Specialist versus generalist parasites: the interactions between host diversity, environment and geographic barriers in avian malaria.

The specialist versus generalist strategies of hemoparasites in relation to their avian host, as well as environmental factors, can influence their prevalence, diversity and distribution. In this paper we investigated the influence of avian host species, as well as the environmental and geographical factors, on the strategies of Haemoproteus and Plasmodium hemoparasites. We determined prevalence and diversity by targeting their cytochrome b (Cytb) in a total of 2,590 passerine samples from 138 localities of Central and South America, and analysed biogeographic patterns and host-parasite relationships. We found a total prevalence of 23.2%. Haemoproteus presented a higher prevalence (15.3%) than Plasmodium (4.3%), as well as a higher diversity and host specificity. We determined that Plasmodium and Haemoproteus prevalences correlated positively with host diversity (Shannon index) and were significantly influenced by bird diversity, demonstrating a possible "amplification effect". We found an effect of locality and the avian family for prevalences of Haemoproteus and Plasmodium. These results suggest that Haemoproteus is more specialist than Plasmodium and could be mostly influenced by its avian host and the Andes Mountains.

Latitudinal gradients of haemosporidian parasites: Prevalence, diversity and drivers of infection in the Thorn-tailed Rayadito (Aphrastura spinicauda).

Latitudinal gradients are well-suited systems that may be helpful explaining distribution of haemosporidian parasites and host susceptibility. We studied the prevalence, diversity and drivers of haemosporidian parasites (Leucocytozoon, Plasmodium and Haemoproteus) along a latitudinal gradient (30°-56° S), that encompass the total distribution (~3,000 km) of the Thorn-tailed Rayadito (Aphrastura spinicauda) in the South American temperate forests from Chile. We analyzed 516 individuals from 18 localities between 2010 and 2017 and observed an overall prevalence of 28.3% for haemosporidian parasites. Leucocytozoon was the most prevalent parasite (25.8%). We recorded 19 distinct lineages (13 for Leucocytozoon, five for Plasmodium, and one for Haemoproteus). Differences in haemosporidian prevalence and diversity by genus and type of habitat were observed in the latitudinal gradient. Further, we support the existence of a latitudinal associate distribution of Leucocytozoids in South America, where prevalence and diversity increase toward higher latitudes. Distribution of Leucocytozoon was associated with sub-antarctic habitat (higher latitude) and explained by cold temperature and high precipitation. On the other hand, we lacked to find a latitudinal associate pattern for Plasmodium and Haemoproteus, however low prevalence and high diversity were recorded in areas considered as a hotspot of biodiversity in Central Chile. Our findings confirmed the importance of habitat and climatic variables explaining prevalence, diversity and distribution of haemosporidian parasites in a huge latitudinal gradient, belonging the distribution of the Thorn-tailed Rayadito in the world's southernmost forests ecosystems.

Spatial distribution, prevalence and diversity of haemosporidians in the rufous-collared sparrow, Zonotrichia capensis.

BACKGROUND: Parasite prevalence and diversity are determined by the distribution of hosts and vectors and by the interplay among a suite of environmental factors. Distributions of parasite lineages vary based on host susceptibility and geographical barriers. Hemoparasites of the genera Haemoproteus and Plasmodium have wide distributions, and high prevalence and genetic diversity within perching birds (Order Passeriformes). The rufous-collared sparrow (Zonotrichia capensis) is widely distributed in Central and South America across an immense diversity of environments from sea level to more than 4000 meters above sea level. It therefore provides an excellent model to investigate whether altitudinal and latitudinal gradients influence the distribution, prevalence and diversity of haemosporidian parasites, their population structure and the biogeographical boundaries of distinct parasite lineages. RESULTS: We assembled samples from 1317 rufous-collared sparrows spanning 75 locales from across Central and South America (between 9.5°N and 54°S; 10-4655 meters above sea level). We used DNA sequence data from a fragment of the mitochondrial cytochrome b gene (cytb) of Haemoproteus and Plasmodium from 325 positive samples and found prevalences of 22 and 3%, respectively. Haemoproteus exhibited a higher prevalence than Plasmodium but with comparatively lower genetic diversity. We detected a relationship of Plasmodium and Haemoproteus prevalence with altitude and latitude; however, altitude and latitude did not influence parasite diversity. CONCLUSIONS: Parasite lineages showed a phylogeographical boundary coincident with the Andes Mountains, although we also observed a north-south disjunction in Peru for Haemoproteus. Haemosporidian distribution was not homogeneous but differed based on latitude and altitude. This is most probably due to environmental factors that have influenced both vector distribution and abundance, as well as parasite development. Our study provides key insights on the distribution of haemoparasite lineages and parasite dynamics within hosts.

HEMATOLOGIC AND BIOCHEMICAL PARAMETERS OF KELP GULLS (LARUS DOMINICANUS) CAPTURED IN THE CITY OF TALCAHUANO, CHILE.

In order to provide tools for future health-based monitoring programs, we developed reference intervals for hematology and plasma biochemistry and partitioned data for sex and season (winter and autumn). Ninety-one physically healthy kelp gulls (Larus dominicanus) were sampled in the city of Talcahuano, Chile, during winter (July-September) of 2007, autumn (April-June) and winter of 2008, and autumn of 2009. After blood sampling, the kelp gulls were euthanized by cervical dislocation. Packed cell volume (PCV), hemoglobin, total plasma protein (TPP), and complete blood count were performed. Alanine amino transferase, gamma-glutamyl transpeptidase, lactate dehydrogenase, alkaline phosphatase (ALP), creatinine, urea, calcium, phosphorus, and uric acid were analyzed. No significant differences were found between sexes (P>0.05). When a comparison was made between the two seasons, the values of PCV, TPP, white blood cell, heterophils, eosinophils, and monocytes were significantly higher in winter than in autumn (P<0.05) while and urea and uric acid concentrations were higher in autumn. Heterophils were the predominant circulating leukocyte for all birds. There was no significant difference in body condition between autumn and winter nor between sexes. Body condition showed a significant relationship with TPP and basophil concentration and ALP activity.