Effect of temperature and relative humidity on survival of eggs and infective larvae of Ostertagia circumcincta.
Survival of Ostertagia circumcincta eggs in faeces kept at 4 degrees C and of third stage larvae (L3) kept in distilled water at -50, -25, -10, 4, 16, 25 and 35 degrees C was studied. The effect of relative humidity (RH) of 95, 75, 50 and 30% at 16, 25 and 35 degrees C on the survival of L3 was also studied. The survival of eggs at 4 degrees C was high during the first week, followed by a gradual decline to 10% by Day 22 of storage. The L3 survived for 7 weeks at -50 degrees C, 9 weeks at -25 degrees C, 13 weeks at -10 degrees C, and 7 weeks at 35 degrees C. By 16 weeks, at the termination of the experiments, 74%, 76% and 23% of L3 were still alive at 4 degrees C, 16 degrees C and 25 degrees C, respectively. At all temperatures tested, the L3 survived longer at RH of 30 and 50% than at 75 and 95%. At 35 degrees C, L3 survived up to 6 weeks at 30%, 5 weeks at 50% and 1 week at 75 and 95% RH. At 16 and 25 degrees C and RH of 30 and 50%, over 70% of L3 were still alive at the end of experiments at the seventh week. At 25 degrees C, 40% of L3 survived for up to 5 weeks at 75% RH and 5% survived for 6 weeks at 95% RH.(ABSTRACT TRUNCATED AT 250 WORDS)
Pandey
V S
VS
Institute of Tropical Medicine, Antwerp, Belgium.
Chaer
A
A
Dakkak
A
A
D000818:Animals; D005243:Feces / Q000469:parasitology; D006813:Humidity; D007814:Larva / Q000254:growth & development; D010028:Ostertagia / Q000254:growth & development*; D010063:Ovum / Q000254:growth & development; D013696:Temperature; D013997:Time Factors