Trichostrongylus (hair worm)

Test code: X0057 - Ultrasensitive qualitative detection of Trichostrongylus by real time PCR

Trichostrongylus is a genus of parasitic roundworms belonging to the family Trichostrongylidae, commonly known as hairworm. These worms primarily infect the intestine of herbivores including cattle, sheep, goats, donkeys, deer, horses, pigs, poultry, and wild ruminants such as camels, antelopes, and zebras.

At least 10 species within the genus can infect humans as incidental hosts, often through ingestion of infective larvae present in water or vegetables contaminated by animal feces. Prevalence of human infection is highest in rural areas and in regions with poor sanitation. Farmers and herders are often infected by these worms. Infection of humans can lead to trichostrongyliasis; while most human infections are asymptomatic or mild, in severe cases gastrointestinal symptoms may occur.

Major species include T. colubriformis, T. vitrinus, T. axei, T. orientalis, and T. probolurus. They vary by host and geographic region. For example, T. axei often affects the abomasum (stomach) in ruminants and can cause gastritis, diarrhea, weight loss, and protein loss in heavy infections. Infection with these parasites can lead to conditions like parasitic gastroenteritis or black scour in sheep and goats.

These worms have a direct life cycle, without the need for an intermediate host. Adult females lay eggs in the intestine of infected animals. These eggs pass in feces into the environment, where they hatch into infective rhabditiform larvae. The definitive host becomes infected by consuming infective larvae while grazing on contaminated vegetation or drinking contaminated water. Once ingested, the larvae exsheath in the intestine and penetrate the mucosa of the small intestine or abomasum, where they mature into adults and begin reproducing to generate thousands of eggs.

Microscopic examination of feces to diagnose the parasitic infection has a low sensitivity. This method is also not suitable for environmental surveillance because the concentration of eggs in environmental samples like soil and water is usually very low, and distribution in these sample types is nonhomogeneous. Polymerase chain reaction is increasingly used to replace the traditional methods because it can provide species-specific detection with minimal sample volume, even in complex matrices where viable eggs are scarce or degraded (Pandi et al., 2021; Perandin et al., 2018).

Utilities:

• Help confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of Trichostrongylus infection
• Help ensure that herds are free of Trichostrongylus  
• Early prevention of spread of Trichostrongylus between animal species
• Minimize human exposure to Trichostrongylus

References:

Pandi M, Sharifdini M, Ashrafi K, Atrkar Roushan Z, Rahmati B, Hajipour N. Comparison of Molecular and Parasitological Methods for Diagnosis of Human Trichostrongylosis. Front Cell Infect Microbiol. 2021 Oct 13;11:759396.

Perandin F, Pomari E, Bonizzi C, Mistretta M, Formenti F, Bisoffi Z. Assessment of Real-Time Polymerase Chain Reaction for the Detection of Trichostrongylus spp. DNA from Human Fecal Samples. Am J Trop Med Hyg. 2018 Mar;98(3):768-771.

Specimen requirement: 2 ml of feces; or rectal swab; or 10 ml of soil; or 10 ml of water, or used water filter media; or environmental swabs or swipes.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time PCR

Normal range: Nondetected