RESUMO

Los insectos relacionados con la transmisión de los patógenos causantes de las leishmaniasis han sido poco estudiados en la Sierra Nevada de Santa Marta, Colombia, incluido el departamento de Magdalena, donde a la fecha están registradas trece especies del género Lutzomyia. En la presente nota se informa el hallazgo de tres especies y un subgénero adicionales en la región. Se recolectaron 885 flebotomíneos en Seywiaka y las veredas Las Tinajas y Calabazo, estribaciones de la Sierra Nevada de Santa Marta (117-130 m s.n.m.). El 84 % de los ejemplares se obtuvieron con trampa CDC, el 11 % con trampa Shannon y el 5 % fueron capturados, en reposo, con un dispositivo eléctrico de succión. Se identificaron nueve especies, Lu. gomezi, Lu. panamensis, Lu. trinidadensis, Lu. carpenteri, Lu. evansi, Lu. dysponeta, Lu. dubitans, Lu. shannoni, y Lu. micropyga, la más abundante fue Lu. gomezi (69 %), seguida por Lu. panamensis (14 %). También se recolectaron ejemplares de la serie Lu. osornoi del subgénero Helcocyrtomyia. Entre el material hallado sobresalen Lu. carpenteri, Lu. dubitans y Lu. dysponeta como primeros registros para el departamento del Magdalena, además de Lu. (Helcocyrtomyia) sp., que representa el primer informe del subgénero en el Caribe colombiano.

Phlebotomine sand flies, vectors of leishmaniasis, have not been well studied in the Sierra Nevada de Santa Marta, and likewise, are not well known in other regions of the Department of Magdalena, Colombia. To date only thirteen species of Lutzomyia have been recorded as occurring in the Department. The present note adds three species and includes an additional subgenus. Collections were made in the lower foothills of the Sierra Nevada de Santa Marta at elevations ranging from 117-130 m in the communities of Seywiaka, Las Tinajas and Calabazo. Eighty-four percent of the 885 phlebotomines sand flies collected were obtained from CDC light traps, 11 % from Shannon trap and 5 % from typical resting sites using an electric aspirator. The following nine species were identified from the collections: Lutzomyia gomezi, Lu. panamensis, Lu. trinidadensis, Lu. carpenteri, Lu. evansi, Lu. dysponeta, Lu. dubitans, Lu. shannoni, and Lu. micropyga. The most abundant species were Lu. gomezi and Lu. panamensis, which, respectively, accounted for 69 % and 14 % of the specimens. Of the nine species, Lu. carpenteri, Lu. dubitans and Lu. dysponeta represent new records for the Department of Magdalena. Also, a few female specimens were encountered of a species belonging to the Lu. osornoi series of the subgenus Helcocyrtomyia, which represents the first record of this subgenus in the Caribbean region of Colombia.

RESUMO

Sand flies include a group of insects that are of medical importance and that vary in geographic distribution, ecology, and pathogen transmission. Approximately 163 species of sand flies have been reported in Colombia. Surveillance of the presence of sand fly species and the actualization of species distribution are important for predicting risks for and monitoring the expansion of diseases which sand flies can transmit. Currently, the identification of phlebotomine sand flies is based on morphological characters. However, morphological identification requires considerable skills and taxonomic expertise. In addition, significant morphological similarity between some species, especially among females, may cause difficulties during the identification process. DNA-based approaches have become increasingly useful and promising tools for estimating sand fly diversity and for ensuring the rapid and accurate identification of species. A partial sequence of the mitochondrial cytochrome oxidase gene subunit I (COI) is currently being used to differentiate species in different animal taxa, including insects, and it is referred as a barcoding sequence. The present study explored the utility of the DNA barcode approach for the identification of phlebotomine sand flies in Colombia. We sequenced 700 bp of the COI gene from 36 species collected from different geographic localities. The COI barcode sequence divergence within a single species was <2% in most cases, whereas this divergence ranged from 9% to 26.6% among different species. These results indicated that the barcoding gene correctly discriminated among the previously morphologically identified species with an efficacy of nearly 100%. Analyses of the generated sequences indicated that the observed species groupings were consistent with the morphological identifications. In conclusion, the barcoding gene was useful for species discrimination in sand flies from Colombia.

Assuntos

RESUMO

Two snapshot surveys to establish the diversity and ecological preferences of mosquitoes (Diptera: Culicidae) in the terra firme primary rain forest surrounding the Tiputini Biodiversity Station in the UNESCO Yasuní Biosphere Reserve of eastern Amazonian Ecuador were carried out in November 1998 and May 1999. The mosquito fauna of this region is poorly known; the focus of this study was to obtain high quality link-reared specimens that could be used to unequivocally confirm species level diversity through integrated systematic study of all life stages and DNA sequences. A total of 2,284 specimens were preserved; 1,671 specimens were link-reared with associated immature exuviae, all but 108 of which are slide mounted. This study identified 68 unique taxa belonging to 17 genera and 27 subgenera. Of these, 12 are new to science and 37 comprise new country records. DNA barcodes [658-bp of the mtDNA cytochrome c oxidase (COI) I gene] are presented for 58 individuals representing 20 species and nine genera. DNA barcoding proved useful in uncovering and confirming new species and we advocate an integrated systematics approach to biodiversity studies in future. Associated bionomics of all species collected are discussed. An updated systematic checklist of the mosquitoes of Ecuador (n=179) is presented for the first time in 60 years.

Assuntos

RESUMO

Two snapshot surveys to establish the diversity and ecological preferences of mosquitoes (Diptera: Culicidae) in the terra firme primary rain forest surrounding the Tiputini Biodiversity Station in the UNESCO Yasuní Biosphere Reserve of eastern Amazonian Ecuador were carried out in November 1998 and May 1999. The mosquito fauna of this region is poorly known; the focus of this study was to obtain high quality link-reared specimens that could be used to unequivocally confirm species level diversity through integrated systematic study of all life stages and DNA sequences. A total of 2,284 specimens were preserved; 1,671 specimens were link-reared with associated immature exuviae, all but 108 of which are slide mounted. This study identified 68 unique taxa belonging to 17 genera and 27 subgenera. Of these, 12 are new to science and 37 comprise new country records. DNA barcodes [658-bp of the mtDNA cytochrome c oxidase ( COI ) I gene] are presented for 58 individuals representing 20 species and nine genera. DNA barcoding proved useful in uncovering and confirming new species and we advocate an integrated systematics approach to biodiversity studies in future. Associated bionomics of all species collected are discussed. An updated systematic checklist of the mosquitoes of Ecuador (n = 179) is presented for the first time in 60 years.

Assuntos

RESUMO

To eliminate transmission of Onchocerca volvulus, semiannual mass treatment with ivermectin (Mectizan; donated by Merck & Co) has been underway in Guatemala since 2000. We applied the 2001 World Health Organization (WHO) elimination criteria in the Santa Rosa focus of onchocerciasis transmission in Guatemala (10,923 persons at risk). No evidence of parasite DNA was found in 2,221 Simulium ochraceum vectors (one-sided 95% confidence interval [CI], 0-0.086%), and no IgG4 antibody positives to recombinant antigen OV16 were found in a sample of 3,232 school children (95% CI, 0-0.009%). We also found no evidence of microfilariae in the anterior segment of the eye in 363 area residents (95% CI, 0-0.08%). Our interpretation of these data, together with historical information, suggest that transmission of O. volvulus is permanently interrupted in Santa Rosa and that ivermectin treatments there can be halted.

Assuntos

RESUMO

We focus on possible constraints upon Onchocerca volvulus establishment in humans in relation to exposure rates to infective larvae (L3) as measured by the annual transmission potential (ATP). We use mathematical and statistical modeling of pre-control west African (savanna), Mexican, and Guatemalan data to explore two hypotheses relating human infection to transmission intensity: microfilarial (mf) loads either saturate with increasing ATP or become (asymptotically) proportional to the ATP. The estimated proportion of L3 developing into adult worms ranged from 7% to 0.3% (low and high intensity areas, respectively). Relationships between mf prevalence and both mf and transmission intensity were nonlinear and statistically similar between west Africa (Simulium damnosum s.l.) and Meso America (S. ochraceum s.l.). This similarity extended to the relationship between mf intensity and ATP. The critical biting rates for onchocerciasis introduction and persistence (which depended on vector competence and host preference), were approximately 10-fold higher in settings where onchocerciasis is transmitted by S. ochraceum than in those where the vector is S. damnosum. A role for focal vector control in Mexico and Guatemala, in addition to nodulectomy and ivermectin, is suggested.

Assuntos