Fascioliasis may promote tuberculous infectivity in small ruminants

Fascioliasis and bovine tuberculosis (TB) are global impediments to livestock development. We investigated the co-infectivity of fascioliasis and TB in small ruminants at slaughter. A total of 84 goats and 16 sheep were investigated from different slaughter houses in Mymensingh city, Bangladesh from June 2019 to February 2020. Grossly, acute fascioliasis was characterized by hemorrhagic tracts in the liver and chronic fascioliasis with biliary cirrhosis and pipe-stem liver. Grossly, seven goats and two sheep were associated with the acute and sixty goats and seven sheep were associated with the chronic phase of fascioliasis. Five goats’ livers showed both the acute and chronic phases of fascioliasis. In TB, granulomas with central core of caseous necrosis were seen in the lymph nodes (21), livers (10) and lungs (01) of goats or in the lymph nodes (03) and liver (01) of sheep. Histopathologically, biliary cirrhosis was seen in fascioliasis and granuloma, caseous necrosis and calcification in TB. In co-infection revealed granuloma (TB) with acid-fast bacilli and widespread biliary cirrhosis in the livers of goats (14) and sheep (02). The fragments of the 16S rRNA gene (372 bp, M. tuberculosis complex) and MPB83 gene (600 bp, M. bovis) were detected in the lymph nodes, livers and lungs using polymerase chain reaction. This study showed the existence of co-infectivity of Fasciola and M. bovis in goats and sheep in Bangladesh. Chronic fascioliasis may be associated with establishing tuberculous infection in small ruminants. Therefore, extremely zoonotic bovine TB control programs require active management of fascioliasis.