Survival of Eggs and Larvae of Swine Nematode Parasites in Aerobic and Anaerobic Waste Treatment Systems

Abstract

AbstractExperiments were conducted at 12 and 22°C to compare the effects of aerobic and anaerobic treatment systems on the development and survival of eggs and larvae of swine nematode parasites. Swine feces containing eggs of Ascaris suum, Metastrongylus spp., Oesophagostomum dentatum, Hyostrongylus rubidus, and Strongyloides ransomi were used in both experiments. Treatment system fluids were sampled and examined periodically for the presence of parasite eggs and larvae. Cultures of fluids were prepared and examined for the presence of larvae after 7 days of incubation at 25°C. Ascaris eggs embryonated in 28 days in the 22°C aerobic system. Unembryonated Ascaris eggs in the other three treatment systems completed their development when transferred to 2% formalin at 25°C. Metastrongylus eggs survived in all treatment systems, but some larvae hatched and died in both aerobic systems. Oesophagostomum and Hyostrongylus larvae survived well under 12°C aerobic conditions, but were destroyed within 11 days at 22°C. Eggs of Strongyloides hatched rapidly under aerobic conditions, but survived at least 7 days under anaerobic conditions in both experiments. The development of free‐living adults of Strongyloides and the survival of third‐stage larvae were favored in 22°C aerobic conditions. Knowledge of the parasite genera present in a swine herd and of the responses of the eggs and larvae to different temperatures and treatment systems is important for effective management and safe recycling of wastes.