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Chapter 3Infectious Diseases Related To Travel
Giardiasis
Sharon L. Roy, Michele C. Hlavsa
INFECTIOUS AGENT
Giardiasis is a diarrheal illness caused by the protozoan parasite Giardia intestinalis (formerly known as G. lamblia or G. duodenalis).
MODE OF TRANSMISSION
Transmission occurs by ingesting fecally contaminated food or water, including water swallowed while swimming. Infection can also occur after contact with fecally contaminated environmental surfaces and objects or during person-to-person contact, such as diaper changing, caring for an infected person, or sexual contact.
EPIDEMIOLOGY
Giardiasis transmission occurs worldwide. Risk of infection increases with duration of travel. From 1996 through 2005, 31.3 per 1,000 returned travelers seeking medical care at GeoSentinel-associated medical centers around the world were diagnosed with giardiasis. Giardiasis was most commonly diagnosed in travelers returning from south Asia, the Middle East, and South America, although travelers returning from all other regions were also affected. Long-term travelers (duration >6 months) were significantly more likely than short-term travelers (duration <1 month) to develop giardiasis. In studies of travelers and expatriates in Nepal, Giardia is found in about 10% of stool samples submitted by patients with diarrhea.
CLINICAL PRESENTATION
Symptoms usually begin 1–2 weeks after infection and are generally self-limiting within 2–4 weeks. Giardiasis can cause a variety of intestinal symptoms or signs, which include diarrhea (often with foul-smelling, greasy stools), abdominal cramps, bloating, flatulence, fatigue, anorexia, and nausea. Typically, a patient presents with the gradual onset of 2–5 loose stools per day and gradually increasing fatigue. Weight loss may occur over time. Fever and vomiting are uncommon. Rarely, reactive arthritis has occurred after infection with Giardia.
DIAGNOSIS
Giardia cysts or trophs are not consistently seen in the stools of infected patients. Diagnostic yield can be increased by examining up to 3 stool samples over several days. Enzyme immunoassays can also be used to detect Giardia antigen, but it is unclear if they increase the diagnostic sensitivity.
TREATMENT
Several antimicrobial drugs, including tinidazole, metronidazole, nitazoxanide, paromomycin, furazolidone, and quinacrine are known to treat giardiasis (see Table 5-05). Because of the difficulty of making a definitive diagnosis, empiric treatment can be used in patients with the appropriate history and typical symptoms.
PREVENTIVE MEASURES FOR TRAVELERS
No vaccine is available to prevent giardiasis, and there is no recommended chemoprophylaxis. To prevent infection, travelers should be advised to follow food and water precautions described in Chapter 2, Food and Water Precautions.
BIBLIOGRAPHY
- Chen LH, Wilson ME, Davis X, Loutan L, Schwartz E, Keystone J, et al. Illness in long-term travelers visiting GeoSentinel clinics. Emerg Infect Dis. 2009 Nov;15(11):1773–82.
- Freedman DO, Weld LH, Kozarsky PE, Fisk T, Robins R, von Sonnenburg F, et al. Spectrum of disease and relation to place of exposure among ill returned travelers. N Engl J Med. 2006 Jan 12;354(2):119–30.
- Greenwood Z, Black J, Weld L, O’Brien D, Leder K, Von Sonnenburg F, et al. Gastrointestinal infection among international travelers globally. J Travel Med. 2008 Jul–Aug;15(4):221–8.
- Hill DR, Nash TE. Intestinal flagellate and ciliate infections. In: Guerrant RL, Walker DH, Weller PF, editors. Tropical Infectious Diseases. Philadelphia: Churchill Livingstone; 2006. p. 984–1002.
- Hill Gaston JS, Lillicrap MS. Arthritis associated with enteric infection. Best Pract Res Clin Rheumatol. 2003 Apr;17(2):219–39.
- Okhuysen PC. Traveler’s diarrhea due to intestinal protozoa. Clin Infect Dis. 2001 Jul 1;33(1):110–4.
- Swaminathan A, Torresi J, Schlagenhauf P, Thursky K, Wilder-Smith A, Connor BA, et al. A global study of pathogens and host risk factors associated with infectious gastrointestinal disease in returned international travellers. J Infect. 2009 Jul;59(1):19–27.
- Taylor DN, Houston R, Shlim DR, Bhaibulaya M, Ungar BL, Echeverria P. Etiology of diarrhea among travelers and foreign residents in Nepal. JAMA. 1988 Sep 2;260(9):1245–8.
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