Trypanosoma cruzi genetic diversity: impact on transmission cycles and Chagas disease

Trypanosoma cruzi, the agent of Chagas disease (ChD), exhibits remarkable biological and genetic diversity, along with eco-epidemiological complexity. In order to facilitate communication among researchers aiming at the characterisation of biological and epidemiological aspects of T. cruzi, parasite isolates and strains were partitioned into seven discrete typing units (DTUs), TcI-TcVI and TcBat, identifiable by reproducible genotyping protocols. Here we present the potential origin of the genetic diversity of T. cruzi and summarise knowledge about eco-epidemiological associations of DTUs with mammalian reservoirs and vectors. Circumstantial evidence of a connection between T. cruzi genotype and ChD manifestations is also discussed emphasising the role of the host's immune response in clinical ChD progression. We describe genomic aspects of DTUs focusing on polymorphisms in multigene families encoding surface antigens that play essential functions for parasite survival both in the insect vector and the mammalian host. Such antigens most probably contributed to the parasite success in establishing infections in different hosts and exploring several niches. Gaps in the current knowledge and challenges for future research are pointed out.

Study on the zoonotic cycle of tegumentary leishmaniasis in an endemic area of a metropolitan region in the Northeastern region of Brazil

ABSTRACT This study was conducted to characterize the transmission cycle of the tegumentary leishmaniasis (TL) in an old colonization area at Pernambuco State, Brazil. The aims were to identify autochthonous cases, sandflies fauna, domestic animals as possible reservoir hosts and the Leishmania species involved in this endemic area. A total of 168 suspected human cases of TL and 272 domestic animals (canine, feline, equine, goat, and sheep) were included. The sandflies were captured and identified by species. Patients were predominantly male and the average age was 37+18.1 years old. Of 85 patients who had skin lesions, 25.6% of them had direct positive smears for TL and 34 isolates were identified as Leishmania (Viannia) braziliensis. The confirmation for TL diagnosed by molecular detection (PCR) was almost three times more sensitive than the direct test [p < 0.001; PR = 2.72] associated with clinical examination. The Kappa test on PCR between two different specimens, biopsy, and skin lesion swab was 60.8% (p < 0.001). More than 200 specimens of sandflies (80 males and 159 females) were captured and identified as Lutzomyia whitmani (99.6%) and Lu. evandroi (0.4%). The detection of L. (V.) braziliensis by Real-Time PCR in the blood of a captured fed female was positive in 59.3% of Lu. whitmani. Of the 272 domestic animals included, 61.76% were male (n = 168). Thirty-six animals (13.2%) had lesions compatible with TL (34 dogs, 1 cat and 1 sheep) and 3 of them, all dogs, had lesions on the snout, showing destruction of cartilage and mucosa. The study suggests the participation of domestic animals as possible reservoirs. However, further studies are necessary to better understand the transmission cycle and take recommended measures in order to control the disease.

Addressing the recent dispersion of urban visceral leishmaniasis in the border of Argentina, Brazil, Paraguay + Uruguay + Bolivia – Project IDRC / Abordando a recente dispersão da leishmaniose visceral urbana nas fronteiras da Argentina, Brasil e Paraguai + Uruguai + Bolívia - Projeto IDRC

The territory located in the border of Argentina, Brazil and Paraguay is endemic for tegumentary leishmaniasis (TL). However, Lutzomyia longipalpis first report in the area was in 2010-Argentina, in 2012-Brazil, and no records in the Paraguayan border despite of reports of human visceral leishmaniasis (VL) cases. Therefore, we developed a research from 2014 to 2017 to study VL in the three-country border at locality level; Uruguay-2015, and Bolivia-2016 joined latter due to the alerts of VL in the Argentinean borders. The space-time distributions of vectors, infected dogs and environmental variables were recorded and associated at three progressive scales, while anthropological surveys were performed. Three scenarios were characterized based on canine VL prevalence, vector presence-abundance and the spatial distribution consistency between them: settled VL, incipient VL, and steady TL with imported canine VL. The vector abundance was clustered in ‘hot spots’ persistent in time that could act as ‘source populations’. The clustering distribution was associated with environmental variables at the different scales studied. Therefore, the vector distribution (proxy of human-dog exposure) could be modeled in recent southern scenarios to focus the surveillance and interventions on predicted ‘hot spots’, in order to increase the effectiveness and efficiency of program activities.

O território localizado na fronteira da Argentina, Brasil e Paraguai é endêmico para leishmaniose tegumentar (LT). Entretanto, o primeiro relato de Lutzomyia longipalpis na área foi em 2010-Argentina, em 2012-Brasil, sem registros na fronteira em Paraguai apesar dos casos de leishmaniose visceral humana (LV). Portanto, desenvolvemos uma pesquisa de 2014 a 2017 para estudar a LV na tríplice fronteira em nível de localidades; Uruguai-2015 e Bolívia-2016 aderiram mais tarde devido aos alertas de LV nas fronteiras argentinas. As distribuições espaço-temporais de vetores, cães infectados e as variáveis ambientais foram registradas e associadas em três escalas progressivas, enquanto se realizou o inquérito antropológico. Três cenários foram caracterizados com base na prevalência de LV canina, na abundância-presença de vetores, e a coerência da distribuição espacial entre eles: LV instalada, LV incipiente e LT estável com LV canina importada. A abundância de vetores foi agrupada em “pontos quentes” persistentes no tempo que poderiam atuar como “populações fonte”. A distribuição de agrupamento foi associada a variáveis ambientais nas diferentes escalas. Portanto, a distribuição vetorial (proxy da exposição humana a cães) poderia ser modelada em cenários recentes do sul para focar a vigilância e as intervenções nos “pontos quentes” previstos, a fim de aumentar a eficácia e a eficiência das atividades do programa.

Addressing the recent dispersion of urban visceral leishmaniasis in the border of Argentina, Brazil, Paraguay + Uruguay + Bolivia ­ Project IDRC

The territory located in the border of Argentina, Brazil and Paraguay is endemic for tegumentary leishmaniasis (TL). However, Lutzomyia longipalpis first report in the area was in 2010-Argentina, in 2012-Brazil, and no records in the Paraguayan border despite of reports of human visceral leishmaniasis (VL) cases. Therefore, we developed a research from 2014 to 2017 to study VL in the three-country border at locality level; Uruguay-2015, and Bolivia-2016 joined latter due to the alerts of VL in the Argentinean borders. The space-time distributions of vectors, infected dogs and environmental variables were recorded and associated at three progressive scales, while anthropological surveys were performed. Three scenarios were characterized based on canine VL prevalence, vector presence-abundance and the spatial distribution consistency between them: settled VL, incipient VL, and steady TL with imported canine VL. The vector abundance was clustered in 'hot spots' persistent in time that could act as 'source populations'. The clustering distribution was associated with environmental variables at the different scales studied. Therefore, the vector distribution (proxy of human-dog exposure) could be modeled in recent southern scenarios to focus the surveillance and interventions on predicted 'hot spots', in order to increase the effectiveness and efficiency of program activities. (AU)

O território localizado na fronteira da Argentina, Brasil e Paraguai é endêmico para leishmaniose tegumentar (LT). Entretanto, o primeiro relato de Lutzomyia longipalpis na área foi em 2010-Argentina, em 2012-Brasil, sem registros na fronteira em Paraguai apesar dos casos de leishmaniose visceral humana (LV). Portanto, desenvolvemos uma pesquisa de 2014 a 2017 para estudar a LV na tríplice fronteira em nível de localidades; Uruguai-2015 e Bolívia-2016 aderiram mais tarde devido aos alertas de LV nas fronteiras argentinas. As distribuições espaço-temporais de vetores, cães infectados e as variáveis ambientais foram registradas e associadas em três escalas progressivas, enquanto se realizou o inquérito antropológico. Três cenários foram caracterizados com base na prevalência de LV canina, na abundância-presença de vetores, e a coerência da distribuição espacial entre eles: LV instalada, LV incipiente e LT estável com LV canina importada. A abundância de vetores foi agrupada em "pontos quentes" persistentes no tempo que poderiam atuar como "populações fonte". A distribuição de agrupamento foi associada a variáveis ambientais nas diferentes escalas. Portanto, a distribuição vetorial (proxy da exposição humana a cães) poderia ser modelada em cenários recentes do sul para focar a vigilância e as intervenções nos "pontos quentes" previstos, a fim de aumentar a eficácia e a eficiência das atividades do programa. (AU)

Human leptospirosis in the Federal District, Brazil, 2011-2015: eco-epidemiological characterization

Abstract INTRODUCTION: Leptospirosis is an infectious disease that affects more than 5,000 people per year in Brazil. The Federal District (FD) lacks epidemiological studies of human leptospirosis and presents concerning rates of this disease, especially considering its lethality. METHODS: Seventy-nine autochthonous human cases of leptospirosis between 2011 and 2015 were analyzed, with the probable infection location serving as a basis for the collection and analysis of the environmental and epidemiological variables. RESULTS: The incidence of the disease ranged from 0.68-13.39 per 100,000 inhabitants in 21 of the 31 administrative regions that compose the FD. The local profile of human leptospirosis was predominantly associated with urban areas during the rainy season, population access to the sewage network, the treated water network, and the public garbage collection service. The vast majority of cases had a strong association with synanthropic rodents at the infection sites. CONCLUSIONS: In order to prevent and control potentially lethal human leptospirosis infection, the eco-epidemiological characterization of this disease is a valuable tool for public policies of prevention, control, and surveillance. In addition to population awareness, the systematized control of synanthropic rodents could be the main health action to reduce the incidence of this disease in the FD.

The eco-epidemiology of Triatoma infestans in the temperate Monte Desert ecoregion of mid-western Argentina

BACKGROUND The eco-epidemiological status of Chagas disease in the Monte Desert ecoregion of western Argentina is largely unknown. We investigated the environmental and socio-demographic determinants of house infestation with Triatoma infestans, bug abundance, vector infection with Trypanosoma cruzi and host-feeding sources in a well-defined rural area of Lavalle Department in the Mendoza province. METHODS Technical personnel inspected 198 houses for evidence of infestation with T. infestans, and the 76 houses included in the current study were re-inspected. In parallel with the vector survey, an environmental and socio-demographic survey was also conducted. Univariate risk factor analysis for domiciliary infestation was carried out using Firth penalised logistic regression. We fitted generalised linear models for house infestation and bug abundance. Blood meals were tested with a direct ELISA assay, and T. cruzi infection was determined using a hot-start polymerase chain reaction (PCR) targeting the kinetoplast minicircle (kDNA-PCR). FINDINGS The households studied included an aged population living in precarious houses whose main economic activities included goat husbandry. T. infestans was found in 21.2% of 198 houses and in 55.3% of the 76 re-inspected houses. Peridomestic habitats exhibited higher infestation rates and bug abundances than did domiciles, and goat corrals showed high levels of infestation. The main host-feeding sources were goats. Vector infection was present in 10.2% of domiciles and 3.2% of peridomiciles. Generalised linear models showed that peridomestic infestation was positively and significantly associated with the presence of mud walls and the abundance of chickens and goats, and bug abundance increased with the number of all hosts except rabbits. MAIN CONCLUSIONS We highlight the relative importance of specific peridomestic structures (i.e., goat corrals and chicken coops) associated with construction materials and host abundance as sources of persistent bug infestation driving domestic colonisation. Environmental management strategies framed in a community-based programme combined with improved insecticide spraying and sustained vector surveillance are needed to effectively suppress local T. infestans populations.

Mycobacterium leprae in six-banded (Euphractus sexcinctus) and nine-banded armadillos (Dasypus novemcinctus) in Northeast Brazil

Human beings are the main reservoir of the causative agent of leprosy, Mycobacterium leprae. In the Americas, nine-banded armadillos (Dasypus novemcinctus) also act as a reservoir for the bacillus. In the state of Ceará (CE), which is located in Northeast Brazil and is an endemic area of leprosy, there are several species of armadillos, including D. novemcinctus and Euphractus sexcinctus (six-banded armadillo). Contact between humans and armadillos occur mainly through hunting, cleaning, preparing, cooking and eating. This study identified M. leprae DNA in the two main species of armadillos found in Northeast Brazil. A total of 29 wild armadillos (27 D. novemcinctus and 2 E. sexcinctus) were captured in different environments of CE countryside. Samples from the ear, nose, liver and spleen from each of these animals were tested by a nested M. leprae-specific repetitive element polymerase chain reaction assay. The samples that tested positive were confirmed by DNA sequencing. M. leprae was detected in 21% (6/29) of the animals, including five D. novemcinctus and one E. sexcinctus. This is the first Brazilian study to identify the presence of a biomarker of M. leprae in wild armadillos (D. novemcinctus and E. sexcinctus) in a leprosy hyperendemic area where there is continuous contact between humans and armadillos.

Ecología de la coccidioidomicosis en el municipio Falcón de la Península de Paraguaná, estado Falcón, Venezuela / Ecology of coccidioidomycosis at the Falcon municipality of Paraguana Peninsula, Falcon State, Venezuela

Se estudiaron las características ecoambientales de poblaciones del municipio Falcón de la Península de Paraguaná, y se cultivaron muestras de suelo para identificación de los aislados sugestivos de Coccidioides spp., mediante examen directo de las muestras de tejido de ratones inoculados con el hongo. Las características ecoambientales del municipio y el análisis químico del suelo favorecen la presencia del hongo en esta zona. Del cultivo de suelos se obtuvo un aislado sugestivo de Coccidioides spp., pero el estudio en animales de experimentación no reveló la formación de esférulas. Se confirmó la existencia de un área de riesgo para la coccidioidomicosis en la Península de Paraguaná.

The eco-environmental characteristics of populations from the Falcon Municipality of the Paraguana Peninsula were studied, and soil samples were taken for identification of isolates suggestive of Coccidioides spp., through direct exam of tissue samples from mice infected with this fungus. The eco-environmental characteristics of the municipality and the chemical analysis of the soil favor the presence of this fungus in this zone. From the soil sample cultures we obtained an isolate suggestive of Coccidioides spp, but the experimental animal study did not reveal spherule formation. The existence of a Coccidioidomycosis risk area at the Paraguana Peninsula was confirmed.

Search for Mycobacterium leprae in wild mammals

Leprosy is still a worldwide public health problem. Brazil and India show the highest prevalence rates of the disease. Natural infection of armadillos Dasypus novemcinctus with Mycobacterium leprae has been reported in some regions of the United States. Identification of bacilli is difficult, particularly due to its inability to grow in vitro. The use of molecular tools represents a fast and sensitive alternative method for diagnosis of mycobacteriosis. In the present study, the diagnostic methods used were bacilloscopy, histopathology, microbiology, and PCR using specific primers for M. leprae repetitive sequences. PCR were performed using genomic DNA extracted from 138 samples of liver, spleen, lymph nodes, and skin of 44 D. novemcinctus, Euphractus sexcinctus, Cabassous unicinctus, and C. tatouay armadillos from the Middle Western region of the state of São Paulo and from the experimental station of Embrapa Pantanal, located in Pantanal da Nhecolândia of Mato Grosso do Sul state. Also, the molecular analysis of 19 samples from internal organs of other road killed species of wild animals, such as Nasua nasua (ring-tailed coati), Procyon cancrivoros (hand-skinned), Cerdocyon thous (dog-pity-bush), Cavia aperea (restless cavy), Didelphis albiventris (skunk), Sphigurrus spinosus (hedgehog), and Gallictis vittata (ferret) showed PCR negative data. None of the 157 analyzed samples had shown natural mycobacterial infection. Only the armadillo inoculated with material collected from untreated multibacillary leprosy patient presented PCR positive and its genomic sequencing revealed 100 percent identity with M. leprae. According to these preliminary studies, based on the used methodology, it is possible to conclude that wild mammals seem not to play an important role in the epidemiology of leprosy in the Middle Western region of the São Paulo state and in the Pantanal of Mato Grosso do Sul state.

Road-killed wild animals: a preservation problem useful for eco-epidemiological studies of pathogens

Road-killed wild animals have been for years used for surveillance of vectors of zoonotic pathogens and may offer new opportunities for eco-epidemiological studies. In the current study, fungal infection was evaluated by PCR and nested-PCR in tissue samples collected from 19 road-killed wild animals. The necropsies were carried out and samples were collected for DNA extraction. Results, using PCR with a panfungal primer and nested PCR with specific primers, indicated that some animals are naturally infected with Amauroascus aureus, Metarhizium anisopliae, Aspergillus flavus, Aspergillus oryzae, Emmonsia parva, Paracoccidioides brasiliensis or Pichia stipitis. The approach employed herein proved useful for detecting the environmental occurrence of several fungi, as well as determining natural reservoirs in wild animals and facilitating the understanding of host-pathogen relationships.

Visceral leishmaniasis in Rio de Janeiro, Brazil: eco-epidemiological aspects and control / Leishmaniose visceral no Rio de Janeiro, Brasil: aspectos eco-epidemiológicos e controle

From 1977 (index case) to 2006, 87 cases of visceral leishmaniasis were confirmed in the municipality of Rio de Janeiro, Brazil, in periurban areas on the continental and coastal slopes of the Pedra Branca massif and the continental slopes of the Gericinó massif. The majority (65.5 percent) of the patients were more than five years old, predominantly males (61.5 percent), but without any difference between the sexes below the age of 14 years. The overall fatality rate was 10.4 percent. Two cases of visceral leishmaniasis/human immunodeficiency virus coinfection were detected. Leishmania chagasi was isolated from human and canine cases. The associations between the presence of phlebotomines and human and canine migrations, disorderly occupation involving degradation of environmental preservation areas and poor socioeconomic conditions may have created a favorable setting for the establishment and propagation of the disease. Close epidemiological surveillance associated with traditional control measures and others (active case researches, land clearing and health education), reduced the incidence of human cases from 2.8 per 100,000 inhabitants in 1981 to less than 0.01 per 100,000 since 1997. The canine infection rates decreased from 4.6 percent in 1984 to 1.6 percent in 2008. Lutzomyia longipalpis was not detected in some locations where human and canine cases occurred. In the years 2007 and 2008, no new human cases were reported, but there is a persistent and worrisome residual canine seroprevalence.

Entre 1977 (caso índice) e 2006 foram confirmados 87 casos de leishmaniose visceral no Município do Rio de Janeiro, oriundos de áreas peri-urbanas das vertentes continentais e litorâneas do Maciço da Pedra Branca e das vertentes continentais do Maciço do Gericinó. A maioria (65,5 por cento) dos pacientes tinha mais de 5 anos de idade, prevalecendo o sexo masculino (61,5 por cento), sem diferença de freqüência entre os sexos até os 14 anos. A letalidade foi de 10,4 por cento. Houve dois casos de co-infecção por leishmaniose visceral/vírus da imunodeficiência. Leishmania chagasi foi isolada de casos humanos e caninos. Presença de flebotomíneos associada a migrações humanas e caninas, ocupação desordenada degradando áreas de preservação ambiental e baixas condições socioeconômicas podem ter criado o contexto propício à instalação e à propagação da endemia. Vigilância epidemiológica estreita com as medidas tradicionais de controle e outras - busca ativa de pacientes, limpeza de terrenos e educação em saúde -, reduziram a incidência de casos humanos de 2,8 por 100 mil habitantes em 1981 para menos de 0,01 por 100 mil a partir de 1997. As taxas de infecção canina decresceram de 4,6 por cento em 1984 para 1,6 por cento em 2008. Lutzomyia longipalpis não foi detectada em algumas localidades onde ocorreram casos humanos e caninos. Em 2007 e 2008, nenhum novo caso da doença humana foi notificado, mas permanece uma preocupante prevalência sorológica residual canina.

Novo surto de leishmaniose tegumentar americana em área de treinamento militar na Zona da Mata norte do Estado de Pernambuco / New outbreak of American tegumentary leishmaniasis in a military training center in the Zona da Mata region, in the north of the State of Pernambuco

Relata-se novo surto de LTA em militares com 71 casos confirmados pelos critérios clínico, epidemiológico e laboratorial. Obteve-se o isolamento de sete amostras, identificadas como Leishmania (Viannia) braziliensis. A ocorrência de surtos nesta região confirma o caráter endêmico, cuja magnitude parece estar relacionada a não adoção de medidas de proteção individual.

A new outbreak of American tegumentary leishmaniasis among military personnel is reported, with 71 cases confirmed by means of clinical, epidemiological and laboratory criteria. Seven samples were isolated and were identified as Leishmania (Viannia) braziliensis. The occurrence of outbreaks in this region confirms the endemic nature of this disease, and the magnitude of the occurrence seems to be related to non-adoption of individual protection measures.

Molecular approaches for eco-epidemiological studies of Paracoccidioides brasiliensis

Medical mycology has greatly benefited from the introduction of molecular techniques. New knowledge on molecular genetics has provided both theoretical and practical frameworks, permitting important advances in our understanding of several aspects of pathogenic fungi. Considering Paracoccidioides brasiliensis in particular, important eco-epidemiological aspects, such as environmental distribution and new hosts were clarified through molecular approaches. These methodologies also contributed to a better understanding about the genetic variability of this pathogen; thus, P. brasiliensis is now assumed to represent a species complex. The present review focuses on some recent findings about the current taxonomic status of P. brasiliensis, its phylogenetic and speciation processes, as well as on some practical applications for the molecular detection of this pathogen in environmental and clinical materials.

Study on The Eco-epidemiology of Chikungunya in U T of Lakshadweep.

An unusual increase in the incidence of viral fever was noticed in Androth and Kalpeni Island, U.T of Lakshadweep during November 2006. The Ecoepidemiology of the disease was studied in detail. The study indicated that Aedes albopictus is the predominant species (98.74%) and it exhibited a wide spectrum of breeding preferences with a clear-cut predilection for rat-damaged coconuts (RDCs). All the entomological indices were very high in both the Islands with a marked increase in Kalpeni Island. The clinical presentation of the cases was typical of chikungunya and the laboratory study confirmed this. Based on the investigation, control and preventive measures were planned, advised and implemented. The details regarding the bio-ecology of vectors, clinical presentation, laboratory investigations and effectiveness of control measures are discussed.

Phlebotominae distribution in Janaúba, an area of transmission for visceral leishmaniasis in Brazil

In Brazil, visceral leishmaniasis (VL) is caused by Leishmania chagasi parasites that are transmitted to man through the bites of infected females of Lutzomyia longipalpis sand flies. In order to evaluate transmission risk and to clarify the epidemiology of this tropical disease, studies focused on the vector and favorable environmental conditions are of fundamental importance. In this work, we surveyed the phlebotomine sand fly fauna in Janaúba, a Brazilian municipality that is endemic for VL. During a two-year period, entomological captures were performed monthly in 15 districts with high, moderate and low profiles of VL transmission. A total of 14,591 phlebotomine sand flies were captured (92 percent L. longipalpis), with a predominance of males. Most specimens were captured in the peri-domicile setting, although the number of specimens captured in the intra-domicile setting emphasises the anthropophilic behaviour of this insect. The population density of L. longipalpis was modulated by climate variations, particularly with clear increases immediately after the rainy season. However, the pattern of distribution did not coincide with the occurrence of human or canine cases of VL. This suggests that the eco-epidemiology of VL is particular to each area of transmission and must be taken into account during the design of public health control actions.