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Sandflies are known vectors of leishmaniasis. In the Old World, sandflies are also vectors of viruses while little is known about the capacity of New World insects to transmit viruses to humans. Here, we relate the identification of RNA sequences with homology to rhabdovirus nucleocapsids (NcPs) genes, initially in the Lutzomyia longipalpis LL5 cell lineage, named NcP1.1 and NcP2. The Rhabdoviridae family never retrotranscribes its RNA genome to DNA. The sequences here described were identified in cDNA and DNA from LL-5 cells and in adult insects indicating that they are transcribed endogenous viral elements (EVEs). The presence of NcP1.1 and NcP2 in the L. longipalpis genome was confirmed in silico. In addition to showing the genomic location of NcP1.1 and NcP2, we identified another rhabdoviral insertion named NcP1.2. Analysis of small RNA molecules derived from these sequences showed that NcP1.1 and NcP1.2 present a profile consistent with elements targeted by primary piRNAs, while NcP2 was restricted to the degradation profile. The presence of NcP1.1 and NcP2 was investigated in sandfly populations from South America and the Old World. These EVEs are shared by different sandfly populations in South America while none of the Old World species studied presented the insertions.

Strategies for the prevention and control of commensal rodents would improve with better knowledge of their response to environmental factors from different spatial scales. In this research we evaluated which different scales environmental characteristics determine rodent infestation levels in a subtropical urban to rural landscape gradient in Misiones, Argentina. A total of 87 households from an urban, a periurban and a rural landscape were surveyed at least once, with nine households surveyed repeatedly along five consecutive seasons. Rodent infestation levels were estimated using nontoxic bait stations set up in the backyard and garden of each household. Different environmental characteristics at several spatial scales were obtained from field surveys and land cover classification based on a satellite image. Rattus spp. was detected in 42.5% of the households. The lowest rodent infestations occurred in winter. Infestation levels showed spatial dependence up to 2500 m. Rodent infestation was associated with landscape types and environmental characteristics at the macro and microhabitat scales. Macrohabitat characteristics explained 53.7% of the variation of rodent infestation levels, whereas microscale explained 28.0% and landscape type only 2%. This multiscale study provides evidence that households’ characteristics may not be the most important factor to explain variations in the abundance of commensal rodents’ around human dwellings. As a consequence, prevention and control measures would be more effective if applied at the neighborhood level and during winter, since it is a critical time for preventing compensatory population responses in rodent infestations.

Abstract Yellow fever (YF) epizootics in South America during the 21st century have an unprecedented recorded magnitude and geographical dispersion. The YF spread progressively involved areas considered previously free of risk reaching the edge of cities with large unvaccinated populations, and urban outbreaks were frequently forecasted. We critically reviewed the initial stages and enhancing contexts of YF urban epidemics since the 17th century in the Americas, and the modeling attempts of YF epidemic risk by of Aedes-Human transmission, to find common factors that increase the probability of these events in the current scenarios. The YF urban outbreaks of the past showed as necessary conditions the multiple introduction by viremic carriers clustered in time and space, coincident with population peaks of Aedes. These conditions are not met in the current outbreaks in the Americas by sylvatic YF cycles, besides the protective impact of vector control campaigns, vaccination coverage, improved surveillance, and case management. Therefore, urban Aedes-Human YF outbreaks in the Americas are still possible but with low probability or very focal transmission, while the conditions reported in the past were avoided, and the surveillance and control measures sustained, including the vaccination of the population at risk.