Clinician's Corner - Minnesota Department of Health

Parasitic Infections Quick Guide

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Screening and Diagnosis
Full Provider Guide Chapter: Parasites

Screening and Diagnosis

Common Parasites

  • The geographic distribution of specific parasitic infections is varied. All information such as country of origin, refugee migration, food habits, lack of shoes, lack of safe drinking water, quality of sanitation, and history of insect bites may be helpful in ruling in or ruling out certain parasitic infections.
  • The most commonly found pathogenic parasites are Trichuris (whipworm), Giardia, Entamoeba histolytica, Schistosoma, hookworm, and Ascaris.
  • Lice and scabies mites are two common arthropod parasites often found in refugee populations.
  • Parasites may obstruct the intestine, bile ducts, lymph channels, and capillaries of the brain and other organs, with serious medical consequences.


  • Assess for pre-departure presumptive treatment; screen per protocol based on whether or not such treatment was received and type of treatment administered overseas. For current overseas programs and populations affected, see CDC's Guidelines for the U.S. Domestic Medical Examination for Newly Arriving Refugees. If results are not provided by the state at the time of screening, ask refugees to bring blue and white IOM bag and look for documentation in that bag. Attention: Non-MDH link
  • Screening for parasitic infection in asymptomatic refugees
    • No documented pre-departure treatment:
      • Presumptive therapy or serologies for strongyloides (all refugees), serologies for schistosomaisis (sub-Saharan African refugees), stool ova & parasite examination* and absolute eosinophil count.**
    • Received single-dose pre-departure albendazole +/- praziquantel:
      • Presumptive therapy or serologies for strongyloides (all refugees), serologies for schistosomiasis (sub-Saharan African refugees who did not receive praziquantel) and/or absolute eosinophil count.**
    • Received high-dose pre-departure albendazole (7 days) or ivermectin +/- praziquantel:
      • Check absolute eosinophil count**

*Collecting specimens: When collecting more than one stool specimen, indicate that specimens should be obtained more than 24 hours apart. Provide detailed instruction about specimen collection and give kits to patients. If convenient, suggest that your patient bring back the stool specimen in two to three days, when s/he is returning for the tuberculosis skin test (TST) reading. Some clinics offer patients the option of mailing stool specimens directly to the lab.

**Eosinophil count is routinely recommended as part of the hematology testing and is not sensitive or specific for invasive parasites; however, a persistently elevated count demands further investigation.


  • Treat pathogenic parasites. If positive for pathogenic parasites or eosinophilia, a repeat absolute eosinophil count should be performed 3-6 months post-treatment.
  • If results are positive for either Strongyloides stercoralis (all refugees) or Schistosoma spp. (sub-Saharan African refugees), the refugee should be treated.
  • For positive results, discuss treatment with your patient. Describe how to get the prescription filled and how to take the medications. Prescribe through a pharmacy affiliated with your clinic to ensure that the patient is not billed for anti-parasitic medications.
  • If clinical history indicates, also test for bacterial enteric pathogens and treat appropriately.


  • At least one third of the world’s population may be infected with intestinal parasites, and all immigrant groups are affected to some degree by intestinal parasites (i). In Minnesota between 2004 -2008, 15-17 percent of primary refugees tested positive for pathogenic parasitic infection (ii).
  • Strongyloides stercoralis, which is found in almost all refugee groups, and Schistosomiasis spp, predominantly seen in sub-Saharan refugees, are two parasitic infections of particular concern. Most refugees with strongyloidiasis are asymptomatic. If left unchecked, this infection can persist for years, and under certain conditions can lead to a severe hyper-infection. Schistosomiasis is often asymptomatic initially; however, for people who are not treated and/or are repeatedly infected for many years, infection can cause damage to the liver, intestines, lungs and bladder (iii, iv).

Full Provider Guide Chapter: Parasites


i. Centers for Disease Control and Prevention. Domestic Intestinal Parasite Guidelines. Accessed July 8, 2009. Attention: Non-MDH link

ii. Minnesota Department of Health. Refugee health statistics. Accessed Oct. 29, 2009.

iii. Centers for Disease Control and Prevention. Domestic Intestinal Parasite Guidelines. Accessed July 8, 2009. Attention: Non-MDH link

iv. Mody R. Intestinal Parasites. In: Walker P, Barnett E, eds. Immigrant Medicine. Philadelphia, PA: Saunders Elsevier; 2007:273-307.

Updated Monday, November 28, 2011 at 02:04PM