High prevalence of pathogenic Leptospira in alien American mink (Neovison vison) in Patagonia

Confirmation of the invasive American mink (Neogale vison) as carrier of Mycobacterium bovis in southern Chile

Bovine tuberculosis (bTB) is a chronic infectious-contagious disease with worldwide distribution, caused by the zoonotic pathogen Mycobacterium bovis. It is believed that the existence of wild cycles may hamper the success of bTB control strategies worldwide, where wildlife species could be reservoirs of this bacterial agent across their native (e.g., European badgers, wild boars) or non-indigenous (e.g., brushtail possum in New Zealand) ranges. However, further studies are required to understand the potential risk posed by non-native wildlife in becoming carriers of M. bovis in other neglected latitudes, such as the Southern Cone of South America. In this study, we performed a specific M. bovis-RD4 real-time PCR (qPCR) assay to detect bacterial DNA in tissues from the invasive American mink (Neogale vison) in Los Ríos region, Chile. We detected M. bovis DNA in blood samples collected from 13 out of 186 (7 %) minks with known sex and age. We did not find any significant differences in bacterial DNA detection according to mink sex and age. We found that 92 % (12/13) of specimens were positive in lung, 39 % (5/13) in mediastinal lymph node, and 15 % (2/13) in mesenteric lymph node, which suggest that both respiratory and digestive pathways as possible routes of transmission between infected hosts and minks. Our study is the first report on M. bovis molecular detection in invasive minks in an area where the largest cattle population in the country is located. Furthermore, this area is characterized by a low within-herd prevalence of M. bovis infection in cattle, with a relatively low number of infected herds, and so far, no attempts at eradicating the disease have been successful.

Basic Aspects and Epidemiological Studies on Leptospirosis Carried Out in Animals in Chile: A Bibliographic Review

Leptospirosis is an important zoonosis worldwide. This disease affects numerous animal species, some of them are classified as "maintenance hosts", and others are categorized as "incidental hosts". Humans are at risk of becoming infected by having contact with domestic and wild animals. In this paper, general aspects of the etiology and transmission of leptospirosis are addressed, data regarding the clinical presentation of the pathology in humans and animals are also presented, and the results of some epidemiological studies on leptospirosis carried out in Chile in different animal species and humans are summarized through a bibliographic review of the literature. The research on domestic canines and horses stands out in terms of their number in the country, with prevalences between 12.0% and 59.1% in dogs and from 23.3% to 65.4% in equids. Studies have been performed on domestic felines in recent years with frequencies ranging from 3.0% to 25.2%, as well as on wild animals (mainly in mammals). In pigs, cattle, sheep, and goats, the information is scarce, with little updated research dating back several decades and variable prevalence rates, which are generally high, except for in sheep. Leptospirosis is a disease of varied etiology in terms of infecting species, serovars and serogroups, which influences its epidemiology, and its prevalence is variable in different animals. An increase in the awareness given to this pathology in human and veterinary public health is required, as well as more scientific studies in Chile, to update the existing knowledge.

LEPTOSPIRA, PARVOVIRUS, AND TOXOPLASMA IN THE NORTH AMERICAN RIVER OTTER (LONTRA CANADENSIS) IN NORTH CAROLINA, USA

The North American river otter (Lontra canadensis) is the largest mustelid in North Carolina, US, and was once extirpated from the central and western portions of the state. Over time and after a successful reintroduction project, otters are now abundant and occur throughout North Carolina. However, there is a concern that diseases may have an impact on the otter population, as well as on other aquatic mammals, either through exposure to emerging diseases, contact with domestic animals such as domestic cats (Felis catus), or less robust condition of individuals through declines in water quality. We tested brain and kidney tissue from harvested otters for the pathogens that cause leptospirosis, parvovirus, and toxoplasmosis. Leptospirosis and toxoplasmosis are priority zoonoses and are maintained by domestic and wild mammals. Although parvovirus is not zoonotic, it does affect pets, causing mild to fatal symptoms. Across the 2014-15 and 2015-16 trapping seasons, we tested 220 otters (76 females, 144 males) using real-time PCR for Leptospira interrogans, parvovirus, and Toxoplasma gondii. Of the otters tested, 1% (3/220) were positive for L. interrogans, 19% (41/220) were positive for parvovirus, and 24% (53/220) were positive for T. gondii. Although the pathogens for parvovirus and toxoplasmosis are relatively common in North Carolina otters, the otter harvest has remained steady and the population appears to be abundant and self-sustaining. Therefore, parvovirus and toxoplasmosis do not currently appear to be negatively impacting the population. However, subsequent research should examine transmission parameters between domestic and wild species and the sublethal effects of infection.

New insights on the infection of pathogenic Leptospira species in American mink (Neovison vison) in southern Chile

Leptospirosis is a zoonosis of global distribution, caused by the infection of pathogenic Leptospira, a group of bacteria capable of infecting both domestic and wild animals. Mink (Neovison vison) in southern Chile is recognized as a wild and synanthropic rodent predator (among various other prey), and Leptospira infection in them can be acquired through contact with the pathogen in the environment or by eating infected prey. Thus, the aim of this study was to provide more specifics regarding the source of the infection for the American mink under the conditions of Southern Chile. Minks were captured in the Los Ríos region, southern Chile, in an area with well-developed dairy farming. Two areas were selected for mink trapping, one with a high degree of dairy farming and a second with a low degree of dairy farming. Within them, 16 study sites were visited, and 45 American mink were trapped and euthanized to obtain kidney tissue and blood serum samples for bacteria isolation and determination of antibodies titers, respectively. Molecular characterization of the isolated strains was performed. Three minks from sites of high-dairy farming industry and only one from sites with low-degree dairy farming were detected as infected through molecular confirmation. This study shows evidence that confirms previous findings made in southern Chile, regarding mink as host of Leptospira interrogans serovar Hardjo-prajitno associated to cattle-farming areas. However, typing information ( Leptospira interrogans Copenhageni and Icterohaemorrhagiae ) suggests that the consumption of rodents may also be a potential source of infection.

Molecular survey of Bartonella spp. and haemoplasmas in American minks (Neovison vison)

The aim of this study was to perform a molecular survey and characterize Bartonella spp. and haemotropic Mycoplasma (haemoplasmas) in invasive American minks (Neovison vison) from Southern Chile. Additionally, we addressed risk factors for positivity in both groups of agents. Blood and/or tissue samples from 246 minks were analysed by qPCR targeting the nuoG gene for Bartonella spp. and conventional (c)PCR for 16S rRNA for haemotropic Mycoplasma spp. nuoG qPCR-positive Bartonella spp. samples were submitted to cPCR assays (ITS, ribC, gltA, rpoB, pap-31 and ftsZ genes) to perform phylogenetic inferences. Haemotropic Mycoplasma spp. 16S-positive samples were further amplified by cPCR targeting RNaseP gene (160-210 bp) and by two overlapping 16S rRNA cPCR assays to amplify a larger portion of the gene (1,200bp) for phylogenetics. Bartonella DNA was detected in 8.9% of minks (22/246). Out of 22 nuoG qPCR-positive samples, one and two showed positive results in cPCR assays based on ITS and ribC, respectively. Consistent sequencing results were obtained for only one ITS sample (464 bp sequence), which shared 99.6% identity with B. clarridgeiae. Two per cent of minks (5/246) were positive for 16S rRNA haemotropic Mycoplasma-cPCR assay. Two concatenated sequences of 16S rRNA (1,176 and 1,230 bp) were obtained: one sample shared 97.87% identity with haemotropic Mycoplasma sp. from a wild rodent, and the other 96.49% identity with 'Candidatus Mycoplasma haematoparvum' from a dog. All BLAST results were supported by phylogenetic analysis. One haemoplasma RNase P sequence shared 94.86% identity with Mycoplasma haemofelis from a cat. No risk factors for PCR positivity were identified. In a nutshell, Bartonella clarridgeiae and a potentially novel haemoplasma closely related to haemoplasmas previously reported in rodents, dogs, domestic and wild cats were described for the first time in American minks.

Evidence of Pathogenic Leptospira Infection in a Free-ranging Andean Fox (Lycalopex culpaeus) from Central Chile

We found evidence of infection and shedding of Leptospira serovars Ballum and Canicola in the Andean fox (Lycalopex culpaeus) in Chile. We used PCR to demonstrate the presence of Leptospira DNA and microagglutination tests to identify serovars.

Serology and protein electrophoresis for evidence of exposure to 12 mink pathogens in free-ranging American mink (Neovison vison) in Argentina

BACKGROUND

Basic pathologic characteristics for farmed minks were previously reported worldwide. However, its status in the wild has not been studied in detail.

OBJECTIVE

Serology and electrophoresis were carried out for evidence of exposure to 12 mink pathogens on two different locations.

ANIMALS AND METHODS

Serology was done in 87 wild minks by reference techniques against Toxoplasma gondii, Encephalitozoon cuniculi, Neospora caninum, Brucella abortus, Mycobacterium bovis, Leptospira interrogans, canine distemper virus (CDV), canine adenovirus (CAV), canine parvovirus (CPV), rabies virus (RV), Influenza A virus (FLUAV) and Aleutian disease virus (ADV). Hypergammaglobulinemia, the ADV main clinical feature, was determined by conventional electrophoresis.

RESULTS

Seventy-one percent of the 87 sera had antibodies against one or more pathogens. ADV accounted for the highest seroprevalence (29%), followed by T. gondii (26%), L. interrogans (14%), M. bovis (12%), B. abortus (9%), N. caninum (3%), CPV (3%) and CDV (2%). Seroprevalence was influenced by location but not sex or age. Additionally, 16% of the seropositive samples for ADV had gammaglobulin levels >40.0 g/L. Antibody titers for CDV and CPV were low and difficult to interpret as almost all these cases had borderline concentrations.

CONCLUSION

A cautious interpretation of the results is urged as the epidemiological role of the wild mink is largely unexplored for most of these agents. Nevertheless, the information may be clinically relevant..