Invasive Species as Hosts of Zoonotic Infections: The Case of American Mink (Neovison vison) and Leishmania infantum

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.

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 epidemiological survey of Leishmania infantum in the domestic ferret (Mustela putorius furo) in a canine leishmaniosis endemic area using serology and PCR

BACKGROUND

Leishmaniosis, a vector-borne disease caused by Leishmania infantum, is one of the most important parasitic zoonoses in Europe. The transmission cycle of leishmaniosis is maintained by both domestic and wild animals. However, few data are available on the role of wild mammals in transmitting the parasite in the European Mediterranean basin. As feline leishmaniosis, diagnosis of the infection in ferrets can be a challenge, the use of different serological and molecular methods combined is a recommended approach. Our aim was to investigate the prevalence of infection of L. infantum in apparently healthy domestic ferrets (Mustela putorius furo) in an endemic region of Spain (Community of Valencia), using serological and molecular methods and to evaluate the results comparing the different techniques.

METHODS

The prevalence of Leishmania infection was studied in domestic ferrets. Blood was collected from each animal for serology and molecular analysis. Two serological methods, enzyme-linked immunosorbent assay (ELISA) and western blot (WB), were used for the detection of L. infantum antibodies, and real-time polymerase chain reaction (qPCR) was used for the detection of L. infantum DNA.

RESULTS

Blood samples from 102 apparently healthy ferrets were analyzed. In the serological study, 25.5% of the animals tested positive by western blot, and 9.0% by enzyme-linked immunosorbent assays. The seroprevalence of L. infantum infection, based on a positive result in any serological test, was 28.4% (95% confidence interval [CI] 20.6-S37.9%). No kinetoplast DNA (kDNA) was detected by qPCR in peripheral blood samples from the ferrets tested.

CONCLUSIONS

The immunological response revealed by these tests indicates that the ferrets are exposed to repeated inoculations with the endemic parasite L. infantum. Although the low population of domestic ferrets means their reservoir potential is limited in the absence of a primary host, it would be of interest to carry out further studies using xenodiagnosis to determine whether they are accidental or reservoir host species capable of spreading infection.

Cryobanking European Mink (Mustela lutreola) Mesenchymal Stem Cells and Oocytes

The European mink (Mustela lutreola) is one of Europe’s most endangered species, and it is on the brink of extinction in the Iberian Peninsula. The species’ precarious situation requires the application of new ex situ conservation methodologies that complement the existing ex situ and in situ conservation measures. Here, we report for the first time the establishment of a biobank for European mink mesenchymal stem cells (emMSC) and oocytes from specimens found dead in the Iberian Peninsula, either free or in captivity. New emMSC lines were isolated from different tissues: bone marrow (emBM-MSC), oral mucosa (emOM-MSc), dermal skin (emDS-MSC), oviduct (emO-MSc), endometrium (emE-MSC), testicular (emT-MSC), and adipose tissue from two different adipose depots: subcutaneous (emSCA-MSC) and ovarian (emOA-MSC). All eight emMSC lines showed plastic adhesion, a detectable expression of characteristic markers of MSCs, and, when cultured under osteogenic and adipogenic conditions, differentiation capacity to these lineages. Additionally, we were able to keep 227 Cumulus-oocyte complexes (COCs) in the biobank, 97 of which are grade I or II. The European mink MSC and oocyte biobank will allow for the conservation of the species’ genetic variability, the application of assisted reproduction techniques, and the development of in vitro models for studying the molecular mechanisms of infectious diseases that threaten the species’ precarious situation.

Nutritional Modulation of the Immune Response Mediated by Nucleotides in Canine Leishmaniosis

Leishmaniasis is an emerging, uncontrolled, and neglected zoonotic disease. Climate change is contributing to its ongoing global expansion. The dog is the main reservoir; hence the importance of implementing effective treatment, prevention, and control measures in this animal species to protect public health. However, although the standard treatment for canine leishmaniosis (CanL) is effective, it does not provide full parasitological clearance, and side effects and drug resistance have been described. The host's immune system plays a key role in the establishment and evolution of leishmaniasis. Dietary nucleotides modulate the immune response and, given their reported efficacy and safety in sick and clinically healthy Leishmania-infected dogs and because they represent a sustainable option with no associated side effects or resistance, they could be included within the prevention, treatment, and control strategies for leishmaniasis. This article briefly summarizes the scientific literature on CanL management, including unresolved issues, and reviews the scientific evidence on immunomodulatory effects of dietary nucleotides in different animal species. It also proposes a CanL management algorithm, including nucleotides. It is concluded that nutritional modulation of the immune response with nucleotides can contribute to better management of leishmaniasis following a One Health approach, especially in the COVID-19 era.

Editorial for the Special Issue "Parasitic Diseases from Wild Animals with Emphasis on Zoonotic Infections"

The present Editorial intends to briefly describe the findings published in the Special Issue, "Parasitic diseases from wild animals with an emphasis on zoonotic infections". Prevalence data or diagnostic techniques were the focus of several zoonotic parasites transmitted from wildlife, including the protozoa Toxoplasma, Cryptosporidium, Giardia, Blastocystis and Leishmania, and the helminths Echinococcus and Anisakis.