Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide







  • Last modified
  • 20 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Animal Disease
  • Preferred Scientific Name
  • Trichinella
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Nematoda
  •       Class: Adenophorea
  •         Subclass: Enoplia

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Trichinella sp. larva in striated muscle.
TitleTrichinella larva
CaptionTrichinella sp. larva in striated muscle.
Copyright©John W. McGarry
Trichinella sp. larva in striated muscle.
Trichinella larvaTrichinella sp. larva in striated muscle.©John W. McGarry


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Preferred Scientific Name

  • Trichinella

International Common Names

  • English: trichinae

Parasitoses name

  • trichinellosis

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Nematoda
  •             Class: Adenophorea
  •                 Subclass: Enoplia
  •                     Order: Enoplida
  •                         Suborder: Trichinellina
  •                             Family: Trichinellidae
  •                                 Genus: Trichinella


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The geographical distributions of the Trichinella species/genotypes have recently been described by Pozio (2000). All species/genotypes seem to have individual ecological niches for which they are adapted (Kapel, 2000). Thus, T. spiralis is found primarily in the domestic habitat in which environmental stress is limited and the high reproductive capacity has a selective advantage. For the sylvatic species/genotypes, tolerance to high and low temperatures and decomposition of host tissue might be more important than the reproductive capacity (Kapel, 2000).

Trichinella spiralis: Temperate regions in Europe, Asia, New Zealand, North and South America.

Trichinella nativa: Arctic and subarctic areas of the Holarctic region. The isotherm –5°C in January appears to be the southern limit of its geographical distribution (see Pozio et al., 1996, 1998).

Trichinella britovi: Temperate areas of the Palearctic region (Europe, Asia). The January isotherm –6°C appears to be the northern limit of its distribution (see Pozio et al., 1996, 1998).

Trichinella nelsoni: Africa south of Sahara.

Trichinella murrelli: Temperate areas of North America.

Trichinella pseudospiralis: This species has been sporadically detected in Europe, Asia, North America, and in the Australian region, however, due to the lack of muscle capsules, the larvae are very difficult to detect by trichinoscopy and this may, in part, explain the low numbers of records.

Trichinella papuae: This species has been recovered very recently in Papua New Guinea and the geographical distribution has yet to be determined.

Trichinella T6: Temperate regions of North America, but too little data are available for defining the exact distribution.

Trichinella T8: T8 has only been detected in South Africa and Namibia, and the geographical distribution has yet to be determined.

Trichinella T9: T9 has only been detected in Japan, and the geographical distribution has yet to be determined.

For selected references to geographical distributions, see Pozio (2000) and Murrell et al. (2000).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 04 Jan 2022
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes


Cabo VerdeAbsent, No presence record(s)Jul-Dec-2019
Central African RepublicAbsentJul-Dec-2019
Congo, Democratic Republic of theAbsent, No presence record(s)
Congo, Republic of theAbsentJan-Jun-2019
DjiboutiAbsent, No presence record(s)Jul-Dec-2019
EthiopiaAbsent, No presence record(s)Jul-Dec-2018
GuineaAbsent, No presence record(s)
LesothoAbsent, No presence record(s)Jan-Jun-2020
MadagascarAbsent, No presence record(s)Jan-Jun-2019
MauritiusAbsent, No presence record(s)Jul-Dec-2019
MayotteAbsent, No presence record(s)Jul-Dec-2019
RéunionAbsent, No presence record(s)Jul-Dec-2019
Saint HelenaAbsent, No presence record(s)Jan-Jun-2019
São Tomé and PríncipeAbsent, No presence record(s)
SeychellesAbsent, No presence record(s)Jul-Dec-2018
Sierra LeoneAbsentJan-Jun-2018
South AfricaAbsentJul-Dec-2019
TogoAbsent, No presence record(s)


BahrainAbsent, No presence record(s)Jul-Dec-2020
BruneiAbsent, No presence record(s)Jul-Dec-2019
ChinaPresent, LocalizedJul-Dec-2018
Hong KongAbsent, No presence record(s)
IndiaAbsent, No presence record(s)Jan-Jun-2019
IranAbsent, No presence record(s)Jan-Jun-2019
IraqAbsent, No presence record(s)Jul-Dec-2019
IsraelPresentJul-Dec-2020; in wild animals only
KuwaitAbsent, No presence record(s)Jan-Jun-2019
LebanonAbsent, No presence record(s)
-Peninsular MalaysiaAbsent, No presence record(s)
-SabahAbsent, No presence record(s)
-SarawakAbsent, No presence record(s)
MaldivesAbsent, No presence record(s)Jan-Jun-2019
North KoreaAbsent, No presence record(s)
PakistanAbsent, No presence record(s)Jan-Jun-2020
PhilippinesAbsent, No presence record(s)
Saudi ArabiaAbsentJan-Jun-2020
SingaporeAbsent, No presence record(s)Jul-Dec-2019
South KoreaAbsentJul-Dec-2019
Sri LankaAbsentJul-Dec-2018
TaiwanAbsent, No presence record(s)Jul-Dec-2019
United Arab EmiratesAbsent, No presence record(s)Jul-Dec-2020


AndorraPresentJul-Dec-2019; in wild animals only
Bosnia and HerzegovinaPresentJul-Dec-2019
CroatiaPresent, LocalizedJul-Dec-2019
CyprusAbsent, No presence record(s)Jul-Dec-2019
CzechiaPresentJul-Dec-2019; in wild animals only
EstoniaPresentJul-Dec-2019; in wild animals only
Faroe IslandsAbsent, No presence record(s)Jul-Dec-2018
FinlandPresentJul-Dec-2019; in wild animals only
FrancePresent, LocalizedJul-Dec-2019
GermanyPresentJul-Dec-2019; in wild animals only
HungaryPresentJul-Dec-2019; in wild animals only
IcelandAbsent, No presence record(s)Jul-Dec-2019
Isle of ManAbsent, No presence record(s)
ItalyPresent, LocalizedJul-Dec-2020; in wild animals only
JerseyAbsent, No presence record(s)
LatviaPresentJul-Dec-2020; in wild animals only
LithuaniaPresentJul-Dec-2019; in wild animals only
LuxembourgAbsent, No presence record(s)
MaltaAbsent, No presence record(s)Jan-Jun-2019
MontenegroPresentJul-Dec-2019; in wild animals only
NetherlandsPresentJul-Dec-2019; in wild animals only
North MacedoniaPresentJul-Dec-2019; in wild animals only
RomaniaPresent, LocalizedJul-Dec-2018
RussiaPresent, LocalizedJan-Jun-2020
San MarinoAbsent, No presence record(s)Jan-Jun-2019
Serbia and MontenegroPresent
SlovakiaPresentJul-Dec-2020; in wild animals only
SpainPresent, LocalizedJul-Dec-2020
SwedenPresentJul-Dec-2020; in wild animals only
SwitzerlandPresentJul-Dec-2020; in wild animals only
United KingdomAbsentJul-Dec-2019

North America

BahamasAbsent, No presence record(s)Jul-Dec-2018
BarbadosAbsent, No presence record(s)Jul-Dec-2020
BermudaAbsent, No presence record(s)
British Virgin IslandsAbsent, No presence record(s)
CanadaPresentJul-Dec-2019; in wild animals only
Cayman IslandsAbsentJan-Jun-2019
CubaAbsent, No presence record(s)Jan-Jun-2019
CuraçaoAbsent, No presence record(s)Jan-Jun-2019
DominicaAbsent, No presence record(s)
Dominican RepublicPresentJan-Jun-2019
El SalvadorAbsent, No presence record(s)Jul-Dec-2019
GuatemalaAbsent, No presence record(s)Jan-Jun-2019
HaitiAbsent, No presence record(s)Jul-Dec-2019
HondurasAbsent, No presence record(s)
JamaicaAbsent, No presence record(s)Jul-Dec-2018
NicaraguaAbsent, No presence record(s)Jul-Dec-2019
Saint Kitts and NevisAbsent, No presence record(s)
Saint LuciaAbsent, No presence record(s)Jul-Dec-2018
Saint Vincent and the GrenadinesAbsent, No presence record(s)Jan-Jun-2019
Trinidad and TobagoAbsentJan-Jun-2018
United StatesPresent


Cook IslandsAbsent, No presence record(s)Jan-Jun-2019
Federated States of MicronesiaAbsent, No presence record(s)Jan-Jun-2019
French PolynesiaAbsentJan-Jun-2019
Marshall IslandsAbsent, No presence record(s)Jan-Jun-2019
New CaledoniaAbsentJul-Dec-2019
New ZealandAbsentJul-Dec-2019
Papua New GuineaPresent, LocalizedJul-Dec-2018
VanuatuAbsent, No presence record(s)Jan-Jun-2019

South America

BrazilPresentJul-Dec-2019; in wild animals only
ColombiaAbsent, No presence record(s)Jul-Dec-2019
EcuadorAbsent, No presence record(s)Jul-Dec-2019
Falkland IslandsAbsent, No presence record(s)Jul-Dec-2019
French GuianaAbsent, No presence record(s)Jul-Dec-2019
GuyanaAbsent, No presence record(s)
ParaguayAbsent, No presence record(s)Jul-Dec-2019
PeruAbsent, No presence record(s)Jan-Jun-2019
SurinameAbsent, No presence record(s)Jan-Jun-2019
VenezuelaAbsent, No presence record(s)Jan-Jun-2019

Pathogen Characteristics

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The various species/genotypes of Trichinella are morphologically very similar. This is the main reason why the 10 species/genotypes have been recognized only very recently (see Murrell, 2000).

The males are 1-2 mm and the females 1-4 mm. The body is slender and the oesophageal region is not very much longer than the posterior part of the worm. The male has no spicules but a pair of lateral flaps. The muscle larvae measure 0.6-1.4 mm. See table in Murrell et al. (2000).

Hosts/Species Affected

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The infectivity to pigs and the resulting numbers of larvae per gram of muscle have been compared for some of the Trichinella species (Kapel and Gamble, 2000):

Trichinella spiralis - Highly infective (171.5 larvae/g)

Trichinella nativa - Lightly infective (0.15 larvae/g)

Trichinella britovi - Moderately infective (30.6 larvae/g)

Trichinella nelsoni - Moderately infective (58.6 larvae/g)

Trichinella murrelli - Lightly infective (2.4 larvae/g)

Trichinella pseudospiralis - Moderately infective (23.9 larvae/g)

Trichinella papuae - Not known, however, the worms were originally isolated from wild boars from Papua New Guinea (Pozio et al., 1999)

Host Animals

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Animal nameContextLife stageSystem
Aves (birds)
Mammalia (mammals)
Sus scrofa (pigs)Domesticated host; Wild hostPigs|All Stages

Economic Impact

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Trichinella rarely cause clinical infections in pigs or other domestic animals, however, due to the zoonotic behaviour and the serious or even fatal course of Trichinella infections in man, the most important economical losses are caused by the intensive Trichinella preventive programmes and routine meat inspections (see Pozio, 2000).


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The detection of Trichinella infections in food animals has recently been reviewed by Nöckler et al. (2000). They also discussed important issues like sample size and sample location. The most simple method is trichinoscopy, which is direct microscopy of small muscle samples pressed between two glass plates (see Roepstorff and Nansen, 1998). This method is rather insensitive, has difficulties in recovering larvae of non-encapsulated species, and is time-consuming. Digestion with pepsin-HCl (see Roepstorff and Nansen, 1998; Nöckler et al., 2000) of pooled samples, is better but still rather time-consuming. Serodiagnostic methods (such as ELISA) have been developed, and are discussed by Nöckler et al. (2000).

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Infection of domestic pigs with Trichinella spp. may be due to ingestion of raw or inadequately cooked flesh (culinary waste) containing infective trichinae or accidental ingestion of infected rodents, such as rats (see Gajadhar and Gamble, 2000). Control of trichinellosis by inspection and farm management, the use of computerized databases in Trichinella control and international recommendations on control have been reviewed by Knapen (2000), Polley et al. (2000), and Gamble et al. (2000), respectively.


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Despommier DD, 1998. How does Trichinella spiralis make itself at home?. Parasitology Today, 14(8):318-323; 48 ref.

Gajadhar AA; Gamble HR, 2000. Historical perspectives and current global challenges of Trichinella and trichinellosis. Veterinary Parasitology, 93:183-189.

Gamble HR et al., 2000. International Commission on Trichinellosis: recommendations on methods for the control of Trichinella in domestic and wild animals intended for human consumption. Veterinary Parasitology, 93:393-408.

Kapel CMO, 2000. Host diversity and biological characteristics of the Trichinella genotypes and their effect on transmission. Veterinary Parasitology, 93:263-278.

Kapel CMO; Gamble HR, 2000. Infectivity, persistence, and antibody response to domestic and sylvatic Trichinella spp. in experimentally infected pigs. International Journal for Parasitology, 30(2):215-221; 35 ref.

Knapen F van, 2000. Control of trichinellosis by inspection and farm management practices. Veterinary Parasitology, 93:385-392.

Murrell KD; Lichtenfels JR; Zarlenga DS; Pozio E, 2000. The systematics of the genus Trichinella with a key to species. Veterinary Parasitology, 93:293-307.

Nöckler K; Pozio E; Voigt WP; Heidrich J, 2000. Detection of Trichinella infection in food animals. Veterinary Parasitology, 93:335-350.

OIE Handistatus, 2002. World Animal Health Publication and Handistatus II (dataset for 2001). Paris, France: Office International des Epizooties.

OIE Handistatus, 2003. World Animal Health Publication and Handistatus II (dataset for 2002). Paris, France: Office International des Epizooties.

OIE Handistatus, 2004. World Animal Health Publication and Handistatus II (data set for 2003). Paris, France: Office International des Epizooties.

OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (data set for 2004). Paris, France: Office International des Epizooties.

Polley L; Gaschler C; Gajadhar A, 2000. National occurrence reporting of Trichinella and trichinellosis using a computerized database. Veterinary Parasitology, 93(3/4):351-363; 17 ref.

Pozio E, 2000. Factors affecting the flow among domestic, synanthropic and sylvatic cycles of Trichinella. Veterinary Parasitology, 93(3/4):241-262; many ref.

Pozio E; La Rosa G; Amati M, 1994. Factors influencing the resistance of Trichinella muscle larvae to freezing. In: Campbell WC, Pozio E, Bruschi F, eds. Trichinellosis. Rome, Italy: Instituto Superiore di Sanita Press, 173-178.

Pozio E; La Rosa G; Yamaguchi T; Saito S, 1996. Trichinella britovi from Japan. Journal of Parasitology, 82:847-849.

Pozio E; Miller I; Järvis T; Kapel CMO; Rosa Gla, 1998. Distribution of sylvatic species of Trichinella in Estonia according to climate zones. Journal of Parasitology, 84(1):193-195; 10 ref.

Pozio E; Owen IL; Rosa Gla; Sacchi L; Rossi P; Corona S, 1999. Trichinella papuae n.sp. (Nematoda), a new non-encapsulated species from domestic and sylvatic swine of Papua New Guinea. International Journal for Parasitology, 29(11):1825-1839; 31 ref.

Roepstorff A; Nansen P, 1998. The epidemiology, diagnosis and control of helminth parasites of swine. An FAO handbook. Rome, Italy: FAO.

Soulsby EJL, 1982. Helminths, arthropods and protozoa of domesticated animals. Helminths, arthropods and protozoa of domesticated animals., Ed. 7:xi + 809 pp.44; [many fig., 260 x 195 mm]; many ref.

Zarlenga DS; Rosa G La, 2000. Molecular and biochemical methods for parasite differentiation within the genus Trichinella. Veterinary Parasitology, 93:279-292.

Distribution References

OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (dataset for 2004)., Paris, France: Office International des Epizooties.

OIE, 2018. World Animal Health Information System (WAHIS): Jul-Dec. In: OIE-WAHIS Platform, Paris, France: OIE (World Organisation for Animal Health). unpaginated.

OIE, 2018a. World Animal Health Information System (WAHIS): Jan-Jun. In: OIE-WAHIS Platform, Paris, France: OIE (World Organisation for Animal Health). unpaginated.

OIE, 2019. World Animal Health Information System (WAHIS): Jul-Dec. In: OIE-WAHIS Platform, Paris, France: OIE (World Organisation for Animal Health). unpaginated.

OIE, 2019a. World Animal Health Information System (WAHIS): Jan-Jun. In: OIE-WAHIS Platform, Paris, France: OIE (World Organisation for Animal Health). unpaginated.

OIE, 2020. World Animal Health Information System (WAHIS): Jul-Dec. In: OIE-WAHIS Platform, Paris, France: OIE (World Organisation for Animal Health). unpaginated.

OIE, 2020a. World Animal Health Information System (WAHIS). Jan-Jun. In: OIE-WAHIS Platform, Paris, France: OIE (World Organisation for Animal Health). unpaginated.

Distribution Maps

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