RESUMO
We evaluated the ecological and epidemiological aspects of the sand fly fauna in an area of the Atlantic Forest biome with records of visceral and cutaneous leishmaniasis. Sand fly collections at three different localities at the National Monument of Pontões Capixabas, State of Espírito Santo, Southeastern Brazil, were conducted by using two Centers of Disease Control and Prevention automatic light traps in the peridomiciliary environment and eight Centers of Disease Control and Prevention automatic light traps in the forested environment. Collections occurred during four consecutive nights within each of the months and locations: São Luiz (December 2009, May 2010, July 2010, and December 2010), Córrego Palmital de Baixo (September 2010 and October 2010), and Córrego São Bento (February 2011 and May 2011). We collected 21,138 sand flies belonging to 31 species and 14 genera. Of this total, 12,412 sand flies were captured in the peridomiciliary environment and 8,726 in the forested environment. All of the vector species, Lutzomyia longipalpis (=Lutzomyia longipalpis, sensu; Young and Duncan), Migonemyia migonei (=Lutzomyia migonei, sensu; Young and Duncan), and Nyssomyia intermedia (=Lutzomyia intermedia, sensu; Young and Duncan), occurred in significantly higher numbers in the peridomiciliary environment than compared with the forested environment. Our results highlight the importance of conservation in the forest remains of the National Monument of Pontões Capixabas, because of higher species richness and diversity. Furthermore, they indicate the epidemiological role of Lu. longipalpis as the vector of Leishmania infantum within the study area, and the no evident role of Mg. migonei.
Assuntos
Biodiversidade , Insetos Vetores/fisiologia , Psychodidae/fisiologia , Animais , Brasil/epidemiologia , Meio Ambiente , Feminino , Humanos , Insetos Vetores/parasitologia , Leishmania infantum/fisiologia , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/parasitologia , Masculino , Dinâmica Populacional , Psychodidae/classificação , Psychodidae/parasitologia , Estações do AnoRESUMO
To assess the effect of the rapid removal of potentially infectious dogs on the prevalence and incidence of canine infections, a prospective study was undertaken in an area endemic for Leishmania infantum. We used serological testing based on the rapid DPP rK28 fusion protein chromatographic immunoassay for this dog screening-and-culling intervention trial. The outcome was evaluated by measuring seropositivity and sero-conversion/-reversion rates for canine infection. Our estimates indicated that concomitant detection and elimination of seropositive dogs with active disease may affect the numbers of canine infections and disease burden temporarily, although it is insufficient as a measure to interrupt the zoonotic L. infantum transmission. However, most of the asymptomatic, seropositive dogs continuously exhibit low levels of antibodies and/or reverted, remaining seronegative thereafter. In the process of waiting for an effective vaccine, one option for canine reservoir control may be to identify these possibly genetically resistant animals and promote their expansion in the population.
Assuntos
Doenças do Cão/epidemiologia , Doenças do Cão/transmissão , Leishmania infantum/crescimento & desenvolvimento , Leishmaniose Visceral/veterinária , Animais , Brasil/epidemiologia , Reservatórios de Doenças/parasitologia , Reservatórios de Doenças/veterinária , Doenças do Cão/diagnóstico , Doenças do Cão/parasitologia , Cães , Incidência , Leishmania infantum/patogenicidade , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/transmissão , Prevalência , Estudos ProspectivosRESUMO
Canine visceral leishmaniasis (CVL) is the major source of human visceral leishmaniasis (VL) and is transmitted from dogs to sand flies to humans. To control the spread of this disease, early and accurate detection of infected dogs is critical but challenging. Here we demonstrate the potential of the Dual-Path Platform (DPP(®)) CVL rapid test for detecting K26/K39-reactive antibodies in sera from clinically symptomatic (n=60) and asymptomatic (n=60) Leishmania infantum-infected dogs. For the specificity evaluation, assays were performed using known negative diagnostic serum samples (n=59) and cross-reaction control sera (n=11) from animals born in a VL-free area of Brazil. The diagnostic kit displayed high specificity (96%) but low sensitivity (47%) in identifying parasite-positive dogs without signs of CVL. However, the test sensitivity was significantly higher (98%) in diseased cases, indicating that this convenient test may be useful to identify the most infectious dogs. Efforts should be pursued to obtain a more sensitive DPP-multiplexed test parameter (i.e. based on simultaneous yet separate antibody detection of carefully selected multiple antigens of diagnostic utility) for effective serodiagnosis of early-infected dogs, as this will likely allow more efficient canine removal regimens than those used in practice by public health services.
Assuntos
Anticorpos Antiprotozoários/isolamento & purificação , Cromatografia , Doenças do Cão/diagnóstico , Imunoensaio , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/veterinária , Animais , Cromatografia/veterinária , Doenças do Cão/parasitologia , Cães , Imunoensaio/veterinária , Leishmania infantum/imunologia , Leishmaniose Visceral/diagnóstico , Sensibilidade e Especificidade , Testes Sorológicos/veterináriaRESUMO
This paper describes sand flies similar to Nyssomyia intermedia (Lutz & Neiva) with variations in the number of spines at the gonostyle and tests the hypothesis whether these specimens belong or not to N. intermedia species. Using Principal Component Analysis and Neighbour Joining, the measurements of 15 structures of the phlebotomine with variations in number of spines were compared with measurements of 30 sand flies of N. intermedia species. Both analyses didn't cluster the specimens with variation in spines number in one group and provided evidence to the hypothesis that those sand flies belong to N. intermedia.
Assuntos
Psychodidae/anatomia & histologia , Animais , Psychodidae/classificaçãoRESUMO
This paper describes sand flies similar to Nyssomyia intermedia (Lutz & Neiva) with variations in the number of spines at the gonostyle and tests the hypothesis whether these specimens belong or not to N. intermedia species. Using Principal Component Analysis and Neighbour Joining, the measurements of 15 structures of the phlebotomine with variations in number of spines were compared with measurements of 30 sand flies of N. intermedia species. Both analyses didn't cluster the specimens with variation in spines number in one group and provided evidence to the hypothesis that those sand flies belong to N. intermedia.
Assuntos
Animais , Psychodidae/anatomia & histologia , Psychodidae/classificaçãoRESUMO
In this study, we sought to identify sand fly vectors of the Leishmania species that circulate in distinct eco-epidemiological disease-endemic rural areas within the Espírito Santo State in southeastern Brazil. PCR amplification of a conserved region of the minicircle kDNA was used to estimate infection rates in field-captured, peridomestic female sand flies. Only 13 of the 1689 female sand fly specimens (0.77%) actually contained Leishmania DNA. Leishmania braziliensis infections were found in Lutzomyia intermedia and Lu. whitmani, and, for the first time, in Lu. fischeri and Lu. ferreirana. Interestingly, the high rate of genetic polymorphism of the L. braziliensis parasites in one of the disease-endemic areas that were studied may reflect specific transmission cycles involving different sand fly vectors.
Assuntos
Leishmania braziliensis/isolamento & purificação , Psychodidae/parasitologia , Animais , Brasil , Feminino , Leishmania braziliensis/genética , Leishmania braziliensis/crescimento & desenvolvimento , Reação em Cadeia da Polimerase , Polimorfismo Genético , Densidade Demográfica , Psychodidae/classificação , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
In an endemic rural area of southeast Brazil, surveys confirmed that dogs serve as peridomestic reservoirs of Leishmania infantum. It is likely that the lack of efficient control is because presently used diagnostic tests miss positive dogs. Overall, 57% of the dogs had specific antibodies, but the canine infection was not uniformly fatal and many seropositive dogs remained asymptomatic or even spontaneously recovered. Furthermore, 42% of the human residents became leishmanin-positive reactors and 47% had positive serology at the initial survey, but our estimates also point at a high recovery rate among the infected population with time. The delayed-type hypersensitivity (DTH) reaction to Leishmania was a good indicator of resistance to infection in this particular epidemiologic situation. The lack of any significant differences in infection rates by gender or age indicate that all of the population was at an equal risk of infection and most people were infected in the peridomestic setting.
Assuntos
Doenças do Cão/epidemiologia , Doenças Endêmicas/estatística & dados numéricos , Leishmania infantum , Leishmaniose Visceral/epidemiologia , Zoonoses/epidemiologia , Adolescente , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Criança , Estudos Transversais , Reservatórios de Doenças , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Leishmania infantum/imunologia , Leishmaniose Visceral/transmissão , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , População Rural , Adulto Jovem , Zoonoses/transmissãoRESUMO
The diagnosis of visceral leishmaniasis remains difficult in rural areas where the disease is endemic, and serologic methods still need assessment, as they are not very sensitive for the detection of asymptomatic infectious dogs. Here we present data on the development of enzyme-linked immunosorbent assay (ELISA)-based methods for the detection of antibodies against recombinant leishmanial antigens (namely, the recombinant K26 [rK26] and rK39 antigens from Leishmania infantum and the rA2 protein from Leishmania donovani) in comparison to ELISAs employing crude soluble antigen (CSA). The assays utilized sera from known negative controls (n=25) and clinically asymptomatic (n=50) and symptomatic (n=50) dogs with confirmed L. infantum infections. Additional studies were also done using sera from animals harboring other infections (n=14) for the evaluation of cross-reactivity. Our study indicated that rK26 and rK39 used in ELISAs provided very high sensitivities for the detection of symptomatic dogs (94% and 100%, respectively), followed by CSA (88%) and rA2 (70%). Conversely, rA2 was more sensitive for asymptomatic dogs (88%) than rK39 and rK26 (both 66%) and CSA (30%). Some cross-reactivity in sera from dogs with other infections (Leishmania braziliensis and Leptospira interrogans) was identified, but the rA2 protein provided the greatest specificity (98%). Data further indicate that all three recombinant proteins must be used in parallel to detect essentially all infected dogs. Efforts should be made to develop a cheap and reliable serologic test based on epitope selection from these diagnostic markers for the sensitive detection of L. infantum-infected dogs.