zealand Ministry of Health, and later the Ministry of Agriculture & Fisheries, the species was declared completely eradicated from New Zealand in July 2010. As of September 2006, there has never been a report of a case of Ross River virus acquired within New Zealand. Separate mosquito species may act as vector, widespread across areas and seasonal/geographical locations. In southern and northern regions, the ''
Aedes ''Aedes'' (also known as the tiger mosquito) is a genus of mosquitoes originally found in tropical and subtropical zones, but now found on all continents except Antarctica. Some species have been spread by human activity: ''Aedes albopictus'', ...
'' group (''A. camptorhynchus'' and ''A. vigilax'') are the main RRV carriers. However, inland the '' Culex annulirostris'' is the main carrier with ''Aedes'' mosquitoes becoming active during wet seasons.


Western Australia

Due to the expansion and housing demand in the south west of
Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...
, residential development is occurring closer to wetlands in spite of the fact that the ecosystem is known for mosquito breeding. Particularly in the Peel region where living near water is desirable for aesthetic value. Over the decade of June 2011 – 2012 the population increased by 44,000 residents averaging a rate of 4.5 per cent per annum. In June 2013 the Peel region accounted for approximately five per cent of the State's population and predicted to account for around 6.7 per cent of Western Australia's population by 2031. A study comparing the risk of contracting Ross River virus (RRV) and the distance of the dwellings from Muddy Lakes. The reports showed within a one kilometre buffer zone there were approximately 1550 mosquitos in traps per night with 89% of them being ''Ae. camptorhynchus'' decreasing to approximately 450 mosquitos with 57% ''Ae. camptorhynchus'' at the six kilometre buffer zone. The study suggests that there is a significantly higher risk of contracting RRV when living closer to Muddy Lakes however, there was a rise in the two kilometre buffer zone of 3700 mosquitos with 94% ''Ae. camptorhynchus''. A similar trend in the study same study conducted in the Peel region resulting in less mosquitoes the further away the buffer distance. In 1995–96 Leschenault and Capel-Busselton were affected by an outbreak of 524 cases of RRV disease. Although this occurred around a decade ago, the data analysed the total RRV cases per 1000 persons for each 500m buffer zone. This shows an elevated risk of contracting the disease if living in close proximity to the Leschenault Estuary, within 2 km being the strongest disease risk gradient. Evidence shows that there is a strong correlation between contracting RRV when living in close proximity to wetlands in the south west of Western Australia. However, due to continuous growth and development of residential areas around these wetlands it is expected that problems with RRV disease will occur.


Risks

There are several factors that can contribute to an individual's risk for Ross River virus in Australia. These risks were trialed in a study conducted in tropical Australia which illustrate that factors such as camping, light coloured clothing, exposure to certain flora and fauna and specific protective mechanisms are able to increase or decrease the likelihood of contracting the virus. By increasing the frequency of camping the individual's risk increases eight-fold, suggesting that an increased exposure to wildlife increases risk. This is shown by the narrow 95% confidence interval of 1.07–4.35 within the study. For example, an individual's exposure to
kangaroo Kangaroos are marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use, the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern gre ...
s, wallabies and bromeliad plants also increased risk, suggesting that they are reservoirs for infection, breeding sites for mosquitoes and potential vectors of the virus. Ross River virus antibodies have been found in captive populations of tammar wallabies and wallaroos in urban areas in New South Wales, Australia, and are potential
reservoirs A reservoir (; ) is an enlarged lake behind a dam, usually built to store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrup ...
for the virus. Although these areas show a higher risk for the virus, humans should still enjoy the wildlife but consider that preventive mechanisms as increasingly important while camping.


Prevention

Ross River virus can be easily prevented through small behavioural mechanisms which should be of high importance in tropical areas and during participation of outdoor activities. Firstly, insect repellent should be rigorously used as to prevent bites from insects that specifically include mosquitoes which are vectors that carry the disease. A study in tropical Australia shows a very narrow 95% confidence interval of 0.20–1.00 for a decrease in Ross River virus risk as a result of increased use of insect repellent, suggesting a strong correlation between the two. Following, burning citronella candles are based on the same principle, that it repels insects that are vectors of the virus. Burning such candles also show a strong correlation with decreased Ross River virus risk shown in the same study with a narrow 95% confidence interval of 0.10–0.78. Secondly, wearing light coloured clothing decrease the risk of Ross River virus three-fold. This is again based on the repelling of vectors such as mosquitoes through the use of bright colours. Lastly, high risk areas should be minimised by mechanisms of prevention that are applied within households. For example, screens should be fitted to windows and doors to prevent entry of insects carrying the virus and potential breeding areas such as open water containers or water holding plants should be removed. Therefore, specific climatic environments should be assessed for high risk factors and the appropriate precautions should be taken in response.


Lab research

The study of RRV has been recently facilitated by a mouse model. Inbred mice infected with RRV develop hind-limb arthritis/arthralgia. The disease in mice, similar to humans, is characterised by an inflammatory infiltrate including
macrophage Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...
s 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.


Symptoms

Ross River virus can cause multiple symptoms in someone who is infected, the most common being
arthritis Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...
or joint pain. Other symptoms include a
rash A rash is a change of the skin that 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, cracke ...
on the limbs of the body, which often occurs roughly 10 days after arthritis begins.
Lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...
s may enlarge, most commonly in the arm pits or groin region, and rarely a feeling of 'pins and needles' in the persons hands and feet, but only occurs in a small number of people. The virus also causes moderate symptoms in
horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...
s. The symptoms of Ross River virus are important to recognise for early diagnosis and therefore early treatment. Symptoms have been illustrated in a case report of an infected Thuringian traveller returning from South-East Australia. This case showed flu-like symptoms that include
fever Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...
,
chills Chills is a feeling of coldness occurring during a high fever, but sometimes is also a common symptom which occurs alone in specific people. It occurs during fever due to the release of cytokines and prostaglandins as part of the inflammatory ...
,
headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...
and pains in the body. Additionally,
joint pain Arthralgia () literally means 'joint pain'. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication Medication (also called medicament, medicine, pharmaceutic ...
arose in which some joints become swollen and joint stiffness was particularly noticeable. A clinical examination of the infected individual shows a significant decrease of specific antibodies despite the normal blood count levels. A rash is a good indication that is likely to occur but usually disappears after ten days. The symptoms of Ross River virus are important to be aware of so that early treatment can be administered before the virus worsens. The time between catching the disease and experiencing symptoms is anywhere between three days to three weeks, usually it takes about 1–2 weeks. A person can be tested for Ross River virus by a
blood test A blood test is a medical laboratory, laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose ...
, other illnesses may need to be excluded before diagnosis.


Diagnosis

Testing for Ross River virus should occur in patients who are experiencing acute polyarthritis, tiredness and/or rashes (~90%) with a history of travel within areas prone to infection from the virus. Serology (blood tests) is the appropriate manner by which to diagnose Ross River virus. Within 7 days of infection, the virus produces Immunoglobulin M (IgM) and is a presumptive positive diagnosis. IgM may persist for months or even years and therefore false positives may be triggered by Barmah Forest virus,
rubella Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus. This disease is often mild, with half of people not realizing that they are infected. A rash may start around two weeks after exposure and ...
,
Q fever Q fever or query fever is a disease caused by infection with ''Coxiella burnetii'', a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats, and other domestic mammals, including ...
or rheumatoid factor. To completely test for Ross River virus, a second serology test must be conducted 10–14 days after the first. The patient may then be declared positive for Ross River virus infection if there is a 4-fold increase of IgM antibody count.


Ross River fever

Ross River fever is also known as ''Ross River virus infection'' or ''Ross River virus disease''. Ross River virus is named after the Ross River in Townsville, which is the place where it was first identified. Ross River fever is the most common mosquito-borne disease in Australia, and nearly 5000 people are reported to be infected with the virus each year.


References


External links


Ross River & Barmah Forest
University of Sydney, Department of Medical Entomology {{Taxonbar, from=Q660537, from2=Q7399312 Animal viruses Human viruses Species described in 1959 Viruses described in the 20th century Arboviruses Alphaviruses