Hepato- and nephro-toxicity of coumatetralyl rodenticide in some wild rat species

Coumatetralyl (COM) is an anticoagulant rodenticide absorbed quickly after oral dosing. It causes rodent’s death due to internal or external bleeding after complete depletion of plasma vitamin K-dependent coagulation factors. The present study aimed was to shed light on metabolic alterations as the potential hepato- and nephrotoxicity caused by ¼ LD50 COM in Rattus rattus, Arvicanthis niloticus, and Geribellus geribellus wild rat species. Elevation in plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, total free amino acids, and erythrocyte lysate glucose-6-phosphate dehydrogenase levels were observed in COM fed rats. Furthermore, plasma creatinine and urea and free hemoglobin levels increased following COM exposure in the challenged rats compared with that in the control ones. It was concluded that ¼ LD50 COM induced hepato- and nephron-toxicity in the fighting rodents.

The prevalence of Trichinella spiralis in farmed minks (Neovison vison) associated with exposure to wild rats (Rattus norvegicus) in Shandong province, China

Background Both of American mink (Neovison vison) and wild rat (Rattus norvegicus) is considered reservoir hosts carrying many endoparasites. Trichinella is a successful parasitic nematode including nine species and three genotypes with a worldwide distribution. However, little is known about the prevalence of Trichinella infection in mink (Neovison vison) and rat (Rattus norvegicus) in China.Methods In total, 289 muscle samples of minks and 102 rat carcasses were collected between April 2017 and December 2019 in Weihai city of Shandong province, China. The food of minks including chicken skeleton and mashed marine products was also collected at 3 batches. All the samples were used to examine for the appearance of Trichinella by the pooled artificial HCl-pepsin digestion method. The isolates from minks and rats were identified as T. spiralis by multiplex PCR. Then, the phylogenetic tree was constructed based on the sequences of 5S rDNA inter-gene spacer regions.Results Muscle larvae were detected in 20 out of 289 minks (6.92%) and in 2 of 102 wild rats (1.96%), respectively. The intensity of Trichinella in mink samples was ranged from 0.025 to 0.815 lpg, while the larval burden in rats was 0.17 lpg. The isolates from minks and rats were identified as T. spiralis by multiplex PCR. Sequence analysis revealed a 100% identical alignment of the 5S rDNA inter-gene spacer regions from the two isolates. The phylogenetic tree confirmed the two isolates from minks and rats belonging to T. spiralis based on analysis of the 5S rDNA inter-gene spacer sequence.Conclusions The present study represents the first report of T. spiralis infection in American mink (Neovison vison) and wild rat (Rattus norvegicus) from Shandong province, China. The farmed minks would be vulnerable to Trichinella infection through exposure to the wild rats. The prevalence of T. spiralis in wild rats may raise a public health concern for the potential zoonotic risk for the domestic animals.

Identification of Cryptosporidium viatorum XVa subtype family in two wild rat species in China

Background Cryptosporidium viatorum is a minor Cryptosporidium pathogen in humans. Currently, there is limited information regarding the prevalence and genotypes of C. viatorum in animals in China. Methods In this study, 228 faecal samples were collected from two wild rat species (Leopoldamys edwardsi and Berylmys bowersi) in Chongqing Municipality and Guangdong Province, China. These specimens were analyzed for C. viatorum and then subtyped it using PCR and sequence analysis of the small subunit ribosomal RNA (SSU rRNA) and 60-kilodalton glycoprotein (gp60) genes, respectively. Results A total of 25 (11.0%) faecal samples were tested positive for C. viatorum by SSU rRNA assay. Of these samples, 4 (3.6%) came from L. edwardsi and 21 (18.0%) from B. bowersi. Of the 25 C. viatorum-positive samples, 17 were successfully amplified at the gp60 gene locus, which represented four subtypes belonging to two subtype families, including XVa (XVaA6, XVaA3g, XVaA3h) and XVc (XVcA2G1). Phylogenetic analysis based on the gp60 amino acid sequences indicated that all of the C. viatorum isolates grouped together, supporting the conclusion that C. viatorum from the wild rats represent two subtype families. Conclusions These results indicate an occurrence of C. viatorum XVa subtype family from rats which is genetically identical to those found in humans. Our findings suggest that wild rats may be a potential source of human cryptosporidiosis.

Domestication and the Role of Social Play on the Development of Sociocognitive Skills in Rats

Several studies on rats and hamsters, across multiple laboratories, have shown that limiting play in the juvenile period leads to adults that have physiological and anatomical changes in the medial prefrontal cortex (mPFC) and reduced socio-cognitive skills. Peers raised with playful peers have better socio-cognitive skills than animals raised with adult partners. Using Long Evans hooded rats - a commonly used domesticated strain - this relationship has been replicated multiple times. However, when the same paradigm was used with laboratory-reared wild rats, no differences were found between rats reared with peers and ones reared with adults. It has been shown that the key play-generated experiences involved are those related to actively wrestling with a partner and turn taking (as measured by role reversals), which give both partners opportunity to gain the advantage during play fighting. In the present study, we tested the hypothesis that wild rat adults provide juveniles more such experiences than do adult Long Evans rats. The asymmetry in the play interactions in adult-juveniles pairs was compared between the two strains. As predicted, wild rat adults initiated more play with the juveniles, wrestled more and provided more opportunities for role reversals. The findings thus support the hypotheses for the observed strain differences in the effects of rearing condition on the mPFC.