Premium
Pairing Probability of Schistosomes Related to Their Distribution Among the Host Population
Author(s) -
Morand Serge,
Pointier Jean-Pierre,
Borel Gaetan,
Theron Andre
Publication year - 1993
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1939595
Subject(s) - biology , host (biology) , population , parasite hosting , schistosoma , helminths , schistosoma mansoni , pairing , schistosomiasis , ecology , zoology , parasitism , sex ratio , distribution (mathematics) , demography , physics , superconductivity , quantum mechanics , sociology , world wide web , computer science , mathematical analysis , mathematics
Schistosomes are dioecious blood helminth parasites of mammals, including humans, and are responsible for schistosomiasis in tropical countries. The distribution patterns of worms among their host populations and the pairing probabilities of female schistosomes are of considerable importance in understanding transmission dynamics of this parasite. Data were obtained from field studies carried out over 8 yr on natural populations of Schistosoma mansoni, a human parasite but heavily infecting rats (Rattus rattus) in Guadeloupe. The distribution of male and female worms within the whole host population was fitted to a negative binomial, and the aggregation coefficient was estimated. The observed prevalence of male—female pairs, the observed prevalence of worms, and the observed pairing probability were calculated. Results demonstrate a strongly clumped worm distribution. Observed pairing probabilities of female worms in cases where male and female schistosomes are aggregated together within the host population are of the same order (@A o b s ranging from 0.83 to 0.97) as the expected values obtained with the May (1977) model but significantly higher than in cases where the sexes are aggregated separately. A disequilibrated sex ratio biased towards male schistosomes increases the pairing probabilities of female worms.