27 research outputs found
Identification of some Amazonian species of Culex (Culex) and Culex (Melanoconion) by morphotyping and barcoding
Os mosquitos Culex spp. apresentam caracterĂsticas idiossincráticas e sua baixa variabilidade dificulta sua identificação. O objetivo do nosso estudo foi analisar a regiĂŁo 5 'do gene da subunidade I do citocromo oxidase (coI) para a identificação taxonĂ´mica de espĂ©cies de Culex que foram previamente diagnosticadas em subgĂŞneros Culex e Melanoconion em condições de campo. Dez sequĂŞncias de espĂ©cimes foram analisadas pelo Automatic Barcode Gap Discovery (ABGD). Todas as sequĂŞncias apresentaram 94-99% de identidade quando comparadas com outras sequĂŞncias de espĂ©cies de Culex disponĂveis no GenBank. Cinco partições iniciais suportaram 80-88 grupos de espĂ©cies. Entre eles, oito conjuntos continham os espĂ©cimes do presente estudo. Das 10 sequĂŞncias de mosquitos, cinco nĂŁo formaram nenhum cluster consistente, e as demais apresentaram alguma consistĂŞncia no diagnĂłstico taxonĂ´mico nas condições de campo. Nossos resultados sugerem que algumas sequĂŞncias do gene coI de espĂ©cimes podem pertencer a espĂ©cies do subgĂŞnero Melanoconion, cuja sequĂŞncia 5' coI Ă© desconhecida ou inĂ©dita no GenBank.Culex spp. mosquitoes have idiosyncratic characteristics and its low variability makes difficult their identification. The aim of our study was to analyze the 5' region of the cytochrome oxidase subunit I gene (coI) for the taxonomic identification of Culex species which were previously morphotyped and diagnosed in Culex and Melanoconion subgenera at the field conditions. Ten specimen sequences were analyzed by the Automatic Barcode Gap Discovery (ABGD). All sequences showed 94-99% identity when compared to other Culex species sequences available from GenBank. Five initial partitions supported 80-88 species groups. Among them, eight sets contained the specimens of the present study. Of the 10 mosquito sequences, five did not form any consistent cluster, and the remaining showed some consistency in the taxonomic diagnosis at the field conditions. Our results suggest that some coI gene sequences of specimens may belong to species of the subgenus Melanoconion, whose 5’ coI sequence is unknown or unpublished in GenBank
Successful isolation of Leishmania infantum from Rhipicephalus sanguineus sensu lato (Acari : Ixodidae) collected from naturally infected dogs
Background: The main transmission route of Leishmania infantum is through the bites of sand flies. However, alternative mechanisms are being investigated, such as through the bites of ticks, which could have epidemiological relevance. The objective of this work was to verify the presence of Leishmania spp. In Rhipicephalus sanguineus sensu lato collected from naturally infected dogs in the Federal District of Brazil. Methods: Ticks were dissected to remove their intestines and salivary glands for DNA extraction and the subsequent amplification of the conserved region of 120 bp of kDNA and 234 bp of the hsp70 gene of Leishmania spp. The amplified kDNA products were digested with endonucleases HaeIII and BstUI and were submitted to DNA sequencing. Isolated Leishmania parasites from these ticks were analyzed by multilocus enzyme electrophoresis, and the DNA obtained from this culture was subjected to microsatellite analyses. Results: Overall, 130 specimens of R. sanguineus were collected from 27 dogs. Leishmania spp. were successfully isolated in culture from five pools of salivary glands and the intestines of ticks collected from four dogs. The amplified kDNA products from the dog blood samples and from the tick cultures, when digested by HaeIII and BstUI, revealed the presence of L. braziliensis and L. infantum. One strain was cultivated and characterized as L. infantum by enzyme electrophoresis. The amplified kDNA products from the blood of one dog showed a sequence homology with L. braziliensis; however, the amplified kDNA from the ticks collected from this dog showed a sequence homology to L. infantum. Conclusion: The results confirm that the specimens of R. sanguineus that feed on dogs naturally infected by L. infantum contain the parasite DNA in their intestines and salivary glands, and viable L. infantum can be successfully isolated from these ectoparasites
Breeding sites of Aedes aegypti in metropolitan vacant lots in Greater VitĂłria, State of EspĂrito Santo, Brazil
Successful isolation of Leishmania infantum from Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) collected from naturally infected dogs
The Genetic Structure of Leishmania infantum Populations in Brazil and Its Possible Association with the Transmission Cycle of Visceral Leishmaniasis
Leishmania infantum is the etiologic agent of visceral leishmaniasis (VL) in the Americas, Mediterranean basin and West and Central Asia. Although the geographic structure of L. infantum populations from the Old World have been described, few studies have addressed the population structure of this parasite in the Neotropical region. We employed 14 microsatellites to analyze the population structure of the L. infantum strains isolated from humans and dogs from most of the Brazilian states endemic for VL and from Paraguay. The results indicate a low genetic diversity, high inbreeding estimates and a depletion of heterozygotes, which together indicate a predominantly clonal breeding system, but signs of sexual events are also present. Three populations were identified from the clustering analysis, and they were well supported by F statistics inferences and partially corroborated by distance-based. POP1 (111 strains) was observed in all but one endemic area. POP2 (31 strains) is also well-dispersed, but it was the predominant population in Mato Grosso (MT). POP3 (31 strains) was less dispersed, and it was observed primarily in Mato Grosso do Sul (MS). Strains originated from an outbreak of canine VL in Southern Brazil were grouped in POP1 with those from Paraguay, which corroborates the hypothesis of dispersal from Northeastern Argentina and Paraguay. The distribution of VL in MS seems to follow the west-east construction of the Bolivia-Brazil pipeline from Corumbá municipality. This may have resulted in a strong association of POP3 and Lutzomyia cruzi, which is the main VL vector in Corumbá, and a dispersion of this population in this region that was shaped by human interference. This vector also occurs in MT and may influence the structure of POP2. This paper presents significant advances in the understanding of the population structure of L. infantum in Brazil and its association with eco-epidemiological aspects of VL
Peridomiciliary colonies of Triatoma vitticeps (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi in rural areas of the state of EspĂrito Santo, Brazil
In Brazil, the colonization of human dwellings by triatomines occurs in areas with native vegetation of the caatinga or cerrado types. In areas of Atlantic forest such as in the Brazilian state of EspĂrito Santo, there are no species adapted to live in human habitations. The few autochthonous cases of Chagas disease encountered in EspĂrito Santo have been attributed to adult specimens of Triatoma vitticeps that invade houses from forest remnants. In recent years, the entomology unit of the EspĂrito Santo State Health Secretariat has recorded nymphs infected with flagellates similar to Trypanosoma cruzi in rural localities. Entomological surveys were carried out in the residences and outbuildings in which the insects were found, and serological examinations for Chagas disease performed on the inhabitants. Four colonies were found, all associated with nests of opossums (Didelphis aurita), 111 specimens of T. vitticeps, and 159 eggs being collected. All the triatomines presented flagellates in their frass. Mice inoculated with the faeces presented trypomastigotes in the circulating blood and groups of amastigotes in the cardiac muscle fibres. Serological tests performed on the inhabitants were negative for T. cruzi. Even with the intense devastation of the forest in EspĂrito Santo, there are no indications of change in the sylvatic habits of T. vitticeps. Colonies of this insect associated with opossum nests would indicate an expansion of the sylvatic environment into the peridomicile
Peridomiciliary Breeding Sites of Phlebotomine Sand Flies (Diptera: Psychodidae) in an Endemic Area of American Cutaneous Leishmaniasis in Southeastern Brazil
Occurrence of multiple genotype infection caused by Leishmania infantum in naturally infected dogs.
Genetic polymorphisms in natural Leishmania populations have been reported in endemic areas. Microsatellite typing is a useful tool to elucidate the genetic variability of parasite strains, due to its capability for high-resolution mapping of genomic targets. The present study employed multilocus microsatellite typing (MLMT) to explore the genotypic composition of Leishmania infantum in naturally infected dogs by genotyping parasites infecting different tissues with or without in vitro expansion. Eighty-six samples were collected from 46 animals in an endemic region of visceral leishmaniasis (VL). MLMT was performed for 38 spleen samples and 48 L. infantum cultures isolated from different tissues. Of the 86 samples, 23 were effectively genotyped by MLMT, identifying nine multilocus genotypes (MLG; referred to as MLG A-I). MLGs A, B and C were detected in more than one type of tissue and in more than one sample. Conversely, MLG D-I were uniquely detected in one sample each. The results showed that multiple genotype infections occur within a single host and tissue. Paired sample analysis revealed the presence of different MLMT alleles in 14 dogs, while the same MLG allele was present in 15 animals. STRUCTURE analysis demonstrated the presence of two populations; 13 samples displayed a similar admixture of both ancestral populations, and these were not assigned to any population. Only samples for which Q ≥ 0.70 after CLUMPP alignment were considered to be part of Population 1 (POP1) or Population 2 (POP2). POP2 comprised the majority of samples (n = 54) compared to POP1 (n = 19). This study presents evidence of multiple genotype infections (caused by L. infantum) in dogs in an area with high VL transmission. Further investigations must be undertaken to determine the effects of multiple infection on the host immune response and disease dynamics and treatment
SHORT COMMUNICATION- Peridomiciliary colonies of Triatoma vitticeps (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi  in rural areas of the state of EspĂrito Santo, Brazil
In Brazil, the colonization of human dwellings by triatomines occurs in
areas with native vegetation of the caatinga or cerrado types. In areas
of Atlantic forest such as in the Brazilian state of EspĂrito
Santo, there are no species adapted to live in human habitations. The
few autochthonous cases of Chagas disease encountered in EspĂrito
Santo have been attributed to adult specimens of Triatoma vitticeps
 that invade houses from forest remnants. In recent years, the
entomology unit of the EspĂrito Santo State Health Secretariat has
recorded nymphs infected with flagellates similar to Trypanosoma cruzi
 in rural localities. Entomological surveys were carried out in
the residences and outbuildings in which the insects were found, and
serological examinations for Chagas disease performed on the
inhabitants. Four colonies were found, all associated with nests of
opossums (Didelphis aurita  ), 111 specimens of T. vitticeps,
and 159 eggs being collected. All the triatomines presented flagellates
in their frass. Mice inoculated with the faeces presented
trypomastigotes in the circulating blood and groups of amastigotes in
the cardiac muscle fibres. Serological tests performed on the
inhabitants were negative for T. cruzi. Even with the intense
devastation of the forest in EspĂrito Santo, there are no
indications of change in the sylvatic habits of T. vitticeps. Colonies
of this insect associated with opossum nests would indicate an
expansion of the sylvatic environment into the peridomicile