Detection of Toxoplasma gondii (Types I, II, III and 12) and Sarcocystis spp. in the brains of river otter (Lontra canadensis) from Alberta, Canada

Toxoplasma gondii and Sarcocystis spp. are globally distributed coccidian parasites infecting endothermic vertebrates. Toxoplasma gondii is zoonotic, with widespread global prevalence in humans, domestic animals, and wildlife. Sarcocystis is a related and diverse genus, with species that use a range of definitive and intermediate hosts. In intermediate hosts, these tissue dwelling coccidians can be asymptomatic or cause disease through neural, hepatic, and transplacental infections. Semiaquatic mammals such as the North American river otter (Lontra canadensis) are at high risk of exposure to T. gondii and Sarcocystis spp. due to terrestrial runoff into freshwater environments. Their high trophic position and dual habitat use make them excellent sentinel species to monitor the presence of food and waterborne pathogens in ecosystems. Brain tissue was sampled from 89 river otters in Alberta, Canada. DNA of T. gondii was detected in 34 % of otters using magnetic capture sequence-specific DNA extraction and qPCR. Genotypes of T. gondii were identified using nested PCR and sequencing of the GRA6 and SAG2 genes, and included the most common clonal lineages in North America, Types I, II, and III, as well as Type-12 (X/A), which is highly pathogenic in sea otters. DNA of Sarcocystis spp. was detected in brain lysates of 30 % of otters via conventional PCR with primers targeting ITS1 and 18S ribosomal regions, and sequencing revealed S. lutrae and a species most closely related to, but distinct from, S. kitikmeotensis. This study suggests that river otters are exposed trophically to T. gondii shed by felids, and at least 2 species of Sarcocystis shed by unknown definitive hosts. Highly pathogenic S. neurona was not detected in this population, likely reflecting the absence of possum definitive hosts in northern Canada. The potential effects of T. gondii and Sarcocystis spp. on behaviour, health, and reproduction of river otters warrant further investigation.

Molecular identification of Sarcocystis neurona in tissues of wild boars (Sus scrofa) in the border region between Brazil and Uruguay

Sarcocystis neurona, owing to its clinical importance in domestic animals, is currently one of the most studied agents, presenting a wide range of intermediate hosts that have not yet been described, mainly in wild fauna. Thus, the aim of this study was to describe the detection and molecular detection of S. neurona by amplification of the 18S rRNA region in the tissues of wild boars killed by boar control program in border Brazil Uruguay. A total of 79 samples of DNA from wild boar tissues from the LADOPAR/UFSM sampling bank were used, with Nested-PCR reactions being performed for amplification of the 18S rRNA region and the expected final product of 290 bp. Subsequently, the positive samples were subjected to restriction fragment length polymorphism (RFLP) technique with the restriction enzymes DdeI and HPAII. A second semi-Nested reaction was performed to obtain a larger sequence of nucleotides with amplification of the 18S region and the expected final product of 500 bp for S. neurona and Nested amplification ITS1 with product final of 367 pb. In 32 samples, it was possible to detect S. neurona both by nested Nested-PCR reaction and RFLP, and the presence of the agent was confirmed by sequencing, corresponding to 40.51% of the total tissues evaluated. This is the first report of the occurrence of this species of Sarcocystis in wild boars, and further studies evaluating the role of these animals as intermediate hosts, and in the epidemiology of this protozoan are necessary, as well as verifying the risk factors for infection.

Recent epidemiologic and clinical Toxoplasma gondii infections in wild canids and other carnivores: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, and genetic diversity of T. gondii in wild canids and other carnivores for the past decade. Seroprevalence estimates of T. gondii worldwide were tabulated for each host. Seroprevalence in wild foxes was very high compared with farmed Arctic foxes. Economic and public health aspects of some of the carnivore species raised for fur and meat (raccoon dogs, mink) are discussed. Diagnostic efficacies of different serological methods and PCR methods are discussed. Clinical toxoplasmosis was observed mainly in carnivores concurrently infected with immunosuppressive Canine Distemper Virus infection. Abortion and blindness were noted in mink. Genetic diversity of isolates using DNA derived from 162 (89 viable T. gondii isolates and 73 DNA extracted from tissues) of wild carnivores from several countries is discussed. However, 69 of the 162 T. gondii isolates were strains from USA and these were genetically diverse with predominance of ToxoDB genotypes #4 and #5 (haplogroup 12). Only limited information is available concerning genotyping of T. gondii isolates from other countries; none of the 93 T. gondii isolates from other countries (Brazil, China, France, Grenada) were haplogroup 12.

Using reintroduction to elucidate breeding system, breeding phenology, and infanticide for a solitary carnivore (fisher, Pekania pennanti)

Breeding systems affect the timing of reproduction, spacing patterns and social organization, individual fitnesses, and population sizes. For many species, information on breeding systems and mating is limited or untested in wild populations, resulting in management actions that are incompletely informed. We used photographic data collected on a reintroduced fisher (Pekania pennanti (Erxleben, 1777)) population in northern California, USA, to test hypotheses about the breeding system, the timing of breeding, and the potential for male infanticide. We documented fishers of both sexes breeding with multiple partners in the same year, demonstrating polygynandry. We use logistic and linear regression to evaluate the timing and frequency of male visitation at 262 reproductive dens used by 50 individual females. Of 46 documented copulations and 577 male visits, 100% and 95%, respectively, occurred while females had kits in their natal dens. Seventy-five percent of documented male visits occurred before 31 March and 95% occurred before 17 April. Observed breeding occurred within 3.1 ± 1.6 days (mean ± SD) of locating females’ natal dens. We found no evidence for male-directed infanticide. Our results add precision to the timing of the reproductive cycle and provide the first descriptions of male–female interactions for wild fishers.

SEROSURVEY, HEMATOLOGY, AND CAUSES OF MORTALITY OF FREE-RANGING AMERICAN MARTENS ( MARTES AMERICANA) IN MICHIGAN

  To better understand the clinical pathology, diseases, and causes of mortality of reintroduced American martens ( Martes americana) in Michigan, a study was conducted from 2011 to 2015 in the Upper and Lower Peninsulas of Michigan. Samples obtained from live trapping ( n = 58) or harvested carcasses ( n = 34) were serologically tested for select pathogens. Antibodies against Toxoplasma gondii and canine distemper virus were detected in 58 and 3.4% of samples, respectively. All samples were seronegative for Leptospira spp. and negative for Dirofilaria immitis antigen. Urine samples tested for Leptospira spp. via immunofluorescent antibody assay ( n = 7), polymerase chain reaction ( n = 6) , or both ( n = 3) were all negative. Parvovirus DNA was detected in 9.1% of small intestine samples ( n = 22) collected from carcasses and in 3.7% of fecal samples ( n = 27) collected during live trapping. Complete blood counts ( n = 64) and serum biochemistries ( n = 63) were obtained from 49 live-trapped martens. Biochemical parameters found to be significantly different ( P < 0.05) between genders were calcium, creatinine, glucose, and phosphorus. There was no significant difference between genders for any hematologic parameter. Significant differences ( P < 0.05) between summer and winter seasons were found in total estimated white blood cell count, neutrophils, lymphocytes, monocytes, alkaline phosphatase, bicarbonate, calcium, creatinine, globulin, glucose, phosphorus, potassium, sodium, and total protein. There was no significant difference in blood cell count or serum biochemistry values between radio-collared ( n = 17) and noncollared ( n = 47) martens. Animals seropositive for T. gondii were found to have significantly higher ( P < 0.05) eosinophil and globulin levels than seronegative animals. The primary natural cause for mortality of radio-collared American martens was predation. Histologic examinations revealed a high percentage (60%) of martens with verminous or granulomatous pneumonia.

Molecular identification of Sarcocystis lutrae (Apicomplexa: Sarcocystidae) in muscles of five species of the family Mustelidae

Carnivores usually act as definitive hosts of Sarcocystis species. However, the number of reports on sarcocyst formation in musculature of predators is on the increase. In the present study, muscle samples of 68 mustelids collected in Lithuania were examined for sarcocysts of Sarcocystis species. Sarcocysts were detected in diaphragm, tongue and limb muscles of ten animals (14.7%) but were not discovered in the heart. Based on 18S rDNA, 28S rDNA, cox1 and ITS1 sequence analysis, Sarcocystis lutrae was identified in three American minks (Neovison vison), two beech martens (Martes foina), three Eurasian badgers (Meles meles), one Eurasian otter (Lutra lutra) and one European polecat (Mustela putorius). The intraspecific variability of this Sarcocystis species was determined only in ITS1 region. Based on the phylogenetic analysis, no clear separation of S. lutrae by intermediate hosts or geographical locations was established. This paper represents the first identification of S. lutrae in the American mink, the beech marten and the European polecat. Current results indicate that S. lutrae is a common species in the muscles of various European mustelids.

Endoparasites of American marten (Martes americana): Review of the literature and parasite survey of reintroduced American marten in Michigan

The American marten (Martes americana) was reintroduced to both the Upper (UP) and northern Lower Peninsula (NLP) of Michigan during the 20th century. This is the first report of endoparasites of American marten from the NLP. Faeces from live-trapped American marten were examined for the presence of parasitic ova, and blood samples were obtained for haematocrit evaluation. The most prevalent parasites were Capillaria and Alaria species. Helminth parasites reported in American marten for the first time include Eucoleus boehmi, hookworm, and Hymenolepis and Strongyloides species. This is the first report of shedding of Sarcocystis species sporocysts in an American marten and identification of 2 coccidian parasites, Cystoisospora and Eimeria species. The pathologic and zoonotic potential of each parasite species is discussed, and previous reports of endoparasites of the American marten in North America are reviewed.

Molecular characterisation of Sarcocystis lutrae n. sp. and Toxoplasma gondii from the musculature of two Eurasian otters (Lutra lutra) in Norway

Sarcocysts were detected in routinely processed histological sections of skeletal muscle, but not cardiac muscle, of two adult male otters (Lutra lutra; Mustelidae) from northern Norway following their post-mortem examination in 1999 and 2000. The sarcocysts were slender, spindle-shaped, up to 970 μm long and 35-70 μm in greatest diameter. The sarcocyst wall was thin (∼ 0.5 μm) and smooth with no visible protrusions. Portions of unfixed diaphragm of both animals were collected at the autopsies and kept frozen for about 14 years pending further examination. When the study was resumed in 2013, the thawed muscle samples were examined for sarcocysts under a stereo microscope, but none could be found. Genomic DNA was therefore extracted from a total of 36 small pieces of the diaphragm from both otters, and samples found to contain Sarcocystidae DNA were used selectively for PCR amplification and sequencing of the nuclear 18S and 28S ribosomal (r) RNA genes and internal transcribed spacer 1 (ITS1) region, as well as the mitochondrial cytochrome b (cytb) and cytochrome c oxidase subunit 1 (cox1) genes. Sequence comparisons revealed that both otters were infected by the same Sarcocystis sp. and that there was no genetic variation (100 % identity) among sequenced isolates at the 18S and 28S rRNA genes (six identical isolates at both loci) or at cox1 (13 identical isolates). PCR products comprising the ITS1 region, on the other hand, had to be cloned before sequencing due to intraspecific sequence variation. A total of 33 clones were sequenced, and the identities between them were 97.9-99.9 %. These sequences were most similar (93.7-96.0 % identity) to a sequence of Sarcocystis kalvikus from the wolverine in Canada, but the phylogenetic analyses placed all of them as a monophyletic sister group to S. kalvikus. Hence, they were considered to represent a novel species, which was named Sarcocystis lutrae. Sequence comparisons and phylogenetic analyses based on sequences of the 18S and 28S rRNA genes and cox1, for which little or no sequence data were available for S. kalvikus, revealed that S. lutrae otherwise was most closely related to various Sarcocystis spp. using birds or carnivores as intermediate hosts. The cox1 sequences of S. lutrae from the otters were identical to two sequences from an arctic fox, which in a previous study had been assigned to Sarcocystis arctica due to a high identity (99.4 %) with the latter species at this gene and a complete identity with S. arctica at three other loci when using the same DNA samples as templates for PCR reactions. Additional PCR amplifications and sequencing of cox1 (ten sequences) and the ITS1 region (four sequences) using four DNA samples from this fox as templates again generated cox1 sequences exclusively of S. lutrae, but ITS1 sequences of S. arctica, and thus confirmed that this arctic fox had acted as intermediate host for both S. arctica and S. lutrae. Based on the phylogenetic placement of S. lutrae, the geographical location of infected animals (otters, arctic fox) and the distribution of carnivores/raptors which may have interacted with them, the white-tailed eagle (Haliaeetus albicilla) seems to be a possible definitive host of S. lutrae. Some of the muscle samples from both otters were shown to harbour stages of Toxoplasma gondii through PCR amplification and sequencing of the entire ITS1 region (five isolates) and/or the partial cytb (eight isolates) and cox1 (one isolate). These sequences were identical to several previous sequences of T. gondii in GenBank. Thus, both otters had a dual infection with S. lutrae and T. gondii.

Acute onset of encephalomyelitis with atypical lesions associated with dual infection of Sarcocystis neurona and Toxoplasma gondii in a dog

A two-year-old male, neutered, basset hound-beagle mix with progressive neurological impairment was examined postmortem. Grossly, the dog had multiple raised masses on the spinal cord between nerve roots. Microscopically, the dog had protozoal myeloencephalitis. Toxoplasma gondii and Sarcocystis neurona were detected in the CNS by immunohistochemistry and polymerase chain reaction (PCR). Sarcocysts in formalin-fixed muscle were negative for Sarcocystis by PCR. Banked serum was negative for T. gondii using the modified agglutination test, suggesting an acute case of T. gondii infection or immunosuppression; however, no predisposing immunosuppressive diseases, including canine distemper, were found. To the authors' knowledge, this is the first report of dual T. gondii and S. neurona infection in a dog.

Muscular sarcocystosis in two arctic foxes (Vulpes lagopus) due to Sarcocystis arctica n. sp.: sarcocyst morphology, molecular characteristics and phylogeny

The arctic fox (Vulpes lagopus) is a critically endangered species in Norway, and therefore, the small population is closely monitored, and most foxes found dead are subjected to necropsy. In two deceased foxes, thin-walled muscular sarcocysts were first detected in histological sections, and numerous sarcocysts were later found in frozen and thawed muscle samples from Fox 1. These sarcocysts measured 1-12 × 0.1-0.25 mm and had closely spaced, short, knob-like protrusions, giving the cysts a serrated outline. Genomic DNA was extracted from eight isolated sarcocysts (Fox 1) and two muscle samples (Fox 2) and subjected to polymerase chain reaction amplification at four loci: the nuclear 18S and 28S ribosomal RNA genes and internal transcribed spacer 1 region and the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Both foxes were infected by the same Sarcocystis sp., which displayed little or no genetic variation at the three nuclear loci (99.9-100% identity) and slightly more variation at cox1 (99.4-100% identity). Sequence comparisons and phylogenetic analyses revealed that this species was distinct from other named Sarcocystis spp. but was closely related to various species using avian intermediate hosts and possibly identical to an unnamed species reported from two American dogs. The species described from the two arctic foxes was named Sarcocystis arctica n. sp.