Incidence Of Human Visceral Leishmaniasis Research Articles

Challenges of animals shelters in caring for dogs infected with Leishmania and other pathogens

The incidence of human Visceral Leishmaniasis (VL) has decreased in Brazil; however, the number of areas reporting human and canine cases has increased, with Leishmania infantum usually preceding human infection. This study aimed to analyze the profile of infectious diseases that are endemic for both human and canine VL, in dogs housed in a shelter located in the state of Rio Grande do Norte, Northeast Brazil. Data was obtained between November/2021 to April/2022. All dogs residing at the shelter (98 dogs) were examined and blood was collected for testing for L. infantum, Ehrlichia canis, and Babesia sp. Statistical analyses considered the clinical and laboratory findings. Of the 98 animals, approximately 43% were positive for L. infantum antibodies, 19% were positive for L. infantum kDNA, and 18% were L. infantum positive by culture. Greater levels of anti-leishmania antibodies were observed in dogs with symptoms suggestive of VL. The dogs tested positive for E. canis (19/98) and B. canis (18/98). Lutzomyia longipalpis was captured inside the shelter, representing 74.25% (n = 225) of whole sandflies in the dog shelter. Concomitant infection by L. infantum and E. canis increased the odds of death. Treatment of VL included the use of allopurinol (n = 48) and miltefosine (n = 8). Treated animals showed more signs of Leishmania infection. Tickborn parasites and Leishmania were prevalent in sheltered dogs in a VL-endemic area, which increases the odds of death and poses an additional challenge for caring for abandoned dogs and at the same time setting protocols to manage reservoirs of L. infantum.

Impact of 4% Deltamethrin-Impregnated Dog Collars on the Incidence of Human Visceral Leishmaniasis: A Community Intervention Trial in Brazil.

In Brazil, human visceral leishmaniasis (HVL) is caused by the protozoan parasite Leishmania infantum, primarily transmitted by the sand fly Lutzomyia longipalpis, with dogs acting as the main urban reservoir. This study aims to evaluate the effectiveness of 4% deltamethrin-impregnated dog collars (DMC) on HVL incidence. This is a community intervention study carried out from 2012 to 2015 in the municipalities of Araguaína, State of Tocantins, and Montes Claros, State of Minas Gerais, Brazil. Two areas in each were randomly allocated to either (1) culling seropositive dogs + residual insecticide spraying (control area-CA) or (2) culling seropositive dogs + residual insecticide spraying + DMC fitted to dogs every six months for two years (intervention area-IA). Cases of HVL (n = 1202) occurring from 2008 to 2020 were identified from the Brazilian Reportable Diseases Information System and georeferenced to the control and intervention areas. The HVL cases from 2008 to 2012 were considered as occurring in the "pre-intervention" period. Those cases from 2013 to 2016 and from 2017 to 2020 were regarded as occurring in the "intervention" and "post-intervention" periods, respectively. We used a mixed-effects Poisson regression model to estimate the effectiveness of the intervention, comparing the changes from the pre-intervention period to the intervention and post-intervention periods in the control and intervention areas. In Araguaína, there was a statistically significant reduction in the incidence of HVL in both the control and intervention areas, comparing both the intervention and post-intervention periods with the pre-intervention period. The intervention with DMC was significantly associated with a reduction in HVL when comparing the intervention and pre-intervention periods, yielding an effectiveness estimate of the DMC of 27% (IC95% 1-46%, p = 0.045). No differences were observed when comparing the pre- and post-intervention periods (p = 0.827). In Montes Claros, cases reduced in both the control and intervention areas from the pre-intervention period to the intervention period (p = 0.913). In the post-intervention period, the incidence increased in the control area, while cases continued to decrease in the DMC area (p = 0.188). The use of DMC was associated with a reduction of 27% in the incidence of HVL during the period of DMC delivery, indicating that DMC is effective as an additional strategy for controlling visceral leishmaniasis in Brazil. However, no significant reduction associated with DMC was detected after the intervention period, suggesting that a control program based on the large-scale deployment of DMC might have to be maintained for more extended periods without interruption.

Temporal trend in the incidence of human visceral leishmaniasis in Brazil.

It is an ecological study that analyzed the time trend of visceral leishmaniasis incidence rates in Brazil using segmented time regression by joinpoints. There was a decreasing incidence rate of this disease in the country with an average annual percent change (AAPC) of -5 (CI95%: -9.1; -0.6) and a reduction of 1.69 cases/100 thousand inhabitants in 2007, and 0.91/100 thousand inhabitants in 2020. The Central-West region showed the highest reduction percent (AAPC: -9.1; CI95%: -13.8; -4.3), followed by the Southeast region (AAPC: -8.7; -14.6; -2.5). The North and South regions showed the largest number of joinpoints in the time series. The highest incidences were recorded in the male population, however, stable (AAPC: 2.14; CI95%: -8.3; 0). In the age group analysis, the trend was decreasing for the groups from 0 to 4 years old (AAPC: -7.7; CI95%: -12.6; -2.4), 5 to 9 years old (AAPC: -7.3; CI95%: -13.6; -0,4) and 10 to 14 years old (AAPC: -5.5; CI95%: -10.3; -0.3). It was found that although Visceral Leishmaniasis is an endemic disease in Brazil, there was a decrease in its incidence rate from 2007 to 2020.

The current epidemiology of leishmaniasis in Turkey, Azerbaijan and Georgia and implications for disease emergence in European countries

Leishmania spp. are sand fly‐borne protozoan parasites causing leishmaniasis in humans and animals. The aim of the study was to analyse the epidemiology of leishmaniasis in Turkey, Azerbaijan and Georgia from 2005 to 2020 and evaluate the associated risk for disease emergence in European countries. It is based on an analysis of WHO and OIE reported cases between 2005 and 2020, a review of scientific articles published in SCOPUS between 2009 and 2020 and a questionnaire survey to public health and veterinary authorities in these countries. Endemic Leishmania spp. include L. infantum in the three countries, L. major in Azerbaijan and Turkey and L. tropica and L. donovani in Turkey. Leishmaniasis is reported in humans, animals and sand flies and incidence is spatially and temporarily variable. In the southern Caucasus and particularly in Georgia, reported incidence of human visceral leishmaniasis by L. infantum remains high. However, whilst Georgia experienced a gradual decrease from >4.0 cases per 100,000 population in 2005–09 to 1.13 cases per 100,000 population in 2020, the period with highest incidence in Azerbaijan, which ranged between 0.40 and 0.61 cases per 100,000 population, was 2016–2019, and no cases have so far been reported for 2020. Visceral leishmaniasis in the Southern Caucasus affects mostly young children from deprived urban areas and its closely associated to canine leishmaniasis. Turkey reported cases of visceral leishmaniasis between 2005 and 2012 and in 2016 only, and incidence ranged between 0.02 and 0.05 per 100,000 population. In contrast, the reported annual incidence of cutaneous leishmaniasis in Turkey was much greater and peaked at 7.02 cases per 100,000 population in 2013, associated to imported cases from cutaneous leishmaniasis endemic Syria. Leishmaniasis by L. infantum in Azerbaijan and Georgia represents a regional public and animal health challenge that requires support to improve diagnosis, treatment and control. The unprecedented rise of cutaneous leishmaniasis and the spread of L. tropica and L. donovani in Turkey is an important risk factor for their emergence in Europe, especially in Mediterranean countries where competent vectors are widespread.

Human visceral leishmaniasis in Central-Western Brazil: Spatial patterns and its correlation with socioeconomic aspects, environmental indices and canine infection

In this ecological study, we investigated spatial patterns of human visceral leishmaniasis (VL) incidence, its correlation with socioeconomic aspects, environmental indices (obtained through remote sensing) and canine VL during 2011–2016 in the municipality of Rondonópolis, a relevant endemic area for VL in Central-Western Brazil. Human VL cases were georeferenced and point patterns were analyzed by univariate Ripley's K function and Kernel density estimation (KDE). Poisson-based scan statistics were used to investigate spatial and spatiotemporal clusters of human VL incidence at the neighborhood level. Socioeconomic and environmental characteristics were compared between neighborhoods within and outside spatial human VL clusters. Also, we assessed the correlation between smoothed human VL incidence and canine VL seropositivity rates within and between neighborhoods. Human VL cases were clustered up to 2000 m; four hotspots were identified by KDE in peripheral areas. Spatial and spatiotemporal low-risk clusters for human VL were identified in central and southern areas. Neighborhoods within spatial low-risk cluster presented higher mean income, literacy rate, sanitary sewage service coverage and lower altitude, compared to the rest of the municipality. A positive correlation was found between the occurrence of human and canine VL. On the northern outskirts, high human VL incidence was spatially correlated with high canine VL seropositivity in surrounding neighborhoods. In conclusion, human VL demonstrated a heterogeneous, aggregated and peripheral spatial pattern. This distribution was correlated with intra-urban socioeconomic differences and canine VL seropositivity at the neighborhood level.

Incidence of human visceral leishmaniasis: the importance of municipal socio-economic indicators in the state of Pernambuco, Brazil

Objective: To analyze the main municipal socioeconomic factors associated with the incidence of HVL in the state of Pernambuco, northeastern Brazil. Methods: It is a analytical cross-sectional study. Data on the incidence of HVL and socioeconomic factors were collected from 954 cases notified by the SINAN (National System of Notifiable Diseases) and SIM (Mortality Information System). The cases considered were reported by municipalities in the state of Pernambuco, Brazil, from 2005 to 2014. Statistical differences were analyzed by Pearson's correlation test, followed by multiple regression analysis. Significant differences were considered when p <0.05. Results: The FIRJAN Municipal Development Index was the variable that showed the most remarkable statistical robustness and strong negative association with the incidence of HVL. The municipal spending on health and residing in the metropolitan region also influenced its mean incidence rates. Conclusion: The indicators that had an influence on the performance of the incidence of LVH were the FIRJAN Municipal Development Index, health expenditure and residing in the metropolitan region.

Effects of El Niño-Southern Oscillation on human visceral leishmaniasis in the Brazilian State of Mato Grosso do Sul.

BACKGROUND Leishmaniases are considered a major public health problem in South America, specifically in Brazil. Moreover, the transmission and epidemiology of leishmaniasis are possibly associated with climatic and environmental variations.OBJECTIVE This study aimed to assess the association between the extreme climatic phenomenon El Niño-Southern Oscillation (ENSO), the maximum and minimum variations of temperature, precipitation, and soil moisture and the incidence of visceral leishmaniasis (VL) in Mato Grosso do Sul (MS), Brazil, from 2002 to 2015.METHODS The Niño 3.4 index was used for the ENSO variation. The other climatic data were obtained from the climatic tool TerraClimate. Records regarding VL were obtained from the Notification of Injury Information System.FINDINGS From 2002 to 2015, there were 3,137 cases of VL recorded in MS. The annual incidence of the disease was negatively associated with the ENSO index and soil moisture in MS. The VL incidence increased during the negative phase of ENSO and decreased during the positive phase.MAIN CONCLUSIONS The results demonstrated that the interannual cycles of incidence of human VL are significantly associated with the occurrence of the ENSO phenomenon and its phases, El Niño and La Niña.

Failure of the dog culling strategy in controlling human visceral leishmaniasis in Brazil: A screening coverage issue?

In the present study, we assessed the annual screening coverage (i.e., the percentage of dogs that are screened for anti-Leishmania antibodies annually) in the municipality of Sobral, Ceará state, Brazil. Data on the number of dogs screened during 2008−2017 (except 2010) were obtained from the Centre for Zoonoses Control of Sobral. The annual screening coverage during 2012−2017 was calculated. Data on human visceral leishmaniasis (VL) cases during 2008−2017 were compiled from the National Disease Notification System. Correlation analyses were performed to assess the correlation between canine and human data. During 2008−2017, 73,964 dogs (range, 0 to 13,980 dogs/year) were serologically screened and 2,833 (3.8%) were positive. The annual screening coverage during 2012−2017 ranged from 11.1% to 45.7%. There were no significant correlations between the number of dogs culled and the number of human VL cases, canine positivity and human VL incidence, number of dogs culled and human VL incidence, or between canine positivity and number of human VL cases. An inconsistent and relatively low annual screening coverage was found in the study area, with no dog being screened in 2010 due to the lack of serological tests. Our results highlight that many dogs potentially infected with Leishmania infantum have been virtually overlooked by public health workers in the study area, perhaps with a negative, yet underestimated, impact on the control of canine and human VL. Hence, the failure of the dog culling strategy in controlling human VL in Brazil may be due to the low screening coverage and low percentage of culled dogs, rather than the absence of associations between canine and human infections.

Space-time analysis of the incidence of human visceral leishmaniasis (VL) and prevalence of canine VL in a municipality of southeastern Brazil: Identification of priority areas for surveillance and control

Human and canine visceral leishmaniasis (HVL and CVL, respectively) represent serious public health issues in Brazil. The surveillance and control measures currently employed have had limited effect in impeding the territorial expansion of the disease and in reducing the number of cases. We have investigated the space-time distribution of HVL incidence rates and CVL prevalence in the coverage areas of the 148 primary healthcare units in Belo Horizonte (MG, Brazil) during a 6-year period in order to identify those that should be prioritized for disease control actions. Data were smoothed using the empirical Bayes method and analyzed by space-time scanning and application of univariate global Moran’s I index and local indicators of spatial association (LISA) statistics to identify spatial autocorrelations. Point data of CVL were analyzed using the Kernel method. Bivariate global Moran’s I and LISA techniques were employed to identify spatial correlations between HVL and CVL. Based on our results, we were able to formulate two proposals for establishing the prioritization of coverage areas, namely: (i) classification of maximum priority areas as identified by bivariate LISA for HVL and CVL, and (ii) combination of maximum priority areas with high priority areas as identified by univariate LISA for HVL. According to our proposals, 27 coverage areas in Belo Horizonte were categorized as maximum priority and a further 13 were classified as high priority. Our proposals, which are based on practical, feasible and inexpensive statistical tools, will contribute to a better understanding of VL distribution in urban settings and improving the efficiency of governmental control programs.

Acute visceral leishmaniasis in a domestic cat (Felis silvestris catus) from the state of Tocantins, Brazil

Visceral leishmaniasis (VL) is expanding in the Brazilian territory. Dogs are considered an important urban reservoir; however, studies have demonstrated the presence of infected cats in some Brazilian states. This report aimed to describe a case of Leishmania (Leishmania) infantum infection in a two-month-old domestic feline from a Brazilian region with a high incidence of human visceral leishmaniasis. The analyzed samples were the cat’s blood, conjunctiva, spleen, liver, popliteal, submandibular and mesenteric lymph nodes, skin, lung and kidney. The diagnostic methods were: parasitological examination, polymerase chain reaction (PCR) and an immunoflurescence antibody test (IFAT). All tissues were positive. The title obtained using the IFAT was 1:160. The animal was negative for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). This work addresses the first case of feline leishmaniasis in the state of Tocantins, and reveals data that may contribute to the knowledge of the disease, since it has been shown to be able to develop rapidly and fatally in kittens, with the ability to infect several tissues.

Human visceral leishmaniasis and relationship with vector and canine control measures.

ABSTRACTOBJECTIVE Estimate the coverage of control measures of visceral leishmaniasis and relate them with the occurrence of human visceral leishmaniasis in endemic urban area.METHODS Cases of human and canine visceral leishmaniasis were considered as study population and evaluated by a serological survey conducted in Araçatuba, state São Paulo, from 2007 to 2015. The cases of human visceral leishmaniasis were geocoded by the address of the patients and the canine disease by the address of the dogs’ owners. The coverage of serological survey, euthanasia, and insecticide spraying was calculated, as well as the canine seroprevalence and the incidence rates of human visceral leishmaniasis. The relationship between human visceral leishmaniasis and control measures was evaluated, as well as the seroprevalence by comparing maps and by linear regression. The relationship between the canine and the human disease was also evaluated by the Ripley’s K function.RESULTS The incidence rates of human visceral leishmaniasis showed a period of decline (2007 to 2009) and a period of stability (2010 to 2015), a behavior similar to that of canine seroprevalence. In general, the coverage of control measures was low, and the non-association with the incidence of human visceral leishmaniasis can be a result of the period analyzed and of the small number of analyzed units (sectors of the Superintendence for the Control of Endemic Diseases). The distribution of human cases showed spatial dependence with the distribution of seropositive dogs from 2007 to 2009.CONCLUSIONS This study reaffirmed the relationship between the occurrence of the disease in humans and dogs, it verified a decrease in the rates of visceral leishmaniasis in Araçatuba over time, even at low coverage of control activities. However, further studies are needed to determine if factors beyond monitoring and control measures are involved in the reduction of incidences.

Impact of 4% deltamethrin-impregnated dog collars on the incidence of human visceral leishmaniasis

Impact of 4% deltamethrin-impregnated dog collars on the incidence of human visceral leishmaniasis

Epidemiological aspects of human and canine visceral leishmaniasis in State of Alagoas, Northeast, Brazil.

Our data are important because canine infection is an important risk factor for the human disease.

Changing epidemiology of visceral leishmaniasis in northeastern Brazil: a 25-year follow-up of an urban outbreak.

Visceral leishmaniasis (VL) continues to be a deadly parasitic disease in Brazil but the epidemiology has changed. The objective of this study was to assess the evolution of urban VL in the city of Natal, Brazil, over the past 25 y. A retrospective study of human VL was performed, considering reported cases over the past 25 y in Natal. Analyses considered the spatial distribution of VL cases, human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) co-infection, Leishmania infantum infection in dogs, density of the insect vector (Lutzomyia longipalpis) and socio-economic factors. Paralleling migration of the population, VL cases changed from mostly rural to predominantly urban regions. The incidence of human VL was highest during the initial years (1990-1994) of our study. Human VL was positively associated with a high density of L. longipalpis, a high prevalence of canine L. infantum infection and HIV/AIDS co-infection. The average age at diagnosis increased over prior years and males were more frequently affected. The overall fatality rate was 6%. Socio-economic variables indicative of poverty were associated with a greater incidence of VL and clusters of VL. VL has become endemic in Natal. The disease is associated with poverty and male gender. Surprisingly, there has been an increase in the age at diagnosis.

Vulnerability to the transmission of human visceral leishmaniasis in a Brazilian urban area.

ABSTRACTOBJECTIVE To analyze the determinants for the occurrence of human visceral leishmaniasis linked to the conditions of vulnerability.METHODS This is an ecological study, whose spatial analysis unit was the Territorial Analysis Unit in Araguaína, State of Tocantins, Brazil, from 2007 to 2012. We have carried out an analysis of the sociodemographic and urban infrastructure situation of the municipality. Normalized primary indicators were calculated and used to construct the indicators of vulnerability of the social structure, household structure, and urban infrastructure. From them, we have composed a vulnerability index. Kernel density estimation was used to evaluate the density of cases of human visceral leishmaniasis, based on the coordinates of the cases. Bivariate global Moran’s I was used to verify the existence of spatial autocorrelation between the incidence of human visceral leishmaniasis and the indicators and index of vulnerability. Bivariate local Moran’s I was used to identify spatial clusters.RESULTS We have observed a pattern of centrifugal spread of human visceral leishmaniasis in the municipality, where outbreaks of the disease have progressively reached central and peri-urban areas. There has been no correlation between higher incidences of human visceral leishmaniasis and worse living conditions. Statistically significant clusters have been observed between the incidences of human visceral leishmaniasis in both periods analyzed (2007 to 2009 and 2010 to 2012) and the indicators and index of vulnerability.CONCLUSIONS The environment in circumscribed areas helps as protection factor or increases the local vulnerability to the occurrence of human visceral leishmaniasis. The use of methodology that analyzes the conditions of life of the population and the spatial distribution of human visceral leishmaniasis is essential to identify the most vulnerable areas to the spread/maintenance of the disease.

Occurrence of Lutzomyia longipalpis andhuman and canine cases of visceral leishmaniasis and evaluation of their expansion in the Northwest region of the State of São Paulo, Brazil.

INTRODUCTION This paper aims to describe the dispersion of Lutzomyia longipalpis and the autochthonous occurrence of visceral leishmaniasis (VL) in the Northwest region of the State of São Paulo between 2007 and 2013 and to analyze their expansion. METHODS Information about the vector and associated cases was described using maps. The incidence, mortality, and lethality of human visceral leishmaniasis (HVL) were calculated. In municipalities in which more than one HVL case occurred, incidences were calculated according to census sector, and spatial and spatiotemporal clusters were identified. RESULTS The first case of HVL was reported in the municipality of Jales in 2007. By 2013, the vector and the disease had expanded from west to east, with the vector being detected in 29 municipalities. A total of 11 municipalities had cases of canine visceral leishmaniasis (CVL), and six had cases of HVL. Vector expansion occurred by vicinity with previously infested municipalities, and the expansion of VL was related to the major highways and the capital municipalities of the micro-regions in the study area. The highest incidence of HVL occurred in children between 0-4 years old, and the highest mortality and lethality occurred among persons aged 60 and older. The occurrence of HLV was more intense in the peripheral areas of municipalities with the disease. CONCLUSIONS The findings of this study may be useful for improving VL surveillance and control activities by slowing VL expansion and/or mitigating VL effects when they occur.

Spatial analysis for identification of priority areas for surveillance and control in a visceral leishmaniasis endemic area in Brazil

Spatial analysis of epidemiological data may be used to assist in the implementation of surveillance and control measures against visceral leishmaniasis (VL) in endemic areas. This ecological study aimed to identify priority areas for surveillance and control of VL in São Luís, the capital of the state of Maranhão in northeast Brazil, a highly endemic area for the disease. We evaluated the spatial structure of the incidence rates of human VL and of the mean number of human and canine cases occurring between 2005 and 2007 in 355 neighborhoods (aggregated into 203 geographical analytical units) within the municipality. The presence of spatial autocorrelation was explored using global and local Moran's I statistics. A local indicator of spatial autocorrelation was used to generate maps for the identification of VL clusters. The global Moran's I index revealed a weak, but statistically significant spatial autocorrelation for human VL incidence rates (I=0.138). A total of 43 geographical analytical units, encompassing 121 neighborhoods, were identified as priority areas for implementing surveillance and control actions. For the purpose of defining an action plan for the delivery of these measures, those 16 geographical analytical units (encompassing 54 neighborhoods) identified as clusters with high incidence rates of human VL should receive the highest priority. An additional nine geographical analytical units (comprising 28 neighborhoods) showed non-significant clustering of high rates of human, and might be considered as the next priority for VL management. Finally, a further 18 geographical analytical units (covering 39 neighborhoods) had records of coexisting human and canine VL cases during the study period, and these should receive priority attention when resources become available. Spatial data analysis is a valuable tool for defining priority areas for VL surveillance in high transmission areas contributing to a more effective management of financial and technical resources, increasing the sustainability and efficiency of control efforts.

Transmission of visceral leishmaniasis in a previously non-endemic region of Tunisia: Detection ofLeishmaniaDNA inPhlebotomus perniciosus

Visceral leishmaniasis (VL) has been endemic in northern Tunisia and has occurred sporadically in the center of Tunisia. Recently, there have been several cases from areas known to be free of VL. We report in this work all human and canine cases of VL recorded between 2003 and 2011 and an entomological study of phlebotomine fauna in a previously non-endemic region. Sixty-three cases of VL were diagnosed and identified as L. infantum using several different methods. Eight species of 179 sand flies were caught and identified by both morphological and molecular methods. Two genera were present, Phlebotomus and Sergentomya, with an abundance of the subgenus Phlebotomus (Larrousius) spp., a classic vector of VL in Tunisia. Moreover, Leishmania DNA was detected in seven unfed Phlebotomus pernicousus and L. infantum was identified in three of them. This result confirms the establishment of a transmission cycle of VL in the studied region by the coexistence of infected vectors with infected hosts.

Asymptomatic domestic dogs are carriers of Leishmania infantum: possible reservoirs host for human visceral leishmaniasis in southern Iran

In the past few years, the incidence of human visceral leishmaniasis (HVL) has increased in many districts of Fars Province, southwest of Iran, particularly, among communities of nomadic tribes. Recent epidemiological reports in Leishmania infantum endemic regions of Iran indicate that more than 50–70% of seropositive dogs are asymptomatic for Leishmania infection. Between 2004 and 2006, blood samples were collected from 110 domestic dogs from nomadic and rural areas. Each of these samples was tested for anti-Leishmania antibodies, in direct agglutination tests (DATs), and for L. infantum kinetoplast deoxyribonucleic acid (kDNA), in polymerase chain reaction (PCR)-based assays. Of the 110 dogs, 5.5% (6/110) were found seropositive and 23% (25/110) PCR-positive. Four of the six seropositive (67%) and 22 of the 25 PCR-positive (88%) were asymptomatic. The rate of infection in dogs from nomadic communities was higher (27%) than dogs from rural areas (18%). Since positivity in the PCR-based assay indicated the presence of L. infantum amastigotes in the peripheral blood of 23% of the subjects, it is clear that these asymptomatic dogs (88%) are quite common in the study areas and probably act as reservoirs in the transmission of Leishmania parasites, to humans and to other dogs, by sandflies. Moreover, our study showed that application of PCR to buffy coat samples gave a better estimate of the real rate of infection in asymptomatic dogs than DAT.

Phlebotominae fauna (Diptera: Psychodidae) in an urban district of Belo Horizonte, Brazil, endemic for visceral leishmaniasis: Characterization of favored locations as determined by spatial analysis

Belo Horizonte, the capital of the southeastern state of Minas Gerais, Brazil, and the fourth-largest city in the country, has the highest incidence of human visceral leishmaniasis (VL) together with a high prevalence of canine VL. The Northeast Sanitary District (NSD) of Belo Horizonte has the largest historical average of human VL cases in the metropolitan region, and is classified as a priority area for epidemiological and entomological monitoring of the disease. The objectives of the present study were to determine the seasonal variation in phlebotomine fauna and to describe the environmental situations in the NSD through characterization of peri-domiciles and application of geographical information system analysis. Entomological captures were performed every two weeks during the period July 2006 to June 2007 using HP light traps placed at 16 locations where cases of human VL had been reported in 2005. The environmental characterization of these locations was accomplished using forms and photographic images. Spatial analyses was used to determine the influence of vegetation, hydrography, altitude and pockets of poverty on the occurrence of cases of human and canine VL, and of phlebotomine vectors. A total of 633 phlebotomines belonging to the subtribes Psychodopygina and Lutzomyina were captured and, of these, 75% were identified as Nyssomyia whitmani and 11% as Lutzomyia longipalpis. The majority of the studied peri-domiciles presented inadequate hygienic conditions that would favor the development of phlebotomines. No significant correlations could be established between biogeographical aspects and either the incidence of human and canine VL or the occurrence of phlebotomines. The proximity of areas with vegetation, villages, slums and open watercourses exerted little influence on the incidence of VL. These findings reinforce the urbanization of the VL profile since the disease occurred in locations where conditions that have been classically related to its prevalence were not present. The results reported herein will be important for implementing measures against VL in the study area.