RESUMO
In Guatemala, the most widespread vector of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae), the causative agent of Chagas disease, is Triatoma dimidiata (Latreille) (Hemiptera: Reduviidae: Triatominae). T. dimidiata is native to Guatemala and is present in both domestic and sylvatic habitats. Consequently, control of T. dimidiata is difficult because after successful elimination from homes, individual insects can recolonize homes from the surrounding environment. Therefore, intensive long-term surveillance of this species is essential to ensure adequate control is achieved. Manual inspection for signs of infestation, the current method used to monitor Triatominae throughout Central and South America, is labor and time-consuming, so cost-effective alternatives are needed. The current study compared the effectiveness of the current method of surveillance of T. dimidiata with community-based techniques of G6mez-Nuñez sensor boxes, collection and observation of bugs by householders, and presence of triatomine-like feces on walls. Although manual inspection was the most sensitive method when used alone, collection by householders also was sensitive and specific and involved less effort. Sensor boxes were not sensitive indicators of T. dimidiata infestation when used alone. Two recorded variables, visual inspection for feces and the sighting of bugs by householders, were sensitive and specific indicators of infestation, and in combination with collection by householders and sensor boxes these methods were significantly more likely to detect infestations than manual inspection alone. A surveillance program that combines multiple community-based techniques should have low cost and involve minimal effort from the government and at the same time promote sustainable community involvement in disease prevention.
Assuntos
Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Triatoma/parasitologia , Animais , GuatemalaRESUMO
Despite decades of research, there is still no agreement on which indices of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) presence and abundance better quantify entomological risk for dengue. This study reports the results of a multi-scale, cross-sectional entomological survey carried out in 1160 households in the city of Merida, Mexico to establish: (a) the correlation between levels of Ae. aegypti presence and abundance detected with aspirators and ovitraps; (b) which immature and egg indices correlate with the presence and abundance of Ae. aegypti females, and (c) the correlations amongst traditional Aedes indices and their modifications for pupae at the household level and within medium-sized geographic areas used for vector surveillance. Our analyses show that ovitrap positivity was significantly associated with indoor adult Ae. aegypti presence [odds ratio (OR) = 1.50; P = 0.03], that the presence of pupae is associated with adult presence at the household level (OR = 2.27; P = 0.001), that classic Aedes indices are informative only when they account for pupae, and that window screens provide a significant level of protection against peridomestic Ae. aegypti (OR = 0.59; P = 0.02). Results reinforce the potential of using both positive collections in outdoor ovitraps and the presence of pupae as sensitive indicators of indoor adult female presence.
Assuntos
Aedes/fisiologia , Monitoramento Ambiental , Insetos Vetores/fisiologia , Aedes/crescimento & desenvolvimento , Animais , Estudos Transversais , Dengue/epidemiologia , Dengue/parasitologia , Feminino , Insetos Vetores/crescimento & desenvolvimento , Larva/fisiologia , México , Controle de Mosquitos , Óvulo/fisiologia , Densidade Demográfica , Pupa/fisiologiaRESUMO
In Guatemala prior to control initiatives, the main vectors of Trypanosoma cruzi, the causative agent of Chagas disease, were Rhodnius prolixus and Triatoma dimidiata. This study conducted in 2006 in the department of Chiquimula recorded a high level of T. dimidiata infestation and an absence of R. prolixus in all surveyed communities. In Guatemala, the presence of T. dimidiata as domestic, peridomestic and sylvatic populations results in control difficulties as houses are re-infested from the surrounding environment. Entomological surveys, the current method used to select houses in need of control efforts, are labour intensive and time consuming. A time- and cost-effective way to prioritize houses for evaluation and subsequent treatment is the stratification of houses based on the risk of triatomine infestation. In the present study, 17 anthropogenic risk factors were evaluated for associations with house infestation of T. dimidiata including: wall, floor and roof type. There was an increased likelihood of domestic infestation with T. dimidiata associated with the presence of dirt floors (18/29; OR 8.075, 95% CI 2.13-30.6), uncoated bajareque walls (12/17; OR 4.80, 95% CI 1.35-17.1) and triatomine-like faeces on walls (16/26; OR 3.89, 95% CI 1.19-12.7). These factors could be used to target control of T. dimidiata to communities with an increased risk of being infested.
Assuntos
Habitação/estatística & dados numéricos , Insetos Vetores , Triatoma , Animais , Doença de Chagas/transmissão , Guatemala , Fatores de RiscoRESUMO
BACKGROUND: Heart disease is a frequent complication of chronic kidney disease and the major cause of death in patients on renal replacement therapy. The purpose of this study was to evaluate the impact of successful kidney transplantation on systolic and diastolic ventricular dysfunction and pulmonary arterial hypertension in patients with chronic kidney disease (CKD). METHODS: The study included 35 patients >18 years of age with CKD who had successful kidney transplantations. Ventricular function and pulmonary arterial pressure were evaluated by echocardiography before and 1 year after transplant. RESULTS: The mean age of subjects was 40 ± 14 years, and 63% were men. Mean left ventricular ejection fraction (LVEF) was 52 ± 16%. Before transplant, 28 (80%) of the patients had ventricular dysfunction (34.3% diastolic and 45.7% systolic). Pulmonary arterial hypertension was found in 48.6%. Ventricular dysfunction was associated with dialysis of >2 years duration before transplant. The LVEF of the entire group increased from 52% to 64% (P < .001) by 12 months after kidney transplant. Left ventricular diameters, wall thickness, and pulmonary arterial systolic pressure decreased significantly after transplantation Echocardiograms became normal 1 year after transplant in 8 (66.7%) of the patients with diastolic dysfunction and 9 (56.2%) with systolic dysfunction, and diastolic dysfunction persisted in 5 (31.2%). CONCLUSIONS: Because kidney transplantation led to considerable improvement in left ventricular systolic and diastolic function as well as pulmonary arterial pressure of patients with CKD, optimal treatment for dysfunction and transplant as soon as possible is recommended.
Assuntos
Hipertensão Pulmonar/etiologia , Falência Renal Crônica/cirurgia , Transplante de Rim , Disfunção Ventricular Esquerda/etiologia , Adulto , Pressão Sanguínea , Ecocardiografia Doppler , Feminino , Humanos , Hipertensão Pulmonar/diagnóstico por imagem , Hipertensão Pulmonar/fisiopatologia , Falência Renal Crônica/complicações , Falência Renal Crônica/fisiopatologia , Masculino , México , Pessoa de Meia-Idade , Estudos Prospectivos , Recuperação de Função Fisiológica , Volume Sistólico , Fatores de Tempo , Resultado do Tratamento , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular EsquerdaRESUMO
BACKGROUND: Chagas disease, transmitted domestically by triatomine bugs, is the most important vector-borne disease in Latin America. The association between triatomine infestation and housing characteristics was investigated based on a standardized survey in 41 971 houses in 15 Departments in Colombia. METHODS: Multivariate logistic regression was used to test for associations of two highly correlated infestation measures of infestation (householders reporting having seen triatomines inside the house, and sending triatomines to the survey team), with 15 household-level risk factors. Risks were measured relative to a reference category of houses with up to three inhabitants, area up to 50 m(2), unplastered adobe walls, thatch roof and no outbuildings or domestic animals. RESULTS: The probability of seeing triatomines was highest for households with over seven inhabitants (OR = 1.24, 95% CI 1.11-1.39), overhead storage space (OR = 1.16, 95% CI 1.03-1.32), grain shed (OR = 1.25, 95% CI 1.02-1.52), cats (OR = 1.27, 95% CI 1.14-1.42) and pigs (OR = 1.16, 95% CI 1.03-1.30). Lowest risks were in houses with wooden walls (OR = 0.46, 95% CI 0.34-0.61), fully plastered walls (OR = 0.78, 95% CI 0.68-0.88), roofs made of tiles (OR = 0.51, 95% CI 0.33-0.78) and flagstone floors (OR = 0.57, 95% CI 0.42-0.76). Results for householders returning triatomines support this set of risk factors, but with wider confidence intervals. CONCLUSIONS: Surveillance of a few easily assessed household characteristics provides an accurate, rapid assessment of house-level variation in risk. Measured effect sizes for specific structural characteristics could be used to maximize the cost-effectiveness of programmes to reduce vector infestation and interrupt Chagas disease transmission by improving house quality.
Assuntos
Doença de Chagas/transmissão , Habitação , Insetos Vetores , Rhodnius , Animais , Animais Domésticos , Doença de Chagas/prevenção & controle , Colômbia , Ectoparasitoses , Inquéritos Epidemiológicos , Abrigo para Animais , Humanos , Análise Multivariada , Razão de Chances , Probabilidade , Medição de Risco/métodos , Fatores de RiscoRESUMO
Outside sub-Saharan Africa, Anopheline mosquito exophagic and/or crepuscular behaviour patterns imply that insecticide-treated nets may provide incomplete protection from malaria-infective mosquito bites. Supplementary repellent treatment has been recommended in such circumstances, especially where vectors are exophilic and so are not susceptible to residual insecticide spraying. As maintaining complete usage of repellents in a community is unrealistic, the potential negative impact on non-users of repellent usage by 'neighbours' in the same community needs to be addressed in the context of health policy promoting equity. This study quantifies diversion of host-seeking mosquitoes, from repellent wearing to unprotected individuals, 1 m apart under field conditions in Bolivia. Each of the six volunteer-pairs sat >20 m apart from other pairs. Volunteers were allocated di-ethyl toluamide (DEET) or mineral oil in ethanol control. Treatments were rotated, so that during the trial, both pair-members wore repellent on 72 occasions; both pair-members wore control on 72 occasions; and on 36 occasions, one pair-member wore repellent and the other control. Unprotected (control) pair-members received 36.4% [95% confidence interval (CI): 8.1-72.0%] more Anopheles darlingi landings (P = 0.0096) and 20.4% (95% CI: 0.6-44.0%) more mosquito landings (P = 0.044), when their 'partner' wore repellent than when their partner also wore control. A second, smaller Latin-square trial using 30% lemongrass (Cymbopogon citratus) repellent, with control, obtained 26.0% (95% CI: 5.2-51.0%) more mosquito landings when controls sat with repellent-wearers rather than other controls (P = 0.0159). With incomplete community repellent usage, non-users could be put at an increased risk of malaria. The results also have implications for repellent-efficacy assay design, as protection will appear magnified when mosquitoes are given a choice between repellent-users and non-users.
Assuntos
Anopheles/efeitos dos fármacos , DEET/administração & dosagem , Repelentes de Insetos/administração & dosagem , Insetos Vetores/efeitos dos fármacos , Animais , Anopheles/fisiologia , Bolívia/epidemiologia , Cymbopogon/fisiologia , Comportamento Alimentar/fisiologia , Humanos , Mordeduras e Picadas de Insetos/epidemiologia , Insetos Vetores/fisiologia , Malária/epidemiologia , Malária/prevenção & controle , Malária/transmissão , Medição de RiscoRESUMO
Domestic dogs (Canis familiaris) are firmly incriminated as reservoir hosts of zoonotic visceral leishmaniasis. As an increasing number of studies have reported high infection rates with American cutaneous leishmaniasis (ACL) in dogs, it is suggested that they should also be incriminated as reservoir hosts of ACL. The evidence to incriminate dogs as ACL reservoir hosts is reviewed, and we conclude that there is, as yet, only circumstantial evidence to support that claim, one of the reasons being that diagnostic tests (mainly serology) used in the studies underestimate the true rate of infection. We report results from the first large-scale study to measure ACL infection rates using the polymerase chain reaction (PCR). A high prevalence of ACL was detected in blood and bone marrow of dogs surveyed in an area of Peru endemic for Leishmania braziliensis and L. peruviana, providing further evidence for their suspected role as ACL reservoir hosts. However, the relatively low ACL prevalence detected in symptomatic dogs (i.e., dogs with ACL lesions or scars) demonstrated that PCR alone cannot be the diagnostic 'gold standard' for mass screening of samples in epidemiological studies.
Assuntos
Doenças do Cão/epidemiologia , Leishmaniose Cutânea/veterinária , Programas de Rastreamento/veterinária , Reação em Cadeia da Polimerase/veterinária , Animais , Reservatórios de Doenças , Doenças do Cão/diagnóstico , Cães , Insetos Vetores/parasitologia , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/epidemiologia , Programas de Rastreamento/métodos , Peru/epidemiologia , Reação em Cadeia da Polimerase/métodos , Prevalência , Psychodidae/parasitologiaRESUMO
The prevalence of human infection by Trypanosoma cruzi was assessed using an enzyme-linked immunosorbent assay (ELISA) in a serological survey in 1998 of 2 rural communities (SMH and PS) in Guatemala. In SMH (Department of Zacapa), where Rhodnius prolixus was the principal vector, the seroprevalence amongst 373 people tested was 38.8%. In PS (Department of Santa Rosa), where the main vector was Triatoma dimidiata, 8.9% of the 428 people tested were seropositive. The overall prevalence of seropositivity was higher in females than in males in both SMH (40% vs 36%) and PS (11.9% vs 4.9%), although this difference was significant only in PS. Historical seroconversion rates, estimated retrospectively by fitting a transmission model to the age-prevalence curves, were 3.8% per year in SMH and 0.5% per year in PS. There was some indication of a recent reduction in incidence in both villages. In PS, but not in SMH, both the observed prevalence and the estimated incidence rates were significantly higher in females than in males.
Assuntos
Doença de Chagas/epidemiologia , Trypanosoma cruzi , Adolescente , Adulto , Distribuição por Idade , Idoso , Animais , Criança , Pré-Escolar , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Guatemala/epidemiologia , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Prevalência , Saúde da População Rural , Distribuição por SexoRESUMO
Mathematical models often propose that within-host competition between parasites can be a major factor in the evolution of increased parasite virulence. Kin selection predicts that as the coefficient of relatedness between infecting parasites decreases, the benefits of competition to individual genotypes increases. Thus where parasites can adjust their behaviour in response to current conditions, higher virulence is predicted in multiple genotype infections. There is limited experimental data, however, regarding the effects of mixed strain infections on host and parasite fitness. We investigated, for a snail-schistosome system, whether a conditional increase in replication rates occurred in mixed genotype infections and resulted in increased virulence. Four groups of Biomphalaria glabrata snails were exposed to 1 or 2 laboratory strains of Schistosoma mansoni. Mixed genotype infections were observed to be more virulent than single genotype infections, in terms of reductions in host reproductive success and survival. Parasite reproductive rate was also increased in mixed strain groups. Reduced host reproductive success was suggested to be directly due to the genetic heterogeneity of the parasitic infections resulting in increased host defence costs. Reduced host survival was consistent with an adaptive conditional parasite response.
Assuntos
Evolução Biológica , Biomphalaria/parasitologia , Schistosoma mansoni/patogenicidade , Esquistossomose mansoni/parasitologia , Animais , Feminino , Quênia , Masculino , Camundongos , Camundongos Endogâmicos CBA , Porto Rico , Distribuição Aleatória , Schistosoma mansoni/genética , Schistosoma mansoni/crescimento & desenvolvimento , Esquistossomose mansoni/transmissão , Estatísticas não Paramétricas , VirulênciaRESUMO
Using a capture-recapture method, this study evaluates the completeness of the cutaneous leishmaniasis (CL) surveillance system in four districts of Santiago del Estero province, Argentina, for the period 1990-1993. Four reporting sources were evaluated: medical records kept by health facilities, interviews conducted during a case-control study, and the national and provincial levels of the leishmaniasis surveillance system (LSS). Using the capture-recapture method it was estimated that 210 cases (95% confidence interval [CI]: 202-218) of CL occurred in the four districts during the study period. Completeness of reporting to the leishmaniasis surveillance system at the national level was estimated to be 44.8% (95% CI: 43.2-46.4). The study results indicate that there is substantial underreporting within the LSS, although it did show the appropriate secular trends. The reasons for under-reporting and methods for addressing this problem are discussed.
Assuntos
Notificação de Doenças/normas , Leishmania/crescimento & desenvolvimento , Leishmaniose Cutânea/epidemiologia , Animais , Argentina/epidemiologia , Estudos de Casos e Controles , Intervalos de Confiança , Notificação de Doenças/métodos , HumanosRESUMO
Responses of Lutzomyia sandflies (Diptera: Psychodidae: Phlebotominae) to carbon dioxide (CO2) and human odour were investigated by field experiments in Parana State, southern Brazil. Catches of two predominant species: Lu. intermedia (Antunes & Coutinho) and Lu. whitmani Lutz & Neiva, were compared between traps baited with a human adult or with CO2 emitted at the human-equivalent rate. When the baits were only 40 cm apart, no difference of attractiveness was detected. When baits were separated by 20 m, however, significantly fewer sandflies (44% Lu. intermedia, 46% Lu. whitmani) were trapped with CO2 compared with human bait. This is the first field evidence that anthropophilic sandflies are attracted by human kairomones in addition to CO2. For both species [Lutzomyia intermedia and Lu. whitmani] [corrected], the proportion of human attractiveness attributable to CO2 was significantly more [corrected] for males than females; for Lu. intermedia males human bait was no more attractive than CO2 alone. Gender differences in sandfly olfactory sensitivity are likely to be associated with behavioural differences on the host, where females feed on blood and males find mates. With traps 20 m apart, both Lutzomyia spp. showed roughly linear increased responses (log-log scale) to 0.08-0.55% CO2 equivalent to 0.5-4 humans. This would explain why host size is generally proportional to attractiveness, as observed for other species of phlebotomine sandflies.
Assuntos
Dióxido de Carbono/fisiologia , Hormônios de Inseto/fisiologia , Odorantes , Psychodidae/fisiologia , Adulto , Animais , Comportamento Animal/fisiologia , Brasil , Dióxido de Carbono/farmacologia , Humanos , Hormônios de Inseto/farmacologia , Modelos Lineares , Masculino , Psychodidae/efeitos dos fármacos , Fatores SexuaisRESUMO
In stark contrast to the huge body of theoretical work on the importance of hosts and parasites as selective agents acting on each other, until recently, little systematic empirical investigation of this issue has been attempted. Research on snail-schistosome interactions have, therefore, the potential for making an important contribution to the study of coevolution or reciprocal adaptation. This may be particularly pertinent since snail-schistosomes represent an indirectly transmitted macroparasite system, so often overlooked amongst both theoretical and empirical studies. Here we review ideas and experiments on snail-schistosome interactions, with particular emphasis on those that may have relevance to the potential coevolution between host resistance and parasite infectivity and virulence. We commence with an introduction and definition of the general concepts, before going into detail of some specific studies to illustrate these: evidence of snail-schistosome coevolutionary process in the field; evidence of coevolutionary processes in the laboratory; a general assessment of the applicability of coevolutionary models in snail-schistosome interactions; and finishing with a section on conclusions and areas for further study.
Assuntos
Evolução Biológica , Biomphalaria/genética , Schistosoma mansoni/genética , Animais , Biomphalaria/parasitologia , Predisposição Genética para Doença , Variação Genética , Interações Hospedeiro-Parasita/genética , Modelos Biológicos , Porto Rico , Esquistossomose mansoni/genética , VirulênciaRESUMO
A PCR-based protocol for the detection of Leishmania (Viannia) parasites in canine blood, buffy coat, and bone marrow was developed and was then tested with field samples taken from a random sample of 545 dogs from villages in Peru where Leishmania (Viannia) braziliensis and Leishmania (Viannia) peruviana are endemic. Comparative tests with cultured parasites mixed with dog blood showed that the PCR assay's sensitivity was significantly dependent on the DNA extraction protocol and the PCR primers used. Mass screening of field samples by the preferred PCR protocol detected American cutaneous leishmaniasis (ACL) in 44 of 545 (8.1%) dogs; 31 of 402 (7.7%), 20 of 223 (9.0%), and 8 of 46 (17.4%) were PCR positive when whole blood, buffy coat, and bone marrow aspirates, respectively, were tested. The high prevalence of Leishmania in both asymptomatic (7.6%) and symptomatic (18.0%) dogs provides further circumstantial evidence for their suspected role as reservoir hosts of ACL and indicates that hematogenous dissemination of parasites may be a more common pathological phenomenon than has previously been acknowledged. However, unlike for zoonotic visceral leishmaniasis, the comparatively low prevalence of Leishmania (Viannia) in the blood of symptomatic dogs indicates that PCR with blood cannot be the "gold standard" for the (mass) screening of samples in epidemiological studies.
Assuntos
Medula Óssea/parasitologia , Doenças do Cão/diagnóstico , Leishmania/isolamento & purificação , Leishmaniose Cutânea/veterinária , Parasitemia/veterinária , Animais , DNA de Protozoário/análise , DNA de Protozoário/isolamento & purificação , Doenças do Cão/parasitologia , Cães , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Hibridização de Ácido Nucleico , Parasitemia/diagnóstico , Parasitemia/parasitologia , Peru , Reação em Cadeia da Polimerase/métodos , Sensibilidade e EspecificidadeRESUMO
This paper reviews the current knowledge of leishmaniasis epidemiology in Venezuela, Colombia, Ecuador, Peru, and Bolivia. In all 5 countries leishmaniasis is endemic in both the Andean highlands and the Amazon basin. The sandfly vectors belong to subgenera Helcocyrtomyia, Nyssomiya, Lutzomyia, and Psychodopygus, and the Verrucarum group. Most human infections are caused by Leishmania in the Viannia subgenus. Human Leishmania infections cause cutaneous lesions, with a minority of L. (Viannia) infections leading to mucocutaneous leishmaniasis. Visceral leishmaniasis and diffuse cutaneous leishmaniasis are both rare. In each country a significant proportion of Leishmania transmission is in or around houses, often close to coffee or cacao plantations. Reservoir hosts for domestic transmission cycles are uncertain. The paper first addresses the burden of disease caused by leishmaniasis, focusing on both incidence rates and on the variability in symptoms. Such information should provide a rational basis for prioritizing control resources, and for selecting therapy regimes. Secondly, we describe the variation in transmission ecology, outlining those variables which might affect the prevention strategies. Finally, we look at the current control strategies and review the recent studies on control.
Assuntos
Leishmaniose/epidemiologia , Animais , Bolívia/epidemiologia , Colômbia/epidemiologia , Equador/epidemiologia , Humanos , Incidência , Insetos Vetores , Leishmania/classificação , Leishmania/fisiologia , Leishmaniose/diagnóstico , Leishmaniose/terapia , Peru/epidemiologia , Fatores de Risco , VenezuelaRESUMO
Originally associated with forested areas, the transmission cycle of American cutaneous leishmaniasis (ACL) has now adapted to the domestic environment in at least 9 Latin American countries. Several studies have suggested that the domestic dog (Canis familiaris), which is already incriminated as the primary reservoir host of zoonotic visceral leishmaniasis (ZVL), may have a reservoir role in the domestic transmission of human ACL caused by Leishmania braziliensis, L. panamensis, and L. peruviana. This article reviews more than 90 studies reporting ACL infections in dogs, and concludes that as yet there is only circumstantial evidence to support that claim. Almost no data are available on the infectiousness of dogs to sandfly vectors of ACL, and there are few indications that either dog ownership or dog abundance are risk factors for ACL. Nevertheless, it has been proposed that incidence of ACL in humans could be reduced by targeting infected dogs. While this control strategy has been used for many decades against ZVL in Latin America, Europe, and Asia, there is little evidence to demonstrate its effectiveness either in theory or in practice. Particular concerns over the sensitivity and specificity of diagnostic tools, low compliance rates among dog owners, and cost-effectiveness are likely to apply equally to ACL control.
Assuntos
Reservatórios de Doenças , Doenças do Cão/epidemiologia , Leishmania braziliensis/patogenicidade , Leishmaniose Cutânea/epidemiologia , Animais , Animais Domésticos , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Comportamento Alimentar , Humanos , Incidência , Mordeduras e Picadas de Insetos/epidemiologia , Mordeduras e Picadas de Insetos/veterinária , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Leishmaniose Cutânea/transmissão , Psychodidae/parasitologia , Psychodidae/fisiologia , Saúde Pública , Fatores de Risco , América do Sul/epidemiologia , Estados Unidos/epidemiologia , Zoonoses/epidemiologia , Zoonoses/transmissãoRESUMO
Evidence that domestic dogs may act as reservoir hosts for cutaneous leishmaniasis in the Peruvian Andes is provided by the isolation, for the first time, from naturally infected dogs of parasites identified (by isoenzymes) as Leishmania peruviana. Leishmania parasites were isolated from nasal aspirates or biopsies from 5 (1.8%) of 279 asymptomatic dogs samples in endemic villages of the Peruvian Andes. In addition, Leishmania (Viannia) infections were identified in 15 (5.4%) of 276 nasal samples by the polymerase chain reaction (PCR) using subgenus-specific primers. Further circumstantial evidence for a reservoir role for dogs comes from the finding of a relatively high dog blood index among the sandfly vectors collected inside houses (29% for Lutzomyia peruensis and 17% for Lu. verrucarum). Possible wild mammal reservoir hosts for Andean cutaneous leishmaniasis were also detected in endemic villages. At least 8 species were identified among the 1266 small mammals trapped. Leishmania parasites were isolated from blood or skin biopsies taken from 2 (2.6%) of 78 Didelphis albiventris and 6 (1.2%) of 511 Phyllotis andinum. Three isolates were identified by isoenzymes as L. peruviana, and the other 5 were identified by PCR as Leishmania (Viannia) species. Leishmania (Viannia) infections were also identified by PCR directly on skin biopsies taken from 2 (2.8%) of 72 D. albiventris, 1 (0.2%) of 499 P. andinum, and 4 (2.6%) of 153 Akodon sp.
Assuntos
Vetores de Doenças , Doenças do Cão/parasitologia , Leishmaniose Cutânea/veterinária , Animais , Animais Domésticos/parasitologia , Antígenos/análise , Doenças do Cão/epidemiologia , Cães , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Peru/epidemiologia , Psychodidae/imunologiaRESUMO
Phylogenetic analysis of all 31 described mitochondrial (cytochrome b) haplotypes of Lutzomyia whitmani demonstrated that new material from the State of Rondônia, in southwest Amazônia, forms a clade within a lineage found only in the rain-forest regions of Brazil. This rain-forest lineage also contains two other clades of haplotypes, one from eastern Amazônia and one from the Atlantic forest zone of northeast Brazil (including the type locality of the species in Ilhéus, State of Bahia). These findings do not favour recognizing two allopatric cryptic species of L. whitmani, one associated with the silvatic transmission of Leishmania shawi in southeast Amazônia and the other with the peridomestic transmission of Le. braziliensis in northeast Brazil. Instead, they suggest that there is (or has been in the recent past) a continuum of inter-breeding populations of L. whitmani in the rain-forest regions of Brazil.
Assuntos
DNA Mitocondrial/genética , Psychodidae/genética , Animais , Brasil , Grupo dos Citocromos b/análise , Feminino , Humanos , Leishmaniose/transmissão , Masculino , Filogenia , Reação em Cadeia da Polimerase , Psychodidae/classificação , Análise de Sequência de DNA , Especificidade da Espécie , ÁrvoresRESUMO
Phylogenetic analysis of all 31 described mitochondrial (cytochrome b) haplotypes of Lutzomyia whitmani demostrated that new material from the State of Rondônia, in southwest Amazônia, forms a clade within a lineage found only in the rain-forest regions of Brazil. This rain-forest lineage also contains two other clades of haplotypes, one from eastern Amazônia and one from the Atlantic forest zone of northeast Brazil (including the type locality of the species in Ilhéus, State of Bahia). These findings do not favour recognizing two allopatric cryptic species of L. whitmani, one associated with the silvatic transmission of Leishmania shawi in southeast Amazônia and the other with the peridomestic transmission of Le. braziliensis in northeast Brazil. Instead, they suggest that there is (or has been in the recent past a continuum of inter-breeding populations of L. whitmani in the rain-forest regions of Brazil.