Fate of developing larvae of Onchocerca lienalis and O.volvulus in micropore chambers implanted into laboratory hosts

Abstract

Infective larvae of Onchocerca lienalis and O.volvulus implanted subcutaneously within micropore chambers into laboratory hosts moulted to the fourth stage (L4) and underwent limited development and growth. Similar recoveries of O. lienalis L4 larvae in the range of 33–66% were obtained from chambers implanted into CBA and BALB/c strains of mice, jirds, and the natural bovine host. A relatively constant proportion of larvae survived up to 24 days post implantation and thereafter recoveries declined, although some worms were still alive after 96 days. Recoveries of O. volvulus L4 larvae from chambers given to normal or T-cell deprived mice were equivalent to one another and to those obtained with O. lienalis. Moulting of O. lienalis in chambers was observed on days 3 and 5, in close accordance with the timing of the third moult in cattle following systemic infection. Moulting of O. volvulus occurred between days 3–6. Morphological changes in developing larvae included a small but significant increase in length, a transient increase in width, and early development of the spicular primordia and genital tube. L4 larvae of O. lienalis, but not those of O. volvulus, exhibited 3 distinct caudal papillae not present on infective larvae.

New features on the moults and morphogenesis of the human filariaLoa loaby using rodent hosts. Consequences

“…The first data is thought to be the most reliable. It is similar to that of O. lienalis for which all the authors agree (Bianco & Muller, 1982;Lok et al, 1984 b;Bianco et al, 1989).…”

“…Taken together, they could well illuminate real relationships. The group presenting an early moult 3 includes two genera, which are respectively the types of the Diro filariinae and Onchocercinae subfamilies: Dirofilaria, of which D. immitis is the only cycle elucidated, and Onchocerca, with two elucidated cycles, O. lienalis (Bianco & Muller, 1982;Bianco et al, 1989) and O. volvulus (Bianco et al, 1989). As far as we know, moult 4 has not been determined in Onchocerca spp.…”

“…The eight Orihel, 1961Kotani & Powers, 1982Lichtenfels et al, 1985Sawyer & Weinstein, 1965Sawyer & Weinstein, 1965Lok et al, 1984Lichtenfels et ai, 1985 Bianco & Muller. 1982Lok et al, 1984Bianco et al, 1989 0.5…”

Resistance and Susceptibility to Filarial InfectionwithLitomosoides sigmodontisAre Associated with EarlyDifferences in Parasite Development and in Localized ImmuneReactions

“…From our observations, which suggest that the immunological or genetic status of the host does not significantly affect early recovery, we predict that a similar proportion of larvae will develop in individuals residing in areas where filariae are endemic, including those considered putatively immune. Therefore, a stage older than the infective larvae may be the main target of protective immune responses in humans, given the rapid molting (2 to 3 days) of the filarial L3 larvae of the genus Onchocerca to stage 4 (9,11).…”

Immune responses to filarial infection in laboratory mice

“…injection of L3 of B. malayi [15][16][17], or s.c. compared to i.p. injection of L3 of closely related B. pahangi [18,19], a natural feline and canine parasite; and (b) s.c. implantation of diffusion chambers containing O. volvulus [20,21] or O. lienalis [20,22] L3; the reason for using such chambers is to restrict the spread of the L3 for easier recovery. Since B. malayi and B. pahangi L3 can be maintained in the laboratory by cyclic passage through Aedes aegypti mosquitoes and the permissive jirds, L3 are obtained rather conveniently by dissection of the mosquitoes 14 days after a blood meal on the microfilaremic rodent [16][17][18]; in addition, A. aegypti mosquitoes harbouring Brugia L3 are commercially available [23].…”