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Vector survival and parasite infection: the effect of Wuchereria bancrofti on its vector Culex quinquefasciatus

  • K. KRISHNAMOORTHY (a1), S. SUBRAMANIAN (a1), G. J. VAN OORTMARSSEN (a2), J. D. F. HABBEMA (a2) and P. K. DAS (a1)...
Abstract

This paper investigates a cohort of 2187 laboratory reared Culex quinquefasciatus fed on 69 human volunteers, including 59 persons with different levels of Wuchereria bancrofti microfilariae and 10 without microfilaria. Mosquitoes were followed until death. Mosquito survival was analysed in relation to the level of microfilaria in the human and larval count in the dead mosquito. Vector mortality during the extrinsic incubation period (12 days post-engorgement) was significantly higher in mosquitoes fed on microfilaraemic volunteers (50%) than in those fed on amicrofilaraemics (29%). Both the percentage infected and the geometric mean parasite density was significantly higher among mosquitoes which died before 13 days (45% infected and 10 larvae per infected mosquito) than those surviving beyond 13 days (39% and 2·2), suggesting a parasite loss of more than 80% during the extrinsic incubation period. A large proportion (62%) of the mosquitoes that died during the early of phase of parasite development were infected (36% in low, 26% in medium and 90% in high human Mf-density). Survival analysis showed that the parasite load in mosquitoes and the human Mf-density for a given parasite load are independent risk factors of vector survival. Overall, the hazard of dying was found to be 11–15 times higher among mosquitoes fed on microfilaraemic volunteers than those fed on amicrofilaraemics. The hazard doubles for every increase of about 60–70 parasites in the vector. As a consequence of the parasite-induced reduction in vector survival, the transmission success of the parasite is reduced. The implication of the results on control/elimination of lymphatic filariasis using mass-drug administration is discussed.

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Corresponding author
Vector Control Research Centre (Indian Council of Medical Research), Indira Nagar, Medical Complex, Pondicherry-605 006, India. Tel: +91 413 2272396/2272397. Fax: +91 413 2272041. E-mail: vcrc@vsnl.com
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BASANEZ, M. G., TOWNSON, H., WILLIAMS, J. R., FRONTADO, H., VILLAMIZAR, N. J. & ANDERSON, R. M. ( 1996). Density-dependent processes in the transmission of human onchocerciasis: relation between microfilarial intake and mortality in the simuliid vector. Parasitology113, 331355.

BRYAN, J. H. & SOUTHGATE, B. A. ( 1988). Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 2. Damage to ingested microfilarie by mosquito foregut armatures and development of filarial larvae in mosquitoes. Transactions of the Royal Society of Tropical Medicine and Hygiene82, 138145.

COLLETT, D. ( 1994). Modelling Survival Data in Medical Research. Chapman and Hall, Madras.

CRANS, W. J. ( 1973). Experimental infection of Anopheles gambiae and Culex pipiens fatigans with Wuchereria bancrofti in coastal East Africa. Journal of Medical Entomology10, 189193.

DAS, P. K., SUBRAMANIAN, S., MANOHARAN, A., RAMAIAH, K. D., VANAMAIL, P., GRENFELL, B. T., BUNDY, D. A. P. & MICHAEL, E. ( 1995). Frequency distribution of Wuchereria bancrofti infection in the vector host in relation to human host: evidence for density dependence. Acta Tropica60, 159165.

DYE, C. & WILLIAMS, B. G. ( 1995). Non-linearities in the dynamics of indirectly-transmitted infections (or, does having a vector make a difference?). In Ecology of Infectious Diseases in Natural Populations ( ed. Grenfell, B. T. & Dobson, A. P.), pp. 260279. Cambridge University Press, Publications of the Newton Institute, Cambridge.

FAILLOUX, A. B., RAYMOND, M., UNG, A., GLAZIOU, P., MARTIN, P. M. V. & PASTEUR, A. ( 1995). Variation in the vector competence of Aedes polynesiensis for Wuchereria bancrofti. Parasitology111, 1929.

JAYASEKERA, N., KALPAGE, K. S. & DE SILVA, C. S. ( 1991). The significance of low density microfilaraemia in the transmission of Wuchereria bancrofti by Culex (Culex) quinquefasciatus Say in Sri Lanka. Transactions of the Royal Society of Tropical Medicine and Hygiene85, 250254.

JORDAN, P. & GOATLY, K. D. ( 1962). Bancroftian filariasis in Tanganyika: a quantitative study of the uptake, fate and development of microfilariae of Wuchereria bancrofti in Culex fatigans. Annals of Tropical Medicine Parasitology56, 173187.

MAEDA, R. & KURIHARA, T. ( 1980). The effect of age of Aedes togoi on the transmission of Brugia malayi in the laboratory. Japanese Journal of Sanitary Zoology31, 277281.

McGREEVY, P. B., BRYAN, J. H., OOTHUMAN, P. & KOLSTRUP, N. ( 1978). The lethal effects of the cibarial and pharyngeal armatures of mosquitoes on microfilariae. Transactions of the Royal Society of Tropical Medicine and Hygiene72, 361368.

NATHAN, M. B. ( 1981). Bancroftian filariasis in coastal North Trinidad, West Indies: intensity of transmission by Culex quinquefasciatus. Transactions of the Royal Society of Tropical Medicine and Hygiene75, 721730.

OTTESEN, E. A. & RAMACHANDRAN, C. P. ( 1995). Lymphatic filariasis infection and disease: control strategies. Parasitology Today11, 129131.

SAMARAWICKREMA, W. A. & LAURENCE, B. R. ( 1978). Loss of filarial larvae in a natural mosquito population. Annals of Tropical Medicine and Parasitology72, 561565.

SAPORU, F. W. ( 1993). Analysis of survival data for Simulium damnosum using the regression method. Annals of Tropical Medicine and Parasitology87, 563569.

SUBRAMANIAN, S., KRISHNAMOORTHY, K., RAMAIAH, K. D., HABBEMA, J. D. F., DAS, P. K. & PLAISIER, A. P. ( 1998). The relationship between microfilarial load in the human host and uptake and development of Wuchereria bancrofti microfilariae by Culex quinquefasciatus: a study under natural conditions. Parasitology116, 243255.

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Parasitology
  • ISSN: 0031-1820
  • EISSN: 1469-8161
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