Detection of Leishmania DNA in wild foxes and associated ticks in Patagonia, Argentina, 2000 km south of its known distribution area

Is leishmaniasis the new emerging zoonosis in the world?

Leishmania is a genus of parasitic protozoa that causes a disease called leishmaniasis. Leishmaniasis is transmitted to humans through the bites of infected female sandflies. There are several different species of Leishmania that can cause various forms of the disease, and the symptoms can range from mild to severe, depending on species of Leishmania involved and the immune response of the host. Leishmania parasites have a variety of reservoirs, including humans, domestic animals, horses, rodents, wild animals, birds, and reptiles. Leishmaniasis is endemic of 90 countries, mainly in South American, East and West Africa, Mediterranean region, Indian subcontinent, and Central Asia. In recent years, cases have been detected in other countries, and it is already an infection present throughout the world. The increase in temperatures due to climate change makes it possible for sandflies to appear in countries with traditionally colder regions, and the easy movement of people and animals today, facilitate the appearance of Leishmania species in new countries. These data mean that leishmaniasis will probably become an emerging zoonosis and a public health problem in the coming years, which we must consider controlling it from a One Health point of view. This review summarizes the prevalence of Leishmania spp. around the world and the current knowledge regarding the animals that could be reservoirs of the parasite.

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.

Detection of Leishmania sp. kDNA in questing Ixodes ricinus (Acari, Ixodidae) from the Emilia-Romagna Region in northeastern Italy

To date, sand flies (Phlebotominae) are the only recognized biological vectors of Leishmania infantum, the causative agent of human visceral leishmaniasis, which is endemic in the Mediterranean basin and also widespread in Central and South America, the Middle East, and Central Asia. Dogs are the main domestic reservoir of zoonotic visceral leishmaniasis, and the role of secondary vectors such as ticks and fleas and particularly Rhipicephalus sanguineus (the brown dog tick) in transmitting L. infantum has been investigated. In the present paper, the presence of Leishmania DNA was investigated in questing Ixodes ricinus ticks collected from 4 rural areas included in three parks of the Emilia-Romagna Region (north-eastern Italy), where active foci of human visceral leishmaniasis have been identified. The analyses were performed on 236 DNA extracts from 7 females, 6 males, 72 nymph pools, and 151 larvae pools. Four samples (1.7%) (i.e., one larva pool, 2 nymph pools, and one adult male) tested positive for Leishmania kDNA. To the best of our knowledge, this is the first report of the presence of Leishmania kDNA in questing I. ricinus ticks collected from a rural environment. This finding in unfed larvae, nymphs, and adult male ticks supports the hypothesis that L. infantum can have both transstadial and transovarial passage in I. ricinus ticks. The potential role of I. ricinus ticks in the sylvatic cycle of leishmaniasis should be further investigated.

Large-scale survey for canine vector-borne parasites in free-ranging dogs and foxes from six diverse bioclimatic regions of Chile

Chile is a large country with a marked range of climate conditions that make it an ideal scenario for the study of vector-borne parasites (VBPs); however, knowledge about their distribution is limited to a few confined areas of this country. The presence of Hepatozoon spp., piroplasmids, Leishmania spp. and filarioids was investigated through molecular and serological methods in blood and serum samples of 764 free-ranging rural dogs, 154 Andean foxes (Lycalopex culpaeus), and 91 South American grey foxes (Lycalopex griseus) from six bioclimatic regions across Chile. Hepatozoon spp. DNA was exclusively detected in foxes (43% prevalence), including sequences closely related to Hepatozoon felis (24.1%; only Andean foxes), Hepatozoon americanum (16.2%; only grey foxes), and Hepatozoon canis (1.25%; in one grey fox). Risk factor assessment identified a higher probability of Hepatozoon infection in juvenile foxes. DNA of piroplasmids was detected in 0.7% of dogs (Babesia vogeli) but in no fox, whilst antibodies against Babesia sp. were detected in 24% of the dogs and 25% of the foxes, suggesting a wider circulation of canine piroplasmids than previously believed. A positive association between the presence of antibodies against Babesia and high Rhipicephalus sanguineus sensu lato burden was observed in dogs. Leishmania spp. DNA and antibodies were detected in 0.8% and 4.4% of the dogs, respectively. Acanthocheilonema reconditum was the only blood nematode detected (1.5% of the dogs and no fox). Differences in prevalence among bioregions were observed for some of the VBPs. These results expand our knowledge about the occurrence of vector-borne parasites in Chile, some of which are firstly reported herein. This information will facilitate the diagnosis of vector-borne diseases in domestic dogs and improve the control measures for both domestic and wild canids.

A Systematic Review (1990-2021) of Wild Animals Infected with Zoonotic Leishmania

Leishmaniasis are neglected diseases caused by several species of Leishmania that affect humans and many domestic and wild animals with a worldwide distribution. The objectives of this review are to identify wild animals naturally infected with zoonotic Leishmania species as well as the organs infected, methods employed for detection and percentage of infection. A literature search starting from 1990 was performed following the PRISMA methodology and 161 reports were included. One hundred and eighty-nine species from ten orders (i.e., Carnivora, Chiroptera, Cingulata, Didelphimorphia, Diprotodontia, Lagomorpha, Eulipotyphla, Pilosa, Primates and Rodentia) were reported to be infected, and a few animals were classified only at the genus level. An exhaustive list of species; diagnostic techniques, including PCR targets; infected organs; number of animals explored and percentage of positives are presented. L. infantum infection was described in 98 wild species and L. (Viania) spp. in 52 wild animals, while L. mexicana, L. amazonensis, L. major and L. tropica were described in fewer than 32 animals each. During the last decade, intense research revealed new hosts within Chiroptera and Lagomorpha. Carnivores and rodents were the most relevant hosts for L. infantum and L. (Viannia) spp., with some species showing lesions, although in most of the studies clinical signs were not reported.

Trypanosomatid Infections among Vertebrates of Chile: A Systematic Review

We present a review on the natural infection by trypanosomatids of nonhuman vertebrates in Chile, aiming to synthesize and update the knowledge on the diversity of trypanosomatids infecting native and alien vertebrate species. To this end, we conducted a systematic review of literature records published from 1900 to April 2020 on four databases, focusing on the 21 genera of trypanosomatids and Chile. The methods and findings of our review have been based on the preferred reporting items for systematic reviews and meta-analysis (prisma) checklist. We found 29,756 records but only 71 presented relevant information for this review. Overall, there are only two reported trypanosomatid genera infecting vertebrate species in Chile, the genera Trypanosoma and Leishmania. The former is mostly represented by Trypanosoma cruzi (90% of the total records) and to a much lesser extent by Trypanosoma avium, Trypanosoma humboldti, Trypanosoma lewisi, and a couple of unidentified trypanosomatids. A total of 25 mammals have been reported as being infected by T. cruzi, including 14 native and 11 alien species from Orders Artiodactyla, Carnivora, Chiroptera, Didelphimorphia, Lagomorpha, Perissodactyla, and Rodentia. Extensive screening studies using new analytical tools are necessary to grasp the whole potential diversity of trypanosomatid species infecting vertebrates in Chile.

Epidemiological evaluation of Leishmania infantum zoonotic transmission risk in the recently established endemic area of Northwestern Italy

Leishmania infantum infection had been expanding into new areas due to changes in vector and host biology. Zoonotic visceral leishmaniasis has become endemic in previously unsuitable areas as vectors find favourable climatic conditions and an increasing number of reservoir dogs are moved between traditionally and new endemic areas. Monitoring vector and disease expansion in areas of recent colonization is needed to understand transmission mechanisms and patterns of disease establishment. Here, we studied the infection status of 815 human blood donors and of 803 sympatric dogs from five, newly endemic, areas in Northwestern Italy. In autochthonous dogs, the seroprevalence of anti-L. infantum antibodies, recorded by Western blot, reached 42.22%, while in humans, the seroprevalence was of 16.81%. No significant correlation between the infection status of dogs and that of their human owners was found, but L. infantum infection was recorded in the different study areas with significant levels of diversity. Restriction fragment length polymorphism showed a high genetic variability of the circulating strains and gave useful insights on patterns of disease establishment into a naïve area.

Influences of climate change on the potential distribution of Lutzomyia longipalpis sensu lato (Psychodidae: Phlebotominae)

This study explores the present day distribution of Lutzomyia longipalpis in relation to climate, and transfers the knowledge gained to likely future climatic conditions to predict changes in the species' potential distribution. We used ecological niche models calibrated based on occurrences of the species complex from across its known geographic range. Anticipated distributional changes varied by region, from stability to expansion or decline. Overall, models indicated no significant north-south expansion beyond present boundaries. However, some areas suitable both at present and in the future (e.g., Pacific coast of Ecuador and Peru) may offer opportunities for distributional expansion. Our models anticipated potential range expansion in southern Brazil and Argentina, but were variably successful in anticipating specific cases. The most significant climate-related change anticipated in the species' range was with regard to range continuity in the Amazon Basin, which is likely to increase in coming decades. Rather than making detailed forecasts of actual locations where Lu. longipalpis will appear in coming years, our models make interesting and potentially important predictions of broader-scale distributional tendencies that can inform heath policy and mitigation efforts.