NAME: Sindbis virus (SINV) Footnote 1-4.
SYNONYM OR CROSS REFERENCE: Epidemic polyarthritis and rash, Sindbis virus disease, SIN, SINV, Ockelbo disease or August-September disease in Sweden Footnote 3, Pogosta disease in Finland, and Karelian fever in Russia1-6.
CHARACTERISTICS: Of the genus Alphavirus, and a member of the Togaviridae family. Virions are spherical to pleomorphic (70 nm in diameter), consisting of an envelope and nucleocapsid. The non-segmented genome consists of a single molecule of linear positive-sense single-stranded RNA Footnote 3Footnote 7Footnote 8.
PATHOGENICITY/TOXICITY: Sindbis fever in humans is a self-limiting, mild, febrile disease with vesicular exanthema and arthralgia; however, clinically unapparent infections are common. The disease begins with a sudden onset of fever, headache, and arthralgia (mainly of the smaller joints on hands and feet) Footnote 7. During the acute phase, typical symptoms are arthritis, itching rash, fatigue, mild fever, headache, and muscle pain that usually occur within the first 2 days of illness Footnote 9. Ankle, finger, wrist, and knee joints are most commonly affected during the acute phase. A maculopapular and, later, vesicular rash develops on body and limbs Footnote 7. The rash is distributed diffusely over the trunk and limbs and affects the palms and soles. Most patients recover within 14 days Footnote 10. In 50% of the patients, joint symptoms last for 12 months Footnote 9 to 2.5 years Footnote 5Footnote 11. Occasionally there is throat inflammation Footnote 7.
EPIDEMIOLOGY: Sindbis virus disease is a common occurrence in Africa, Asia, Australia, Europe, Middle East, Scandinavia and Russia Footnote 4Footnote 7Footnote 8Footnote 12. The annual incidence rate in endemic regions of affected countries ranges from 2.7/100,000 in Finland and 2.9/100,000 in Sweden to 18/100,000 in Northern Karelia Footnote 12Footnote 13. This is the most widely distributed of all known arboviruses, affecting all age groups Footnote 6. Children are often infected, but develop only a subclinical disease Footnote 6Footnote 14. Morbidity is highest in 45 to 65 year old females Footnote 13. Most clinical cases in Finland are reported during August and September Footnote 8.
HOST RANGE: Humans, resident or migratory or wild birds (major and amplifying hosts), and, on occasion, small mammals and amphibians Footnote 3Footnote 10. Sindbis virus can infect a wide variety of vertebrates and has been extensively studied in mice as a model for acute encephalitis Footnote 10.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Transmitted via the bite of numerous ornithophilic mosquito species (Anopheles, Mansonia, Aedes, Culiseta and Culex species) Footnote 3Footnote 6Footnote 7. Sindbis virus has also been isolated from ticks suggesting that they may also transmit the virus Footnote 15Footnote 16.
COMMUNICABIILTY: No evidence of direct person-to-person transmission Footnote 2.
RESERVOIR: Wild birds are the natural reservoir (probably asymptomatic) Footnote 7. Thrushes are the main amplifying hosts, but also the fieldfare and redwing. Large passerine species have higher infection prevalence than small species Footnote 17. Resident birds and migratory birds may contribute to the epidemiology Footnote 8.
ZOONOSIS: Yes, indirectly via mosquitoes.
VECTORS: Primarily Aedes, Culex, and Culiseta spp., and possibly ticks Footnote 6.
SUSCEPTIBILITY TO DISINFECTANTS: Sensitive to 70% (v/v) ethanol, sodium hypochlorite (500 to 1,000 ppm free chlorine), accelerated hydrogen peroxide, and quaternary ammonium compounds Footnote 19Footnote 20.
PHYSICAL INACTIVATION: The virus is sensitive to temperatures above 58°C Footnote 21. Infectivity of factor VIII with virus is reduced with tri-N-butyl-phosphate (TNBP) and Tween 80, or heat treatment up to 30 hours at 60°C Footnote 22. Two heating cycles of 90 seconds at 103°C and 10 hours at 65°C may inactivate the virus during manufacture of a plasma-derived hepatitis-B vaccine Footnote 23.
SURVIVAL OUTSIDE HOST: Sindbis virus can infect and survive in cell culture at low temperature and low pH Footnote 24Footnote 25. It can also survive in various biological materials for long periods of time Footnote 22Footnote 23.
SURVEILLANCE: Monitor for symptoms. An IgM capture ELISA is available for the demonstration of virus-specific IgM antibody and is mostly used for the diagnosis. Patients may be screened for IgM with enzyme immunoassay and for total antibodies with the haemagglutination inhibition test Footnote 3. IgM may be detectable within the first 8 days of illness, and IgG within the first 11 days of illness Footnote 9. IgM increases during the acute phase of the disease and then tends to decrease slowly for 3 to 4 years, independent of persistent symptoms Footnote 10. The diagnosis is rarely made by virus isolation from blood but more frequently from vesicle fluid. A nested RT-PCR for species specific demonstration of virus is available Footnote 3Footnote 7.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Treatment is symptomatic. In cases of persistent arthritis, corticosteroids and acetylsalicylic acid are to be avoided, and diclofenac or other NSAID’s should be used instead Footnote 7.
IMMUNIZATION: None available to date Footnote 6.
PROPHYLAXIS: To avoid further transmission, protect patients from vectors (mosquitoes) Footnote 2.
LABORATORY-ACQUIRED INFECTIONS: None reported to date.
SOURCES/SPECIMENS: The virus can be isolated from infected mosquitoes Footnote 26, skin lesions and whole blood or serum samples of febrile patients Footnote 3Footnote 10. Sindbis virus can also be found in the central nervous system, blood, and liver of birds Footnote 7.
PRIMARY HAZARDS: Needlestick, and aerosols Footnote 27.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 27.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 27.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism before disposing by autoclave, chemical disinfection, gamma irradiation, or incineration.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: November 2011.
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright © Public Health Agency of Canada, 2011 Canada