How Are Parasitic Diseases Diagnosed?
For diagnosis and subsequent treatment of parasitic infections, a thorough history for onset, signs and symptoms, travel, etc., is explored in addition to a careful physical exam that can identify rashes, bite marks, entrance sites, or eruptions.
Diagnosis of parasitic infections is initially prompted by signs and symptoms:
- Gastrointestinal: Weight loss, anorexia, nausea/vomiting, abdominal pain and bloating, rectal itching, and bloody or unremitting diarrhea with dehydration.
Stool exam for eggs, larva, and actual organisms or worms to identify helminths or protozoa, including Giardia, Cryptosporidium, E. histolytica, and Blastocystis hominis.
- Pulmonary: pneumonitis, persistent cough, or breathing difficulties, such as from Toxoplasmosis.
Serologic tests for the IgG, IgM, IgA, and IgE immunoglobulins that test for Toxoplasma gondii exposure and infection. Bronchoscopy may be necessary.
- Dermatological: skin rashes, eruptions, itching, and swelling of superficial lymph nodes, as well as secondary bacterial infections of bites.
- Neurological: cognitive impairments due to central nervous system parasites, such as Angiostrongylus cantonensis, Gnathostomiasis, Baylisascariasis, toxocariasis, trichinellosis, and others.
Blood tests can identify anemia or eosinophilia (a type of white blood cell elevation often occurring in parasitic infections). Examination of red blood cells can identify malaria and other blood disorders.