Research targets wasting disease

Researchers aiming to control or even eliminate a disease in farm livestock which costs the nation up to $88 million a year are probing where some genetic types of animal are particularly susceptible or resistant reports Stuff.  A micro-organism with the tongue-twisting scientific label of Mycobacterium avium subspecies paratuberculosis -- also known as MAP -- causes Johne's disease, a chronic wasting intestinal disease in a range of animals, including cattle, deer and sheep. Johnes is spread by the faeces of infected animals and blocks the absorption of food, causing them to waste away and die. Bacteria infect the walls of the intestines, causing a malabsorption syndrome, protein loss from the inflamed bowel, anaemia, and the collapse of the immune system. It can not only mimic other health problems such as chronic parasitism, trace element deficiency and poor nutrition, but also interfere with tests for bovine tuberculosis. The disease can also infect mustelids such as ferrets and stoats, and New Zealand scientists are also looking at whether such species are spreading Johne's disease between different species of farm animals, and different farms. Johne's Disease Research Consortium chairman Dr Andrew MacPherson said the science was focused on fundamentals of Johne's disease, developing better diagnostic tools that enable farmers and veterinarians to more easily identify infected animals, and examining how the disease spreads. "Genetics is another important research area," he said. "We are working to identify a gene marker that does not compromise production but will allow farmers to select for stock that are resistant". Increasing use of DNA screening would make it relatively easy for animals to be selected according to their level of susceptibility to the wasting disease.