Christine L. Case, Ed.D.
Biology Professor
Skyline College

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Hurricane Katrina Microbiology
 

Oct 18, 2005- Twenty-four cases of hurricane-associated Vibrio vulnificus and V. parahaemolyticus wound infections were reported, with six deaths.

The deaths appear to have been caused by Vibrio vulnificus, a bacterium common in warm Gulf Coast waters that's usually spread by eating contaminated food but that can penetrate open wounds, too (see the figure). The deaths — one a hurricane refugee evacuated to Texas, the other three in Mississippi — were attributed to wound infections, said Tom Skinner, spokesman for the Centers for Disease Control and Prevention, which received the reports from officials in the two states.

V. vulnificus is halophilic and requires 1% NaCl in its growth media. Generally it causes gastroenteritis in only a minority of infections; rather, ingestion leads to a life-threatening invasion of the bloodstream. People with compromised immune systems are at a higher risk. Anyone suffering from liver disease is also at high risk of sepsis, which is fatal about 50% of the time. V. vulnificus frequently causes very dangerous infections of minor skin lesions incurred in coastal sea waters. Rapidly spreading tissue destruction from these infections may require limb amputations, and if sepsis occurs, the fatality rate is about 25%.
 

Dermatologic Conditions
Among hurricane evacuees from the New Orleans area, a cluster of infections with methicillin-resistant Staphylococcus aureus (MRSA) was reported in approximately 30 pediatric and adult patients at an evacuee facility in Dallas, Texas. Three of the MRSA infections were confirmed by culture.

Among rescue workers, CDC received reports of the following two types of skin lesions with infectious etiology: tinea corporis among military personnel from two locations working in the wet environment of early evacuation efforts, and an erythematous, papular, and pustular rash consistent with folliculitis among military personnel working in Mississippi. In addition, the following three rashes subsequently determined to be noninfectious were reported in rescue workers: 1) prickly heat (miliaria crystalline, rubra, and pustulosa); 2) two clusters of nonpruritic erythematous papular, nonfollicular lesions in exposed skin of 97 military rescue workers in Louisiana presumed to have been caused by arthropod (likely mite) bites; and 3) circumferential lesions, appearing as bands of macerated skin at the waist, attributed to excessive chafing.

Diarrheal Disease
CDC received reports of clusters of diarrheal disease among persons in evacuation centers in Louisiana, Mississippi, Tennessee, and Texas. In Louisiana, approximately 20 clusters of diarrheal illness in evacuation centers were reported and investigated. In Memphis, Tennessee, gastrointestinal illness was the most common acute disease complaint among evacuees. Approximately 1,000 cases of diarrhea and vomiting were reported among adult and child evacuees in Mississippi and Texas; tests detected norovirus in stool specimens from patients in Texas. Sporadic nontyphoidal Salmonella, nontoxigenic V. cholerae O1, and other infections were identified. No confirmed cases of Shigella dysentery, typhoid fever, or infection by toxigenic V. cholerae O1 were reported in evacuees from Hurricane Katrina. Three weeks after the initial displacement caused by Katrina, few cases of diarrheal disease were being reported.

Respiratory Disease
Upper respiratory infections and pneumonias were reported among evacuees, including a case of pertussis in an infant aged 2 months who was rescued from a rooftop in New Orleans and evacuated to Tennessee. Appropriate antimicrobial prophylaxis was provided, and contact tracing identified no additional cases.

Control of tuberculosis (TB) among evacuees has consisted both of detecting new cases and providing treatment continuity for previously known cases. A homeless person without a previous diagnosis of TB who was evacuated from New Orleans to Philadelphia was identified by entry screening with symptoms consistent with pulmonary TB. The patient was promptly isolated and began treatment for TB disease; a subsequent culture confirmed TB. At least eight other evacuees initially identified as potentially having TB were subsequently determined to have other conditions (e.g., lung cancer and infection with nontuberculous mycobacteria).

Treatment of TB requires a multidrug regimen for at least 6 months administered under directly observed therapy. A total of 195 persons in the most directly affected regions (eight counties in Alabama, six parishes in Louisiana, and 11 counties in Mississippi) were known by the local public health authorities to be undergoing treatment for TB disease when Hurricane Katrina struck on August 29. Immediately after the hurricane struck, TB program staff sought out known TB patients to check their status and assure that therapy continued. As of September 23, all 27 currently known TB patients who resided in Alabama, all 21 in Mississippi, and 105 (71%) of 147 in Louisiana had been located through a coordinated local, state, and federal public health response. Of the 42 TB patients from Louisiana not yet located, 41 were considered noncontagious at the time the hurricane made landfall on the basis of disease site, treatment duration, or smear status. However, treatment needs to be completed to prevent recurrence of disease and potential for emergence of drug resistance. Intense efforts continue to locate the remaining patients.
  Image from CDC.