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The aim of this paper was to study the occurrence of helminths in Mus musculus and Rattus rattus from urban, suburban and rural settlements in Yucatán, Mexico; and to analyse the host factors (e.g. sex) related to helminths’ distribution. Helminths in a total of 279 rodents were surveyed by visual examination of the liver for metacestodes and faecal examination for helminth eggs using the formalin-ethyl acetate sedimentation technique. The cestodes Hydatigera taeniaeformis (metacestodes detected in the liver) and Hymenolepis diminuta, and the nematodes Aspiculuris sp., Nippostrongylus brasiliensis, Syphacia muris, Syphacia obvelata, and Trichuris muris were identified. In M. musculus, the prevalence of infection with T. muris and H. taeniaeformis was higher in the rural village compared to those in the suburban neighbourhood. For R. rattus, a higher prevalence of infection with H. diminuta was found in the urban site compared to that in the suburban site. This study reports the occurrence of H. diminuta among rodents living in close proximity to humans, representing a potential public health risk. In addition, this survey increases our understanding of dynamic transmission among intestinal helminths recorded in Yucatán, Mexico.

Toxoplasma gondii is an obligate intracellular parasite recognized as the etiological agent of Toxoplasmosis, a zoonotic disease endemic in different countries worldwide. In Mexico, the disease is recognized as a human and animal health problem. T. gondii sporozoites have the capacity of been released from the gut lumen and infect several tissues, including kidneys. Rodents have been identified as intermediate hosts of T. gondii; nevertheless, no previous reports exist in Yucatan, Mexico, about their role in the infectious cycle. A total of 187 specimens (130 Mus musculus and 57 Rattus rattus) were studied. Total DNA was extracted from renal tissue and was utilized in the identification of T. gondii with the end-point Polymerase Chain Reaction (PCR) method. Six positive products were purified and sequenced in order to confirm and validate the results through the BLAST Sequence Analysis Tool. The PCR provided a global positivity of 5.34% (10/187). The BLAST analysis found a direct homology for T. gondii with identities and coverage of 96-98% and 98-100%, respectively. Our results confirm the role of M. musculus and R. rattus in the biological cycle of T. gondii and offer knowledge of the parasite transmission in intermediary hosts of the region. Toxoplasma gondii est un parasite intracellulaire obligatoire et l'agent causal de la toxoplasmose, une zoonose endémique dans différents pays. Au Mexique, la maladie est reconnue comme un problème de santé humaine et animale. Les sporozoïtes de T. gondii peuvent être libérés de la lumière intestinale et infecter différents tissus, dont les reins. Bien que les rongeurs soient reconnus comme des hôtes intermédiaires de T. gondii, il n'existe aucune étude sur leur rôle dans le cycle d'infection dans la région du Yucatan au Mexique. Au total, 187 spécimens (130 Mus musculus et 57 Rattus rattus) ont été étudiés. L'ADN total a été extrait du tissu rénal et utilisé pour l'identification de T. gondii par PCR. Six amplicons ont été purifiés et séquencés afin de confirmer et valider les résultats en utilisant l'outil d'analyse de séquences BLAST. La PCR a donné une positivité globale de 5.34% (10/187). L'analyse BLAST a donné une homologie directe avec T. gondii, avec des identités et couvertures de 96-98% et 98-100%, respectivement. Nos résultats confirment le rôle de M. musculus et R. rattus dans le cycle biologique de T. gondii et apportent de la connaissance quant à la transmission du parasite dans des hôtes intermédiaires de la région. [ABSTRACT FROM AUTHOR]