Free-living snakes as a source and possible vector of Salmonella spp. and parasites

Abstract

Free-living snakes may carry a broad range of pathogens that differ considerably by geographical locations and source species. The biological role of wildlife snakes for transmission of bacteria and helminths is hardly explored. The purpose of the study was a snapshot on the zoonotic agents load in free-living snakes found dead in a landscape park in central Poland. A total of 16 dead free-living snakes identified as European grass snake (Natrix natrix, N = 15) and a smooth snake (Coronella austriaca, N = 1) were tested. Abdominal organs were used for bacteriological testing, whereas, parasites were searched for in the remaining carcasses. Fourteen (87.5 %) individuals were positive for Salmonella spp., whereas, trematodes were found in 13 out of 16 samples (81.3 %). A total of 33 isolates representing 11 Salmonella serovars or antigenic forms were observed with Salmonella enterica subsp. diarizonae (IIIb) 38:r:z being the most frequent. The trematodes were recognized as Alaria alata mesocercariae (Distomum musculorum suis, DMS). Additionally, unidentified nematodes were detected in four samples. No Yersinia spp. and Mycobacterium spp. were found. The results indicate huge burden of Salmonella spp. and muscle parasites carriage by snakes present in the natural environment and indicate possible zoonotic and epidemiological impact. It justifies our concept of freeliving snakes as possible source and vector of pathogens, especially for omnivores and scavengers foraging on snake corpses. Finding of rare and diverse Salmonella serovars and unidentified nematodes proves the need for in-depth studies and systematic approach to reveal the role of freeliving reptiles in epidemiology of infectious agents.

Diversity of helminths in polish reptiles: a review

“…Only the presence of unidentified nematodes was reported in one individual from the Gostynin-Włocławek Landscape Park during a survey on the detection of Salmonella spp. in native snakes (Zając et al 2016). This snake is a secretive and notoriously difficult species to detect in the field (Profus et al 2018), thus data on the helminths infecting this species throughout Poland and other Central European countries are scarce.…”

In vitro virulence characteristics of rare serovars of Salmonella enterica isolated from sand lizards (Lacerta agilis L.)

“…enterica serovar Schleissheim (n = 5), S. Abony (n = 2) and S . Telhashomer (n = 1), according to EN ISO 6579:2002/A1:2007 and the presence of the invA gene (Zając et al 2016 ).…”

Salmonella and Antimicrobial Resistance in Wild Rodents—True or False Threat?

“…The role of food-producing animals in the spread of AMR and Salmonella along the food chain has been confirmed by numerous monitoring programs [ 3 , 6 , 7 , 8 ]. Several reports indicate the contribution of wildlife in AMR and Salmonella dissemination [ 9 , 10 , 11 ]. However, due to the lack of large-scale research, the importance of wildlife as a reservoir of AMR and zoonotic pathogens still seems to be insufficiently recognized.…”