A single case outbreak of Nipah Encephalitis from India in May–June 2019

Abstract

Background: Nipah Encephalitis outbreaks have mostly been involving multiple patients; mostly close contacts like family members, Franceiends and healthcare workers from the hospitals. We report a case of Nipah Virus Encephalitis, which had a sub-acute presentation, had prolonged viral shedding with symptoms but no documented secondary cases in spite of many having prolonged and close contact with the patient. Case description: A 21-year-old male was admitted with fever, altered sensorium and cerebellar signs of 12 days duration. A MRI showed multiple hypintense lesions in T2 images through out the brain parenchyma and the CSF, throat swab and Urine was positive for Nipah Virus RT-PCR. The urine remained positive for 3 weeks. He was treated with Ribavirin and Immunoglobulins and discharged well after 51 days of hospitalization. Contact tracing of all the healthcare workers (HCW) and the care givers (family) who had come into close contact from admission to discharge was done.There were a total of 94 HCW contacts Seven HCW developed acute respiratory symptoms within the defined surveillance period. All of these symptomatic contacts were tested for Nipah virus (throat swab & serology) and were negative. Patient's mother and aunt who had cared for him though out his illness of 12 days before the diagnosis were also tested and were found to be sero-negative for Nipah. Discussion: This is the second instance among the reported outbreaks where there was only one patient involved, the previous one being in 2009–10 in Rajbari, Bangladesh. This was in all probability a case with very low transmission capability, as even the close family members who cared for him for 12 days with out any precautions, and had exposure to urine, which was positive for Nipah, did not contract the disease. Absence of overt respiratory involvement in the late phase and possible strain differene could have contributed to low transmissibility both prior to hospitalization and during the hospitalization. Conclusion: Transmission rates are not same for all strains of Nipah Virus. With only standard precautions, we can prevent outbreaks in these cases.