Public health priority: Urgent.
PHU response time: Respond to confirmed cases within a day of notification. Enter confirmed cases on NCIMS within one working day.
Case management: Determine possible exposures.
Contact management: Nil
The national surveillance case definition has been updated and is available at: West Nile/Kunjin virus infection Australian national case definition.
Kunjin virus cases are to be notified by laboratories on diagnosis (ideal reporting by telephone within 1 hour of diagnosis). Only confirmed cases should be entered onto NCIMS.
Kunjin virus is one of the arboviruses (arthropod borne viruses known to be pathogenic for humans). Kunjin virus is a member of the genus Flavivirus, in the family Flaviviridae (Dengue fever, Japanese encephalitis, Murray Valley Encephalitis, Zika, Kokobera, Stratford, Alfuy and Edge Hill are also flaviviruses). It is very closely related to the West Nile virus (WNV).
Kunjin virus is transmitted by the bite of an infected mosquito, primarily Culex species. There is no evidence of direct person-to-person spread.
The incubation period is unknown but thought to range from 5 to 26 days.
Symptoms are variable, but typically include sudden onset of fever, anorexia and headache. Vomiting, nausea, diarrhoea, muscle aches and dizziness may also occur. Neurological dysfunction may be experienced with photophobia, lethargy, irritability, drowsiness, neck stiffness, confusion, ataxia, aphasia, intention tremor, convulsions, coma and death. Encephalitis following infection with Kunjin is probably rare.
Sentinel chickens in the NSW arbovirus surveillance program occasionally seroconvert to Kunjin in the western part of the State, with the most recent seroconversions in 2011. Cases of human infection with Kunjin are very rare, although one case was reported in 2012.
On same day of notification of a confirmed case follow-up investigation and notify the CDB of the case details
Within one working day of notification enter confirmed cases on NCIMS. Cases of WNV acquired overseas should be entered as Kunjin - overseas acquired with travel history included.
The response to a notification will normally be carried out in collaboration with the case's health carers. But regardless of who does the follow-up, PHU staff should ensure that action has been taken to:
Supportive treatment only.
The case or relevant care-giver should be informed about the nature of the infection and the mode of transmission.
The case should be asked to recall if, in the incubation period, he or she had:
Infected people should be protected from further mosquito exposure (staying indoors in areas with screens or under a mosquito net) during the first few days of the illness, so they do not contribute to the transmission cycle.
Disease occurrence may indicate the need for extraordinary mosquito investigation and control measures and other environmental management strategies and/or health information for the community. This should be discussed with NSW Health Department's Centre for Health Protection.
Potentially exposed people are those who may have been exposed to the same source as the case. However, active searching for these people is not usually indicated.
Educate the public living in or travelling to endemic areas to minimise exposure to mosquito bites. Information should indicate geographical location of habitats, and periods of maximum mosquito activity and also refer to protective clothing, appropriate repellents and methods of reducing mosquitoes in the home. Factsheets are available.