ABSTRACT
Biomphalaria glabrata and B. straminea were submitted to an out-door laboratory experiment for testing their comparative ability to resist desiccation. Results have shown that B. straminea is significantly higher resistant than B. glabrata. After five months under such distressing condition the survival ratios were: B. glabrata 8.1 per cent and B. straminea 18.4 per cent.
Subject(s)
Adaptation, Physiological , Biomphalaria/physiology , Animals , SeasonsABSTRACT
Experiments reported in the current paper, carried out under semi-field conditions created in the laboratory, have shown that B. straminea has competitive superiority when compared with B. glabrata. The former species has shown higher capabilities of both dispersal and vagility. In addition, B. straminea was able to compete successfully with B. glabrata.
Subject(s)
Biomphalaria , Competitive Behavior , AnimalsABSTRACT
Studies were carried out on two sugar estates in the humid coastal forest region of northeastern Brazil, a highly endemic area of schistosomiasis mansoni. Results obtained in a retrospective study were not conclusive, but clear-cut results emerged from a prospective study. The latter was conducted on a sugar estate (Catende) where the severe hepatosplenic clinical form of the disease is seen in 4% of the field-working population. Comparison was made between two groups of paired subjects: one composed of workers with the hepatosplenic form of the disease and the other composed of workers with the intestinal form. Reduction of productivity among the hepatosplenic subjects compared to intestinal subjects was 35.1%. The loss to the Catende sugar estate from reduced productivity caused by schistosomiasis mansoni for the harvest season of 1978 was calculated as 0.93% of the estate's total production, or approximately US$135,000. When this figure is extrapolated to the State of Pernambuco (16 million tons of sugar total annual production), the annual loss in the state if estimated to be US$2 million.
