Novel pathologic findings and viral antigen distribution in cattle and buffalo calves naturally infected with Foot-and-Mouth disease virus.

The Foot-and-Mouth disease is highly contagious acute viral disease of livestock inflicting huge economic loss to the farmers. The limited knowledge regarding the pathological lesions vis-a-vis distribution of the FMDV in lesser explored endocrine glands and important vital organs other than the target organs of infected calves prompted us to take the present investigation to have detailed insight into the pathogenesis. The systematic necropsy of 37 dead calves (cattle-28 and buffalo-9) was conducted, and thin representative tissue pieces from the affected organs were collected in 10% neutral buffered formalin (NBF) for pathological and immunohistochemical investigations. The genomic detection and its serotyping were done by RT-PCR and multiplex-PCR, respectively. Necropsy examination in all cases showed myocardial lesions resembling 'tigroid heart appearance'. Other organ specific lesions include vesiculo-ulcerative stomatitis, edema of the lungs, petechial hemorrhages, edema of the endocrines, and gastroenteritis. Histopathological examination showed varying sizes of vesicles and ulcerations in stratified squamous epithelium of the tongue, acute necrotizing myocarditis, lymphoid depletion in lymphoid tissues, hepatitis, pancreatitis, thymic hyperplasia, thyroiditis, adrenitis, and enteritis. Positive immunolabeling for viral antigens was observed in endocrine glands, lymphoid organs, lungs, liver, kidneys, and intestine, in addition to other typical locations. The thyroid, adrenal glands, and pancreas, in addition to the tongue and heart, are the tissue of choice for sampling in the field during epidemics. Further, the viral genome and serotype A was confirmed in the affected tissues. This study provides insights into novel tissue tropism and pathogenesis in young calves naturally infected with FMDV.

Japanese encephalitis virus-induced neuropathology in mouse model infected through the conjunctival route.

Background & objectives: Mouse is a preferred animal model for studying pathogenesis of Japanese encephalitis virus (JEV) infections, and different routes of inoculation have been tried. Some neurotropic viruses can reach the brain following infection through ocular route. This study was undertaken to establish JEV-induced clinical disease in mouse model through conjunctival route and document the neuropathological effects. Methods: Ten two-week old Swiss albino mice were inoculated with 5 µl Vero cell cultured virus containing 104.7 TCID50 JEV through conjunctival route. Clinical signs of mice were observed twice daily. After necropsy examination, different organs including eyes and olfactory bulbs were collected for histopathological examination, quantification of viral copy number and antigen by real-time TaqMan assay and immunohistochemistry, respectively. Results: Infected mice showed characteristic clinical signs of JE by 4 days post-infection (dpi). Histopathological lesions in brain included perivascular cuffing by mononuclear cells, focal gliosis, necrosis of neurons and neuronophagia and astrocytosis in the cerebrum, cerebellum and the brainstem. JEV viral load was highest in the brain followed by intestine, heart, liver, spleen, lung and kidney. JEV antigen was detected in the bipolar and ganglion cells of the retina and in the mitral cells and periglomerular cells of olfactory bulb and other parts of the brain. Interpretation & conclusions: JEV infection in mice through conjunctival route produced characteristic clinical signs of the disease and neuropathological lesions. Demonstration of JEV antigen in association with neuropathological lesions in the central nervous system and neuronal cells of the eye showed that conjunctival route could be an effective alternate route for virus invasion into the brain. These findings have biosafety implications for researchers, veterinary practitioners and pig farmers.

Complete Genome Sequence of a Field Isolate of Classical Swine Fever Virus Belonging to Subgenotype 2.2 from India.

The complete genome sequence of classical swine fever virus (CSFV) strain CSFV-UP-BR-KHG-06, from genotype 2.2, was determined. Comparative analysis based on the amino acid sequence of some important B-cell epitopes, T-cell epitopes, glycosylation sites, and conformational residues showed the striking differences between the group 2 virus KHG-06 and the vaccine strains HCLV/India and C-strain.