Biomphalaria tenagophila: dynamics of populations of resistant and susceptible strains to Schistosoma mansoni, with or without pressure of the parasite.
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.
Rosa
Florence Mara
FM
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horzonte, MG, Brazil.
Godard
Ana Lúcia Brunialti
AL
Negrão-Correa
Deborah
D
Rodrigues
Horácio Antonio
HA
Carvalho
Omar Dos Santos
Odos S
Caldeira
Roberta Lima
RL
Teles
Horácio Manoel Santana
HM
Maciel
Engels
E
Jannotti-Passos
Liana Konovaloff
LK
Coelho
Paulo Marcos Zech
PM
D000818:Animals; D001700:Biomphalaria / Q000235:genetics* / Q000469:parasitology; D001947:Breeding / Q000379:methods*; D003433:Crosses, Genetic; D004199:Disease Vectors; D005799:Genes, Dominant / Q000235:genetics*; D006790:Host-Parasite Interactions / Q000235:genetics; D011157:Population Dynamics; D012550:Schistosoma mansoni / Q000502:physiology*