Exploring the epidemiological role of the Eurasian lynx (Lynx lynx) in the life cycle of Toxoplasma gondii

Toxoplasma gondii from Gabonese forest, Central Africa: First report of an African wild strain

The protozoan Toxoplasma gondii is a ubiquitous and highly prevalent parasite that can theoretically infect all warm-blooded vertebrates. In humans, toxoplasmosis causes infections in both immunodeficient and immunocompetent patients, congenital toxoplasmosis, and ocular lesions. These manifestations have different degrees of severity. Clinical severity is determined by multiple factors, including the genotype of the T. gondii strain involved in the infection. T. gondii exhibits remarkable genetic diversity, which varies according to geography and ecotype (domestic or wild). Previous studies have demonstrated that wild strains of T. gondii are of particular epidemiological interest, as they have been associated with more severe forms of toxoplasmosis in different regions of the world. However, no data on wild strains of T. gondii are available from Africa. In this study, we describe for the first time a wild T. gondii strain from Africa. Wild animals from the forest environment of Gabon, Central Africa, were screened for chronic infection with T. gondii using quantitative PCR. The infecting T. gondii strains were genotyped whenever possible by the analysis of 15 microsatellite markers and by whole-genome sequencing. A new T. gondii genotype was identified in the DNA extract from a heart sample of a duiker (Cephalophus sp.) and was found to be highly divergent from previously described T. gondii populations worldwide, including those from domestic environments in Gabon. This discovery suggests the existence of a wild T. gondii population in Africa. The role of wild T. gondii strains in the incidence of severe toxoplasmosis in Africa remains unclear and requires further investigation.

Fatal Feline Leukemia Virus-Associated Enteritis in a Wild Eurasian Lynx (Lynx lynx) in Germany

The Eurasian lynx (Lynx lynx), a widespread wild felid on the Eurasian continent, is currently classified as "critically endangered" in Germany. Understanding the impact of infectious agents is of particular importance for the continued conservation of these animals, especially regarding pathogens with broad host ranges and risk of interspecies transmission. Feline leukemia virus (FeLV) is known to infect wild and domestic felids worldwide, including several species of lynx, but it has not been reported thus far in the Eurasian lynx. In September 2020, a 16-month-old female Eurasian lynx from the Bavarian Forest, Germany, showed a sudden onset of gastrointestinal signs such as anorexia, diarrhea, and vomiting, and died within one week. Macroscopic and histologic examination revealed hemorrhagic-necrotizing enteritis and typhlocolitis, with the degeneration of crypts and crypt abscesses, as well as depleted Peyer's patches. In addition, the animal showed lymphoid depletion (lymph nodes, thymus, and spleen) and hypocellularity of the bone marrow. FeLV infection was confirmed by immunohistochemistry and next generation sequencing. A secondary bacterial infection with hemolytic Escherichia coli and Clostridium perfringens type A was present in the intestine. This is the first report of FeLV-associated enteritis, lymphoid depletion and bone marrow suppression with associated secondary bacterial infection in a Eurasian lynx.

Seroprevalence of infectious pathogens of zoonotic and veterinary importance in wild ruminants from Slovenia

Introduction

Wildlife represents an increasingly important source of pathogens of medical and veterinary importance. Surveillance in wildlife offers an insight on current epidemiological status of selected pathogens and help to prevent spillovers to humans and livestock.

Material and methods

Our study included 312 wild ruminants belonging to five species: Roe deer (n = 134), red deer (n = 113), Alpine chamois (n = 53), European mouflon (n = 10) and Alpine ibex (n = 2). Seven pathogens that may have profound effect on human/livestock health and economic viability of the farms were tested using serological methods.

Results

Antibodies against Toxoplasma gondii, Neospora caninum, Coxiella burnetii, Brucella spp., Chlamydophila abortus, Mycobacterium avium subsp. paratuberculosis (MAP) and Mycobacterium bovis were detected in 34.62% (108/312), 0.96% (3/312), 2.24% (7/312), 0, 0.96% (3/312), 0, 0.64% (2/312) of animals tested, respectively. Because of low prevalences, risk factors were assessed only for T. gondii. Sex (female>male) and species (roe deer>red deer, roe deer>Alpine chamois) were significantly associated with the T. gondii positive outcome, while age was not.

Discussion

Adult males had the lowest T. gondii prevalence which offers future research opportunities. The lower seroprevalence of most investigated pathogens suggests game meat, if properly cooked, as being relatively safe for human consumption. This is the first study investigating the seroprevalence and associated risk factors of selected pathogens in wild ruminants in Slovenia.

Revealing the Prevalence of Toxoplasma in Sierra Morena's Wild Boar: An ELISA-Based Study Using Meat Juice

This research work focused on the prevalence of Toxoplasma gondii in wild boar from the Sierra Morena region. We conducted an ELISA analysis using meat juice samples. A total of 892 samples from six hunting seasons (2013-2019) were collected from the provinces that constitute the Sierra Morena Mountain range. These samples were analyzed using the Pigtype® ELISA kit, specifically developed for detecting T. gondii in meat juice. The overall prevalence of T. gondii in Sierra Morena was 23.2%. The highest prevalences were observed in Córdoba (31.6%) and Jaén (25.9%). These provinces exhibit the highest density of wild boar as well as the greatest presence of the Iberian lynx (Lynx pardinus). Further in-depth studies are necessary, but it appears that the presence of wild felids and scavenger behavior may be associated with this observation.

Drivers of infection with Toxoplasma gondii genotype type II in Eurasian red squirrels (Sciurus vulgaris)

BACKGROUND

In September 2014, there was sudden upsurge in the number of Eurasian red squirrels (Sciurus vulgaris) found dead in the Netherlands. High infection levels with the parasite Toxoplasma gondii were demonstrated, but it was unclear what had caused this increase in cases of fatal toxoplasmosis. In the present study, we aimed to gain more knowledge on the pathology and prevalence of T. gondii infections in Eurasian red squirrels in the Netherlands, on the T. gondii genotypes present, and on the determinants of the spatiotemporal variability in these T. gondii infections. The presence of the closely related parasite Hammondia hammondi was also determined.

METHODS

Eurasian red squirrels that were found dead in the wild or that had died in wildlife rescue centres in the Netherlands over a period of seven years (2014-2020) were examined. Quantitative real-time polymerase chain reaction was conducted to analyse tissue samples for the presence of T. gondii and H. hammondi DNA. Toxoplasma gondii-positive samples were subjected to microsatellite typing and cluster analysis. A mixed logistic regression was used to identify climatic and other environmental predictors of T. gondii infection in the squirrels.

RESULTS

A total of 178 squirrels were examined (49/178 T. gondii positive, 5/178 H. hammondi positive). Inflammation of multiple organs was the cause of death in 29 squirrels, of which 24 were also T. gondii polymerase chain reaction positive. Toxoplasma gondii infection was positively associated with pneumonia and hepatitis. Microsatellite typing revealed only T. gondii type II alleles. Toxoplasma gondii infection rates showed a positive correlation with the number of days of heavy rainfall in the previous 12 months. Conversely, they showed a negative association with the number of hot days within the 2-week period preceding the sampling date, as well as with the percentage of deciduous forest cover at the sampling site.

CONCLUSIONS

Toxoplasma gondii infection in the squirrels appeared to pose a significant risk of acute mortality. The T. gondii genotype detected in this study is commonly found across Europe. The reasons for the unusually high infection rates and severe symptoms of these squirrels from the Netherlands remain unclear. The prevalence of T. gondii in the deceased squirrels was linked to specific environmental factors. However, whether the increase in the number of dead squirrels indicated a higher environmental contamination with T. gondii oocysts has yet to be established.

Toxoplasma gondii Infection in the Eurasian Beaver (Castor fiber) in Switzerland: Seroprevalence, Genetic Characterization, and Clinicopathologic Relevance

Toxoplasma gondii is a coccidian parasite able to infect all warm-blooded animals and humans. Rodents are one of the most important intermediate hosts for T. gondii, but little is known about infection in beavers and its clinical relevance. Toxoplasmosis was not considered an important waterborne disease until recently, but with increased outbreaks in humans and animals this perspective has changed. Serum samples from 247 Eurasian beavers (Castor fiber) collected from 2002 to 2022 were tested for antibodies to T. gondii by a commercial ELISA. Antibodies to T. gondii were found in 113 (45.8%) beavers. Higher weight and proximity to urban areas were found to be significant predictors for seropositivity. Additionally, T. gondii DNA was detected in 23/41 brain tissue samples by real-time PCR. Histopathologic examination of brain sections revealed inflammatory changes in 26/40 beavers, mainly characterized by encephalitis, meningitis, choroid plexitis, or a combination of them. In six of these cases the lesions were in direct association with parasitic stages. With an adapted nested PCR multilocus sequence typing and in silico restriction fragment length polymorphism analysis approach, three different T. gondii genotypes were detected in brain samples: the clonal Type II strain (ToxoDB 1), a Type II variant (ToxoDB 3), and a novel genotype exhibiting both Type II and I alleles in a further animal. Toxoplasma gondii infections in beavers have epidemiologic and clinical significance. The high seroprevalence indicates frequent contact with the parasite, and as competent intermediate hosts they may play an important role, contributing to maintaining the life cycle of T. gondii in semiaquatic habitats. In addition, although most beavers appear to develop subclinical to chronic disease courses, acute and fatal outcomes, mainly characterized by encephalitis and generalized infection, do also occur.

Toxoplasma gondii seroprevalence in reindeer (Rangifer tarandus tarandus L.) in northern Sweden: a cross-sectional study from 2014

BACKGROUND

Toxoplasma gondii is a parasitic protozoan that can infect a wide range of warm-blooded animals, including humans. The infection with T. gondii, is of particular concern due to its potential impact on human and animal health. In Sweden, semi-domesticated reindeer (Rangifer tarandus tarandus L.) is an important species both economically and culturally, but susceptibility to Toxoplasma infection and seroprevalence in reindeer herds remain relatively understudied.

RESULTS

A total of 528 reindeer, sampled at two slaughterhouses in Sweden in 2014, were investigated for antibodies to T. gondii. Specific antibodies to T. gondii were found in 5 of 209 (2.3%) tested adult reindeer and in 6 of 308 (1.9%) tested calves, giving an apparent total prevalence of 2.1% (95% confidence interval 1.1-3.8%). None of four putative risk factors studied (sex, age, type of grazing area, county) were statistically associated with T. gondii seroprevalence.

CONCLUSIONS

Swedish semi-domesticated reindeer are exposed to T. gondii and may harbour infectious tissue cysts. To mitigate the risk of T. gondii infection in consumers, reindeer meat should be frozen or cooked thoroughly before consumption. The global climate change may influence the seroprevalence and possible associated risk factors for T. gondii in reindeer. To be able to manage the risk and get better advice to the consumers there is a need for further investigations covering the whole spectra of herding conditions for reindeer.

Prevalence of Toxoplasma gondii in Endangered Wild Felines (Felis silvestris and Lynx pardinus) in Spain

The wildcat (Felis silvestris) and the Iberian lynx (Lynx pardinus) are important species in Spain, considered as near-threatened and endangered, respectively. Both can be infected by Toxoplasma gondii, a parasite that can cause morbidity and mortality in transplacentally-infected or immunocompromised mammals. The data on the prevalence of this parasite in wild populations of these species in Spain are outdated. The objective of this study was to update information and evaluate the role of these felines in parasite epidemiology and the potential impact of the parasite on their conservation. Blood and fecal samples were collected from captured animals, as well as the tongue, diaphragm, and spleen, from animals killed in road accidents in central Spain. An indirect fluorescent antibody test (IFAT) was used to detect parasite antibodies in serum, microscopy and molecular analysis were used to detect oocysts in feces, and molecular analysis was used to determine the existence of tissue cysts. Seroprevalence was 85% in wildcats and 45% in lynx, and parasite DNA was detected in the feces of one wildcat and in tissue samples from 10 wildcats and 11 Iberian lynxes. These results highlight the epidemiological importance and high risk of T. gondii infection in animals and humans in the studied areas. Considering feline susceptibility to infection, monitoring programs are needed to assess the health status of wild felines.