Transcript emilie
Climate Change and the Muskox Nematode Biology 3700 Emilie Ontko March 23rd 2011 Nematode • Umingmakstrongylus pallikuukensis • Large protostrongylid lungworm • Dioeceous • Forms large cysts deep in the lungs • Discovered in Nunavut in 1988 Novel Parasite or New Discovery • No historical baseline for parasites • Not a recent host switch • Reasons for non-detection before 1988: – – – – – Low infection levels Minimal contact between people and Muskox Hunters discard lungs Cysts mistaken for hydatid cysts Highly restricted range • Only detected by luck after follow-up of death of a radio-collared individual Life Cycle Life Cycle Facts • • • • Pre-patency period ~91-95 days Patent period > 22 months L3 larvae ingested during summer Takes two years to mature from L1-L3 in gastropod host • Migration route from GI tract to lungs not known • Cysts: tough, grey and well defined – Contain at least 1 male, 1 gravid female, free eggs and L1 larvae Experimental Results • 1999: Prevalence up to 92% of L1 in fecal samples – Up to 258 cysts in one animal • 2004: Prevalence of infection 100% – Intensity >100 cysts/animal Hypotheses on Pathology • No clinical sign of pathology • In established infections pathology is limited to the cysts • Inflammatory response and small lesions found in developing infection • Exercise intolerance Hypotheses on Pathology • Caused by displacement and compression of alveoli and lung spaces • Infected animals move slower and have been reported to bleed from the nostrils • Predators prey on slow moving animals • Exercise intolerance may be significant Other Definitive Hosts • Investigations of parasite with: – Domestic Sheep – Dall’s sheep – Sympatric moose – Sympatric caribou • Restricted to Muskox • Post mortem Dall’s sheep: no encysted or living parasites, but legions on liver and lungs Climate Change • Significant and unprecedented warming in WestCentral Canadian Arctic and Subarctic – Increase of an average of 2.0 degrees • Earlier springs and later autumns Effect on Muskox • Warmer summers larvae can develop from L1-L3 within the summer • Longer summer increase chance that larvae can develop to L3 in one summer • 50% decline in population in infected areas, other areas increased significantly (Studied 1988-1994) Future Worries • Spread to areas with suitable gastropod host • Prevalence of infection in all infected populations will increase • Possible host switch to more domesticated and utilized host • Switch of other ungulate parasites to Muskoxen References • • • • • • • • Kutz, S.J., Hoberg, E.P., and Polley, L. Experimental infections of muskoxen (Ovibos moschatus) and domestic sheep with Umingmakstrongylus pallikuukensis (Nematoda:Protostrongylidae): parasite development, population structure, and pathology. Canadian Journal of Zoology; Oct 1999. 77(10): 1562-1572 Kutz, S.J., Hoberg, E.P., Nagy, J., Polly, L. and Elkin, E. “Emerging Parasitic Infections in Arctic Ungulates. Integrative and Comparative Biology, Apr. 2004. 44(2): 109-118 Kutz, S., Garde, E., Veitch, A., Nagy, J., Ghandi, F., and Polly, L. Muskox Lungworm (Umingmakstrongylus pallikuukensis) does not establish in experimentally exposed thinhorn sheep (Ovis dalli). Journal of Wildlife Diseases, 2004. 40(2): 197-204 http://mottafied.com/?p=48 http://www.cdc.gov/eid/content/14/1/10-g1.htm http://www.rvc.ac.uk/review/parasitology/LungwormSheepGoat/Dictyocaulus .htm http://www.enr.gov.nt.ca/_live/pages/wpPages/muskox_lungworm.aspx http://www.elcivics.com/mount_mckinley_alaska_3.html