Introduction: Nipah virus is considered a biosafety level-4 pathogen that is endemic to bats of the genus Pteropus. Infection in humans presents clinically as febrile encephalitis with an extremely high case-fatality rate (78.2%). Outbreaks of Nipah virus infection have occurred in Bangladesh and India almost annually since 2001, most recently in January 2013.
Methods: To elucidate Nipah virus persistence at the endemic host and human population level we developed a Susceptible-Exposed-Infectious-Recovered dynamic model and parameterized it from published epidemiological case data and serological bats surveys on the Nipah Virus-Bangladesh variant. We conducted a Markov Chain Monte Carlo simulation to estimate the unknown parameters for bat-to-bat, bat-to-human, human-to-human, and corpse-to-human transmission routes.
Results: We present the first estimates of the four disease transmission rates and reproductive numbers of Nipah virus in the human and bat population. Our results indicate that at population equilibrium 1.77 bats per day will have an active infection, additionally 93.0% of human infections are the result of zoonotic transmission, but only 5.3% of these primary cases transmit disease to other humans, which may indicate the presence of super-spreaders.
Conclusions: This work draws conclusions about enzootic viral maintenance of Nipah in the bat population as well as epizootic outbreaks in human hosts to better inform model- guided fieldwork and public health interventions in Bangladesh.
Mason N McLary
|Location of Publication||New Haven, Connecticut|