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

Abstract

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.

FIGURE 1. The transmission cycle of Chagas disease.

Reprinted from Centers for Disease Control and Prevention. Parasites - American trypanosomiasis (also known as Chagas disease). Biology. Updated February 11, 2019. Accessed May 13, 2020. https://www.cdc.gov/parasites/chagas/biology.html

FIGURE 2. Algorithm for the evaluation of Chagas disease in pregnant patients.

FIGURE 3. The transmission cycle of cysticercosis.

Reprinted from Centers for Disease Control and Prevention. Parasites - cysticercosis. Biology. Updated September 22, 2020. Accessed May 13, 2020. https://www.cdc.gov/parasites/cysticercosis/biology.html

FIGURE 4. Diagnosis and management of neurocysticercosis in patients presenting with new seizures or increased intracranial pressure

*—Seizure and increased intracranial pressure are the most common presentations of neurocysticercosis; there may be other symptoms. †—Additional therapy may involve albendazole (Albenza), praziquantel (Biltricide), or both; surgical intervention for ventricular lesions; corticosteroids for perilesional edema; and treatment of Strongyloides infection if prolonged use of corticosteroids is anticipated.

FIGURE 5. The transmission cycle of toxoplasmosis.

Reprinted from Centers for Disease Control and Prevention. Parasites - toxoplasmosis. (Toxoplasma infection). Biology. Updated November 10, 2020. Accessed May 13, 2020. https://www.cdc.gov/parasites/toxoplasmosis/biology.html

FIGURE 6. Diagnosis and management of toxoplasmosis in people who are immunocompetent.

IG = immunoglobulin.