Distribution of Salmonella spp. and serovars isolated from captive reptiles in four zoos of the Zoological Park Organization, Thailand, between 2017 and 2018

Abstract

Salmonellosis is the main reason for food borne diseases in many countries globally and it has been found that reptiles are carriers of the disease. Therefore, this study was performed to determine the distribution of Salmonella spp. and their serovars from reptiles in zoos in Thailand between 2017 and 2018. A total of 257 reptile samples were collected from four zoos which are Dusit (128 samples), Chiangmai (32 samples), Songkhla (34 samples) and Nakhonratchasima (63 samples). Salmonella was isolated and identified, serotyping of those isolates was investigated using a panel of Salmonella antisera and serotypes were characterized according to the Kauffman-White classification scheme. Salmonella isolates were found in 93 (36.19%) of all samples, 51 (39.84%), 25 (39.68%), 9 (28.13%) and 8 (23.53%) isolates in Dusit, Nakhonratchasima, Chiangmai, and Songkhla, respectively. Salmonella was found mostly in snakes (70.13%) followed by lizards (57.57%) and turtles (13.70%). Sixty-two Salmonella isolates were selected for serotyping study and there were 4 subspecies and 32 serovars, S. diarizonae being the most common followed by S. enterica, S. houtenae, and S. arizonae, respectively. Dusit was the most common variety with 18 serovars followed by Nakhonratchasima (10 serovars), Songkhla (5 serovars) and Chiangmai (4 serovars). Salmonella from snakes showed the greatest diversity of serovars. The study showed that these reptiles were the sources of Salmonella spp. especially S. enterica which causes disease in humans with a high ratio (43.55%). This revealed a risk of Salmonella infection. It is necessary to carefully observe and emphasize the risk of contamination within the zoos in order to prevent the spread of Salmonella from reptiles to other animals and the community.