Tee microfilariae in a man's blood, however, had to be sucked up by the: proper kind of mesquite, otherwise they merely died off in' the blood stream. The bite of an infected mos-quite was the only way one could et the disease of Alarlasis, so that by controlling the mosquitoes capable of carrying the worms one could control the spread of the disease.
Dr. Hu then described how the eptibility of the various species mosquitoes was tested, "wrigglers" of tke different types being reared the laboratory and allowed to bite man who was q Marlal case and had volunteered his services. Fourteen days of incubation was allowed for. the Mlarial worms to complete their development in the infected mosquitoes, after which each species fof mosquito was dissected, and the! results of the experiment noted.
As a result, it was found that they could not develop in most of the Tocal species. In some, the embryo worms died soon after they wore {aken up; such was the case with the ite black mosquito with white spots, called the "tiger mosquito," which, he reminded his listeners, usually bites us during the day time in summer. In the ease of the big black Ipesgutoes which visited one during tke autumn months, the fanal worms Filarlasis was caused by parasitic worms, known sclentiically touchereia, bancroft, which" were about three inches long and lived in the Iymphatle system of man when fully grown. They occasionally caused fa blockage in this region, when arms, Jegs, and other parts of the human body "became swollen considerably. Tels disease was known as elephantiasis.
The fillarial worms gave birth millions of embryos, called—mlero-Alarioe, which were released into the blood stream and infected a mosquito when it bit 2 filarial subject. A Mlarial subject, Incidentally, often contained over 200 mierofllariae in a single drop of blood. This type of person was quite common around Shanghai, 181 per cent. of the prisoners in the town of Paoshan, for Instance, being found to show these embryo worms in their blood. Most of the flarfal cases locally, however, id not show any marked symptoms.
Microfilarlae Fad the peculiar habit of coming to the vessels of the skin only at night, disappearing into the Internal parts of the body daring the day; Just why this was had yet to be discovered. Hence a mosquito which bit an infected subject st night was more likely to be in turn infected.
After the proper type of mosqilto had sucked up a number of mlcro-Mlariae with its little meal of blood, }these worms penetrated its stomach walls and lodged in the muscle fibres only developed half way, and then died.
The Best Carriers Unfortunately, it was found that the best carrier of filariasis was the common spedes of house mosquito known as culex piptens, which were he little brown fellows that pester use In our houses and on our lawn at night all through the mosquito season." This species was abundant due to Its reediness to breed wherever there was stagnant and polluted water, and In some of the Institute's experiments, over 90 per cent. of the criles pipiens which had bitten the flarlat case were found to have fully, developed infective Marisl worms when dissected.
'As an example of how quickly this species became infected, Dr. Hu mentioned that mosquitoes' of this type were collected from the laundry of Tungehl University, Woosung. on. several mornings: six workers, two of whom were filarial cases, lived there. When 245 of these mosquitoes were dissected and examined, they found that 42, or 17 per cent. were infected with Maris! worms. As many as 75 infective filarial worms were found in a single mosquito. Concluding on a warning note, Dr.
said that asthe infective filarial parasites could remain alive for over months in the infected eulez pipiens mosquito, one could readily see that they were rather dangerous 1s carriers of Blariasis, Herald" Photo,
Text read from the printed page and cleaned; old type leaves the occasional error.