Wild and domestic animals as hosts of Toxoplasma gondii in Finland

Toxoplasma gondii is a widespread protozoan parasite of humans, domestic animals, and wildlife. In this work including nationwide epidemiological cross-sectional studies and descriptive case series studies, T. gondii was confirmed as endemic, common, and sometimes fatal in a selection of animal hosts in Finland. Antibodies against T. gondii were detected in all host species investigated, including hosts hunted or raised for human consumption. The samples were screened with a commercial direct agglutination test using a conservative cut-off for seropositivity. Specific anti-T. gondii IgG antibodies were detected in 9.6% of the 1215 moose (Alces alces), 26.7% of the 135 white-tailed deer (Odocoileus virginianus), and 17.6% of the 17 roe deer (Capreolus capreolus) examined. Seropositive animals were found in 76.3% of 97 sheep farms and 60.0% of 25 wild boar farms, while antibodies were detected in 24.6% of the 1940 individual sheep (Ovis aries) and 33.0% of the 197 farmed wild boars (Sus scrofa) examined. Both of the possible definitive hosts present in Finland had commonly encountered the parasite: 48.4% of the 490 domestic cats (Felis catus) and 86.1%, a significantly higher proportion, of the 337 Eurasian lynx (Lynx lynx) tested seropositive. Raw meat in the diet was a major risk factor (odds ratio 2.0) for the infection in domestic cats. Evidence of exposure to T. gondii followed a north-south gradient in several hosts. The prevalence data indicate an environment contaminated with oocysts. PCR-confirmed T. gondii oocysts were found in one (0.8%) of the fecal samples from domestic cats. None of the lynx shed oocysts. Cats also died of toxoplasmosis; the proportional mortality rate was 3.1% among the 193 domestic cats examined postmortem. The first local T. gondii isolates (FIN1 and FIN2) were obtained from two cats into cell culture. Toxoplasma gondii also caused deaths in species considered highly susceptible to clinical toxoplasmosis. The proportional mortality rates were 8.1% in 173 European brown hares (Lepus europaeus), 2.7% in 148 mountain hares (L. timidus), and 15.8% in a limited number of 19 Eurasian red squirrels (Sciurus vulgaris). Direct genotyping of T. gondii strains was based on analysis of length polymorphism at six microsatellite markers (B18, TUB2, TgM-A, W35, B17, and M33); one fingerprinting marker (M48) was included for further characterization. Both wild and domestic animals were infected with strains belonging to genotype II, which was also the genotype of the oocysts shed. Strains of genotype II had caused all 27 fatal cases investigated in detail. The observed fatality rates among apparently immunocompetent animals challenge the prevailing assumption of nonvirulence of genotype II strains. Toxoplasma gondii infections represent both a public health issue and a welfare issue for its hosts. The parasite thrives in Finland and should not be underestimated.Toksoplasma (Toxoplasma gondii) on maailmanlaajuisesti esiintyvä ihmisiin ja muihin tasalämpöisiin eläimiin tarttuva alkueläinloinen. Eläimet kohtaavat toksoplasmaloisen Suomessa usein. Valtaosa tartunnoista on lieväoireisia, mutta toksoplasmoosi voi pahimmillaan johtaa kuolemaan. Noin joka kymmenes väitöskirjatutkimuksessa tutkituista 1215 hirvestä, joka neljäs 1940 lampaasta ja 152 kauriista, joka kolmas 197 tarhatusta villisiasta, joka toinen 490 kissasta sekä valtaosa 337 ilveksestä oli altistunut toksoplasmatartunnalle ja muodostanut vasta-aineita. Vasta-aineet todettiin suoralla agglutinaatiomenetelmällä. Toksoplasmaloisen kohdanneita yksilöitä todettiin kaikissa tutkituissa eläinlajeissa ja niiden joukossa oli yhteensä satoja elintarvikkeeksi kasvatettuja ja metsästettyjä eläimiä. Tartunta oli yleisempi maan etelä- ja lounaisosissa sekä vanhemmissa eläimissä. Lihansyöjät saavat toksoplasmatartunnan usein syömällä toksoplasmatartuntaa kantavan eläimen lihaa riittämättömästi kypsennettynä. Raa’an lihan syönti oli hyvin yleistä lemmikkikissoilla ja varmistui niillä riskitekijäksi vasta-ainepositiivisuudelle. Kasvinsyöjäeläinten vasta-ainetulokset viittaavat siihen, että niiden ympäristössä on toksoplasmaloisen ympäristömuotoja, ookystia, koska kasvinsyöjien hankitut tartunnat ovat tyypillisesti peräisin niistä. Kissaeläimet voivat erittää ookystia ulosteissaan tartunnan saatuaan. Yhden kissan ulostenäytteissä todettiin mikroskopoimalla ookystia, jotka varmistuivat toksoplasman ookystiksi DNA-monistuksella. Vasta-aineita muodostaneilla kissoilla on oletetusti aiemmin ollut ookystien eritysjakso. Toksoplasmakantojen perimän tutkimukset osoittivat, että samaan perimätyyppiin kuuluvat kannat aiheuttivat tartuntoja sekä riistaeläimissä että kotieläimissä. Loisen perimän mikrosatelliittialueiden toistojaksojen lukumäärän monimuotoisuutta hyödyntävä tyypitysmenetelmä päivitettiin kattamaan kuusi merkkialuetta ja yksi sormenjälkitason profilointialue. Tutkimusaineistona oli tuoreiden tapausten lisäksi uutena sovelluksena arkistoituja kudosnäytteitä. Loisen perimätyypin II kantoja on pidetty lähinnä lieväoireista tai oireetonta toksoplasmoosia aiheuttavina. Tutkimuksessa niiden osoitettiin kuitenkin aiheuttaneen neljäntoista rusakon, neljän metsäjäniksen, kolmen oravan ja kuuden kissan kuoleman. Immunohistokemiallisella erikoisvärjäyksellä loisia havaittiin suurina määrinä niiden useissa elimissä; ilman erikoisvärjäystä loisten lukumäärä ja leviäminen olisi aliarvioitu. Kaksi loiskannoista eristettiin kasvamaan soluviljelmissä. Kuolemaan johtaneet toksoplasmatartunnat vaikuttivat edenneen nopeasti yleistyneeksi sairaustilaksi, vaikka kuolleilla ei todettu altistavia muita sairauksia tai puolustuskyvyn heikkoutta. Toksoplasmaloistartunta oli vasta-ainetutkimuksen perusteella suomalaiskissoissa yhtä yleinen kuin 90-luvulla, ja tartunta voi olla kissallekin hengenvaarallinen. Kolme kissaa sadasta kuolinsyyn selvitykseen lähetetystä oli kuollut yleistyneeseen toksoplasmoosiin. Lisäksi kotikissa on kiistatta Suomessa esiintyvistä loisen isäntäeläimistä merkittävin loisen ympäristömuotojen tuottaja ja siksi tehokkaasti loista monistava ja levittävä isäntä, jonka toksoplasmaloistartunta voi aiheuttaa suoraan tai välillisesti tartuntariskin muille eläimille ja ihmisille. Eläimistä etenkin lemmikkikissoja olisi siis syytä suojella toksoplasmatartunnoilta tehokkaammin

Seroprevalence of Toxoplasma gondii in free-ranging wild boars hunted for human consumption in Estonia

Background: Although the prevalence of human Toxoplasma gondii infections is high in Estonia, no information is available on the prevalence of infections in the local animal populations. Wild boars are a good indicator species for estimating the prevalence and spread of T. gondii and were thus investigated in this nationwide cross-sectional study. Volunteer hunters sampled cardiac or skeletal muscle of 471 wild boars legally hunted for human consumption in Estonia during the hunting season of 2012-2013. Serosanguineous meat juice samples were obtained from thawed tissue samples, diluted 1: 40, and screened for specific anti-T. gondii IgG antibodies with a commercial direct agglutination test. Results: Almost one-quarter (113; 24%) of the wild boars examined were seropositive for T. gondii. The seroprevalence did not differ significantly between age groups or sexes. The seroprevalence was lowest in Viljandimaa, which is located in the southern part of Estonia. In other counties, the infection was evenly prevalent. Conclusions: In Estonia, wild boars are commonly exposed to T. gondii, which is endemic and widespread. The consumption of raw or undercooked meat of Estonian wild boars may pose an infection risk to humans and other hosts.Peer reviewe

Is transport distance correlated with animal welfare and carcass quality of reindeer (Rangifer tarandus tarandus)?

Background: Slaughter reindeer are exposed to stress caused by gathering, handling, loading and unloading, and by conditions in vehicles during transport. These stress factors can lead to compromised welfare and trauma such as bruises or fractures, aspiration of rumen content, and abnormal odour in carcasses, and causing condemnations in meat inspection and lower meat quality. We investigated the statistical association of slaughter transport distance with these indices using meat inspection data from years 2004-2016, including inspection of 669,738 reindeer originating from Finnish reindeer herding areas. Results: Increased stress and decreased welfare of reindeer, as indicated by higher incidence of carcass condemnation due to bruises or fractures, aspiration of rumen content, or abnormal odour, were positively associated with systems involving shorter transport distances to abattoirs. Significant differences in incidence of condemnations were also detected between abattoirs and reindeer herding cooperatives. Conclusions: This study indicates that in particular the short-distance transports of reindeer merit more attention. While the results suggest that factors associated with long distance transport, such as driver education, truck design, veterinary supervision, and specialist equipment, may be favourable to reducing pre-slaughter stress in reindeer when compared with short distance transport systems, which occur in a variety of vehicle types and may be done by untrained handlers. Further work is required to elucidate the causal factors to the current results.Peer reviewe

High Toxocara cati prevalence in wild, free-ranging Eurasian lynx (Lynx lynx) in Finland, 1999-2015

In Finland, free-ranging Eurasian lynx (Lynx lynx) population has grown from 30 to 40 individuals to 2800 individuals since the species became partly protected in 1962. Changes in host population size are known to have an impact on host-parasite dynamics, and the Eurasian lynx population in Finland provides a unique opportunity for studying the potential effects of dramatic population increase and expansion of a solitary apex predator on their parasite prevalence and abundance. Toxocara cati is a zoonotic gastrointestinal parasite infecting domestic cats and wild felids worldwide. We studied T. cati infection prevalence and worm burden in 2756 Eurasian lynx individuals from Finland, covering the years 1999-2015. Toxocara cati worms that had been collected from intestinal contents were identified based on morphology. We performed regression analyses to investigate possible associations of age, sex, and host population density with T. cati infection. We found T. cati from 2324 (84.3%, 95% confidence interval 82.9-86.0) of the examined lynx. Each year, the infection prevalence was higher than 75% and not density dependent. The parasites were strongly aggregated, with older individuals harboring fewer T. cati than younger ones did. Old females aged 9-15 years had higher T. cati abundance than males of the same age group. Our results indicate that T. cati was a common and abundant parasite of Eurasian lynx throughout the study period, regardless of the changing population size and density.Peer reviewe

Gastrointestinal parasites in reindeer (Rangifer tarandus tarandus) calves from Fennoscandia : An epidemiological study

Reindeer (Rangifer tarandus tarandus) host numerous parasites. Although there is a general knowledge about parasite diversity in reindeer, detailed baseline information about parasitic infections is limited. Detailed knowledge of parasite prevalence and diversity provide a pathway for more targeted parasite control, an increasing need expected in the future. The main aim of our cross-sectional study was to estimate the prevalence of gastrointestinal parasites in semidomesticated reindeer calves. The 480 reindeer calves included in our study were aged 6–7 months, originated from 9 reindeer herding cooperatives in Finland and 1 in Norway, and were slaughtered during September–November 2015 in 10 reindeer slaughterhouses. All the reindeer calves passed meat inspection, and the detected parasitic infections were subclinical. As the reindeer included in this study were young animals intended for slaughter, they had never been administrated any antiparasitic treatment. Assessments of gastrointestinal parasitism among these reindeer calves were based on fecal examination and morphological identification of coccidian oocysts or helminth eggs. Individual fecal samples collected from the rectum of each of the reindeer were examined using a modified McMaster method. Most (78.3%) of the reindeer calves had eggs or oocysts of at least one parasite species in their feces, and more than half (53.5%) had a mixed infection. Strongylid eggs were detected in 75.6%, Eimeria sp. oocysts in 50.6%, Moniezia sp. eggs in 28.1%, Nematodirus sp. eggs in 22.1%, Capillaria sp. eggs in 9.4%, and Trichuris sp. eggs in 0.6% of the samples. The prevalence of gastrointestinal parasites was similar or higher relative to previous estimates from the region; the proportion of reindeer calves shedding strongylid eggs and the proportion of reindeer calves shedding Moniezia sp. eggs had increased. Prevalence varied by geographical region, which may reflect different herding practices or environmental parameters. Higher reindeer density was a risk factor for testing positive for Eimeria sp. oocysts, and the odds of testing positive for Nematodirus sp. eggs were higher if a peroral route was used for antiparasitic treatment in the reindeer herding cooperative. The mean proportion of reindeer estimated to receive antiparasitic treatment in Finland was 86% in 2004–2005 and 91% in 2014–2015. During the historical time frames of current management practices, this routine annual antiparasitic treatment of breeding reindeer has not decreased the prevalence of gastrointestinal parasites in reindeer calves, which can be seen as sentinels or indicators of the infection pressure.Peer reviewe

Trichinella spp. in Wild Boars (Sus scrofa), Brown Bears (Ursus arctos), Eurasian Lynxes (Lynx lynx) and Badgers (Meles meles) in Estonia, 2007-2014

Simple Summary Trichinellosis is an important foodborne zoonosis. In Estonia, Trichinella infections are endemic in wild animals. This paper summarizes findings of Trichinella-parasites during an 8-year period in Estonia in selected host species: wild boars, brown bears, Eurasian lynxes, and badgers. The results highlight that testing wildlife hunted for human consumption for Trichinella is important, and that there is room for improvement in the proportion of hunted animals tested. In this study, we summarize Trichinella findings from four wild, free-ranging host species from Estonia during 2007-2014. Trichinella spp. larvae were detected in 281 (0.9%, 95% confidence interval (CI) 0.8-1.0) of 30,566 wild boars (Sus scrofa), 63 (14.7%, 95% CI 11.6-18.3) of 429 brown bears (Ursus arctos), 59 (65.56%, 95% CI 55.3-74.8) of 90 Eurasian lynxes (Lynx lynx), and three (60.0%, 95% CI 18.2-92.7) of five badgers (Meles meles). All four European Trichinella species were detected: T. britovi in 0.7% of the wild boars, 7.2% of the brown bears, 45.6% of the lynxes, and 40.0% of the badgers; T. nativa in 0.1% of the wild boars, 5.8% of the brown bears, and 20.0% of the lynxes; T. pseudospiralis in 0.02% the wild boars; and T. spiralis in 0.03% of the wild boars and 4.4% of the lynxes. The results include the first description from Estonia of T. britovi in brown bear and badgers, T. pseudospiralis in wild boars, and T. spiralis in wild boars and lynxes. The results indicate high infection pressure in the sylvatic cycles across the years-illustrating continuous risk of spillover to domestic cycles and of transmission to humans.Peer reviewe

Toxoplasma gondii in the Subarctic and Arctic

Volume: 52Non peer reviewe

Gastrointestinal parasites in reindeer (Rangifer tarandus tarandus): A review focusing on Fennoscandia

Reindeer (Rangifer tarandus tarandus) are known to host a wide variety of parasites, including those in the gastrointestinal system. Here, we review the current knowledge of the main gastrointestinal parasites of reindeer focusing on northern Fennoscandia, which comprises parts of Finland, Sweden, Norway and Russia. We explore both the historical baseline data for diversity and distribution and recent advancements in our understanding of parasite faunas in reindeer across this region. It is evident that the balance between reindeer and their gastrointestinal parasites, along with the potential for emergent disease in the changing world warrants careful monitoring and further studies.Peer reviewe

Milloin on hyvä muistaa lemmikkivälitteisen zoonoosin mahdollisuus?

Vertaisarvioitu.Peer reviewe