The effect of parent generation stress on infectivity of Oesophagostomum dentatum new population
2001
Talvik, H. (Estonian Agricultural Univ., Tartu (Estonia). Faculty of Veterinary Medicine) | Christensen, C.-M.
Environmental conditions, such as temperature and humidity, are of great importance for the development of infective stage larvae and their infectivity. However, besides this, conditions inside the host may have more epidemiological importance than hitherto believed. It is of theoretical as well as of practical importance to study the possible changes in development and infectivity of eggs and larvae of stressed worm populations. We examined the impact of different Oesophagostomum dentatum dose levels and durations of infection on development and infectivity of the following generations. Pigs were trickle-infected with 200, 2000 or 20,000 L3/week during 20 weeks. Egg hatch assays (EHA) were performed at monthly intervals; however, no consistent differences were found between any of the dose groups in the development of eggs into first stage larvae. To compare larval infectivity, larvae were derived from faecal cultures set up from the low and the high dose groups in the early and the late part of the experiment, and were inoculated into helminth-free pigs. Worm recoveries were significantly higher (P0.05) in the group of pigs receiving larvae derived early in the experiment from the low dose group than the two groups receiving larvae from high dose groups, thus indicating an adverse effect of high doses of trickle infection on the later infectivity of L3 larvae derived from excreted eggs
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