Clinical evolution of equine leishmaniasis with self-limiting cutaneous disease caused by Leishmania infantum in northeastern Brazil: A case report.

Leishmania infantum infections have long been described in humans and dogs worldwide, but characterization of equine cases remains scarce. We describe the clinical evolution of a natural L. infantum infection to contribute to the diagnostic knowledge and epidemiology of equine leishmaniasis (EL). An auction-acquired four-year-old Mangalarga Marchador mare from Pernambuco state, presented a few subcutaneous nodules on the head and neck upon arrival at the purchaser's stud at Bahia state, in November of 2019. They progressed to multiple ulcerated and non-ulcerated nodules and spread to both right limbs in seven weeks. Hematology revealed anemia, lymphocytosis, monocytosis, and elevated plasma fibrinogen. Histopathology of the biopsied nodules identified a granulomatous dermatitis with macrophages containing Leishmania amastigotes. PCR detected Leishmania in skin lesions, but not in blood or spleen aspirate samples; ITS1 PCR-RFLP and DNA sequencing confirmed L. infantum species. A topical antiseptic and insect-repellent therapy and a monthly follow-up were established. All lesions improved progressively, without specific anti-Leishmania treatment, and 14 months later there was a consistent resolution. This first description of EL by L. infantum in an endemic area is relevant to emphasize the need for epidemiological studies, and to enhance clinicians' awareness for differential diagnosis.

First report of putative Leishmania RNA virus 2 (LRV2) in Leishmania infantum strains from canine and human visceral leishmaniasis cases in the southeast of Brazil

BACKGROUND Leishmania RNA virus 1 (LRV1) is commonly found in South American Leishmania parasites belonging to the subgenus Viannia, whereas Leishmania RNA virus 2 (LRV2) was previously thought to be restricted to the Old-World pathogens of the subgenus Leishmania. OBJECTIVES In this study, we investigated the presence of LRV2 in strains of Leishmania (L.) infantum, the causative agent of visceral leishmaniasis (VL), originating from different hosts, clinical forms, and geographical regions. METHODS A total of seventy-one isolates were screened for LRV2 using semi-nested reverse transcription-polymerase chain reaction (RT-PCR) targeting the RNA-dependent RNA polymerase (RdRp) gene. FINDINGS We detected LRV2 in two L. infantum isolates (CUR268 and HP-EMO) from canine and human cases, respectively. MAIN CONCLUSIONS To the best of our knowledge, this is the first detection of LRV2 in the New World.

Distinct immunomodulatory properties of extracellular vesicles released by different strains of Acanthamoeba.

Free living amoeba of the genus Acanthamoeba are opportunist protozoan involved in corneal, systemic, and encephalic infections in humans. Most of the mechanisms underlying intraspecies variations and pathogenicity are still unknown. Recently, the release of extracellular vesicles (EVs) by Acanthamoeba was reported. However, comparative characterization of EVs from distinct strains is not available. The aim of this study was to evaluate EVs produced by Acanthamoeba from different genotypes, comparing their proteases profile and immunomodulatory properties. EVs from four environmental or clinical strains (genotypes T1, T2, T4, and T11) were obtained by ultracentrifugation, quantitated by nanoparticle tracking analysis and analyzed by scanning and transmission electron microscopy. Proteases profile was determined by zymography and functional properties of EVs (measure of nitrite and cytokine production) were determined after peritoneal macrophage stimulation. Despite their genotype, all strains released EVs and no differences in size and/or concentration were detected. EVs exhibited a predominant activity of serine proteases (pH 7.4 and 3.5), with higher intensity in T4 and T1 strains. EVs from the environmental, nonpathogenic T11 strain exhibited a more proinflammatory profile, inducing higher levels of Nitrite, tumor necrosis factor alpha and interleukin-6 via TLR4/TLR2 than those strains with pathogenic traits (T4, T1, and T2). Preincubation with EVs treated with protease inhibitors or heating drastically decreased nitrite concentration production in macrophages. Those data suggest that immunomodulatory effects of EVs may reflect their pathogenic potential depending on the Acanthamoeba strains and are dependent on protease integrity.

Genetic variant strains of Leishmania (Viannia) braziliensis exhibit distinct biological behaviors.

A variety of clinical forms of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis, as well as differing immune responses of patients, have been reported for an ACL focus in the state of Minas Gerais, Brazil. In addition, two genetic profiles of L. braziliensis have been described, of which one variant profile (hsp70-variant) has been associated with atypical lesions. We investigated the biological behavior of genetic variant strains of L. braziliensis isolated from patients with different clinical manifestations of ACL. Experimental infections were performed with golden hamsters for five L. braziliensis strains in standardized doses of 1 × 106 parasites per inocula. The characteristics of skin lesions, histopathological features, and parasite burden were independently analyzed at 30 and 60 days post-infection. The data revealed distinct patterns in the onset time of visible skin lesions as well as in lesion size and parasite burden among the strains. The extent and density of the inflammatory infiltrate differed among strains, although cellular composition of granulomas appeared similar. Multivariate analysis indicated the occurrence of two clusters: one comprising native strains (cluster 1) and one comprising the reference strain (cluster 2). Within cluster 1, the genetic variants of L. braziliensis did not group with the non-variant strain suggesting that the distinct patterns of biological behavior of these strains could be associated with the known genetic diversity previously described for them.

Seasonality of sand flies (Diptera: Psychodidae) and Leishmania DNA detection in vector species in an area with endemic visceral leishmaniasis

BACKGROUND Leishmaniases are a serious health problem in southeast Brazil, including the city of Belo Horizonte (BH), Minas Gerais state (MG), where there are high rates of incidence and mortality due to visceral leishmaniases. BH is divided into nine sanitary districts (SD) of which one, the Venda Nova SD, was selected for this study because it has high rates of positivity for canine leishmaniasis and high incidence of human leishmaniasis. OBJECTIVES This study aimed to survey the sand fly fauna in Venda Nova SD from August 2011 to July 2013 and perform a descriptive analysis of the vector population. METHODS The sampling was carried out using automatic HP light traps at all covered areas of the Venda Nova SD, in a total of eighteen light traps. Sampled specimens were identified following Galati (2003), and females were submitted to molecular techniques for the detection and identification of Leishmania DNA. A simple environmental description was done for it area and Kernel estimation was used to infer vector density for each study site. FINDINGS A total of 2,427 sand fly specimens belonging to eight species and five genera were collected of which 95.3% were Lutzomyia longipalpis. The seasonal variation curve was delineated by this species. Lu. longipalpis was the most abundant at all collection points and in all months of the study, and exhibited a natural infection rate of 1.01% for Leishmania infantum and 1.77% for Leishmania braziliensis. MAIN CONCLUSIONS The results show the presence and adaptation of Lu. longipalpis to the anthropic environment of BH and reinforces its role as the main vector of L. infantum in the region.

Flebotomíneos (Diptera: Psychodidae) e as Leishmanioses na Terra Indígena Xakriabá, Minas Gerais, Brasil

As leishmanioses são protozooses de alta prevalência em regiões tropicais como o Brasil esão transmitidas por vetores flebotomíneos, cujos hospedeiros são compostos por diferentesespécies animais vertebrados. O objetivo deste trabalho foi estudar os aspectosentomológicos relacionados à epidemiologia das leishmanioses na aldeia Imbaúbas daTerra Indígena Xakriabá, Município de São João das Missões, Minas Gerais. Durante operíodo de julho de 2008 a julho de 2009 foram realizadas seis coletas de flebotomíneossendo dispostas 40 armadilhas luminosas no peridomicílio de 20 casas sorteadasaleatoriamente. Entre outubro de 2011 a agosto de 2012 foram realizadas seis campanhasde captura de flebotomíneos e 20 armadilhas luminosas foram distribuídas em 4 trilhas(cinco armadilhas por trilha) previamente demarcadas para estudo de hospedeiros silvestrese sinantrópicos de Leishmania. Foram utilizados testes estatísticos para avaliar diferençasno padrão de distribuição de espécies, riqueza e abundância de flebotomíneos nosdiferentes ecótopos. Um total de 8.046 flebotomíneos pertencentes a 28 espécies e 11gêneros foram coletados e identificados. As espécies Lutzomyia longipalpis e Nyssomyiaintermedia foram as mais abundantes no peridomicílio enquanto Martinsmyia minasensis eLutzomyia cavernicola as mais abundantes nas trilhas de coleta.

As fêmeas foram dispostasem "pools" contendo no máximo dez espécimes da mesma localidade, espécie e data decoleta para pesquisa de DNA de Leishmania spp. por métodos moleculares. A identificaçãoda espécie de Leishmania foi feita a partir da técnica de ITS1 PCR-RFLP utilizando aenzima HaeIII e o sequenciamento genético para um alvo do gene SSUrRNA. Foi possíveldetectar a presença de DNA de Leishmania em 11 amostras provenientes do peridomicílio:Lu. longipalpis (2), Ny. intermedia (4); Lu. renei (2); Lu. ischnacantha; Micropygomyia goianae Evandromyia lenti. Com relação às trilhas, foi possível verificar a presença de DNA deLeishmania em 12 amostras: Mt. minasensis (5); Ny. intermedia (3); Mi. peresi (2); Mi.capixaba e Ev. lenti. Os resultados obtidos reforçam a importância epidemiológica dasespécies Lu. longipalpis e Ny. intermedia na transmissão da leishmaniose visceral etegumentar respectivamente, além do encontro de outras espécies com DNA de Leishmaniacomo Mt. minasensis e Ev. lenti que podem participar de um ciclo silvestre e/ou sinantrópicode Leishmania na área de estudos.

Flebotomíneos (Diptera: Psychodidae) e as Leishmanioses na Terra Indígena Xakriabá, Minas Gerais, Brasil / Sand flies (Diptera: Psychodidae) and Leishmaniasis in the Indigenous Xakriabá, Minas Gerais, Brazil

As leishmanioses são protozooses de alta prevalência em regiões tropicais como o Brasil esão transmitidas por vetores flebotomíneos, cujos hospedeiros são compostos por diferentesespécies animais vertebrados. O objetivo deste trabalho foi estudar os aspectosentomológicos relacionados à epidemiologia das leishmanioses na aldeia Imbaúbas daTerra Indígena Xakriabá, Município de São João das Missões, Minas Gerais. Durante operíodo de julho de 2008 a julho de 2009 foram realizadas seis coletas de flebotomíneossendo dispostas 40 armadilhas luminosas no peridomicílio de 20 casas sorteadasaleatoriamente. Entre outubro de 2011 a agosto de 2012 foram realizadas seis campanhasde captura de flebotomíneos e 20 armadilhas luminosas foram distribuídas em 4 trilhas(cinco armadilhas por trilha) previamente demarcadas para estudo de hospedeiros silvestrese sinantrópicos de Leishmania. Foram utilizados testes estatísticos para avaliar diferençasno padrão de distribuição de espécies, riqueza e abundância de flebotomíneos nosdiferentes ecótopos. Um total de 8.046 flebotomíneos pertencentes a 28 espécies e 11gêneros foram coletados e identificados. As espécies Lutzomyia longipalpis e Nyssomyiaintermedia foram as mais abundantes no peridomicílio enquanto Martinsmyia minasensis eLutzomyia cavernicola as mais abundantes nas trilhas de coleta.

As fêmeas foram dispostasem "pools" contendo no máximo dez espécimes da mesma localidade, espécie e data decoleta para pesquisa de DNA de Leishmania spp. por métodos moleculares. A identificaçãoda espécie de Leishmania foi feita a partir da técnica de ITS1 PCR-RFLP utilizando aenzima HaeIII e o sequenciamento genético para um alvo do gene SSUrRNA. Foi possíveldetectar a presença de DNA de Leishmania em 11 amostras provenientes do peridomicílio:Lu. longipalpis (2), Ny. intermedia (4); Lu. renei (2); Lu. ischnacantha; Micropygomyia goianae Evandromyia lenti. Com relação às trilhas, foi possível verificar a presença de DNA deLeishmania em 12 amostras: Mt. minasensis (5); Ny. intermedia (3); Mi. peresi (2); Mi.capixaba e Ev. lenti. Os resultados obtidos reforçam a importância epidemiológica dasespécies Lu. longipalpis e Ny. intermedia na transmissão da leishmaniose visceral etegumentar respectivamente, além do encontro de outras espécies com DNA de Leishmaniacomo Mt. minasensis e Ev. lenti que podem participar de um ciclo silvestre e/ou sinantrópicode Leishmania na área de estudos.