Small rodents as paratenic or intermediate hosts of carnivore parasites in Berlin, Germany

Abstract

Rodents are important intermediate and paratenic hosts for carnivore parasites, including the important zoonotic agents Toxoplasma, Echinococcus and Toxocara. Monitoring of such parasites in rodents can be used to detect increasing risks for human and veterinary public health. Rodents were trapped at four sites in Berlin, two near the city center, two at the periphery. PCRs were conducted to detect Coccidia (target ITS-1) and specifically Toxoplasma gondii (repetitive element) in brain and ascarids (ITS-2) in muscle or brain tissue. During necropsies, metacestodes were collected and identified using ITS-2 and 12S rRNA PCRs. An ELISA to detect antibodies against Toxocara canis ES antigens was performed. Within the 257 examined rodents, the most frequently observed parasite was Frenkelia glareoli predominantly found in Myodes glareolus. T. gondii was only detected in 12 rodents and Microtus spp. (although strongly underrepresented) had a significantly increased chance of being positive. Neither Echinococcus nor typical Taenia parasites of dogs and cats were found but Mesocestoides litteratus and Taenia martis metacestodes were identified which can cause severe peritoneal or ocular cysticercosis in dogs, primates and humans. Using PCR, the ascarids T. canis (n = 8), Toxocara cati (4) and Parascaris sp. (1) were detected predominantly in muscles. Seroprevalence of T. canis was 14.2% and ELISA was thus more sensitive than PCR to detect infection with this parasite. Non-parametric multidimensional scaling and cluster analysis revealed that parasite communities could be grouped into an urban and a peri-urban cluster with high frequency of ascarid-positive rodents in urban and high frequency of F. glareoli in peri-urban sites. Prevalence rates of parasites in rodents with potential impact for human or veterinary public health are considerable and the monitoring of transmission cycles of carnivore parasites in intermediate rodent hosts is recommended to estimate the health risks arising from wild and domesticated carnivores.

A comparative study of helminths of raccoon dogs (Nyctereutes procynoides) and red foxes (Vulpes vulpes) sharing the same territory

“…Under natural conditions it is most likely that adult wild carnivores become infected via rodents functioning as paratenic hosts. There is a good reason for this since T. canis DNA was detected in 8 (3.1%) out of 257 mice and voles captured in outskirt districts of Berlin city with high fox densities and, the T. canis ELISA seroprevalence in these small rodents added up to 14.2% [42]. The transplacental and transmammary infection explains why juvenile hosts in our study showed higher ascarid prevalence and burdens.…”

“…Mesocestoides tetrathyridia were found in mice and voles in Germany in the same low percentage as those of T. polyacantha and T. crassiceps [36]. In a more recent study, tetrathyridia were detected in six out of 257 small rodents in Berlin [42]. Considering this high prevalence in both raccoon dogs and red foxes, it has to be assumed that the life cycle of M. litteratus differs from the those of above mentioned Taenia species.…”

Seroprevalence of Echinococcus spp. and Toxocara spp. in Invasive Non-native American Mink

“…The difficulties with finding larvae specimens in the tissues of intermediate/paratenic hosts (such as hu- mans) have led to the development of serological tests for use in toxocarosis diagnostics (Dziemian et al 2008;Fillaux and Magnaval 2013). Used on rodent hosts, these methods deduced a 14.2% T. canis seroprevalence and showed ELISA to be more sensitive than PCR for detecting infection with the parasite (Krucken et al 2017). Studies using immunodiagnostic methods have been carried out worldwide (Krucken et al 2017;Li et al 2017;Lassen et al 2016;Klockiewicz et al 2019a).…”

“…Used on rodent hosts, these methods deduced a 14.2% T. canis seroprevalence and showed ELISA to be more sensitive than PCR for detecting infection with the parasite (Krucken et al 2017). Studies using immunodiagnostic methods have been carried out worldwide (Krucken et al 2017;Li et al 2017;Lassen et al 2016;Klockiewicz et al 2019a). Serological analysis also allows the easy detection of mixed infections in hosts.…”

“…antibodies in the muscle juice of American mink-using a somatic antigen from Echinococcus multilocularis protoscoleces and excretorysecretory (E/S) antigen of Toxocara canis larvae-was conducted with an indirect enzyme-linked immunosorbent assay (iELISA) according to Havasiová-Reiterová et al (1995) with slight modifications. Toxocara canis excretorysecretory antigen (E/S antigen) is highly specific, can detect both T. canis and T. cati antibodies, and shows no crossreactivity with other ascarid species (Cuellar et al 1995;Krucken et al 2017). Similarly, Echinococcus multilocularis antigen can detect both E. multilocularis and E. granulosis antibodies.…”