. Animal parasites and human disease. Parasites; Medical parasitology; Insects as carriers of disease. CONTROL OF TABAXIDS 489 only by men who spend the day in the forest, and is most prevalent in May and June, a time corresponding to the appearance of many tabanids, points strongly to these insects as the carriers of the infection, since they are the only diurnal insects exclusively found in forest regions. The forest leishmaniasis of Paraguay may also be due to tabanids. In one other case a tabanid is implicated in the spread of a disease. In the tropical jungles of Africa certain species of
. Animal parasites and human disease. Parasites; Medical parasitology; Insects as carriers of disease. CONTROL OF TABAXIDS 489 only by men who spend the day in the forest, and is most prevalent in May and June, a time corresponding to the appearance of many tabanids, points strongly to these insects as the carriers of the infection, since they are the only diurnal insects exclusively found in forest regions. The forest leishmaniasis of Paraguay may also be due to tabanids. In one other case a tabanid is implicated in the spread of a disease. In the tropical jungles of Africa certain species of Chrysops locally known as mangrove flies, serve as in- termediate hosts for filarial worms. Leiper and other investigators have found that the larvae of the loa worm, Loa loa, which swarm in the peripheral blood of the host in the daytime only, undergo rapid development in Sev- Fig. 227. A deerfly, Chrysops callidus. eral Chrysops, especially C. dimidiata and C. silacea (see p. 309). It has recently been shown by Francis that tularemia, a rodent disease of western United States, caused by Bacterium tularense, and transmissible to man, may be transmitted, and probably commonly is, by the deerfly, Chrysops discalis. These flies are infective from a few seconds to at least fourteen days after biting an infective rabbit. Control. — Prevention of bites from tabanids, especially dur- ing an epidemic of anthrax, or where diseases believed to be transmitted by tabanids are prevalent, is important. Practi- cally the only means that can be employed is the use of repellents, as for other insect pests (see p. 455). According to Herms, re- pellents efficient against tabanids usually contain fish oil. In a recent publication , a Russian entomologist, having found that tabanids have the peculiar habit of skimming over pools, touching the lower side of their bodies to the surface, advised the conversion of such pools into traps by pouring oil on them to produce a surface film, s
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