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Health advisory: Shigella Outbreak Associated with Homeless Encampments in San Jose

June 14, 2024

As of June 14, 2024, three confirmed and 19 suspected shigellosis cases have been identified among individuals experiencing homelessness in Santa Clara County since June 3rd. Based on the field investigation conducted to date there is concern for additional cases among individuals in multiple homeless encampments that may not have sought care at a healthcare facility. Two of the three confirmed cases were hospitalized and two of the three isolates have been identified as Shigella sonneii.

Shigellosis is an acute enteric infection caused by several species of Shigella bacteria. Most Shigella infections are self-limited; however, antimicrobial treatment may be indicated to prevent complications or shorten the duration of illness. Shigella bacteria are transmitted by the fecal-oral route directly through person-to-person contact including sexual contact and indirectly through contaminated food, water, and other routes. Shigella is highly contagious; a very small inoculum (10 to 200 organisms) is sufficient to cause infection.

Healthcare professionals are urged to be vigilant for possible cases of Shigella infection, particularly among persons experiencing homelessness or conducting activity in or near encampments, and to obtain stool testing for identification of common enteric pathogens. Due to recent cases of shigellemia in the Bay Area, clinicians are also advised to have a low threshold for obtaining blood cultures (in addition to stool testing) for suspected cases with compatible symptoms. Per Title 17 section 2505 subsection (m)(2), laboratories must attempt to obtain cultures if culture independent testing (CIDT) was utilized for initial diagnosis and must submit all Shigella specimens or isolates to the County of Santa Clara Public Health Laboratory for further testing as soon as available. Clinicians should request susceptibility testing of any positive cultures.

Actions Requested of Healthcare Providers

  1. SUSPECT shigellosis in patients experiencing homelessness, or conducting activity in or near encampments, with signs and symptoms of acute enteric illness.
  2. TEST patients experiencing homelessness with compatible signs and symptoms for common enteric pathogens (e.g. Shigella, Salmonella, E.coli, etc.) in the stool and have a low threshold to obtain blood cultures. When a patient with Shigella is identified, especially if culture independent testing is utilized, request reflex cultures and susceptibility testing.
  3. TREAT appropriately and follow-up on susceptibility testing and ensure antimicrobial therapy remains effective for the duration of treatment. There are limited susceptibility data thus far in this outbreak to guide definitive empiric treatment recommendations. Given presence of resistance to TMP-SMX and third generation cephalosporins among the two confirmed cases, Ciprofloxacin for uncomplicated cases and broad-spectrum antibiotics (such as piperacillin-tazobactam or a carbapenem) for severe disease/critical illness are reasonable options. These preliminary recommendations may be updated as additional susceptibility data from outbreak-related cases becomes available.
  4. REPORT suspected and confirmed cases of Shigella infection to Santa Clara County Public Health Department by calling (408) 885-4214, ext 3 or by completing a CMR and submitting the completed form via secure fax to (408) 885-3709. Please include full demographics and note on the CMR if the patient is known to be experiencing homelessness.
  5. SEND isolates to the Public Health Laboratory for additional testing and analysis to aid in the outbreak investigation. For samples being sent to SCC PHL, please submit a laboratory specimen submission form.
  6. COUNSEL patients with suspected or confirmed shigellosis about measures they can take to keep others healthy. Patients taking antibiotics should continue to follow prevention measures. All patients with suspected or confirmed shigellosis should:
  • Wash hands often with soap and water for at least 20 seconds, including at key times such as after using the toilet, before and after changing diapers, cleaning up after someone who is sick, and before preparing or eating food.
  • During diarrhea and for 2 weeks after it ends,
    • Do not prepare food for others, if possible.
    • Stay out of recreational water, including swimming pools, hot tubs, water playgrounds, oceans, lakes, and rivers.
    • Wait to have sex (vaginal, anal, and oral). When you start having sex again, wash your body and hands before and after sex, including in and around the anus and genitals. During oral sex or oral-anal sex, use barriers, such as condoms, natural rubber latex sheets, dental dams, or cut-open non-lubricated condoms between your rectum and your partner's mouth. During anal or vaginal sex, use condoms. Wash hands after handling used condoms or other barriers. Wash sex toys before and after use with soap and water.
  • Stay home from childcare/school or from non-urgent healthcare, food service, or childcare jobs while sick or until the health department says it’s safe to return.

Resources: 

 

***Santa Clara County Public Health Department is moving to an email system to send out health alerts, advisories, and updates. These notifications provide official guidance from the Santa Clara County Health Officer to inform clinicians about important public health issues, such as communicable disease outbreaks. To receive these emails, please sign up at http://eepurl.com/dqocab. Note: if you are part of a hospital or health system in Santa Clara County, you might already receive these emails from your administrator.***

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