Lok J B, Cupp E W, Bernardo M J
Am J Vet Res. 1983 Dec;44(12):2355-8.
Biting flies were collected from the umbilical areas of Onchocerca lienalis-infected cattle in New York (state) from June through September of 1980. Of the 766 flies collected, 705 were Simulium jenningsi. Microfilariae were detected in the midguts of 37 (50%) of 73 females dissected immediately after the flies had fed. The mean number of larvae per positive fly (fly with microfilariae) was 15.2. Third-stage larvae were recovered from 25 (21.9%) of 114 S jenningsi dissected 8 to 13 days after they had fed on the infected cattle; the mean number of 3rd-stage larvae per positive fly was 3.5. Dissections of flies performed on days 1 through 7 after feeding yielded various numbers of 1st and 2nd-stage larvae from the thoracic muscles. Ovarian dissections performed on 304 S jenningsi attacking cattle indicated an overall parous rate of 58%. Naturally occurring infections with filarial larvae indistinguishable from O lienalis were found in 7.3% of the parous females. Three of these flies, or 1.7% of the parous collection, harbored 3rd-stage larvae. The onset of naturally occurring filarial infections in the population of S jenningsi coincided with a peak in the parous rate in late June. Thereafter, filarial infections were generally detected when the parous rate was above 50%.
1980年6月至9月，从纽约州感染盘尾丝虫的牛的脐部采集叮咬蝇。在采集的766只蝇中，705只是詹氏蚋。在73只进食后立即解剖的雌蝇中，有37只（50%）的中肠检测到微丝蚴。每只阳性蝇（带有微丝蚴的蝇）的幼虫平均数为15.2。在114只詹氏蚋进食感染牛8至13天后解剖，从其中25只（21.9%）中回收了第三期幼虫；每只阳性蝇的第三期幼虫平均数为3.5。进食后第1至7天对蝇进行解剖，从胸肌中获得了不同数量的第一期和第二期幼虫。对304只叮咬牛的詹氏蚋进行卵巢解剖，结果显示总体产蚴率为58%。在7.3%的产蚴雌蝇中发现了与盘尾丝虫难以区分的丝虫幼虫自然感染。其中三只蝇，即产蚴蝇样本的1.7%，体内含有第三期幼虫。詹氏蚋种群中自然发生的丝虫感染开始时间与6月下旬产蚴率的峰值一致。此后，通常在产蚴率高于50%时检测到丝虫感染。
