Enterobius vermicularis PCR test for primates

Enterobius vermicularis is a small parasitic roundworm commonly known as the pinworm, threadworm, or seatworm. It is one of the most prevalent human helminth infections worldwide, primarily affecting children in crowded environments like schools, though it can occur in people of any age. Humans are the only natural host for this parasite. Captive nonhuman primates can occasionally become infected through contact with humans, but they do not serve as a primary reservoir for transmission back to humans.

Adult female pinworms are approximately 8-13 mm long with a characteristic long and pointed tail, while males are smaller, approximately 2-5 mm long, and have a curved posterior end. The worms are thin, white or light gray, and threadlike in appearance. Eggs are oval-shaped with a dimension of about 50-60 μm by 20-30 μm and are often flattened on one side.

Infection of humans results in enterobiasis. The parasite spreads via the fecal-oral route. Female worms migrate to the perianal area at night to lay eggs, which can cause intense itching. Scratching leads to eggs being transferred to hands or under fingernails. This can lead to reinfection or spread to others through contaminated surfaces, bedding, or food. Eggs are highly infectious and can survive for weeks in the environment. The life cycle completes in the human intestine, where larvae hatch, mature, and reproduce without needing an intermediate host.

Many infections are asymptomatic. Common symptoms include perianal itching (especially at night), restlessness, insomnia, and sometimes abdominal pain or vaginal irritation in females. In rare cases, appendicitis can result from worms enter the appendix. Prevention of infection relies on good personal hygiene, such as frequent handwashing, trimming nails, washing bedding, and avoiding scratching the affected area.

Diagnosis of this parasitic infection is traditionally done using the "tape test," where clear adhesive tape is applied to the perianal skin in the morning to collect eggs for microscopic examination. However, the tape test has low sensitivity and low patient compliance. Polymerase chain reaction can be performed on fecal samples and has high sensitivity and specificity; thus, it can be preferable to the traditional diagnostic method and can also be used for environmental surveillance (Ummarino et al., 2022; Zelck et al., 2011).

Utilities:

Help confirm the presence of Enterobius vermicularis in NHPs or environmental samples
Selection of appropriate remediation regimens
Check for post-remediation absense of this parasite
Help minimize human exposure to this parasite

References:

Ummarino A, Caputo M, Tucci FA, Pezzicoli G, Piepoli A, Gentile A, Latiano T, Panza A, Calà N, Ceglia AP, Pistoio G, Troiano V, Pucatti M, Latiano A, Andriulli A, Tucci A, Palmieri O. A PCR-based method for the diagnosis of Enterobius vermicularis in stool samples, specifically designed for clinical application. Front Microbiol. 2022 Nov 17;13:1028988.

Zelck UE, Bialek R, Weiss M. Molecular phylogenetic analysis of Enterobius vermicularis and development of an 18S ribosomal DNA-targeted diagnostic PCR. J Clin Microbiol. 2011 Apr;49(4):1602-4.

Specimen requirements: 2 ml of feces; or rectal swab; 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 polymerase chain reaction

Normal range: Nondetected