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The effects of Onchocerca lienalis infection on vitellogenesis in the British blackfly, Simulium ornatum

  • M. Renshaw (a1) and H. Hurd (a1)


We have previously described the major yolk protein, vitellin, in the British blackfly Simulium ornatum Meigen. Here we demonstrate that vitellogenin, synthesized in the fat body and secreted into the haemolymph, is composed of subunits with the same approximate molecular weight as vitellin, namely 200 and 68 kDa. Simulium ornatum is the natural vector for the cattle filarial nematode Onchocerca lienalis Stiles, which induces host fecundity depletion. A significant reduction in ovarian vitellin content was associated with infection by intrathoracic injection of 20 O. lienalis microfilariae immediately after blood-feeding. Fat body synthesis of vitellogenin was significantly reduced as early as 8 h post-infection in comparison with sham-injected flies. When total haemolymph protein from infected and sham injected flies was compared, titres were significantly depressed 6 h post-infection. However, later in the infection, titres were elevated by 30%, the major component being vitellogenin. The injection of dead microfilariae had no effect. An infection burden of a single parasite caused a significant reduction in ovarian protein content in comparison with shams, but no further significant decrease was observed as the parasite burden was increased from 5 to 20. Possible mechanisms underlying the disturbance of Simulium reproductive physiology are proposed.



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Bianco, A. E., Ham, P. J., El Sinnary, K. & Nelson, G. S. (1980). Large scale recovery of Onchocerca microfilariae from naturally infected cattle and horses. Transactions of the Royal Society of Tropical Medicine and Hygiene 74, 109.
Cheke, R. A., Garms, R. & Kerner, M. (1982). The fecundity of Simulium damnosum s.l. in northern Togo and infections with Onchocerca spp. Annals of Tropical Medicine and Parasitology 54, 561–8.
Clements, A. N. (1992). The Biology of Mosquitoes, Vol. 1. London: Chapman and Hall.
Hacker, C. S. (1971). The differential effect of Plasmodium gallinaceum on the fecundity of several strains of Aedes aegypti. Journal of Invertebrate Pathology 18, 373–7.
Ham, P. J. (1992). Immunity in haematophagous insect vectors of parasitic infection. Advances in Disease Vector Research 9, 101–49.
Ham, P. J. & Banya, A. J. (1984). The effect of experimental Onchocerca infections on the fecundity and oviposition of laboratory reared Simulium spp. (Diptera: Simuliidae). Tropenmedizin und Parasitologie 35, 61–6.
Ham, P. J. & Gale, C. L. (1984). Bloodmeal enhanced Onchocerca development and its correlation with fecundity in laboratory reared blackflies (Diptera: Simuliidae). Tropenmedizin und Parasitologie 35, 212–16.
Ham, P. J., Townson, S., James, E. R. & Bianco, A. E. (1981). An improved technique for the cryopreservation of Onchocerca microfilariae. Parasitology 83, 139–46.
Harlow, E. & Lane, D. P. (1988). Antibodies: A Laboratory Manual. Cold Spring Harbor, New York: Cold Spring Harbor Laboratory.
Hays, A. R. & Raikhel, A. S. (1990). A novel protein produced by the vitellogenic fat body and accumulated in mosquito oocytes. Roux's Archives of Developmental Biology 199, 114–21.
Hurd, H. (1990). Physiological and behavioural interactions between parasites and invertebrate hosts. Advances in Parasitology, Vol. 29 (ed. Baker, J. R. & Muller, R.), pp. 272318. London: Academic Press.
Hurd, H. (1993). Reproductive disturbances induced by parasites and pathogens in insects. In Parasites and Pathogens of Insects (ed. Beckage, N. E., Thompson, S. N. & Federici, B. A.), pp. 87105. Orlando: Academic Press.
Hurd, H. & Arme, C. (1986). Hymenolepis diminuta: influence of metacestodes on synthesis and secretion of fat body protein and its ovarian sequestration in the intermediate host, Tenebrio molitor. Parasitology 93, 111–20.
Hurd, H. & Arme, C. (1987). Hymenolepis diminuta: effect of infection upon the patency of the follicular epithelium in the intermediate host, Tenebrio molitor. Journal of Invertebrate Pathology 49, 227–34.
Javadian, E. & Macdonald, W. W. (1974). The effect of infection with Brugia pahangi and Dirofilaria repens on the egg production of Aedes aegypti. Annals of Tropical Medicine and Parasitology 68, 477–81.
Raikhel, A. S. (1992). Vitellogenesis in mosquitoes. Advances in Disease Vector Research 9, 139. New York: Springer-Verlag.
Renshaw, M. & Hurd, H. (1994). Vitellogenin sequestration by Simulium oocytes: the effect of Onchocerca infection. Physiological Entomology 19, 70–4.


The effects of Onchocerca lienalis infection on vitellogenesis in the British blackfly, Simulium ornatum

  • M. Renshaw (a1) and H. Hurd (a1)


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