Risk of tick-borne arboviruses in Thailand

Abstract

Ticks are known vectors of transmission for a number of infectious viral diseases from wild or domestic animals to humans. Many tick-borne diseases cause severe clinical syndromes such as encephalitis or hemorrhagic fever. Animal carriers of enzootic diseases are often asymptomatic. Within the framework of a program to monitor emerging viral diseases in Southeast Asia, identification of ticks capable of transmitting diseases from animals to man is a prerequisite for epidemiologic study to assess the risk of tick-borne disease. The purpose of this report is to provide an update on the situation based on a study of tick fauna in the central plain area of Thailand and on current knowledge about tick-borne arboviruses in Asia. In addition to an exhaustive inventory of ticks found in Thailand, this study describes the viruses with pathogenic potential that ticks are known to carry and transmit to man. A perusal of the literature allowed initial assessment of the risk for introduction and spread of ticks by bird hosts in Southeast Asia as well as of associated virus.