Testing hypotheses on drivers of clade evolution and trait diversification provides insight into many aspects of evolutionary biology. Often, studies investigate only intrinsic biological properties of organisms as the causes of diversity, however, extrinsic properties of a clade's environment, particularly geological history, may also offer compelling explanations. The Andes are a young mountain chain known to have shaped many aspects of climate and diversity of South America. The Liolaemidae are a radiation of South American reptiles with over 300 species found across most biomes and with similar numbers of egg‐laying and live‐bearing species. Using the most complete dated phylogeny of the family, we tested the role of Andean uplift in biogeography, diversification patterns, and parity mode of the Liolaemidae. We find that the Andes promoted lineage diversification and acted as a species pump into surrounding biomes. We also find strong support for the role of Andean uplift in boosting the species diversity of these lizards via allopatric fragmentation. Finally, we find repeated shifts in parity mode associated with changing thermal niches, with live‐bearing favored in cold climates and egg‐laying favored in warm climates. Importantly, we find evidence for possible reversals to oviparity, an evolutionary transition believed to be extremely rare.

The continued emergence and re-emergence of pathogens represent an ongoing, sometimes major, threat to populations. Hantaviruses (family Bunyaviridae) and their associated human diseases were considered to be confined to Eurasia, but the occurrence of an outbreak in 1993–94 in the southwestern United States led to a great increase in their study among virologists worldwide. Well over 40 hantaviral genotypes have been described, the large majority since 1993, and nearly half of them pathogenic for humans. Hantaviruses cause persistent infections in their reservoir hosts, and in the Americas, human disease is manifest as a cardiopulmonary compromise, hantavirus cardiopulmonary syndrome (HCPS), with case-fatality ratios, for the most common viral serotypes, between 30% and 40%. Habitat disturbance and larger-scale ecological disturbances, perhaps including climate change, are among the factors that may have increased the human caseload of HCPS between 1993 and the present. We consider here the features that influence the structure of host population dynamics that may lead to viral outbreaks, as well as the macromolecular determinants of hantaviruses that have been regarded as having potential contribution to pathogenicity.

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Powassan virus (POW) is a tick-borne flavivirus distributed in Canada, the northern USA and the Primorsky region of Russia. POW is the only tick-borne flavivirus endemic to the western hemisphere, where it is transmitted mainly between Ixodes cookei and groundhogs (Marmota monax). Deer tick virus (DTV), a genotype of POW that has been frequently isolated from deer ticks (Ixodes scapularis), appears to be maintained in an enzootic cycle between these ticks and white-footed mice (Peromyscus leucopus). DTV has been isolated from ticks in several regions of North America, including the upper Midwest and the eastern seaboard. The incidence of human disease due to POW is apparently increasing. Previous analysis of tick-borne flaviviruses endemic to North America have been limited to relatively short genome fragments. We therefore assessed the evolutionary dynamics of POW using newly generated complete and partial genome sequences. Maximum-likelihood and Bayesian phylogenetic inferences showed two well-supported, reciprocally monophyletic lineages corresponding to POW and DTV. Bayesian skyline plots based on year-of-sampling data indicated no significant population size change for either virus lineage. Statistical model-based selection analyses showed evidence of purifying selection in both lineages. Positive selection was detected in NS-5 sequences for both lineages and envelope sequences for POW. Our findings confirm that POW and DTV sequences are relatively stable over time, which suggests strong evolutionary constraint, and support field observations that suggest that tick-borne flavivirus populations are extremely stable in enzootic foci.

Deer mice are the principal reservoir hosts of Sin Nombre virus, the etiologic agent of most hantavirus cardiopulmonary syndrome cases in North America. Infection of deer mice results in persistence without conspicuous pathology, and most, if not all, infected mice remain infected for life, with periods of viral shedding. The kinetics of viral load, histopathology, virus distribution, and immune gene expression in deer mice were examined. Viral antigen was detected as early as 5 days postinfection and peaked on day 15 in the lungs, hearts, kidneys, and livers. Viral RNA levels varied substantially but peaked on day 15 in the lungs and heart, and antinucleocapsid IgG antibodies appeared in some animals on day 10, but a strong neutralizing antibody response failed to develop during the 20-day experiment. No clinical signs of disease were observed in any of the infected deer mice. Most genes were repressed on day 2, suggesting a typical early downregulation of gene expression often observed in viral infections. Several chemokine and cytokine genes were elevated, and markers of a T cell response occurred but then declined days later. Splenic transforming growth factor beta (TGF-β) expression was elevated early in infection, declined, and then was elevated again late in infection. Together, these data suggest that a subtle immune response that fails to clear the virus occurs in deer mice.

Andes virus (ANDV) is the predominant etiologic agent of hantavirus cardiopulmonary syndrome (HCPS)in southern South America. In Chile, serologically confirmed human hantavirus infections have occurred throughout a wide latitudinal distribution extending from the regions of Valparaíso (32 to 33°S) to Aysén (46°S) in southern Patagonia. In this study, we found seropositive rodents further north in the Coquimbo region (30°S) in Chile. Rodent seroprevalence was 1.4%, with Oligoryzomys longicaudatus displaying the highest seroprevalence (5.9%), followed by Abrothrix longipilis (1.9%) and other species exhibiting <0.6% seropositivity. We sequenced partial ANDV small (

Cases of human hantavirus disease have been reported in Chile since 1995, most of them in people living in rural and periurban areas. We conducted a peridomestic study of small mammals to evaluate the relationships between the presence of rodents with antibodies to Andes virus confirmed human cases of hantavirus pulmonary syndrome in southcentral Chile. The results of 20 sampled sites, which involved the capture of 272 mice over an 18-month period, showed the occurrence of 10 small mammal species, of which Oligoryzomys longicaudatus was the only seropositive species for hantavirus, with an intra-specific serologic rate of 10.4%.

Chagas disease, caused by the protozoan Trypanosoma cruzi and transmitted by triatomine insect vectors, affects about 10 million people worldwide (Schmunis 2000) and is the third most important global parasitic disease after malaria and schistosomiasis (World Bank 1993). Because of effective vector control campaigns, the number of acute cases has decreased markedly and has been reduced to nearly zero in previously highly endemic areas of Uruguay, Chile and Brazil (Schofield et al. 2006).The Chagas disease vector Triatoma infestans (Klug 1834) was historically considered an e�clusively do-) was historically considered an e�clusively domestic insect, but it has now been reported in sylvan environments (Noireau et al. 2005, Noireau 2009). The first sylvatic population of T. infestans was reported in Cochabamba, Bolivia, inhabiting rock piles associated with wild guinea pigs (Torrico 1946). Other reports have shown T. infestans in Argentina (Mazza & Schreiber 1938, Mazza 1943, Ceballos et al. 2009), Paraguay (Velasquez & González 1959 and Brazil (Barretto et al. 1963) under rocks or trunks of fallen trees, in hollow trees, under bark, in shelters or burrows of marsupials and rodents and in bird nests occupied by owls, parrots or small rodents (Noireau et al. 1997). Wild T. infestans has been found in an e�tended geographical region throughout Chaco and three Andean departments of Bolivia: Cochabamba, La Paz and Potosí (Noireau et al. 1999, Cortez et al. 2007. T. infestans was considered to be eradicable due to its strictly domestic behavior and its non-autochthonous status outside of its apparent centre of origin in the Andean valleys of Bolivia. This theory has been challenged by empirical evidence of wild individuals collected by vector control programs and researchers over several decades (Gürtler 2009). Sylvatic triatomines may occasionally invade human residences, acting as founders of new colonies (Fitzpatrick et al. 2008). Hence, it is necessary to study the ecology and behavior of their populations to understand the domiciliation process and generate new strategies for their control (Beard et al. 2002, Guhl et al. 2009, Moncayo & Silveira 2009).In Chile, parasite transmission from vectors to humans occurs mainly in rural and suburban areas encompassing the northern desert and semiarid and Mediterranean environments, between latitudes 18°30'S and 34°36'S. The triatomine insects T. infestans, Mepraia spinolai (Porter 1934) and Mepraia gajardoi are the vector species that have been reported in that area (Spinola 1852, Neghme 1982, Lent et al. 1994, Frias et al. 1998.In 1991, several countries of South America, including Chile, established the Southern Cone Initiative for control of Chagas disease (INCOSUR-Chagas), which provided united strategy, control actions and an information system used to evaluate local control programs (Silveira 2002). The specific aims of the initiative were the following: (i) the elimination of T. infestans from dwellings and their surroundings in endemic areas, (ii) the reduction an...