Ross River Virus Infection
|1.0||January 2017||Full revision|
- Infectious Agent
- Notification Criteria
- Notification Procedure
- Reporting to NOCS
- Public Health Significance and Occurrence
- Clinical Features
- Mode of Transmission
- Incubation Period
- Period of Communicability
- Susceptibility and Resistance
- Preventive Measures
Ross River virus, which is an Alphavirus.
A confirmed case requires laboratory definitive evidence only.
A probable case requires laboratory suggestive evidence only.
Laboratory definitive evidence
Isolation of Ross River virus.
Detection of Ross River virus by nucleic acid testing
IgG seroconversion or a significant increase in antibody level (e.g. fourfold or greater rise in titre) to Ross River virus
Laboratory suggestive Evidence
Detection of Ross River virus IgM, AND Ross River virus IgG EXCEPT if a person is known to have had IgG to the virus detected in a specimen collected greater than 3 months earlier.
Notify all confirmed and probable cases of Ross River virus by facsimile, email or other electronic means.
Reporting to NOCS
Report confirmed and probable cases.
Public Health Significance and Occurrence
Ross River virus infection is a common and widespread arbovirus disease in Australia. It was first isolated in 1959 in Townsville. Outbreaks have since occurred in most states of Australia, mostly from February to May or after periods of high rainfall or high tides.
There is an ongoing high rate of infection in Queensland, with epidemic activity in some years.
Up to approximately half of those infected will develop symptoms of the disease. Disease symptoms are rare in young children.
Research into a vaccine is currently being carried out.
Ross River virus disease is a self-limiting, febrile illness characterized by arthralgia/arthritis especially of the wrists, knees, ankles and small joints of extremities. There may be rash, cervical lymphadenopathy and occasionally paraesthesia and tenderness of the palms and soles. Fatigue and malaise are often prominent. Prolonged symptoms, in some cases up to a year may occur.
The virus is maintained in a primary mosquito-mammal cycle, including marsupials, horses and fruit bats.
Mode of Transmission
Transmission is via infected mosquitoes. Ross River virus has been isolated from over 40 different mosquito species across Australia. The primary vectors identified in Queensland are the salt marsh mosquito Aedes vigilax and the fresh water mosquito Culex annulirostris. Other species implicated include Aedes notoscriptus, Aedes procax, and Coqillettidia linealis. Vectors are usually most active around dawn and dusk. Breeding sites and dispersion distances vary depending on the vector.
Transmission via blood transfusion is possible however the risk is very low due to screening procedures.
Usually 7-9 days (range 3 to 21 days).
Period of Communicability
There is no evidence of human to human transmission.
Susceptibility and Resistance
Asymptomatic infections are common especially in children.
Public Health investigation of individual cases is not warranted.
Identify vector breeding sites and undertake appropriate mosquito control measures.
Issue media alerts for the general public including preventive measure as outlined below.
The best prevention is to avoidance of mosquito bites by:
- Avoiding outdoor activities when mosquitoes are most active, around dawn and dust
- Wearing loose, light-coloured clothing with long sleeves, long trousers and socks (mosquitoes can bite through tight-fitting clothes)
- Appling protective mosquito repellent containing diethyl toluamide (DEET) or picaridin to exposed areas of skin and reapply as directed by the manufacturer. Lotions and gels are more effective and long lasting than sprays
- Ensuring flyscreens and water tank screen are in good order
- Using mosquito lanterns, coils or plug-in repellent devises to protect against mosquito bites
- Empting containers holding water around the house weekly.
Harley D., Sleigh A., Ritchie S., Ross River Virus Transmission, Infection and Disease: A Cross-Disciplinary Review, Clinical Microbiology Reviews, 2001, Oct, 909-932.
Heymann D (Ed), Control of Communicable Diseases Manual, 2015, 20th Edition, American Public Health Association: Washington.
Hoad V. C, Speers A. J, Keller A. J, et al, First reported case of transfusion-transmitted Ross River virus infection, Medical Journal of Australia, 2015, 202 (5), 267269.
Tong S., Ross River virus disease in Australia: epidemiology, sociology and public health response, Internal Medicine Journal, 2004, 34, 58-60
Wressnigg N., van der Velden M. V., Portsmouth D., et al, An inactivated ross river virus vaccine is well tolerated and immunogenic in an adult population in a randomized phase 3 trial, Clinical And Vaccine Immunology, 2015, 22 (3), 267-73.