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      Anonymous
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      In the light of the recent Nipah virus outbreaks in Kerala, it is very important to know more about the virus and its effects. This article gives a summary of the outbreaks in the past; and gives an overview of how it has been dealt and what studies are carried out to determine the treatment.

      The recent outbreak of Nipah virus (NiV) in Kerala has baffled doctors and scientists nationwide. This is the third NiV outbreak since 2001; the second being the 2007 event. Even though the state and central health agencies have increased the efforts to contain the deadly viral spread, the total deaths from the contagious Nipah virus infection in Kerala reached 14 on 22nd May 2018, Tuesday.

      Background – What? How? Where?

      NiV, an emerging zoonotic pathogen, infects humans causing encephalitis. This virus can be transmitted between humans to a certain extent. NiV was first identified as a causative agent of the outbreaks in pigs and encephalitis in humans, in Malaysia and Singapore in 1998. Soon, in 2001, India and Bangladesh witnessed the outbreak caused by NiV. Every year since then, such outbreaks have been reported in Bangladesh; a few cases also reported in the India-Bangladesh borders.

      The initial advances in the spread of the disease were amplified by person-to-person transmission. Interestingly, the case-fatality rate for patients in Malaysia and Singapore was around 40% as compared to that of India and Bangladesh, which exceeds 70%.

      Old World fruit bats of the genus Pteropus, found in eastern Africa and throughout Asia, Pacific islands and Australia, is the natural reservoir for NiV. Pteropus medius is the only pteropid bat species in India and Bangladesh, which is also the known reservoir for NiV in this region. Infected bats exuviate NiV in their saliva and urine. NiV transmission could result from human consumption of bats, residing near or under bat roosts; humans consuming fruits or date palm sap previously consumed by bats.

      Symptoms

      After exposure of 5 to 14 days, illness initiates with 3-14 days of fever and headache. This is followed by drowsiness and delirium. This can advance to coma within 24-48 hours. Some patients suffer from respiratory illness during the initial stages of their infections. The long-term consequence of Nipah virus infection includes continuous convulsions and personality changes. Some patients may have latent NiV infections with reactivation after months of exposure that may lead to death.

      Prevention

      NiV has been declared as a priority pathogen by the WHO. Therefore, Coalition for Epidemic Preparedness Innovation (CEPI) is focussing on NiV. Recently, the WHO has declared NiV to be a priority pathogen, and CEPI is, therefore, focusing on NiV as their first disease targets. They plan to have two new experimental vaccines ready, beginning the phase I clinical trials within 5 years so that they will be in a better place for to prevent and manage the event of continued or large outbreaks. Tree skirts must be used to prevent bats from accessing jars used for date palm sap collection (carried out in Bangladesh for consumption) and date palm sap must be boiled for consumption as this inactivates NiV.

      Currently, monoclonal antibodies are the most advanced in preclinical studies. However, antibody-based drugs tend to be expensive and disease-specific. In future, the focus must be on siRNAs, small molecule drugs, screening of currently approved drugs for NiV efficacy and identifying broad-spectrum antivirals.

      Detection

      Kerstin Fischer et al. (2018) developed ELISA based on recombinant proteins for the detection of HeV or NiV specific antibodies in porcine serum samples. They used the NiV (N) ELISA for initial serum screening taking into account the general reactivity against henipaviruses (HeV). The G-protein based ELISA helped to differentiate between HeV and NiV infections since the sera displayed higher reactivity with the respective homologous antigens. These assays will be valuable tools in future for serosurveillance of swine and possibly other livestock or wildlife species in affected regions.

      Treatment

      Dr. Nicholas Paton et al. (1999) carried out a study amidst the Malaysian outbreak of NiV. Eleven patients were confirmed to have an acute Nipah-virus infection based on elevated IgM in serum. The virus was identified by reverse-transcriptase PCR in the cerebrospinal fluid (CSF) and tissue of the patient who died. The common symptoms present were fever, headache, and drowsiness. Eight patients showed signs of encephalitis, three showed atypical pneumonia, but one later developed hallucinations and showed the presence of encephalitis on CSF examination. Laboratory findings revealed abnormally low lymphocyte count, low serum sodium, low platelet count and high aspartate aminotransferase concentration. The CSF protein elevated in eight patients and WBC count was high in seven patients. A mild interstitial shadowing was seen in eight patients in chest radiogram. Magnetic resonance imaging (MRI) showed focal areas of increased signal intensity in the cortical white marker in all eight patients who were scanned. Eight out of nine patients with encephalitis survived following treatment with intravenous acyclovir.

      Summary

      Since vaccines against NiV have not been developed yet and treating the infection can be complex, we must follow preventive measures. The symptoms of the infection are very common and may resemble that of common flu, thus, one must not ignore consulting a doctor and getting yourself tested.

      References

      Kerstin Fischer et al., Indirect ELISA Based on Hendra and Nipah Virus Proteins for the Detection of Henipavirus Specific Antibodies in Pigs, Plos One 2018, Volume 13, Issue 4
      Khean Jin Goh et al., Clinical Features of Nipah Virus Encephalitis among Pig Farmers in Malaysia, The New England Journal of Medicine 2000, Volume 342, Number 17, Pages 1229-1235
      Nicholas Paton et al., Outbreak of Nipah-Virus Infection among Abattoir Workers in Singapore, The Lancet 1999, Volume 354, Issue 9186, Pages 1253-1256

      This was published by Hriticka Choudhurry in Docplexus

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