Studies on the sequential pathology of Kyasanur Forest Disease (KFD) in Mouse brain: KFD virus induces apoptosis of neurons in cerebrum and hippocampus.

The sequential pathology of Kyasanur forest disease (KFD) in mouse brain was assessed in this study. Kyasanur forest disease virus (KFDV) strain P9605 used in this study was confirmed by real-time reverse transcriptase-polymerase chain reaction targeting the NS5 gene. Mouse Lethal Dose 50 (MLD50) of the virus was determined by in-vivo mice inoculation test. One MLD50 of the KFDV was inoculated intra-cerebrally into 36 mice aged 2-3 weeks. Another group of 36 age-matched mice that served as control group were inoculated with plain media. Six mice each from infected and control groups were euthanized every 24 hrs intervals for six days. Brain tissues were collected in 10% NBF. The collected brain tissues were processed and subjected to histopathological studies by Hematoxylin and Eosin staining. Grossly, the infected mice showed symptoms of dullness, hunched back appearance, weakness, sluggish movements with indication of hind quarter paralysis on day four post-infection. These symptoms got aggravated with complete paralysis of the hind quarters, inability to move and death on 5th and 6th day post-infection. Microscopically, the brain showed apoptosis of neurons, perivascular cuffing, gliosis, congestion, neuropil vacuolation, meningitis, degeneration, and necrotic neurons. The real-time RT-PCR on hippocampus of the KFDV-infected mouse brain showed three-fold higher expression levels of Caspase 3, a crucial mediator of apoptosis. The cerebral cortex, cerebellum and hippocampus that control the motor neuron activities and muscle tone were primarily affected, possibly correlating with the gross symptoms of hind quarter paralysis, ataxia, and other motor neuron dysfunctions noticed. Taken together, these findings reveal that KFDV induces apoptosis of neurons in the cerebrum and hippocampus of KFDV infected mice. Further studies are needed to confirm if the lesions noticed in mice brain simulate the brain lesions in humans since gross motor-neuron symptoms are similar in mice as well as humans.

Multiplex PCR for detection of Anaplasma marginale, A. bovis and A. platys in cattle.

Anaplasma genus has been classified under the family Anaplasmataceae of order Rickettsiales, which contains the spp. Anaplasma marginale, Anaplasma bovis, Anaplasma centrale, Anaplasma platys and Anaplasma phagocytophilum is accountable for a broad range of diseases in both man and animal medicine around the globe. A multiplex PCR procedure was designed to identify A. marginale, A. bovis, and A. platys simultaneously by employing species-specific primers targeting the msp4 (Anaplasma marginale), 16S rRNA (Anaplasma bovis), and groEL (Anaplasma platys) genes. The sensitivity of the assay was ascertained by tenfold dilutions of DNA obtained from cattle blood infected with A. marginale, A. bovis, and A. platys was used to evaluate the test sensitivity. A total of 31 Anaplasma genus positive samples were subjected to mPCR by using species specific primers for simultaneous detection of all the three species. All the 31 samples showed amplification of 753 bp fragment specific for A. marginale and 61.29% of the samples showed amplification of 547 bp fragment specific for A. bovis. The 470 bp DNA fragment specific for A. platys was found in 96.7% of samples. The lower limit of detection of the method for A. platys, A. marginale and A. bovis was found to be 4.4, 0.44 and 0.044 ng/µl, respectively.

Evaluation of Safety and Potency of Kyasanur Forest Disease (KFD) Vaccine Inactivated with Different Concentrations of Formalin and Comparative Evaluation of In Vitro and In Vivo Methods of Virus Titration in KFD Vaccine.

We evaluated the safety and potency of the Kyasanur Forest disease (KFD) vaccine inactivated with different formalin concentrations in mice, since the side effects due to higher formalin concentrations have been a major reason for vaccine refusal. Furthermore, with an objective to reduce the use of mice in vaccine testing, we performed quantification of the KFD virus by real-time PCR and compared it with in vivo titration in mice. The KFD vaccine prepared in chicken embryo fibroblast cells was inactivated with 0.04%, 0.06%, and 0.08% concentrations of formalin. The vaccine inactivated with 0.04% and 0.06% formalin failed the safety test, whereas the KFD vaccine inactivated with 0.08% formalin was safe and potent with a log protective index of 5678 in mice. This reduced formalin content may induce no/lesser side-effects of pain/swelling which may increase the vaccine acceptance. The real-time PCR on individual KFD vaccine harvests interpreted that when the CT value of each harvest is <20, the vaccine will have sufficient viral particles to pass the potency test. Comparison of the real-time PCR on tenfold dilutions of the pooled harvests with in vivo mice inoculation test revealed that the 1MLD50 of the vaccine lies in the tenfold dilution that yields CT values between 31 and 34.