Chapter 3Infectious Diseases Related To Travel
Katherine E. Heiman, Anna Bowen
Shigellosis is an acute infection of the intestine caused by bacteria in the genus Shigella. There are 4 species of Shigella: Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei (also referred to as group A, B, C, and D, respectively). Several distinct serotypes are recognized within the first 3 species.
Transmission occurs via the fecal-oral route, through direct person-to-person contact, or indirectly through contaminated food, water, or fomites. As few as 10 organisms can cause infection. Only humans and higher primates carry Shigella. In the United States, S. sonnei infection is usually transmitted through interpersonal contact, particularly among young children in day care settings. Foodborne outbreaks have been linked to contaminated foods commonly consumed raw, as well as infected food handlers. Outbreaks have also been traced to contaminated drinking water, swimming in contaminated water, and sexual contact between men.
Worldwide, Shigella is estimated to cause 80–165 million cases of disease and 600,000 deaths annually. Shigella spp. are endemic in temperate and tropical climates. Transmission of Shigella spp. is most likely when hygiene and sanitation are insufficient. Shigellosis is predominantly caused by S. sonnei in industrialized countries, whereas S. flexneri prevails in the developing world. Infections caused by S. boydii are uncommon. S. dysenteriae is even more uncommon, but makes up ≥25% of all Shigella spp. isolated in sub-Saharan Africa and South Asia. Shigella spp. are detected in the stools of 5%–18% of patients with travelers’ diarrhea. In a FoodNet study of travel-associated enteric infections diagnosed after return to the United States, Shigella was the third most common bacterial pathogen isolated by clinical laboratories (of note, these laboratories do not test for enterotoxigenic Escherichia coli, a common cause of travelers’ diarrhea). Most infections caused by S. dysenteriae were travel-associated (56%). Many infections caused by S. boydii (44%) were acquired while traveling, but infections caused by S. flexneri and S. sonnei were less often associated with travel (24% and 12%, respectively). Risk of infection caused by Shigella spp. is highest for people traveling to Africa, followed by Central America, South America, and Asia.
Illness typically begins 12–96 hours after exposure. The symptoms of shigellosis range from mild to severe and typically last 4–7 days. Disease severity varies according to species; serotype S. dysenteriae serotype 1 (Sd1) is the agent of epidemic dysentery, while S. sonnei is a common cause of milder diarrheal illness. The disease is characterized by watery, bloody, or mucoid diarrhea, fever, stomach cramps, and nausea. Occasionally, patients experience vomiting, seizures (young children), or postinfectious arthritis. Hemolytic uremic syndrome can occur after infection with Sd1.
Shigellosis is confirmed through culture of a stool specimen or rectal swab. Samples should be processed rapidly because Shigella cannot survive for long outside the body. Shigella isolates may then be speciated and serotyped and their antimicrobial susceptibilities determined to help guide treatment.
In healthy people, shigellosis will typically resolve within 4–7 days, even without treatment. Antimicrobial treatment, when given early in the course of illness, can slightly shorten the duration of symptoms and of carriage. The possibility of resistance should be considered for patients in whom treatment is indicated. For shigellosis associated with travel outside the United States, a fluoroquinolone (for adults and, if infection is acquired in regions with high rates of multidrug resistance, children) or ceftriaxone (for children) may be used empirically until antimicrobial susceptibility data are available. However, resistance to fluoroquinolones and third- and fourth-generation cephalosporins has been reported, particularly among Shigella isolates acquired in South and East Asia. Multidrug-resistant strains are especially common among travelers; empiric treatment should be tailored to region of travel.
No vaccines are available for Shigella. The best defense against shigellosis is thorough, frequent handwashing and strict adherence to standard food and water safety precautions (see Chapter 2, Food & Water Precautions).
- American Academy of Pediatrics. Shigella infections. In: Pickering LK, editor. Red Book: 2012 Report of the Committee on Infectious Diseases. 29th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2012. p. 645–7.
- American Public Health Association. Shigellosis. In: Heymann DL, editor. Control of Communicable Diseases Manual. 19th ed. Washington, DC: American Public Health Association; 2008. p. 556–60.
- CDC. National Shigella surveillance system [annual summaries]. Atlanta: CDC; 2012 [cited 2012 Sep 21]. Available from: http://www.cdc.gov/nationalsurveillance/shigella_surveillance.html.
- Dutta S, Dutta P, Matsushita S, Bhattacharya SK, Yoshida S. Shigella dysenteriae serotype 1, Kolkata, India. Emerg Infect Dis. 2003 Nov;9(11): 1471–4.
- Folster JP, Pecic G, Bowen A, Rickert R, Carattoli A, Whichard JM. Decreased susceptibility to ciprofloxacin among Shigella isolates in the United States, 2006 to 2009. Antimicrob Agents Chemother. 2011 Apr;55(4):1758–60.
- Gaynor K, Park SY, Kanenaka R, Colindres R, Mintz E, Ram PK, et al. International foodborne outbreak of Shigella sonnei infection in airline passengers. Epidemiol Infect. 2009 Mar;137(3): 335–41.
- Haley CC, Ong KL, Hedberg K, Cieslak PR, Scallan E, Marcus R, et al. Risk factors for sporadic shigellosis, FoodNet 2005. Foodborne Pathog Dis. 2010 Jul;7(7):741–7.
- Kendall ME, Crim S, Fullerton K, Han PV, Cronquist AB, Shiferaw B, et al. Travel-associated enteric infections diagnosed after return to the United States, Foodborne Diseases Active Surveillance Network (FoodNet), 2004–2009. Clin Infect Dis. 2012 Jun;54 Suppl 5:S480–7.
- Tajbakhsh M, Garcia Migura L, Rahbar M, Svendsen CA, Mohammadzadeh M, Zali MR, et al. Antimicrobial-resistant Shigella infections from Iran: an overlooked problem? J Antimicrob Chemother. 2012 May;67(5):1128–33.
- von Seidlein L, Kim DR, Ali M, Lee H, Wang X, Thiem VD, et al. A multicentre study of Shigella diarrhoea in six Asian countries: disease burden, clinical manifestations, and microbiology. PLoS Med. 2006 Sep;3(9):e353.
- Zhang W, Luo Y, Li J, Lin L, Ma Y, Hu C, et al. Wide dissemination of multidrug-resistant Shigella isolates in China. J Antimicrob Chemother. 2011 Nov;66(11):2527–35.
- Centers for Disease Control and Prevention
1600 Clifton Rd
Atlanta, GA 30333
TTY: (888) 232-6348
- Contact CDC-INFO
- Travel Notices
- Find a Clinic
- Disease Directory
- Information Centers
- For Travelers
- Common Travel Health Topics
- Adopting a Child from Another Country
- Adventure Travel
- Bug Bites
- Business Travel
- Counterfeit Drugs
- Cruise Ship Travel
- Cold Climates
- Deep Vein Thrombosis
- Fish Poisoning in Travelers
- Food and Water
- Health Care Abroad
- High Altitudes
- Hot Climates
- Humanitarian Aid Workers
- Jet Lag
- Last-Minute Travel
- Long-Term Travel
- Mass Gatherings
- Medical Tourism
- Mental Health
- Motion Sickness
- Natural Disasters
- Pregnant Travelers
- Road Safety
- Senior Citizens
- Sex Tourism
- Sick After Travel
- Study Abroad
- Sun Exposure
- Swimming and Diving
- Travelers' Diarrhea
- Travelers with Chronic Illnesses
- Travelers with Weakened Immune Systems
- Traveling with a Disability
- Traveling with Your Pet
- Visiting Friends or Relatives
- Water Disinfection
- Infographics for Travelers
- 2014 World Cup in Brazil
- MERS Health Advisory poster
- Food and Water: What's Safer
- Health Advisory: MERS Pictograms
- Risky vs. Safer
- Food and Water: What to Know
- Website Guide
- Going to the American Tropics?
- Recently in the American Tropics?
- Ebola Outbreak - Recently in West Africa?
- Ebola Outbreak - Going to West Africa?
- Advice for Colleges, Universities, and Students about Ebola in West Africa
- Traveler Survival Guide
- CDC-TV Videos
- Common Travel Health Topics
- For Clinicians
- Travel Industry
- For Travelers
- Yellow Book
- Mobile Apps
- RSS Feeds
Before you travel make sure you speak with your doctor.