View source for Helminth infections

==Background==
*Approximately 2 billion people infected worldwide
*Many are WHO-designated Neglected Tropical Diseases<ref>The 17 Neglected Tropical Diseases." World Health Organization.  http://www.who.int/neglected_diseases/diseases/en/.  Web. 11 Aug. 2014.</ref>
*At-risk populations include impoverished, children, immigrants, tourists, HIV/AIDS patients, refugees <ref name="CDC">"Parasites." Centers for Disease Control and Prevention.  http://www.cdc.gov/parasites/.  Web. 11 Aug. 2014.</ref>
*Most common in subtropical and tropical areas, moist climates, poor sanitation and hygiene <ref name="rosens">"Chapter 133 - Parasitic Infections." Rosen's Emergency Medicine: Concepts and Clinical Practice. Ed. John A. Marx, Robert S. Hockberger, and Ron M. Walls. Philadelphia, PA: Mosby Elsevier, 2014. 1768-784.</ref>

===Transmission:===
*No direct person-to-person transmission 

*Fecal-oral transmission (ingestion of eggs in contaminated soil / vegetables / water)<ref name="rosens"></ref>
**Ascaris and whipworm from human feces
**Toxocara from dog / cat feces
**Echinococcus from sheep / cattle feces
**Taenia eggs from human feces

*Cutaneous transmission
**Hookworm eggs hatch in the soil, mature larvae penetrate skin 
**Lymphatic filariasis transmitted via bite from infected mosquito (Anopheles, Aedes, and Culex)
**[[Onchocerciasis]] transmitted via bite from blackflies (Simulium species)

*Food or waterborne transmission
**Taenia also transmitted by ingestion of larval cysts in undercooked pork or beef
**Diphyllobothrium tapeworm transmitted by contaminated freshwater fish
**Dracunculiasis transmitted by ingestion of infected Cyclops water fleas in contaminated water (adult worm erodes through skin of leg, releases larvae in water when host wades in pond / open well, infecting the water fleas)

==Clinical Features==
===History===
*Parasitic infections can be in the differential diagnosis for nearly every sign/symptom (GI, dermatologic, neurologic, pulmonary, ophthalmologic, hematologic)

*Obtain a travel history in every patient
**countries of travel
**duration of stay
**activities while traveling (adventure travel, tourism, working, swimming)  
**living arrangements – city / village / hotel / tent
**drinking water source
**symptom chronology

==Types==
{{Helminth Types}}

==Evaluation==
===General===
*Stool studies (ova and parasites)
*CBC to identify peripheral [[eosinophilia]] or anemia (not sensitive or specific)
*Peripheral blood smear to identify microfilariae (e.g. lymphatic filariasis)

===Disease/Symptom Specific===
*Pulmonary symptoms: CXR and sputum smear (e.g. Löffler’s syndrome)
*CNS symptoms 
**Neuroimaging (CT with contrast or MR brain) may reveal ring-enhancing lesions, calcifications, or focal enhancing lesions in neurocysticercosis<ref>Del Brutto OH, Rajshekhar V, White A, et al.  “Proposed diagnostic criteria for neurocysticercosis.”  Neurology, 2001; 57:177-183.</ref><ref>Del Brutto OH.  “Diagnostic criteria for neurocysticercosis, revisited.”  Pathogens and Global Health, 2012; 106(5):299-304.</ref>
**CSF serologies/ELISA for echinococcus, cysticercosis
*Ultrasound or CT can localize cyst of echinococcus
*ELISA or biopsy of affected tissue to diagnosis toxocariasis, cysticercosis 
*Identification of adult worm or microscopic larvae in cutaneous ulcer fluid can confirm dracunculiasis

==Management==

==See Also==
*[[Parasitic Diseases]]
*[[Travel Medicine]]

==External Links==

==References==
<references/>

[[Category:ID]]