Jayasekera N, Kalpage K S, De Silva C S
Department of Entomology, Medical Research Institute, Colombo, Sri Lanka.
Trans R Soc Trop Med Hyg. 1991 Mar-Apr;85(2):250-4. doi: 10.1016/0035-9203(91)90044-y.
Laboratory-bred Culex quinquefasciatus were fed on carriers with low and moderate densities of microfilariae (mf) of Wuchereria bancrofti. In the first series of experiments, mosquitoes were dissected 12 d after feeding. The percentage of infected mosquitoes and the numbers of larvae per infected mosquito were directly proportional to the mf density at the time of feeding. There was an overall high infection rate and a wide distribution of larvae per individual mosquito at all levels, except for the 4 lowest counts. Of the 4 carriers with counts of 5 mf/ml and less, 3 were capable of infecting Cx quinquefasciatus, giving infection rates of 1.0%, 7.4% and 12.0% respectively. In the second series, some mosquitoes were dissected immediately after feeding and the remainder 12 d later. There was a good correlation between the number of mf ingested and the number of infective larvae per mosquito. The high infection rates in Cx quinquefasciatus when fed on low-density microfilaraemia carriers, and the varying number of larvae in individual mosquitoes, suggest that low-density carriers could be a source of infection. Field studies were also carried out in 3 different area with mf rates of 7.24%, 0.72% and 0.16%, respectively. In the 2 areas with low mf rates, infection rates in mosquitoes were 1.32% and 1.08% respectively. Cx quinquefasciatus fed on a carrier with a residual microfilaraemia of 19 mf/ml following treatment with diethylcarbamazine had an infection rate of 13.8%. These studies suggest that the examination of recently fed house-resting populations of Cx quinquefasciatus could be a sensitive method for measuring the prevalence of mf in the human population.
用实验室饲养的致倦库蚊叮咬感染低密度和中等密度班氏吴策线虫微丝蚴的带虫者。在第一组实验中，在喂食后12天解剖蚊子。感染蚊子的百分比和每只感染蚊子体内幼虫的数量与喂食时微丝蚴的密度成正比。除了4个最低计数水平外，在所有水平上，总体感染率都很高，且每只蚊子体内幼虫的分布范围很广。在4个微丝蚴计数为5条/毫升及以下的带虫者中，有3个能够感染致倦库蚊，感染率分别为1.0%、7.4%和12.0%。在第二组实验中，一些蚊子在喂食后立即解剖，其余的在12天后解剖。摄入的微丝蚴数量与每只蚊子体内感染性幼虫的数量之间存在良好的相关性。致倦库蚊叮咬低密度微丝蚴血症带虫者时的高感染率，以及个体蚊子体内幼虫数量的差异，表明低密度带虫者可能是感染源。还在3个不同地区进行了现场研究，微丝蚴率分别为7.24%、0.72%和0.16%。在微丝蚴率较低的2个地区，蚊子的感染率分别为1.32%和1.08%。用乙胺嗪治疗后，致倦库蚊叮咬微丝蚴残留血症为19条/毫升的带虫者，感染率为13.8%。这些研究表明，检查近期进食后在室内休息的致倦库蚊群体可能是一种测量人群中微丝蚴流行率的灵敏方法。
