Shigella

Division of Community and Public Health Section: 4.0 Diseases and Conditions

Revised 3/2011

Subsection: Shigellosis

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Shigellosis Table of Contents Shigellosis Shigellosis Facts (CDC) Sample Letter to Parents (Child Care Center) Disease Case Report (CD-1) Record of Investigation of Enteric Illness Form (CD-2C)

(Fillable)

Missouri Outbreak Surveillance Report (CD-51)

Missouri Department of Health and Senior Services Communicable Disease Investigation Reference Manual


Revised 3/2011


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Overview(1,2,3) Shigellosis is an infectious disease caused by a group of bacteria called Shigella. There are several different kinds of Shigella bacteria (Shigella sonnei,,Shigella flexneri, Shigella boydii, and Shigella dysenteriae): Shigella sonnei, also known as "Group D" Shigella, accounts for over two-thirds of shigellosis in the United States. Shigella sonnei is also the most common serotype in Missouri. Most Shigella infections are the result of the bacterium passing from stools usually via inadequately washed hands of one person to the mouth of another person. Shigella bacteria are present in the diarrheal stools of infected persons and generally can be excreted in feces for 1 to 4 weeks, in persons without antimicrobial therapy. (Transmission can occur as long as the bacteria are present in the feces.) The infectious dose for shigellosis is quite small (10-200 organisms). Transmission occurs when basic hygiene and handwashing habits are inadequate and can happen during certain types of sexual activity. Transmission is particularly likely to occur among toddlers who are not fully toilet-trained. Family members, playmates, and care givers of such children are at high risk of becoming infected. Shigella infections may also be acquired from eating contaminated food, or drinking contaminated water. Most persons who are infected with Shigella develop diarrhea (watery or loose stools), fever, and stomach cramps starting a day or two after they are exposed to the bacteria. The diarrhea can be bloody. Although bacillary dysentery caused by Shigella dysenteriae can be a very serious disease, with case-fatality rates as high as 20% among hospitalized cases, Shigella infections are usually a self-limiting diarrheal illness that resolves without need for antibiotic treatment. Antimicrobial therapy however, is effective in shortening the duration of diarrhea and eradicating organisms from feces. Treatment is recommended for patients with severe disease, dysentery, or underlying immunosuppressive conditions; in these patients, empiric therapy should be provided while awaiting culture and susceptibility results. In mild disease, the primary indication for treatment is to prevent spread of the organism. Antimicrobial susceptibility testing of clinical isolates is indicated, because resistance to antimicrobial agents is common and susceptibility data can guide appropriate therapy. The incubation period for shigellosis is usually 1–3 days, but may range from 12 to 96 hours; however S. dysenteriae 1, may incubate for up to a week. Shigellosis is diagnosed by isolation of the organism from bacterial culture of stool specimens. Treatment should include fluid and electrolyte replacement to prevent dehydration. The spread of shigellosis can be difficult to control, prompt reporting of cases by health care providers to public health agencies, and the implementation of prompt control measures is essential. Strict attention to hand hygiene is essential to limit spread. Other important control measures include the exclusion of persons with known Shigella infections and ill contacts from food handling, and the care of children or patients until appropriately screened. Infected persons should refrain from recreational water venues (e.g., swimming pools, water parks) for 1 week after symptoms resolve.



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For a more complete description of Shigellosis, refer to: • Control of Communicable Diseases Manual (CCDM), American Public Health Association, 19th Edition, 2008 • American Academy of Pediatrics. Red Book: 2009 Report of the Committee on Infectious Diseases. 28th ed. 2009

Case Definition(4) Clinical description An illness of variable severity characterized by diarrhea, fever, nausea, cramps, and tenesmus (ineffectual and painful straining at stool). Asymptomatic infections may occur. Laboratory Criteria for Diagnosis: Isolation of Shigella from a clinical specimen. Case Classification: Confirmed: a case that meets laboratory criteria for diagnosis. When available, O antigen serotype characterization should be reported. Probable: a clinically compatible case that is epidemiologically linked to a confirmed case. Note: Both asymptomatic infections and infections at sites other than the gastrointestinal tract, if laboratory confirmed, are considered confirmed cases that should be reported. Comment: Shigella dysenteriae, while rare in Missouri, is a serious illness. If a case of Shigella dysenteriae, is reported, contact the District Communicable Disease Coordinator immediately.

Information Needed for Investigation

Verify the diagnosis. Obtain demographic, clinical and laboratory information on the case from the attending physician, hospital, and/or laboratory. Obtain the information necessary to complete the “Disease Case Report” (CD-1), and the “Record of Investigation of Enteric Illness” (CD-2C) revised 10-09 from the patient. Establish the extent of illness. Ask about illnesses among household, sexual (heterosexual and homosexual), childcare, hospital or long term care, and other intimate contacts. Ask if the case provided child or patient care, or prepared food for anyone outside the household. Ask if the case lived or spent significant time in another household. Review surveillance data to determine whether there has been a recent increase in shigellosis in the same geographic area or institution. When cases are related by time, place, or person, efforts should be made to identify the source. When investigating a suspected outbreak of gastrointestinal illness of unknown etiology, see the “Outbreaks of Acute Gastroenteritis” Section. Missouri Department of Health and Senior Services Communicable Disease Investigation Reference Manual


Revised 3/2011


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Identify the most likely source of infection, in order to prevent other cases.  Does the case or a member of the case's household attend a childcare center or nursery school?  Does the case or a member of the case's household work as a food handler or healthcare provider?  Identify symptomatic household and other close contacts and obtain stool specimens.  Has the case traveled to an area where shigellosis is known to be endemic or where there is a known outbreak occurring?  Have there been other cases linked by time, place or person?  Does the case engage in sexual or other practices that would put him/her or others at increased risk?

Notification

Immediately contact the District Communicable Disease Coordinator, or the Senior Epidemiology Specialist for the District or the DHSS Situation Room (DSR) at 800-392-0272 (24/7) if an outbreak* of shigellosis is suspected. If the case is in a high-risk setting or job such as food handling, childcare or health care contact the District Communicable Disease Coordinator and the appropriate Bureau(s) as listed below.  Contact the Bureau of Environmental Health Services (BEHS) at (573) 751-6111 and the Section for Child Care Regulation (573) 751-2450 if a case is associated with a child care facility.  Contact BEHS at (573) 751-6111 when a case is a foodhandler.  Contact the Section for Long Term Care Regulation (573) 526-8505, if a case is associated with a long-term care facility.  Contact the Bureau of Health Services Regulation (573) 751-6303, if a case is associated with a hospital or hospital-based long-term care facility. *Outbreak is defined as the occurrence in a community or region, illness(es) similar in nature, clearly in excess of normal expectancy and derived from a common or a propagated source.

Control Measures General control measures to prevent additional cases should include:  Strict attention to hand hygiene is essential to lim it spread. Wash hands with soap caref ully and f requently, especially afte r go ing to th e b athroom, after changing di apers, and before preparing food, beverages, or caring for childr en or patients. Supe rvise handwashing of toddlers and small children after they use the toilet.  Dispose of soiled diapers properly and wash/rinse/sanitize diaper changing areas after using them.  Keep children with diarrhea out of child care settings.  Do not prepare food for others while ill with diarrhea.  Shigellosis cases and ill contacts should be excluded from foodhandling, the care of children or patients, and other occupations that pose significant risk of transmission until Missouri Department of Health and Senior Services Communicable Disease Investigation Reference Manual

Division of Community and Public Health

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Section: 4.0 Diseases and Conditions

Revised 3/2011


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diarrhea ceases and appropriate medical documentation is provided showing the person is free of Shigella infection based on test results. Avoid swallowing water from ponds, lakes, or untreated pools. Infected persons should refrain from recreational water venues (e.g. swimming pools, water parks) for 1 week after symptoms resolve.(2) Breastfeeding provides some protection for infants. Daycare centers should not provide shared water-play areas. Provide prompt c ase r eports to publi c hea lth authorities by health care provi ders (e.g. hospital infection control personnel and public health department) is essential.

Control Measures High-risk settings Foodhandlers:(1,2,6) If a food employee is diagnosed with shigellosis and is symptomatic:  Exclude the food employee from the food establishment. If a food employee is an ill contact of a shigellosis patient:  Exclude the food employee from the food establishment. If a food employee is diagnosed or suspected of having shigellosis and is asymptomatic:  Exclude the food employee who works in a food establishment serving highly susceptible populations.**  Restrict*** the food employee who works in a food establishment not serving highly susceptible populations. A restricted employee must be asymptomatic for at least 24 hours before returning to the food establishment. The excluded or restricted asymptomatic food employee may be reinstated: 1. With written medical documentation showing the food employee is free of Shigella infection based on test results showing 2 consecutive negative stool cultures that are taken at least 24 hours after diarrhea ceases, not earlier than 48 hours after discontinuation of antibiotics, and at least 24 hours apart; or 2. The excluded or restricted food employee may be reinstated after symptoms of vomiting or diarrhea resolve, and more than 7 calendar days have passed since the food employee became Dsymptomatic; or 3. The food employee who was excluded or restricted and did not develop symptoms, and more than 7 calendar days have passed since the food employee was diagnosed. **Highly susceptible population means persons who are more likely that other people in the general population to experience foodborne disease because they are: 1. Immunocompromised; preschool age children, or older adults; and 2. Obtaining the food at a facility that provides services such as custodial care, health care, or assisted living, such as child or adult care center, kidney dialysis center, hospital or nursing home, or nutritional or socialization services such as a senior center.



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***Restrict means to limit the activities of a food employee so that there is no risk of transmitting a disease that is transmissible through food and the food employee does not work with exposed food, clean equipment, utensils, linens, or unwrapped single-service or single-use articles.

Appropriate antimicrobial therapy is effective in shortening the duration of diarrhea and eradicating organisms from feces. Child Care: Due to the potential for rapid spread in the child care setting, special measures are recommended when shigellosis is diagnosed in an attendee or employee of a child care facility. Shigella outbreaks involving groups of young children, especially those who are not yet toilet trained, can be difficult to control. Increased surveillance within the child care facility to identify others with diarrheal illness is essential.  Emphasize handwashing. Because good hand hygiene is the best preventive measure, supervised handwashing after visiting the bathroom and before eating is essential for all children. Waterless hand sanitizers may also be helpful as an adjunct to washing hands with soap.  Food employees handling food in child care settings should follow the criteria above for food employees serving a highly susceptible population.**  Staff who prepares food should not change diapers, or assist children in using the toilet.  Surfaces and objects should be decontaminated regularly; daily during an outbreak of shigellosis.  Access to shared water-play areas and contaminated diapers should be eliminated.(2)  Centers should avoid new admissions when Shigella infections have been identified and transmission has been epidemiologically linked to the center.(2)  Children and child care staff with diarrhea should be excluded from day care until they are well. Shigellosis is transmitted easily and can be severe, so all symptomatic persons (employees and children) should be excluded from the childcare setting in which Shigella infection has been identified, until diarrhea has ceased for 24 hours; and one (1) stool culture is free of Shigella spp.; specimens should not be obtained earlier than 48 hours after discontinuation of antibiotics.(7) Antimicrobial therapy is effective in shortening the duration of diarrhea and eradicating organisms from feces.  Infected persons should refrain f rom recreatio nal water venues (e.g. sw imming pools, water parks) for 1 week after symptoms resolve.(2) Contact the Section for Child Care Regulation for an Environmental Public Health Specialist to perform an assessment of the childcare facility. The inspection should include emphasis on the items listed in “Day Care Establishment Inspection Related to Enteric Infection” (CD-8).



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To prevent the spread of infection, efforts should be made to avoid the transfer of children to other childcare centers. Closure of affected childcare centers may lead to placement of infected children in other centers (with subsequent transmission in those centers) and is counterproductive. If several persons are infected, a cohort system can be considered until one negative stool culture shows the person is free of Shigella infection and can be returned to normal care. Health Care Providers: Infected health care workers and ill contacts should be excluded from patient care, and other occupations that pose significant risk of transmission, until diarrhea ceases for 24 hours and obtain 2 consecutive negative stool cultures; not earlier that 48 hours after discontinuation of antibiotics, and at least 24 hours apart. In residential institutions, ill people and newly admitted patients should be housed in separate areas. Schools and Preschools: In the school setting, hand hygiene is the most important control measure. Teachers and students with any diarrheal illness should be excluded from the school until 24 hours after their diarrhea has ceased. If an outbreak in a school cannot be controlled with improved hygiene and exclusion of those with diarrhea, then additional intervention may be necessary.

Guidelines for Screening and Management of Food Services and Other High Risk Workers During Outbreaks See page 27 of 67.

(http://www.dhss.mo.gov/living/healthcondiseases/communicable/communicabledisease/cdmanual/pdf/CDsec30.pdf )

Laboratory Procedures

Specimens: Collect specimens in Cary-Blair media using the Enteric Specimen Collection Kit supplied by the State Public Health Laboratory (SPHL). Specimens should be shipped refrigerated. Identification of Shigella requires the collection of a fecal specimen as early in the course of the illness as possible and before antibiotic therapy begins. Blood specimens and rectal swab specimens are not acceptable specimens for analysis by the SPHL. Testing: The search for unrecognized mild cases (without diarrhea) and convalescent carriers among contacts may be unproductive, and seldom contributes to the control of an outbreak. Cultures of contacts should generally be confined to food employees, attendants and children in hospitals, child care and other situations where the spread of infection is likely.(1) Shigella sp. is frequently resistant to antibiotics. Antibiotic sensitivity testing, while not performed by the SPHL, is routinely available through commercial labs and is indicated Missouri Department of Health and Senior Services Communicable Disease Investigation Reference Manual


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because resistance to antimicrobial agents is common and susceptibility data can guide appropriate therapy. (2)

Reporting Requirements

Shigellosis is a reportable disease and shall be reported to the local health authority or to the Missouri Department of Health and Senior Services (DHSS) within one (1) day of first knowledge or suspicion, by telephone, facsimile, or other rapid communication. 1. For confirmed and probable cases, complete a “Disease Case Report” (CD-1), and a “Record of Investigation of Enteric Infection” (CD-2C, rev. 10/09). 2. Entry of the completed CD-1 and CD-2C into WebSurv negates the need for the form(s) to be forwarded to the District Health Office. 3. All outbreaks or suspected outbreaks must be reported as soon as possible (by phone, fax, or e-mail) to the District Communicable Disease Coordinator. This can be accomplished by completing the Missouri Outbreak Surveillance Report (CD-51). 4. Within 90 days from the conclusion of an outbreak, submit the final outbreak report to the District Communicable Disease Coordinator.

References

1. American Public Health Association. (2008). Shigellosis (Bacillary dysentery). In D. Heymann (Ed.), Control of Communicable Diseases Manual (19th ed., pp. 556-560). Washington, DC: American Public Health Association. 2. American Academy of Pediatrics. Shigella Infections. In: Pickering LK, Baker CJ, Kimberlin DW, Long SS, eds. Red Book: 2009 Report of the Committee on Infectious Diseases. 28th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2009: pp. 593-596 3. Churchill Livingstone Elsevier . Shigella Species (Bacillary Dysentery) Dupont HL, In: Mandell GL, Bennett JE, Dolin RD, eds. Mandell, Douglas, and Bennett’s Principles and Practices of Infectious Diseases: Vol. 2. 7th ed; pp. 2905-2910 4. Centers for Disease Control and Prevention. National Notifiable Infectious Conditions, United States 2010. Shigellosis (Shigella spp.) 2005 Case definition. Retrieved September 14, 2010 from: http://www.cdc.gov/ncphi/disss/nndss/phs/infdis2010.htm 5. Centers for Disease Control and Prevention. National Center for Zoonotic, Vector-Borne, and Enteric Diseases. Shigellosis, General information. Retrieved September 14, 2010 from: http://www.cdc.gov/nczved/divisions/dfbmd/diseases/shigellosis/ 6. U.S. Department of Health and Human Services, Public Health Service, Food and Drug Administration, Food Code 2009 7. Turabelidze G, Bowen A, Lin M, Tucker A, Butler C, Fick F, Convalescent cultures for control of shigellosis outbreaks, Pediatr Infect Dis J. 2010 Aug;29(8):728-30 8. Missouri Department of Health and Senior Services. 19 CSR 30-62--Health. Chapter 62-Licensing Rules for Group Day Care Homes and Child Day Care Centers. Retrieved September 14, 2010 from: http://www.sos.mo.gov/adrules/csr/current/19csr/19c30-62.pdf 9. Nelson P. Moyer, Ph.D. (1996, March) The elusive epidemiology of shigellosis. University of Iowa Hygienic Laboratory. Retrieved September 14, 2010 from: http://www.uhl.uiowa.edu/publications/archive/hotline/1996/1996_03/shigellosis.xml Missouri Department of Health and Senior Services Communicable Disease Investigation Reference Manual

Shigella

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