Natural infections of Pintomyia verrucarum and Pintomyia maranonensis by Leishmania (Viannia) peruviana in the Eastern Andes of northern Peru

Epidemiology of Leishmaniasis: Risk factors for its pathology and infection

Leishmaniasis is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. About 20 species of Leishmania are pathogenic to humans, with the specific infecting species playing a crucial role in determining clinical outcomes. There are three main forms of disease: cutaneous, mucocutaneous and visceral leishmaniasis. In addition to the infecting species, it has recently been suggested that parasite strains and genetic factors affect disease manifestation and response to treatment. This suggests that infecting parasites are a crucial risk factor for the pathology of leishmaniasis. These parasites are transmitted by sand flies, of which more than 1000 species have been recorded. However, only approximately 10 % of these species are responsible for transmitting Leishmania, with each sand fly species typically transmitting specific species of Leishmania. Most Leishmania species are zoonotically transmitted by sand flies, with reservoir animals playing a crucial role in disease transmission and endemicity. This aspect of the disease ecology highlights the importance of considering both vectors and reservoir animals in endemic areas as risk factors for leishmaniasis. Our epidemiological studies on leishmaniasis focus mainly on South American countries. This review describes the epidemiological aspects of leishmaniasis in Ecuador and Peru, with a focus on pathological and infectious risks.

Sand Fly Fauna in Urban Parks in the Brazilian Western Amazon: Potential Areas for American Cutaneous Leishmaniasis Transmission

Sand flies are a group of insects (Diptera, Psychodidae, Phlebotominae) in which some species may transmit agents of leishmaniasis. This study aimed to analyze the sand fly fauna in urban parks in Rio Branco, capital of Acre state, addressing its diversity, infection by Leishmania, and food sources in sand fly females. The sand flies were collected with CDC-type automatic light traps installed in three urban parks in Rio Branco: Captain Ciríaco, Horto Florestal and Chico Mendes. For comparison analysis of species richness and diversity between the parks, we analyzed rarefaction and prediction curves. For detection of Leishmania spp., molecular tests were performed by polymerase chain reaction (PCR) using ITS1 as a marker, followed by genetic sequencing. Identification of the blood meal source in engorged females was performed by PCR using a fragment of the cytochrome b gene (cyt b), followed by sequencing and phylogenetic analysis. A total of 2,672 specimens were collected, distributed in 14 genera and 35 species. Of these, Nyssomyia antunesi and Evandromyia walkeri predominated, and important proven and suspected vectors were also found. Horto Florestal was the park with the greatest diversity, richness, and evenness of species, while the Captain Ciríaco presented the lowest diversity and richness. A female of Ny. antunesi was PCR-positive for Leishmania guyanensis. Human blood was the most frequent food source detected, mainly in Ev. walkeri and Ny. antunesi. This research showed that the studied parks of Rio Branco can act as foci for the maintenance of Leishmania, and people who frequent these urban areas may be in risk for contracting leishmaniasis.

Sand Fly Surveillance for Molecular Identification and Characterization of Leishmania and Bartonella Species in Peru

Leishmaniasis and Carrion's disease are endemic neglected diseases in Peru. Both diseases are transmitted by phlebotomine sand flies competent for infection with Leishmania species and Bartonella bacilliformis. In Peru, 149 sand fly species have been identified. Knowledge regarding sand fly species diversity and distribution in leishmaniasis and Carrion's disease transmission areas has grown in the past 2 decades through multiple surveillance efforts in endemic regions, including unexplored low and high jungle areas. Furthermore, molecular testing approaches have been implemented to enhance surveillance of Leishmania and Bartonella species in sand fly populations from these endemic regions. This review emphasizes the importance of entomological surveillance in Peru for the characterization of sand fly species and the discovery of a great diversity of Leishmania and Bartonella species in sand fly populations from Andean and Amazonian regions.

Case Report: A Case of Sporotrichoid Cutaneous Leishmaniasis Caused by Leishmania (Viannia) peruviana

Leishmaniasis is caused by an obligate intracellular protozoa of the genus Leishmania. Its clinical manifestations include cutaneous, mucocutaneous, and visceral forms. Sporotrichoid cutaneous leishmaniasis (SCL) is an atypical and rare form of cutaneous leishmaniasis (CL) reported mainly in the Old World. This case report describes SCL in a Japanese man infected with Leishmania (Viannia) peruviana in Peru. His lesions occurred on both feet, with the left foot lesion being a simple CL that resolved spontaneously. However, the lesion on the right foot did not cure by itself; instead, it progressed centrally along the lymph nodes, eventually forming an SCL. Amastigotes were detected in both feet and genetically identified as L. (V.) peruviana. The lesions gradually resolved after treatment with intravenous liposomal amphotericin B. Here, we report the first case of SCL caused by L. (V.) peruviana.

HRM Accuracy and Limitations as a Species Typing Tool for Leishmania Parasites

High Resolution Melting Analysis (HRM) has been pointed out as a suitable alternative method to detect and identify Leishmania species. Herein, we aimed to evaluate the sensitivity, specificity, accuracy, and limitations of a HSP70-HRM protocol both as a diagnostic scheme applied in clinical samples and as a species typing tool for laboratory research and reference services. Our data reveal the pronounced species-typing potential of the HSP70-HRM in DNA from cultured parasites. For clinical samples, however, we advise caution due to parasite load-dependent accuracy. In light of these findings and considering the importance of parasite load determination for clinical and research purposes, we recommend the integration of the presented typing scheme and the previously published Leishmania quantifying approach as combined tools for clinicians, surveillance, and research.

Morphological description of Pintomyia (Pifanomyia) veintemillasi n. sp., a new sand fly species from the sub-Andean region of Bolivia

Background

Most sand fly species are located in the Americas; some act as vectors of leishmaniasis and other human diseases. In Bolivia, about 25% of Neotropical species have been identified, and only a few have been implicated as vectors of cutaneous and visceral leishmaniasis. A new species of anthropophilic sand fly from the sub-Andean region of Alto Beni is described herein.

Methods

A large systematic entomological survey was carried out in a subtropical humid forest located in the Marimonos mountain range, at around 900 m altitude, in the municipality of Palos Blancos, Sud Yungas Province, Department of La Paz, Bolivia. Sand flies were captured over a period of 26 months between January 1982 and February 1984, at the ground and canopy level, using both CDC light traps and protected human bait. A total of 24,730 sand flies were collected on the ground, distributed in 16 species, and 3259 in the canopy, with eight species. One of these species was labeled as Pintomia (Pifanomyia) nevesi, although certain morphological features allowed us to doubt that it was that taxon. To define the identity of this sand fly, a re-evaluation (this work) was recently carried out through morphological analyses and measurements of the available specimens mounted on Euparal, previously labeled as Pi. (Pif.) nevesi.

Results

Based on the morphological traits and measurements, the re-evaluated specimens were definitively identified as a new sand fly species, Pintomyia (Pifanomyia) veintemillasi, closely related to Pi. (Pif.) nevesi and Pintomyia (Pifanomyia) maranonensis within the Evansi series. This new sand fly was the third most numerous anthropophilic species at the floor (6.2%) and the second most numerous anthropophilic at the canopy (35.1%).

Conclusions

A new anthropophilic sand fly species is described as Pi. (Pif.) veintemillasi n. sp. This sand fly species was caught at about 900 m altitude in the Marimonos mountain range, a highly endemic area for cutaneous and mucosal leishmaniasis due to Leishmania (Viannia) braziliensis. Therefore, this species could be involved in the leishmaniasis transmission in the sub-Andean foothills of Alto Beni, Department of La Paz, Bolivia.

Graphical Abstract

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.