Effects of Artificial Flooding for Hydroelectric Development on the Population of Mansonia humeralis (Diptera: Culicidae) in the Paraná River, São Paulo, Brazil

The closure of two phases of the dam at the Porto Primavera Hydroelectric Plant on the Paraná River flooded a flawed system located in the Municipality of Presidente Epitácio, São Paulo state, favoring the proliferation of aquatic weeds. This study aimed to observe the population of Mansonia humeralis in the area, monitoring the richness, diversity, and dominance of this species both before and during different phases of reservoir flooding as well as evaluate its possible consequences concerning human and animal contact. Adult mosquitoes were collected monthly in the following periods: at the original level, after the first flood, and after the maximum level had been reached between 1997 and 2002. Collection methods used were an aspirator, a Shannon trap, and the Human Attractive Technique. A total of 30,723 mosquitoes were collected, Ma. humeralis accounting for 3.1% in the preflood phase, 59.6% in the intermediate, and 53.8% at maximum level. This species is relevant to public health, since the prospect of continued contact between Ma. humeralis and the human population enhances the dam's importance in the production of nuisance mosquitoes, possibly facilitating the transmission of arboviruses. Local authorities should continue to monitor culicid activity through sustainable entomological surveillance

Riqueza e abundância de Culicidae (Diptera) em área impactada, Mato Grosso do Sul, Brasil

The damming of Paraná River for the construction of Porto Primavera Hydroelectric Power Plant, between the states of Mato Grosso do Sul, Midwestern Brazil and São Paulo, Southeastern Brazil, has changed the ecological relationships in the area. The objective of the study was to describe the fauna that can be potential vectors in this reservoir, 2 km away from its right bank, in Bataguassu, Mato Grosso do Sul, before flooding. Mosquitoes were monthly captured in different environments from July 1997 to November 1999. During this period 16,553 adult specimens and 1,795 immature forms were collected with richness of 86 different species of adults and 44 different species of immature forms. The fauna presented a richness that included species of epidemiological importance, as Anopheles darlingi and other mosquitoes with potential for arbovirus transmission.O represamento do Rio Pananá para construção da hidrelétrica de Porto Primavera, entre os Estados do Mato Grosso do Sul e São Paulo, alterou as relações ecológicas na região. O objetivo do estudo foi descrever a fauna de culicídeos potencialmente vetores nesse reservatório, a 2km da margem direita, em Bataguassu, Mato Grosso do Sul, na fase anterior à inundação. Os culicídeos foram capturados em ambientes distintos mensalmente, de julho de 1997 a novembro de 1999. Foram calculados índices de riqueza e abundância. Obtiveram-se 16.553 exemplares adultos e 1.795 imaturos, com riqueza de 86 e 44 espécies, respectivamente. A fauna culicídea da área de estudo apresentava relativa riqueza, com espécies de valor epidemiológico, como o Anopheles darlingi, além de outras com potencial na veiculação de arbovírus

Evaluation of Methods to Collect Diurnal Culicidae (Diptera) at Canopy and Ground Strata, in the Atlantic Forest Biome

Hand-held insect nets are the standard method for capturing vector mosquitoes of sylvatic arboviruses; however, occupational risks and biases due to individual skill and attractiveness are important limitations. The use of chemical attractants and automatic traps could be an alternative to resolve these limitations. This study compares the yields achieved using nets with those employing electrical traps with CO2 and BG-Lure®, near the ground and in the canopy strata (6.0 and 8.0 m high). The study was conducted at the Cantareira State Park, which is in the Brazilian Atlantic Forest biome. In the 18 collections performed, 3570 specimens of 52 taxa were obtained. The most frequent species captured near the ground were Wyeomyia confusa and Limatus durhamii, whereas Sabethes albiprivus, Sabethes purpureus, and Haemagogus leucocelaenus were the most frequent in the canopy. The nets resulted in greater species richness and abundance, followed by the trap employing CO2. The combination of CO2 traps with BG-Lure® did not improve performance. The use of BG-Lure® alone resulted in low abundance and a low number of species. Our results demonstrate that the use of traps with CO2 can be complementary to collections with nets; however, for species of epidemiological interest such as those of the genera Haemagogus and Sabethes, especially in the canopy, the net remains the method of choice

Roads and forest edges facilitate yellow fever virus dispersion

Landscape connectivity is important for a wide range of ecological processes, including to disease spread, once it describes the degree to which landscapes facilitate or impede vector and hosts dispersion. Understanding connectivity is extremely important to identify where pathogens can move, and at what speed, allowing the organization of vaccination campaigns or other preventive measures. To better understand the effects of landscape connectivity on yellow fever virus (YFV) dispersion in Brazil, we used a network approach and modelled the movement of non-human primates' cases, the so-called epizootic events, over time. The networks consider each epizootic event as a node and the dispersion between nodes as links. Those links were established considering, respectively, the date of each epizootic event, the distance among the nodes and the permeability of the landscape between each pair of nodes. Our results demonstrated that on average YFV dispersed 1.42 km/day, with the largest movement being 6.9 km/day. Dispersions were longer in summer (1.2 km/day) than in winter (0.22 km/day). Most dispersal movements occurred up to 1 km/day (71%) and within a week after the arrival of the virus in the source node (73%), except in winter, where dispersions occurred within a period of up to 20 days. The best model indicates that YFV disperses mainly through roads adjacent to forest areas, and along forest edges (within a range of 100 m) in interface with agricultural areas, water and forestry areas. Core areas of urban, agricultural and forest regions were important barriers for virus movement. Synthesis and applications. Through landscape connectivity analyses, we provided here the first evidence that highly fragmented landscapes with a wide road network and large densities of forest edges facilitate yellow fever virus propagation, and that the maintenance of large blocks of forest can help to inhibit this spread. These results can contribute to guide forest restoration and landscape management actions in order to amplify health benefits related to restoration projects, in addition to their benefits for biodiversity conservation and climate change mitigation.</p

Climate and land-use shape the spread of zoonotic yellow fever virus

attente version publiée pour compléter informationsZoonotic viruses that originate in wildlife harm global human health and economic prosperity 1 . Understanding virus transmission at the human-animal-environment interface is a key component of pandemic risk-reduction 2,3 . Zoonotic disease emergence is highest in biodiverse, tropical forests undergoing intensive land-use change 4,5 . Phylodynamic analyses of virus genomes can powerfully test epidemiological hypotheses, but are rarely applied to viruses of animals inhabiting these habitats. Brazil’s densely-populated Atlantic Forest and Cerrado region experienced in 2016–2021 an explosive human outbreak of sylvatic yellow fever, caused by repeated virus spillover from wild neotropical primates 6 . Here we use yellow fever virus (YFV) genome sequences and epidemiological data from neotropical primates, humans, and mosquito vectors to identify the environmental, demographic, and climatic factors determining zoonotic virus spread. Using portable sequencing approaches we generated 498 YFV genomes, resulting in a well-sampled dataset of zoonotic virus genomes sampled from wild mammals. YFV dispersal velocity was slower at higher elevation, in colder regions, and further away from main roads. Virus lineage dispersal was more frequent through wetter areas, areas with high neotropical primate density and through landscapes covered by mosaic vegetation. Higher temperatures were associated with higher virus effective population sizes, and peaks of transmission in warmer, wetter seasons were associated with higher virus evolutionary rates. Our study demonstrates how zoonotic disease transmission is linked to land-use and climate, underscoring the need for One-Health approaches to reducing the rate of zoonotic spillover