Long-term controlled field experiment on the competition between two species of Biomphalaria (Mollusca, Basommatophora), the snail vectors of Schistosoma mansoni in Northeastern Brazil

Abstract

A long-term controlled field experiment on the interactions of the populations of Biomphalaria glabrata (target population) and B. straminea (competitor) was carried out in the county of Alhandra, state of Paraíba, Brazil, during the period 1980 through 1989. Results obtained in the current paper show that the snail B. straminea has strong competitive advantages over B. glabrata. In six out of nine streams the native population of B. glabrata were totally excluded and replaced by B. straminea. There is evidence showing that seasonal dryness has marked influence on the phenomenon studied in this paper. In all the streams were B. straminea already predominated, return of B. glabrata was never observed.

Study of the snail intermediate hosts for Schistosoma mansoni on Itamaracá Island in northeast Brazil: spatial displacement of Biomphalaria glabrata by Biomphalaria straminea

“…Over a 3-year period, Barbosa (1973) observed that autochthonous B. glabrata snails being displaced by invasive B. straminea ones in a locality in the metropolitan region of Recife, Pernambuco, suggesting the possibility that competitive displacement was taking place. In 1992, the same author followed up this phenomenon between the two species by means of laboratory experiments (Barbosa et al, 1992) and in 1993, the competitive capacity of B. straminea to replace B. glabrata was induced and confirmed under experimental field conditions (Barbosa et al, 1993). This observation confirmed what was stated by Michelson and Dubois (1979) that the competitive capacity of B. straminea, in comparison with B. glabrata, highlighting its higher reproductive rate and capacity to invade territories.…”

Predicting frequency distribution and influence of sociodemographic and behavioral risk factors of Schistosoma mansoni infection and analysis of co-infection with intestinal parasites

“…Previous malacological studies by our group in this area have showed that the irrigation system impacts on the competitive selection replacing the native Biomphalaria straminea by B. glabrata (Barboza et al, 2012) which is more sensitive to dehydration and therefore favored by the irrigation system (Michelson and Dubois, 1979;Barbosa et al, 1993). B. glabrata is more easily infected by S. mansoni and this is probable one of factors influencing schistosomiasis transmission in this area (Barboza et al, 2012).…”

The bioecology of snail vectors for schitosomiasis in Brazil

“…The three populations studied by Barbosa et al (1992), exhibited a "snail crude density" that was significantly different in each population: the two strains of B. straminea displayed clear advantages over B. glabrata when bred under identical conditions, especially the R3 strain, which has been used in investigations on snail biological competition in the Northeast of Brazil (Barbosa et al, 1993). Conditions.…”