Histopathological changes of brucellosis in experimentally infected guinea pig

Abstract

Background: Brucellosis, a chronic infectious and zoonotic disease, is endemic in many countries of the world including Bangladesh, that affects humans and animals, leading to significant impact on public health and animal industry. There are several reports on seroprevalence, risk factors, molecular, epidemiological and review of brucellosis in human and animals but least of histopathological reports in Bangladesh. As laboratory animal species guinea pigs are the most susceptible to Brucella infection in comparison to mice, monkeys, rats and sheep. Hence, this study was undertaken to determine the histopathology of brucellosis in guinea pig. Methods: After collection of aborted bovine foetal membranes from the Central Cattle Breeding and Dairy Farm (CCBDF), Savar, screened with modified Ziehl-Neelsen staining method and inoculum (10 CFU/2ml) prepared from positive samples were inoculated into each of ten guinea pig. The guinea pigs were sacrificed after showing positive results from the serum in Rose Bengal test and from blood in rapid kit test 3 weeks post inoculation. Then the gross and histopathological lesions were observed in the liver, spleen, heart, lungs, and kidneys. Results: Liver showed congestion, haemorrhage and fatty changes and granuloma formation with infiltration of macrophages. However, only caseous necrosis of splenic follicle was observed in spleen. The major findings in lungs of guinea pig were granuloma, haemorrhage and necrosis of lung parenchyma and mononuclear cellular infiltration. The heart revealed haemorrhagic endocarditis and monocytes infiltration. A variable degree of multifocal accumulation of mononuclear cells infiltration and congestion were found in kidneys. Conclusions: It is concluded that the histopathological changes caused by Brucella spp. are similar to those observed in humans with brucellosis. The animal models, particularly the guinea pig, can be used to study the detail pathogenesis of this organism.