Risk Factors for Nipah Virus Encephalitis in Bangladesh1

Abstract

Nipah virus (NiV) is a paramyxovirus that causes severe encephalitis in humans. During January 2004, twelve patients with NiV encephalitis (NiVE) were identifi ed in westcentral Bangladesh. A case-control study was conducted to identify factors associated with NiV infection. NiVE patients from the outbreak were enrolled in a matched case-control study. Exact odds ratios (ORs) and 95% confi dence intervals (CIs) were calculated by using a matched analysis. Climbing trees (83% of cases vs. 51% of controls, OR 8.2, 95% CI 1.25-∞) and contact with another NiVE patient (67% of cases vs. 9% of controls, OR 21.4, 95% CI 2.78-966.1) were associated with infection. We did not identify an increased risk for NiV infection among persons who had contact with a potential intermediate host. Although we cannot rule out person-to-person transmission, case-patients were likely infected from contact with fruit bats or their secretions.

Nipah virus infection: current scenario

“…Widespread surveillance of pig populations to detect infected pigs, and culling of sick pigs stopped the epidemic [67]. Urine exposure may also be associated with transmission as NiV antigen has been demonstrated in the renal tubules of pigs and a concurrent outbreak of NiV among abbatoir workers in Singapore also showed the associatedness of infected pig urine and exposure to the workers [67,68].The possible mechanical transmission by repetitive use of same needles or equipment without further sterilization after each use for health intervention and artificial insemination and sharing of boar semen within a farm were also implicated. The possible role of transmission by infected dogs and cats found in the affected farm could not be excluded [12].…”

“…Investigation of different Nipah outbreaks in Bangladesh have identified different routes of transmission including climbing trees (probably contaminated with infected date palm sap), contact with sick persons, and contact with sick animals [39,[44][45][46]68]. Another way of NiV getting transmitted from P. giganteus to humans recorded in Bangladesh is food-borne.…”

Cysteines in the Stalk of the Nipah Virus G Glycoprotein Are Located in a Distinct Subdomain Critical for Fusion Activation

“…This emergent zoonotic disease has spread to Singapore, India, and Bangladesh, with recurrent outbreaks continuing in Bangladesh almost yearly for the past decade. Cited causes of NiV infections in Bangladesh include drinking contaminated palm date juice and close contacts of individuals with pteropid fruit bats, considered the natural reservoir host (13,24,28). What was first seen as a disease with little to no human-to-human transmission is now known to have a human-to-human transmission rate of approximately 50% in recent outbreaks, with mortality rates as high as 70% (23).…”

Nipah Virus: A Hidden and Continuous Threat to Humankind

“…Two outbreaks in India and several outbreaks in Bangladesh between 2001 to 2013 did not show any involvement of pigs. Outbreak investigations in Bangladesh identified another routes of viral transmission which included climbing tree, consumption of raw date palm sap and contact with sick person or animals (22) Pteropidusgiganteus (fruit bats) drinks the sap from the collecting pots at night and even contaminates the pot through their urine. Consumption of contaminated raw date palm sap transmits the virus to humans (23) .…”