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

Abstract

Experiments 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.

Viability of Bovine`s Strongyloidea eggs in a System of Anaerobic Biodigestion

“…Concerning Strongyloidea eggs, the product of this system became negative on the 35th day of observation. These results differ from another experiments in wich even at lower temperatures (18ºC to 22ºC) it was obtained a lower survival time for eggs of the Trichostrongylus colubriformes, Cooperia punctata, Ostertagia ostertagi species and of the Strongyloides genus -between 7 and 28 days, in liquefied manure [15][16][17] . These authors managed to increase the longevity of the Strongyloidea eggs from 64 to 172 days respectively, only when the manure temperatures lowered to 8ºC and 3ºC.…”

Microbiological aspects of aerobic thermophilic treatment of swine waste

“…Land spreading has been the main method of manure disposal and has resulted in direct and indirect pollution of adjacent watercourses. Swine waste has large amounts of organic matter, ammonia nitrogen, malodorous compounds (24,25), and potential viral, bacterial, and parasitic pathogens for humans and animals (3,17,18). Aerobic biological treatment offers a rapid and effective means of degrading the substrate in an inoffensive manner.…”