Phylogenetic and ecological factors affecting the sharing of helminths between native and introduced rodents in Central Chile.

In order to analyse the effect of hosts' relationships and the helminthic load on the switching of parasites between native and introduced hosts, we sampled rodents belonging to two suborders from Central Chile. We compared the number of helminthic species shared between murids (introduced) and cricetid (native, same suborder) rodents to those shared between murids and hystricomorphs (native, different suborder), and we assessed the association between parasitic presence, abundance and geographical dispersion in source hosts to the presence and abundance in recipient hosts. Introduced rodent species shared more helminth species with cricetid rodents than with non-cricetids. Presence and abundance in recipient hosts was not associated with the prevalence and mean abundance in source hosts' population. The mean abundance of parasites in source hosts throughout the territory and wider dispersion was positively associated with the likelihood of being shared with a recipient host. Closer relationships between native and introduced hosts and high parasitic abundance and dispersion could facilitate host switching of helminths between native and introduced rodents. This work provides the first documentation of the importance of parasitic abundance and dispersion on the switching of parasites between native and introduced hosts.

Trypanosoma cruzi DNA in Desmodus rotundus (common vampire bat) and Histiotus montanus (small big-eared brown bat) from Chile.

The protozoan Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted by infected feces or consumption of blood-sucking triatomine insects to several mammalian orders including Chiroptera. In Chile, the distribution of several insectivorous and one hematophagous bat species overlaps with those of triatomine vectors, but the T. cruzi infection status of local chiropterans is unknown. In 2018, we live-captured bats from two protected areas in Chile to collect plagiopatagium tissue, feces and perianal swab samples, in search for T. cruzi-DNA by real time PCR assays using species-specific primers. In Pan de Azúcar island (∼26°S), we examined a roost of Desmodus rotundus (common vampire bat) and sampled tissue from 17 individuals, detecting T. cruzi-DNA in five of them. In Las Chinchillas National Reserve (∼31°S), we examined two roosts of Histiotus montanus (small big-eared brown bat), collecting feces or perianal swab samples from eight individuals, detecting T. cruzi-DNA in four of them. This is the first report of T. cruzi-DNA evidence in bat species from Chile. Both vector-borne and oral transmission are potential infection routes that can explain our results. Further investigation is needed for a better understanding of the role of bats in the T. cruzi transmission cycle.

Lizards and rabbits may increase Chagas infection risk in the Mediterranean-type ecosystem of South America.

Studies of host-parasite relationships largely benefit from adopting a multifactorial approach, including the complexity of multi-host systems and habitat features in their analyses. Some host species concentrate most infection and contribute disproportionately to parasite and vector population maintenance, and habitat feature variation creates important heterogeneity in host composition, influencing infection risk and the fate of disease dynamics. Here, we examine how the availability of specific groups of hosts and habitat features relate to vector abundance and infection risk in 18 vector populations along the Mediterranean-type ecosystem of South America, where the kissing bug Mepraia spinolai is the main wild vector of the parasite Trypanosoma cruzi, the etiological agent of Chagas disease. For each population, data on vectors, vertebrate host availability, vegetation, precipitation, and temperature were collected and analyzed. Vector abundance was positively related to temperature, total vegetation, and European rabbit availability. Infection risk was positively related to temperature, bromeliad cover, and reptile availability; and negatively to the total domestic mammal availability. The invasive rabbit is suggested as a key species involved in the vector population maintenance. Interestingly, lizard species -a group completely neglected as a potential reservoir-, temperature, and bromeliads were relevant factors accounting for infection risk variation across populations.

Helminthic infection in three native rodent species from a semiarid Mediterranean ecosystem.

Helminth parasites are still not a well-known component of animal biodiversity. In this study, we describe and compare the endoparasite assemblages of three native rodent species from a semiarid Mediterranean ecosystem. A total of eight species of gastrointestinal helminth parasites were detected. The endoparasitic communities of the rodents Phyllotis darwini (5 species), Octodon degus (4 species), and Abrothrix olivaceus (3 species) were described in terms of their prevalence and mean abundance. In addition, endoparasite records by rodent species were submitted to rarefaction analyses to verify sampling robustness and used to compare richness and similarity among rodent species. O. degus presented the highest prevalence and parasitic load, but was of low diversity, while P. darwini presented the highest diversity, but had a low prevalence rate. Conversely, A. olivaceus presented the lowest prevalence and diversity. This study contributes to the existing knowledge of the endoparasitic fauna of rodent species from semiarid Mediterranean zones.

Helminthic infection in three native rodent species from a semiarid Mediterranean ecosystem

Abstract Helminth parasites are still not a well-known component of animal biodiversity. In this study, we describe and compare the endoparasite assemblages of three native rodent species from a semiarid Mediterranean ecosystem. A total of eight species of gastrointestinal helminth parasites were detected. The endoparasitic communities of the rodents Phyllotis darwini (5 species), Octodon degus (4 species), and Abrothrix olivaceus (3 species) were described in terms of their prevalence and mean abundance. In addition, endoparasite records by rodent species were submitted to rarefaction analyses to verify sampling robustness and used to compare richness and similarity among rodent species. O. degus presented the highest prevalence and parasitic load, but was of low diversity, while P. darwini presented the highest diversity, but had a low prevalence rate. Conversely, A. olivaceus presented the lowest prevalence and diversity. This study contributes to the existing knowledge of the endoparasitic fauna of rodent species from semiarid Mediterranean zones.

Resumo Os helmintos parasitas não são um componente ainda bem conhecido da biodiversidade animal. Neste trabalho, descreveu-se e comparou-se as redes de endoparasitas de três espécies de roedores nativos de um ecossistema mediterrâneo semiárido. No estudo foram detectadas um total de oito de espécies de helmintos gastrointestinais parasitas. As comunidades endoparasíticas dos roedores Phyllotis darwini (5 espécies), Octodon degus (4 espécies) e Abrothrix olivaceus (3 espécies) foram descritas por meio da sua prevalência e abundância média. Além disso, os registros de endoparasitas achados nas diferentes espécies de roedores foram submetidos a uma análise de rarefação para verificar a robustez da amostragem, e utilizados para comparar a riqueza e a similaridade entre espécies de roedores. Octodon degus apresentou a maior prevalência e carga parasitária, menor diversidade, enquanto P. darwini apresentou a maior diversidade, mas uma baixa prevalência. Porém, A. olivaceus apresentou a menor prevalência e diversidade de parásitas. Este estudo representa uma contribuição ao conhecimento da fauna endoparasitária das espécies de roedores próprias das zonas semi-áridas do Mediterrâneo chileno.

Helminthic infection in three native rodent species from a semiarid Mediterranean ecosystem / Infecção por helmintos em três espécies de roedores nativos em um ecossistema mediterrâneo

Abstract Helminth parasites are still not a well-known component of animal biodiversity. In this study, we describe and compare the endoparasite assemblages of three native rodent species from a semiarid Mediterranean ecosystem. A total of eight species of gastrointestinal helminth parasites were detected. The endoparasitic communities of the rodents Phyllotis darwini (5 species), Octodon degus (4 species), and Abrothrix olivaceus (3 species) were described in terms of their prevalence and mean abundance. In addition, endoparasite records by rodent species were submitted to rarefaction analyses to verify sampling robustness and used to compare richness and similarity among rodent species. O. degus presented the highest prevalence and parasitic load, but was of low diversity, while P. darwini presented the highest diversity, but had a low prevalence rate. Conversely, A. olivaceus presented the lowest prevalence and diversity. This study contributes to the existing knowledge of the endoparasitic fauna of rodent species from semiarid Mediterranean zones.

Resumo Os helmintos parasitas não são um componente ainda bem conhecido da biodiversidade animal. Neste trabalho, descreveu-se e comparou-se as redes de endoparasitas de três espécies de roedores nativos de um ecossistema mediterrâneo semiárido. No estudo foram detectadas um total de oito de espécies de helmintos gastrointestinais parasitas. As comunidades endoparasíticas dos roedores Phyllotis darwini (5 espécies), Octodon degus (4 espécies) e Abrothrix olivaceus (3 espécies) foram descritas por meio da sua prevalência e abundância média. Além disso, os registros de endoparasitas achados nas diferentes espécies de roedores foram submetidos a uma análise de rarefação para verificar a robustez da amostragem, e utilizados para comparar a riqueza e a similaridade entre espécies de roedores. Octodon degus apresentou a maior prevalência e carga parasitária, menor diversidade, enquanto P. darwini apresentou a maior diversidade, mas uma baixa prevalência. Porém, A. olivaceus apresentou a menor prevalência e diversidade de parásitas. Este estudo representa uma contribuição ao conhecimento da fauna endoparasitária das espécies de roedores próprias das zonas semi-áridas do Mediterrâneo chileno.