Canine visceral leishmaniasis: seroprevalence and risk factors in Cuiabá, Mato Grosso, Brazil

Patterns and drivers of Human Visceral Leishmaniasis in Pernambuco (Brazil) from 2007 to 2018

Visceral leishmaniasis (VL) is the second most common protozoosis that affects people around the world. The aim of this study is to understand how environmental and socioeconomic factors, as well as VL control and surveillance interventions, influence the spread and detection of VL cases in Pernambuco state (Brazil). A novel model was developed to analyze cases of VL between 2007 and 2018, enabling the quantification of the association of these variables with two processes: the probability of "invasion" (emergence of new cases) at municipalities by VL, and the probability of detecting cases not reported in municipalities that have already been invaded. Pernambuco state identified 1,410 cases of VL between 2007 and 2018, with an average of 128 cases per year and average incidence of 1.28/100 thousand people. These cases were distributed in 77.1% (142/184) of the municipalities, and 54.8% (773/1,410) of them were autochthonous. Our model reveals that the proportion of agriculture was positively associated with VL invasion probability. We also find that municipalities that are closer to notification centers and/or that have received technical training and support tend to have higher detection rates of VL cases. Taken together, these results suggest that a municipality with almost no agriculture and that received technical training, located close to a notification center, is unlikely to be invaded if no cases have ever been detected. On the other hand, a municipality that is far from the notification center, with no technical training, with a large agricultural area might have already been invaded but the surveillance system might have routinely failed to detect VL cases due to low detection probability. By disentangling the processes of invasion and detection, we were able to generate insights that are likely to be useful for the strategic allocation of VL prevention and control interventions.

Factors associated with the expansion of leishmaniasis in urban areas: a systematic and bibliometric review (1959-2021)

This work describes a systematic and bibliometric review of the factors that contribute to the expansion of leishmaniasis in urban areas. Three scientific databases were used: Scientific Electronic Library (SciELO), Scopus and Web of Science, encompassing all original and review articles between 1959 and 2021. Three descriptors were used: "leishmaniasis" AND "urban" AND "rural." Planning, execution, summarization, and selection processes were performed using StArt (State of the Art through Systematic Review) software. We obtained a total of 304 articles, 60 of which concerned canine leishmaniasis. The factors associated with the expansion of leishmaniasis in urban areas are interrelated, including socioenvironmental and economic complexity, the type of leishmaniasis, the reservoirs, vectors, deforestation, disorderly occupation of space, poor sanitary conditions, and human migration trends. A lack of diagnosis and underreporting of cases in some regions may reflect the increase of cases seen in urban areas. A majority (n = 121) of studies were conducted in Brazil, followed by Iran (n = 43). In relation to publications; in general, output has increased over the years, particularly in 2021. The majority of published studies were in the area of epidemiology (n = 158).

Canine leishmaniasis in an endemic region, Northeastern Brazil: a comparative study with four groups of animals

Canine leishmaniasis (CanL) is a zoonosis caused by protozoa of the genus Leishmania and remains an important public health concern in tropical areas. In Brazil, domestic dogs are considered the most relevant reservoir of the parasite and one of the main targets of the disease control actions. Considering this, we aimed herein to evaluate the CanL infection in different canine groups and distribution of cases in the state of Sergipe, an endemic region in Northeastern Brazil. The evaluated 467 animals were classified into four groups: hunting (n = 50), company (n = 64), guard (n = 140), and wandering (n = 213). Samples (blood, bone marrow, conjunctival swab, and lymph node aspirate) were collected from animals in nine municipalities of Sergipe. First, all animals were submitted to general and ophthalmic clinical examination. Next, they were tested serologically by TR-DPP®, and for the presence of Leishmania, amastigotes in samples of bone marrow, conjunctival swab, and lymph node aspirate were diagnosed by PCR and parasitological techniques. It was observed that 34.69% (162) of the evaluated dogs were seropositive. The highest rates of positivity were found in hunting 54% (27/50; OR = 3.52; p-value = 0.001) and guard dogs 42.14% (59/140; OR = 2.18; p-value = 0.01). Otherwise, the highest percentage of symptomatic dogs was observed in wandering animals (85%; OR = 9.63; p-value < 0.0001). The distribution of case analysis showed that the highest positivity rates occurred in inland municipalities situated in arid regions. Taken together, our data demonstrate that hunting and guard dogs are among the animals most exposed and affected by clinical manifestations of CanL, mainly in the inland municipalities of Sergipe State.

Características clínico-epidemiológicas de leishmaniasis visceral canina en un área endémica de Paraguay

Objetivo Describir las características clínico-epidemiológicas asociadas a la transmisión de leishmaniosis visceral canina en un área endémica del departamento de Caaguazú, Paraguay. Materiales y Métodos El estudio fue descriptivo observacional, de corte transversal. Se evaluaron 324 caninos seleccionados de 110 viviendas. Se realizó el examen clínico; se obtuvo aspirado de ganglio para el examen directo y muestra de sangre para la posterior detección de anticuerpos anti-Leishmania revelados en tiras inmunocromatográfias. Resultados El 4,9% de la población canina dio positivo con antígeno recombinante rK39. Por la técnica de tinción con Giemsa, se obtuvo 4,3% de canes positivos, de los cuales 37,5% presentaron signos clínicos evidentes. Los signos más frecuentes encontrados en los perros infectados fueron adelgazamiento, onicogrifosis y alopecia (25%). La seroprevalencia fue mayor en perros entre 2 y 4 años de raza mestiza. Conclusiones Los signos clínicos presentes confirmaron la infección parasitaria y el hallazgo indica el rol de los caninos en la epidemiologia de la leishmaniosis en Caaguazú, así como el riesgo que representan para la transmisión. Los resultados obtenidos podrían ayudar a formular un sistema de monitoreo y contribuir con la vigilancia de la leishmaniosis canina en la zona.

Differentials in the epidemiological profile of canine visceral leishmaniasis in the semi-arid region of Paraíba, Brazil

ABSTRACT: The objective of this study was to estimate the prevalence of canine visceral leishmaniasis (CVL) and to identify the differences in associated factors to its occurrence in urban area and countrysides in the municipality of Santa Luzia located in the semi-arid region of Paraíba. In the years 2015 and 2016, 779 blood samples from dogs were collected. The prevalence was determined by three serological techniques, ELISA-S7® Kit, DPP® Rapid Test and EIE-LVC® Kit, considering positive the samples that reacted in at least two assays. Associated factors were determined by univariate and multivariate analyzes of the guardians’ responses to the epidemiological questionnaire. The prevalence of anti-Leishmania infantum antibodies in the studied municipality was 15.00% (117/779), being higher in the urban area (15.20%) than in the countryside (13.60%). The neighborhood with the highest prevalence was Frei Damião with 26.40% (33/125), being considered a hotspot (OR 1.245, p=0.007). Other associated factors were the semi-domiciliary breeding (OR 1.798, p=0.025), in the urban area, and hunting dog (OR 18.505, p=0.016), contact with cattle (OR 17.298, p=0.022) and environment where the dog is raised (OR 4.802, p=0.024) in the countryside. In the municipality of Santa Luzia, the prevalence of canine visceral leishmaniasis is high and the disease is widely distributed. Epidemiological differences between urban area and the countryside could be observed demonstrating the need for more adequate control measures for each locality and proving the urbanization process.

Risk factors associated with Leishmania exposure among dogs in a rural area of Ilha Solteira, SP, Brazil

INTRODUCTION:

We sought to determine risk factors (RFs) associated with the presence of antibodies against Leishmania in dogs from a rural area of Ilha Solteira, SP, Brazil.

METHODS:

Serum samples were collected from 250 dogs and tested using indirect enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody tests (IFATs). Data concerning dogs, their environment, and their owners’ knowledge of leishmaniasis were collected using a questionnaire. To determine RFs for contact with the parasite, univariate statistical analysis based on chi-squared and Fisher’s exact tests, followed by logistic regression, was used.

RESULTS:

It was found that 79/250 (31.6%) of the dogs were positive by IFAT, and 72/250 (28.8%) by ELISA. A total of 82/250 dogs (32.8%) were positive in at least one test. The RFs associated with occurrences of Leishmania exposure were large body size (OR = 2.25; 95% CI = 1.26-4.04; p = 0.003), presence of chickens (OR = 1.94; 95% CI = 1.05-3.65; p = 0.023), and lack of knowledge about Leishmania among dog owners (OR = 1.74; 95% CI = 0.96-3.21; p = 0.049). After multivariate analysis, the RFs for occurrence of Leishmania exposure in dogs that remained significantly associated were the dog’s size (large dogs) (OR = 1.2; 95% CI = 1.06-1.35; p = 0.003) and presence of chickens on the properties (small farms) (OR = 1.15; 95% CI = 1.02-1.30; p = 0.023).

CONCLUSIONS:

These results may be useful for improving preventive practices to reduce the incidence of Leishmania exposure among dogs in rural areas.

Chronic copper poisoning in beef cattle in the state of Mato Grosso, Brazil

ABSTRACT: Copper is an essential micromineral in animal feed; however, when consumed in excess, it can cause liver necrosis, hemolytic crisis, hemoglobinuric nephrosis and death in cattle. Although uncommon in this species, copper poisoning occurs as a result of exacerbated supplementation, deficiency of antagonist microminerals, or previous liver lesions. An outbreak of chronic copper poisoning is reported in semi-confined cattle after supplementation with 50 mg/Kg of dry matter copper. The cattle showed clinical signs characterized by anorexia, motor incoordination, loss of balance, jaundice, brownish or black urine, diarrhea and death, or were found dead, 10 to 302 days after consumption. Of the 35 cattle that died, 20 underwent necropsy, whose frequent findings were jaundice, enlarged liver with evident lobular pattern, black kidneys, and urinary bladder with brownish to blackish content. Microscopically, the liver showed vacuolar degeneration and/or zonal hepatocellular centrilobular or paracentral coagulative necrosis, in addition to cholestasis, mild periacinal fibrosis, apoptotic bodies, and mild to moderate mononuclear inflammation. Degeneration and necrosis of the tubular epithelium and intratubular hemoglobin cylinders were observed in the kidneys. Copper levels in the liver and kidneys ranged from 5,901.24 to 28,373.14 μmol/kg and from 303.72 to 14,021 μmol/kg, respectively. In conclusion, copper poisoning due to excessive nutritional supplementation is an important cause of jaundice, hemoglobinuria, and death in semi-confined cattle.

Canine visceral leishmaniasis: perception, prevalence, and spatial distribution in municipality of Nossa Senhora do Livramento, Mato Grosso, Brazil

The midwest region of Brazil has witnessed an increase in the number of cases of human (HVL) and canine visceral leishmaniasis (CVL). The aim of the present study was to evaluate the population's perception of these diseases, factors associated with CVL, its spatial distribution, and the prevalence of anti-Leishmania spp. in 385 dogs, determined using a commercially available immunochromatographic rapid test and confirmed using enzyme-linked immunosorbent assay (ELISA). Of the 385 samples, 54 were positive for CVL and confirmed by ELISA, corresponding to a prevalence of 14%. Knowledge of signs of CVL by tutors (p = 0.038); previous occurrence of CVL in the vicinity (p = 0.022); symptomatic dog(s) (p = 0.014), splenomegaly (p = 0.055), and ear ulcer(s) (p = 0.059) were significantly associated with CVL. The results revealed a significant prevalence of CVL spatially distributed in rural and urban contexts. The association between environmentally related variables and perception and the occurrence of CVL underscores the importance of implementing control and prevention strategies primarily focused on environmental management and health education activities.

Epidemiological aspects of Leishmaniasis in the Pantanal region of Mato Grosso

Leishmaniasis is a disease caused by the protozoan Leishmania parasite that is disseminated by some species of sandflies and hosted by a variety of reservoirs. The objective of the present study was to evaluate the epidemiological situation of leishmaniasis in the municipalities of the Mato Grosso Pantanal. Human data were obtained from the Information System of Notifiable Diseases, and the canine and vector results from the State Department of Health of Mato Grosso. Between 2007 and 2016, 10 cases of visceral leishmaniasis and 499 cases of tegumentary leishmaniasis were identified in the Pantanal region. The surveillance studies regarding the canine reservoir demonstrated that the parasite was present in six of the seven municipalities. Vectors of visceral leishmaniasis were present in five municipalities and vectors of tegumentary leishmaniasis in six. Enhancement of services aimed at controlling this disease is fundamental to prevent an increase in the number of cases in the region.

Spatiotemporal analysis and environmental risk factors of visceral leishmaniasis in an urban setting in São Paulo State, Brazil

Background

In Latin America, Brazil harbors the most cases of human visceral leishmaniasis (HVL). Since the early 1980s, the disease has spread to the urban centers of the north, and now the south and west of Brazil; it reached São Paulo state in the southeast in 1996, and Presidente Prudente in the western region in 2010. Our aim was to describe the spatiotemporal analysis and environmental risk factors associated with the dispersion of VL in Presidente Prudente, an urban setting with recent transmission.

Methods

An entomological survey was carried out from 2009 to 2015. A canine visceral leishmaniasis (CVL) serosurvey was performed from 2010 to 2015 using enzyme-linked immunosorbent assays (ELISA), a dual-path platform CVL rapid test, and indirect fluorescent antibodies (IFAT). Data from HVL cases were obtained from the Municipal Surveillance Epidemiology Center from 2013 to 2017. Data on water drainage and forest fragments were obtained from public platforms and irregular solid-waste deposits were determined by monthly inspections of the urban area. Kernel density maps of the distribution of CVL were constructed.

Results

From 2009 to 2015, Lutzomyia longipalpis sand flies were found in all seven areas of Presidente Prudente. From 2010 to 2015, 40,309 dogs were serologically screened and 638 showed positive results, i.e. a prevalence rate of 1.6%. From 2013 to 2017, six human cases were diagnosed with a mortality rate of 33.3%. In 2015, 56 points of irregular solid-waste deposits were identified, predominantly in the neighborhoods. Three different hotspots of CVL showed an increased distribution of vectors, seropositive dogs, irregular solid-waste deposits, forest fragments and water drainage.

Conclusions

The use of tools that analyze the spatial distribution of vectors, canine and human VL as environmental risk factors were essential to identifying the areas most vulnerable to the spread or maintenance of VL. The results may help public health authorities in planning prevention and control measures to avoid expansion and future outbreaks.

Immunohistochemical characterization of cutaneous leishmaniasis in cats from Central-west Brazil

Feline leishmaniasis (FeL) is an emerging infectious disease of cats caused by Leishmania infantum with global distribution. This study investigated the cause of chronic progressive cutaneous lesions in two cats from Central-west Brazil by using cytological, histopathologic, and immunohistochemical (IHC) analyses. Clinically, both cats had ulcerative cutaneous lesions at the nasal planum and ear resulting in a tentative diagnosis of squamous cell carcinoma (SCC). Moreover, both cats had varying degrees of onychogryphosis. However, cytology revealed chronic inflammatory reactions associated with intralesional amastigotes; histopathology confirmed chronic ulcerative dermatitis associated with intralesional and intracytoplasmic parasitic organisms consistent with amastigotes of Leishmania spp. within histiocytes. The IHC assay demonstrated that the intralesional parasitic structures identified by cytology and histopathology were immunoreactive to antigens of Leishmania spp., confirming the participation of this infectious disease agent in the development of the cutaneous lesions of these cats. The observation of onychogryphosis must be highlighted, since this lesion is frequently observed in dogs with visceral leishmaniasis but is underreported in FeL. Collectively, the pathologic and IHC findings of the chronic cutaneous disease confirmed active infections due to Leishmania spp. in these cats. Additionally, FeL with associated lesions to the ear and nasal planum must be considered as differential diagnosis for SCC in cats.

Seroprevalence of canine Leishmania infantum infection in the Mediterranean region and identification of risk factors: The example of North-Eastern and Pyrenean areas of Spain

The Mediterranean basin is an endemic region for canine leishmaniosis (CanL), where it represents a major veterinary problem and raises human health concerns. However, the distribution of the disease is heterogeneous and not all countries and locations have been equally studied and characterized. This work describes the situation of CanL in Girona province (Catalonia, Spain), for which no data has been previously reported, and presents a relevant study to exemplify other areas with similar characteristics across the region. Four cross-sectional seroprevalence surveys were performed from 2012 to 2016 throughout the province, including 36 sampling stations in 26 localities and a total of 593 dogs. For each animal, individual and location variables were also collected. Additionally, each dog owner answered a questionnaire about their knowledge of CanL and preventive methods used. Blood samples were analysed by an in-house ELISA and a mixed logistic regression model was used to assess the relationship between pre-determined variables and dog seropositivity. A Spearman's correlation was used to assess the association between dog owners' perceived risk of CanL and Leishmania infantum seropositivity in dogs at a given location. The overall true seroprevalence estimated for Girona province was 19.5% (95%CI: 15.5-23.5), of which only 6.8% (10/146) were considered symptomatic. Age of the dog [OR = 1.21 (95%CI: 1.11-1.31); p < 0.001] and altitude [OR = 0.02 (95%CI: 0.001-0.19); p = 0.001] were identified as risk factors for the infection. The results obtained in this study are expected to aid in the implementation of directed control programmes in CanL endemic areas throughout Europe, as well as to provide suitable data for the design of better risk assessment maps of the disease.

Immunohaematological and rheological parameters in canine visceral leishmaniasis

The aim of this study was to find correlations between haematological and rheological parameters in canine visceral leishmaniasis (CLV). Enrolled dogs with CVL (n=31) had a confirmed diagnosis using the rapid test Dual Path Platform (TR DPP®) kit and Polymerase Chain Reaction (PCR) assay. A control group (n=31) comprised healthy dogs with negative results for the TR DPP® kit and PCR assay. Haematological parameters and total protein, albumin, globulin, and antibody were assessed. The rheological properties of the blood samples were also determined. Erythrocytes, haematocrit and platelet values of dogs in the CVL group were found to be lower than those of the control group. The total protein, globulin and IgG concentrations were higher in serum samples from the CVL group. The blood flow curve demonstrated increased shear rates in the CVL group. The viscosity of the blood from the infected animals was lower than in the healthy dogs. A positive correlation was found between erythrocyte numbers and blood viscosity. These data suggest that changes in the flow curve and viscosity of blood as well as the erythrocyte values may be a viable low-cost alternative for the monitoring of dogs with visceral leishmaniasis.

High seroprevalence and peripheral spatial distribution of visceral leishmaniasis among domestic dogs in an emerging urban focus in Central Brazil: a cross-sectional study

The Brazilian municipality of Rondonópolis is an emerging urban focus of intense transmission of visceral leishmaniasis (VL), where few investigations have addressed canine reservoirs. This study assessed the seroprevalence and spatial distribution of canine visceral leishmaniasis (CVL) in the urban area of Rondonópolis. A CVL serosurvey was conducted between October 2016 and February 2017 using an immunochromatographic rapid test and enzyme-linked immunosorbent assay. Domestic dogs were sampled from 25 heterogeneous regions previously defined by the Spatial 'K'luster Analysis by Tree Edge Removal algorithm, which considered the socioeconomic and environmental features from the last demographic census. The CVL spatial distribution was analyzed by kernel density estimation (KDE) and spatial scan statistic. All the  autochthonous human VL cases reported between 2014 and 2016 were georeferenced. Of the 600 dogs tested, 115 were seropositive in both tests. The overall CVL prevalence was 19.2% (95%CI: 16.1-22.3%), which varied widely among the evaluated regions (0.0-35.1%). Almost 25% of the sampled households (n = 405) had at least one infected dog. KDE demonstrated that positive CVL households were concentrated in the peripheral areas of the city. Spatial scan statistics detected a spatial cluster with significantly low CVL prevalence in the central region (relative risk = 0.37; p = 0.04), where only one human VL case was reported. Thus, we demonstrated a high prevalence of CVL in domestic dogs from diverse socioeconomic and environmental urban contexts in Rondonópolis. The CVL cases were peripherally distributed and occurred more frequently in areas that had reported human VL.

Seroprevalence of Toxoplasma gondii in dogs of riverside communities of Mato Grosso Pantanal, Brazil

Abstract Toxoplasma gondii is an intracellular protozoan with worldwide distribution and dogs act as sentinels of human infection. This search aimed to determine the occurrence of antibodies against T. gondii in dogs of the communities on the Cuiabá River, Mato Grosso and variables associated with infection. The dogs of the riverside communities in Cuiabá River, which includes Barranco Alto, Praia do Poço, Engenho Velho, Varginha, Bom Sucesso, Passagem da Conceição and São Gonçalo Beira Rio, were evaluated for the presence of T. gondii antibodies by indirect immunofluorescence antibody test (IFAT). The prevalence and factors associated with infection were calculated by chi-squared test (χ2) or Fisher’s exact test, and univariate and multiple analysis. Of the 248 dogs surveyed, 107 (43.1%) were seropositive for T. gondii. The seroprevalence ranged from 25.6% to 64.3%. There was no statistically significant difference between the communities studied (p > 0.05). As for the associated factors, the only statistically significant factor was that of dogs living with cats (p = 0.02), with approximately twice the risk of acquiring infection. In conclusion, the seroprevalence in dogs of riverside communities in the Baixada Cuiabana demonstrated that high rates of infection, being the factor associated with infection, contact with domestic cats.

Canine-Based Strategies for Prevention and Control of Visceral Leishmaniasis in Brazil

Visceral leishmaniasis (VL) is a zoonosis found worldwide. Its incidence has increased in Brazil in recent years, representing a serious public and animal health problem. The strategies applied in Brazil are questionable and are not sufficient to control the disease. Thus, we have compared the efficacy of some of the currently available strategies focused on dogs to prevent and control zoonotic VL in endemic areas by optimizing a mathematical model. The simulations showed that the elimination of seropositive dogs, the use of insecticide-impregnated dog collars, and the vaccination of dogs significantly contribute to reducing the prevalence of infection in both canines and humans. The use of insecticide-impregnated collars presented the highest level of efficacy mainly because it directly affected the force of infection and vector-dog contact. In addition, when used at a coverage rate of 90%, insecticide-impregnated collar was able to decrease the prevalence of seropositive dogs and humans to zero; moreover, because of the easy application and acceptance by the targeted population, these collars may be considered the most feasible for inclusion in public policies among the three simulated measures. Vaccination and euthanasia were efficacious, but the latter method is strongly criticized on ethical grounds, and both methods present difficulties for inclusion in public policies. When we compared the use of euthanasia and vaccination at coverages of 70 and 90%, respectively, the proportion of infected populations were similar. However, on evaluating the implications of both of these methods, particularly the negative aspects of culling dogs and the proportion of animals protected by vaccination, the latter measure appears to be the better option if the total cost is not significantly higher. The comparison of complications and advantages of different control strategies allows us to analyze the optimal measure and offer strategies to veterinary and public health authorities for making decisions to prevent and control zoonotic VL. Hence, improvements in both public and animal health can be achieved in regions with scenarios similar to that considered in the present study; such scenarios are characteristically found in some areas of Brazil and other countries.

Current status on prevention and treatment of canine leishmaniasis

Canine leishmaniasis (CanL) is a parasite-borne disease mainly induced by Leishmania infantum in the Old World and Leishmania chagasi (infantum) in the New World. CanL is a zoonosis transmitted by the bite of infected Phlebotominae flies that act as vectors. CanL is a very serious disease that usually produces death when remains untreated and can be a focus of transmission to other dogs or humans. Infected dogs and other domestic and wild animals act as reservoirs and are a real threat to uninfected/healthy dogs and humans in endemic areas where the sand flies are present. Prevention of new infections in dogs can help to stop the current increase of the disease in humans, reinforcing the concept of "One Health" approach. The management of CanL is being performed using prophylactic measures in healthy dogs - insecticides impregnated in collars or immunostimulants applied by spot-on devices - and chemotherapy in animals that suffer from the disease. Antimonials as first-line monotherapy have proven efficacy in reducing most of the clinical signs of CanL, but they need to be administered during several days, and no complete parasite clearance is achieved, favouring the presence of relapses among treated dogs. Therefore, new drugs, such as miltefosine, or combinations of this drug or antimonials with allopurinol are in the pipeline of clinical treatment of CanL. Recently, there has been an emergence of protective - prophylactic - and curative - autogenous vaccines - immunotherapy tools to face CanL, whose results are still under study. This review highlights the current use of preventive and eradicative weapons to fight against this disease, which is a scourge for dogs and a continuous threat to human beings.

Risk factors associated with seropositivity for Leishmania spp. and Trypanosoma cruzi in dogs in the state of Paraiba, Brazil

Abstract The aim of this survey was to determine the seropositivity and risk factors forLeishmania spp. and Trypanosoma cruzi in dogs in the State of Paraíba, Northeastern Brazil. A total of 1,043 dogs were tested, and the serological diagnoses of Chagas disease (CD) and canine visceral leishmaniasis (CVL) was performed by the indirect fluorescent antibody test (IFAT). Animals that tested seropositive for both diseases (by IFAT) were further subjected to ELISA. Of the 1,043 dogs 81 (7.8%; 95% CI = 6.1-9.4%) tested seropositive for Leishmania spp., while 83 were seropositive for T. cruzi (7.9%; 95% CI = 6.3-9.6%). Simultaneous serological reactions were detected in 49 animals (4.6%; 95% CI= 3.6-6.2%). Semi-domiciled housing (OR = 2.044), free housing (OR = 4.151), and soil (OR = 3.425) and soil/cement (OR = 3.065) environmental conditions were identified as risk factors for CVL seropositivity. The risk factors identified for CD seropositivity were semi-domiciled (OR = 2.353) or free housing (OR = 3.454), and contact with bovine (OR = 2.015). This study revealed the presence of dogs in the Paraíba State seropositive for CVL and CD, suggesting the need for revisiting and intensification of disease control measures through constant monitoring of the canine population.

Factors associated with the seroprevalence of leishmaniasis in dogs living around Atlantic Forest fragments

Canine visceral leishmaniasis is an important zoonosis in Brazil. However, infection patterns are unknown in some scenarios such as rural settlements around Atlantic Forest fragments. Additionally, controversy remains over risk factors, and most identified patterns of infection in dogs have been found in urban areas. We conducted a cross-sectional epidemiological survey to assess the prevalence of leishmaniasis in dogs through three different serological tests, and interviews with owners to assess features of dogs and households around five Atlantic Forest remnants in southeastern Brazil. We used Generalized Linear Mixed Models and Chi-square tests to detect associations between prevalence and variables that might influence Leishmania infection, and a nearest neighbor dispersion analysis to assess clustering in the spatial distribution of seropositive dogs. Our findings showed an average prevalence of 20% (ranging from 10 to 32%) in dogs. Nearly 40% (ranging from 22 to 55%) of households had at least one seropositive dog. Some individual traits of dogs (height, sterilization, long fur, age class) were found to positively influence the prevalence, while some had negative influence (weight, body score, presence of ectoparasites). Environmental and management features (number of cats in the households, dogs with free-ranging behavior) also entered models as negative associations with seropositivity. Strong and consistent negative (protective) influences of the presence of chickens and pigs in dog seropositivity were detected. Spatial clustering of cases was detected in only one of the five study sites. The results showed that different risk factors than those found in urban areas may drive the prevalence of canine leishmaniasis in farm/forest interfaces, and that humans and wildlife risk infection in these areas. Domestic dog population limitation by gonadectomy, legal restriction of dog numbers per household and owner education are of the greatest importance for the control of visceral leishmaniasis in rural zones near forest fragments.

Epidemiological aspects of visceral leishmaniasis in Jaciara, Mato Grosso, Brazil, 2003 to 2012

Visceral leishmaniasis (VL) is caused by Leishmania (L.) infantum chagasi in the Americas. In Brazil, it is transmitted by sandflies of the species Lutzomyia longipalpis and L. cruzi, and dogs are the main domestic reservoirs. The aim of this study was to analyze data relating to VL transmission in Jaciara, state of Mato Grosso, and discuss vector distribution, domestic reservoirs, and human cases that occurred between 2003 and 2012. The data for analysis were obtained from the Notifiable Diseases Information System (human), the State Health Department's Environmental Monitoring Agency (canine data) and the State Health Department's Entomology Laboratory (sandfly data). Over this period, Jaciara had 19 autochthonous human cases (12 males and seven females), with one death 2,273. Out of the 7,545 dogs tested by enzyme immunoassay and indirect immunofluorescence were positive. The sandflies collected comprised 5,015 individuals belonging to 24 species, with a predominance of L. whitmani followed by L. cruzi. The results showed that the parasite has frequent circulation and that the vector L. cruzi is widely distributed over all months, thus suggesting that transmission may occur at any time of the year.

Canine visceral leishmaniasis: diagnostic approaches based on polymerase chain reaction employing different biological samples

The accurate diagnosis of canine visceral leishmaniasis (CanL) is essential for visceral leishmaniasis control. To this end, DNA detection on different biological samples has been employed. In this study, we report the use of polymerase chain reaction (PCR) assay on samples such as buffy coat, bone marrow, intact skin and cutaneous ulcers fragments, and lymph node aspirate collected from 430 dogs to determine the suitable biological sample for use in CanL diagnosis. The PCR results were correlated with clinical status and other tests previously performed. Leishmania chagasi DNA was detected in 14.6% (n = 63) of the dogs investigated, regardless of the sample analyzed. Our results showed that symptomatic cases were easily diagnosed when compared to asymptomatic animals; however, the PCR proved to be very useful for Leishmania DNA detection, mainly in lymph node aspirate (41; 9.6%), irrespective of the clinical status of the dog. The finding that the lymph node aspirate produced high positivity rates and the fact that this specimen was obtained by noninvasive methods highlight its use in epidemiological survey by PCR for CanL diagnosis.