Neglected Parasitic Infections: What Family Physicians Need to Know—A CDC Update

 

Am Fam Physician. 2021 Sep ;104(2):277-287.

Related editorial: Parasitic Infections: Do Not Neglect Strongyloidiasis

Author disclosure: No relevant financial affiliations.

Chagas disease, cysticercosis, and toxoplasmosis affect millions of people in the United States and are considered neglected parasitic diseases. Few resources are devoted to their surveillance, prevention, and treatment. Chagas disease, transmitted by kissing bugs, primarily affects people who have lived in Mexico, Central America, and South America, and it can cause heart disease and death if not treated. Chagas disease is diagnosed by detecting the parasite in blood or by serology, depending on the phase of disease. Antiparasitic treatment is indicated for most patients with acute disease. Treatment for chronic disease is recommended for people younger than 18 years and generally recommended for adults younger than 50 years. Treatment decisions should be individualized for all other patients. Cysticercosis can manifest in muscles, the eyes, and most critically in the brain (neurocysticercosis). Neurocysticercosis accounts for 2.1% of all emergency department visits for seizures in the United States. Diagnosing neurocysticercosis involves serology and neuroimaging. Treatment includes symptom control and antiparasitic therapy. Toxoplasmosis is estimated to affect 11% of people older than six years in the United States. It can be acquired by ingesting food or water that has been contaminated by cat feces; it can also be acquired by eating undercooked, contaminated meat. Toxoplasma infection is usually asymptomatic; however, people who are immunosuppressed can develop more severe neurologic symptoms. Congenital infection can result in miscarriage or adverse fetal effects. Diagnosis is made with serologic testing, polymerase chain reaction testing, or parasite detection in tissue or fluid specimens. Treatment is recommended for people who are immunosuppressed, pregnant patients with recently acquired infection, and people who are immunocompetent with visceral disease or severe symptoms.

Neglected parasitic infections designated by the Centers for Disease Control and Prevention (CDC) include Chagas disease, cysticercosis, toxoplasmosis, toxocariasis, and trichomoniasis.1 These parasitic infections have been prioritized based on the number of people infected, the potential for severe illness, and availability of treatment regimens. This article reviews three infections that are typically not emphasized in medical training—Chagas disease, cysticercosis, and toxoplasmosis. Information on the others (toxocariasis and trichomoniasis) can be found on the CDC website.1  Despite the ability to cause severe illness, limited resources have been devoted to understanding the impact and burden of neglected parasitic infections. Family physicians should understand the basic principles of clinical presentation, diagnosis, and treatment of these diseases. A summary of key points for each disease is presented in Table 1.2

The Authors

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PAUL T. CANTEY, MD, MPH, is a medical officer in the Division of Parasitic Diseases and Malaria at the Centers for Disease Control and Prevention, Atlanta, Ga....

SUSAN P. MONTGOMERY, DVM, MPH, is a veterinary medical officer in the Division of Parasitic Diseases and Malaria at the Centers for Disease Control and Prevention.

ANNE STRAILY, DVM, MPH, is a veterinary medical officer in the Division of Parasitic Diseases and Malaria at the Centers for Disease Control and Prevention.

Address correspondence to Paul T. Cantey, MD, MPH, 1600 Clifton Rd., MS H24-3, Atlanta, GA 30329 (email: gdn9@cdc.gov). Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.

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