Veterinary Medicine and Animal Science Environmental tolerance of the free-living stages of the poultry roundworm (Ascaridia galli) Behdad Tarbiat Department of Biomedical Sciences and veterinary Public Health Degree project/Master’s thesis • 60 hp • Level• A2E Environmental tolerance of the free-living stages of the poultry roundworm (Ascaridia galli) Behdad Tarbiat Supervisor: Johan Höglund, Swedish University of Agricultural Sciences, Veterinary Medicine and Animal Science, Parasitology Assistant Supervisor: Désirée Jansson, Swedish University of Agricultural Sciences, National Veterinary Institute Examiner: Adam Novobilsky, Swedish University of Agricultural Sciences, Veterinary Medicine and Animal Science, Parasitology Credits: 60 hec Level: Advance level, A2E Course title: Degree Project in Animal Science Course code: EX0715 Place of publication: Uppsala Year of publication: 2012 Cover picture: Behdad Tarbiat Online publication: http://stud.epsilon.slu.se Keywords: Ascaridia galli, Roundworm, Organic farm, Laying hens, Prevalence, environmental factors Sveriges lantbruksuniversitet Swedish University of Agricultural Sciences Veterinary Medicine and Animal Science Department of Biomedical Sciences and veterinary Public Health Parasitology 2 3 Table of Contents 1 Abstract ................................................................................................................ 6 2 List of figures ........................................................................................................ 7 3 List of tables ......................................................................................................... 7 4 Abbreviations used in the text .............................................................................. 8 5 Introduction ......................................................................................................... 9 5.1 General overview .................................................................................................. 9 5.2 Statement of problem ......................................................................................... 10 5.3 Objectives of study .............................................................................................. 13 6 Literature review ................................................................................................. 14 6.1 Morphology ........................................................................................................ 14 6.2 Life cycle ............................................................................................................. 14 6.3 Pathogenesis and clinical symptoms .................................................................... 15 7 Materials and methods ........................................................................................ 17 7.1 Preparation of eggs ............................................................................................. 17 7.2 Temperature assay .............................................................................................. 18 7.2.1 Preparation of the media ........................................................................................ 18 7.2.2 Methods ................................................................................................................... 18 7.3 pH assay.............................................................................................................. 19 7.3.1 Preparation of the media ........................................................................................ 19 7.3.2 Methods ................................................................................................................... 19 7.4 Humidity assay .................................................................................................... 20 7.4.1 Preparation of the media ........................................................................................ 20 7.4.2 Methods ................................................................................................................... 20 7.5 Anthelmintic assay .............................................................................................. 21 7.5.1 Preparation of different thiabendazole (TBZ) dilutions .......................................... 21 7.5.2 Methods ................................................................................................................... 21 7.6 Disinfectant......................................................................................................... 22 7.6.1 Preparation of the media ........................................................................................ 22 7.6.2 Methods ................................................................................................................... 22 7.7 Oxygen ............................................................................................................... 22 7.7.1 Preparation of the media ........................................................................................ 22 7.7.2 Method .................................................................................................................... 22 7.8 Freezing and thawing .......................................................................................... 23 7.8.1 Methods ................................................................................................................... 23 8 Morphological classification of the embryonic stages of A. galli ........................... 24 4 9 Results ................................................................................................................. 25 9.1 Temperature ....................................................................................................... 25 9.2 Aging .................................................................................................................. 27 9.3 pH ....................................................................................................................... 27 9.4 Humidity ............................................................................................................. 28 9.5 Anthelmintic ....................................................................................................... 29 9.6 Disinfectant......................................................................................................... 30 9.7 Oxygen ............................................................................................................... 31 9.8 Freezing and thawing .......................................................................................... 31 10 Discussion ............................................................................................................ 32 10.1 Temperature ....................................................................................................... 32 10.2 Aging .................................................................................................................. 34 10.3 pH ....................................................................................................................... 34 10.4 Humidity ............................................................................................................. 35 10.5 Anthelmintic ....................................................................................................... 37 10.6 Disinfectant......................................................................................................... 39 10.7 Oxygen ............................................................................................................... 39 10.8 Freezing-thawing ................................................................................................. 41 11 Conclusion ........................................................................................................... 43 12 Recommendation ....................................................... Error! Bookmark not defined. 13 Acknowledgment ................................................................................................. 46 14 References ........................................................................................................... 47 5 1 Abstract As the EU ban on conventional cages (1999 EU-directive) drew closer, most European countries moved towards alternative systems. Consequently, barn and free-range systems has become increasingly popular. Regardless of how welfare has improved, this major change in husbandry likely affects the parasite transportation. Accordingly, recent reports have unanimously shown that prevalence of round worm infection, in particular Ascaridia galli has increased dramatically. Although management practices have shown to be somehow efficient with regard to parasite control in caged system, at this time there is no effective way to prevent and eliminate the existing parasite in non-caged system. For better understanding the infection dynamics of A. galli a series of experiments was carried out to study the environmental factors (temperature, relative humidity, pH and oxygen) influencing the fate of A. galli eggs within the environment. In addition, two more experiments were run to evaluate the efficacy of thiabendazole and commercial broad spectrum disinfectant Chlorocresol (Interkokask). Survivability of the eggs with regard to the age of the parasite eggs was investigated as well. The results presented herein suggest that there is a direct relationship