Haemosporida is a large group of vector-borne intracellular parasites that infect amphibians, reptiles, birds, and mammals. This group includes the different malaria parasites (Plasmodium spp.) that infect humans around the world. Our knowledge on the full life cycle of these parasites is most complete for those parasites that infect humans and, to some extent, birds. However, our current knowledge on haemosporidian life cycles is characterized by a paucity of information concerning the vector species responsible for their transmission among vertebrates. Moreover, our taxonomic and systematic knowledge of haemosporidians is far from complete, in particular because of insufficient sampling in wild vertebrates and in tropical regions. Detailed experimental studies to identify avian haemosporidian vectors are uncommon, with only a few published during the last 25 years. As such, little knowledge has accumulated on haemosporidian life cycles during the last three decades, hindering progress in ecology, evolution, and systematic studies of these avian parasites. Nonetheless, recently developed molecular tools have facilitated advances in haemosporidian research. DNA can now be extracted from vectors' blood meals and the vertebrate host identified; if the blood meal is infected by haemosporidians, the parasite's genetic lineage can also be identified. While this molecular tool should help to identify putative vector species, detailed experimental studies on vector competence are still needed. Furthermore, molecular tools have helped to refine our knowledge on Haemosporida taxonomy and systematics. Herein we review studies conducted on Diptera vectors transmitting avian haemosporidians from the late 1800s to the present. We also review work on Haemosporida taxonomy and systematics since the first application of molecular techniques and provide recommendations and suggest future research directions. Because human encroachment on natural environments brings human populations into contact with novel parasite sources, we stress that the best way to avoid emergent and reemergent diseases is through a program encompassing ecological restoration, environmental education, and enhanced understanding of the value of ecosystem services.

Changing environmental conditions and human encroachment on natural habitats bring human populations closer to novel sources of parasites, which might then develop into new emerging diseases. Diseases transmitted by host generalist vectors are of special interest due to their capacity to move pathogens into novel hosts. We hypothesize that humans using forests for recreation are exposed to a broad range of parasites from wild animals and their vectors. A corollary of this is that new vector-host, parasite-host, and vector-parasite associations could eventually develop. Thus, we expect to observe atypical vector-host associations. Using molecular bloodmeal analysis via amplification of the mtDNA COI gene we identified the vertebrate hosts of Culicoides (Diptera: Ceratopogonidae) species in a sub-urban forest of Southwestern Germany. Bloodmeals were also checked for haemosporidian infections by amplifying a fragment of the mtDNA cyt b gene. We identified a total of 20 Culicoides species, thirteen of which fed on humans. From 105 screened bloodmeals we obtained high quality sequences for 77 samples, 73 (94.8%) originated from humans, two from livestock (Bos taurus and Equus caballus), and two from wild birds (Sylvia atricapilla and Turdus merula). We found that four Culicoides species previously assumed to feed exclusively on either birds (C. kibunensis) or domestic mammals (C. chiopterus, C. deltus, C. scoticus) fed also on humans. A total of six Culicoides abdomens were infected with avian haemosporidian parasites (Plasmodium or Haemoproteus), four of those abdomens contained blood derived from humans. Our results suggest that parasites of wild animals may be transferred to humans through infectious bites of Culicoides vectors. Further, we show that Culicoides vectors believed to be a specialist on specific vertebrate groups can have plastic feeding preferences, and that Culicoides are susceptible to infection by Plasmodium parasites, though vector viability must still be experimentally demonstrated.

Assuming that co-distributed species are exposed to similar environmental conditions, ecological niche models (ENMs) of bird and plant species inhabiting tropical dry forests (TDFs) in Mexico were developed to evaluate future projections of their distribution for the years 2050 and 2070. We used ENM-based predictions and climatic data for two Global Climate Models, considering two Representative Concentration Pathway scenarios (RCP4.5/RCP8.5). We also evaluated the effects of habitat loss and the importance of the Mexican system of protected areas (PAs) on the projected models for a more detailed prediction of TDFs and to identify hot spots that require conservation actions. We identified four major distributional areas: the main one located along the Pacific Coast (from Sonora to Chiapas, including the Cape and Bajío regions, and the Balsas river basin), and three isolated areas: the Yucatán peninsula, central Veracruz, and southern Tamaulipas. When considering the effect of habitat loss, a significant reduction (~61%) of the TDFs predicted area occurred, whereas climate-change models suggested (in comparison with the present distribution model) an increase in area of 3.0-10.0% and 3.0-9.0% for 2050 and 2070, respectively. In future scenarios, TDFs will occupy areas above its current average elevational distribution that are outside of its present geographical range. Our findings show that TDFs may persist in Mexican territory until the middle of the XXI century; however, the challenges about long-term conservation are partially addressed (only 7% unaffected within the Mexican network of PAs) with the current Mexican PAs network. Based on our ENM approach, we suggest that a combination of models of species inhabiting present TDFs and taking into account change scenarios represent an invaluable tool to create new PAs and ecological corridors, as a response to the increasing levels of habitat destruction and the effects of climate change on this ecosystem.