Dogs and Cats Transmit Roundworms to Humans More Often Than Previously Believed

According to the Companion Animal Parasite Council (CAPC), a Centers for Disease Control and Prevention (CDC) study found that about 14 percent of the U.S. population is infected with Toxocara, or internal roundworms, contracted from dogs and cats. According to a press release, the results of the study were announced Nov. 6 at the American Society of Tropical Medicine and Hygiene in Philadelphia.

CAPC is a nonprofit organization that was formed to educate pet owners and parents of young children about zoonotic (animal to human) diseases. Toxocariasis is the zoonotic infection caused by roundworms or Toxocara.

Internal roundworms are parasites common to both dogs and cats. The eggs of roundworms are passed in the feces. Therefore, wherever contaminated feces is likely to be found, such as parks, playgrounds and sandboxes, the chances of a child's accidental ingestion of roundworms eggs are increased.

Roundworms transmission from dogs and cats is most common in young children and pet owners. CAPC says it's also found more often in less-educated and lower socioeconomic populations, probably because of either a lack of information or the inability to afford ongoing parasite control for their dogs and cats. However, where young children are concerned, there seems to be less discrimination in their susceptibility to infection because of their propensity to play in the dirt and eat or otherwise ingest contaminated soil.

The first line of defense for pet owners is to rid and prevent parasites in family pets. Michael Paul, DMV and executive director of CAPC says: "The CAPC recommends that pet owners administer year-round preventive medicines that control internal and external parasites - such as roundworms, heartworm, fleas and ticks - for the life of their dog or cat no matter where they live. If you prevent parasitic infections in companion animals, you greatly reduce the chances of zoonotic transmission to people."

Parasite control in dogs and cats is simple and effective. Both dogs and cats should be treated for parasites every month because the potential for exposure to roundworms and other parasites is there all year long, regardless of where one lives.

As far as roundworms infection (toxocariasis) goes, epidemiologist and veterinarian Peter Schantz says that although most people infected with Toxocara "have no apparent symptoms, this infectious agent is capable of causing blindness and other serious systemic illness, which makes it a public health issue." Schantz also said that because "toxocariasis is not a reportable infection, true numbers of cases of visual impairment and other syndromes are not known."

According to the CDC, roundworms infections are not serious in most cases. In fact, adults infected by a small number of roundworms larvae may not even notice any symptoms. When cases are severe, they are most likely to occur in children.

If a parent believes their child has been exposed to feces-contaminated dirt or sand, a consult with a physician is wise. Treatment for toxocariasis generally involves anti-parasitic drugs, sometimes combined with anti-inflammatory medications.

Sources:

Press release, CDC Reports Prevalence of Worms Transmitted by Dogs and Cats to Humans is Higher than Previously Understood; http://www.prweb.com/releases/2007/11/prweb567105.htm

CDC; http://www.cdc.gov/Ncidod/dpd/parasites/toxocara/factsht_toxocara.htm