Trichuris trichiura: Infectious substances Pathogen Safety Data Sheet

Section I: Infectious agent


Trichuris trichiura

Agent type









Synonym or cross reference

Trichuris trichiura is commonly known as whipworm.Footnote 1 Historical synonyms include Trichocephalus trichiurusFootnote 2, Trichocephalus disparFootnote 3, and Trichocephalus hominis.Footnote 4 Infection and disease associated with T. trichiura is termed trichuriasis, trichocephaliasis, or soil-transmitted helminthiasis.Footnote 5Footnote 6Footnote 7


Brief description

T. trichiura is a gastrointestinal nematode.Footnote 5 Adult worms are 2-5 cm in length and morphologically resemble a whip, with the esophagus located at the slender, filiform anterior end, known as the stichosome, and the anus at the broader posterior end.Footnote 7Footnote 8Footnote 9 Female worms are larger than males and have a straight posterior end, whereas the males have a coiled posterior.Footnote 1Footnote 10 The characteristic barrel-shaped eggs of T. trichiura are approximately 55 µm by 20 µm in size with transparent bipolar plugs, a vitelline membrane, and a triple shell, the outermost layer of which is brown.Footnote 7Footnote 9 Variation in egg shape, size, and colour has been reported.Footnote 11


The T. trichiura life cycle begins with ingestion of embryonated eggs, which hatch and release larvae that moult in the small intestine.Footnote 7 The larvae attach to the intestinal villi through burrowing of the anterior end into the mucosal epithelia, with the posterior end protruding into the lumen.Footnote 1Footnote 5Footnote 7 Adult whipworms develop within 3 months and reside in the large intestine, predominantly in the cecum but also in the ascending colon and rectum.Footnote 1Footnote 7 Adult worms may survive in the human intestine for several years, and after mating, the female worms can produce thousands of eggs per day, which are excreted in feces.Footnote 1Footnote 5 Upon shedding into the environment, the unembryonated eggs are initially non-infectious.Footnote 5 Embryonation takes several weeks and can vary depending on the environmental conditions; ideal conditions include shaded, warm, and moist soil.Footnote 8

Section II: Hazard identification

Pathogenicity and toxicity

T. trichiura is the etiological agent of the parasitic disease trichuriasis, which predominantly affects humans, but is also reported to affect some species of non-human primates.Footnote 1Footnote 9 Clinical disease results from the burrowing of adult worms into the intestinal mucosa, which causes petechial lesions, mucosal hemorrhage (i.e., blood loss), oozing, and inflammation.Footnote 7 The severity of clinical disease is related to the parasitic burden (i.e., the number of worms infecting an individual).Footnote 5 The World Health Organization (WHO) defines light T. trichiura infection as 1-999 eggs per gram (epg) of feces, moderate infection as 1,000-9,999 epg, and heavy infection as ≥10,000 epg.Footnote 12 Light infections are commonly asymptomatic, whereas clinical signs of moderate infection include abdominal pain and discomfort, diarrhea, vomiting, flatulence and distention, asthenia, headache, weight loss or stunting, and increased blood and iron loss.Footnote 1Footnote 7Footnote 8Footnote 13Footnote 14 Clinical features of heavy infection, often termed trichuris dysentery syndrome, include bloody mucoid diarrhea, rectal prolapse, colitis, intussusception (i.e., bowel obstruction), colonic perforation, cachexia, eosinophilia, severe iron deficiency anemia, severe stunting, and clubbing of the fingers.Footnote 1Footnote 7Footnote 8Footnote 13Footnote 14 The estimated mean daily blood loss per worm is 0.005 mL.Footnote 5 In children, chronic heavy infection is associated with malnutrition, growth retardation, and impaired mental development and cognitive function.Footnote 15Footnote 16 Infected individuals may also exhibit non-specific symptoms such as nervousness, anorexia, and urticaria.Footnote 5Footnote 8 Co-infection with other soil-transmitted helminths, namely roundworms and hookworms, is frequently observed.Footnote 8 Death resulting from trichuriasis is unlikely, although no reliable estimates of mortality exist.Footnote 5 As such, disease burden is typically quantified by years lived with disability (YLD).Footnote 17 The estimated YLD for trichuriasis in 2017 was 212,700, and has been steadily declining since the 1990s.Footnote 17 Similar to humans, clinical signs of trichuriasis in non-human primates range from asymptomatic to diarrhea, lethargy, abdominal pain, and weight loss.Footnote 18

Predisposing factors

The WHO has identified young children (12-23 months of age), preschool (24-59 months of age) and school-age children (5-12 years of age), adolescent girls (10-19 years of age), women of reproductive age (15-49 years of age), and pregnant women as population groups at risk of soil-transmitted helminth infections.Footnote 19 Susceptibility to infection may be influenced by behavioural, environmental, genetic, and immunological factors.Footnote 5 Positivity for T. trichiura was higher among children living in poor families and practicing open defecation.Footnote 20 Morbidity is most likely to occur in children with moderate to heavy infections.Footnote 5 Clustering of infection in overcrowded households and familial predisposition have been identified.Footnote 21Footnote 22 Some epidemiological studies suggest that previously infected individuals are at greater risk of reinfection following chemotherapy than uninfected individuals.Footnote 5 Evidence suggests that children of mothers with trichuriasis are at increased susceptibility to soil-transmitted helminth infection during early childhood.Footnote 23 Agricultural use of human excreta as fertiliser has been associated with higher risk of T. trichiura infection.Footnote 24 Pregnant women with moderate to heavy trichuriasis were found to be at higher risk of anemia.Footnote 25 Caretakers of non-human primates may be at higher risk of T. trichiura infection.Footnote 26


T. trichiura is a soil-transmitted helminth that spreads through the fecal-oral route.Footnote 7 Female adult worms can lay thousands of eggs daily for several years in the intestines of an infected host, which are shed into the environment through feces.Footnote 7 Upon excretion, the eggs are initially unembryonated and non-infectious, thus direct human-to-human or animal-to-animal transmission does not occur.Footnote 5 Transmission requires embryonation of eggs in warm, moist soil over the course of several weeks, where they can survive for months, followed by ingestion of the embryonated eggs via contaminated hands, food, water, soil, or fomites.Footnote 5Footnote 7Footnote 8Footnote 27 Upon ingestion by a new host, the embryonated eggs hatch, releasing larvae that moult in the small intestine and establish infection by burrowing into the host intestinal mucosa.Footnote 5Footnote 7


Human infection by T. trichiura is long-standing, as evidenced by detection of the parasite in archaeological human specimens dating back thousands of years.Footnote 5Footnote 28 Human T. trichiura infection remains prevalent worldwide, and is most common in warm, moist, tropical and subtropical regions, particularly those where access to water, sanitation, and hygiene is poor.Footnote 5Footnote 7Footnote 8 In 2017, the global prevalence of human T. trichiura infection was estimated to be almost 290 million, with approximately 96% of these cases representing asymptomatic infection.Footnote 17 Infection prevalence and intensity is highest among children, particularly those less than 15 years of age, with a decline in prevalence in adulthood.Footnote 5Footnote 7 T. trichiura is also prevalent among certain indigenous populations.Footnote 29Footnote 30 T. trichiura is non-endemic in Canada, although imported cases have been reported.Footnote 7Footnote 31 The prevalence of T. trichiura among non-human primates is typically high, and appears to be more common among captive animals.Footnote 26Footnote 32Footnote 33Footnote 34

Host range

Natural host(s)

The primary hosts of T. trichiura are humansFootnote 7 and non-human primates, including monkeysFootnote 33Footnote 34, chimpanzeesFootnote 32, and baboons.Footnote 33 T. trichiura eggs were reportedly detected in stool samples from dogs, although canine whipworm infections are generally considered to be T. vulpis.Footnote 35

Other host(s)

Humans and non-human primates have been infected with T. trichiura under experimental conditions.Footnote 36Footnote 37 Experimental infection of pigs with T. trichiura has also been reported, although adult worms rarely persist in this host.Footnote 38

Infectious dose

The minimum infectious dose for T. trichiura is unknown. Experimental self-infection in a human volunteer was achieved through ingestion of six hundred infective T. trichiura eggs.Footnote 37 Experimental infection of macaques was achieved through ingestion of 1,000 T. trichiura eggs.Footnote 36

Incubation period

Patent infections develop within 3 months following ingestion of embryonated T. trichiura eggs.Footnote 1Footnote 5 Adult worms can survive for 1-8 years in the intestines of infected hosts, and female worms can lay thousands of eggs daily, which are shed in feces.Footnote 5

Section III: Dissemination


Humans and non-human primates.Footnote 5Footnote 26Footnote 34

Zoonosis/Reverse zoonosis

Evidence suggestive of T. trichiura transmission between humans and non-human primates has been reported.Footnote 26Footnote 34


Cockroaches and houseflies may act as mechanical vectors of T. trichiura.Footnote 39

Section IV: Stability and viability

Drug susceptibility

Intestinal anthelminthics on the WHO List of Essential Medicines include albendazole, ivermectin, levamisole, mebendazole, niclosamide, praziquantel, and pyrantel.Footnote 12 Single dose treatment with most anthelminthic drugs, particularly benzimidazoles (e.g., albendazole and mebendazole), shows relatively poor efficacy against T. trichiura when compared to other soil-transmitted helminth infections.Footnote 5Footnote 40 However, efficacy improves with repeated dosing over several days.Footnote 5 Although it is no longer widely marketed, oxantel pamoate shows promising efficacy against T. trichiura, particularly when administered in combination with albendazole.Footnote 5

Drug resistance

Some studies suggest the progressive decrease in efficacy of benzimidazoles against T. trichiura may be related to the emergence of drug resistanceFootnote 40; however, conclusive evidence is currently lacking.Footnote 5

Susceptibility to disinfectants

Treatment with calcium hypochlorite (0.6 g/L) resulted in a 99.5% reduction in T. trichiura egg viability.Footnote 41

Physical inactivation

T. trichiura eggs perish below -9°C and above 52°C, and will not develop in direct sunlight.Footnote 8 Non-larval and larval T. trichiura eggs in sludge are inactivated by exposure to 80°C for a minimum of 120 minutes and 60°C for 60 minutes, respectively.Footnote 42

Survival outside host

T. trichiura eggs are excreted in feces and embryonate in warm, moist, and shaded soil, where they can survive for months.Footnote 7Footnote 8

Section V: First aid/medical


Soil-transmitted helminth infections, including trichuriasis, are traditionally diagnosed by microscopic observation of eggs in stool samples and quantified as epg of feces.Footnote 12 The WHO has recommended the Kato-Katz methodFootnote 43 as the diagnostic standard for quantification of T. trichiura eggs in fecal samples.Footnote 12 Other microscopy-based diagnostic techniques include the formol-ether concentration, FLOTAC and mini-FLOTAC, FECPAK, and McMaster methods.Footnote 5 Molecular-based diagnostic methods have also been developed, such as quantitative polymerase chain reaction (qPCR) and loop-mediated isothermal amplification (LAMP) assays, but these require specialized equipment and skilled technicians, and are therefore not widely used in endemic regions.Footnote 5Footnote 12 T. trichiura infection has also been diagnosed incidentally during colonoscopy.Footnote 10

Note: The specific recommendations for surveillance in the laboratory should come from the medical surveillance program, which is based on a local risk assessment of the pathogens and activities being undertaken, as well as an overarching risk assessment of the biosafety program as a whole. More information on medical surveillance is available in the Canadian Biosafety Handbook.

First aid/treatment

Recommended treatments for human T. trichiura infection include albendazole 400 mg once daily for 3 days, mebendazole 500 mg once daily for 3 days, or mebendazole 100 mg twice daily for 3 days.Footnote 7 Alternative therapies include ivermectin 200 µg/kg once daily for 3 days, or pyrantel embonate 11 mg/kg (not exceeding 1 g) once daily for 3 days.Footnote 7 Iron supplementation and supportive treatment should be considered for severe anemic cases (e.g., trichuris dysentery syndrome).Footnote 7 Infected non-human primates can be similarly treated with benzimidazoles (e.g., albendazole or mebendazole) or macrocyclic lactones (e.g., ivermectin).Footnote 44

Note: The specific recommendations for first aid/treatment in the laboratory should come from the post-exposure response plan, which is developed as part of the medical surveillance program. More information on the post-exposure response plan can be found in the Canadian Biosafety Handbook.


No vaccine is currently available; however, research into the development of vaccines against T. trichiura infection is ongoing.Footnote 5

Note: More information on the medical surveillance program can be found in the Canadian Biosafety Handbook, and by consulting the Canadian Immunization Guide.


The primary public health control strategy for soil transmitted helminth infections involves preventative chemotherapy through mass drug administration in endemic areas to at-risk populations without prior diagnosis, typically with single dose benzimidazoles annually or biannually.Footnote 19

Note: More information on prophylaxis as part of the medical surveillance program can be found in the Canadian Biosafety Handbook.

Section VI: Laboratory hazards

Laboratory-acquired infections

None reported to date. Since embryonation of T. trichiura eggs takes several weeks following excretion, laboratory-acquired infection resulting from exposure to recently collected fecal samples is unlikely.Footnote 45

Note: Please consult the Canadian Biosafety Standard and Canadian Biosafety Handbook for additional details on requirements for reporting exposure incidents. A Canadian biosafety guideline on notification and reporting procedures is also available.


Fecal samples containing infective (i.e., embryonated) eggs.Footnote 45

Primary hazards

Ingestion of infective eggs.Footnote 45

Special hazards


Section VII: Exposure controls/personal protection

Risk group classification

T. trichiura is a Risk Group 2 human pathogen and Risk Group 2 animal pathogen.Footnote 46

Containment requirements

Containment Level 2 facilities, equipment, and operational practices outlined in the Canadian Biosafety Standard for work involving infectious or potentially infectious materials, animals, or cultures.

Protective clothing

The applicable Containment Level 2 requirements for personal protective equipment and clothing outlined in the Canadian Biosafety Standard to be followed. At minimum, use of a labcoat and closed-toes cleanable shoes, gloves when direct skin contact with infected materials or animals is unavoidable.

Note: A local risk assessment will identify the appropriate hand, foot, head, body, eye/face, and respiratory protection, and the personal protective equipment requirements for the containment zone must be documented.

Other precautions

All activities that may produce aerosols, or involve high concentrations or large volumes are to be conducted in a biological safety cabinet (BSC) or other primary containment devices. The use of needles, syringes, and other sharp objects to be strictly limited. Additional precautions must be considered with work involving animals or large scale activities.

Section VIII: Handling and storage


Allow aerosols to settle. Wearing protective clothing, gently cover the spill with absorbent paper towel and apply suitable disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up (Canadian Biosafety Handbook).


All materials/substances that have come in contact with the infectious agent should be completely decontaminated before they are removed from the containment zone. This can be achieved by using decontamination technologies and processes that have been demonstrated to be effective against the infectious material, such as chemical disinfectants, autoclaving, irradiation, incineration, an effluent treatment system, or gaseous decontamination (Canadian Biosafety Handbook).


The applicable Containment Level 2 requirements for storage outlined in the Canadian Biosafety Standard to be followed. Containers of infectious material or toxins stored outside the containment zone must be labelled, leakproof, impact resistant, and kept either in locked storage equipment or within an area with limited access.

Section IX: Regulatory and other information

Canadian regulatory context

Controlled activities with Trichuris trichiura require a Human Pathogens and Toxins Licence issued by the Public Health Agency of Canada.Footnote 47 The following is a non-exhaustive list of applicable designations, regulations, or legislations:

Non-Indigenous Animal Pathogen or OIE-listed disease (please contact the Canadian Food Inspection Agency)


August, 2021

Prepared by

Centre for Biosecurity, Public Health Agency of Canada.


The scientific information, opinions, and recommendations contained in this Pathogen Safety Data Sheet have been developed based on or compiled from trusted sources available at the time of publication. Newly discovered hazards are frequent and this information may not be completely up to date. The Government of Canada accepts no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information.

Persons in Canada are responsible for complying with the relevant laws, including regulations, guidelines and standards applicable to the import, transport, and use of pathogens in Canada set by relevant regulatory authorities, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment and Climate Change Canada, and Transport Canada. The risk classification and related regulatory requirements referenced in this Pathogen Safety Data Sheet, such as those found in the Canadian Biosecurity Standard, may be incomplete and are specific to the Canadian context. Other jurisdictions will have their own requirements.

Copyright ©

Public Health Agency of Canada, 2021



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