Flaviviruses isolated from mosquitoes collected during the first recorded outbreak of Japanese encephalitis virus on Cape York Peninsula, Australia.

Abstract

Abstract. In response to an outbreak of Japanese encephalitis (JE) virus on Cape York Peninsula, Australia, in 1998, mosquitoes were collected using CO 2 and octenol-baited Centers for Disease Control and Prevention light traps. A total of 35,235 adult mosquitoes, comprising 31 species, were processed for virus isolation. No isolates of JE virus were recovered from these mosquitoes. However, 18 isolates of Kokobera virus, another flavivirus were obtained from Culex annulirostris. Twelve isolates were from western Cape York (minimum infection rate (MIR) of 0.61: 1,000 mosquitoes) and 6 were from the Northern Peninsula Area (MIR of 1.0:1,000). Potential explanations for the failure to detect JE virus in mosquitoes collected from Cape York Peninsula include the timing of collections, the presence of alternative bloodmeal hosts, differences in pig husbandry, asynchronous porcine seroconversion, and the presence of other flaviviruses.

Mosquito host‐feeding patterns and implications for Japanese encephalitis virus transmission in northern Australia and Papua New Guinea

“…The main ecological characteristics of both Cape York Peninsula and the Gulf Plains region of Australia were described by van den Hurk et al . (2001a, 2002).…”

“…The 1998 outbreak was geographically the most widespread, with virus activity spreading to the Northern Peninsula Area (NPA) and western Cape York Peninsula, resulting in the first reported case on mainland Australia (Hanna et al ., 1999). However, the outbreak on Cape York NPA was characterized by protracted seroconversion of the pigs and a failure to detect JE virus in mosquitoes, despite processing similar numbers to those collected from Badu Island where 43 isolates were obtained (Hanna et al ., 1999; Johansen et al ., 2001; van den Hurk et al ., 2001a). Furthermore, the results obtained from mosquito virus isolation studies and from sentinel pigs suggest that the virus has not yet become established in northern Australia (Hanna et al ., 1999; van den Hurk et al ., 2001a, 2002; A. T. Pyke, personal communication 2003).…”

Genetic divergence among members of the Kokobera group of flaviviruses supports their separation into distinct species

“…One such virus, New Mapoon virus (NMV), was isolated in 1998 from Culex annulirostris mosquitoes collected from the New Mapoon community on the tip of Cape York Peninsula, Queensland, Australia (Nisbet et al, 2005;Van Den Hurk et al, 2001). Partial sequence analysis and mAbbinding assays showed that this isolate was closely related to, but distinct from Kokobera virus (KOKV), which was first isolated in 1960 from C. annulirostris at Kowanyama (formerly Mitchell River Mission), approximately 530 km from the New Mapoon community (Doherty et al, 1963;Nisbet et al, 2005).…”

“…Acute polyarticular disease in humans has been attributed to KOKV (Boughton et Mein et al, 1998), and antibodies are common in people from Far North Queensland (Doherty et al, 1964;Hanna et al, 1999) and New South Wales (Hawkes et al, 1985(Hawkes et al, , 1993. KOKV has been isolated from mosquitoes in Northern Queensland and the Torres Strait (Doherty et al, 1979;Hanna et al, 1999;Johansen et al, 2003Johansen et al, , 2004, the Northern Territory (Standfast et al, 1984), Western Australia (Liehne et al, 1981;Poidinger et al, 2000;Van Den Hurk et al, 2001), New South Wales (Poidinger et al, 2000) and Papua New Guinea (Poidinger et al, 2000), and KOKV-specific neutralizing antibodies have been detected in serum from kangaroos and horses in central Queensland (Doherty et al, 1964).…”

Complete Coding Sequences of Three Members of the Kokobera Group of Flaviviruses

“…The prototype strain for this group, KOKV, was first isolated in 1960 in Mitchell River Mission in northern Queensland, Australia, from Culex annulirostris mosquitoes (2), and more recently from Sabai Island and Cape York Peninsula, Australia (3, 4). It has also been isolated in New South Wales and Western Australia (5) and the Northern Territory (6).…”