Paratuberculosis: The Hidden Killer of Small Ruminants

Abstract

Paratuberculosis (PTB) is a contagious and chronic enteric disease of ruminants and many non-ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), and is characterised by diarrhoea and progressive emaciation with consequent serious economic losses due to death, early culling, and reduced productivity. In addition, indirect economic losses may arise from trade restrictions. Besides being a production limiting disease, PTB is a potential zoonosis; MAP has been isolated from Crohn’s disease patients and was associated with other human diseases, such as rheumatoid arthritis, Hashimoto’s thyroiditis, Type 1 diabetes, and multiple sclerosis. Paratuberculosis in sheep and goats may be globally distributed though information on the prevalence and economic impact in many developing countries seem to be scanty. Goats are more susceptible to infection than sheep and both species are likely to develop the clinical disease. Ingestion of feed and water contaminated with faeces of MAP-positive animals is the common route of infection, which then spreads horizontally and vertically. In African countries, PTB has been described as a “neglected disease”, and in small ruminants, which support the livelihood of people in rural areas and poor communities, the disease was rarely reported. Prevention and control of small ruminants’ PTB is difficult because diagnostic assays demonstrate poor sensitivity early in the disease process, in addition to the difficulties in identifying subclinically infected animals. Further studies are needed to provide more insight on molecular epidemiology, transmission, and impact on other animals or humans, socio-economic aspects, prevention and control of small ruminant PTB.

Johne's disease in two Korean black goats (Capra hircus coreanae) with clinical and subclinical infection: A case report

“…Histopathological examination of the gastrointestinal tissues also showed moderate-to-severe lesions in case 1, but mild or no lesions were observed in Case 2. Case 1 showed typical histopathological lesions in the jejunum, ileum, and colon of MAP-infected goats, as previously reported ( Idris et al., 2021 ; Kim et al., 2015 ; Rhyoo et al., 2013 ), whereas we could not detect any specific lesions in the ileum and colon tissue from case 2 goats. Although the ileum is known as the primary point of MAP invasion and localization within the host animal ( Arsenault et al., 2014 ), AFBs were observed only in the jejunum tissue, not in the ileum and colon, in Case 2.…”

First Report on Ovine Paratuberculosis in the Sudan: Diagnosis Using Different Techniques

“…Diagnosis of PTB by isolating MAP by culture is the “gold standard” [ 15 ]. However, Coelho et al [ 31 ] stated that the sensitivity of MAP culture from faeces and tissue is less when compared with molecular methods and histopathology to confirm PTB in clinically diagnosed animals.…”

“…Unfortunately, PTB remains neglected despite very early reports about this disease [ 11 , 12 , 13 , 14 ]. This could be due to poor awareness about the disease, lack of guiding clinical signs (such as shooting profuse diarrhoea in bovines), the unavailability of improved/highly sensitive diagnostic assays [ 15 , 22 , 35 ], and the difficulty in recognizing latent and sub-clinical disease, especially in open pasture; however, the movement of animals in the range system with the possibility of passing large amount of faeces in the resting area at night before starting grazing the next morning seems to help in decreasing the chances of being infected. In addition, in lush pastures, sheep graze the top grass, lessening the possibility of contact with faeces.…”

“…Despite having been diagnosed in the Sudan in cattle and goats earlier [ 11 , 12 , 13 ], and MAP was isolated for the first time from goats in the country [ 14 ], reports on PTB in the Sudan are scarce, especially in small ruminants [ 15 ]. However, two recent seroprevalence studies on bovine PTB [ 16 , 17 ] suggested that the disease is widely spread among dairy cattle herds but has never been reported in sheep.…”

“…Moreover, sheep play important socio-economic roles in rural communities, in addition to providing milk and meat for domestic consumption [ 19 ]. This role would be greatly reduced by diseases of chronic courses, such as PTB, which has been described as a hidden killer [ 15 ]. Here, we report on ovine PTB in the Sudan for the first time after suspicion of the disease in a breeding flock with a history of an unknown wasting condition.…”