RESUMEN
Experimental studies about the recovery, survival and migration to pasture of cyathostomin infective larvae (L(3)) from fresh feces depositions were conducted from February 2005 to March 2007 in a tropical region of southeast Brazil. Grass and feces were collected weekly at 8 a.m., 1 and 5 p.m. and processed by the Baermann technique. Multivariate analysis (principal components method) showed the influence of time and environmental variables on the number of infective larvae recovered from the feces and pasture. In the rainy period (October-March), more infective larvae were recovered on the feces and grass apex. In contrast, in the dry period (April-September), the recovery was higher only on the grass base, as well as the L(3) survival on feces and grass. More larvae were recovered at 8 a.m., except from the grass apex, where the highest recovery was at 1 p.m. Few studies investigating the seasonal transmission of equine cyathostomin have been conducted in South American tropical climates. These results demonstrate that in tropical conditions L(3) are available on feces and pasture throughout the year. Knowledge of climatic influences on the development and survival of L(3) is crucial to designing integrated parasite control programs that provide effective protection while slowing the development of anthelmintic resistance.
Asunto(s)
Ecosistema , Enfermedades de los Caballos/parasitología , Nematodos/fisiología , Infecciones por Nematodos/veterinaria , Animales , Brasil/epidemiología , Heces/parasitología , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/parasitología , Enfermedades Gastrointestinales/veterinaria , Enfermedades de los Caballos/epidemiología , Caballos , Larva/fisiología , Infecciones por Nematodos/epidemiología , Infecciones por Nematodos/parasitología , Poaceae/parasitología , Factores de Tiempo , Clima TropicalRESUMEN
Vinte e três espécies de nematóides estrongilídeos (18 Cyathostominae e cinco Strongylidae) foram coletadas de alíquotas, com aproximadamente, 10 por ciento do cólon dorsal de 33 eqüinos, provenientes da região de Janeiro. Cylicostephanus Longibursatus (90,9 por ciento; 1.078,4) C. goldi (81,8 por ciento; 236,9) e Cylicocyclus nassatus (75,8 por ciento; 39,1) foram as espécies mais prevalentes e com maior abundância média, respectivamente. Cylicostephanus longibur-satus apresentou o maior Ïndice de Dispersão (2.524.1) e menor Índice de Green (0,1), devido á presenca em quase todas as infracomunidades, e ao baixo nível de agregacã dos espécimes nas mesmas. Cinco infracomunidades (2, 3, 11, 24 e 25) apresentaram riqueza parasitária igual a quatro, porém os índice de Shannon e de uniformadade de Pielou foram distintos, devido á equitabilidade das infrapopulacões