Environmental factors influencing the transmission of Haemonchus contortus

摘要: Abstract Infection with the gastrointestinal nematode Haemonchus contortus causes considerable losses in sheep industry. In this study, we evaluated effect that climate has on third-stage larvae (L3) of H. terms their migration from feces to Brachiaria decumbens grass, as well distribution among forage plants. Fecal samples containing L3 was deposited soil herbage at an initial height 30 cm. Sample collection began 24 h after contamination and performed alternate days over 13 days. The were recovered quantified three strata (heights) grass (0–10 cm, 10–20 cm >20 cm) remaining a superficial layer soil, collected beneath feces. order obtain results under different environmental conditions, fecal pasture January (summer), April (autumn), July (winter). all periods, able migrate herbage. However, rains, accompanied by high relative humidity temperatures, apparently favored migration. highest recovery rate summer observation period, which had number measurable precipitation, (>68.2%), temperatures level (minimum maximum means 19 °C 42 °C, respectively). Under those reach upper stratum (>20 cm) deposition matter, having reached peaking seven deposition. autumn there no rainfall first five post-contamination. During numbers found demonstrating can act reservoir absence rain. Except for two when most tops blades where located predominantly base conclusion, favors addition, larval up along occur relatively rapidly temperature is high.