Molecular survey for cyst-forming coccidia (Toxoplasma gondii, Neospora caninum, Sarcocystis spp.) in Mediterranean periurban micromammals.

Rodents and other micromammals constitute important reservoirs of infectious diseases; their role in the life cycle of apicomplexan parasites such as Toxoplasma gondii, Neospora caninum, and Sarcocystis spp. still needs clarification. In the present study, we analyzed by PCR and Sanger sequencing methods the presence of specific parasite DNA within brain and heart tissues of 313 individuals of five synanthropic small mammal species (Apodemus sylvaticus, Mus spretus, M. musculus, Rattus rattus, and Crocidura russula) collected in Barcelona metropolitan area (NE Spain). In addition, PCR-RFLP and microsatellites were also used as tools for genotypic characterization of T. gondii and N. caninum, respectively. Specific DNA of T. gondii, N. caninum, and Sarcocystis spp. was detected in 0.3% (n = 1), 1.3% (n = 4), and 3.8% (n = 12) of the animals, respectively. No mixed infections were observed. Crocidura russula stood out as the main host for Sarcocystis spp. Toxoplasma gondii-specific DNA detected in a house rat was genetically characterized by PCR-RFLP, presenting type II and III alleles (SAG1 [II], SAG3 [II], GRA6 [II], c22-8 [III], Apico [III]). Also, unsuccessful DNA sequencing and microsatellite typing were attempted in N. caninum-positive samples, which suggested a lack of PCR specificity and open avenues to speculate the host competence of rodents for N. caninum. Likewise, Sarcocystis spp. identity was studied by alignment and phylogenetic analyses of cox1 and 28S rRNA sequences from the 14 positive samples. It resulted in at least three unknown organisms closely similar (95.7-100% cox1-sequence homology) to Sarcocystis pantherophisi from the Eastern rat snake (Pantherophis alleghaniensis) (KU891603), suggesting together with 28S rRNA sequences analyses, three Sarcocystis sp. with a life cycle conformed by rodents as intermediate host (IH) and snakes as definitive hosts (DH) infecting the periurban micromammals surveyed. Prevalence figures found in this first survey carried out in Spain agree with other international studies focused on periurban areas. Further surveys should be conducted in farms and their surroundings in order to unravel the role of wild micromammals in the epidemiology of such protozoan parasites affecting our livestock, and therefore human population.

Factors associated with the prevalence and pathology of Calodium hepaticum and C. splenaecum in periurban micromammals.

Calodium hepaticum (syn. Capillaria hepatica) and Calodium splenaecum (syn. Capillaria splenaecum) are nematodes that infect the liver and spleen, respectively, of mammals. While the host range, distribution, pathology and zoonotic potential of C. hepaticum are well known, very little is known about C. splenaecum. The observed prevalence of these two parasites, the factors associated with prevalence, and the lesions resulting in the different host species were studied in 408 micromammals captured in two periurban areas of Barcelona (NE Spain) from 2011 to 2013. C. hepaticum was found in 4% of 322 wood mice (Apodemus sylvaticus) (with local prevalence up to 16%) and 1 of 2 Norwegian rats (Rattus norvegicus). C. splenaecum was found in 10 % of 38 greater white-toothed shrew (Crocidura russula) (local prevalence up to 30%). Neither parasite was detected in 29 Algerian mice (Mus spretus) and 17 black rats (Rattus rattus). Prevalence of C. hepaticum was significantly higher in wood mice captured in natural areas (6.4%) than those from residential areas (0%), and infected mice were in better body condition. No differences in prevalence were found among age and sex groups, years and seasons. Lesions of hepatic capillariasis in wood mice consisted mainly of mild to moderate multifocal granulomas around degenerating adult parasites and/or eggs, while lesions seen in a rat consisted of multifocal granulomatous hepatitis and bridging fibrosis extending from the necrotic areas caused by the parasites. Splenic lesions found in shrews due to C. splenaecum, representing the first histological description of this parasite, were single nodules that corresponded to finely encapsulated clusters of eggs with adult parasites.