Pathological and molecular investigation of porcine kobuvirus (PKV) from Indian pigs

The porcine kobuvirus (PKV) is a single-stranded, positive-sense, RNA virus of the family Picornaviridae which composed of small, non-enveloped viruses. The PKV is suspected to cause large outbreaks of diarrhoea and dehydration along with vomition in suckling piglets with a high morbidity rate. Despite of its economical importance very few studies are available on the pathology of PKV. The present study was conducted with the aim to investigate PKV in naturally infected Indian pigs. A total of 41 intestinal content and tissue samples from dead pigs were collected from post-mortem facility of, ICAR-IVRI during April, 2019 to July 2020. All the carcasses were subjected to detailed necropsy examination and appropriate tissue samples were collected for histopathological examination and molecular investigation. The amplification of 3D region of PKV was carried out via RT-PCR using the specific primers. The Genetic characterization of Indian isolate of the PKV was done on the basis of viral 3D gene of PKV. A total of six out of 41 necropsied piglets were found positive for the PKV. The diarrhoea and dehydration were observed as the main clinical signs. The thickening and clouding of brain meninges, congestion of brain, pneumonia along with catarrhal and haemorrhagic enteritis was observed as common gross lesions. Microscopic lesions observed in brain were mild to moderate perivascular cuffing, congestion of meningeal and cerebral vessels, focal gliosis and neuronophagia. Mild to severe interstitial pneumonia and emphysema was noticed in lungs. Intestinal mucosa revealed severe inflammatory changes along with sloughing of villi. The genetic characterization revealed maximum identity of 91–93% with Indian isolate of PKV MH394282 and Chinese strain of PKV FJ459905. This study reported the first pathological investigation of PKV from Indian pigs and described the molecular findings in detail. Further explorative surveillance along with epidemiological studies are highly warranted to find out the real impact of the PKV on Indian pigs.