Epidemiology and control of avian influenza H5N1 virus in Thailand

Abstract

The HPAI epidemic in Asia in 2003 has caused serious losses through severe morbidity and mortality in poultry and through losses in human life. In addition, control measures and loss of life hood within the large backyard farming community caused large economic losses both on the national and community level. The recurrence of HPAI worldwide in various poultry industry systems in the last decade asks for more research effort on the effect of monitoring and control options, specific for the situation of each poultry system. Optimal control options are of more vital importance for HPAI than for various other infectious animal diseases, because of the zoonotic potential of HPAI. The next human Influenza pandemic might originate from a next HPAI outbreak. The overall objective of this thesis was to investigate epidemiological features, risk factors, and transmission dynamics of H5N1 avian influenza in Thailand. The specific objectives of the studies described in this thesis are: - To perform a descriptive analysis of the 2004 HPAI epidemic in Thailand, - To quantify the within-flock transmission of HPAI H5N1 virus in infected poultry flocks in Thailand, - To investigate ecologic risk factors of the clusters of HPAI H5N1, and - To study risk factors associated with HPAI H5N1 outbreaks in poultry units Knowledge gained from this thesis emphasized that epidemiological analysis provides insight information of past epidemics which can be used for improving control measures and preventing the future epidemic.