Isolation of Japanese encephalitis virus from mosquitoes (Diptera: Culicidae) collected in the Western Province of Papua New Guinea, 1997-1998.

Abstract

After Japanese encephalitis (JE) virus emerged in the Torres Strait in Australia in 1995, investigations were initiated into the origin of the incursion. New Guinea was considered the most likely source, given its proximity to islands of the Torres Strait. Almost 400,000 adult mosquitoes were processed for virus isolation from 26 locations in the Western Province of Papua New Guinea (PNG) between February 1996 and February 1998, yielding three isolates of JE virus. Two isolates of Murray Valley encephalitis, 17 isolates of Sindbis, and 1 each of Sepik and Ross River viruses were also obtained. Nucleic acid sequences of the PNG JE isolates were determined in the prM region, and in a region overlapping a part of the fifth nonstructural protein and the 3' untranslated region. The PNG isolates belonged to genotype II, and shared > 99.2% identity with isolates from humans and mosquitoes from the Torres Strait, suggesting that PNG is the source of incursions of JE virus into Australia.

Contribution of Dengue Fever to the Burden of Acute Febrile Illnesses in Papua New Guinea: An Age-Specific Prospective Study

“…There has only been one other case of JE identified in humans in PNG, but there is evidence of its presence in mosquito populations. 31,32 The clinical features of acute DF episodes in our cohort were not specific, and we did not observe the typical clinical picture of rash, eye pain, headache, and fever. In our study, dengue was mostly an undifferentiated febrile illness, which is confirmed by the multivariate analysis; it was unable, however, to identify clinical predictors of dengue cases compared with non-dengue/non-malaria cases, except facial flushing and sex (male).…”

Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends

“…Regarding St. Louis encephalitis virus in North America, local persistence in southern regions of the United States rather than annual introduction has become a shared view among some professionals. On the other hand, in northern Australia, a genotyping study provided a supporting evidence of repeated southward invasions of JEV from Papua New Guinea (143).…”

High-Resolution Metatranscriptomics Reveals the Ecological Dynamics of Mosquito-Associated RNA Viruses in Western Australia

“…Furthermore, a number of the viruses discovered here were found not only in Western Australia but also in regional countries like China and Indonesia, indicating that they infect hosts over a wide geographical area. As the viruses present in these different countries are very similar (95% to ϳ98% nucleotide identities), such limited genetic distance tentatively suggests that these viruses were introduced by windblown mosquitoes (36,37) or by cyclones from neighboring regions (38) or were inadvertently spread by humans, rather than the result of ancient mosquito dispersal. Conversely, based on current data, there appears to be relatively little overlap between the mosquito viromes sampled from Western Australia and those sampled from other parts of Australia (3,10), which may reflect the different mosquito species present in these localities.…”