Dirofilaria immitis is endemic in rural areas of the Brazilian Amazonas state capital, Manaus.

The canine filarial parasite Dirofilaria immitis has not been reported in Brazil´s Amazonas state capital, Manaus, for over a century. Here, we report one imported and 27 autochthonous D. immitis infections from a microfilarial survey of 766 domestic dog blood samples collected between 2017 and 2021 in Manaus. An Overall prevalence estimate of 15.44% (23/149) was calculated from our two rural collection sites; a prevalence of 1.22% (4/328) was estimated at our periurban collection site, and an overall prevalence of 0.35% (1/289) was calculated from our two urban clinic collections. Our data suggest that in the urban areas of Manaus, where the parasites are very likely vectored by the same species of mosquito that historically vectored Wuchereria bancrofti (Culex quinquefasciatus), prevalence levels are very low and possibly maintained by an influx from rural areas where sylvatic reservoirs and/or more favorable vector transmission dynamics maintain high prevalences.

Diversity of biting midges Culicoides (Diptera: Ceratopogonidae), potential vectors of disease, in different environments in an Amazonian rural settlement, Brazil.

INTRODUCTION: The Culicoides transmit a variety of pathogens. Our aim was to survey the Culicoides species occurring in an Amazonian rural settlement, comparing abundance, richness, and diversity in different environments. METHODS: Culicoides were captured using CDC light traps. The Shannon-Wiener (H') and Rényi indices were used to compare species diversity and evenness between environments, the equitability (J') index was used to calculate the uniformity of distribution among species, and similarity was estimated using the Jaccard similarity index. A permutational multivariate analysis of variance was applied to assess the influence of environment on species composition. A non-metric dimensional scale was used to represent the diversity profiles of each environment in a multidimensional space. RESULTS: 6.078 Culicoides were captured, representing 84 species (45 valid species/39 morphotypes). H' values showed the following gradient: forest > capoeira > peridomicile > forest edge. The equitability J' was greater in capoeira and forests compared to peridomiciles and the forest edge. The population compositions of each environment differed statistically, but rarefaction estimates indicate that environments of the same type possessed similar levels of richness. Species of medical and veterinary importance were found primarily in peridomiciles: C. paraensis, vector of Oropouche virus; C. insignis and C. pusillus, vectors of Bluetongue virus; C. filariferus, C. flavivenula, C. foxi, and C. ignacioi, found carrying Leishmania DNA. CONCLUSIONS: This study indicates that diversity was higher in natural environments than in anthropized environments, while abundance and richness were highest in the most anthropized environment. These findings suggest that strictly wild Culicoides can adapt to anthropized environments.

Diversity of biting midges Culicoides (Diptera: Ceratopogonidae), potential vectors of disease, in different environments in an Amazonian rural settlement, Brazil

Abstract INTRODUCTION: The Culicoides transmit a variety of pathogens. Our aim was to survey the Culicoides species occurring in an Amazonian rural settlement, comparing abundance, richness, and diversity in different environments. METHODS: Culicoides were captured using CDC light traps. The Shannon-Wiener (H') and Rényi indices were used to compare species diversity and evenness between environments, the equitability (J') index was used to calculate the uniformity of distribution among species, and similarity was estimated using the Jaccard similarity index. A permutational multivariate analysis of variance was applied to assess the influence of environment on species composition. A non-metric dimensional scale was used to represent the diversity profiles of each environment in a multidimensional space. RESULTS: 6.078 Culicoides were captured, representing 84 species (45 valid species/39 morphotypes). H' values showed the following gradient: forest > capoeira > peridomicile > forest edge. The equitability J' was greater in capoeira and forests compared to peridomiciles and the forest edge. The population compositions of each environment differed statistically, but rarefaction estimates indicate that environments of the same type possessed similar levels of richness. Species of medical and veterinary importance were found primarily in peridomiciles: C. paraensis, vector of Oropouche virus; C. insignis and C. pusillus, vectors of Bluetongue virus; C. filariferus, C. flavivenula, C. foxi, and C. ignacioi, found carrying Leishmania DNA. CONCLUSIONS: This study indicates that diversity was higher in natural environments than in anthropized environments, while abundance and richness were highest in the most anthropized environment. These findings suggest that strictly wild Culicoides can adapt to anthropized environments.

New species records of Culicoides biting midges (Diptera: Ceratopogonidae) for the state of Rondônia in Brazilian Amazon.

BACKGROUND: Culicoides biting midges are small insects that are proven vectors of pathogens that cause disease in animals and humans. There are 1,368 species of Culicoides in the world, including 149 species in Brazil and 122 species in the Brazilian Amazon Basin. This study documents specimens that were collected between 2013 and 2015 in the municipalities of Alvorada d'Oeste, Buritis, Cacoal, Costa Marques, Espigão d'Oeste, Guajará-Mirim, Pimenta Bueno, Porto Velho and São Francisco Guaporé. Collections were performed using HP light traps in forest, pasture and peridomicilie environments. NEW INFORMATION: Species newly recorded in Rondônia State include Culicoides carpenteri Wirth & Blanton, 1953; C. dasyophrus Macfie, 1940; C. eublepharus Macfie, 1948; C. galindoi Wirth & Blanton, 1953; C. heliconiae Fox & Hoffman, 1944; and C. ignacioi Forattini, 1957. This is the first record in Brazil of C. darlingtonae Wirth & Blanton, 1971.

Culicoides hildebrandoi, a new species of the reticulatus species group from the Brazilian Amazon Region (Diptera, Ceratopogonidae).

A new species of biting midge (Diptera: Ceratopogonidae), Culicoides hildebrandoi sp. n., is described and illustrated based on female and male specimens from the states of Amazonas and Rondônia, Brazil. This new species belongs to the reticulatus species group and differs from the 24 other species of this group by the elongate slightly swollen 3(rd) palpal segment with scattered capitate sensilla but lacking a sensory pit.

The genital atrium armature of some Brazilian sand fly females (Diptera: Phlebotominae) / Armadura do átrio genital de algumas fêmeas de flebotomíneos brasileiros (Diptera: Phlebotominae)

Phlebotomine sand flies are insects of medical importance. Species in the Neotropical region are highly diverse. Some of these species are considered cryptic species because of their morphological similarity between adult females of different species make identification especially difficult. The aim of this study was to analyze and describe the armature in the genital atrium (AGA) of some adult female sand flies, in order to discover new taxonomic characters that make it possible to distinguish between species that would otherwise be treated as cryptic by analysis of the AGA. The AGA of 16 Phlebotomine sand fly species are described. Distinct differences were found in relation to the shape and size of the armature, the presence or absence of spines on the armature, and the shape, size, and grouping patterns of the spines. These characters made it possible to distinguish between the species studied.

Os flebotomíneos são insetos de importância médica. Na região Neotropical existe grande diversidade de espécies. Algumas dessas espécies são consideradas espécies crípticas devido às semelhanças morfológicas entre fêmeas adultas de diferentes espécies, tornando a identificação especialmente difícil. O objetivo deste estudo foi analisar e descrever a armadura no átrio genital (AAG) de algumas fêmeas adultas de flebotomíneos, a fim de descobrir novos caracteres taxonômicos que tornem possível a distinção por análise da AAG entre as espécies que poderiam ser tratadas como espécies crípticas. Foram descritas a AAG de 16 espécies de flebotomíneos. Diferenças distintas foram encontradas em relação à forma e ao tamanho da armadura, a presença ou ausência de espinhos na armadura, e a forma, tamanho e padrões de agrupamento dos espinhos. Esses caracteres tornou possível a distinção entre as espécies estudadas.