Biomphalaria tenagophila: dynamics of populations of resistant and susceptible strains to Schistosoma mansoni, with or without pressure of the parasite

• Published in: Memórias do Instituto Oswaldo Cruz Vol. 101 Suppl 1; no. suppl 1; pp. 247 - 251
• Main Authors: Rosa, Florence Mara, Godard, Ana Lúcia Brunialti, Negrão-Correa, Deborah, Rodrigues, Horácio Antonio, Carvalho, Omar Dos Santos, Caldeira, Roberta Lima, Teles, Horácio Manoel Santana, Maciel, Engels, Jannotti-Passos, Liana Konovaloff, Coelho, Paulo Marcos Zech
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil Instituto Oswaldo Cruz, Ministério da Saúde 01.10.2006; Fundação Oswaldo Cruz (FIOCRUZ)
• Subjects: Animals; Biomphalaria - genetics; Biomphalaria - parasitology; Biomphalaria tenagophila; Breeding - methods; Crosses, Genetic; Disease Vectors; dynamics of populations; Genes, Dominant - genetics; Host-Parasite Interactions - genetics; PARASITOLOGY; Population Dynamics; resistant and susceptible strains; Schistosoma mansoni; Schistosoma mansoni - physiology; TROPICAL MEDICINE; Schistosoma mansoni; Biomphalaria tenagophila; resistant and susceptible strains; dynamics of populations
• ISSN: 0074-0276; 1678-8060; 1678-8060; 0074-0276
• DOI: 10.1590/S0074-02762006000900038

Resistant (Taim, RS) and susceptible albino (Joinville, SC) Biomphalaria tenagophila populations were kept together, at different proportions, throughout a 18-month-period. Some of the snail groups were submitted to Schistosoma mansoni infection. The targets of this study were (a) to analyze the populational dynamics among resistant and susceptible individuals to S. mansoni; (b) to study the resistance phenotype in descendants of cross-breeding; (c) to observe whether the parasite could exert any kind of selection in those snail populations. Throughout the experiment it could be observed that the susceptible B. tenagophila strain (Joinville) underwent a selective pressure of the parasite that was negative, since the individuals showed a high mortality rate. Although B. tenagophila (Taim) population presented a higher mortality rate without pressure of the parasite, this event was compensated by a reproductive capacity. B. tenagophila Taim was more fecund than B. tenagophila Joinville and was able to transmit the resistance character to their descendants. F1 generation obtained by cross-breeding between resistant and susceptible lineages was completely resistant to S. mansoni infection, irrespective of the Taim proportion. Moreover, less than 5% of F2 progeny were susceptible to S. mansoni infection.