Publications

comparison of four species of snails as potential decoys to intercept schistosome miracidia.	preliminary studies have shown that various species of aquatic snails may be used as decoys or "sponges" to intercept schistosome miracidia, thereby preventing the miracidia from reaching the snails which normally serve as their intermediate host. in this study, four species of snails were evaluated as candidate decoys for field trials: marisa cornuarietis, pomacea australis, helisoma caribaeum, and tarebia granifera. in the laboratory all four species caused considerable reductions in the propo ...	1979	434319
bacterial flora of the schistosome vector snail biomphalaria glabrata.	the aerobic heterotrophic bacterial flora in over 200 individuals from 10 wild populations and 3 laboratory colonies of the schistosome vector snail biomphalaria glabrata was examined. internal bacterial densities were inversely proportional to snail size and were higher in stressed and laboratory-reared snails. the numerically predominant bacterial genera in individual snails included pseudomonas, acinetobacter, aeromonas, vibrio, and several members of the enterobacteriaceae. enterobacteriacea ...	1979	539821
[susceptibility of a strain of biomphalaria glabrata from venezuela to infection with 2 different strains of schistosoma mansoni].		1978	751168
biological control of biomphalaria glabrata in major reservoirs of puerto rico.		1977	907040
variations in infectivity for biomphalaria glabrata in strains of schistosoma mansoni from the same geographical area.	genetic differences in infectivity for intermediate snail hosts in two strains of s. mansoni from the same geographical area and within a single isolated parasite population are reported. the importance of recognizing the potential for such genetic variation is stressed.	1976	1088517
genetic factors in susceptibility of biomphalaria glabrata for different strains of schistosoma mansoni.	biomphalaria glabrata selected for genetic differences in susceptibility to infection with a puerto rican strain of schistosoma mansoni were exposed to miracidia of a strain of s. mansoni from st lucia. the st lucian strain was less infective than the puerto rican. results suggested that in snails susceptible to the puerto rican s. mansoni differences in susceptibility to the st lucian straing were determined by a single gene, with insusceptibility dominant.	1975	1128925
[experimental schistosomiases. i. study of s. mansoni fecondity as regards to its adaptation to different biomphalaria glabrata strains (author's transl)].	we compared the infestation of different strains of b. glabrata from brasil (recife). guadeloupe, martinique and porto-rico with 6 to 8 miracidia of s. mansoni (from recife. we noted the four following points: 1. the planorbid snails from martinique and guadeloupe had a low resistance to infestation. 2. the guadeloupean snails showed the lesser rate of positivity and the lower medium amount of emitted cercaries but, in the four strains of snails, the level of the issued cercaries is quite the sa ...	1975	1221915
the genetic variation of compatibility in biomphalaria glabrata and schistosoma mansoni.	interactions between different biomphalaria glabrata stocks and schistosoma mansoni strains were studied. a series of inbred stocks of b. glabrata were characterized as to genetic variations in susceptibility at different ages to a series of different s. mansoni strains. a series of inbred strains of s. mansoni were characterized as to genetic variations in infectivity for b. glabrata stocks at different ages. also described is a process of selection for substrains from a single s. mansoni isola ...	1987	3437352
effect of marisa cornuarietis on populations of biomphalaria glabrata in farm ponds of puerto rico.		1973	4688423
ribeiroia marini: pathogenesis and larval trematode antagonism in the snail, biomphalaria glabrata.		1973	4706118
susceptibility of adult biomphalaria glabrata to schistosoma mansoni infection.		1973	4745234
evaluation of two methods for the detection of schistosoma mansoni cercariae shed by biomphalaria glabrata.		1971	5105897
biological control of biomphalaria glabrata by marisa cornuarietis in irrigation ponds in puerto rico.		1969	5308710
control of schistosomiasis in guayama and arroyo, puerto rico.	in 1953, a programme to control schistosomiasis mansoni was started in guayama and arroyo, puerto rico, employing, first, chemical and, later, both biological and chemical methods to control biomphalaria glabrata, the snail host of schistosoma mansoni. sodium pentachlorophenate was the molluscicide, and an ampullarid snail, marisa cornuarietis, was used for biological control in ponds and reservoirs. in addition some chemotherapy was given to infected persons. the prevalence of intestinal schist ...	1970	5309511
cost of harvesting and spreading marisa cormuarietis for biological control of biomphalaria glabrata in aibonito, puerto rico.		1970	5309516
control of biomphalaria glabrata in a small reservoir by fluctuation of the water level.		1970	5493051
population structure in biomphalaria glabrata: examination of an hypothesis for the patchy distribution of susceptibility to schistosomes.	it has been suggested that the patchy distribution of snail susceptibility to schistosomes might be due to genetic drift. since direct estimation of genes for susceptibility is not feasible in population studies, electrophoretic techniques were used to examine this hypothesis for populations of biomphalaria glabrata from puerto rico. these populations were characterized by relative genetic homogeneity within populations and differentiation among local populations. the data presented are consiste ...	1982	7149103
the boqueron project after 5 years: a prospective community-based study of infection with schistosoma mansoni in puerto rico.	the boqueron schistosomiasis project is a prospective community-based study of schistosoma mansoni infection after the interruption of transmission by nonchemotherapeutic control measures. the study methods and the parasitologic results of the first five annual stool surveys are described in this report. in the first year, 1972, among 904 inhabitants (88% of the total population) the prevalence of infection was 40%, and the geometric mean intensity of infection among positives was 16.1 eggs per ...	1980	7446813
studies on host-parasite relationship between the puerto rican strain of schistosoma mansoni and biomphalaria snails.	immunoelectrophoretic studies on common antigenicities were carried out by using rabbits sera immunized with the puerto rican strain of schistosoma mansoni adult worms or eggs and antigens of several adult biomphalaria snails and vice versa. as the result, s. mansoni adult worm extracts produced 8 bands both with extracts of biomphalaria glabrata pigmentation and b. glabrata pigmentado, 3 to 4 bands with those of b. glabrata albino and 1 to 2 bands with those of b. straminea. on the other hand, ...	1994	7777917
human schistosomiasis in puerto rico: reduced prevalence rate and absence of biomphalaria glabrata.	a combined epidemiologic and malacologic survey of schistosomiasis in puerto rico was carried out in areas where previous surveys had reported the prevalence of the disease. this limited survey, with 495 persons examined, found a low prevalence (0.6%) of schistosoma mansoni infections. the infections were restricted to three people more than 36 years of age. no infections were detected in children 16 years of age or less, and this cohort comprised 57.8% of the study group. malacologic surveys of ...	1997	9392596
comparative studies for development of schistosoma mansoni sporocysts in puerto rican and brazilian biomphalaria glabrata.	the development of sporocysts of schistosoma mansoni was monitored in pigmented and albino biomphalaria glabrata from puerto rico and brazil. the snails were exposed individually to 20 miracidia, and sporocysts were allowed to develop for 3 to 12 weeks. most of the immature sporocysts were found in the seminal receptacle sac and vas deferens during development. in contrast, mature daughter sporocysts were detected everywhere except in the foot at 12 weeks after exposure to the miracidia. it was ...	2000	11043519
mixed strain schistosome infections of snails and the evolution of parasite virulence.	mathematical models often propose that within-host competition between parasites can be a major factor in the evolution of increased parasite virulence. kin selection predicts that as the coefficient of relatedness between infecting parasites decreases, the benefits of competition to individual genotypes increases. thus where parasites can adjust their behaviour in response to current conditions, higher virulence is predicted in multiple genotype infections. there is limited experimental data, h ...	2002	11811801
molluscicidal activity of plants from puerto rico.	overall, 173 tropical plants from 72 different families, collected from the north-western and western regions of puerto rico, were screened for their molluscicidal properties against biomphalaria glabrata, the intermediate host of schistosoma mansoni. six plant extracts were effective at 50 ppm. the two most effective extracts were those from the leaves of didymopanax morototoni (araliaceae) and mammea americana (guttiferae), which, at 50 ppm, killed all snails after 24 h of exposure and a day f ...	2002	12080983
in vitro cultivation of cells from ovotestis tissue of pigmented biomphalaria glabrata.	cells derived from ovotestis tissue of pigmented biomphalaria glabrata, puerto rican strain were cultured in double diluted git medium supplemented with modification of amino acids components of pigmented b. glabrata, ovotestis and mid-gut region and 3% inactivated fetal calf serum. as a result, two types of cells, epithelial and fibroblastic like cells increased in number during the cultivation. it seem that the medium used in this study is a suitable medium for cultivation of cells from ovotes ...	2002	12125924
intraspecific competition and the evolution of virulence in a parasitic trematode.	intrahost competition between parasite genotypes has been predicted to be an important force shaping parasite ecology and evolution and has been extensively cited as a mechanism for the evolution of increased parasite virulence. however, empirical evidence demonstrating the existence and nature of intraspecific competition is lacking for many parasites. here, we compared within-host competitiveness between genetic strains of schistosoma mansoni with high (high-v) or low (low-v) virulence to thei ...	2005	15856697
surface morphology and characteristics of hemocytes of biomphalaria glabrata (pulmonata: planorbidae) from two geographic sources.	biomphalaria glabrata is a fresh water snail of medical importance since it is the intermediate host of the trematode schistosoma mansoni. the internal defense system of mollusks is mostly represented by circulating elements of the hemolymph (hemocytes). the infectivity of s. mansoni to b. glabrata is determined by genetic factors and evolutionary adaptations. in the present work factors about the parasite/snail relationship were evaluated, especially those related to the morphology and characte ...	2001	17061496