Zoonotic Disease Spillover Lecture Given By Dr. John Openshaw

By CLAYTON LAUPUS                April 15, 2016

Dr. John Openshaw, Instructor of Infectious Diseases and Geographic Medicine at the Stanford University School of Medicine, visited Memorial Sloan Kettering Cancer Center on April 1st to give a lecture titled Zoonotic Disease Spillover: Characterizing Risk, Pathogen Discovery, and Threat Mitigation.  Dr. Openshaw is currently conducting research in Bangladesh, China, and Costa Rica, trying to understand the ecology that enables viruses to jump from animals to humans and better define the steps that are required to stop the emergence of these pathogens.

Zoonotic diseases account for 60% of emerging diseases including some that have caused global health emergencies such as Ebola and, more recently, Zika. Dr. Openshaw discussed ways to identify emerging pathogens. One way is to test wild animals for pathogens, which can give a large view of what pathogens exist, but would not indicate which pathogens may affect humans.  The better way to identify emerging pathogens starts by looking at an at risk population, and then testing for pathogens based on risk stratification. Next there is an assessment of the behaviors which make people susceptible, and finally mitigation. 

Dr. Openshaw’s work in Bangladesh focuses on the Nipah virus. Nipah virus in humans can cause acute respiratory syndrome or encephalitis (inflammation of the brain).  Bangladesh’s tropical environment, high human density, and poverty levels make it an important place to study zoonotic diseases. There is a known background of zoonotic diseases, with frequent Nipah virus outbreaks almost yearly. Nipah virus which originates in Pteropid fruit bats is usually transmitted to humans through date palm sap, a popular sugary drink in Bangladesh. To collect date palm sap a cut is made in the tree trunk and over a few days sap will collect in a pot below the cut.  The sap is enjoyed by fruit bats that salivate and urinate in the stream of sap, causing Nipah virus spillover.  Dr. Openshaw’s research in Bangladesh has two components, a hospital survey and a village survey.  The hospital survey starts with acutely ill patients, performs a zoonotic exposure assessment, and then completes sample and data collection, and finally pathogen discovery.  The village survey identifies healthy villagers with high zoonotic exposure, has them complete a questionnaire about their environmental conditions and behavior, and then compares these villagers against those who have become sick.  The goal is to identify what specific behaviors as well as general trends lead to infection, and determine how they can be better avoided.

This work to increase our understanding of the ecology that enables viral spillover events and better outlining how to stop the emergence of zoonoses is crucial to global health.  As has been seen with outbreaks such as Ebola and currently Zika, the threats posed by zoonotic diseases to the global community are real and best addressed before they become pandemic.