They do not tolerate heat well, but can survive in low temperatures: at −8 degrees Celsius (18 °F), two-thirds of the eggs are still viable after 18 hours.After the eggs have been initially deposited near the anus, they are readily transmitted to other surfaces through contamination. The surface of the eggs is sticky when laid, and the eggs are readily transmitted from their initial deposit near the anus to fingernails, hands, night-clothing and bed linen. From here, eggs are further transmitted to food, water, furniture, toys, bathroom fixtures and other objects. Household pets often carry the eggs in their fur, while not actually being infected. Dust containing eggs can become airborne and widely dispersed when dislodged from surfaces, for instance when shaking out bed clothes and linen. Consequently, the eggs can enter the mouth and nose through inhalation, and be swallowed later. Although pinworms do not strictly multiply inside the body of their human host, some of the pinworm larvae may hatch on the anal mucosa, and migrate up the bowel and back into the gastrointestinal tract of the original host. This process is called retroinfection. According to Burkhart (2005), when this retroinfection occurs, it leads to a heavy parasitic load and ensures that the pinworm infestation continues. This statement is contradictory to a statement by Caldwell, who contends that retroinfection is rare and not clinically significant.
Pyrantel pamoate is the treatment of choice in pregnancy but should be used only after consultation with a health care practitioner rather than self-treatment. Treatment should be avoided in the first trimester, and if possible done in the third trimester. If the pregnant individual is asymptomatic, then they should be treated after the baby is delivered.Mebendazole has less than 10% of the oral dose absorbed into systemic circulation with a clinically insignificant amount of drug excreted in breastmilk, and therefore treatment should not be withheld during breastfeeding. There is limited data on the use of pyrantel pamoate and albendazole in breastfeeding but WHO also classifies them as compatible with breastfeeding. This is due to the drugs acting mainly in the intestinal system of the mother with only a very small amount of drug being absorbed into the systemic circulation. Epidemiology
Pinworm infection occurs worldwide, and is the most common helminth (i.e., parasitic worm) infection in the United States and Western Europe. In the United States, a study by the Center of Disease Control reported an overall incidence rate of 11.4% among people of all ages. Pinworms are particularly common in children with approximately 30% of children being infected and most commonly seen in children between 7 and 11 years old. The prevalence rates in children having been reported as high as 61% in India, 50% in England, 39% in Thailand, 37% in Sweden, and 29% in Denmark. Finger sucking has been shown to increase both incidence and relapse rates, and nail biting has been similarly associated.