Clinical Diagnosis, Treatment, and Prevention of Ross River Virus Disease

Epidemiology

Ross River virus is an RNA virus in the genus Alphavirus (family Togaviridae) that was discovered near Ross River in Queensland, Australia in 1963.

Ross River virus is endemic in Australia and Papua New Guinea. There are approximately 4,000 cases of Ross River virus disease reported in Australia each year. Most cases there occur from January through April, but in some areas, disease occurs year-round.

There was a large outbreak in 1979–1980 in many South Pacific Islands including Fiji, American Samoa, New Caledonia, and the Cook Islands with over 50,000 reported cases. Since that time, cases have been reported in several travelers to Fiji, and serosurveys suggest that Ross River virus is either established or has been reintroduced multiple times in at least some Pacific Island countries.

Clinical features

Patients with Ross River virus disease most commonly report polyarthritis, fever, fatigue and rash. Arthritis is usually symmetrical and involves peripheral joints, including knees, ankles, wrists, fingers, and metacarpophalangeal joints. Rash occurs primarily on the limbs and trunk and is typically maculopapular, with purpuric and vesicular rashes less common. Most symptoms resolve after a few weeks, but joint pain and fatigue can persist for six months or more. No fatal cases of Ross River virus disease have been reported.

Diagnosis

The differential diagnosis will vary depending on the travel destination of the patient. In travelers to Australia, it might include other arboviral diseases, such as Barmah Forest virus disease, or non-arboviral diseases such as adenoviral, enteroviral, or rickettsial infections. In a traveler to Papua New Guinea or Pacific Island nations, possible arboviral diseases also include dengue, chikungunya, and Zika virus disease.

Testing for Ross River virus infection can be performed at CDC. There are no commercially available tests for Ross River virus infection in the United States.

Please contact your state health department if you have a patient with an acute illness that might be compatible with Ross River virus disease (including appropriate travel history). They can assist you with determining if samples should be sent to the CDC Arbovirus Diagnostic Laboratory for further testing. Specimens should be submitted to CDC through state health departments. All results will be sent from CDC to the appropriate state health department.

Treatment and prevention

Currently there are no specific medications for Ross River virus disease. Supportive care is recommended for any patient suspected of having Ross River virus disease. Over-the-counter pain relievers, rest, fluids, and physical therapy can be used to relieve some symptoms. Patients should be advised to avoid aspirin containing drugs or other nonsteroidal anti-inflammatory drugs if dengue virus disease is suspected or has not been ruled out. In severe cases, patients may need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing care.

No Ross river virus vaccines are available for use in humans. In the absence of a vaccine, prevention of Ross River virus disease depends on personal protective measures to decrease exposure to infected mosquitoes. This includes using insect repellent, wearing long-sleeved shirts and pants, and treating clothing and gear with 0.5% permethrin. Travelers should choose a hotel or lodging with air conditioning or screens on windows and doors or use mosquito nets.

More information about preventing mosquito bites while traveling is available at CDC Mosquitoes website.

Ross River virus can rarely be transmitted through blood transfusions. People with Ross River virus infection should not donate blood for 120 days (4 months) after their illness. Ross River virus infections temporally associated with blood transfusion should be reported promptly to the appropriate state health department.