Host-feeding patterns and behaviour of 4 Culex species in an endemic area of Japanese encephalitis

Studies were made on the host-feeding patterns and behaviour of 4 Culex species in China (Province of Taiwan) to further assess their importance as vectors of Japanese encephalitis. A relatively unbiased, non-attractant technique (vacuum sweep-net) was used for collecting mosquitos resting outdoors on rural premises; blood meals from engorged specimens were identified by precipitin tests. Additional information was obtained by analysing data from related studies. Precipitin-test results indicated that C. annulus, C. tritaeniorhynchus, and C. fuscocephalus feed principally on mammals, the first species mainly on swine and the latter two largely on bovine hosts. Mosquito forage ratios suggested that the apparent preference of C. annulus for swine over bovine hosts might be a function of host density. C. annulus was found to be zoophilic, exophilic, and exophagic; however, in view of its abundance during the JE epidemic season, contact with human hosts may reach a significant level, even indoors. The other 3 species of Culex were considered to be of lesser importance as JE vectors during the 1971 epidemic season because of their host-feeding patterns and/or population densities.