Thursday, May 15, 2014

Neglected parasitic infections - what every family doc should know

- Jennifer Middleton, MD, MPH

The phrase "parasitic infections" probably brings to mind tropical locales and medical mission work, but the May 15th AFP article, "Neglected Parasitic Infections: What Every Family Physician Needs to Know," describes the Centers for Disease Control and Prevention's (CDC) effort to raise awareness of these infections in the United States. The authors review the 5 neglected parasitic infections (NPIs) that the CDC is focusing on:

Trypansoma cruzi is transmitted by triatomine bugs, which live in mud walls and thatched roofs in Central and South America. Infections in the US occur in persons who acquired the disease in those areas prior to entering the US. T. cruzi infection is asymptomatic for years but can later cause heart failure and gastrointestinal problems. Triatomine bugs have been found in the southern 1/2 of the US, and CDC researchers are working to determine if transmission is happening in the US as well.

Taenia solium, or pork tapeworms, are transmitted via the fecal-oral route. T. solium eggs travel to the brain and form cysts which can cause seizures. Approximately 1,000 persons are hospitalized with neurocysticercosis in the US every year, with most cases to date in New York state, Illinois, California, Oregon, and Texas.

Humans accidentally ingest Toxocara eggs from dog or cat feces. The two most severe forms of the disease, which typically affect children, can cause blindness and liver disease. According to the CDC, NHANES III data showed that 13.9% of the US population has antibodies to Toxocara. Deworming infected cats and dogs along with good hand hygiene can limit the spread of toxocariasis.

T. gondii is transmitted in cat feces and undercooked meat. Pregnant women who contract it are at risk of miscarrying. The CDC is working to improve diagnostic tests and also to develop a vaccine for cats against T. gondii.

The most common STD in the US, trichomoniasis is asymptomatic in 70% of cases. Infection with T. vaginalis increases the risk of infection by subsequent STDs (including HIV) and can also contribute to pre-term births. 

The CDC's webpage, "Neglected Parasitic Infections (NPIs) in the United States," describes the CDC's efforts to educate physicians and the public, provide testing and treatment recommendations, and bolster research to better understand these diseases. There is a wealth of information there, as well as at this hyperlink to the American Journal of Tropical Medicine and Hygiene's special section on NPIs in their May 2014 issue.

Has your practice seen any of these parasitic infections?