title: Environmental tolerance of free-living stages of the poultry roundworm Ascaridia galli.
abstract: The poultry roundworm Ascaridia galli is re-emerging in laying hens in many European countries due to the increase in non-caged housing. A series of in vitro experiments was carried out to study the in ovo larval development (embryonation) under different environmental conditions. Between 83% and 96% of the eggs developed to L3 within 7-21 days of incubation in water between 20 and 30°C. Twenty-six percent completed development at 33°C and 4% at 35°C after 31 days. At 15°C parasite egg development was low with 8% L3 after 56 days. In another trial larval development occurred, when parasite eggs were exposed to freeze-thaw cycle (30' to 12h) followed by incubation for 2 weeks at 25°C. Alkaline and acidic conditions in the range of pH 2.5-12.5 had no adverse effect on development. Oxygen and relative humidity above 70% were necessary for development to occur. Thus, some A. galli eggs may complete development at conditions prevailing in poultry barns in temperate climate zones throughout the year. Although exposure to a 1% or 2% dilution of the broad-spectrum disinfectant chlorocresol for 4h or longer was ovicidal, further work is required to improve the method of application in the field.
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7009, SE-750 07 Uppsala, Sweden.
authors.forename: Behdad
authors.initials: B
authors.lastname: Tarbiat
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
authors.forename: Désirée S
authors.initials: DS
authors.lastname: Jansson
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7009, SE-750 07 Uppsala, Sweden. Electronic address: johan.hoglund@slu.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Höglund
mesh_terms: D000818:Animals; D001197:Ascaridia / Q000502:physiology*; D002645:Chickens; D003408:Cresols / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology; D004777:Environment; D005260:Female; D006813:Humidity; D010063:Ovum / Q000187:drug effects / Q000502:physiology*; D010100:Oxygen; D011201:Poultry Diseases / Q000469:parasitology
chemical_list: D003408:Cresols; D004202:Disinfectants; C006984:chlorocresol; D010100:Oxygen
keywords: Ascaridia galli; Chlorocresol; Embryonation; Environmental conditions; L(3); Parasite egg