ABSTRACT
Six lots of 18 B. glabrata from: La victoria, Turmero, Cagua in Aragua state; Caserío El 25 in Carabobo state, Chabasquén in Portuguesa state and Humocaro Bajo in Lara state, were experimentally infected withmiracidia of SM, C5 and C6 strains of Schistosoma mansoni (18 snails/Schistosoma mansoni strain). The averages od the intramolluscal period (IMP) obtained for the S. mansoni strains were very similar and comprised between 35.4 and 36.1 days. No significative statistical differences in the IMP were found according to the S. mansoni strains and the size of snails:<7 mm and >7 mm. However, significative statistical differences in the IMP were found, in relation to the B. glabrata strain and between the snails classifiel in two groups according to the S. mansoni dose (miracidia/snail and 10 miracidia/snail). The higher percentages of infection (PI) were found for the following parasite-snail) combinations: C6-Cas. El 25 (80.7 percent), SM-La Victoria (73.1 percent) and C5-Cagua (62 percent). No significative statistical differences were found for the PI a) between the snail classifiel in two groups according to the size (<7 mm and > 7 mm), b) in relation to the miracidium dosification (5 and 10 miracidia/ snail and c) in accord to the S. mansoni strain. However, significative statistical differences were found for the PI obtained with different strains of the snail
Subject(s)
Animals , Biomphalaria/parasitology , Schistosoma mansoni/pathogenicity , Biomphalaria/anatomy & histology , Host-Parasite Interactions , Schistosoma mansoni/physiology , VenezuelaABSTRACT
Se infectaron experimentalmente 9 lotes de 32 caracoles B. glabrata (de 5 a 7mm de diámetro) con miracidios de la cepa C5 de Schistosoma mansoni a razón de 5 miracidios por caracol, pertenecientes a las siguientes cepas: En el área endémica de transmisión de Esquistosomiasis mansoni a) Sector Puerta Negra, Lago Valencia, b) Cagua c) Ingenio Bolívar (Estado Aragua) d) Mariara e) Caserío El 25 f) Güigüe (Estado Carabobo). Fuera del área endémica de transmisión g) Anzoátegui (Estado Lara), h) Chabasquén (Estado Potuguesa), i) Sector La Elvira, Caripe (Estado Monagas). El período prepatente intramolusco, osciló entre 23 y 25 días, para las 9 cepas evaluadas. La duración total de la infección fue muy variable desde 20 días para la cepa Chabasquén, hasta 93 días para la de Güigüe. La producción total promedio de cercarias al tercer día de iniciada la emisión varió desde X = 74,4 para la cepa de Mariara, hasta X = 591,7 para la cepa de Chabasquén. Se evidenció la existencia de diferencias estadísticamente significativas (H = 97,4, P < 0,05) en la producción total de cercarias al tercer día de iniciada la emisión, detectándose diferencias estadísticamente significativas para casi todas las 36 combinaciones, excepto para las cuatro siguientes: Mariara/lngenio Bolívar, Cagua/Caserío El 25, Lago de Valencia/Güigüe y Güigüe/Caripe. En lo que respecta al porcentaje de caracoles que presentaron cura espontánea, los valores mas elevados se obtuvieron en las cepas del Lago de Valencia (88,8 por cento), Cagua (85,2 por cento), Chabasquén (82,6 por cento), Caripe (82,6 por cento0) y Anzoátegui (80 por cento). Mientras que el porcentaje mas bajo se obtuvo para la cepa de Güigüe (21,4 por cento)
Subject(s)
Animals , Biomphalaria/parasitology , In Vitro Techniques , Schistosoma mansoni/physiology , Host-Parasite Interactions , Schistosoma mansoni/pathogenicity , Schistosomiasis mansoni/parasitology , VenezuelaABSTRACT
Mediante la impregnación con nitrato de plata, de un lote de 47 cercarias de la cepa C5 de Schistosoma mansoni (Venezuela), se evidenció un polimorfismo de tallas. El morfo estaría conformado por las cercarias mas grandes (entre 152,9 y 218µm), este grupo siempre presente en la población de cercarias en menor porcentaje (29,8 por cento). El grupo constituido por las cercarias de talla normal, menores de 152,8µm es dominante en la población de cercarias (70,2 por cento). La comparación entre el largo de ambos lotes de cercarias resultó con diferencias estadísticamente significativas (t = 5,5; P < 0,001). Para el total de las cercarias estudiadas, el largo promedio del cuerpo cercariano resultó de 143,9µm y el ancho de 68,6µm. Se detectó una correlación positiva y significativa entre el ancho y el largo de las cercarias de 1 a cepa objeto de estudio (r = 0, 83; P < 0, 00 1)
Subject(s)
Animals , Polymorphism, Genetic , Schistosoma mansoni/classification , Snails , Biometry , Sex FactorsABSTRACT
By means of Kato-Katz technique 113,254 coprological samples of the human population belonging to 100 counties from Venezuela were analyzed. It was determined the following prevalences: ascaris lumbricoides 26,8 percent, trichuris trichiura 32,7 percent and hookworm 5,6 percent. It was found a strong correlation between a. lumbricoides and t. trichiura infection (p<0,001), a significant correlation between t. trichiura and hookworn (p<0,5) and no correlation between a. lumbricoides and hookworm
Subject(s)
Humans , Infant , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Helminthiasis/epidemiology , Prevalence , Age Distribution , Ancylostoma/isolation & purification , Ascaris lumbricoides/isolation & purification , Feces/parasitology , Housing , Necator americanus/isolation & purification , Parasite Egg Count , Soil Microbiology , Trichuris/isolation & purificationABSTRACT
By means of the silver impregnation of two lots of Schistosoma mansoni cercariae belonging to the strains: JR (32 cercariae) and C5 (45 cercariac), the number and pattem of disposition of the argentophillic papillae were detertnined with the following results: -Average number of total dorsal papillae: 12.1 (JR strain) and 12.0 (C5 strain); the variation coefficients in this surface were less than 4 por ciento (JR strain) and bigger in JR than C5 strain. -Average number of total ventral papillac: 12.15 (JR), 11.97 (C5); maximum value of the variation coeficiente 6.4 por ciento (JR), higher in JR than C5 strain. -When the ventral surface was classified in four quadrants, the average number of papillae by quadrant was: quadrant A: 1. 15 (JR) and 1.06 (C5); B: 1.06 (JR) and 1 (C5); C: 4.97 (JR) and 4.96 (C5); D: 5.03 (JR) and 4.98 (C5). The variation coefficients were higher in the A and B ventral quadrants, reaching maximum values of 31.9 por ciento, and 61.0 por ciento for the posterior quadrants C and D. -When the ventral surface was divided in three equal parts for determining the position of the most variable papillae of this area, the greatest value of the variation coefficients obtained were for the 2nd thirds of the cercariae: 89.8 por ciento and 76.8 por ciento for C5 strain and 43.5 por ciento and 56.8 por ciento for JR strain. In relation to the total lateral papillac, the average numbers were: 17.0 (JR) and 16.6 (C5), with a maximum value of variation coefficient of (8. 1 por ciento (C5). The average total numbers of papillae of the tail were: 25.6 (JR) and 26.1 (C5) for the ventral surface and 20.72 (JR) and 21.33 (C5) for the dorsal papillae. The comparison between the percents of the cercariae of two S. mansoni strains with more than 1 papillae on the anterior ventral quadrants A or B (94 por ciento JR and 34 percent C5), resulted with significant diferentes (P < 0.05) (AU)##