Tarbiat Behdad, Jansson Désirée S, Höglund Johan
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.
Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
Vet Parasitol. 2015 Apr 15;209(1-2):101-7. doi: 10.1016/j.vetpar.2015.01.024. Epub 2015 Feb 4.
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.
由于非笼养环境的增加，家禽蛔虫鸡蛔虫正在许多欧洲国家的蛋鸡中再度出现。开展了一系列体外实验，以研究不同环境条件下的卵内幼虫发育（胚胎发育）情况。在20至30°C的水中孵化7至21天内，83%至96%的卵发育至L3期。31天后，26%的卵在33°C时完成发育，4%的卵在35°C时完成发育。在15°C时，寄生虫卵发育缓慢，56天后只有8%发育至L3期。在另一项试验中，当寄生虫卵经历冻融循环（30分钟至12小时），然后在25°C下孵化2周时，幼虫发育发生了。pH值在2.5至12.5范围内的碱性和酸性条件对发育没有不利影响。发育需要氧气和相对湿度高于70%。因此，一些鸡蛔虫卵可能在温带气候区家禽舍全年普遍存在的条件下完成发育。虽然接触1%或2%稀释的广谱消毒剂氯甲酚4小时或更长时间可杀卵，但需要进一步开展工作以改进现场应用方法。
