Population genetics of parasitic nematodes of livestock; the spread of anthelmentic resistance and range expansion in Haemonchus spp

点击翻译按钮获取中文摘要

Parasitic roundworms (nematodes) are important agents of disease in both humans and animals. Such infections are ubiquitous in livestock (cattle, sheep and goats) worldwide and are amongst the most economically important diseases to agriculture. It has been estimated they cost the North American cattle industry more than $2 billion per year. Roundworm control is dependent upon the routine treatment of livestock with drugs (anthelmintics) but many roundworm parasites are now resistant to these drugs making control increasingly difficult.This project focuses on a group of livestock parasites called Haemonchus.There are a number of different species of Haemonchus that live in the stomach of livestock feeding on blood and causing anaemia. These parasites originated in Africa but have spread around the world with livestock movement and, although originally adapted to the tropics, they are now spreading to more northern latitudes including Canada, Western Europe and Scandanavia. This project will develop DNA based tests to detect and identify these parasites. These tools will be used to determine which Haemonchus species are most important in cattle, sheep, goats and wildlife in different regions of the world and in different situations.As well as studying these parasites in tropical regions, we will investigate the spread of the parasite through livestock and wildlife in Canada.We will also use DNA-based techniques to detect drug resistant parasites by detecting mutations in the parasite's DNA that confer resistance to an important class of drugs. We will study how these resistance-conferring mutations are spread between parasite populations. One particular concern is the risk that these mutations could spread from one parasite species to another. This is a particular worry in livestock because drug resistance is extremely common in sheep and goat parasites but is only now emerging in cattle parasites. Consequently we will investigate whether there is spread of drug resistance between sheep and cattle parasites. This project will provide important information needed to control the development of drug resistance and prevent the movement of parasites into new regions and wildlife populations.