Wild and synanthropic reservoirs of Leishmania species in the Americas

Bayesian spatio-temporal modeling to assess the effect of land-use changes on the incidence of Cutaneous Leishmaniasis in the Brazilian Amazon

Cutaneous Leishmaniasis (CL) is a vector-borne disease caused by a protozoan of the genus Leishmania and is considered one of the most important neglected tropical diseases. The Brazilian Amazon Forest harbors one of the highest diversity of Leishmania parasites and vectors and is one of the main focuses of the disease in the Americas. Previous studies showed that some types of anthropogenic disturbances have affected the abundance and distribution of CL vectors and hosts; however, few studies have thoroughly investigated the influence of different classes of land cover and land-use changes on the disease transmission risk. Here, we quantify the effect of land use and land-cover changes on the incidence of CL in all municipalities within the Brazilian Amazon Forest, from 2001 to 2017. We used a structured spatiotemporal Bayesian model to assess the effect of forest cover, agriculture, livestock, extractivism, and- deforestation on CL incidence, accounting for confounding variables such as population, climate, socioeconomic, and spatiotemporal random effects. We found that the increased risk of CL was associated with deforestation, especially modulated by a positive interaction between forest cover and livestock. Landscapes with ongoing deforestation for extensive cattle ranching are typically found in municipalities within the Amazon Frontier, where a high relative risk for CL was also identified. These findings provide valuable insights into developing effective public health policies and land-use planning to ensure healthier landscapes for people.

Detection of DNA of Leishmania infantum in the brains of dogs without neurological signs in an endemic region for leishmaniasis in the state of Rio Grande do Sul, Brazil

Canine visceral leishmaniasis (CVL) is a parasitic disease caused by the protozoan Leishmania infantum. Neurological infection occurs due to the parasite's ability to cross the blood-brain barrier. It is known that dogs can remain infected with a subclinical infection for life, potentially acting as reservoirs for L. infantum when bitten by sandflies. In this context, the objective of this study was to evaluate the occurrence of Leishmania spp. in the brains of dogs from the metropolitan region of Rio Grande do Sul, Brazil, without a history of neurological disease but residing in an endemic area for L. infantum. A total of 200 samples, from 2022 to 2023, were evaluated using conventional Polymerase Chain Reaction (PCR) with the primers Leishmini-F GGKAGGGGCGTTCTGC and Leishmini-R STATWTTACACCAACCCC, aiming to amplify a product of 120 base pairs for Leishmania spp. To identify the species, a multiplex PCR was used, differentiating L. braziliensis (127 bp), L. amazonensis (100 bp), and L. infantum (60 bp), with the molecular target being the conserved region of the kinetoplast DNA (kDNA) minicircle, specific to Leishmania spp. Of the 200 samples evaluated, 26.5% (53/200) tested positive in the conventional PCR reaction for Leishmania spp., with the PCR multiplex the only species detected was Leishmania infantum. The average age of the positive animals was 5.08 years, with 47.2% being females and 52.8% being males; among these, mixed-breed dogs were the most predominant, representing 43.4% of the total. Clinical signs varied: hepatomegaly in two dogs, pronounced neutrophilic hepatitis in one, splenomegaly in one with lymphoid hyperplasia, and glomerulonephritis and nephritis in two animals. Mild anemia and thrombocytopenia were found in eight, with pale mucous membranes in three, and diffuse alveolar edema in one case. Notable pathological findings included suspected distemper in one animal and lymphoplasmacytic meningitis in another. Histopathological findings revealed alveolar edema and acute renal failure. A third dog exhibited bilateral hydrocephalus and diffuse edema in the brain. Additional changes, such as mild inflammatory infiltrate and slight vacuolar degeneration, were observed in 11.3% of the analyzed brains. There was no clinical suspicion of leishmaniasis in any of the studied cases. Therefore, the detection of L. infantum DNA in the brains of dogs suggests that animals with subclinical infection may play a crucial role in the spread of leishmaniasis, and infection by Leishmania spp. should be considered as a differential diagnosis for neurological disease in endemic areas for the protozoan.

Abundance of Leishmania (Kinetoplastida: Trypanosomatidae) vectors in Baldim, a municipality in the Espinhaço Range Biosphere Reserve in Brazil

Leishmaniasis is a zoonoses caused by protozoan parasites belonging to the Leishmania genus that is transmitted to humans through the bite of previously infected phlebotomine sandflies (Diptera:Psychodidae:Phlebotominae). In Brazil, 2 types of leishmaniasis are endemic, tegumentary leishmaniasis (TL) and visceral leishmaniasis (VL). In Baldim, a municipality in the Espinhaço Range Biospere Reserve (ERBR), 5 autochthonous cases of TL, and one autochthonous case of VL were reported from 2017 to 2022. Owing to the lack of data on entomological fauna, we surveyed the occurrence and distribution of phlebotomine sandflies that could act as Leishmania vectors, as well as natural Leishmania infection. During 1 year, 918 sandfly specimens belonging to 12 species were collected. The predominant species was Lutzomyia longipalpis (Lutz & Neiva, 1912) (32.0%), a proven VL agent, followed by Evandromyia evandroi (Costa Lima & Antunes, 1936) (20.7%), Evandromyia cortelezzii (Brèthes, 1923) (17.0%), Nyssomyia whitmani (Antunes & Coutinho, 1939) (12.2%), and Nyssomyia intermedia (Lutz & Neiva, 1912) (10.5%), all putative or proven TL agents. Seasonal fluctuations and endo-exophilic behavior were delineated for the main phlebotomine sandflies. The population of Lu. longipalpis was higher during the coolest and driest months, although different profiles were noted for the other species. Natural Leishmania infection was not detected in any of the 197 phlebotomine sandfly females analyzed. The results were compared with those previously obtained in other municipalities belonging to the ERBR. The presence of Leishmania vectors and human cases of leishmaniasis indicate a risk of Leishmania transmission in the region.

The complexities of blood-feeding patterns in mosquitoes and sandflies and the burden of disease: A minireview

Mosquitoes and sandflies exhibit a wide range of blood feeding patterns, targeting a wide range of vertebrate species, including birds, mammals, reptiles, and amphibians, for proteins vital for egg development. This broad host range increases the opportunity for them to acquire pathogens of numerous debilitating-and-fatal diseases from various animal reservoirs, playing a significant role in disease crossover between animals and humans, also known as zoonotic transmission. This review focuses on the intricate blood-feeding habits of these dipteran vectors, their sensory systems and the complex dance between host and pathogen during disease transmission. We delve into the influence of blood sources on pathogen spread by examining the insect immune response and its intricate interplay with pathogens. The remarkable sense of smell guiding them towards food sources and hosts is explored, highlighting the interplay of multiple sensory cues in their navigation. Finally, we examine the challenges in mosquito control strategies and explore innovations in this field, emphasizing the need for sustainable solutions to combat this global health threat. By understanding the biology and behaviour of these insects, we can develop more effective strategies to protect ourselves and mitigate the burden of vector-borne diseases.

You are what you eat: a systematic review exploring the interaction between Brazilian sand flies and their vertebrate food sources

Sand flies play a crucial role as vectors of bacteria, viruses, and protists, with Leishmania being the most notable among them, transmitted to vertebrate hosts during blood feeding. Understanding the feeding behaviours of sand flies is imperative for gaining insights into their eco-epidemiological roles in the transmission of these infectious agents. This systematic review aimed to answer the question 'What are the blood-feeding sources identified in Brazilian sand flies?' to provide an analysis of their blood-feeding habits. The diverse range of at least 16 vertebrate orders identified as blood sources for 54 sand fly species across different geographic regions was summarised, and the factors potentially associated with the risk of bias in the included studies were analysed. The findings broaden the discussion concerning methods used to identify blood meal sources and shed light on the implications of sand fly feeding behaviours for the transmission dynamics of Leishmania.

Meteorological, demographic, and environmental risk factors for Leishmania infantum in wildlife

Leishmania infantum is an important and neglected vector-borne zoonotic protozoa endemic in the Mediterranean basin. Several wild and domestic mammals can contribute to maintaining its circulation but their importance as effective reservoirs is still under discussion and varies depending on local ecological communities. By combining environmental, climatic, and individual information, this study assessed the presence of L. infantum DNA in a set of wild species from Northwestern Italy and the potential ecological factors related to the risk of infection. From 2020 to 2022, 304 free-ranging wild animals were analyzed for the detection of L. infantum DNA in the spleen and popliteal lymph node (when available). The prevalence obtained in wild boar (Sus scrofa) and roe deer (Capreolus capreolus) was higher than those previously reported (% ± confidence interval 95%; 42.9 ± 18.4% and 27 ± 6.6% in wild boar and roe deer, respectively), and this is the first report of this parasite infecting the coypu Myocastor coypus (60 ± 34.7%). L. infantum DNA was detected in all the seasons including those free of adult sandflies and seasonal differences were minimal, suggesting a long course of infection. The models revealed that animals from rainy areas with higher greenness during the summer, highly populated by humans and predominantly covered by water surfaces had a higher risk of L. infantum. This study contributes to confirming previous findings on the existence of a sylvatic cycle for L. infantum in certain regions of Italy, as well as on the potential epidemiological role of roe deer for this parasite given the elevated prevalence found.

The Parasitemia has Contributed to the Severity of Cases of Visceral Leishmaniasis

Visceral leishmaniasis (VL) occurs due to the evolution, virulence, and adaptation of Leishmania, vector biology, host immune system evasion, and reservoir hosts. Parasitemia can be involved as a warning regarding the clinical severity of VL The present study aims to evaluate the relationship between parasitemia and the prognosis of individuals with VL. Blood and bone marrow samples from individuals with VL were analyzed to identify parasite and quantify or measure parasite burden. Individuals were classified in the clinical score model of risk of death by disease proposed by Coura-Vital et al. (PLoS Negl Trop Dis 8(12): e33742014, 2014). 39/74 individuals presented a better prognosis, and 35/74 individuals presented a worse prognosis. HIV + VL co-infection was present in 32 individuals, of which 12 were considered severe. The group aged 51 to 64 was classified as severe, with a decrease in leukocytes (p-value 0.0295) and neutrophils (p-value 0.0476). L. infantum DNA was identified in blood and bone marrow, in 69 individuals, and not detected in 5 individuals. The quantification of the parasite showed greater parasitemia in bone marrow (P = 0.0003) with an average of 4.70 × 104 Leishmanias/mL about blood, with 0.29 × 104 Leishmanias/mL. Individuals in the age group aged 51 to 64 co-infected with HIV + VL had higher parasitemia (p-value 0.0150) with 2.44 × 104 Leishmanias/mL in blood and bone marrow than in the group aged 20 to 50. Parasitemia, measured by molecular biology in blood and bone marrow, was related to the worst clinical prognosis of VL in the age group aged 51 to 64.

Global Distribution of Canine Visceral Leishmaniasis and the Role of the Dog in the Epidemiology of the Disease

Visceral leishmaniasis is a disease caused by protozoa of the species Leishmania (Leishmania) infantum (syn = Leishmania chagasi) and Leishmania (Leishmania) donovani, which are transmitted by hematophagous insects of the genera Lutzomyia and Phlebotomus. The domestic dog (Canis familiaris) is considered the main urban reservoir of the parasite due to the high parasite load on its skin, serving as a source of infection for sandfly vectors and, consequently, perpetuating the disease in the urban environment. Some factors are considered important in the perpetuation and spread of canine visceral leishmaniasis (CVL) in urban areas, such as stray dogs, with their errant behavior, and houses that have backyards with trees, shade, and organic materials, creating an attractive environment for sandfly vectors. CVL is found in approximately 50 countries, with the number of infected dogs reaching millions. However, due to the difficulty of controlling and diagnosing the disease, the number of infected animals could be even greater. In the four continents endemic for CVL, there are reports of disease expansion in endemic countries such as Brazil, Italy, Morocco, and Tunisia, as well as in areas where CVL is not endemic, for example, Uruguay. Socio-environmental factors, such as migration, drought, deforestation, and global warming, have been pointed out as reasons for the expansion into areas where it had been absent. Thus, the objective of this review is to address (i) the distribution of CVL in endemic areas, (ii) the role of the dog in the visceral leishmaniasis epidemiology and the factors that influence dog infection and the spread of the disease, and (iii) the challenges faced in the control of CVL.

Canine leishmaniasis in the Americas: etiology, distribution, and clinical and zoonotic importance

Canine leishmaniasis is a widespread disease on the American continent, with cases reported from Uruguay to the USA and Canada. While numerous Leishmania spp. have been reported in dogs in this region, Leishmania infantum and Leishmania braziliensis are the most common etiological agents of canine leishmaniasis from a continental perspective. Nonetheless, other species may predominate locally in some countries. The participation of dogs in the transmission cycle of various Leishmania spp. has long been speculated, but evidence indicates that their role as reservoirs of species other than L. infantum is negligible. Various native wildlife (e.g., small rodents, marsupials, sloths, and monkeys) are, in fact, the primary hosts of Leishmania spp. in the Americas. In this review, an updated list of Leishmania spp. infecting dogs in the Americas is presented, along with their distribution and clinical and zoonotic importance.

Alternative hosts of Leishmania infantum: a neglected parasite in Europe

Multi-host pathogens that infect various animal species and humans are considered of great importance for public and animal health. Leishmania spp. parasites are a characteristic example of such pathogens. Although leishmaniosis in humans is endemic for about 100 countries around the world it is classified as a neglected tropical disease. There are three main forms of leishmaniosis in humans: cutaneous (CL), visceral (VL) and mucocutaneous leishmaniosis (MCL). Each year, about 30,000 new cases of VL and more than 1 million new cases of CL are recorded. In Europe L. infantum is the dominant species with dogs being reservoir hosts. Apart from dogs, infection has been recorded in various animals, which suggests that other species could play a role in the maintenance of the parasite in nature. Herein we provide an in-depth review of the literature with respect to studies that deal with Leishmania infantum infections in domestic and wild animal species in Europe. Given the fact that domesticated and wild animals could contribute to the incidences of leishmaniosis in humans, the aim of this paper is to provide a comprehensive review which could potentially be used for the development of measures when it comes to the control of the Leishmania infantum parasite.

The relationships among Leishmania infantum and phyllostomid bats assessed by histopathological and molecular assays

Bats have been reported as reservoir host of Leishmania spp. worldwide, mostly by molecular detection. However, it is still unclear whether bats act as reservoirs of Leishmania infantum to sandflies vectors. In this sense, the investigation of amastigotes forms in the target organs, and the characterization of their associated inflammation, may help to clarify the epidemiological importance of bats in endemic areas for leishmaniasis. The aim of this work was to investigate the host-parasite relationships under microscopic evaluation and predict the epidemiological role of two phyllostomid bats species naturally infected by L. infantum in an endemic area for human leishmaniasis. Fragments of skin, liver and spleen of L. infantum positive and negative bats (Artibeus planirostris and Carollia perspicillata) by qPCR, were studied by histological and immunohistochemical techniques. Both groups, positive and negative, did not show differences in the histopathological study, presenting only discrete tissue changes. Liver and skin showed mild inflammatory reactions. Findings on spleen consisted of reactivity of the lymphoid follicles, expressive presence of apoptotic cells and macrophages containing abundant phagocytic cells debris. We did not find amastigote forms in tissues by histological and IHC techniques in positive qPCR bats. Our results allow us to hypothesize that phyllostomid bats seem to have an important role in reducing the risk of transmission, possibly acting as dead-end host.

Trypanosomatid diversity in a bat community of an urban area in Campo Grande, Mato Grosso do Sul, Brazil

Bats have a long evolutionary history with trypanosomatids, but the role of these flying mammals on parasite transmission cycles in urban areas, especially for Trypanosoma and Leishmania species, remains poorly known. The objective of this study was to evaluate the species richness of trypanosomatids parasitizing a bat community in Campo Grande (CG), a state capital within the Cerrado of the Brazilian Midwest. We evaluated 237 bats of 13 species by means of hemoculture and molecular detection in spleen samples. The bat community of CG appears to participate in the transmission cycles of various species of trypanosomatids. We report an overall trypanosomatid detection rate of 34.2% (n = 81), involving 11 out of 13 sampled bat species. We identified six species of trypanosomatids from 61 bats by analyzing SSU rRNA and/or kDNA: Trypanosoma cruzi DTU TcI, T. c. marinkellei, T. dionisii, Leishmania infantum, L. amazonensis, and T. janseni, with this latter being detected by hemoculture for the first time in a bat species. We also detected a Molecular Operational Taxonomic Unit, Trypanosoma sp. DID, in the phyllostomids Glossophaga soricina and Platyrrhinus lineatus. The highest trypanosomatid richness was observed for Sturnira lilium, which hosted three species: L. infantum, T. dionisii and T. janseni. Given that visceral leishmaniasis is endemic in CG, special focus should be placed on L. infantum. Moreover, L. amazonensis and T. cruzi warrant attention, since these are zoonotic parasites responsible for human cases of tegumentary leishmaniasis and Chagas disease, respectively. In this respect, we discuss how bat communities may influence the Leishmania spp. transmission in endemic areas.

Global Dilemma and Needs Assessment Toward Achieving Sustainable Development Goals in Controlling Leishmaniasis

Leishmaniasis is a disease of poverty that imposes a devastating medical, social, and economic burden on over 1 billion people nationwide. To date, no in-depth study to analyze the major global challenges and needs assessment has been carried out. This investigation aimed to explore a comprehensive narrative review of leishmaniasis's main challenges and initially highlight obstacles that might impede the implementation of control measures. Also, we propose a specific list of priorities for needs assessment. The presence of socioeconomic factors, multiple clinical and epidemiological forms, various Leishmania species, the complexity of the life cycle, the absence of effective drugs and vaccines, and the lack of efficient vector and reservoir control make this organism unique and sophisticated in playing a tangled role to react tricky with its surrounding environments, despite extensive efforts and implementation of all-inclusive former control measures. These facts indicate that the previous strategic plans, financial support, and basic infrastructures connected to leishmaniasis surveillance are still insufficient. Strengthening the leishmaniasis framework in a context of accelerated programmatic action and intensification of cross-cutting activities along with other neglected tropical diseases (NTDs) is confidently expected to result in greater effectiveness, cost-benefit, and fruitful management. Sensitive diagnostics, effective therapeutics, and efficacious vaccines are vital to accelerating advancement toward elimination, and reducing morbidity/mortality and program costs. Collective actions devoted by all sectors and policy-makers can hopefully overcome technical and operational barriers to guarantee that effective and coordinated implementation plans are sustained to meet the road map for NTDs 2021- 2030 goals.

Diversity and dissemination of viruses in pathogenic protozoa

Viruses are the most abundant biological entities on Earth and play a significant role in the evolution of many organisms and ecosystems. In pathogenic protozoa, the presence of viruses has been linked to an increased risk of treatment failure and severe clinical outcome. Here, we studied the molecular epidemiology of the zoonotic disease cutaneous leishmaniasis in Peru and Bolivia through a joint evolutionary analysis of Leishmania braziliensis and their dsRNA Leishmania virus 1. We show that parasite populations circulate in tropical rainforests and are associated with single viral lineages that appear in low prevalence. In contrast, groups of hybrid parasites are geographically and ecologically more dispersed and associated with an increased prevalence, diversity and spread of viruses. Our results suggest that parasite gene flow and hybridization increased the frequency of parasite-virus symbioses, a process that may change the epidemiology of leishmaniasis in the region.

Interactions between Leishmania parasite and sandfly: a review

Leishmaniasis transmission cycles are maintained and sustained in nature by the complex crosstalk of the Leishmania parasite, sandfly vector, and the mammalian hosts (human, as well as zoonotic reservoirs). Regardless of the vast research on human host-parasite interaction, there persists a substantial knowledge gap on the parasite's development and modulation in the vector component. This review focuses on some of the intriguing aspects of the Leishmania-sandfly interface, beginning with the uptake of the intracellular amastigotes from an infected host to the development of the parasite within the sandfly's alimentary canal, followed by the transmission of infective metacyclic stages to another potential host. Upon ingestion of the parasite, the sandfly hosts an intricate repertoire of immune barriers, either to evade the parasite or to ensure its homeostatic coexistence with the vector gut microbiome. Sandfly salivary polypeptides and Leishmania exosomes are co-egested with the parasite inoculum during the infected vector bite. This has been attributed to the modulation of the parasite infection and subsequent clinical manifestation in the host. While human host-based studies strive to develop effective therapeutics, a greater understanding of the vector-parasite-microbiome and human host interactions could help us to identify the targets and to develop strategies for effectively preventing the transmission of leishmaniasis.

Molecular identification of Leishmania tropica in mammals occurring in human-inhabited areas of a cutaneous leishmaniasis endemic focus in North-West Pakistan

Cutaneous Leishmaniasis is endemic in the tribal district of Khyber near the Pak-Afghan border and is caused by Leishmania tropica. In Pakistan, cutaneous leishmaniasis caused by L. tropica is considered anthroponotic and is thought to be maintained by a human-sand fly-human transmission cycle. Along with humans, other mammals may also be acting as reservoir hosts of leishmaniasis in the study area. To investigate the role of non-human mammals in the transmission of leishmaniasis, blood samples were collected from 245 animals from the CL endemic district of Khyber, Pakistan. Leishmania parasite in these samples was detected by amplifying the species-specific sequences in minicircle kinetoplast DNA, using PCR. L. tropica DNA was detected in 18 (7.35%) samples, comprising 11 cows (Bos taurus), 6 goats (Capra hircus), and 1 dog (Canus lupus familiaris). Only a single cow and dog had a leishmaniasis-like lesion, and the remaining positive samples were asymptomatic. None of the tested sheep (Ovis aries) and rat (Rattus rattus, Rattus norvegicus) was positive. The present study reports the first instance of molecular detection of L. tropica in domestic animals. Our study indicates that along with humans' cows, goats and dogs may also be playing an important role in the transmission of anthroponotic cutaneous leishmaniasis in district Khyber in particular and Pakistan in general.

Spatio-temporal distribution and contributing factors of tegumentary and visceral leishmaniasis: A comparative study in Bahia, Brazil

Tegumentary (TL) and visceral (VL) leishmaniasis are neglected zoonotic diseases in Brazil, caused by different parasites and transmitted by various vector species. This study investigated and compared spatio-temporal patterns of TL and VL from 2007 to 2020 in the state of Bahia, Brazil, and their correlations with extrinsic factors. The results showed that the total number of cases of both TL and VL were decreasing. The number of municipalities with reported cases reduced for TL over time but remained almost unchanged for VL. There were few municipalities with reported both diseases. Statistical analysis showed that local TL incidence was associated positively with natural forest. Local VL incidence was associated positively with Cerrado (Brazilian savannah) vegetation. This study identified different patterns of occurrence of VL and TL and the risk areas that could be prioritized for epidemiological surveillance.

Zoonotic Microparasites in Invasive Black Rats (Rattus rattus) from Small Islands in Central Italy

Invasive species have a detrimental impact on native populations, particularly in island ecosystems, and they pose a potential zoonotic and wildlife threat. Black rats (Rattus rattus) are invasive species that disrupt native flora and fauna on islands and serve as potential competent reservoirs for various pathogens and parasites. Microparasites screening was conducted in rat populations from small islands in central Italy (the Pontine Islands and Pianosa) with the aim of assessing the role of rats in maintaining infections, particularly in cases where key reservoir hosts were scarce or absent. We focused on microparasites of zoonotic and veterinary relevance. A total of 53 rats was kill-trapped and target tissues were analysed with molecular techniques. We observed the absence or very low prevalence of Anaplasma spp., while Babesia was found in rats from all locations, marking the first recorded instance of Babesia divergens in wild rats. Data from Pianosa strongly suggest the presence of an autochthonous Leishmania infantum cycle in the Tuscan archipelago islands. Neospora caninum was absent from all islands, even in areas where dogs, the main reservoirs, were present. Toxoplasma gondii was only recorded on the Pontine Islands, where genotyping is needed to shed light on infection dynamics. This study confirms that invasive species, such as rats, may be responsible for maintaining an increased parasitological threat to fauna and human communities in certain ecosystems.

Rodents as vehicle for delivery of transgenic bacteria to make paratransgenic sand fly vectors of cutaneous leishmaniasis in field condition

Vector-borne diseases, among them leishmaniasis, cause more than 700,000 deaths annually. The lack of an effective vaccination and the increasing resistance of sand flies to insecticides require the urgent development of innovative approaches to contain the disease. The use of engineered bacteria that express anti-parasite molecules (paratransgenesis) shows much promise. However, a challenge for implementation of this strategy is to devise means to introduce modified bacteria into sand flies in the field. In this study, we use rodent food bait as a delivery strategy to introduce two mCherry-fluorescent bacteria, Serratia AS1 and Enterobacter cloacae, into adult sand flies in field settings. Bacteria-infected food was provided to Rhombomys opimus rodents. These bacteria transiently pass through the rodent alimentary tract and are delivered to larval habitats with the rodent feces. The feces are ingested by sand fly larvae and, in the case of Serratia AS1, are trans-stadially transmitted to adults. This is the first report of targeting delivery of Serratia AS1 in a paratransgenic system to control transmission of leishmaniasis under field condition. This novel strategy shows promise for delivering transgenic bacteria to Leishmania vectors in the field.

Molecular detection of Leishmania and blood meal analysis in sand flies from Corumbá, Mato Grosso do Sul, Brazil

In this study, we investigated the presence of Leishmania in sand flies collected from a peridomestic area in Corumbá, Mato Grosso do Sul, after an autochthonous case of cutaneous leishmaniasis was confirmed. A total of 1,542 sand flies belonging to seven species were collected, with Lu. cruzi being the most prevalent (94.3%). We detected the presence of DNA from Le. infantum (7 pools) and Le. braziliensis (3 pools) by sequencing the ITS1 amplicon in ten pools, all of which were composed of engorged (3) and non-engorged (7) females of Lu. cruzi. We collected 24 engorged females, with Homo sapiens being the most common blood meal source (91.6%), followed by Dasyprocta azarae and Canis lupus familiaris (4.2% each). To our knowledge, this is the first molecular evidence of Le. braziliensis in wild-caught Lu. cruzi in Brazil, suggesting its potential role as a vector for this parasite.

Invasive mammalian wildlife and the risk of zoonotic parasites

Invasive wild mammals are present in all continents, with Europe, North America, and the Asian-Pacific region having the largest number of established species. In particular, Europe has been the continent with the highest number of zoonotic parasites associated with invasive wild mammals. These invasive species may represent a major threat for the conservation of native ecosystems and may enter in the transmission cycle of native parasites, or act as spreaders of exotic parasites. Here, we review the role of invasive wild mammals as spreaders of zoonotic parasites, presenting important examples from Europe, America, and the Asia-Pacific region. Finally, we emphasize the need for more research on these mammals and their parasites, especially in areas where their monitoring is scantily performed.

Survey of phlebotomine sand fly fauna in a public Zoo in Brazil: Species diversity, seasonality, and host variety

Leishmaniasis is a dynamic disease in which transmission conditions change due to environmental and human behavioral factors. Epidemiological analyses have shown modifications in the spread profile and growing urbanization of the disease, justifying the expansion of endemic areas and increasing number of cases in dogs and humans. In the city of Belo Horizonte, located in the southeastern state of Minas Gerais (Brazil), visceral leishmaniasis (VL) is endemic, with a typical urban transmission pattern, but with different regional prevalence. This study was conducted at the Zoo of the Foundation of Municipal Parks and Zoobotany of Belo Horizonte (FPMZB-BH), located in the Pampulha region, which is among the areas most severely affected by VL. This study aimed to determine the taxonomic diversity of native phlebotomine sand flies (Diptera: Psychodidae), identify climatic variables that potentially affect the phenology of these insects, and determine the blood meal sources for female phlebotomine sand flies. To achieve this, 10 mammal enclosures in the zoo were selected using the presence of possible leishmaniasis reservoirs as a selection criterion, and sampled using light traps between August 2019 and August 2021. A total of 6034 phlebotomine sand flies were collected, indicating nine species, with Lutzomyia longipalpis being the very abundant species (65.35% of the total). Of the 108 engorged phlebotomine collected females, seven samples (6.5%) were positive for blood meals from humans, marsupials, canids, and birds. Relative humidity and rainfall increased the phenology of phlebotomine sand flies, with population increases in the hottest and wettest months. The data obtained will provide guidelines for competent health agencies to implement vector control measures to reduce the risk of leishmaniasis transmission in the FPMZB-BH.

Occurrence of Leishmania infantum in Wild Mammals Admitted to Recovery Centers in Spain

Zoonotic leishmaniasis caused by Leishmania infantum is distributed worldwide and affects humans and domestic and wild mammals. In Europe, specifically in the Mediterranean basin, leishmaniasis is endemic due to the concurrence of the phlebotomine vectors and reservoir mammals, including carnivorous wildlife species and other less studied wild species. In this article, spleen, skin, and eye or oral swabs taken from 134 wild mammals admitted to five wildlife recovery centers in Spain were used. PCR employing fragments of the Repeat region, ITS1, and SSUrRNA were used for detection, and positive samples were processed for sequencing. L. infantum was detected in three out of the nine species analyzed, including European hedgehog, European badger, and red squirrel, with percentages ranging from 11.53 to 35.71%, depending on the species. Most of the species showed higher percentages of positivity in spleen samples than in skin samples. A small number of animals from the remaining six species tested negative, including Algerian hedgehog, stone marten, least weasel, garden dormouse, western polecat, and Egyptian mongoose. Hedgehogs and badgers are good candidates for consideration as epidemiological sentinels and pose a higher risk as potential reservoirs of leishmaniasis based on their percentage of infection and wide distribution.

First molecular description of autochthonous urban cases of canine visceral leishmaniasis in the city of Belém, Pará, Brazil

Leishmaniasis is an anthropozoonosis transmitted by vectors, with dogs being the main domestic reservoirs. Brazil is one of the countries most affected by this disease, and it has been described in humans and dogs in every region in the country. In the northern region leishmaniasis cases in humans have been described in more than 100 municipalities in the State, including the capital, Belém. This study involves two cases of canine visceral leishmaniasis in which the animals developed clinical signs compatible with the disease in urban areas in Belém, the Pará state capital. The diagnosis was confirmed via polymerase chain reaction (PCR) to detect SSUr-rDNA and kDNA of Leishmania sp. and Leishmania infantum, respectively. In one of the cases the animal died and in the other the animal underwent treatment with medicines prescribed for dogs. Through this treatment, parasitemia in the second animal has been kept under control and is being monitored through molecular tests. Previously, no canine cases had been notified from urban neighborhoods in the city of Belém, but only on the island of Cotijuba, at a distance of 29 kilometers from the city. Cases of canine and human leishmaniasis have been recorded close to the capital, Belém, which has areas of conserved vegetation and where the presence of disease vectors has been described. Thus, as has been done in several other Brazilian cities, this study uses clinical and laboratory findings to confirm the presence of autochthonous cases of canine visceral leishmaniasis in the city of Belém.

Leishmania (Viannia) naiffi Lainson & Shaw 1989

Just over 30 years ago, a new species of Leishmania of the subgenus Leishmania (Viannia) was described infecting the armadillo Dasypus novemcinctus; then, a report of human infection followed. From the Brazilian Amazon and apparently restricted to this region and its close borders, Leishmania (Viannia) naiffi has been characterized as a species that grows easily in axenic culture medium and causes few to no lesions after inoculation in experimental animal models. Results in the last decade indicate the occurrence of L. naiffi in vectors and human infections, including a report of therapeutic failure possibly associated with Leishmania RNA virus 1. Overall, such accounts suggest that the parasite is more dispersed and the disease less self-healing than previously expected.

Canine visceral leishmaniasis: risk factors and spatial analysis in an endemic area of Northeastern Brazil

Canine visceral leishmaniasis is a disease caused by the protozoon Leishmania infantum, an important agent of zoonotic concern. In this study we determined the seroprevalence, risk factors and spatial distribution of infection by L. infantum among dogs in the Pajeú microregion of the Sertão region of Pernambuco, Brazil. Canine serum samples (n = 247) were tested using the Dual Path Platform (DPP®) rapid screening test and ELISA/S7® confirmatory test; and risk factors were assessed through univariate analysis and logistical regression. The spatial distribution of reactive dogs was analyzed by drawing a map using QGIS. Seroprevalence of 13.7% (34/247) was detected, with cases predominating in the municipality of Tabira (26.4%; 9/34). Age above 10 years was considered to be a risk factor associated with the presence of anti-L. infantum antibodies. The high overall prevalence and spatial distribution of positive cases showed wide dispersion of reagents dogs in the study area. Therefore, preventive measures are needed in order to reduce the risk of infection for animals and humans.

Phylogenetic and biogeographical traits predict unrecognized hosts of zoonotic leishmaniasis

The spatio-temporal distribution of leishmaniasis, a parasitic vector-borne zoonotic disease, is significantly impacted by land-use change and climate warming in the Americas. However, predicting and containing outbreaks is challenging as the zoonotic Leishmania system is highly complex: leishmaniasis (visceral, cutaneous and muco-cutaneous) in humans is caused by up to 14 different Leishmania species, and the parasite is transmitted by dozens of sandfly species and is known to infect almost twice as many wildlife species. Despite the already broad known host range, new hosts are discovered almost annually and Leishmania transmission to humans occurs in absence of a known host. As such, the full range of Leishmania hosts is undetermined, inhibiting the use of ecological interventions to limit pathogen spread and the ability to accurately predict the impact of global change on disease risk. Here, we employed a machine learning approach to generate trait profiles of known zoonotic Leishmania wildlife hosts (mammals that are naturally exposed and susceptible to infection) and used trait-profiles of known hosts to identify potentially unrecognized hosts. We found that biogeography, phylogenetic distance, and study effort best predicted Leishmania host status. Traits associated with global change, such as agricultural land-cover, urban land-cover, and climate, were among the top predictors of host status. Most notably, our analysis suggested that zoonotic Leishmania hosts are significantly undersampled, as our model predicted just as many unrecognized hosts as unknown hosts. Overall, our analysis facilitates targeted surveillance strategies and improved understanding of the impact of environmental change on local transmission cycles.

Parasite hybridization promotes spreading of endosymbiotic viruses

Viruses are the most abundant biological entities on Earth and play a significant role in the evolution of many organisms and ecosystems. In pathogenic protozoa, the presence of endosymbiotic viruses has been linked to an increased risk of treatment failure and severe clinical outcome. Here, we studied the molecular epidemiology of the zoonotic disease cutaneous leishmaniasis in Peru and Bolivia through a joint evolutionary analysis of Leishmania braziliensis parasites and their endosymbiotic Leishmania RNA virus. We show that parasite populations circulate in isolated pockets of suitable habitat and are associated with single viral lineages that appear in low prevalence. In contrast, groups of hybrid parasites were geographically and ecologically dispersed, and commonly infected from a pool of genetically diverse viruses. Our results suggest that parasite hybridization, likely due to increased human migration and ecological perturbations, increased the frequency of endosymbiotic interactions known to play a key role in disease severity.

Phlebotominae Fauna (Diptera: Psychodidae) and the Spatial Distribution of Species in Sergipe, Brazil

Some sand fly species are the vectors responsible for the transmission of Leishmania spp. (Kinetoplastida: Trypanosomatidae), the etiological agent of leishmaniasis, and in the state of Sergipe, the two main forms of the disease (visceral and cutaneous) are recorded. Few works show information about the species that form the Phlebotominae fauna in Sergipe. This study aimed to update and determine how they are distributed throughout the state. The study used data from surveys about phlebotomines in Sergipe, from the Program of Surveillance and Control of Visceral Leishmaniasis, carried out by the Central Public Health Laboratory of Sergipe, from 2008 to 2018, along with review and original data from 2022. The commentary on this information was developed with focus on the species that can be vectors for the disease. Sergipe has, up to now, 27 registered species of phlebotomines from 12 genera, 15 of them are of sanitary relevance. Twenty two of these species are in the mesoregion East, 19 in the Agreste, and 11 in the Sertão of Sergipe. The species with the greatest distribution was Evandromyia lenti (Mangabeira, 1938), present in 74.6% of the municipalities of Sergipe, followed by Lutzomyia longipalpis (Lutz & Neiva, 1912), the main vector of the etiological agent of visceral leishmaniasis in Brazil, present in 68% of the municipalities studied. This study expands the number and distribution of species recorded in the state. This information can contribute to disease containment plans and support health education actions aimed at the control of leishmaniasis in Sergipe.

Serodiagnosis of leishmaniasis in asymptomatic and symptomatic dogs by use of the recombinant dynamin-1-like protein from Leishmania infantum: A preliminary study

Visceral leishmaniasis (VL) is a fatal manifestation of an infection caused by intracellular protozoa of the Leishmania genus. In New World countries, VL is classified as a zoonotic disease with domestic dogs acting as its main reservoir. Asymptomatic dogs are as competent to transmit Leishmania to the vectors as symptomatic dogs, however current diagnostic tests are limited and present low sensitivity for this important group. The development of accurate tests is fundamental to the early diagnosis, treatment, and control of canine leishmaniasis. In this study, we investigated the use of a recombinant protein (dynamin-1-like protein, Dyn-1) from L. infantum, as a potential target antigen for leishmaniasis serodiagnosis in both symptomatic and asymptomatic dogs. The antigenic performance of the protein was evaluated by means of ELISA assays using sera from symptomatic (n = 25), asymptomatic (n = 34) and non-infected dogs (n = 36) using ELISA. In addition, sera from dogs experimentally infected with Trypanosoma cruzi (n = 49) and naturally infected with Babesia sp. (n = 8) were tested to evaluate possible cross-reactivity. A crude soluble antigen (CSA) of Leishmania was used as an antigen control and K39 and K26 were used as reference antigens because they are already widely used in commercial tests. rDyn-1-based assay showed the highest sensitivity (97%) compared to the antigens K39 (88%), K26 (86%) and crude extract (95%). The highest specificity among the tests was also obtained with the protein rDyn-1 (94%), compared with the other antigens K39 (81%), K26 (87%), and crude extract (77%). This study showed that the rDyn-1 ELISA assay was able to identify 100% of asymptomatic dogs, establishing its potential as a target for the diagnosis of canine leishmaniasis.

Arthropod-Borne Pathogens in Wild Canids

Wild canids, as well as other wild animal species, are largely exposed to bites by ticks and other hematophagous vectors where the features favoring their presence and spread are found in wooded and semi-wooded areas. Much of the information about arthropod-borne infections concerns domestic and companion animals, whereas data about these infections in wild canids are not exhaustive. The present study is a narrative review of the literature concerning vector-borne infections in wild canids, highlighting their role in the epidemiology of arthropod-borne bacteria and protozoa.

High levels of infectiousness of asymptomatic Leishmania (Viannia) braziliensis infections in wild rodents highlights their importance in the epidemiology of American Tegumentary Leishmaniasis in Brazil

BACKGROUND

The epidemiological significance of wildlife infections with aetiological agents causing human infectious diseases is largely determined by their infection status, contact potential with humans (via vectors for vector-borne diseases), and their infectiousness to maintain onward transmission. This study quantified these parameters in wild and synanthropic naturally infected rodent populations in an endemic region of tegumentary leishmaniasis in northeast Brazil.

METHODS

Capture-mark-recapture (CMR) of rodents was conducted over 27 months in domestic/peri domestic environs, household plantations and nearby Atlantic Forest (9,920 single trap nights). Rodent clinical samples (blood and ear tissue) were tested for infection by conventional PCR and quantitative PCR (qPCR) for Leishmania (Viannia) braziliensis, and xenodiagnosis to measure infectiousness to the local sand fly vector.

RESULTS

A total 603 individuals of 8 rodent species were (re)captured on 1,051 occasions. The most abundant species were Nectomys squamipes (245 individuals, 41% of the total catch), Rattus rattus (148, 25%), and Necromys lasiurus (83, 14%). All species were captured in greater relative frequencies in plantations; R. rattus was the only species captured in all three habitats including in and around houses. Four species, comprising 22.6% of individuals captured at least twice, were geolocated in more than one habitat type; 78.6% were infected with L. (V.) braziliensis, facilitating inter-species and inter-habitat transmission. Species specific period prevalence ranged between 0%-62% being significantly higher in N. squamipes (54-62%) and Hollochillus sciureus (43-47%). Xenodiagnosis was performed on 41 occasions exposing 1,879 Nyssomyia whitmani sand flies to five rodent species (37 individuals). Similar mean levels of infectiousness amongst the more common rodent species were observed. Longitudinal xenodiagnosis of the N. squamipes population revealed a persistent level of infectiousness over 13 months follow-up, infecting a median 48% (IQR: 30.1%-64.2%) of exposed blood-fed vectors. The proportion of exposed flies infected was greater in the low compared to in the high seasonal period of vector abundance. L. (V.) braziliensis parasite loads in rodent blood quantified by qPCR were similar across rodent species but did not represent a reliable quantitative marker of infectiousness to sand flies. The standardised risk of rodent infection in plantations was 70.3% relative to 11.3% and 18.4% in peri domestic and forest habitats respectively. R. rattus was the only exception to this trend indicating greatest risk in the peri domestic environment.

CONCLUSIONS

The results support the view that a collective assemblage of wild and synanthropic rodent species is an important wild reservoir of L. (V.) braziliensis in this region, with N. squamipes and R. rattus probably playing a key role in transmission within and between habitat types and rodent species. Rodents, and by implication humans, are at risk of infection in all sampled habitats, but more so in homestead plantations. These conclusions are based on one of the longest CMR study of small rodents in an American Tegumentary Leishmaniasis (ATL) foci.

Molecular detection of the natural infection by trypanosomatid parasites in Didelphis marsupialis from a rural area in northern Colombia

We studied the prevalence of infection by trypanosomatid parasites in Didelphis marsupialis and its relationship with morphological/age aspects in a rural area of El Carmen de Bolivar, Colombia. Five visits were made to the Vereda El Alférez; each of which lasted three consecutive nights. During these visits, Tomahawk® traps were installed in the peridomestic and wild ecotopes of the Vereda El Alférez. Body measurements, sex and age were determined from the collected animals. Blood was extracted by cardiopuncture, after sedation, in order to obtain total deoxyribonucleic acid (DNA) and amplify the conserved region of the kinetoplast minicircle DNA (kDNA) of parasitic trypanosomatids. The association between morphological parameters of didelphids and their frequency of infection by parasitic trypanosomatids was determined by binomial regression. Thirty D. marsupialis specimens (60.0% females and 40.0% males/66.7% adults and 33.3% juveniles) were collected. Molecular diagnosis revealed a frequency of trypanosomatid parasite infection of 46.7%. Stage (p=0.024) was a determinant for infection. We discuss the role of D. marsupialis as a potential reservoir of parasitic trypanosomatids in the Vereda El Alférez.

Cutaneous Leishmaniasis Emergence in Southeastern Mexico: The Case of the State of Yucatan

Environmental changes triggered by deforestation, urban expansion and climate change are present-day drivers of the emergence and reemergence of leishmaniasis. This review describes the current epidemiological scenario and the feasible influence of environmental changes on disease occurrence in the state of Yucatan, Mexico. Relevant literature was accessed through different databases, including PubMed, Scopus, Google, and Mexican official morbidity databases. Recent LCL autochthonous cases, potential vector sandflies and mammal hosts/reservoirs also have been reported in several localities of Yucatan without previous historical records of the disease. The impact of deforestation, urban expansion and projections on climate change have been documented. The current evidence of the relationships between the components of the transmission cycle, the disease occurrence, and the environmental changes on the leishmaniasis emergence in the state shows the need for strength and an update to the intervention and control strategies through a One Health perspective.

Sequencing of hsp70 for discernment of species from the Leishmania (Viannia) guyanensis complex from endemic areas in Colombia

BACKGROUND

Colombia is ranked very high among countries with the highest numbers of endemic Leishmania species (n = 9) causing human disease. Although much effort has been devoted to generating simple and specific tools for Leishmania species identification, challenges remain in the discrimination of species belonging to the Leishmania (Viannia) guyanensis complex: L. (V.) guyanensis and L. (V.) panamensis.

METHODS

A set of seven reference strains of species belonging to the L. (Leishmania) and L. (Viannia) subgenera, clinical strains from human cases of cutaneous leishmaniasis (CL; n = 26) and samples collected from sylvatic mammals and sand flies (n = 7) from endemic areas in Colombia were analyzed in this study. The heat-shock protein 70 gene (hsp70) was amplified by PCR from DNA extracted from logarithmic-phase promastigotes or tissue samples, and the PCR products were sequenced. Sequence alignment was performed against a set of previously published and curated sequences, and phylogenetic analysis based on the maximum-likelihood and Bayesian inference approaches was conducted. Haplotype diversity among strains and species of the L. (V.) guyanensis complex was explored using a median-joining network.

RESULTS

Sequencing of the hsp70 gene for L. (Viannia) spp. typing was comparable to species identification using isoenzyme electrophoresis or monoclonal antibodies. Complete species matching was found, except for one sylvatic sample with an identity yet unsolved. Among the L. (V.) panamensis clinical strains, two distinctive phylogenetic clusters were found to correlate with two different zymodemes: L. (V.) panamensis Z2.2 and Z2.3. Analysis of samples from sylvatic environments identified novel records of naturally infected wild mammal and sand fly species.

CONCLUSIONS

Our results support the adequacy of hsp70 gene sequencing as a single-locus approach for discrimination of L. (Viannia) spp., as well as for exploring the genetic diversity within the L. (V.) guyanensis complex.

Novel Ehrlichia and Hepatozoon genotypes in white-eared opossums (Didelphis albiventris) and associated ticks from Brazil

White-eared opossums (Didelphis albiventris) are well adapted to anthropized areas. The increased contact with domestic animals and humans mediates the transmission of arthropod-borne pathogens. Despite the worldwide occurrence of tick-borne Anaplasmataceae and Hepatozoidae species in a variety of vertebrates, few studies reported serological evidence or molecular detection of theses agentes in marsupials. Up to now, while Ehrlichia/Anaplasma spp. have only been detected in marsupials from Brazil, Hepatozoon spp. have been reported in marsupials from Chile, Australia and Brazil. The present work aimed to investigate, using molecular techniques and blood smear analysis, the presence of Ehrlichia spp., Anaplasma spp., and Hepatozoon sp. in the blood and ticks collected from D. albiventris in urban forest fragments from midwestern Brazil. Between May and December 2017, 43 D. albiventris (27 males and 16 females) were captured for blood and tick collection in the city of Campo Grande, state of Mato Grosso do Sul, midwestern Brazil. Ticks (46 Amblyomma dubitatum nymphs and 24 Amblyomma spp. larvae) were collected from 14 out 43 (32.5%) of the white-eared opossums. Panoptic-stained blood smears were performed using peripheral blood (tail tip) of the captured opossums. DNA extracted from blood and tick samples were subjected to PCR/qPCR assays for Anaplasmataceae agents (rrs, gltA, groEL, sodB, and dsb genes, and 23S-5S intergenic region) and Hepatozoon spp. (18S rRNA gene), followed by Sanger sequencing, BLASTn and phylogenetic analyses. An inclusion resembling Ehrlichia morulae was found in a white-eared opossum's monocyte from a blood smear stained with Panoptic. Five (11.63% [5/43]) white-eared opossums' blood samples and 7 (25% [7/28]) tick samples (2 pools of Amblyomma spp. larvae and 5 pools of A. dubitatum nymphs) were positive for Anaplasmataceae via a PCR assay targeting the conserved rrs gene. Phylogenetic analysis based on the rrs gene positioned three sequences obtained from opossums and ticks together as a subclade within the Ehrlichia canis clade. However, all samples were negative in a qPCR assay specific for E. canis based on the dsb gene. Phylogenetic analyses positioned the gltA and 23S-5S ITS sequences obtained from opossums' blood samples in a separate clade from the other validated Ehrlichia species. One (2.3% [1/43]) opossum blood sample was positive for the 18S rRNA gene of Hepatozoon sp. The phylogenetic analysis positioned the Hepatozoon sp. sequence obtained from a D. albiventris specimen in a clade with a sequence previously detected in a black storm petrel (Oceanodroma melania) from Mexico. All the other sequences of Hepatozoon sp. previously detected in marsupials from Brazil were positioned in a separated clade. The present work showed the occurrence of putative novel genotypes of Ehrlichia sp. and Hepatozoon sp. in white-eared opossums and associated A. dubitatum ticks from midwestern Brazil.

Roe deer (Capreolus capreolus) are a novel potential reservoir for human visceral leishmaniasis in the Emilia-Romagna region of northeastern Italy

Leishmaniasis is a complex human disease caused by intracellular parasites of the genus Leishmania, predominantly transmitted by the bite of sand flies. In Italy, leishmaniasis is caused exclusively by Leishmania infantum, responsible for the human and canine visceral leishmaniases (HVL and CVL, respectively). Within the Emilia-Romagna region, two different foci are active in the municipalities of Pianoro and Valsamoggia (both in the province of Bologna). Recent molecular studies indicated that L. infantum strains circulating in dogs and humans are different, suggesting that there is an animal reservoir other than dogs for human visceral leishmaniasis in the Emilia-Romagna region. In this work, we analyzed specimens from wild animals collected during hunts or surveillance of regional parks near active foci of human visceral leishmaniasis for L. infantum infection in the province of Bologna. Out of 70 individuals analyzed, 17 (24%) were positive for L. infantum. The infection prevalence in hedgehogs (Erinaceus europaeus), roe deer (Capreolus capreolus), badgers (Meles meles), and bank voles (Myodes glareolus) was 80, 33, 25, and 11%, respectively. To distinguish the two strains of L. infantum we have developed a nested PCR protocol optimized for animal tissues. Our results demonstrated that most (over 90%) of L. infantum infections in roe deer were due to the strain circulating in humans in the Emilia-Romagna region.

Artificial blood-feeding of phlebotomines (Diptera: Psychodidae: Phlebotominae): is it time to repurpose biological membranes in light of ethical concerns?

BACKGROUND

The aims of the present study were to evaluate and compare the efficacy of blood-feeding in phlebotomines through industrially processed membranes from the small intestine of pigs (used for the production of commercial sausages) and the skin of euthanized chicks.

METHODS

Laboratory-bred Lutzomyia longipalpis and different field-caught phlebotomine species were subjected to the artificial feeding systems under similar conditions. Paired tests were performed using the control (skin from euthanized chicks) and test membranes (pig small intestine). The feeding rates were compared by paired t-test, and Pearson correlation was used to examine the relationship between the thickness of the membranes and feeding rate.

RESULTS

The feeding rate was greater with the test membrane than with the control membrane for L. longipalpis (t-test, t = -3.3860, P = 0.0054) but not for the most frequent field-caught species, Nyssomyia antunesi (t-test, t = 0.7746, P = 0.4535). The average thicknesses of the control and test membranes were 184 ± 83 µm and 34 ± 12 µm, respectively (Mann-Whitney U-test, U = 0.00, Z = 2.8823, P = 0.0039); however, there was no correlation between feeding rate and membrane thickness. A moderate positive correlation was observed between the number of phlebotomines that fed and the total number of phlebotomines in the cage for each type of membrane and for each species.

CONCLUSIONS

The test membrane is a viable alternative for the artificial blood-feeding of phlebotomines, and is thus a potential substitute for the skin of animals that are euthanized for this purpose. Feeding rate was independent of membrane thickness.

Livestock and rodents within an endemic focus of Visceral Leishmaniasis are not reservoir hosts for Leishmania donovani

Leishmaniasis on the Indian subcontinent is thought to have an anthroponotic transmission cycle. There is no direct evidence that a mammalian host other than humans can be infected with Leishmania donovani and transmit infection to the sand fly vector. The aim of the present study was to evaluate the impact of sand fly feeding on other domestic species and provide clinical evidence regarding possible non-human reservoirs through experimental sand fly feeding on cows, water buffalo goats and rodents. We performed xenodiagnosis using colonized Phlebotomus argentipes sand flies to feed on animals residing in villages with active Leishmania transmission based on current human cases. Xenodiagnoses on mammals within the endemic area were performed and blood-fed flies were analyzed for the presence of Leishmania via qPCR 48hrs after feeding. Blood samples were also collected from these mammals for qPCR and serology. Although we found evidence of Leishmania infection within some domestic mammals, they were not infectious to vector sand flies. Monitoring infection in sand flies and non-human blood meal sources in endemic villages leads to scientific proof of exposure and parasitemia in resident mammals. Lack of infectiousness of these domestic mammals to vector sand flies indicates that they likely play no role, or a very limited role in Leishmania donovani transmission to people in Bihar. Therefore, a surveillance system in the peri-/post-elimination phase of visceral leishmaniasis (VL) must monitor absence of transmission. Continued surveillance of domestic mammals in outbreak villages is necessary to ensure that a non-human reservoir is not established, including domestic mammals not present in this study, specifically dogs.

Polymeric Approach to Adjuvant System in Antibody Production against Leishmaniasis Based on Hybridoma Technology

Background

Leishmaniasis is a zoonotic disease, which is one of the serious public health problems in the world. Nowadays, antibody production using hybridoma technology may be a correct approach in terms of sensitivity in the diagnosis of diseases such as leishmaniasis. The aim of this study was investigation of the effectiveness of different adjuvants on polyclonal antibody production against L. tropica based on hybridoma technique.

Methods

Accordingly, Freund's adjuvant (1956, M. tuberculosis), as a classic adjuvant in studies, was used comparatively with the non-toxic polymeric based Polyoxidonium adjuvant. All animal immunization procedures were conducted at Bezm-i Alem University Experimental Animal Research Center. The adjuvant response was tested both in the serum sample and in the antibodies produced by the hybridomas. The antibody titers were determined with ELISA.

Results

Freund's and Polyoxidonium (PO) group blood titer's increased approximately 5.5 fold compared to control after the 6th and 8th immunization. Hybridomas produced from mice immunized with PO adjuvant induced only antigen-specific antibody response and did not develop an immune response against the adjuvant.

Conclusion

Adjuvant selection is very important in terms of the specificity of antibody responses of cells produced in hybridoma technology. Therefore, PO is recommended as a new adjuvant system in this study.

Investigation of Chlamydia sp., Morbillivirus sp., Parvovirus sp., Leishmania sp. and Alphacoronavirus sp. in captive giant anteaters (Myrmecophaga tridactyla)

ABSTRACT This research aimed to investigate the occurrence of Chlamydia sp., Morbillivirus sp., Parvovirus sp., Leishmania sp. and Alphacoronavirus sp. in captive giant anteaters. Blood and fecal samples were taken from 16 animals in institutions from the states of Minas Gerais, Bahia and Distrito Federal, which had been in captivity for at least a year. A commercial rapid chromatographic immunoassay test was used for detecting coronavirus and parvovirus antigens, in addition to antibodies against leishmaniasis, all results being negative. In the case of the test for antibodies against distemper, four (4/16; 25%) anteaters had an average titration, two (2/16; 12.5%) a low titration and ten (10/16; 62.5%) were non-reactive. Using the DOT-ELISA (dot blotting) method for detection of immunoglobulin G, only one specimen obtained a 1 : 40 titration. For the polymerase chain reaction tests for Leishmania and Chlamydia, all samples were negative.

Leishmaniasis and Chagas disease: Is there hope in nanotechnology to fight neglected tropical diseases?

Nanotechnology is revolutionizing many sectors of science, from food preservation to healthcare to energy applications. Since 1995, when the first nanomedicines started being commercialized, drug developers have relied on nanotechnology to improve the pharmacokinetic properties of bioactive molecules. The development of advanced nanomaterials has greatly enhanced drug discovery through improved pharmacotherapeutic effects and reduction of toxicity and side effects. Therefore, highly toxic treatments such as cancer chemotherapy, have benefited from nanotechnology. Considering the toxicity of the few therapeutic options to treat neglected tropical diseases, such as leishmaniasis and Chagas disease, nanotechnology has also been explored as a potential innovation to treat these diseases. However, despite the significant research progress over the years, the benefits of nanotechnology for both diseases are still limited to preliminary animal studies, raising the question about the clinical utility of nanomedicines in this field. From this perspective, this review aims to discuss recent nanotechnological developments, the advantages of nanoformulations over current leishmanicidal and trypanocidal drugs, limitations of nano-based drugs, and research gaps that still must be filled to make these novel drug delivery systems a reality for leishmaniasis and Chagas disease treatment.

Vector-borne pathogens of zoonotic concern in dogs from a Quilombola community in northeastern Brazil

Canine vector-borne pathogens (CVBPs) comprise a group of disease agents mainly transmitted by ticks, fleas, mosquitoes and sand flies. In this study, we assessed the presence of CVBPs in an Afro-descendent community (Quilombola) of northeastern, Brazil. Dog blood samples (n = 201) were collected and analyzed by rapid test for the detection of antibodies against Leishmania spp., Anaplasma spp., Ehrlichia spp. and Borrelia burgdorferi sensu lato (s.l.), and antigens of Dirofilaria immitis. In addition, polymerase chain reactions were performed for Anaplasmataceae, Babesia spp., Hepatozoon spp., Rickettsia spp. and B. burgdorferi s.l. Overall, 66.7% of the dogs scored positive to at least one pathogen at serological and/or molecular methods. Antibodies against Ehrlichia spp. were the most frequently detected (57.2%; n = 115/201), followed by Anaplasma spp. (8.5%; n = 17/201), Leishmania spp. (8.5%; n = 17/201) and B. burgdorferi s.l. (0.5%; n = 1/201). For D. immitis, 11 out of 201 (5.5%) animals scored positive. At the molecular analysis, 10.4% (n = 21/201) of the samples scored positive for Babesia spp./Hepatozoon spp., followed by Anaplasmataceae (5.0%; n = 10/201) and Rickettsia spp. (3.0%; n = 6/201). All samples were negative for B. burgdorferi s.l. Our data demonstrated the presence of CVBPs in the studied population, with a high seropositivity for Ehrlichia spp. In addition, considering the detection of zoonotic pathogens in dogs and their relationship with people from Quilombola communities, effective control strategies are advocated for minimizing the risk of infection in this socially vulnerable human population and their pets.

Blood Feeding Sources of Nyssomyia antunesi (Diptera: Psychodidae): A Suspected Vector of Leishmania (Kinetoplastida: Trypanosomatidae) in the Brazilian Amazon

Present work aimed to identify blood feeding sources and attempt to detect Leishmania DNA in Nyssomyia antunesi, suspected vector of Leishmania sp., from a park in the urban center of Belém, the capital of Pará State, in the Brazilian Amazon. Entire bodies and gut contents of Ny. antunesi engorged females, previously captured in the urban park with Centers for Disease Control (CDC) light traps and aspiration on tree bases, were subjected to Leishmania and vertebrate DNA detection through amplification of the Leishmania mini-exon and vertebrate cytochrome b (cyt b) gene regions, respectively. The quality of DNA extraction from entire bodies was ensured through amplification of the dipteran cyt b region. The vertebrate cyt b amplicons were sequenced and compared with those available on GenBank. A maximum likelihood phylogenetic tree was constructed to assess the clustering patterns of these sequences. Leishmania DNA was not detected. The sequences of 13 vertebrate cyt b amplicons were considered informative, exhibiting similarity and clustering with the following six vertebrate species: Dasyprocta leporina (1), Cuniculus paca (1), Tamandua tetradactyla (4), Choloepus didactylus (4), Pteroglossus aracari aracari (2), Homo sapiens (1). The samples of D. leporina and C. paca were obtained from the CDC canopy, whereas the others were by aspiration from tree bases. The present results revealed the eclectic and opportunist blood-feeding behavior of Ny. antunesi, with birds and mammals, these last ones acting as potential reservoirs for Leishmania species, distributed throughout the vertical forest strata.

Prevalence and molecular detection of Leishmania spp. in bats from Rio Grande do Sul state, Brazil

This study aimed to detect the occurrence of infection by Leishmania spp.in bats from 34 municipalities of Rio Grande do Sul state (RS; southern Brazil) from 2016 to 2021. A total of 109 bats were provided by the Centro Estadual de Vigilância em Saúde of RS, including six species belonged to Molossidae family, six to Vespertilionidae family, and two to Phyllostomidae family. Leishmania spp. was identified using the nested-PCR method by amplifying the SSU rDNA ribosomal subunit gene into four organ pools: (1) the liver, spleen, and lymph node; (2) heart and lungs; (3) skin; and (4) bone marrow of each bat. Three (3/109, 2.7%) animals tested positive for Leishmania spp. The respective PCR-positive organs came from pools 1 and 3. Two bats (Tadarida brasiliensis) were from the municipality of Canoas, and sequences analysis confirms the species identification as Leishmania infantum. In the third bat (Molossus molossus), from Rio Grande, it was not possible to determine the protozoa species, being considered Leishmania spp. Our results indicate that bats can participate in the biological cycle of Leishmania spp. and perform as host, reservoir, and/or source of infection of the protozoa in different areas of RS. More studies will be needed to elucidate the role of these Chiropteras in the circulation of Leishmania spp. This is the first study reporting the occurrence of Leishmania spp. in bats in Rio Grande do Sul state, southern Brazil.

Leishmania V. braziliensis infection in asymptomatic domestic animals within an endemic region in the Northeast of Brazil

Background:

American cutaneous leishmaniasis is a commonly neglected, vector-borne tropical parasitic disease that is a major public health concern in Brazil. Leishmania (Viannia) braziliensis is the main species associated with the disease. Accurate diagnosis is based on epidemiological surveillance, clinical assessment, and laboratory testing. Leishmania (V.) braziliensis has been detected in several wild and synanthropic mammals. Their epidemiological role has not been entirely elucidated. This study aimed to assess potential L. braziliensis infections in asymptomatic domestic animals, by molecular and serological testing in endemic areas, in the metropolitan region of Recife.

Methods:

Blood samples and conjunctival fluids were collected from 232 animals (canids, felids, equines, and caprines) for the detection of L. braziliensis using molecular tests (conventional and real-time polymerase chain reaction [PCR and qPCR]). For immunological detection, blood samples from 115 dogs were assessed using enzyme-linked immunosorbent assay.

Results:

Real-time quantitative PCR showed positive results for blood and conjunctival samples in all investigated species. The results of the blood and conjunctival samples were 68.2% and 26.9% in Canis familiaris, 100% and 41.7% in Felis catus, 77.3% and 30.8% in Equus caballus/Equus asinus, and 50% and 33.3% in Capra hircus samples, respectively.

Conclusions:

Results from this study adds valuable information to our understanding of the role of asymptomatic domestic animals, L. braziliensis life cycle, and American cutaneous leishmaniasis in Northeast Brazil.

Sand fly bioecological aspects and risk mapping of leishmaniasis by geographical information systems approach in a mineral exploration area of Brazil

Epidemiological studies of leishmaniasis in areas of great human influence and environmental change serve as important tools for the implementation of effective control plans. Mining is currently a major economic activity in Brazil with the municipality of Pains, in the state of Minas Gerais, being one of the main lime producing municipalities in the country. This study aimed to map areas of potential transmission risks within the municipality of Pains using an epidemiological approach in association with the ecological study of sand flies. Twelve samplings carried out between May 2015 and April 2016 collected a total of 12,728 sandflies, comprising 2,854 females (22.42%) and 9,874 males (77.58%), of 20 species belonging to ten genera. The most abundant species was Lutzomyia longipalpis (80%). Leishmania DNA was detected in seven pools of female sand flies with an infection rate of 0.37%. Geoprocessing and the use of maps revealed that vector sand flies are distributed throughout the urban area, as are cases of canine and human leishmaniasis. However, the greatest abundances of sand flies were at sampling points at the border of the urban area. Higher densities of sand flies and the presence of Leishmania DNA may be correlated with extensive degradation by limestone mining. Integrated and multidisciplinary research approaches are necessary to better understand how the impacts of environmental change influence these insect vectors of leishmaniasis.

Unexpectedly high diversity of trypanosomes in small sub-saharan mammals

The extremely species-rich genus Trypanosoma has recently been divided into 16 subgenera, most of which show fairly high host specificity, including the subgenus Herpetosoma parasitizing mainly rodents. Although most Herpetosoma spp. are highly host-specific, the best-known representative, Trypanosoma lewisi, has a cosmopolitan distribution and low host specificity. The present study investigates the general diversity of small mammal trypanosomes in East and Central Africa and the penetration of invasive T. lewisi into communities of native rodents. An extensive study of blood and tissue samples from Afrotropical micromammals (1,528 rodents, 135 shrews, and five sengis belonging to 37 genera and 133 species) captured in the Central African Republic, Ethiopia, Kenya, Malawi, Mozambique, Tanzania, and Zambia revealed 187 (11.2%) trypanosome-positive individuals. The prevalence of trypanosomes in host genera ranged from 2.1% in Aethomys to 37.1% in Lemniscomys. The only previously known trypanosome detected in our dataset was T. lewisi, newly found in Ethiopia, Kenya, and Tanzania in a wide range of native rodent hosts. Besides T. lewisi, 18S rRNA sequencing revealed 48 additional unique Herpetosoma genotypes representing at least 15 putative new species, which doubles the known sequence-based diversity of this subgenus, and approaches the true species richness in the study area. The other two genotypes represent two new species belonging to the subgenera Ornithotrypanum and Squamatrypanum. The trypanosomes of white-toothed shrews (Crocidura spp.) form a new phylogroup of Herpetosoma, unrelated to flagellates previously detected in insectivores. With 13 documented species, Ethiopia was the richest region for trypanosome diversity, which corresponds to the very diverse environments and generally high biodiversity of this country. We conclude that besides T. lewisi, the subgenus Herpetosoma is highly host-specific (e.g., species parasitizing the rodent genera Acomys and Gerbilliscus). Furthermore, several newly detected trypanosome species are specific to their endemic hosts, such as brush-furred mice (Lophuromys), dormice (Graphiurus), and white-toothed shrews (Crocidura).

Oral and Intragastric: New Routes of Infection by Leishmania braziliensis and Leishmania infantum?

Although Leishmania transmission in nature is associated with the bite of an infected sandfly vector, other possible transmission routes are speculated to occur, such as the oral route. We evaluated the possibility of infection by this route in golden hamsters (Mesocricetus auratus) using Leishmania braziliensis (Lb) and Leishmania infantum (Li). Hamsters were exposed to experimental oral or intragastrical infection with axenic promastigotes, besides oral ingestion of a suspension of cultivated macrophages infected with amastigotes, lesion-fed Lutzomyia longipalpis, skin lesion or infective spleen fragment. The parasite's isolation, besides a positive PCR and IFAT, confirmed the intragastric infection by promastigote parasites. The oral ingestion of macrophages infected with L. braziliensis amastigotes was also infective. These results confirmed that Leishmania parasites could infect mammals by the intragastric route through the ingestion of promastigote forms (what can happen after a sandfly ingestion) and by the oral ingestion of infected macrophages (what can happen in nature in a predator-prey interaction). The better understanding of these alternative routes is essential to understand their transmission dynamics in nature. As far as we know, this is the first time that oral and intragastric Leishmania transmission has been experimentally demonstrated, constituting new infection routes, at least for L. infantum and L. braziliensis.