Implications of between-isolate variation for climate change impact modelling of Haemonchus contortus populations

• Published in: Veterinary parasitology 2016-10, Vol.229, p.144-149
• Main Authors: Rose Vineer, H., Steiner, J., Knapp-Lawitzke, F., Bull, K., von Son-de Fernex, E., Bosco, A., Hertzberg, H., Demeler, J., Rinaldi, L., Morrison, A.A., Skuce, P., Bartley, D.J., Morgan, E.R.
• Format: Article
• Language: English
• Subjects: Animals; Climate Change; Climate impact modelling; Development success; Gastrointestinal nematode; Goat Diseases - epidemiology; Goat Diseases - parasitology; Goats; Haemonchiasis - epidemiology; Haemonchiasis - parasitology; Haemonchiasis - veterinary; Haemonchus - classification; Haemonchus - physiology; Haemonchus contortus; Local adaptation; Models, Biological; Risk Assessment; Seasons; Sheep; Sheep Diseases - epidemiology; Sheep Diseases - parasitology; Temperature; Trait variation
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/j.vetpar.2016.10.015

•Models have been developed to predict changes in parasite distribution & disease risk.•Variation between isolates could undermine the application of such models.•Developmental success of 3 Haemonchus contortus isolates was observed at a range of temperatures.•Observations were compared with H. contortus population dynamics simulations.•Recommendations are made for future climate impact modelling of gastrointestinal nematodes. The impact of climate change on parasites and parasitic diseases is a growing concern and numerous empirical and mechanistic models have been developed to predict climate-driven spatial and temporal changes in the distribution of parasites and disease risk. Variation in parasite phenotype and life-history traits between isolates could undermine the application of such models at broad spatial scales. Seasonal variation in the transmission of the haematophagous gastrointestinal nematode Haemonchus contortus, one of the most pathogenic helminth species infecting sheep and goats worldwide, is primarily determined by the impact of environmental conditions on the free-living stages. To evaluate variability in the development success and mortality of the free-living stages of H. contortus and the impact of this variability on future climate impact modelling, three isolates of diverse origin were cultured at a range of temperatures between 15°C and 37°C to determine their development success compared with simulations using the GLOWORM-FL H. contortus model. No significant difference was observed in the developmental success of the three isolates of H. contortus tested, nor between isolates and model simulations. However, development success of all isolates at 37°C was lower than predicted by the model, suggesting the potential for overestimation of transmission risk at higher temperatures, such as those predicted under some scenarios of climate change. Recommendations are made for future climate impact modelling of gastrointestinal nematodes.