A case of natural infection with Dirofilaria immitis in a coati (Nasua narica) from Mexico.

This paper aims to describe the natural infection with Dirofilaria immitis in Nasua narica (white-nosed coati) from Yucatán, Mexico. Two carcasses of N. narica were collected on a highway that crosses through a dense forest with patches used for agriculture and livestock activities. We performed necropsies, and two female adult nematode parasites from the heart of one specimen were collected and preserved for their molecular identification using a conventional PCR directed at a fragment of the small subunit (18S) ribosomal RNA (18S-rRNA) gene. Bioinformatic analysis showed a similarity of 99 % with three sequences from D. immitis (two from Japan). Additionally, we performed a phylogenetic tree with the recovered sequence. All these analyses showed that D. immitis is present in N. narica from Mexico. The transmission of D. immitis toward populations of Nasua sp. may be due to indirect and accidental contact with domestic dogs or wild canids that share the same environment.

Factors affecting carriage and intensity of infection of Calodium hepaticum within Norway rats (Rattus norvegicus) from an urban slum environment in Salvador, Brazil.

Urban slum environments in the tropics are conducive to the proliferation and the spread of rodent-borne zoonotic pathogens to humans. Calodium hepaticum (Brancroft, 1893) is a zoonotic nematode known to infect a variety of mammalian hosts, including humans. Norway rats (Rattus norvegicus) are considered the most important mammalian host of C. hepaticum and are therefore a potentially useful species to inform estimates of the risk to humans living in urban slum environments. There is a lack of studies systematically evaluating the role of demographic and environmental factors that influence both carriage and intensity of infection of C. hepaticum in rodents from urban slum areas within tropical regions. Carriage and the intensity of infection of C. hepaticum were studied in 402 Norway rats over a 2-year period in an urban slum in Salvador, Brazil. Overall, prevalence in Norway rats was 83% (337/402). Independent risk factors for C. hepaticum carriage in R. norvegicus were age and valley of capture. Of those infected the proportion with gross liver involvement (i.e. >75% of the liver affected, a proxy for a high level intensity of infection), was low (8%, 26/337). Sixty soil samples were collected from ten locations to estimate levels of environmental contamination and provide information on the potential risk to humans of contracting C. hepaticum from the environment. Sixty percent (6/10) of the sites were contaminated with C. hepaticum. High carriage levels of C. hepaticum within Norway rats and sub-standard living conditions within slum areas may increase the risk to humans of exposure to the infective eggs of C. hepaticum. This study supports the need for further studies to assess whether humans are becoming infected within this community and whether C. hepaticum is posing a significant risk to human health.

First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana) from Yucatan, Mexico.

Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13) in brains. Positive amplicons were sequenced for analysis, this produced results similar to T. gondii with identity and coverage values of 98% and 96-100%, respectively. This study presents the first molecular evidence of the circulation of T. gondii in D. virginiana from Mexico.