Clusters of Nipah virus infections were detected at different locations in Malaysia from September 1998 through May 1999. One area of Malaysia that was studied extensively during this time was the Port Dickson district, located in the state of Negeri Sembilan on the west coast of peninsular Malaysia. Epidemiologists recognized a higher prevalence of Nipah infection among pig farmers in this area and collected data from people living and working on farms in Port Dickson to understand the source of the infection. They collected the data from two groups: 1. patients: individuals with encephalitis and evidence of Nipah infection from lab studies
2. controls: individuals who did not have any evidence of disease and came from farms that had some cases of
Nipah virus infection but no reports of encephalitis
1. Occupations* and living arrangements for people in the Port Dickson study
Variable Patients (n = 97) Controls (n = 147)
Pig Farmer/Owner 86 142
Housewife 3 1
Student 9 10
Lived on a pig farm 72 113
Worked on a pig farm 91 147
Epidemiology of Nipah Virus
2. Percentage of people in this study who reported illness among other animals on their farm
Variable Patients Controls
Dogs 87% 76%
Cats 64% 62%
Rats 80% 77%
Chickens 78% 73%
Bats 19% 19%
3. Percentage of infected people in this study who reported an increase in sick/dying animals on their farm
Variable Patients Controls
Pigs 59% 24%
Dogs 25% 8%
Cats 12% 9%
Rats 9% 5%
Chickens 11% 2%
Bats 0% 0%
1. Using the data in Table 1, make a prediction about the source of the Nipah virus outbreak in Port Dickson,
Malaysia. Summarize the data that support your prediction.
2. What actions might you take to prevent further spread of this disease?
3. Which animal species in this study would you test for Nipah virus antibodies? Why?
4. Based on the data above, which animal species was least affected by Nipah virus infection?