Leishmaniasis in Brazil. VII. Further observations on the feeding habitats of Lutzomyia flaviscutellata (mangabeira) with particular reference to its biting habits at different heights

Quality of life of cutaneous leishmaniasis suspected patients in the Ecuadorian Pacific and Amazon regions: a cross sectional study

Background

Yearly, up to 1 million patients worldwide suffer from cutaneous leishmaniasis (CL). In Ecuador, CL affects an estimated 5000 patients annually. CL leads to reduced Health Related Quality of Life (HRQL) as a result of stigma in the Asian and Mediterranean contexts, but research is lacking for Ecuador. The objective of this study was to explore the influence of CL suspected lesions on the quality of life of patients in the Pacific and Amazon regions.

Methods

Patients for this study were included in the Amazonian Napo, Pastaza, and Morona Santiago provinces and the Pacific region of the Pichincha province. Participating centers offered free of charge CL treatment. All patients suspected of CL and referred for a cutaneous smear slide microscopy examination were eligible. This study applied the Skindex-29 questionnaire, a generic tool to measure HRQL in patients with skin diseases. All statistical analysis was done with SPSS Statistics version 28.

Results

The skindex-29 questionnaire was completed adequately by 279 patients who were included in this study. All patient groups from the Amazon scored significantly (P < 0.01) higher (indicating worse HRQL) on all the dimensions of the Skindex-29 questionnaire than Mestizo patients from the Pacific region. The percentage of patients with health seeking delay of less than a month was significantly (P < 0.01) lower in the Amazon region (38%) than in the Pacific (66%).

Conclusions

The present study revealed that the influence of suspected CL lesions on the HRQL of patients in the Ecuadorian Amazon and Pacific depends on the geographic region more than on patient characteristics such as gender, age, number of lesions, lesion type, location of lesions, health seeking delay, or posterior confirmation of the Leishmania parasite. The health seeking delay in the Amazon might result from a lack of health infrastructure or related stigma. Together, the impaired HRQL and prolonged health seeking delay in the Amazon lead to prolonged suffering and a worse health outcome. Determinants of health seeking delay should be clarified in future studies and CL case finding must be improved. Moreover, HRQL analysis in other CL endemic regions could improve local health management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07733-4.

Entomological surveys of Lutzomyia flaviscutellata and other vectors of cutaneous leishmaniasis in municipalities with records of Leishmania amazonensis within the Bragança region of Pará State, Brazil

In southeast Amazon, Lutzomyia (Nyssomyia) flaviscutellata is the incriminated vector of Leishmania (Leishmania) amazonensis, a causative agent of zoonotic cutaneous leishmaniasis (CL). The optimal methods for surveying Lu. flaviscutellata were investigated in the Bragança region, northeast Pará State, Brazil, selected for the presence of Le. amazonensis. The performances of modified Disney traps and CDC light traps were compared in four ecotopes within and around four village transects during the wet and dry seasons. The physiological age of female sand flies was estimated and natural infection by flagellates was evaluated by dissection. Disney traps were better for detecting the presence of Lu. flaviscutellata, while CDC traps performed well for detecting Lutzomyia (Nyssomyia) antunesi, suspected vector of Leishmania lindenbergi. The former was more abundant during the wet season, when female flies were naturally infected with Le. amazonensis. These findings identified the environments of local transmission. In order to improve surveys of Lu. flaviscutellata as part of integrated epidemiological surveillance of CL, our recommendations include focusing vector surveys with Disney traps on forest fragments where people work, during the seasonal peak of the vector. Further field studies are required to make model-based predictions of seasonal variations in the vectorial capacity of vector populations.

Composition of sand fly fauna (Diptera: Psychodidae) and detection of Leishmania DNA (Kinetoplastida: Trypanosomatidae) in different ecotopes from a rural settlement in the central Amazon, Brazil

Background

Phlebotomine sand flies (Diptera: Psychodidae) are vectors of Leishmania species, the etiological agents of leishmaniasis, which is one of the most important emerging infectious diseases in the Americas. In the state of Amazonas in Brazil, anthropogenic activities encourage the presence of these insects around rural homes. The present study aimed to describe the composition and distribution of sand fly species diversity among the ecotopes (intradomicile, peridomicile and forest) in an area of American cutaneous leishmaniasis transmission and detect natural infection with Leishmania DNA to evaluate which vectors are inside houses and whether the presence of possible vectors represents a hazard of transmission.

Results

Phlebotomine sand flies were collected using light traps. A total of 2469 specimens representing 54 species, predominantly females (71.2%), were collected from four sites. Polymerase chain reaction analysis was performed on 670 samples to detect Leishmania DNA. Most of the samples (79.5%) were collected in the forest, with areas closer to rural dwellings yielding a greater abundance of suspected or proven vectors and a larger number of species containing Leishmania DNA. Nyssomyia umbratilis and Bichromomyia flaviscutellata were found near rural homes, and Ny. umbratilis was also found inside homes. Leishmania DNA was detected in different species of sand flies in all ecotopes, including species with no previous record of natural infection.

Conclusions

There is no evidence that vectors of American cutaneous leishmaniasis are becoming established inside homes, but there are sand flies, including Ny. umbratilis and other possible vectors, in environments characterized by a human presence. These species continue to be predominant in the forest but are prevalent in areas closer to ecotopes with a greater human presence. The existence of proven or suspected vectors in this ecotope is due to the structural organization of rural settlements and may represent a hazard of transmission. Although the detection of Leishmania DNA in species that were not previously considered vectors does not mean that they are transmitting the parasite, it does show that the parasite is circulating in ecotopes where these species are found.

Sand Flies (Diptera: Psychodidae) From the Brazilian Atlantic Forest Domain Collected With Malaise Traps

Here, we present the results of a 2-yr sampling using malaise traps along the Atlantic Forest domain from the northeast to the south of Brazil. In total, 217 sand flies were collected, of which the most abundant species was Bichromomyia flaviscutellata (Mangabeira, 1942) (60.4%), followed by Psychodopygus ayrozai (Barretto & Coutinho, 1940) (11%) and Micropygomyia schreiberi (Martins, Falcão & Silva, 1975) (4.1%), and the remaining less abundant species comprised 10.1% of the total of sand flies collected. We report the occurrence for the first time of: 1) B. flaviscutellata, Pintomyia fischeri (Pinto, 1926), Ps. ayrozai, and Psychodopygus carreirai (Barretto, 1946) in the state of Alagoas; 2) Psychodopygus claustrei (Abonnenc, Lèger & Fauran,1979), Psychodopygus amazonensis (Root, 1934), and Sciopemyia sordellii (Shannon & del ponte, 1927) in the state of Bahia; 3) Nyssomyia anduzei (Rozeboom, 1942) in the state of Pernambuco; and 4) B. flaviscutellata, M. schreiberi, Ps. ayrozai, and Psychodopygus davisi (Root, 1934) in the state of Sergipe. Our results present novel records of sand flies collected with malaise traps in the Atlantic Forest domain demonstrating that different collecting methods such as malaise traps can provide new interesting data about these insects that are natural vectors of many pathogens.

Fauna de flebotomíneos (Diptera: Psychodidae) de uma reserva de campina no Estado do Amazonas, e sua importância epidemiológica

INTRODUÇÃO: No Brasil, a maior diversidade de flebotomíneos é encontrada na Região Amazônica, principalmente em floresta primária de terra-firme. No entanto, sua fauna ainda é pouco conhecida em outros ecossistemas desta região. MÉTODOS: a fim de conhecer a fauna de flebotomíneos de outro ecossistema amazônico, coletas com armadilhas de luz CDC foram realizadas em uma área de campina/campinarana na zona periurbana da Cidade de Manaus. RESULTADOS: foram capturados 814 flebotomíneos de 26 espécies, sendo as mais abundantes: Lutzomyia flaviscutellata (64,5%); Lutzomyia georgii (14%); Lutzomyia olmeca nociva (8,1%); Lutzomyia furcata (3,2%); Lutzomyia monstruosa (1,3%); Lutzomyia umbratilis (1,1%) outros (7,8%). CONCLUSÕES: Campina/campinarana revelou-se de grande importância epidemiológica devido a elevada abundância de Lutzomyia flaviscutellata e Lutzomyia olmeca nociva, ambas vetoras de Leishmania (Leishmania) amazonensis. Com base nestas informações, será possível traçar metas para estudos parasitológicos e conscientizar pesquisadores e estudantes, que mantém constante exposição nesta área realizando trabalhos de pesquisa, sobre o possível risco de contaminação por Leishmania.

Further observations on clinical, histopathological, and immunological features of borderline disseminated cutaneous leishmaniasis caused by Leishmania (Leishmania) amazonensis

Leishmania (Leishmania) amazonensis has for some time been considered as the causative agent of two distinct forms of American cutaneous leishmaniasis (ACL): localized cutaneous leishmaniasis (LCL), and anergic diffuse cutaneous leishmaniasis (ADCL). Recently, a new intermediate form of disease, borderline disseminated cutaneous leishmaniasis (BDCL), was introduced into the clinical spectrum of ACL caused by this parasite, and in this paper we record the clinical, histopathological, and immunological features of eight more BDCL patients from Brazilian Amazonia, who acquired the disease in the Pará state, North Brazil. Seven of them had infections of one to two years' evolution and presented with primary skin lesions and the occurrence of metastases at periods varying from six to 12 months following appearance of the first lesion. Primary skin lesions ranged from 1-3 in number, and all had the aspect of an erythematous, infiltrated plaque, variously located on the head, arms or legs. There was lymphatic dissemination of infection, with lymph node enlargement in seven of the cases, and the delayed hypersensitivity skin-test (DTH) was negative in all eight patients prior to their treatment. After that, there was a conversion of DTH to positive in five cases re-examined. The major histopathological feature was a dermal mononuclear infiltration, with a predominance of heavily parasitized and vacuolated macrophages, together with lymphocytes and plasma cells. In one case, with similar histopathology, the patient had acquired his infection seven years previously and he presented with the largest number of disseminated cutaneous lesions. BDCL shows clinical and histopathological features which are different from those of both LCL and ADCL, and there is a good prognosis of cure which is generally not so in the case of frank ADCL.

Estratificação vertical da fauna de flebótomos (Diptera, Psychodidae) numa floresta primária de terra firme da Amazônia Central, Estado do Amazonas, Brasil

Estudos sobre a estratificação vertical da fauna de flebótomos, foram realizados numa floresta primária de terra firme, da Estação Experimental de Silvicultura Tropical - Instituto Nacional de Pesquisas da Amazônia, durante os meses de outubro de 1998 a março de 1999. Utilizando-se armadilhas luminosas CDC, colocadas a 1, 10 e 20 metros de altura do solo, foram coletados 2.859 flebótomos, pertencentes a dois gêneros, Lutzomyia (99,93 %) e Brumtomyia (0,07%), abrangendo 38 espécies. Dentro do gênero Lutzomyia, os sub-gêneros mais representados foram Nyssomyia, com 43,4%, e Psychodopygus com 22,8%. As espécies Lutzomyia umbratilis, L. anduzei, L. rorotaensis, L. trichopyga e L. olmeca nociva, foram dominantes a 1m de altura, enquanto que L. davisi, L. infraspinosa, L. umbratilis, L. trichopyga e L. anduzei, foram dominantes a 10m. As espécies L. anduzei, L. tuberculata, L. dendrophyla e L. dreisbachi foram mais abundantes a 20m. L. umbratilis, presente nos três níveis de estratificação vertical, é dotada de alta importância epidemiológica como vetora da Leishmania (Viannia) guyanensis.

Cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis in Amazonian Brazil, and the significance of a negative Montenegro skin-test in human infections

The clinical and epidemiological features of 62 cases of cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis, from Pará State, Amazonian Brazil, are discussed. The parasite, isolated in hamster skin and/or blood-agar culture medium, was in each case identified by both biological characteristics and a monoclonal antibody specific for promastigotes of L. (L.) amazonensis. Of the 62 patients, 46 (74.2%) presented with a single cutaneous lesion, and on no occasion was evidence found indicating metastatic spread to either the naso-pharyngeal mucosae or the viscera. Recent claims that this parasite may be responsible for both mucocutaneous leishmaniasis and typical visceral leishmaniasis are discussed. Meglumine antimoniate (Glucantime) proved highly efficient in the treatment of all patients. Of the 62 patients examined by the Montenegro skin test, only 32 (51.6%) gave a positive reaction. The significance of this finding is considered and the hypothesis made that the parasite itself may induce an immunoinhibition. Field studies amply confirmed the role of Lutzomyia flaviscutellata as the major sandfly vector of L. (L.) amazonensis in Amazonia.

Leishmaniasis in Brazil: XVI. Isolation and identification of Leishmania species from sandflies, wild mammals and man in north Para State, with particular reference to L. braziliensis guyanensis causative agent of "pian-bois"

A total of 125 wild mammals (14 different species) were examined for evidence of infection with Leishmania in an area of primary forest highly endemic for "pian-bois", due to Leishmania braziliensis guyanensis, in north Pará State, Brazil. Parasites isolated were characterized biologically, and biochemically on enzymic profiles. L. b. guyanensis was isolated from the viscera of one lesser anteater (Tamandua tetradactyla) and one opossum (Didelphis marsupialis), and the skin of one rodent (Proechimys guyannensis). The isolates were indistinguishable from 10 others previously made from the sandfly vectors Lutzomyia umbratilis (five) and Lu. whitmani (five), and nine isolates from field-workers who became infected during these studies. Leishmania mexicana amazonensis was obtained from the skin of 21 animals, including three species of opossums (D. marsupialis, Philander opossum and Metachirus nudicaudatus) and two species of rodents (proechimys guyannensis and Dasyprocta sp.). A peripylarian Leishmania isolated from the viscera of two armadillos (Dasypus novemcinctus) was shown to be different, biologically and biochemically, from L. b. guyanensis and L. m. amazonensis. Four other isolates of Leishmania, from the rodents Rhipidomys leucodactylus (one) and P. guyannensis (three) have yet to be characterized owing to their very poor growth in both hamster skin and in vitro culture: they appear closest, however, to L. braziliensis braziliensis. The complexity of Amazonian leishmaniasis is discussed, and attention drawn to the importance of edentates as reservoir hosts of some leishmanias in the New World. Whereas L. mexicana subspecies appear largely restricted to the skin of their natural hosts, subspecies of L. braziliensis are commonly found in the viscera.