Factores de riesgo para la transmisión de leishmaniasis cutánea en niños de 0 a 5 años en un área endémica de Leishmania (Viannia) braziliensis

Anthropogenic Dispersal of Leishmania (Viannia) braziliensis in the Americas: A Plausible Hypothesis

There are several gaps in our knowledge on the origin and spread of Leishmania (Viannia) braziliensis, an etiological agent of cutaneous and mucocutaneous or American tegumentary leishmaniasis, to different biomes, hosts, and vectors, with important epidemiological implications, including the possible existence of an anthroponotic component. Historical, biological, and epidemiological evidence suggests that Leishmania (V.) braziliensis and its variants were preexistent in Amazonia with great genetic variability, where they dispersed with less variability to other regions (clonal expansion). During pre-Columbian times the parasite may have been transported by migrating humans and probably also their dogs, from western Amazonia to the high inter-Andean valleys and from there to other regions of South America. The same thing could have happened later, in the same way, when it spread to non-Amazonian regions of Brazil and other countries of South and Central America, between the late 19th and early 20th centuries, during the so-called Rubber Boom and construction of the Madeira-Mamoré Railway in the Brazilian Amazon, by migrant workers who later returned to their places of origin, transporting the agent. The parasite’s dispersal in genetic correlated clusters, involving unexpectedly distinct ecosystems in Brazil (Amazonian, Cerrado, Caatinga and Atlantic Forest biomes), has continued until the present through human displacement. The infection of certain species of domestic, synanthropic and even wild animals, could be secondary to anthropogenic introduction of L. (V.) braziliensis in new environments. We admit the same phenomena happening in the probable transference of Leishmania infantum (visceral leishmaniasis), and of Yersinia pestis (plague) from the Old world to the New world, generating domestic and wild enzotic cycles from these agents. These assumptions associated with human infections, chronicity and parasite persistence with possibility of recovery of Leishmania in peripheral blood, skin and scars of cured or asymptomatic patients, (that may provide an alternative blood meal), along with the sand flies’ adaptation to the peri-domicile and the high susceptibility of domestic dogs, horses, mules and cats to the parasite, can reinforce the evidence of anthropogenic spread of L. (V.) braziliensis.

Leishmania naiffi and lainsoni in French Guiana: Clinical features and phylogenetic variability

In French Guiana, five species are associated with Cutaneous Leishmaniasis (CL). Though infections with Leishmania guyanensis, L. (V.) braziliensis and L. (L.) amazonensis have been extensively described, there are few available clinical and genetic data on L. (V.) lainsoni and L. (V.) naiffi. We determined the clinical and epidemiological features of all cases of CL due to L. (V.) naiffi and L. (V.) lainsoni diagnosed in French Guiana between 2003 and 2019. Phylogenetic analysis was performed by sequencing a portion of HSP70 and cyt b genes. Five cases of L. naiffi and 25 cases of L. lainsoni were reported. Patients infected by L. (V.) lainsoni were usually infected on gold camps, mostly along the Maroni river (60%), while L. naiffi was observed in French patients infected on the coast (100%). A high number of pediatric cases (n = 5; 20%) was observed for L. (V.) lainsoni. A mild clinical course was observed for all cases of L. (V.) naiffi. HSP70 and cyt b partial nucleotide sequence analysis revealed different geographical clusters within L. (V.) naiffi and L. (V.) lainsoni but no association were found between phylogenetic and clinical features. Our data suggest distinct socio-epidemiological features for these two Leishmania species. Patients seem to get infected with L. (V.) naiffi during leisure activities in anthropized coastal areas, while L. (V.) lainsoni shares common features with L. (V.) guyanensis and braziliensis and seems to be acquired during professional activities in primary forest regions. Phylogenetic analysis has provided information on the intraspecific genetic variability of L. (V.) naiffi and L. (V.) lainsoni and how these genotypes are distributed at the geographic level.

Land use in relation to composition and abundance of phlebotomines (Diptera: Psychodidae) in five foci of domiciliary transmission of cutaneous leishmaniasis in the Andean region of Colombia

American cutaneous leishmaniasis is a public health concern in Colombia, its incidence being sustained or focally increased principally by the emergence of domestic transmission concomitantly with the adaptation of the phlebotomine vectors to habitat transformation around households. The objective of the study is to scale up a rapid characterization methodology for evaluating the relationship of land use around the house to the composition and abundance of phlebotomines. Five sites with a history of domestic leishmaniasis transmission in the Andean area of Colombia were selected. The peri-domestic habitat was evaluated at 10 m intervals along eight radial transects, centered on each house, at 45° intervals using a web pattern. Phlebotomines were captured by placing three CDC light traps over two nights both indoors and outdoors (10 m from the house). Blood source and infection were determined by PCR. Spearman rank correlation coefficients and negative binomial regression were used to quantify associations between the phlebotomine abundance and habitat categories. The study demonstrated that the vectors were largely anthropophagic (62% of 79 were human blood) and that a single species in each site was favored by the pertaining agriculture monoculture. Specifically, Pintomyia (Pifanomyia) quasitownsendi was associated with sugar cane in Novillero and La Esmeralda; while Pi. (Pif.) longiflocosa was associated with coffee plantations in Agua Bonita and El Cucal. Honda Alta had a more diverse array of land use and forest coverage with a lower number of specimens but higher species diversity. In terms of distance from the house to an area of a given land use, the abundance of Pi. (Pif.) quasitownsendi was inversely related to the distance to sugar cane plantation (Spearman correlation coefficient, ρ = -0.56, p < 0.001 for outdoor catches, and ρ = -0.50, p < 0.001 indoors). A similar inverse relationship was observed for Pi. (Pif.) longiflocosa with regard to technified coffee (ρ = -0.51, p < 0.001 outdoors, and ρ = -0.48, p < 0.001 indoors). This rapid characterization methodology could guide public heath decision makers in identifying those houses at higher risk of domestic transmission, and also educate farmers to increase the distance between their crops and any neighboring houses.

Socioenvironmental aspects of the Purus Region - Brazilian Amazon: Why relate them to the occurrence of American Tegumentary Leishmaniasis?

This study aims to analyze factors related to the occurrence of American Tegumentary Leishmaniasis in the Purus Region, based on the reporting of cases between 2001 and 2013, correlating them with livelihoods and subsistence farming in the region, and analyzing them in regards to sex, age, clinical form, occupation, diagnostic methods and seasonality. The analysis parameter which was used included all cases of American Tegumentary Leishmaniasis in each sub-region by municipality. The Purus Region, between the states of Amazonas and Acre, consists of three sub-regions: Upper, Middle, and Lower Purus. We observed that socio-environmental impacts influenced the livelihoods of the human population and that the interaction with extractive activities, especially latex and Brazil nut collecting, where the labor regime implies a long stay in the jungle, leads to socio-environmental conditions that are favorable to the contraction of American Tegumentary Leishmaniasis. During the referred period, there were 13,971 cases of American Tegumentary Leishmaniasis distributed among the sub-regions: High (12611 cases = 90.27%), Middle (1225 cases = 8.77%) and Lower (135 cases = 0.96%). Among the 22 municipalities that were studied, Rio Branco stands out with 31.6% of cases, followed by Xapuri with 12.6% and Sena Madureira with 12.5%. In the results, we highlight the high percentage (20.8%) of mucous forms; the age group from 11 to 50 (70.2%), however, 20.2% were in the age group of 1 month to 10 years of age; cases in males were 69.8%, and, in the reports examined, 43.7%. cited their occupation as extractivism. A statistically significant negative association was demonstrated between cutaneous leishmaniasis and rainfall between Purus municipalities. However, in regards to the association of cutaneous leishmaniasis for both, temperature and Municipal Human Development Index—MHDI, no significant associations were found in Purus. We concluded that American Tegumentary Leishmaniasis occurring in the Purus Region is related to two distinct aspects: the development of enterprises that extend the agricultural frontier, and a change in lifestyle, namely the extraction of wood as an occupation, which has, as a consequence, an environmental impact and creates difficulties in accessing treatment.

Risk factors for cutaneous leishmaniasis in the rainforest of Bolivia: a cross-sectional study

Background

Cutaneous leishmaniasis (CL) is an endemic disease in Bolivia, particularly in the rainforest of Cochabamba, in the municipality of Villa Tunari. The precarious, dispersed, and poorly accessible settlements in these farming communities make it difficult to study them, and there are no epidemiological studies in the area. The aim of the present study was to identify the risk factors associated with cutaneous leishmaniasis.

Methods

A cross-sectional study was conducted in August 2015 and August 2016 in two communities of Villa Tunari, Cochabamba. The cases were diagnosed through clinical examinations, identification of the parasite by microscopic examination, and the Montenegro skin test. Risk factors were identified through logistic regression.

Results

A total of 274 participants (40.9% female and 59.1% male) were surveyed, of which 43% were CL positive. Sex was the only factor associated with CL with three times more risk for men than for women; this finding suggests a sylvatic mechanism of transmission in the area.

Conclusions

It is advisable to focus on education and prevention policies at an early age for activities related to either leisure or work. Further research is needed to assess the influence of gender-associated behavior for the risk of cutaneous leishmaniasis.

Assessment of a Leishmaniasis Reporting System in Tropical Bolivia Using the Capture-Recapture Method

This study evaluates the level of underreporting of the National Program of Leishmaniasis Control (NPLC) in two communities of Cochabamba, Bolivia during the period 2013-2014. Montenegro skin test-confirmed cases of cutaneous leishmaniasis (CL) were identified through active surveillance during medical campaigns. These cases were compared with those registered in the NPLC by passive surveillance. After matching and cleaning data from the two sources, the total number of cases and the level of underreporting of the National Program were calculated using the capture-recapture analysis. This estimated that 86 cases of CL (95% confidence interval [CI]: 62.1-110.8) occurred in the study period in both communities. The level of underreporting of the NPLC in these communities was very high: 73.4% (95% CI: 63.1-81.5%). These results can be explained by the inaccessibility of health services and centralization of the NPLC activities. This information is important to establish priorities among policy-makers and funding organizations as well as implementing adequate intervention plans.

American cutaneous leishmaniasis in infancy and childhood

Infant and young child skin diseases are among the most common features of morbidity throughout the tropics. Because the skin is directly exposed to the environment, it is considerably affected by climatic and local conditions such as vectors and microorganisms, as in the case of leishmaniasis. In America the observed magnitude of cutaneous leishmaniasis in children has led to the study of increased risk of exposure of this group due to the possibility of peri- and intradomiciliary transmission. The present review pretends to make a concrete approach all through the broad and main figures of this parasitic disease, including the clinical, physiopathological, epidemiological, diagnostic, and therapeutic aspects, in order to be used as a practical source of reference for pediatricians leading with tropical cutaneous pathology in the region.

First report of Warileya rotundipennis (Psychodidae: Phlebotominae) naturally infected with Leishmania (Viannia) in a focus of cutaneous leishmaniasis in Colombia

The expansion of transmission of cutaneous leishmaniasis from sylvatic ecosystems into peri-urban and domestic settings has occurred as sand flies have adapted to anthropogenic environmental modifications. Assessment of the intradomiciliary presence of sand flies in households of the settlement "La Cabaña", in the Department of Risaralda, Colombia, revealed an abundance of Warileya rotundipennis. This unexpected observation motivated further analyses to evaluate the participation of this species in the transmission of cutaneous leishmaniasis. Collections using CDC light traps were conducted during two consecutive nights in May and August 2011.The total of 667 sand flies collected were classified into five species: W. rotundipennis (n=654; 98.05%), Nyssomyia trapidoi (n=7; 1.04%); Lutzomyia (Helcocyrtomyia) hartmanni (n=3; 0.44%); Lutzomyia lichyi (n=2; 0.29%) and Psychodopygus panamensis (n=1; 0.14%). The striking predominance of W. rotundipennis within households during both wet (May) and dry (August) seasons, anthropophilic behavior demonstrated by human blood in 95.23% (60/63) evaluable blood-engorged specimens, and natural infection (5/168-3%) with genetically similar parasites of the Leishmania (Viannia) subgenus observed in a patient in this community, support the involvement of W. rotundipennis in the domestic transmission of cutaneous leishmaniasis in "La Cabaña".

Variability modeling of rainfall, deforestation, and incidence of american tegumentary leishmaniasis in orán, Argentina, 1985-2007

American tegumentary leishmaniasis (ATL) is a disease transmitted to humans by the female sandflies of the genus Lutzomyia. Several factors are involved in the disease transmission cycle. In this work only rainfall and deforestation were considered to assess the variability in the incidence of ATL. In order to reach this goal, monthly recorded data of the incidence of ATL in Orán, Salta, Argentina, were used, in the period 1985-2007. The square root of the relative incidence of ATL and the corresponding variance were formulated as time series, and these data were smoothed by moving averages of 12 and 24 months, respectively. The same procedure was applied to the rainfall data. Typical months, which are April, August, and December, were found and allowed us to describe the dynamical behavior of ATL outbreaks. These results were tested at 95% confidence level. We concluded that the variability of rainfall would not be enough to justify the epidemic outbreaks of ATL in the period 1997-2000, but it consistently explains the situation observed in the years 2002 and 2004. Deforestation activities occurred in this region could explain epidemic peaks observed in both years and also during the entire time of observation except in 2005-2007.

The isolation and molecular characterization of Leishmania spp. from patients with American tegumentary leishmaniasis in northwest Argentina

American tegumentary leishmaniasis (ATL) is a group of zoonotic diseases caused by kinetoplastid flagellates of the genus Leishmania. A total of 66 patients diagnosed as positive ATL cases from northwest Argentina were included in this study. Leishmania stocks were isolated in vitro and analyzed over promastigote cultures sown on FTA through nested PCR and sequence of cytochrome b (cyt b). The molecular analysis resulted in the incrimination of L. (Viannia) braziliensis as the predominant species in the studied area, identifying two genotypes of L. (V.) braziliensis, 24 cases of Ab-1 cyt b and 41 cases of Ab-2 cyt b. One L. (V.) guyanensis strain was obtained from a traveler from the Brazilian Amazon. The prevalence of different genotypes was in agreement with previous studies, suggesting the necessity for new systems to study the genetic diversity in more detail. Most of the cases typified in this study were registered in the area of Zenta Valley (Orán, Hipólito Yrigoyen, and Pichanal cities), pointing a link between genotype and geographical origin of the sample. Sex and age distribution of the patients indicate that the transmission was predominantly associated with rural areas or rural activities, although the results might not exclude the possibility of peri-urban transmission. This work represents, so far, the largest isolation and molecular characterization of ATL cases in Argentina.

Spatio-temporal clustering of American Cutaneous Leishmaniasis in a rural municipality of Venezuela

BACKGROUND

American Cutaneous Leishmaniasis (ACL) is an endemic disease in most Latin-American countries and a public health problem. The number of new cases in the world is thought to be about 1.5 million each year. A new epidemiologic pattern has been observed in the last years, in this sense, Geographic Information Systems (GIS) combined with methods of spatial analysis provide powerful new tools for understanding it.

STUDY OBJECTIVE

To investigate the spatial and temporal features of American Cutaneous Leishmaniasis, in an area known to be endemic.

METHODS

We retrospectively conducted a space-time cluster analysis of incident cases of ACL using cross sectional data recorded from 1348 confirmed cases from 1992 to 2007 in a rural municipality in Venezuela, to test whether the cases were distributed randomly over space and time. We used the space-time permutation scan statistic and GIS. The identified clusters were analyzed for age, sex and job. These allowed us to investigate transmission patterns of ACL without an explicit entomological study.

RESULTS

The analysis showed statistically significant space-time clusters of ACL (p-value<0.01). The most likely cluster contained 35.47% of the total cases (n=177) from 1995 to 1998. Four secondary clusters were identified for different periods. There was an indication of ACL cluster spread from the northeast to other points of the municipality. Three transmission patterns (domiciliary, peri-domiciliary and sylvatic environments) were identified along the study area.

CONCLUSION

The transmission of ACL has a spatial and temporal pattern in the studied area which is related to a complex cycle where the environment and other factors have a significant influence.

Urban transmission of American cutaneous leishmaniasis in Argentina: spatial analysis study

We used kernel density and scan statistics to examine the spatial distribution of cases of pediatric and adult American cutaneous leishmaniasis in an urban disease-endemic area in Salta Province, Argentina. Spatial analysis was used for the whole population and stratified by women > 14 years of age (n = 159), men > 14 years of age (n = 667), and children < 15 years of age (n = 213). Although kernel density for adults encompassed nearly the entire city, distribution in children was most prevalent in the peripheral areas of the city. Scan statistic analysis for adult males, adult females, and children found 11, 2, and 8 clusters, respectively. Clusters for children had the highest odds ratios (P < 0.05) and were located in proximity of plantations and secondary vegetation. The data from this study provide further evidence of the potential urban transmission of American cutaneous leishmaniasis in northern Argentina.

Avaliação de medidas de controle de flebotomíneos no norte do Estado do Paraná, Brasil

Comparam-se os resultados de coletas de flebotomíneos de abril de 2001 a setembro de 2002 com os resultados de coletas de outubro de 1996 a setembro de 1997 e de outubro de 1998 a abril de 2000, para avaliar as medidas empregadas para diminuir a densidade destes insetos, no Recanto Marista, Município de Doutor Camargo, Estado do Paraná, Brasil. As coletas de flebotomíneos foram feitas com armadilhas do tipo Falcão, em domicílios e galinheiros, das 22 às 2 horas, duas vezes ao mês. Em 2001/2002 coletaram-se 199.821 flebotomíneos, com média horária de 1.625,5 insetos; em 1996/1997 e 1997/1998, estas médias foram 1.641,9 e 806,7, respectivamente. Nyssomyia neivai predominou (90,4%) em todos os ecótopos. Esta espécie, juntamente com N. whitmani, Migonemyia migonei e Pintomyia fischeri representaram 99,9% do total coletado. A média horária do total de flebotomíneos aumentou, contudo, 85% destes insetos foram coletados nos galinheiros construídos com a finalidade de atraí-los, diminuindo a densidade dos mesmos nos demais ambientes, especialmente no domicílio.

Leishmaniose tegumentar americana em crianças: aspectos epidemiológicos de casos atendidos em Manaus, Amazonas, Brasil

No período entre janeiro a dezembro de 2005, foram avaliadas crianças de zero a 14 anos de idade com leishmaniose tegumentar americana, atendidas na Fundação de Medicina Tropical do Amazonas; registraram-se 147 casos; 55,78% do sexo masculino; 48,3% procediam do Município de Rio Preto da Eva; 76% procediam de duas estradas. Entre 90 (67,67%) pacientes, entrevistaram-se os responsáveis sobre a moradia na área de transmissão e os hábitos da criança. Desses, 58,89% residiam no local da provável infecção; 60% das crianças penetravam na mata acompanhando os pais; em 91,11% dos casos havia animais domésticos na moradia; 77,78% das residências localizavam-se até 100m de distância da mata; 76,67% pacientes tinham pelo menos um parente com história de leishmaniose tegumentar americana. O padrão de transmissão foi relacionado especialmente a atividades de manejo florestal ocorrendo próximas ao domicílio, habitações próximas à floresta primária, com a ocorrência de leishmaniose tegumentar americana em crianças pequenas, sugerindo transmissão no intra e no peridomicílio, em alguns casos, crianças penetrando na floresta.

The role of dogs as reservoirs of Leishmania parasites, with emphasis on Leishmania (Leishmania) infantum and Leishmania (Viannia) braziliensis

Leishmania parasites cause a group of diseases collectively known as leishmaniases. The primary hosts of Leishmania are sylvatic mammals of several orders (Rodentia, Marsupialia, Carnivora, etc.). Under certain circumstances, particularly in peridomestic and domestic transmission foci, synanthropic and domestic animals can act as source of infection for phlebotomine sand fly vectors. Dogs have long been implicated as the main domestic reservoirs of Leishmania (Leishmania) infantum, the aetiological agent of zoonotic visceral leishmaniasis, and there exists an increasing trend to regard dogs as the main domestic reservoirs of Leishmania (Viannia) braziliensis, the most widespread aetiological agent of American tegumentary leishmaniasis. However, insights derived from recent research indicate that not dogs but humans are probably the most important domestic reservoirs of L. (V.) braziliensis. In the present article, the role of dogs as reservoirs of Leishmania parasites, with emphasis on L. (L.) infantum and L. (V.) braziliensis, is reviewed.

[Epidemiology of tegumentary leishmaniasis in São João, Manaus, Amazonas, Brazil]

In Manaus, Amazonas State, Brazil, the degree of individual exposure to leishmaniasis is related to disorganized land occupation. In order to evaluate predisposing factors for an outbreak, confirm the parasitological diagnosis, treat patients, and assess etiological agents, reservoirs, and vectors, a 12-month study was conducted in Manaus in a community located along the BR-174 federal highway. Some 451 individuals were studied, among whom 17 cases of American tegumentary leishmaniasis (ATL) were diagnosed (six women and 11 men). Age varied from one to 64 years. Eleven patients had from one to three lesions. As for reservoirs, three opossums were captured. No hemoflagellates were found in the blood tests. Lutzomyia umbratilis was the predominant vector species captured. Many ATL patients were engaged in activities that exposed them to Leishmania vectors. Some patients may have been infected in the household and peridomiciliary environments. The epidemiological profile of ATL in this community is similar that of other foci in the region. This case series characterizes ATL as an endemic local public health problem.

Transmissão domiciliar de leishmaniose tegumentar e associação entre leishmaniose humana e canina, durante uma epidemia na Serra de Baturité, no estado de Ceará, Brasil

Em algumas áreas endêmicas de leishmaniose tegumentar(LT) causada por Leishmania (Viannia) braziliensis existem evidências de transmissão domiciliar, e de que cães infectados estariam associados a casos humanos de LT. Neste trabalho, são apresentados os resultados de um estudo realizado na Serra de Baturité, no Ceará, em 1993, quando foram investigadas as evidências de transmissão domiciliar e a associação entre LT humana e infecção canina. Casos humanos de LT foram indivíduos que apresentavam úlceras de bordas elevadas, arredondadas, de diâmetro > 5 mm, duração > 15 dias e uma Reação de Montenegro positiva. Cães soropositivos foram aqueles que apresentavam uma prova de imunofluorescência indireta positiva. A idade foi dividida em dois estratos, de 1 a 10 e 11 a 89 anos. A incidência de LT não estava associada ao sexo (Razão de Incidência (RI) = 1,21; IC 95%: 0,86 - 1,72) e nem à idade (RI = 1,38; IC 95%: 0,97 - 1,96). Para os indivíduos que conviviam com um ou mais cães soropositivos, a incidência de LT humana foi 45% mais elevada (RI = 1,45; IC 95%: 1,02 - 2,06) depois de ajustar para o sexo, e 48% (RI = 1,48%; IC 95%: 1,04 - 2,10) depois de ajustar para idade. Considerando-se o risco domiciliar, a incidência de LT humana foi duas vezes mais elevada (RI = 2,01; IC 95%:1,32 - 3,06) nos domicílios que possuíam um ou mais cães soropositivos. Conclui-se que os indivíduos foram acometidos de LT independente do sexo e da idade e que os casos humanos estavam associados à presença de cães infectados. Portanto, estes resultados suportam a hipótese de transmissão domiciliar da leishmaniose tegumentar na Serra de Baturité, no Ceará.

Aspectos epidemiológicos da leishmaniose tegumentar americana em Varzelândia, Minas Gerais, Brasil

Para caracterizar uma área endêmica de leishmaniose tegumentar americana susceptível de intervenção com candidato à vacina anti-leishmania, foi iniciado em 1999 estudo longitudinal em área rural do Município de Varzelândia, Minas Gerais, Brasil. Inicialmente, foram cadastrados 1.253 indivíduos distribuídos em 246 domicílios, dos quais, 1.170 concordaram em participar do trabalho. Desses, 593 (50,6%) eram masculinos e 662 (56,5%), menores de 21 anos. A intradermorreação de Montenegro foi realizada em 1.120 indivíduos, lida em 1.020 dos casos, e observada reatividade em 282 (27,6%) deles. Anticorpos anti-leishmania foram testados mediante imunofluorescência indireta e teste ELISA em 970 (82,9%) indivíduos, obtendo-se positividade, respectivamente, em 127 (13,1%) e 170 (17,5%) para os dois testes. Na avaliação inicial, foram observados 297 (25,4%) indivíduos com cicatrizes cutâneas semelhantes às deixadas pela doença. Desses, 282 realizaram a intradermorreação que foi positiva em168 (59,61%). A prevalência de casos de leishmaniose tegumentar no início do estudo foi de 5,8% e, depois do primeiro ano, observou-se incidência anual de 4,6% de casos. As características epidemiológicas observadas nesse local sugerem tratar-se de uma área endêmica de colonização antiga.