PubMed Health⌕ Search

Biomedical subjects

J P Pointier

Publications and source records attributed to J P Pointier.

44 records · Page 3Linked to original sources
PubMed1976

Study of growth of Biomphalaria glabrata Say and other Planorbidae in Guadeloupe West Indies.

The growth of Biomphalaria glabrata, B. schrammi, Drepanotrema lucidum and D. kermatoides was studied in three habitatis on Guadeloupe. Theortical growth curves were calculated for each species by applying the Walford method and the von Bertalanffy equation. On Guadeloupe, the growth of B. glabrata was faster in the ponds of Grand Terre than in the small high altitude streams of Basse Terre. There is good correlation between the observations made in Guadeloupe and previous data obtained on Pureto Rico and St Lucia.

Animals↗
PubMedDate not supplied

[Influence of some medium factors on the fecundity of Biomphalaria glabrata (Say, 1818) Mollusca, Pulmonata) in laboratory conditions].

In different samples of fresh waters we studied the fecundity of Biomphalaria glabrata. We tested, too, the influence of different concentrations of Na, Ca, Mg, and K-salts. The snail, B. glabrata, is not affected by very high rates of those salts but eggs laying is getting down when the amount of NaCl is between 2000 and 4000 mg/1, of MgCl2 between 410 and 763 mg/1 and KCl between 330 and 760 mg/1. The rate in Ca seems inactive in the field of fecundity but, in an other hand, high concentrations of Ca suppressed the inhibiting effect of the high rates in Mg. B. glabrata is not affected by high rates in Mg, when Mg/Ca is Low. The inhibiting effect of Mg begins when Mg/Ca is around 30. The importance of different kinds of substratum for eggs lying on fecundity was also studied.

Animals↗
PubMedDate not supplied

[Intestinal schistosomiasis in the freshwater mangrove of Guadalupe (French Antilles). Ecology of the vector, Biomphalaria glabrata and its parasite Schistosoma mansoni (author's transl)].

In the freshwater mangrove of Dubelloy-Devarieux (Guadalupe), the dynamics of populations of B. glabrata and the transmission of S. mansoni, mostly depends on the alternation of dry and rainy season. The flooding of the mangrove (in september), permits a yearly renewal of the malacological populations. The sizes analysis of the snails shows that the life cycle of B. glabrata include two rainy seasons separated by one dry season. The prevalence of B. glabrata (0,25%) and cercariae densities (0,8 c/l) are very slow. The acrophase of the rhythm of presence in standing waters is reached at 2 pm. Men and rats are infected. The infections of rats is of 20% at the beginning of the rainy season and of 100% at the end of the rainy season. Principal factors involved in the infection of rats are discussed.

Animals↗
PubMedDate not supplied

[Evaluation of a trial to control Biomphalaria glabrata in Guadeloupe by using a sterilizing trematode (author's transl)].

A trial of biological control of Biomphalaria glabrata was carried out in Guadeloupe by using Ribeiroia marini guadeloupensis Nassi, 1978, an autochtonal Trematode which sterilizes the snail vector of Schistosoma mansoni. The trial took place in a pond in which the population of B. glabrata presents an annual demographic cycle related to the alternation of dry and rainy seasons. About 8 millions eggs of R. marini were introduced in 15 months into the biotope. Despite the low yield of these introductions, due particularly to the high turbidity of the water, this trial gave positive results in the disappearance of almost all the snails. The analysis of the results concerning the evolution of the levels of the snails and of the prevalence shows that a comparable efficiency could be obtained by massive introductions of eggs during short periods.

Animals↗
PubMedDate not supplied

[An ecological approach to the problem of the responsibility of men and rats in the workings of a transmission site of Schistosoma mansoni in Guadeloupe (Western Indies) (author's transl)].

The study of the rate of contamination of B. glabrata and the cercarial densities of S. mansoni in the chanels of Beaugendre valley (Guadeloupe, French West Indies) concentrates attention on the focalisation of the sites with high risk of contamination. This focalization of the sites of transmission is directly related to the regular deposition of human faeces. A small number of contamined people is enough to maintain high cercarial densities (230 c/1). In the chanel studied, the role of the rat in the transmission of the parasite seems less important than that of the Man. The infection of the rats during consumption of snails can be foreseen.

Animals↗
PubMedDate not supplied

[Principal factors involved in the settlement of Biomphalaria glabrata (Say, 1818), snail intermediate host of schistosomiasis in Guadalupe (author's transl)].

Six biotopes of Biomphalaria glabrata, the snail intermediate host of schistosomiasis in Guadalupe, were investigated during one annual cycle. These six biotopes included a pond, a freshwater mangrove, a stream, a mountain lake, a "microhabitat" and a canal. These six types of biotopes were characterized by various parameters whose fluctuations reveal the main factors regulating the B. glabrata populations. The climatic factors are essential in Grande Terre and resulted in an annual development cycle well determined of all the aquatic communities. The biotic factors (Predation, competition, parasitism) are important in every type of biotope, in Grande Terre as well as in Guadalupe proper. In every type of biotope, anthropic factors are also important, but mainly in canal nets which are the principal focus of human schistosomiasis. The chemical factors themselves are less important.

Animals↗
PubMedDate not supplied

[Factors responsible for cercarial concentration of schistosoma mansoni in Guadeloupe].

Research carried out in Guadeloupe on the sites of transmission of Schistosoma mansoni shows that the circadian evolution of the cercarial concentration (rhythm of presence) differs slightly according to the biotope:--in a running water habitat (greater than 0,10 m/s) the rhythm of presence is superimposed on the rhythm of emergence, which leads to a risk of contamination reaching a maximum between 11 a.m. and noon; --in a slow running water habitat (around 0,01 m/s), the acrophase of the rhythm of presence is clearly retarded in comparison with that of the rhythm of emergence. In this case, the risk of contamination is greatest between 2 p.m. and 5 p.m. because of the accumulation of cercariae. The absolute value of the cercarial concentration in running water results from two antagonistic processes: production of cercariae depending on the amount of Biomphalaria glabrata infected and dilution of cercariae depending on the flow rate of water. Thus along one channel the cercarial concentration shows great variation depending upon which of the above processes predominates. These results demonstrate that the risk of human contamination can never be directly deduced from the demography of vectors.

Animals↗