Forty years of visceral leishmaniasis in the State of Piaui: a review

[Epidemiological profile and time trend in visceral leishmaniasis: Piauí, Brazil, 2008-2018]

Visceral leishmaniasis (VL) or kala azar is one of the main neglected tropical diseases, of major importance due to the lethal nature of this zoonosis caused by protozoa of genus Leishmania. The study aimed to analyze the time trend in VL cases in the state of Piauí, Brazil, from 2008 to 2018, within the total period from 1971 to 2018. Data were obtained from the Brazilian Information System for Notificable Diseases (SINAN) and the Brazilian Mortality Information System (SIM). For burden of disease analysis, data were collected from the Institute for Health Metrics and Evaluation through the Global Burden of Diseases, Injuries, and Risk Factors (GBD Compare). Prais-Winsten regression analysis was used. A total of 2,374 cases were recorded with probable infection in the state of Piauí and 2,492 cases in residents of the state. The historical series analyzed, from 1971 to 2018, reaffirms the cyclical nature of the disease, based on the identification of epidemic peaks in 1983-1984, 1993-1994, 2003-2004, and 2013-2014. No significant alterations were identified in the trends in incidence, mortality, and case-fatality coefficients in the state. However, there was a significant increase in the incidence coefficient in the Chapada das Mangabeiras Development Territory, with an annual percent change of 17.5%, and a decrease in the Vale do Sambito Development Territory (-18.3%) and Vale do Rio Guaribas Development Territory (-8,1%). VL has a high burden of disease, measured by disability-adjusted life years, and is among the leading neglected tropical diseases in the state of Piauí. The study concludes by recommending the improvement of surveillance and control measures for this disease.

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.

Effectiveness of insecticide-impregnated collars for the control of canine visceral leishmaniasis

Visceral leishmaniasis is a neglected tropical disease widely distributed worldwide. In Brazil, the control measures adopted in the last decades have not been able to prevent the spread of the disease. This study aimed to evaluate the effectiveness of a population-based intervention using 4% deltamethrin-impregnated dog collars on the incidence of canine visceral leishmaniasis. A community intervention study was carried out in two areas of the city of Montes Claros, State of Minas Gerais, Brazil. In the control area, the preventive measures recommended by the Brazilian Program for Surveillance and Control of Visceral Leishmaniasis were implemented (culling of infected dogs and vector control with residual insecticides). In the intervention area, deltamethrin-impregnated collars were fit to domiciled dogs, in addition to the above mentioned preventive measures. At the beginning of the study, a census survey was carried out among domiciled dogs to detect the prevalence of L. infantum infection. Dogs found seronegative at recruitment were longitudinally followed-up to evaluate the incidence of infection. Monitoring of canine infection (control and intervention areas) and replacement of collars (intervention area) occurred through sequential surveys at 12, 18, and 24 months after the initial survey. At each survey, dogs were tested, and the owner answered a questionnaire about the general characteristics of the animal. Multilevel logistic regression models were used to test the effect of collars on the risk of canine infection, with households considered as aggregation units. Associations were expressed as odds ratios (OR) and respective 95% confidence intervals (95%CI). The prevalence of infection in the initial survey was 9.7% and 9.9% in the intervention and control areas, respectively (p = 0.732). Among a total of 20,477 dogs participating in the study, 9,770 were seronegative at recruitment. The cumulative incidence of infection was 4.1% in the intervention area and 7.9% in the control area (p < 0.001). In the multivariable analysis, the risk of infection was 52% lower in the intervention area as compared to the control area (OR = 0.48, 95%CI:0.39-0.59), after adjusting for the number of dogs in the house, period of recruitment, time of dog ownership, and age, sex, length of fur and breed. The use of 4% deltamethrin-impregnated dog collars was effective in reducing the incidence of canine leishmaniasis. Cost-effectiveness studies are recommended before the incorporation of collars in the arsenal of control measures of the Brazilian Program for Surveillance and Control of Visceral Leishmaniasis.

Visceral leishmaniasis and vulnerability conditions in an endemic urban area of Northeastern Brazil

BACKGROUND

Visceral leishmaniasis (VL) is considered an urban endemic that may be related to sociodemographic factors and urban infrastructure. The objective of this study was to analyze the conditions of vulnerability and the incidence of VL, and to identify the spatiotemporal pattern of the disease.

METHODS

Data on reported cases of VL were collected from 2007 to 2016. Thematic maps on the spatiotemporal distribution were produced using values normalized by the area of the neighborhoods. The primary indicators of vulnerability were normalized for later construction of the synthetic indicators of vulnerability of social structure, household structure, and urban infrastructure, and from these, a vulnerability index was developed. The bivariate global Moran index was used to verify the existence of spatial autocorrelation between the incidence of VL and the conditions of vulnerability, while the bivariate local Moran index was used to identify the existence of spatial clusters.

RESULTS

The 695 cases reported presented a diffuse distribution when the spatial pattern was evaluated. The incidence of the disease was correlated with worsened living conditions. Statistically significant clusters were revealed between the incidence of the disease and the vulnerability indicators of social structure, household structure, urban infrastructure and composite vulnerability index.

CONCLUSION

Addressing the local vulnerability conditions is important to the understanding of the distribution of visceral leishmaniasis, identifying the most susceptible areas, and planning control strategies.

[Prevalence of Chagas disease among blood donors in Piauí State, Brazil, from 2004 to 2013]

Despite the decline in prevalence of Chagas disease in Brazil, the Northeast region of the country has favorable conditions for its resurgence. The study aimed to analyze positive Chagas disease serology rates among blood donors in Piauí State from 2004 to 2013. Prevalence of positive Chagas disease serology in blood donor screening was 1%, ranging from 0.4% in the Uruçuí Regional Health District to 2.4% in the São Raimundo Nonato Regional Health District. Of the state's 220 municipalities, 58.6% reported cases. Only 34.5% of the positive samples in screening were referred for complementary tests, and 84.4% of these showed negative results. Our findings suggest the possibility of persistent vector-borne transmission in areas of Piauí State and the need for measures to improve complementary testing in positive cases detected by screening.

Risk analysis and prediction of visceral leishmaniasis dispersion in São Paulo State, Brazil

Visceral leishmaniasis (VL) is an important neglected disease caused by a protozoan parasite, and represents a serious public health problem in many parts of the world. It is zoonotic in Europe and Latin America, where infected dogs constitute the main domestic reservoir for the parasite and play a key role in VL transmission to humans. In Brazil this disease is caused by the protozoan Leishmania infantum chagasi, and is transmitted by the sand fly Lutzomyia longipalpis. Despite programs aimed at eliminating infection sources, the disease continues to spread throughout the Country. VL in São Paulo State, Brazil, first appeared in the northwestern region, spreading in a southeasterly direction over time. We integrate data on the VL vector, infected dogs and infected human dispersion from 1999 to 2013 through an innovative spatial temporal Bayesian model in conjunction with geographic information system. This model is used to infer the drivers of the invasion process and predict the future progression of VL through the State. We found that vector dispersion was influenced by vector presence in nearby municipalities at the previous time step, proximity to the Bolívia-Brazil gas pipeline, and high temperatures (i.e., annual average between 20 and 23°C). Key factors affecting infected dog dispersion included proximity to the Marechal Rondon Highway, high temperatures, and presence of the competent vector within the same municipality. Finally, vector presence, presence of infected dogs, and rainfall (approx. 270 to 540mm/year) drove the dispersion of human VL cases. Surprisingly, economic factors exhibited no noticeable influence on disease dispersion. Based on these drivers and stochastic simulations, we identified which municipalities are most likely to be invaded by vectors and infected hosts in the future. Prioritizing prevention and control strategies within the identified municipalities may help halt the spread of VL while reducing monitoring costs. Our results contribute important knowledge to public and animal health policy planning, and suggest that prevention and control strategies should focus on vector control and on blocking contact between vectors and hosts in the priority areas identified to be at risk.

Are opossums a relevant factor associated with asymptomatic Leishmania infection in the outskirts of the largest Brazilian cities?

A population survey was conducted to explore the prevalence and factors associated with Leishmania infection in the Fercal region of the Federal District. The Fercal region is a group of neighborhoods in Brasília in which the first cases of visceral leishmaniasis were described. Leishmania infection was established by a positive leishmanin test. Although other tests were performed in the study (an immunochromatographic assay (Kalazar detect^®) and a molecular assay), only the leishmanin skin test provided sufficient results for the measurement of the disease prevalence. Data on the epidemiological, clinical and environmental characteristics of individuals were collected along with the diagnostic tests. After sampling and enrollment, seven hundred people from 2 to 14 years of age were included in the study. The prevalence of Leishmania infection was 33.28% (95% CI 29.87–36.84). The factors associated with Leishmania infection according to the multivariate analysis were age of more than seven years and the presence of opossums near the home. Age is a known factor associated with Leishmania infection; however, the presence of wild animals, as described, is an understudied factor. The presence of opossums, which are known reservoirs of Leishmania, in peri-urban areas could be the link between the rural and urban occurrence of visceral leishmaniasis in the outskirts of largest Brazilian cities, as suggested by previous studies.

Use of a recombinant cysteine proteinase from Leishmania (Leishmania) infantum chagasi for the Immunotherapy of canine visceral Leishmaniasis

BACKGROUND

A recombinant cysteine proteinase from Leishmania (Leishmania) infantum chagasi (rLdccys1) was previously shown to induce protective immune responses against murine and canine visceral leishmaniasis. These findings encouraged us to use rLdccys1 in the immunotherapy of naturally infected dogs from Teresina, Piauí, a region of high incidence of visceral leishmaniasis in Brazil.

METHODOLOGY/PRINCIPAL FINDINGS

Thirty naturally infected mongrel dogs displaying clinical signs of visceral leishmaniasis were randomly divided in three groups: one group received three doses of rLdccys1 in combination with the adjuvant Propionibacterium acnes at one month interval between each dose; a second group received three doses of P. acnes alone; a third group received saline. The main findings were: 1) dogs that received rLdccys1 with P. acnes did not display increase of the following clinical signs: weight loss, alopecia, onychogryphosis, cachexia, anorexia, apathy, skin lesions, hyperkeratosis, ocular secretion, and enlarged lymph nodes; they also exhibited a significant reduction in the spleen parasite load in comparison to the control dogs; 2) rLdccys1-treated dogs exhibited a significant delayed type cutaneous hypersensitivity elicited by the recombinant antigen, as well as high IgG2 serum titers and low IgG1 serum titers; sera from rLdccys1-treated dogs also contained high IFN-γ and low IL-10 concentrations; 3) control dogs exhibited all of the clinical signs of visceral leishmaniasis and had low serum IgG2 and IFN-γ levels and high concentrations of IgG1 and IL-10; 4) all of the dogs treated with rLdccys1 were alive 12 months after treatment, whereas dogs which received either saline or P. acnes alone died within 3 to 7 months.

CONCLUSIONS/SIGNIFICANCE

These findings illustrate the potential use of rLdccys1 as an additional tool for the immunotherapy of canine visceral leishmaniasis and support further studies designed to improve the efficacy of this recombinant antigen for the treatment of this neglected disease.

Genotoxicity and antileishmanial activity evaluation of Physalis angulata concentrated ethanolic extract

Antileishmanial in vitro tests, as well as Ames and micronucleus assays were performed with a concentrated ethanolic extract of Physalis angulata (EEPA) RESULTS: EEPA did not present mutagenic effect in Salmonella typhimurium strains at concentration reaching 3000 μg/plate and did not induce mutagenic effects after two oral administrations with a 24h interval at a dose level of 2000 mg/kg. EEPA presented antileishmanial activity and presented an IC₅₀ value of 5.35 ± 2.50 μg/mL and 4.50 ± 1.17 μg/mL against Leishmania amazonensis and Leishmania braziliensis promastigotes, respectively. In the cytotoxicity test against macrophages, the EEPA had a LC₅₀ of 6.14 ± 0.59 μg/mL. Importantly, the IC₅₀ against L. amazonensis intracellular amastigotes was 1.23 ± 0.11 μg/mL.

CONCLUSION

EEPA extract is non-mutagenic and presented a promising pharmacological effect against Leishmania parasites.

Patterns of migration and risks associated with leprosy among migrants in Maranhão, Brazil

Leprosy remains a public health problem in Brazil with new case incidence exceeding World Health Organization (WHO) goals in endemic clusters throughout the country. Migration can facilitate movement of disease between endemic and non-endemic areas, and has been considered a possible factor in continued leprosy incidence in Brazil. A study was conducted to investigate migration as a risk factor for leprosy. The study had three aims: (1) examine past five year migration as a risk factor for leprosy, (2) describe and compare geographic and temporal patterns of migration among past 5-year migrants with leprosy and a control group, and (3) examine social determinants of health associated with leprosy among past 5-year migrants. The study implemented a matched case-control design and analysis comparing individuals newly diagnosed with leprosy (n = 340) and a clinically unapparent control group (n = 340) without clinical signs of leprosy, matched for age, sex and location in four endemic municipalities in the state of Maranhão, northeastern Brazil. Fishers exact test was used to conduct bivariate analyses. A multivariate logistic regression analysis was employed to control for possible confounding variables. Eighty cases (23.5%) migrated 5-years prior to diagnosis, and 55 controls (16.2%) migrated 5-years prior to the corresponding case diagnosis. Past 5 year migration was found to be associated with leprosy (OR: 1.59; 95% CI 1.07-2.38; p = 0.02), and remained significantly associated with leprosy after controlling for leprosy contact in the family, household, and family/household contact. Poverty, as well as leprosy contact in the family, household and other leprosy contact, was associated with leprosy among past 5-year migrants in the bivariate analysis. Alcohol consumption was also associated with leprosy, a relevant risk factor in susceptibility to infection that should be explored in future research. Our findings provide insight into patterns of migration to localize focused control efforts in endemic areas with high population mobility.

Adaptações crônicas sobre a função pulmonar em indivíduos infectados pela leishmaniose visceral

INTRODUÇÃO: Apesar de escassas, as principais alterações cardiopulmonares verificadas durante a infecção com Leishmaniose Visceral (LV) se referem a alterações histológicas e imunológicas e poucos relatos de repercussões funcionais. OBJETIVO: Verificar e analisar a existência de adaptações crônicas na função pulmonar de indivíduos assintomáticos previamente infectados pela LV. MATERIAIS E MÉTODOS: Trata-se de um estudo do tipo transversal descritivo, para o qual foram selecionados todos os indivíduos que contraíram LV em Parnaíba (Piauí, Brasil) entre 2007 e 2010 de acordo com informações do Setor de Epidemiologia do município. De um total de 20 indivíduos com confirmação parasitológica de LV, foram avaliados nove com idades entre 18 e 62 anos entre setembro e outubro de 2011. Excluíram-se indivíduos que não apresentaram diagnóstico parasitológico de LV, doenças ou sintomas cardiorrespiratórios recentes, usuários crônicos de drogas ilícitas e gestantes. Foram realizadas medidas antropométricas e testes de espirometria e de manovacuometria conforme especificações da American Thoracic Society / European Respiratory Society (ATS/ERS). Para comparação das médias dos valores medidos e preditos foi realizado Teste t Student para dados dependentes. O nível de significância adotado foi p < 0,05. RESULTADOS: A Capacidade Vital Forçada (CVF) (3,8 ± 0,9 vs. 4,2 ± 0,8 L) e o Volume Expiratório Forçado no primeiro segundo (VEF1) (3,3 ± 0,7 vs. 3,5 ± 0,7 L) foram estatisticamente menores do que os valores medidos (p < 0,01). A relação VEF1/CVF (87,6 vs. 84,4%) foi maior nos valores medidos (p = 0,08). CONCLUSÃO: Apesar de o número de indivíduos avaliados ser pequeno, os dados indicam que a infecção por LV parece desenvolver adaptações crônicas sobre o sistema respiratório, resultando em volumes pulmonares significativamente diminuídos e uma tendência a padrões respiratórios restritivos.