Prevalence Of Canine Visceral Leishmaniasis Research Articles

Responsible companion animal guardianship is associated with canine visceral leishmaniasis: an analytical cross-sectional survey in an urban area of southeastern Brazil

BackgroundResponsible companion animal guardianship (RCAG) comprises a set of concepts involving activities, behavior and care that guardians must provide to ensure the welfare of their animals. When such principles are disregarded, the risk of animals developing zoonotic diseases, such as canine visceral leishmaniasis (CVL), increases. This disease is a public health problem in many urban settings in Brazil because dogs are the main reservoirs of Leishmania and are involved in the transmission of the parasites to humans. Our analytical cross-sectional epidemiological survey aimed to investigate the prevalence of CVL in a city in southeastern Brazil and to establish the association between the disease and a number of predictor variables including dog traits, socioeconomic status of guardians, ecological features of the domicile and RCAG.ResultsOur study showed that the global prevalence of CVL in the sample canine population was 6.7% (47/704). All variables related to better dog care were associated with lower chances of infection. Multiple regression analysis revealed that the chances of animals being seropositive for CVL were significantly (p < 0.05) higher when guardians had no formal education or possessed a university degree (vs. those with complete primary or secondary schooling) and when dogs were sheltered outside the house and had free access to the streets. An additional novel finding was that dogs that were acquired as puppies presented half of the chance of developing the disease in comparison with those acquired at the adult stage. Geographically weighted logistic regression coefficients showed that the strengths of the predictor/CVL associations varied depending on the studied geographical space. Both models demonstrated that the associations were always in the same directions.ConclusionsOur findings indicate that regardless of age and mode of acquisition, adult dogs should be submitted to clinical evaluation and tests for CVL. RCAG can exert positive effects on the control of CVL.

The first case of canine visceral leishmaniasis in the southern region of Santa Catarina, an emerging focus of visceral leishmaniasis in Brazil: regional report or reflection of the reality of a country?

Visceral leishmaniasis is among the most neglected diseases in the world and especially affects poor populations of some developing or underdeveloped countries, with human disease being a factor in the occurrence of thousands of deaths every year. Visceral leishmaniasis affect domestic dogs, main reservoirs of the Leishmania parasite in urban environments. Thus, the aim of this study was to analyze the prevalence of canine visceral leishmaniasis in two non-endemic municipalities located in southern Santa Catarina, as well as to identify the main risk factors for infection in dogs. A cross-sectional study was carried out with dogs living in two Zoonoses Control Centers located in the cities of Tubarão and Criciúma. Blood samples were collected and analyzed by real-time PCR for detection of Leishmania infection. Clinical examination and evaluation of the characteristics of the canine population were also carried out. A total of 107 dogs were evaluated, of which 19% were positive for Leishmania, and 85% of the positive cases were asymptomatic. In conclusion, we highlight the detection of cases of canine visceral leishmaniasis in two cities that had not yet reported cases. The high rate of positive asymptomatic animals suggests the maintenance of the parasite in the environment.

Molecular and Serological Analysis for Prevalence of Canine Visceral Leishmaniasis in the Muğla Region of Turkey

This study aimed to determine the prevalence of canine visceral leishmaniasis by molecular and serological techniques among owned dogs brought to veterinary clinics in the Muğla region of Turkey. Blood samples were collected from a total of 131 dogs of different breeds and gender that were brought to veterinary clinics between October 2017 and November 2018 in the Muğla region. These blood samples were analysed using immunofluorescent antibody test (IFAT) and polymerase chain reaction (PCR). According to the IFAT results, 49 out of 131 dogs (37.4%) were found to have anti-Leishmania antibodies at a titer of ≥1/64, which was considered as seropositive. On the other hand, PCR results obtained in this study showed that 9 out of 131 dogs (6.87%) were Leishmania spp. positive by RV1/RV2 PCR. The results suggest that there is a need to focus on developing measures to control the disease, fight the vector Phlebotom and initiate disease control programmes for dogs in the Muğla region.

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.

Characterization of a municipality as free of canine visceral leishmaniasis in the context of One Health.

Dogs are the main urban reservoir of Leishmania infantum, the causative agent of visceral leishmaniasis (VL), which is transmitted by sand flies. In the state of Paraná, the first detection of a positive dog for VL was in 2014, this year Paraná lost free status for this disease (VL). The objectives of this study were to determine the prevalence of canine visceral leishmaniasis in Palotina, the occurrence of vectors that may transmit Leishmania infantum, and the number of notifications of human visceral leishmaniasis cases from period 2010 to 2020. To determine the occurrence of canine visceral leishmaniasis, blood samples from 204 dogs were analyzed using the rapid test DPP® to detect anti-L. infantum antibodies. To investigate the occurrence of potential vectors, monthly collections were made at 18 points within the urban area of the municipality. The number of human visceral leishmaniasis cases was investigated from Epidemiological Surveillance records. None of the serologically tested dogs showed positive titration. Only two specimens of Lutzomyia neivai, one of Lutzomyia sp. and four of Brumptomyia brumpti specimens were collected. No human visceral leishmaniasis cases were reported. These results suggest that there is no evidence of circulation of L. infantum in Palotina.

Molecular and Seroepidemiological Survey of Visceral Leishmaniasis in Owned Dogs (Canis familiaris) in New Foci of Rural Areas of Alborz Province, Central Part of Iran: A Cross-Sectional Study in 2017

Background:Mediterranean form of visceral leishmaniasis (VL) is endemic among some provinces of Iran. The present study was designed to determine the prevalence of canine visceral leishmaniasis (CVL) in the owned dogs of the rural areas of Alborz Province near Tehran as the capital of Iran.Methods:This study conducted on 303 owned dogs that selected using a stratified random sampling method. The direct agglutination test (DAT) was used to determine the frequency of Vl. The spleen biopsy was taken from the serology-positive dogs for the confirmation of CVL in the suspected dogs. Nested PCR and sequencing methods were used to determine the type of Leishmania species in the dogs which were parasitological positive.Results:Overall, the DAT results of 9 dogs (2.97%, CI: 1.57–5.55) showed anti Leishmania antibodies at titers ≥ 1:320 indicating VL infection. One dog (0.33%, CI 95%: 0.06–1.85) showed clinical signs and symptoms of VL. There was a significant correlation between the positive cases of CVL and rural area (p< 0.001). The Leishmania was observed in the impression smears that were prepared from spleen biopsy of five the studied dogs. Leishmania infantum were confirmed in all them using nested–PCR assay. The sequence analysis of all five isolates was 95% similar to L. infantum.Conclusion:This study shows that domestic cycle of L. infantum has been established in rural areas of Alborz province where located near Tehran as capital city of Iran. It is necessary to increase the awareness and monitoring of the disease periodically.

Dogs with divergent serology for visceral leishmaniasis as sources of Leishmania infection for Lutzomyia longipalpis phlebotomine sand flies - an observational study in an endemic area in Brazil.

Visceral leishmaniasis (VL) is a neglected tropical disease, caused by Leishmania (Kinetoplastida, Trypanosomatidae) species. In Brazil, the transmission of this parasite essentially occurs through the bite of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) previously infected with Leishmania infantum. Aiming at preventing VL expansion over the country, integrated control actions have been implemented through a Visceral Leishmaniasis Surveillance and Control Program (VLSCP). Among the actions currently adopted by the program, the screening-culling of seropositive dogs for canine VL (CVL) is particularly polemic. Dogs with negative or divergent serology for CVL remain in their owner’s domicile and are monitored by public health agents. In the present study, we determined the prevalence of CVL and analyzed the implementation of the VLSCP screening-culling action, in an area in Brazil where there has been a recent expansion of VL. Canine census surveys were conducted semiannually for two years (Aug/2015 to Feb/2017). Serological diagnosis of CVL was performed in accordance with current VLSCP protocol: immunochromatography (TR-DPP) followed by enzyme-linked immunosorbent assay (ELISA EIE). 6,667 dogs were serologically screened for CVL, of which 567 (8.5%) were positive in both tests and 641 (9.6%) had divergent results. A variable percentage (6.3% to 65.4%) of the dogs in the latter group became positive within nine months from the first result. Xenodiagnosis was conducted in canine samples belonging to any of the three possible serological statuses for CVL–positive, divergent or negative. Leishmania spp. DNA was detected in Lu. longipalpis that fed on 50.0% (5/10) of dogs with positive serology and on 29.4% (5/17) of dogs with divergent serological status for CVL. Therefore, dogs with divergent serology for CVL may be as Leishmania-infective to Lu. longipalpis as seropositive ones. Even with the adoption of euthanasia for seropositive dogs, part of the canine population will continue to serve as a source of Leishmania infection for phlebotomine sand flies.

Evaluation of the euthanasia of seropositive dogs for canine visceral leishmaniasis as the only method of controling the disease in the enzootic area in the Midwestern Minas Gerais

ABSTRACT: Human Visceral Leishmaniasis (VL) is expanding, and it is distributed in the five geographic regions of Brazil, with the Northeast being the region that presents the most significant number of registered cases. The main urban reservoir of the etiological agent of VL is the domestic dog, and it is known that canine cases precede human cases. One of the control actions of VL, recommended by the Ministry of Health, is performing the euthanasia of seropositive dogs. In 2013, in the municipality of Iguatama/MG, the first canine serological survey was carried out in the city, with a prevalence of 8.3% of seropositive dogs for Leishmania infantum. Of the seropositive animals for Canine Visceral Leishmaniasis (CVL) in this survey, 84% were euthanized, and 16% died within two years after diagnosis. No other control measures for CVL were taken in the municipality. The objectives of the present study were to determine the current prevalence of seropositive dogs for CVL in the municipality of Iguatama and to observe the impact of euthanasia of seropositive dogs to VL as the only control measure performed in this municipality, which is considered an enzootic area of the disease. For this, a new canine epidemiological survey was carried out in the municipality of Iguatama, following the guidelines of the Manual of Surveillance and Control of Visceral Leishmaniasis. Blood samples were collected from 270 dogs and tested by DPP® immunochromatographic test and by Enzyme-Linked Immunosorbent Assay (ELISA). The animals that presented inconclusive results had new blood samples collected and analyzed. The only animal that showed a positive result in DPP® and undetermined in the ELISA, in the first evaluation, became seropositive four months later, so this study reinforces the recommendation of the Ministry of Health to reassess dogs that present inconclusive results for CVL. From a total of 270 samples, 21 (7.8%) were reagents in both tests. Thus, the prevalence of seropositive dogs for CVL, in 2017, in the urban area of the municipality of Iguatama was 7.8%. The Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) molecular technique confirmed infection by L. infantum in the ten dogs sampled with CVL-positive serology. The comparison between the current prevalence (after euthanasia) with that found in 2013 (8.3%), there was no significant difference (p=0.764). The prevalence of CVL in the urban area of the municipality of Iguatama is still high, making it possible to presume that the euthanasia of seropositive dogs for CVL, and the absence of monitoring or other interventions measures, did not contribute to decrease the transmission of the parasite and was not sufficient for the control of CVL in the municipality of Iguatama, an area considered as non-endemic to CVL until 2013.

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.

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.

PREVALÊNCIA DA LEISHMANIOSE VISCERAL CANINA E COINFECÇÕES EM REGIÃO PERIURBANA NO DISTRITO FEDERAL – BRASIL

Resumo Objetivou-se verificar a prevalência da leishmaniose visceral canina (LVC) em área periurbana com foco de transmissão no Distrito Federal (DF) e também avaliar a prevalência de coinfecções como dirofilariose, anaplasmose, erliquiose e doença de Lyme em cães sororreagentes para LVC. Inicialmente, amostras de soros dos cães da área de estudo foram testadas à reação imunocromatográfica que contém dois antígenos recombinantes ̶ rK39 e rK26 − (DPP) para Leishmania sp. O soro dos animais reagentes ao teste de DPP foi confirmado para LVC com ELISA. As amostras reagentes a ambos os testes foram analisadas para possíveis coinfecções através do teste de SNAP (IDEXX 4Dx Plus). Foram avaliados 240 cães, dos quais 132 (55%) obtiveram resultados reagentes para DPP e para ELISA concomitantemente, sendo diagnosticados com LVC. Destes, 26 (20%) foram reagentes para Ehrlichia canis ou E. ewangii, 9 (7%) apresentaram positividade para Anaplasma phagocytophilum ou A. platys e, nessas amostras que se apresentaram reagentes, observou-se a ocorrência de coinfecção de anaplasmose, erliquiose e leishmaniose em 3 (2,3%) animais. Verificou-se alta prevalência da LVC na região periurbana do DF, destacando-se a necessidade de diagnóstico mais preciso quanto a coinfecções que possivelmente podem influenciar no prognóstico e manifestação do quadro clínico desses pacientes.

Molecular Method Confirms Canine Leishmania Infection Detected by Serological Methods in Non-Endemic Area of Brazil

In Brazil, visceral leishmaniasis (VL) is expanding and becoming urbanized, especially in non-endemic areas such as the State of Rio Grande do Sul. Considering that infected dogs are the main reservoir for zoonotic VL, this study evaluated the prevalence of canine visceral leishmaniasis (CVL) in the metropolitan area of Porto Alegre, a new area of expansion of VL in Brazil. Serum and plasma from 405 asymptomatic dogs from the municipalities of Canoas (n=107), São Leopoldo (n=216), and Novo Hamburgo (n=82) were tested for CVL using immunochromatographic (DPP®) and ELISA EIE® assays (2 assays officially adopted by the Brazilian government for the diagnosis of CVL) and real-time PCR to confirm the results. There was no agreement among serological and real-time PCR results, indicating that the Leishmania infection in asymptomatic animals with low parasite load, confirmed by negative parasitological tests (smears and parasite culture), need to be evaluated by molecular methods. The prevalence of LVC in the metropolitan region of Porto Alegre, confirmed by real-time PCR was 4% (5.6% in Canoas and 4.6% in São Leopoldo). The use of molecular method is essential for accurate diagnosis of CVL, especially in asymptomatic dogs in non-endemic areas.

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.

Canine visceral leishmaniasis in Iran: A systematic review and meta-analysis

Visceral leishmaniasis is considered an endemic zoonosis in some parts of Iran and dogs are main reservoirs, which play role in the transmission cycle of human leishmaniasis. This systematic review and meta-analysis was performed to determine the prevalence of canine visceral leishmaniasis (CVL) in Iran. Data were systematically collected from 1982 to 2015 in Iran on the following electronic databases: PubMed, Google Scholar, Science Direct, Scopus, Web of Science, Magiran, Irandoc, Iran medex and Scientific Information Database (SID). A total of 39 articles concerning dogs, 6 articles on jackals, 4 articles on wolves and 4 articles on foxes, reporting the prevalence of CVL from different regions of Iran fulfilled our eligibility criteria. Totally, 19903 dogs, 151 jackals, 42 wolves and 44 foxes were examined and the overall prevalence rate of CVL in Iran was estimated to be as following: in dogs 16% (95% CI: 13–19%), in jackals 10% (95% CI: 5–15%), in wolves 10% (95% CI: 5–15%) and in foxes 10% (95% CI: 1k19%), respectively. There was a significant difference in infection rate between male and female dogs, the infection in males 9% (95% CI: 8.8–10.5%) was more than females 7% (95% CI: 5.5–7.5%) (p=0.024). Also, the rate of infection was significantly higher in older dogs than younger ones (p<0.047) while in dogs younger than 1year was 12% (95% CI: 6–18%), in 1–2 years 10% (95% CI: 6–14%), in 3–5 years 16% (95% CI: 9–22%) and in those which were over 7 years 31% (95% CI: 19–44%), respectively. Our meta- regression analysis revealed the significant correlation between stray and owned dogs: the infection rate in stray 10% (95% CI: 5–4%) was higher than those owned 6% (95% CI: 3- 8%) (p=0.037). Also, the prevalence of infection in rural dogs 36% (95% CI: -1–72%) is significantly higher than urban dogs, 19% (95% CI:-1–40%) (p=0.013). Although most (81%) of infected dogs had no clinical signs (asymptomatic), meta-regression analysis showed that the infection rate in asymptomatic dogs was 14% (95% CI: 11–18%) and in those with clinical signs 3% (95%CI: 2–4%), and the correlation is statistically significant (p=0.001). The present systematic review and meta-analysis indicates that CVL is common at least in some districts of more than half of provinces of Iran. Further investigation and monitoring will be required to improve the surveillance and control strategies to reduce the incidence of CVL in Iran.

Leishmaniose Canina em Brasília, DF: Uma Revisão da Literatura.

A leishmaniose é uma doença infecto-parasitária que acomete seres humanos e animais, causada por protozoários do gênero Leishmania. As leishmanioses são importante problema de saúde pública em vários países e estão incluídas entre as seis endemias de maior relevância mundial. São classificadas em tegumentar (LT) cutânea e mucocutânea - e visceral (LV). A transmissão ocorre através de picada de insetos flebotomíneos pertencentes aos gêneros Lutzomyia (Novo Mundo) e Phlebotomus(Velho Mundo). A Leishmaniose Tegumentar Americana (LTA) é uma zoonose distribuída no território brasileiro. Possui evolução crônica e acomete a pele e mucosas, isoladamente ou em associação, de seres humanos, cães, gatos e eqüinos. Nos cães, se caracteriza pela presença de lesões cutâneas ulceradas, recobertas por crostas, localizadas nas orelhas, bolsa escrotal, focinho e membros. A Leishmaniose visceral é uma zoonose que ocorre nas regiões subtropicais e tropicais, causada pela Leishmania (Leishmania) chagasi, no Novo e no Velho Mundo. No Brasil, a Leishmaniose Visceral Canina (LVC) coexiste com a doença humana e os cães são seu reservatório doméstico. A eutanásia do cão é criticada por isso enfrenta limitações. Apesar das ações de vigilância e controle de LV adotadas no DF, a doença permanece em áreas urbanas e rurais.

Prevalence of Canine Visceral Leishmaniasis in the Xakriabá Indigenous Land, Minas Gerais State, Southeast Brazil, 2011.

Prevalence of Canine Visceral Leishmaniasis in the Xakriabá Indigenous Land, Minas Gerais State, Southeast Brazil, 2011.

Awareness of visceral leishmaniasis and its relationship to canine infection in riverside endemic areas in Northeastern Brazil.

An awareness of visceral leishmaniasis (VL) is necessary to encourage the population to participate in prevention and control in collaboration with more efficient, centrally organized health programs. The aim of this study was to evaluate the awareness of the riverside population regarding VL and the association between awareness and the prevalence of canine visceral leishmaniasis (CVL). In total, 71 people living in riverside areas in the City of Mossoró in State of Rio Grande do Norte participated of the study, and 71 dogs were tested for CVL by polymerase chain reaction (PCR). Association analysis of several variables related to knowledge of the riverside population regarding CVL positivity was performed, yielding odds ratios (OR) and 95% confidence intervals (CI), and significance was determined using chi-square (χ2) and Fisher's exact tests. Among individuals whose dogs tested positive for CVL, 60% did not know the cure for CVL, and these subjects were three times more likely to have a dog test positive for CVL than those who were aware the cure for CVL. Knowledge of CVL cure was the only variable that remained in the logistic model after the successive removal of variables, with an adjusted OR of 3.11 (95%CI: 1.1-8,799; p=0.032). Insufficient awareness regarding VL in riverside areas with CVL-positive dogs was associated with increased rates of canine infection, which suggests that changes in habits and the adoption of attitudes and preventive practices may contribute to the control and prevention of this disease. This study reinforces the need to invest in better health education programs regarding VL.

Evaluation of Change in Canine Diagnosis Protocol Adopted by the Visceral Leishmaniasis Control Program in Brazil and a New Proposal for Diagnosis

The techniques used for diagnosis of canine visceral leishmaniasis (CVL) in Brazil ELISA and IFAT have been extensively questioned because of the accuracy of these tests. A recent change in the diagnosis protocol excluded IFAT and included the Dual-Path Platform (DPP). We evaluated the prevalence and incidence rates of Leishmania spp. before and after the change in the protocol. In addition, based on our results, we propose a new alternative that is less expensive for the screening and confirmation of CVL. Plasma samples were obtained from a serobank from dogs evaluated in a cross-sectional study (1,226 dogs) and in a cohort study of susceptible animals (n = 447), followed for 26 months. Serology testing was performed using ELISA, IFAT, and DPP. The incidence and prevalence of CVL were determined by using the protocol of the Visceral Leishmaniasis Control and Surveillance Program until 2012 (ELISA and IFAT using filter paper) and the protocol used after 2012 (DPP and ELISA using plasma). The prevalence was 6.2% and the incidence was 2.8 per 1,000 dog-months for the protocol used until 2012. For the new diagnosis protocol for CVL resulted in an incidence of 5.4 per 1,000 dog-months and a prevalence of 8.1%. Our results showed that the prevalence and incidence of infection were far greater than suggested by the previously used protocol and that the magnitude of infection in endemic areas has been underestimated. As tests are performed sequentially and euthanasia of dogs is carried out when the serological results are positive in both tests, the sequence does not affect the number of animals to be eliminated by the Control Program. Then we suggest to municipalities with a large demand of exams to use ELISA for screening and DPP for confirmation, since this allows easier performance and reduced cost.

Culling Dogs in Scenarios of Imperfect Control: Realistic Impact on the Prevalence of Canine Visceral Leishmaniasis

BackgroundVisceral leishmaniasis belongs to the list of neglected tropical diseases and is considered a public health problem worldwide. Spatial correlation between the occurrence of the disease in humans and high rates of canine infection suggests that in the presence of the vector, canine visceral leishmaniasis is the key factor for triggering transmission to humans. Despite the control strategies implemented, such as the sacrifice of infected dogs being put down, the incidence of American visceral leishmaniasis remains high in many Latin American countries.Methodology/Principal FindingsMathematical models were developed to describe the transmission dynamics of canine leishmaniasis and its control by culling. Using these models, imperfect control scenarios were implemented to verify the possible factors which alter the effectiveness of controlling this disease in practice.Conclusions/SignificanceA long-term continuous program targeting both asymptomatic and symptomatic dogs should be effective in controlling canine leishmaniasis in areas of low to moderate transmission (R0 up to 1.4). However, the indiscriminate sacrifice of asymptomatic dogs with positive diagnosis may jeopardize the effectiveness of the control program, if tests with low specificity are used, increasing the chance of generating outrage in the population, and leading to lower adherence to the program. Therefore, culling must be planned accurately and implemented responsibly and never as a mechanical measure in large scale. In areas with higher transmission, culling alone is not an effective control strategy.

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.