Atotal of three pigs; two from Mumbai and one pig from Nagpur were found to beheavily affected with Cysticercuscellulosae on post-mortem examination giving a prevalence of 0.
23% and0.63% for Mumbai and Nagpur region respectively with an overall prevalence of0.3%.Theobservations on prevalence of porcine cysticercosis for Mumbai region was inaccordance with the reports of Mandakhalikar et al.
(2009) and Bhadrige et al. (2014) who reported prevalence of 0.89%and 0.
57% respectively. However theresults are on lower side as compared to those of Palampalle (2012) whoreported presence of T. solium cystsamong 1.26% pigs slaughtered in Mumbai region. This variation can be attributedto the number of samples collected, variations in rearing and housingmanagement, season of study and age, sex and breed of animals during thesestudies.
The prevalence in the Nagpur region could not be discussed due to lackof reports from this region. When compared with the studiesconducted in different states of India, the researchers reported the prevalenceof cysticercosis in the range of 1.75% to 9.3%; Pathak and Gaur (1989), D’Souzaet al. (1998), Sharma et al. (2000), Singh et al. (2003), Hafeez et al. (2004), Sharma et al.
(2004), Raut et al. (2012), Saravanan etal. (2014), Sahoo et al. (2016).
Thevariation in the prevalence might be due to several factors such as climaticconditions, use of sanitary measures for sewage disposal, use of sanitarylatrines, pig rearing by intensive farming so that access to human night soiland sewage is less and maintenance of proper personal hygiene.Theoverall prevalence of 0.3% recorded in the present study is comparatively lessas compared to the various studies conducted in various parts of world bydifferent researchers namely Sarti et al. (1992), Qian et al.
(1998), Phiri et al. (2002), Joshi et al. (2003), Ngowi et al. (2004), Boa et al. (2006), Praet et al.(2010), Eshitera et.al.
(2012), Kombaet al. (2013), Karshima et al (2013), Porphyre et al. (2015), Khaing et al. (2015), Schmidt et al.
(2015) who reported theprevalence in the range of 2.54 to 23.67%. The variation in the prevalence maybe due to the different factors such as disposal of human waste, pig rearing ormanagement system, breed of the animal, sewage disposal system and differentparameters implemented for detection of cysticercosis such as tongue palpation,complete or partial postmortem examination. Parasitological examination of thecystsTwoto four representative cysts from each region were examined under microscope bypressing between two clean grease free glass slides. The scolex revealed four roundsuckers and the rostellum was armed with two rows of hooks i.
e. small and largehooks arranged in alternate manner (13 hooks in each row) (fig. 10) confirmingit to be Cysticercus cellulosae. Boaet al. (1995) reported that the meannumber of hooks on the protoscolices was 27 after examining 83 pig carcasseswhile Chawhan et al. (2016) reported12-14 numbers of large and 9-12 numbers of small hooks after doingmorphological examination of 22 positive carcasses.Gross and HistopathologicalexaminationGrossly,the cysts were grayish white in colour having transluscent bladder wall containingcystic fluid.
The cysts measured from 2 mm to 1 cm in diameter having a singleinvaginated scolex appearing as a white spot. They were lodged in skeletalmuscles throughout the body and also embedded in various visceral organs likeheart, brain, diaphragm, liver and tongue (fig. 1, 2, 3 & 4).Histologicalsection of brain revealed cyst located in cerebrum. Brain revealed markedvascular congestion of meninges, mild neuronal degeneration, perivascularcuffing and gliosis (fig. 5 & 6). Similar changes were revealed in otherpigs with cysts.
Intensity of infiltration was different. Similar changes wereobserved by Kumar et al. (2013) andSahoo et al. (2016) who reported moderateto marked vascular congestion of meninges, leptomeningitis, encephalitis, mildneural degeneration, perivascular cuffing, neuronophagia and focal areas ofgliosis.
The developed cyst in white matter had thick wall. Tissue surroundingthe parasite revealed infiltration of mononuclear cells. There is mildengorgement and compression of brain parenchyma surrounding the attachment ofcyst. Varying degree of inflammatory cellular changes was observed by Borkatakiet al. (2012) and Sahoo et al. (2016).Histopathologicalexamination of liver showed the infiltration of mononuclear cell predominantlyeosinophils throughout the liver parenchyma. There was a thick layer ofinfiltrating cells composed of mononuclear cells and neutrohphils and fibrousconnective tissue proliferation around parasitic granuloma (fig.
7 & 8). Somedegree of calcification was observed in the cysts lodged in liver whilecalcification was not evident in case of cysts lodged in brain, tongue,diaphragm and skeletal muscle. Kumar etal.
(2013) observed some focal areas of calcification in the cystic wall inbrain. Borkataki et al. (2012)experimentally induced the infection in Hampshire male piglets and after 90DPI, the histopathology of liver of slaughtered animals revealed hydropicdegeneration of hepatic parenchyma, dilatation of sinusoids and bile ductproliferation along with granulomatous lesions. Crosssection of the cyst revealed membrane surrounding mouth parts and spinal canal.
The cysts were infiltered with eosinophils. Torre et al. (1998) observed the presence of host inflammatory cells inthe spinal canal of Taenia soliumcysts from naturally infected pigs. Mouth parts had clear suckers and rostellumwith hooks confirming it to be metacestode of Taenia solium (fig. 9).