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A cross-sectional study of Trichinella spp. infection in wolves (Canis lupus) reveals first evidence of T. spiralis in the species in Poland Cover

A cross-sectional study of Trichinella spp. infection in wolves (Canis lupus) reveals first evidence of T. spiralis in the species in Poland

Journal of Veterinary Research
Volume 69 (2025): Issue 3 (September 2025)
By:
Open Access
|Sep 2025

Figures & Tables

Fig. 1.

Boxplots for the number of Trichinella spp. larvae per gram (lpg) of three types different muscle tissues from 43 infected grey wolves. The line inside the box is the median. The top and bottom lines of the box are the 25th and 75th quartiles, respectively. The top and bottom whiskers mark the 5th and 95th quartiles, respectively. The dots represent outliers. Statistically significant differences with P-value < 0.05 are marked with asterisks
Boxplots for the number of Trichinella spp. larvae per gram (lpg) of three types different muscle tissues from 43 infected grey wolves. The line inside the box is the median. The top and bottom lines of the box are the 25th and 75th quartiles, respectively. The top and bottom whiskers mark the 5th and 95th quartiles, respectively. The dots represent outliers. Statistically significant differences with P-value < 0.05 are marked with asterisks

Fig. 2.

Boxplots for the number of Trichinella spp. larvae per gram (lpg) of three types different muscle tissues divided into T. britovi and T. spiralis from 23 and 20 infected grey wolves, respectively. The line inside the box is the median. The top and bottom lines of the box are the 25th and 75th quartiles, respectively. The top and bottom whiskers mark the 5th and 95th quartiles, respectively. The dots represent outliers. Statistically significant differences with P < 0.05 are marked with asterisks
Boxplots for the number of Trichinella spp. larvae per gram (lpg) of three types different muscle tissues divided into T. britovi and T. spiralis from 23 and 20 infected grey wolves, respectively. The line inside the box is the median. The top and bottom lines of the box are the 25th and 75th quartiles, respectively. The top and bottom whiskers mark the 5th and 95th quartiles, respectively. The dots represent outliers. Statistically significant differences with P < 0.05 are marked with asterisks

Fig. 3.

Distribution of wolves included in the study. Red dot – T. spiralis-positive grey wolf; green dot – T. britovi-positive grey wolf; yellow square – Trichinella-negative grey wolf
Distribution of wolves included in the study. Red dot – T. spiralis-positive grey wolf; green dot – T. britovi-positive grey wolf; yellow square – Trichinella-negative grey wolf

Fig. 4.

Boxplots for the number of Trichinella spp. larvae per gram (lpg) of three types different muscle tissues in relation to the age of wolves. The line inside the box is the median. The top and bottom lines of the box are the 25th and 75th quartiles, respectively. The top and bottom whiskers mark 5th and 95th quartiles, respectively. The dots represent data outliers. No statistically significant differences with P-value < 0.05 were found
Boxplots for the number of Trichinella spp. larvae per gram (lpg) of three types different muscle tissues in relation to the age of wolves. The line inside the box is the median. The top and bottom lines of the box are the 25th and 75th quartiles, respectively. The top and bottom whiskers mark 5th and 95th quartiles, respectively. The dots represent data outliers. No statistically significant differences with P-value < 0.05 were found

Summary of Trichinella spp_ prevalence reports in wolves in North America, Asia and Europe by country, period, parasite species assigned and sample type

Country (region)Source (Reference)Sampling periodSample sizeTrichinella spp. prevalence (%)Trichinella speciesaTissueb
Finland(1)1995–200510239.2Tn (Tb, Ts)m/d/fl
Finland(53)2011–20138534.1Tn (Tb, Ts)no data
Finland(52)1996–19981833.0Tn, Tbno data
Sweden(40)2014–20191975.6Tn, Tbno data
Latvia(22)2010–201423100.0Tbfl
Latvia(6)2003–2008no data69.0no datano data
Latvia(7)2010–2012869.7no datam
Estonia(29)1992–19993479.4Tn, Tbm
Romania (Carpathians)(16)2000–20053531.0Tbm
Romania (Central)(25)199139930.5Tbno data
Romania (Transylvania)(25)1999–2002771.4Tbno data
Romania (Transylvania)(25)2014–2015366.7Tbno data
USA and Canada(37)2001–201324451.0T6, Tntg
Canada (North) and USA(54)2022no data13–52T6, Tnno data
Greenland(54)no datano data50.0T6, Tnno data
Estonia(54)1992–1996no data75–79T6, Tnno data
Estonia(54)1999no data63.20T6, Tnno data
Finland, Norway, Russia (Kola Peninsula), Sweden(54)no datano data32–39T6, Tnno data
Russia(54)no datano data10–65T6, Tnno data
Russia(60)1998–20008297.50Tn, Tbfl
Russia(20)1998–20007597.30Tn, Tbcfl
Serbia(81)2009–201011646.50Tb, Tsm
Serbia, Bosnia and Herzegovina, Macedonia(74)2006–201311646.5Tbtg
Serbia(74)2011–2022 49.50Tbno data
Bosnia and Herzegovina(55)2013–20233638.89Tbm
Canada (Alberta)(27)1975–19772175.50no datatg, m, d
Canada (North)(38)2001–20158162.00no datam, tg
Kazakhstan(75)2020–20238320.50Tnm, d
Kazakhstan(2)2013–20239820.40no datam
Poland(51)1999–20071040.0Tbno data
Poland(10)1999–20152154.50Tbm, d, fl
Poland (Carpathians)(18)1996–2004650.00Tbno data
Italy(24)2008–2012678.9Tbm
Italy(4)2004–201421827.1Tbm
Italy(71)1987–19934819.0Tbd
Italy(69)1991–19932528.0Tbd, fl
Italy(61)1985–19958131.0Tbm
Italy(3)2015–202021328.0Tbd, fl
Italy (Western Alps)(43)2017–202213011.53Tbd
Slovakia (Tatras)(28)2005–200640no datad, fl
Spain(67)1996–19994712.8Tbm
Croatia(8)1996–20076731.0Tb, Tsm
Germany(39)2007–2014533.70Tb, Tsd
Germany(30)2013–20235454.04Tb, Tsd

Sensitivities of the detection two species of Trichinella and the larvae burden (number larvae per gram - lpg) in three muscle tissues collected from 43 infected grey wolves

Type of muscleTrichinella britovi casesTrichinella spiralis cases
n/N (%)aMean number of larvae per g (95% CIb)χ2 (P)cn/N (%)Mean number of larvae per g (95% CI)χ2 (P)c
Forelimb21/23 (91.3)0.48 (0.24–0.86) 19/20 (95.0)0.42 (0.18–0.83)
Diaphragm19/23 (82.6)0.26 (0.1–0.57)4.9 (0.08)15/20 (75.0)0.2 (0.05–0.51)8.3 (0.02)
Tongue13/17d (76.5)0.53 (0.24–1.0) 12/16e (75.0)0.71 (0.36–1.23)

Descriptive statistics of Trichinella prevalence among grey wolves in the study

VariableTrichinella spp. prevalenceT. britovi prevalenceT. spiralis prevalence
n/Na% (95% CI)bχ2 (P)cn/Na% (95% CI)b,dχ2 (P)cn/Na% (95% CI)b,dχ2 (P-value)c
Origin (province) 30.6 (0.002) 23.9 (0.02) 31.7 (0.002)
Lubelskie0/30 (0–70.8) 0/3- 0/3-
Lubuskie2/2100 (15.8–100) 1/250 (1.2–98.7) 1/250 (1.2–98.7)
Łódzkie0/20 (0–84.2) 0/1- 0/1-
Małopolskie1/250.0 (12.6–98.7) 1/250 (1.2–98.7) 0/2-
Mazowieckie0/10 (0–97.5) 0/1- 0/1-
Podkarpackie4/580.0 (28.3–99.5) 4/580.0 (28.3–99.5) 0/5-
Podlaskie8/1747.0 (23.0–72.2) 9/1747.0 (23.0–72.2) 0/17-
Pomorskie13/2162.0 (38.4–81.9) 4/2114.3 (3.0–36.3) 9/2147.6 (25.7–70.2)
Śląskie1/425.0 (0.6–80.6) 1/425.0 (0.6–80.6) 0/4-
Świętokrzyskie2/825.0 (3.2–65.1) 1/812.5 (0.3–52.6) 1/812.5 (0.3–52.6)
Warmińsko-mazurskie1/250.0 (1.2–98.7) 1/250 (1.2–98.7) 0/2-
Wielkopolskie0/140 (0.0–23.2) 0/14- 0/14-
Zachodnio-pomorskie11/1573.3 (44.9–92.2) 2/1513.3 (4.3–48.0) 8/1553.3 (26.6–78.7)
Sex 1.9 (0.2) 0.01 (0.9) 0.2 (0.7)
Female20/4643.5 (29.9–58.9) 11/4623.9 (12.6–38.8) 9/4619.6 (9.3–33.9)
Male23/4847.9 (33.3–62.8) 12/4825.0 (13.6–39.6) 11/4822.9 (12.0–37.3)
Age group 4.5 (0.2) 1.8 (0.6) 4.7 (0.2)
Pups1/520.0 (0.5–71.6) 0/50 (0.0-52.2) 1/520.0 (0.5-71.6)
Yearlings4/1040.0 (12.1–73.8) 3/1030.0 (6.7–65.2) 1/1010.0 (0.2–44.5)
Younger adults19/4641.3 (27.0–56.8) 10/4621.7 (10.9–36.4) 9/4619.6 (9.3–33.9)
Older adults6/875.0 (34.9–96.8) 2/825.0 (3.2–65.1) 4/850.0 (15.7–84.3)
Body mass class 1.9 (0.4) 0.9 (0.8) 1.6 (0.4)
Lower (14–25 kg)7/2231.8 (13.8–54.9) 5/2222.7 (7.8–45.4) 2/229.1 (1.1–29.2)
Medium (26–41 kg)19/4344.2 (29.1–60.1) 10/4323.2 (11.8–38.6) 9/4320.9 (10.0–36.0)
Higher (42–57 kg)10/1952.6 (28.9–75.5) 6/1931.6 (12.6–56.6) 4/1921.0 (6.0–45.6)
DOI: https://doi.org/10.2478/jvetres-2025-0046 | Journal eISSN: 2450-8608
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Language: English
Page range: 457 - 468
Submitted on: Feb 7, 2025
Accepted on: Sep 2, 2025
Published on: Sep 17, 2025
Published by: National Veterinary Research Institute in Pulawy
In partnership with: Paradigm Publishing Services
Publication frequency: 4 times per year
Keywords:
wolf,
reservoir,
Poland
Related subjects:
Life sciences,
Molecular biology,
Microbiology and virology,
Life sciences, other,
Medicine,
Veterinary medicine

© 2025 Agnieszka Świątalska, Ewa Bilska-Zając, Weronika Korpysa-Dzirba, Aneta Bełcik, Michał Konrad Krzysiak, Magdalena Larska, published by National Veterinary Research Institute in Pulawy
This work is licensed under the Creative Commons Attribution 4.0 License.

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