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A new species of coccidian, Isospora guaxi n. sp., and Isospora bellicosa Upton, Stamper & Whitaker, 1995 (Protozoa: Apicomplexa: Eimeriidae) are recorded from red-rumped caciques Cacicus haemorrhous (L.) in the Parque Nacional do Itatiaia, Brazil. Isospora guaxi n. sp. has sub-spheroidal oöcysts, measuring on average 30.9 × 29.0 µm, with smooth, bi-layered wall c.1.9 µm thick. Micropyle and oöcyst residuum are absent, but a polar granule is present. Sporocysts are ellipsoidal, measuring on average 19.3 × 13.8 µm. Stieda body is knob-like and sub-Stieda body is prominent and compartmentalized. Sporocyst residuum is composed of scattered granules. Sporozoites are vermiform, with one refractile body and a nucleus. Isospora bellicosa has sub-spheroidal to ovoidal oöcysts, measuring on average 27.1 × 25.0 µm, with smooth, bi-layered wall c.1.5 µm thick. Micropyle and oöcyst residuum are absent, but one or two polar granules are present. Sporocysts are ellipsoidal, measuring on average 18.1 × 10.9 µm. Stieda body is knob-like and sub-Stieda body is rounded to rectangular. Sporocyst residuum is composed of a cluster of compact or diffuse granules. Sporozoites are vermiform, with one refractile body and a nucleus. Isospora bellicosa was originally described from the Peruvian meadowlark Sturnella bellicosa deFilippi, a trans-Andean icterid which is allopatric with the cis-Andean C. haemorrhous. Therefore, in conclusion, this current study reveals the dispersion of coccidia from Icteridae across the Andes Mountains, besides describing the sixth isosporoid coccidium infecting an icterid bird.

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BACKGROUND: Urbanization can strongly impact the physiology, behavior, and fitness of animals. Conditions in cities may also promote the transmission and success of animal parasites and pathogens. However, to date, no studies have examined variation in the prevalence or severity of several distinct pathogens/parasites along a gradient of urbanization in animals or if these infections increase physiological stress in urban populations. METHODOLOGY/PRINCIPAL FINDINGS: Here, we measured the prevalence and severity of infection with intestinal coccidians (Isospora sp.) and the canarypox virus (Avipoxvirus) along an urban-to-rural gradient in wild male house finches (Haemorhous mexicanus). In addition, we quantified an important stress indicator in animals (oxidative stress) and several axes of urbanization, including human population density and land-use patterns within a 1 km radius of each trapping site. Prevalence of poxvirus infection and severity of coccidial infection were significantly associated with the degree of urbanization, with an increase of infection in more urban areas. The degrees of infection by the two parasites were not correlated along the urban-rural gradient. Finally, levels of oxidative damage in plasma were not associated with infection or with urbanization metrics. CONCLUSION/SIGNIFICANCE: These results indicate that the physical presence of humans in cities and the associated altered urban landscape characteristics are associated with increased infections with both a virus and a gastrointestinal parasite in this common songbird resident of North American cities. Though we failed to find elevations in urban- or parasite/pathogen-mediated oxidative stress, humans may facilitate infections in these birds via bird feeders (i.e. horizontal disease transmission due to unsanitary surfaces and/or elevations in host population densities) and/or via elevations in other forms of physiological stress (e.g. corticosterone, nutritional).

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A growing body of literature reveals that the interactions among the parasite community may be strong and significant for parasite dynamics. There may be inter-specific antagonistic interactions as a result of competition and cross-effective immune response, or synergistic interactions where infection by one parasite is facilitated by another one, either by an impoverishment of the host's defenses, parasite-induced selective immunosuppression, or trade-offs within the immune system. The nature of these interactions may depend on how related are the parasite species involved. Here we explored the presence of associations among gastrointestinal parasites (coccidia and helminths) in natural populations of two wild mammal species, the capybara (Hydrochoerus hydrochaeris) and the guanaco (Lama guanicoe). The associations explored were between the oocyst outputs of a selected Eimeria species and the other coccidia of that parasite community, and between Eimeria spp. and the predominant nematodes. The statistical analysis included adjustment for potential confounders or effect modifiers. In guanacos, the prevailing interactions were synergistic among the coccidia and between coccidia and nematodes (Nematodirus spp.). However, in capybaras, the interaction between nematodes (Viannaiidae) and Eimeria spp. depended on environmental and host factors. The relationship was positive in some circumstances (depending on season, year, sex, or animal size), but it appeared to become antagonistic under different scenarios. These antagonist interactions did not follow a particular seasonal pattern (they occurred in autumn, spring, and summer), but they were predominantly found in females (when they depended on sex) or in 2010 and 2011 (when they depended on the sampling year). These results suggest that the relationship between coccidia and nematodes in capybaras may be context dependent. We propose that the context-dependent immune investment documented in capybaras may be the cause of these varying interactions.

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Mosquitoes that feed on crocodilians are poorly known, despite the potential role of these exothermic animals as reservoirs of arboviruses. In this article, we assessed the frequency, abundance, and temporal variation of caiman-biting mosquitoes as well as searched for the natural vectors of the blood parasite of caimans, Hepatozoon caimani, in the Pantanal area of central-western Brazil from captures conducted bimonthly from September 2006 to September 2007 and in February 2008. A total of 5,272 mosquitoes belonging to 10 species of five genera was caught on caimans. The most abundant species were Culex (Melanoconion) theobaldi, Mansonia (Mansonia) titillans, Mansonia (Man.) humeralis, and Mansonia (Man.) amazonensis, which together accounted for 80% of all sampled individuals. Other blood-feeding Melanoconion species were also found quite frequently on caimans, including Culex clarki, Culex idottus, and Culex bastagarius. Oocysts of H. caimani were exclusively detected in Culex species, mainly in individuals of the subgenus Melanoconion, and we accomplished experimental transmission from naturally infected mosquitoes to uninfected Caiman yacare. The highest infection rates were observed in Cx. theobaldi (0.55%), which is therefore indicated as the primary vector of H. caimani. In addition, because the above mentioned Melanoconion and Mansonia species are abundant, widespread, and have a broad set of hosts, including crocodilians, they may be suggested as potential vectors of arboviruses, such as West Nile virus, in the Southern Cone in South America.

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Hammondia heydorni is a cyst forming coccidia closely related to other apicomplexans, such as Toxoplasma gondii, Neospora caninum and Hammondia hammondi with a two-host life cycle. Dogs and other canids as red foxes (Vulpes vulpes) and coyotes (Canis latrans) may serve as definitive hosts for H. heydorni. Sporulated oocysts are infective for cattle, sheep and goats, which may serve as intermediate hosts. Herein, we describe the ability of crab-eating fox (Cerdocyon thous), a wild carnivore that is commonly found from northern Argentina to northern South America, to serve as definitive host of H. heydorni. The whole masseter muscle and brain from two 2-year-old bovines were collected, minced and pooled together for the fox infection. The bovine pooled tissues were equally administered to four foxes, in two consecutive days. Two foxes shed subspherical unsporulated oocysts measuring 10-15microm, after 8 and 9 days post-infection, respectively. One of the foxes eliminated oocysts for 5 days, while the other fox shed oocysts for 9 days. A DNA sample of oocysts detected at each day of oocyst elimination was tested by two PCRs, one of them carried out employing primers directed to the common toxoplasmatiid 18S and 5.8S ribosomal RNA coding genes (PCR-ITS1) and the other based on heat-shock protein 70kDa coding gene (PCR-HSP70). These samples were also submitted to a N. caninum specific nested-PCR protocol based on a N. caninum specific gene (Nc5-nPCR). All of them were positive by PCR-ITS1 and PCR-HSP70 but negative by Nc5-nPCR. The PCR-ITS1 and PCR-HSP70 nucleotide sequences amplified from the oocysts shed by the foxes revealed 100% identity with homologous sequences of H. heydorni. In conclusion, it is clear that H. heydorni also uses the crab-eating fox as a definitive host. The crab-eating fox is usually reported to live in close contact with livestock in several regions of Brazil. Therefore, it is reasonable to infer that such carnivores may play an important role in the sylvatic and domestic cycles of H. heydorni infection.

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Laboratory reared Culex quinquefasciatus Say, 1823 originating from the vicinity of Belem, in northern Brazil, were allowed to engorge on caimans (Caiman c. crocodilus) infected with Hepatozoon caimani (Carini, 1909) and boas (Boa constrictor) infected with H. cf. terzii (Sambon and Seligmann, 1907) both from Para State. Engorged mosquitoes killed on successive days post-feeding (p.f.) were studied by transmission electron microscopy. Images of oocysts from 13 days p.f., caiman-fed mosquitoes were also examined by scanning electron microscopy. The Hepatozoon spp. from the respective hosts differed in their ability to develop in C. quinquefasciatus. Most female mosquitoes fed on caimans, became fully engorged, and survived beyond 22 days p.f., whereas those engorged on boa became debilitated and did not survive beyond 9 days p.f. In boa-fed mosquitoes oocysts were found on the 6th day p.f. The few mosquitoes surviving to the 9th day p.f. contained either undivided oocysts or those that had already commenced sporogenic division. By 8-10 days p.f. caiman-fed mosquitoes contained uninucleate oocysts. Sporogonic divisions were observed from day 12 p.f. onwards. Although sporogenic development conformed in general with the previously reported accounts, the study allowed a more detailed examination of the plasmalemmal endocytotic system, and the consolidation of the crystalline body in specialized 'factories' of cystalline material. Sporozoite differentiation occasionally started on the 18th day p.f., but otherwise was observed only on day 22 p.f.

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