Seasonal prevalence of the vector mosquitoes of Japanese encephalitis virus in Kyungpook Province, Korea

, Joo, Chong Yoon; , Wada, Yoshita

doi:1985.23.1.139

Korean J Parasito > Volume 23(1):1985 > Article

Original Article


Korean J Parasitol. 1985 Jun;23(1):139-150. English. Published online Mar 20, 1994. http://dx.doi.org/10.3347/kjp.1985.23.1.139
Copyright © 1985 by The Korean Society for Parasitology


Seasonal prevalence of the vector mosquitoes of Japanese encephalitis virus in Kyungpook Province, Korea
Chong Yoon Joo and Yoshita Wada
Department of Parasitology, Keimyung University School of Medicine, Taegu, Korea.
Department of Entomology, The National Institute of Health, Tokyo, Japan.


Abstract
In order to determine the seasonal prevalence and population density of vector mosquitoes in Kyungpook province, a survey based on average number of female mosquito per trap-night, were carried out during the period from May to November in 1984. Among the 34,571 mosquitoes collected in Kyungsan county in animal shelters and human dwellings by light traps, approximately 45.0 % were Culex tritaeniorhynchus, 34. 0 % per cent Culex pipiens pallens, and 19.0 per cent Anopheles sinensis. By comparison, distribution of mosquito species in Ankang town, in which Japanese encephalitis had been reported in the past, were quite different and A. sinensis was the most abundant species, being constituted in 75.8 per cent, followed by C. tritaeniorhynchus(23. 2 percent), and C. pipiens pallens(0. 6 per cent). In the general patten of seasonal prevalence, C. tritaeniorhynchus first appeared in mid-June, and trapped in large numbers during the periods from mid-August to early September, showing a simple sharply pointed one-peaked curve, while C. pipiens pallens was found to be active through almost the entire season showing irregular curves with several peaks. The trend of seasonal distribution of A. sinensis was similar to that of C. tritaeniorhynchus, but the earliest dates of appearance and disappearance different form that of C. tritaeniorhynchus. The results of hourly catches of mosquitoes by human baited traps have clearly shown the differences in the biting rhythm among the vector mosquitoes of this province, such as the facts that C. tritaeniorhynchus and A. sinensis are rather constantly active all through a night with more or less inconspicuous peaks twice a night, while C. pipiens pallens exhibits an irregular curve, and the numbers of A. vexans nipponii, C. vagans and Armigeres subalbatus are very small and are not sufficient for estimating the biting rhythm. Four genera and fourteen species of larval mosquitoes collected from eighteen kinds of habitats which classified according to the categories followed by Bates(1949). The main breeding sites contributing to peak C. tritaeniorhynchus adult densities in this surveyed areas were evidently ricefields, ground pools, puddles and swamps and marshes, etc. Summarizing the results, this study indicated that the highest population density of C. tritaeniorhynchus was encountered in late August and early September, showing simple sharply pointed one-peaked curve.

Figures


	Fig. 1 Surveyed areas in Kyungpook Province, Korea.


	Fig. 2 Fortnightly mean, maximum and minimum temperature, relative humidity and total rain fall(cm) reported by Regional Meteorological Centre in Taegu, Korea during 1984


	Fig. 3 Seasonal changes in the number of Culex tritaeniorhynchus collected by light traps in Kyungpook Province, Korea, 1984.


	Fig. 4 Seasonal prevalence of Culex pipiens pallens, Culex tritaeniorhynchus and Anopheles sinensis collected by light traps in 1984.


	Fig. 5 Biting rhythm of Culex tritaeniorhynchus and Anopheles sinensis as observed by the number of mosquitoes biting on human beings.

Tables


	Table 1 Species of mosquitoes identified in Kyungpook Province (1984)


	Table 2 Relative prevalence of various species of mosquitoes by light traps in two localities of Kyungpook Province, Korea (1984)


	Table 3 Number of the Culex tritaeniorhynchus collected by two light traps (1984)


	Table 4 Seasonal prevalence of three main mosquito species by the average numbers collected each decade with light traps in Kyungpook Province, Korea(1984), together with meteorological data


	Table 5 The results of overnight mosquito collections on human baits on two nights, July 17~18 and August 3~4, 1984 in Kyungpook Province (1984)


	Table 6 Hourly night catches of mosquifoes by light traps off cow baits, in two nights, July 17~18 and August 3~4, 1984 in Kyungpook Province (1984)


	Table 7 The reported average numver per trap-night of C. tritaeniorhynchus by month in Korea

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