Leishmaniasis In Urban Area Research Articles

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).

Molecular detection of Leishmania infantum in rats and sand flies in the urban sewers of Barcelona, Spain

BackgroundClassically, dogs have been considered to be the only reservoir of leishmaniasis in urban areas. However, in a previous study, we found a 33.3% prevalence of Leishmania infantum in the spleens of Norway rats (Rattus norvegicus) sampled in the underground sewer system of the city of Barcelona (Spain). The aim of the present study was to verify, using molecular methods, the potential reservoir role of these rats in the same sewer system.MethodsA sensitive real-time PCR (qPCR) assay, DNA sequencing and phylogenetic analysis were carried out to identify and quantify the presence of L. infantum DNA in sand fly individuals captured in the same underground sewer system of Barcelona as in our previous study and in the spleens and ears of rats captured in the same sewer system.ResultsLeishmania infantum DNA was found in 14 of the 27 (51.9%) sand flies identified as Phlebotomus perniciosus, and 10 of the 24 (41.7%) rats studied were infected. Leishmania infantum was found in the spleens (70%) and in the ears (40%) of the infected rats. Quantitative results revealed the presence of high loads of L. infantum in the rats studied (> 3 × 106 parasites/g ear tissue) and among the sand flies (> 34 × 106 parasites in 1 individual).ConclusionsThe molecular methods used in this study demonstrated a high prevalence of L. infantum in the underground sewer populations of both R. norvegicus and P. perniciosus. These results suggest that sewer rats, in addition to dogs, are likely to act as reservoirs of leishmaniasis in cities, where sewer systems seem to offer the ideal scenario for the transmission of leishmaniasis. Therefore, to achieve the WHO 2030 target on the elimination of leishmaniasis as a public health problem successfully, an efficient control strategy against leishmaniasis in rats and sand flies should be implemented, particularly in the sewer systems of urban areas of endemic countries.Graphical

Leishmaniasis in non-human primates: Clinical and pathological manifestations and potential as reservoirs.

Although the domestic dog is the most important reservoir of visceral leishmaniasis in urban areas, there have been an increasing number of reports of naturally occurring leishmaniasis in non-human primates. Reported cases affecting neotropical and Old World non-human primates as well as their potential role as reservoirs were reviewed.

Avaliação da repelência de um medicamento à base de dinotefuran, permetrina e piriproxifen em cães exposto a infestações experimentais com flebotomíneos (Lutzomyia longipalpis)

Visceral leishmaniasis is a serious zoonosis, and has a high incidence in Brazil. The ubiquitous presence of sand flies is a major player in the high incidence of leishmaniasis in urban areas of Brazil. Prevention and control or canine leishmaniasis is important to decrease the incidence of the zoonosis. Control is done with topical use of products with antiparasitic, repellent and insecticide action. This study evaluated the repellent efficacy of line-on application of a topical permethrin-dinotefuran-pyriproxyfen formulation in dogs. Six dogs were treated with the product and six did not receive treatment. All dogs were sedated and exposed to sand flies of the species Lutzomyia longipalpis weekly for 28 days. The result showed that the product had an efficacy of 90.4% in repelling sand flies. There was statistical significance (p ≤ 0,05) difference in the number (mean) of live engorged sand fly females between the two groups in all evaluations. The product showed repellent efficacy against Lutzomyia longipalpis for 28 days.

Autochthonous Canine Visceral Leishmaniasis in Urban Area of Porto Alegre, RS, Brazil

Background: Leishmaniasis is a chronic infectious disease caused by intracellular protozoan Leishmania that affects canine and human. The visceral leishmaniasis (VL) is caused by the Leishmania donovani complex, in which canines are the main reservoir for human VL. In Southern Brazil, case reports of this disease have increased, especially when canines are infected in endemic areas in the country. Canines usually present a systemic disease, characterized by cutaneous lesions, weight loss, generalized lymphadenopathy, hepatomegaly and splenomegaly. This report aims to describe the clinicalpathological features of a case of autochthonous VL in a canine of an urban area of Porto Alegre.Case: A male, mixed breed, dog , 7 year-old, resident at the East Side of Porto Alegre, living together with two other canines, presented at clinical examination progressive weight loss, associated with hyporexia and hyperthermia, evolving to lateral recumbency, paralisys, and death. At necropsy, the dog was cachectic with diffusely pale mucosae. Gross findings included liver enlarged, with multifocal firm brownish areas, spleen enlarged, showing multifocal firm round dark-red areas, and kidneys diffusely pale with evidentiated tranversal striations on cortical zone. At microscopic examination, there was on the spleen diffuse inflammatory infiltrate of macrophages with large cytoplasm containing multiple amastigotes. The liver, exhibited atrophy of hepatocytes and moderate multifocal inflammatory infiltrate in sinusoids of macrophages containing multiple amastigotes. These features were also observed moderately on lymph nodes and lamina propria of large intestine. Immunohistochemistry examination showed marked positive staining for Leishmania spp. in amastigotes located whitin the cytoplasm of macrophages of spleen, liver, lymph nodes and large intestine.Discussion: Canine leishmaniasis is a disease that affects both internal organs and skin. However, the condition is called VL mostly because it is associated with the same species that cause the visceral form in humans. In this case the canine presented liver, spleen and lymph node lesions; however no skin lesion was observed during the clinical examination. A serological evaluation of canids in East Side of Porto Alegre performed in 2005 showed that 3.5% of these dogs were positive for Leishmania; yet neither of these animals presented clinical signs. This demonstrates that the agent was already present, however only 3-10% of the canines infected develop clinical disease. In non-endemic areas VL is related to the migration of canids from endemic areas, where VL is common. However the canine here described was born, raised, and was living in Porto Alegre. Lutzomyia longipalpis is the main vector of VL and despite its wide distribution it was identified only in 2009 in Rio Grande do Sul State. Autochthonous cases of VL were reported in canines and humans in this state, confirming the hypothesis that the vector was widely distributed and it is now present in Porto Alegre, keeping the epidemiological cycle of that disease active. Canine VL occurs prior in humans, since canines are the main domestic reservoirs and are critical for the maintenance of this disease cycle. This is the first autochthonous VL in a canine of an urban area of Porto Alegre; therefore authorities should be alert, and new control measures must be taken to avoid the canine leishmaniasis outbreak due to its potential for zoonotic transmission.Keywords: leishmaniasis, canine, protozoan, immunohistochemistry.

Mixed infection of Leishmania infantum and Leishmania braziliensis in rodents from endemic urban area of the New World.

BackgroundIn Brazil Leishmania braziliensis and L. infantum are the principal species responsible for cutaneous and visceral leishmaniases, respectively. Domestic dogs are the main reservoirs of visceral leishmaniasis, while rodents and marsupials are the main reservoirs for cutaneous leishmaniasis. It has also been suggested that dogs could play a role in transmission of cutaneous leishmaniasis. The identification of the species of Leishmania, the reservoirs, and the vectors involved in each particular transmission cycle is critical for the establishment of control activities. Belo Horizonte has emerged as an endemic region for leishmaniases, however, epidemiological studies assessing the contribution of wild reservoirs to transmission are scarce in the area. The aim of this study was to investigate Leishmania spp. infection in possible reservoirs of an urbanized area.ResultsA high rate of infection was found in small mammals (64.9%) and dogs (DG1 30.4% and DG2 48.6%). The presence of L. infantum and L. braziliensis was detected in small mammals and dogs, and mixed infections by both species were detected in rodents which, to the best of our knowledge, is the first description of this phenomenon in an urban area. Additionally, L. amazonensis was detected in the canine samples.ConclusionThe possible role of these animals as a source of infection of the vector of each species of Leishmania identified should not be overlooked and should be taken into account in future control activities. The results of mixed infection by L. braziliensis and L. infantum in cosmopolitan rodents as M. musculus and R. rattus, may have important implications in the context of the control of leishmaniasis in urban areas, especially when considering that these rodents live in close relationship with human dwellings, especially those in more precarious conditions.

Molecular and serological detection of Leishmania spp. in captive wild animals from Ilha Solteira, SP, Brazil

Leishmaniasis is a zoonotic disease that affects 12 million people worldwide. Several mammalian species can serve as a reservoir for this disease. Dogs are the main reservoir for visceral leishmaniasis in urban areas, which has become a serious public health concern in Brazil. The aim of this study was to evaluate the presence of Leishmania spp. in captive wild animals from Ilha Solteira, São Paulo, Brazil. Blood and various tissues samples were collected from animals of five different species: Speothos venaticus, Chrysocyon brachyurus, Cerdocyon thous, Pseudalopex vetulus, and Procyon cancrivorus. Antibodies against Leishmania spp. were detected in three wild canids by indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). PCR analyses of blood and bone marrow from all animals were negative, but Leishmania DNA was found in the tissues and skin of seropositive animals. Positive PCR samples were also positive for Leishmania donovani complex. Analysis of sequenced PCR products showed similarities with different regions of Leishmania (Leishmania) infantum and Leishmania (Leishmania) chagasi kinetoplastids. Measures to control visceral leishmaniasis in wild animals kept in Brazilian zoos should be established, as no disease control programs are currently available.

Análise histomorfométrica da matriz extracelular do linfonodo poplíteo de cães naturalmente infectados por Leishmania (L.) chagasi

Nas Américas, a leishmaniose visceral canina é causada por Leishmania (Leishmania) chagasi, um protozoário intracelular obrigatório do sistema fagocítico mononuclear; as principais alterações histológicas associadas a essa doença ocorrem nos em órgãos linfóides. Apesar de o cão ser considerado o principal mantenedor e disseminador da leishmaniose no ambiente urbano, são escassos estudos dos aspectos histopatológicos e histomorfométricos, em cães naturalmente infectados com L. chagasi, que investiguem a interação entre o parasito e a matriz extracelular. Este estudo visou caracterizar e quantificar as alterações dos componentes celulares e da matriz extracelular (colágenos I e III) do linfonodo poplíteo de 22 cães com infecção natural por L. chagasi detectada através da reação de imunofluorescência indireta (RIF) e compará-las com as alterações encontradas no linfonodo poplíteo de 10 cães não-infectados, negativos na RIF e clinicamente saudáveis. Fragmentos dos linfonodos foram seccionados longitudinalmente, processados rotineiramente para exame histológico e corados por hematoxilina-eosina. Cortes adicionais do mesmo linfonodo incluídos em glicol metacrilato foram corados pelo azul de toluidina para histomorfometria. Linfonodos de cães infectados apresentaram linfadenopatia generalizada, aumento do tamanho e do número dos folículos linfóides, hipertrofia da cápsula e hiperplasia linfóide significativa. Nos linfonodos de cães do grupo infectado, a análise quantitativa de fibras colágenas mostrou significativo predomínio do colágeno I sobre o colágeno III. Esses resultados demonstram que cães infectados por L. chagasi apresentam degradação dos constituintes da matriz extracelular e conseqüente destruição do arcabouço linfóide, alterando a morfologia do órgão.

Visceral leishmaniasis in large Brazilian cities: challenges for control

The objectives of this article were to discuss the rapid spread of visceral leishmaniasis in urban areas of Brazil and to raise practical questions and perspectives related to control of the disease. Among the proposed methods, the elimination of seropositive dogs is the most controversial and least accepted by society. Its impact on incidence rates varies among studies (positive in some and relatively unimportant in others). Treatment of infected dogs, although widespread in veterinary practice, is based on studies with weak scientific evidence. Insecticide spraying of areas is more acceptable to the population, but is costly and operationally difficult. Intra and inter-urban factors have scarcely been studied and may affect control of the disease. Finally, the article discusses the use of deltamethrin-impregnated dog collars and vaccines, with high expectations for impact on disease transmission, although no product currently available on the market has been fully evaluated, so that further studies are required.

Forum: geographic spread and urbanization of visceral leishmaniasis in Brazil. Introduction

The geographic spread and urbanization of visceral leishmaniasis in Brazil has been described since the early 1980s. However, the putative factors associated with this process, its full characterization, and the implications for disease control still challenge researchers and Public Health professionals. Although the available data show that the disease occurs mainly in urban areas, current knowledge is insufficient to claim specificity in urban transmission as compared to rural niches. Transmission scenarios in urban settings appear to be highly heterogeneous, each showing some degree of similarity to the rural epidemiological pattern. The understanding of a relatively recent and complex problem like the introduction, spread, and maintenance of visceral leishmaniasis in urban areas requires new analytical approaches that consider the network of relevant variables and more elaborate methods capable of capturing the dynamics of the environmental and demographic transformations taking place in transmission areas.

Diagnóstico de leishmaniose canina na área urbana do município de Cuiabá, Estado de Mato Grosso, Brasil

An investigation was carried out to determine the occurrence of cutaneous and visceral leishmaniasis in the urban canine population of the District of Cuiaba, State of Mato Grosso. In the period from August of 1997 to July of 1998 blood samples of 800 dogs were collected, from different neighborhoods of Cuiaba, chosen at random and sent to the Service of Parasitology of the Municipal Institute of Veterinary Medicine Jorge Vaitsman, in Rio de Janeiro, for examination by the indirect immunofluorescent test. At the beginning 62 serum samples were processed, from which 64.5% (40 samples) were positive for leishmaniasis. In relation to the titters found in the reacting serum, 92.5% (37 samples) presented titters above 1:160, what suggests strong suspicion of the presence of visceral leishmaniasis. From this total, 72.5% (29 samples) of the positive serum came from dogs of the South-East region and 27.5% (11 samples) of the Center-East region of Cuiaba. This is the first report of the detection of serum positive dogs for leishmaniasis in urban area of the State of Mato Grosso.