A Synopsis of AFP's "Neglected Parasitic Infections: What Every Family Physician Needs to Know"

Neglected Parasitic Infections: What Every Family Physician Needs to Know
DANA WOODHALL, MD; JEFFREY L. JONES, MD, MPH; PAUL T. CANTEY, MD, MPH; PATRICIA P. WILKINS, PhD; and SUSAN P. MONTGOMERY, DVM, MPH, Centers for Disease Control and Prevention, Atlanta, Georgia
Am Fam Physician. 2014 May 15;89(10):803-811

     This article will focus on four parasitic infections; Chagas disease, toxocariasis, cysticercosis, and toxoplasmosis. Chagas disease is caused from the parasite Trypanosoma cruzi. The CDC lifecycle can be found HERE. In a nutshell, a "kissing" bug (triatomine) bites a human and infects him or her with the parasite that it contracted from biting another human. It can also be spread through blood transfusion, organ transplantation, contaminated food, or congenitally. It is endemic to Mexico, Central and South America. It is usually asymptomatic, but it can cause conduction problems, heart failure, megacolon, megaesophagus, stroke, or cardiac disease. Treatment consists of Benznidazole and nifurtimox. Pregnant patients should not be treated because of adverse side effects. Congenital infections include anemia, low birth weight, low Apgar scores, thrombocytopenia, myocarditis, encephalitis, or hepatosplenomegaly. 
     Toxocariasis is caused by roundworms Toxocara canis and T. Cati. The CDC lifecycle can be found HERE. Humans become infected by either eating contaminated, undercooked meat, or by ingesting soil that has been contaminated with parasitic eggs from infected dogs or cats. Most patients are asymptomatic (covert toxocariasis). Young children (2-4 years old) present with visceral toxocariasis, an inflammatory response characterized by fever, wheezing, coughing, abdominal pain, anorexia, and fatigue. Older children (5-8 years old) may present with ocular manifestations including strabismus, granulomas, granulomatous masses, vision loss, or granulomas with traction bands. Serological testing is available. Treatment includes albendazole and mebendazole, with steroids it there is inflammation. 
     Cysticercosis is caused by an infection from the parasite Taenia Solium. The lifecycle can be found on the CDC website HERE. There are two cycles to this parasite. Humans can be infected by eating infected, undercooked pork, which manifest as intestinal tapeworms. Humans can also be infected through fecal-oral contact with the feces of other infected humans (which will contain eggs). The eggs with hatch and develop cysterci in various organs, including muscle, brain, and eyes. Symptoms include cysterci lumps under the skin, seizures, meningitis, headaches, intracranial hypertension, or hydrocephalus. Diagnosis is done with serology and imaging. Treatment consists of symptomatic control, steroids, and albendazole.
     Toxoplasmosis is due to an infection with Toxoplasma gondii. The CDC chart can be found HERE. Humans are infected through ingestion of raw, contaminated meat, contaminated water, or fruits and vegetables contaminated with cat feces (in the soil). Cats can shed parasites in their feces (we have all heard about pregnant women and litter boxes). Most patients are asymptomatic, but some may present with flu-like symptoms or encephalitis. Congenital toxoplasmosis can result in a miscarriage. Testing includes immunoglobulin serology and a toxoplasma avidity test. Amniotic fluid can be tested as early as 18 weeks gestation. Treatment is usually not necessary, but when it is, Pyrimethamine, sulfadiazine or leucovorin are used.