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Browsing by Subject "Johnen tauti"

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  • Soininen, Riikka (University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2015)
    The aim of this licentiate thesis is to assess by literature the potential exposure of humans to Mycobacterium avium subspecies paratuberculosis (MAP) through food and drinking water in Finland and Minnesota, USA and to represent the prevalence (the total number of cases of a disease at a specific time) of Johne's disease and the prevalence and incidence (the number of new cases of a disease during a certain period of time) Crohn's disease in the United States, Minnesota and Finland. Johne's disease (JD), also known as paratuberculosis, is a globally important chronic intestinal disease of cattle and other ruminants such as goats and sheep caused by MAP. Crohn's disease (CD) is a chronic intestinal disease of humans. The etiology of CD is unknown but in addition to genetic susceptibility, environmental factors have been found to have an impact on the onset of the disease. It has been suggested that MAP could be one of the etiologic agents of CD. In the United States, JD is more common in dairy cattle than in beef cattle. The apparent cow-level prevalence is 6% and apparent herd-level prevalence is 68 % in dairy cattle. In Minnesota the apparent prevalence of JD in dairy cattle at the cow-level is 3% and at the herd-level 46%. In beef cattle the prevalence at the cow-level is only 0.3 % in Minnesota. The prevalence of CD in the United States is 241/100,000 and the annual incidence 20/100,000. The prevalence of CD in Minnesota is 222/100,000 and the annual incidence 13/100,000. In Finland, JD has been diagnosed in five beef cattle herds since 1992. The disease has not been diagnosed in dairy cattle or sheep or goats in Finland. The prevalence of CD in Finland is 124/100,000 and the annual incidence 9/100,000. The prevalence of MAP in food and drinking water in Finland has not been studied. Despite this, it is unlikely that people are exposed to MAP through drinking water or by eating foods of Finnish origin because the prevalence of JD in Finland is very low. However, exposure to the bacterium is possible by eating imported beef and dairy products such as cheese and yogurt. The share of imported foods within these food groups is relatively large in Finland. Dairy products and beef are imported for example from Germany and Denmark where the prevalence of JD at the herd-level is about 50–80 %. In the United States the occurrence of MAP in foods and drinking water has been studied quite much. It appears that the bacterium is found in foods and drinking water of U.S. origin. Because JD is so common in the United States and Minnesota, it is likely that people are exposed to the bacterium in Minnesota even though not all the food eaten is produced in the state. It is likely that people in areas of high prevalence of JD are exposed more to MAP than people in areas of low prevalence of JD. Comparing subsets of CD patients with high exposure to MAP to healthy controls with and without exposure to MAP could reveal the possible role of MAP in the complex etiology of CD. Based on this literature review it can be assumed that in Finland CD is caused by some other environmental agent than MAP. This licentiate thesis sets up further research needs to estimate the true human exposure to MAP.