Epidemiologic and Economic Analysis of Avian Influenza in Nepal

Abstract

Many countries, including Nepal, have been affected with highly pathogenic avian influenza (HPAI) outbreaks. There have been human mortalities in some countries and large numbers of poultry either died or were culled due to HPAI. The overall objective of this thesis was to improve our understanding of the epidemiology and economics of avian influenza (AI), and particularly HPAI, in Nepal.

We determined the seroprevalence of and risk factors for AI virus antibodies presence in ducks in Kathmandu, Nepal. The estimated true prevalence of AI viruses (AIV) antibodies was 27.2% [95% Confidence Interval (CI): 24.6- 29.5]. Age of the ducks was identified as the only risk factor for AIV seropositivity. Ducks older than one year were more likely to be seropositive compared to ducks less than six months of age [Odds Ratio= 2.17 (95% CI: 1.07- 4.39)]. This study provided baseline information about seroprevalence of AIVs in Kathmandu that will benefit further research to differentiate the subtypes of AIVs circulating in Kathmandu.

We also evaluated alternatives to the current control program (CCP) for HPAI in Nepal. The considered alternatives were: (i) absence of control measures (ACM) and (ii) vaccinating 60% of the domestic poultry flock twice per year. Cost-benefit analysis approach was used to evaluate the economic feasibility of the programs. In terms of the benefit-cost ratio, our findings indicated that there is a return of 1.96 dollars for every dollar spent in the CCP compared to ACM. The net present value of the CCP versus ACM was US$ 989,918. The vaccination program yielded a return of 2.41 dollars for every dollar spent when compared to the CCP. The net present value of vaccination versus implementing the CCP was US$ 13,745,454. These results support a continued investment into the CCP rather than ceasing to implement government regulated control measures and suggest that vaccination may be an even better control alternative.

In summary, our studies have highlighted the value of epidemiologic and economic analysis in research of AI. Our results are expected to lead to an improved understanding and awareness of AI in Nepal and to formulation of better control strategies.