Epizootics of yellow fever in Venezuela (2004-2005): An emerging zoonotic disease

Epidemics and epizootics of yellow fever (YF) have been occurring in the border area of eastern Colombia and western Venezuela since 2003; for this reason many epidemiological control measures were adopted by the Ministry of Health (MOH) trying to prevent their spreading. These activities included monkey deaths surveillance as well as immunization of susceptible individuals with YF vaccine. In this setting, we analyzed epidemiological and epizootical issues related to YF in Venezuela during 2004-2005. In this period, YF epizootics occurred initially without geographical links to the 2003 outbreaks (which occurred at the Southern Maracaibo lake epizootic wave), but in relation with the Guayana epizootic wave; beginning in Monagas state and then affecting Anzoátegui, Guárico, and Sucre states. Just months later, Apure was also affected. Mérida and Táchira also report epizootics for the end of 2004. This year concluded with 15 human deaths due to YF and more than 100 howler monkey deaths. In the same year, 715 suspected cases were investigated confirming YF in 0.7% of them. For these reasons, between 2002 and 2004, Venezuela's MOH has vaccinated approximately 1.9 million people in areas considered to be enzootic. The country's goal for 2006 is to have 7 million people residing in high-risk cities and towns vaccinated, and in this way, preventing and controlling this emerging zoonotic disease.