The effect of Brugia pahangi infection on survival of susceptible and refractory species of the Aedes scutellaris complex. 1987

M S Ibrahim, and M Trpis
Department of Immunology and Infectious Diseases, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205.

Life table statistics were used to examine the survival functions of filarial susceptible and refractory species of the Aedes scutellaris (Walker) group of mosquitoes, following infection with high and moderate doses of Brugia pahangi (Buckley & Edeson). Survivorship curves and hazard function curves were generated, and the median survival times and the proportions of mosquitoes surviving beyond the extrinsic incubation period of the parasite were determined. In the susceptible populations of Aedes polynesiensis Marks, Ae. pseudoscutellaris (Theobald) and Ae.tabu Ramalingam & Belkin a dose-response relationship was detected between parasite load and mortality. This relationship was characterized by a significant reduction in the proportions of infected female mosquitoes surviving at days 1 and 9 postinfection, reduction in the median survival times and an increase in the hazard rates as the infectious dose increased. The survival of the refractory species, Ae.alcasidi Huang and Ae.katherinensis Woodhill was not significantly affected by the infection. A positive correlation between microfilaraemia in the vertebrate host and parasite load in the susceptible mosquito populations was also observed. Regression analysis of the number of parasites recovered from susceptible mosquitoes at the time of death showed that mosquitoes at highest risk of dying harboured from 11.6 to 19.4 infective larvae when fed on a gerbil with sixty-five microfilariae per 20 microliters blood; this resulted in 34.4-40.2% mortality by day 9 postinfection. A mean number of 32.6-46.9 infective larvae was observed when these populations were exposed to a gerbil with a microfilaraemia of 150 mf/20 microliters and resulted in 72.8% to 80% mortality in these populations. Viable infective larvae were recovered from infected mosquitoes up to 50 days postinfection.

UI MeSH Term Description Entries
D008297 Male Males
D012044 Regression Analysis Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable. Regression Diagnostics,Statistical Regression,Analysis, Regression,Analyses, Regression,Diagnostics, Regression,Regression Analyses,Regression, Statistical,Regressions, Statistical,Statistical Regressions
D002009 Brugia A filarial worm of Southeast Asia, producing filariasis and elephantiasis in various mammals including man. It was formerly included in the genus WUCHERERIA. Brugias
D005260 Female Females
D005849 Gerbillinae A subfamily of the Muridae consisting of several genera including Gerbillus, Rhombomys, Tatera, Meriones, and Psammomys. Gerbils,Jird,Meriones,Psammomys,Rats, Sand,Gerbil,Jirds,Merione,Rat, Sand,Sand Rat,Sand Rats
D000330 Aedes A genus of mosquitoes (CULICIDAE) frequently found in tropical and subtropical regions. YELLOW FEVER and DENGUE are two of the diseases that can be transmitted by species of this genus. Aede
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D015993 Life Tables Summarizing techniques used to describe the pattern of mortality and survival in populations. These methods can be applied to the study not only of death, but also of any defined endpoint such as the onset of disease or the occurrence of disease complications. Life Table Analysis,Life Table Methods,Life Table Models,Life Table Estimates,Life Table Method,Analyses, Life Table,Analysis, Life Table,Estimate, Life Table,Estimates, Life Table,Life Table,Life Table Analyses,Life Table Estimate,Life Table Model,Method, Life Table,Methods, Life Table,Model, Life Table,Models, Life Table,Tables, Life

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