The sand fly (Diptera: Psychodidae) fauna of the urban area of Lassance, Northeast Minas Gerais, Brazil

Ecology and molecular analysis of sand flies in Bambuí, Minas Gerais, Brazil: Implications for leishmaniasis surveillance

INTRODUCTION

Leishmaniasis stands out as a public health problem in the state of Minas Gerais, Brazil, especially in the Midwest region. However, the entomological aspects in several municipalities remain unknown. Therefore, this study aimed to investigate the sand fly fauna in Bambuí, encompassing ecological dynamics and molecular detection of Leishmania.

METHODS

Monthly collections were conducted using CDC light traps from September 2018 to August 2020 across 16 selected points with urban and rural characteristics, chosen based on the coverage area of the Municipal Health Department and the occurrence of canine and human visceral leishmaniasis (VL) cases. Ecological indices of the sand fly population (Chao1, Shannon, Simpson and Pielou) were assessed, and sand fly abundance was correlated to climatic variables (humidity, temperature and rainfall).

RESULTS

A total of 8838 specimens representing 17 species within nine genera were collected (estimated species richness by Chao 1 estimator = 17; SE ± 1.8). Predominantly, Lutzomyia longipalpis, Nyssomyia whitmani and Evandromyia cortelezzii constituted approximately 98% of all captured sand flies. While species richness and diversity displayed variations throughout the study, a positive correlation emerged between temperature (p < 0.0001; r = 0.7767), monthly rainfall (p < 0.0001; r = 0.7810) and sand fly abundance. Molecular analysis revealed Leishmania DNA in 2.05% of female sand flies, with the presence of Leishmania infantum in Lu. longipalpis and both Le. infantum and Leishmania braziliensis in Ev. cortelezzii.

CONCLUSIONS

The entomological data, coupled with the occurrence of autochthonous cases of canine visceral leishmaniasis, offer valuable insights for evidence-based strategies to prevent leishmaniasis in Bambuí.

Spatiotemporal changes in exposition risk to leishmaniases vector in residences within a fishing tourism area of Pantanal wetland

Miranda Municipality of Mato Grosso do Sul, borders the Pantanal wetland, a famous fishing destination visited by tourists from all over the world, and is a location where visceral leishmaniasis has been reported. To assess the risk of Leishmania infantum transmission, we studied the sandfly community, focusing on known vector and parasite presence. We conducted light trap collections twice per month at nine sites within the city (including two forested areas) for one year. We collected a total of 12,727 sand flies, 10,891 males and 1,836 females belonging to 11 species: Brumptomyia avellari, Evandromyia aldafalcaoae, Ev. evandroi, Ev. lenti, Ev. sallesi, Ev. walkeri, Lu. longipalpis, Nyssomyia whitmani, Psathyromyia bigeniculata, Pa. hermanlenti and Pa. punctigeniculata. Lutzomyia longipalpis, the proven vector of Leishmania infantum, was captured each month, and was the most abundant species observed, accounting for more than 99% of sand flies captured in most sites, especially where chicken coops were present. Evidence of Leishmania infantum infection was detected in 0.40% of Lu. longipalpis tested. We developed a generalized mixed multilevel model for Lu. longipalpis, that includes within-year seasonality, location of capture (indoors vs. outdoors), vector abundance, and sex ratio. The VL vector was abundant both inside and outside houses. Large numbers of Lu. longipalpis were observed in outdoor sites where domestic animals were present but were absent from forest sites. Our findings suggest high vector populations and Le. infantum presence in a city where tourists could be exposed to visceral leishmaniasis, with significant implications for more surveillance and control activities.

Increased Risk of American Tegumentary Leishmaniasis in an Urban and Rural Area of Caratinga, Brazil between 2016 and 2021

We used spatial analysis tools to examine the epidemiological situation and spatial distribution of American tegumentary leishmaniasis in the municipality of Caratinga between 2016 and 2021. In addition, potential sandfly vectors were captured. All information used in this study was retrieved from public health archives and confirmed in the state health services databases. All cases were analyzed using Geographic Information Systems software. In addition, sandfly collections and molecular detection of Leishmania were carried out in areas with the highest number of cases. During the analyzed period, American tegumentary leishmaniasis (ATL) cases increased and remained high in the last years. The hotspots included urban areas of Caratinga city and the districts of Patrocínio of Caratinga and Sapucaia. The species Nyssomyia whitmani, Nyssomyia intermedia, and Migonemyia migonei were the most abundant species and the ITS1-polymerase chain reaction technique detected Leishmania DNA in these species. On the basis of our analyses, the urbanization of ATL in Caratinga has taken place in recent years. Because of the increase in the number of human cases and the presence of vectors, it is recommended that health authorities focus on control measures in hotspots.

Ecology and natural infection of phlebotomine sand flies in different ecotopes and environments in the municipality of Pains, Minas Gerais, Brazil

Phlebotomines (Diptera: Psychodidae) are vectors of protozoa of the genus Leishmania and distributed throughout Brazil, formerly restricted to rural areas, have expanded including to periurban and urban regions, been recorded in different habitats. This study aimed to understand the dynamics of sand flies in different ecotopes in the municipality of Pains. Sand flies were captured during thirty samplings using HP light traps installed in seven different ecotopes for two consecutive nights, once a month, from August 2018 to July 2019. A total of 1,352 sand flies were captured, representing 24 species belong to ten genera. Evandromyia edwardsi was the most abundant species, followed by Evandromyia lenti and Micropygomyia quinquefer. Leishmania DNA was detected in seven female sand flies in four ecotopes, for an infection rate of 0.9%. Sand flies were collected in all seven ecotopes, although forest (23.04%), cave (20.88%) and pasture (17.75%) had higher abundance and richness. Similarity was found among ecotopes, indicating that they are all important for the maintenance of the sand fly community. Spatial analysis indicated high densities of sand flies in areas with natural characteristics. All ecotopes in the municipality were evidenced to have an adequate and harmonious epidemiological profile for the transmission and expansion of leishmaniasis throughout the territory. Because of the increasing environmental changes and deforestation in the municipality, the risk of generating ecological imbalance and increased cases of leishmaniasis is imminent, which highlights the importance of developing preventive and control strategies.

Leishmania spp. in indigenous populations: A mini-review

Leishmaniasis, considered a neglected vector-borne disease complex of global concern, has a significant impact on indigenous communities due to daily human and animal exposure in periurban, rural, and naturally preserved areas. This mini-review aims to assess and discuss studies of leishmaniasis in these communities of the New World and Old World, particularly those in the Americas and Asia. Such indigenous communities have been mostly built in poor traditional households with no mosquito-net protection, mostly located in environmentally protected areas, favoring vectors and reservoirs. The presence of leishmaniasis cases surrounding such indigenous areas indicated a high risk of infection, which may have been historically underestimated due to a lack of surveillance, even at present. The absence of studies of indigenous populations in recognized endemic areas may reflect insufficient health services. In conclusion, the persistence of this neglectful scenario may impact tragic outcomes and potential outbreaks in indigenous peoples and surroundings populations worldwide.