Entry of Filaria Larvae into the Body Cavity of the Mosquito

Abstract

The commonly accepted view regarding the manner of entry of larvae of Wuchereria bancrofti (Cobb.) into the body cavity of its mosquito host is that microfilariae from human blood enter the stomach of the mosquito along with the blood meal and after casting their sheath in the stomach, they penetrate through the wall of the stomach, enter the haemocele and then find their way into the thoracic muscles. The time taken for the penetration of the stomach wall according to Looss (1914) is 6–12 hours. According to Bahr (1912) the worms appear in the thoracic muscles in 24 hours, while Lebredo (1905) recorded that in exceptional cases, worms were seen in the thorax 13 hours after feeding, but ordinarily the time interval was longer.

The Behaviour and Development of Brugia patei (Buckley, Nelson and Heisch, 1958) in a Mosquito Host, Mansonia uniformis (Theobald)

“…1). This is accomplished, as Iyengar (1936) observed, within 2 hours of the blood meal. Lavoipierre (1958b) has reviewed the literature on the penetration of microfilariae from the gut of the arthropod host and concludes that penetration of the gut wall is usually prolonged over many hours.…”

“…There is a conflict of opinion as to the route of migration of the microfilariae of Brugia in Mansonia and, also, the rapidity with which they migrate from the blood meal into the thorax of the mosquito. Iyengar (1936) found the microfilariae of B. malayi in the cardiac (thoracic) part of the stomach of M. annulifera and concluded from the rapidity with which the microfilariae penetrated into the thoracic flight muscles, within two hours, that migration from the gut into the flight muscles took place through the wall of the cardiac stomach directly into the thorax. Wharton (1957a) found no microfilariae in the cardiac portion of the stomach of M. longipalpis, but found numbers in the stomach and, after 10 minutes, in the abdomen and in the thorax.…”

“…Microfilariae that have penetrated the indirect flight muscles have straightened between the muscle fibres, although the posterior end still shows some sinuosity (Iyengar, 1936). Migrating forms in the thorax show considerable sinuosity and these have been found amongst fat body cells, the heart and amongst the leg muscles near the side of the thorax, from 15 to 190 minutes after engorgement.…”

The invasion of the midgut of the mosquito Culex (Culex) quinquefasciatus Say, 1823 by the helminth Litomosoides chagasfilhoi

“…Previous studies (Iyengar, 1936;Beatty, 1936, 1938;Schrater et al, 1982;Oda and Wada, 1980;Fuhrman and Piessens, 1985;Fuhrman et al, 1987;Bryan and Southgate, 1988a,b;Bryan et al, 1990 andNayar andKnight, 1995) showing microWlariae exsheathment before Fig. 5.…”

“…O'Connor and Beatty (1936) and Iyengar (1936) have previously suggested the peritrophic matrix as an eYcient barrier for microWlaria migration towards the midgut, by studying the interaction of W. bancrofti and B. pahangi microWlariae with M. annulifera and Culex fatigans, respectively. Afterwards, a number of studies have conWrmed the PM as an important barrier for microWlariae invasion of the midgut.…”