Cases Of American Visceral Leishmaniasis Research Articles

Characterisation of an area of coexistent visceral and cutaneous leishmaniasis transmission in the State of Piauí, Brazil.

In Brazil, transmission of visceral and cutaneous leishmaniasis has expanded geographically over the last decades, with both clinical forms occurring simultaneously in the same area. This study characterised the clinical, spatial, and temporal distribution, and performed entomological surveillance and natural infection analysis of a leishmaniasis-endemic area. In order to characterise the risk of leishmaniasis transmission in Altos, Piauí, we described the clinical and socio-demographic variables and the spatial and temporal distribution of cases of American visceral leishmaniasis (AVL) and American cutaneous leishmaniasis (ACL) cases and identified potential phlebotomine vectors. The urban area concentrated almost 54% of ACL and 86.8% of AVL cases. The temporal and spatial distribution of AVL and ACL cases in Altos show a reduction in the number of risk areas, but the presence of permanent disease transmission foci is observed especially in the urban area. 3,808 phlebotomine specimens were captured, with Lutzomyia longipalpis as the most frequent species (98.45%). Of the 35 females assessed for natural infection, one specimen of Lu. longipalpis tested positive for the presence of Leishmania infantum and Leishmania braziliensis DNA. Our results indicate the presence of risk areas for ACL and AVL in the municipality of Altos and highlight the importance of entomological surveillance to further understand a possible role of Lu. longipalpis in ACL transmission.

American visceral leishmaniasis in a state of northeastern Brazil: clinical, epidemiological and laboratory aspects.

In Brazil, American visceral leishmaniasis (AVL) has become a public health concern due to its high incidence and lethality. This study aimed to analyze the clinical, epidemiological, and laboratory aspects of AVL in a state of Brazil. This descriptive, cross-sectional, retrospective, and quantitative study of notified cases of AVL was carried out in Alagoas between 2008 and 2017 from data obtained from DATASUS/SINAN. Sociodemographic, clinical, and laboratory variables were analyzed. A descriptive analysis was performed using absolute values ​​and valid percentages, using tables and/or graphs. Data processing was performed using Stata 12.0®. Results with P <0.05 were considered statistically significant. During the study period, 352 cases of AVL were reported, of which 6.82% died and 38.92% had met a cure criterion. Male patients were predominant (66.76%). Of the total infected patients, 16.76% had attended only the 1st to the 4th grades, with those most affected aged 1 to 4 years (28.69%). Laboratory diagnostic criteria were most commonly used to confirm the notified cases (76.42%), whereas 51.70% and 8.52% of the cases had positive parasitological and immunofluorescence diagnoses, respectively. Finally, the study showed a higher prevalence of the disease in children, men and in rural residents. Although with low lethality, the expressive frequency of AVL in the State of Alagoas was still verified, since there was an increase in the number of cases during the years of the study.

Phlebotomine sand fly fauna and leishmania infection in the vicinity of the Serra do Cipó National Park, a natural Brazilian heritage site.

In the New World, the leishmaniases are primarily transmitted to humans through the bites of Leishmania-infected Lutzomyia (Diptera: Psychodidae) phlebotomine sand flies. Any or both of two basic clinical forms of these diseases are endemic to several cities in Brazil—the American cutaneous leishmaniasis (ACL) and the American visceral leishmaniasis (AVL). The present study was conducted in the urban area of a small-sized Brazilian municipality (Jaboticatubas), in which three cases of AVL and nine of ACL have been reported in the last five years. Jaboticatubas is an important tourism hub, as it includes a major part of the Serra do Cipó National Park. Currently, no local data is available on the entomological fauna or circulating Leishmania. During the one-year period of this study, we captured 3,104 phlebotomine sand flies belonging to sixteen Lutzomyia species. In addition to identifying incriminated or suspected vectors of ACL with DNA of the etiological agent of AVL and vice versa, we also detected Leishmania DNA in unexpected Lutzomyia species. The expressive presence of vectors and natural Leishmania infection indicates favorable conditions for the spreading of leishmaniases in the vicinity of the Serra do Cipó National Park.

Validity of the polymerase chain reaction in the diagnosis of clinically suspected cases of American visceral leishmaniasis

To test the validity of the polymerase chain reaction for diagnosing American visceral leishmaniasis, 88 suspected cases were studied. Diagnosis was confirmed in 47 (53.5%) and ruled out in 41 (46.5%) patients. Samples of bone marrow and peripheral blood were processed by polymerase chain reaction to evaluate the sensitivity and specificity of the test and its agreement beyond chance with microscopy examination. The polymerase chain reaction was positive in bone marrow of 100% of the patients with amastigotes seen with microscopy examination, and in 59.5% in those where no parasite were seen. Agreement beyond chance between visualization of the parasite in bone marrow aspirates and polymerase chain reaction was considered weak (Kappa=0.41). Concordance between polymerase chain reaction of bone marrow aspirates and of peripheral blood was considered excellent (Kappa=0.88). The test turned out positive in all bone marrow aspirates of those with the disease and whereas the positivity rate was 58.5% among those without the disease, with specificity rate of 41.5%.

Lutzomyia longipalpis (Diptera: Psychodidae) en un foco suburbano de leishmaniosis visceral en el Cañón del Chicamocha en Santander, Colombia.

Between 1998 and 2000, the occurrence of 8 cases of American visceral leishmaniasis in children from a recently established human settlement in Guatiguará, in the municipality of Piedecuesta (Santander, Colombia) indicated the possible presence of Leishmania transmission in this locality. This observation motivated the current entomological investigation. To determine the relative frequency of Lutzomyia longipalpis inside houses and outdoors, and the natural infection of this vector with Leishmania spp. CDC light traps were used for sampling inside houses and outdoors, and sand flies were collected on human volunteers and domestic animals, and in resting places, during the period from May 1999 through September 2000. Natural infection was determined by PCR, in pools of female Lutzomyia longipalpis. A total of 7,391 phlebotomine sand flies were collected. The predominant species was Lutzomyia longipalpis (Lutz & Neiva), representing 99.5% of captures. In the sand flies collected with CDC light traps, L. longipalpis was more frequently collected indoors than outdoors (p = 0.0001). The total rate of natural infection was 1.93% and a positive correlation was observed between months with higher abundance and the number of infected females entering human dwellings. The results indicate that in Guatiguará Lutzomyia longipalpis, shows marked tendency for the indoors, which has important implications for leishmaniasis transmission. Furthermore, transmission risk is increased during the months of higher abundance due to the entry of a higher number of infected females. From the standpoint of control, this behaviour permits the design of strategies to reduce indoor transmission.

Analysis of sandflies (Diptera: Psychodidae) in Barra do Garças, State of Mato Grosso, Brazil, and the influence of environmental variables on the vector density of Lutzomyia longipalpis (Lutz &amp; Neiva, 1912)

Leishmaniasis is an infectious and parasitic zoonotic, non-contagious, vector-borne disease caused by protozoa of the genus Leishmania. In Brazil, the major vector of Leishmania (Leishmania) infantum chagasi (Cunha & Chagas, 1934) is Lutzomyia longipalpis. Barra do Garças, State of Mato Grosso, was designated as a priority area by the Brazilian Ministry of Health for american visceral leishmaniasis, and it is important to identify the vector species present in this municipality. Our objective was to raise sandflies and study the influence of environmental variables on the vector density of Lutzomyia longipalpis. We performed entomological monitoring in 3 districts using Centers for Disease Control and Prevention (CDC) light traps and recorded human cases of american visceral leishmaniasis in the city. We calculated the relative frequency and richness of sandflies and applied a transfer function model to the vector density correlate with relative humidity. The sandfly population was composed of 2 genera and 27 species, totaling 8,097 individuals. Monitoring identified Lutzomyia longipalpis (44%), followed by Lutzomyia lenti (18.9%), Lutzomyia whitmani (13.9%), Lutzomyia carmelinoi (9.1%), Lutzomyia evandroi (5.1%), Lutzomyia termitophila (3.3%), Lutzomyia sordellii (1.9%), and 20 other species (<4%). The male:female ratio was 3.5:1. We observed high species diversity (Dα = 6.65). Lutzomyia longipalpis showed occurrence peaks during the rainy season; there was a temporal correlation with humidity, but not with frequency or temperature. The presence of Lutzomyia longipalpis in the urban area of Barra do Garças underscores the changing disease profile, which was previously restricted to the wild environment.

American Visceral Leishmaniasis in Chiapas, Mexico

We report the results of a study conducted during 1990-2006 with 89 cases of American visceral leishmaniasis in Chiapas State in southeastern Mexico and a seroprevalence study performed with 726 persons and 224 dogs that lived near cases of American visceral leishmaniasis. Clinical aspects, epidemiologic profiles, and risk factors are described. Most cases were in children ≤ 5 years of age, the prevalence of seropositive persons was 77%. The main risk factors associated with this disease were having 1-3 rooms in a house compared with ≥ 4 rooms, having a roof that was not made of cement, and having domestic animals. In contrast, only 19% of dogs were seropositive, suggesting that this species is not important in the transmission cycle of Leishmania. These data indicate that active transmission is taking place in the central valley of Chiapas State, Mexico, in communities located < 1,000 meters above sea level near the Grijalva River.

Use of elisa employing homologous and heterologous antigens for the detection of IgG and subclasses (IgG1 and IgG2) in the diagnosis of Canine visceral leishmaniasis

Indirect immunofluorescence is the method recommended for the diagnosis of visceral leishmanisis in dogs, however, the accuracy of this technique is low and its use on a large scale is limited. Since ELISA does not present these limitations, this technique might be an option for the detection of IgG or specific IgG1 and IgG2 subclasses. Canine ehrlichiosis is an important differential diagnosis of American Visceral Leishmaniasis (AVL). The present study compared ELISA using Leishmania chagasi and Leishmania braziliensis antigen for the detection of anti-Leishmania IgG and subclasses in serum samples from 37 dogs naturally infected with L. chagasi (AVL) and in samples from four dogs co-infected with L. braziliensis and L. chagasi (CI). The occurrence of cross-reactivity was investigated in control serum samples of 17 healthy dogs (HC) and 35 infected with Ehrlichia canis (EC). The mean optical density obtained for the detection of IgG was significantly higher when L. chagasi antigen was used, and was also higher in subgroup VLs (symptomatic) compared to subgroup Vla (asymptomatic). The correlation between IgG and IgG1 was low. The present results suggest that IgG ELISA using homologous antigen yields the best results, permitting the diagnosis of asymptomatic L. chagasi infection and the discrimination between cases of AVL and ehrlichiosis in dogs.

Histopathological and parasitological investigations of ear healthy skin of dogs naturally and experimentally infected with Leishmania (Leishmania) chagasi

Although 90% of clinical cases of American visceral leishmaniasis (AVL) occur in the northeastern region of Brazil, the incidence of cases in recent years has increased in southeastern states such as Minas Gerais (MG), where the disease has been reported in several cities, including Belo Horizonte, the state capital. Some studies have shown a strong correlation between the incidence of AVL and canine visceral leishmaniasis (CVL) in Belo Horizonte. A study of 108 dogs with parasite Leishmania chagasi detected by immuno-histochemistry in healthy ear skin was obtained from two distinct geographical areas: 55 from a metropolitan area of the municipality (Santa Luzia, MG) and 53 dogs from a central area of Belo Horizonte. In parallel, a group of 10 beagles were experimentally infected with L. chagasi. Considering the clinical aspects of all naturally infected dogs, symptomatic dogs were more frequent than asymptomatic ones, especially animals from the metropolitan area compared with the central area (79.6% and 20.3%, respectively). A chronic exudate was observed in the ear of 51 out of 55 dogs naturally infected from the metropolitan area (92.7%) and 45 out of 53 dogs naturally infected from the central area (84.9%). Importantly, asymptomatic dogs from the central area harbor more parasites in the skin than the asymptomatic ones from the metropolitan area. In addition, a profound difference was noted in the intensity of the inflammatory reaction and parasite load in the skin of experimental infected dogs.

American visceral leishmaniasis dissociated from Lutzomyia longipalpis (Diptera, Psychodidae) in the State of Espírito Santo, Brazil

The occurrence of American visceral leishmaniasis in the State of Espírito Santo, Brazil has always been associated with the presence of the Lutzomyia longipalpis vector. The geographic distribution of this vector in this state is related to the presence of specific geoclimatic characteristics, such as a dry climate, low elevations (< 450 m), steep slopes and rocky outcrops. The occurrence of human autochthonous cases of American visceral leishmaniasis in municipalities without these geoclimatic characteristics justifies the present study and our main goal was to test the association between the occurrence of American visceral leishmaniasis and the presence of the Lu. longipalpis. Sand flies were captured monthly from July 2006 to August 2007 using Shannon and CDC traps in two municipalities with records of autochthonous American visceral leishmaniasis and one with no record. We captured 13,112 sand flies, but no Lu. longipalpis was found. The absence of Lu. longipalpis and the possible role of another American visceral leishmaniasis vector in these localities were discussed.

Application of spatio-temporal scan statistics for the detection of areas with increased risk for American visceral leishmaniasis in the state of Bahia, Brazil

Mirroring the global increase of registered cases of American visceral leishmaniasis (AVL), this infection has become a growing public health problem in Brazil during the last several years. As the traditional approach to control employed by the governmental health agencies has failed to reduce the incidence and epidemic outbreaks of this illness, we propose a re-evaluation of the national strategy of intervention and monitoring. Our thinking is based on a series of spatio-temporal scan statistics of the west-central region of the state of Bahia covering the 11-year period from 1994 to 2004. By analyzing the situation, spatially and temporally, we show that the disease is a not only a growing focal threat but that it is also appearing in the form of endemic clusters in the cities. The areas where the disease has been found have been classified according to the degree of risk of infection for humans and canines. The overall objective of this study was to identify areas of increased risk of AVL, including its seasonality, and to suggest ways and means to improve the detection of the disease. The findings presented here should not only be of interest for the efforts to control AVL in the study area but also be useful for developing control strategies in other endemic regions of Brazil.

Lutzomyia longipalpis in Brazil: a complex or a single species? A mini-review

Lutzomyia longipalpis is the main vector of Leishmania infantum chagasi, the causative agent of American visceral leishmaniasis (AVL). Although there is strong evidence that Lu. longipalpis is a species complex, not all data concerning populations from Brazil support this hypothesis. The issue is still somewhat controversial for this large part of Lu. longipalpis distribution range even though that it is the Latin American region contributing to most of the cases of AVL. In this mini-review we consider in detail the current data for the Brazilian populations and conclude that Lu. longipalpis is a complex of incipient vector species with a complexity similar to Anopheles gambiae s.s. in Africa.

Climatic and demographic determinants of American visceral leishmaniasis in northeastern Brazil using remote sensing technology for environmental categorization of rain and region influences on leishmaniasis.

Remote sensing (RS) permits evaluation of spatial and temporal variables that can be used for vector-borne disease models. A Landsat Thematic Mapper scene covering Canindé, Ceará in northeastern Brazil (September 25, 1986) was spectrally enhanced and classified using ERDAS (Atlanta, GA) Imagine for 873 4-km2 areas. The population and number of cases of American visceral leishmaniasis (AVL) were determined for each 4-km2 area. Relative risk (RR) ratios were calculated for climate, demographic, and case data recorded for 17 years by the Municipality of Conidé. The RR of AVL for a child less than 10 years old from the foothills relative to non-foothill residency was 4.0 (95% confidence limit = 3.5, 4.5). The RR of AVL in children was 9.1 during a time when the three-year rolling rain average (current year plus two previous year's precipitation) was between 40 and 60 cm relative to rain greater than 100 cm. The results suggest that features detected by RS techniques combined with climatic variables can be used to determine the risk of AVL in northeastern Brazil.

Trends in the temporal and spatial distribution of visceral and cutaneous leishmaniasis in the state of Bahia, Brazil, from 1985 to 1999

Temporal and spatial trends in the geographical distribution of 12413 cases of American visceral leishmaniasis (AVL) and of 48 138 cases of American cutaneous leishmaniasis (ACL) notified from 1985 to 1999 in the State of Bahia, Brazil, were analysed. The emergence of new endemic municipalities indicated an increasing trend for AVL and ACL. In the years 1985, 1990 and 1996, AVL was endemic in 7% ( n = 31), 18% ( n = 73) and 30% ( n = 123), and ACL was endemic in 13% ( n = 54), 27% ( n = 112) and 34% ( n = 140), of 415 municipalities. New trends were identified, and the relation with the ecoepidemiology of both diseases is discussed.

Visceral leishmaniasis in the Metropolitan Region of Belo Horizonte, State of Minas Gerais, Brazil

In the last few years the number of human cases of American visceral leishmaniasis in the Metropolitan Region of Belo Horizonte (MRBH), Minas Gerais, Brazil has increased, indicating an elevation in the transmission rate of the disease. The total number of notified human cases in the MRBH since 1994, when the first case was identified, up to 1999 was 345 of which 223 (65%) were from the city itself, indicating an urbanization of the disease in this region of Minas Gerais. The age distribution of visceral leishmaniasis cases in the MRBH shows a higher prevalence in children from 0-4 years old, responsible for 28.9% of the notifications. Clinical and immunological findings from dogs infected with Leishmania chagasi are described. The majority of these animals showed no sign of the disease. Sera from all infected dogs showed detectable Leishmania-induced high titles of antibodies based on the results of an indirect fluorescent antibody test. Samples of isolated Leishmania from human and dogs were characterized as L. (L.) chagasi by biochemical and molecular techniques.

Seasonal and nocturnal domiciliary human landing/biting behaviour of Lutzomyia (Lutzomyia) evansi and Lutzomyia (Psychodopygus) panamensis (Diptera; Psychodidae) in a periurban area of a city on the Caribbean coast of eastern Venezuela (Barcelona; Anzoátegui State)

In recent years, in addition to American cutaneous leishmaniasis (ACL), a significant number of cases of American visceral leishmaniasis (AVL) have been reported in periurban areas of Barcelona city (Anzoátegui State, Venezuela). We studied the bionomics of Lutzomyia (Lutzomyia) evansi and Lutzomyia (Psychodopygus) panamensis, possible vectors of AVL and ACL, respectively, in El Rincón, a periurban village of that city. To evaluate the seasonal domiciliary landing/biting activity of sandflies on human bait, a house was chosen in El Rincón. Landing catches were carried out between 18:00 and 06:00, once a month for a year. The results show the presence of 2 species, Lu. (Lu.) evansi (89·9%) and Lu. (Psy.) panamensis (10·1%). Lu. evansi was most abundant in the months of October and July, associated with the bimodal cycle of annual rainfall in the area. Maximum landing/biting activity of Lu. evansi was observed at 24:00 and 03:00. These findings suggest that at this time of the year and at these hours there is heightened risk of the transmission of AVL. Lu. panamensis monthly abundance also shows a direct association with rainfall and maximum landing/biting activity was observed between 02:00 and 03:00. The lower domiciliary abundance of Lu. panamensis suggests its greater importance in the extradomiciliary transmission of ACL.

Alguns dados sobre a leishmaniose visceral americana e doença de Chagas no Nordeste Brasileiro (Relatório de uma excursão realizada nos Estados do Ceará, Pernambuco e Baía)

Antes de nossas pesquisas, nas zonas emque trabalhamos, haviam sido asinalados cinco casos vivos de Leishmaniose Visceral Americana, três no Ceará e dois em Pernambuco. Alem desses, oito tinham sido evidenciados por viscerotomia na Baía, município de Jacobina. Já se tinha conhecimento tambem, de um caso de Doença de Chagas no Ceará. Na confecção do presente trabalho visitamos regiões dos Estados do Ceará, Pernambuco e Baía, onde realizamos rápidos inquéritos epidemiológicos sobre as duas protozooses. No Ceará, região do Cariri, encontramos dois novos casos de Leishmaniose Visceral Americana, cujo diagnóstico foi confirmado pelo exame de esfregaços de polpa esplênica, e cinco de Doença de Chagas, evidenciandos pelos xenodiagnóstico. Foram capturados Flebotomus longipalpis Lutz &amp; Neiva, F. villelai Mangabeira., F. limai Fonseca e F. nordestinus Mangabeira, assim com Panstrongylus megistus (Burm.), 13.5% dos quais infectados. Examinamos animais domésticos (cães e gatos) e silvestres com resultado negativo. Em Pernambuco, município de Exú, fizemos um inquérito sobre os dois casos de Leishmaniose Visceral Americana anteriormente assinalados, não encontrando outros. foram capturados F. longipalpis Lutz &amp; Neiva, alem de Panstrongylus magistus (Burm.) e Triatoma brasiliensis Neiva; nenhum deles estava infectado. Dos animais domésticos foram autopsiados três cães sendo encontrado um com leishmanias no fígado e no baço. O exame de 43 animais silvestres nada revelou. Na Baía, município de Jacobina, encontramos, na zona periférica da cidade, um caso de Leishmaniose visceral Americana e, em outras localidades do município, três outros casos, cujos diagnósticos foram confirmados pelo exame de esfregaços de polpa esplênica; encontramos, também dois casos de Doença de Chagas, evidenciados pelo xenodiagnóstico. Foram capturados F. evandroi Costa Lima, F. lenti Mangabeira e F. longipalpis Lutz &amp; Neiva; Panstrongylus megistus (Burm.) (65.5% infectados) e um exemplar de Eutriatoma maculata (Erich.). Encontramos, tambem, em oco de pau, longe das habitações, um exemplar de P. megistus (Burm.) infectado. Examinamos quatro animais domésticos (cães e gatos), tendo sido encontrado um cão portador de S. cruzi.