Ehrlichia canis and Hepatozoon spp. in captive tigers in Thailand

Captive wildlife can serve as reservoirs for various tick-borne pathogens for both domestic animals and humans. Ecotourism tiger parks, where tigers (<i>Panthera tigris</i>) engage with humans and other animals, increase the risk of disease transmission. This study aimed to investigate the infection rate, co-infection patterns, and associated risk factors of tick-borne pathogens (<i>Ehrlichia</i>, <i>Hepatozoon</i>, and <i>Babesia</i>) in captive tigers in Thailand. Blood samples were collected from 100 tigers and analyzed using multiplex PCR to detect the presence of three genera of tick-borne pathogens. The overall infection rate at least one tick-borne pathogen was 17 % (17/100). <i>Ehrlichia canis</i> was the most common, affecting 15 % (15/100) of the tigers, followed by <i>Hepatozoon</i> spp. [5 % (5/100)], with no detected <i>Babesia</i> spp. infection. <i>Ehrlichia canis</i> and <i>Hepatozoon</i> spp. co-infections were confirmed in 3 % (3/100) of the cases. Infection rates were examined according to sex and age. Female tigers exhibited a higher infection rate (22.22 % (10/45)) than males (12.73 % (7/55)), though this difference was not statistically significant (p = 0.209). Age was a significant factor, with older tigers showing higher infection rates (p < 0.001). Co-infections were observed in tigers older than seven years. All infected tigers, single or co-infected, commonly exhibited hyperproteinemia, anemia, and elevated creatinine levels in their blood. All pathogens identified in this study posed health risks to captive tigers, with infection rates primarily influenced by age. <i>Ehrlichia canis</i> poses the highest health risk for captive tigers in Thailand. These findings underscore the importance of routine health monitoring and effective tick control strategies to protect these endangered animals.