0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
From the Centers for Disease Control and Prevention |

Norovirus Outbreak Among Evacuees From Hurricane Katrina—Houston, Texas, September 2005 FREE

JAMA. 2005;294(22):2834-2837. doi:10.1001/jama.294.22.2834.
Text Size: A A A
Published online

MMWR. 2005;54:1016-1018

1 figure omitted

During the week after Hurricane Katrina struck the Gulf Coast on August 29, 2005, an estimated 240,000 persons, mostly from Louisiana, evacuated to Houston, Texas. On August 31, an estimated 24,000 evacuees were sheltered temporarily at facilities in Reliant Park, a sports and convention complex that includes Reliant Astrodome, Reliant Center, and Reliant Arena. All evacuees to these three facilities were provided with cots, bedding, food, water, and access to lavatories and showers. A medical facility was set up initially to provide emergency care to evacuees and subsequently to serve as a comprehensive outpatient clinic staffed largely by personnel from the Harris County Hospital District (HCHD), Baylor College of Medicine (BCM), and Texas Children’s Hospital (TCH). On September 2, 2005, physicians and staff from Harris County Public Health and Environmental Services (HCPHES) noted a substantial number of adults and children with symptoms of acute gastroenteritis (defined as diarrhea and/or vomiting) at the medical clinic in Reliant Park. In collaboration with HCPHES, CDC and medical personnel of HCHD, BCM, and TCH conducted enhanced surveillance to improve identification of acute gastroenteritis, investigate the apparent outbreak, identify the infectious agent, and implement measures for its control. This report summarizes the preliminary epidemiologic data from this investigation and underscores the challenges to managing a large and rapidly spreading outbreak of norovirus in crowded evacuee settings.

A simple checklist of symptoms was used by HCPHES to collect data on a triage intake form. Data were used as an index of medical problems and care delivered. This information was gathered and entered into a centralized database nightly by HCPHES staff members, and results were distributed to the surveillance team each morning.

During September 2-12, 2005, approximately 6,500 of the estimated 24,000 evacuees visited the Reliant Park medical clinic, and 1,169 (18%) persons reported symptoms of acute gastroenteritis. Three fourths of the patients with acute gastroenteritis symptoms were adults (aged ≥18 years) residing in the three facilities housing evacuees at Reliant Park or in smaller shelters and hotels in Houston. The number of acute gastroenteritis cases peaked on September 5, when 211 persons reported acute gastroenteritis symptoms, and cases declined slowly thereafter. A total of 511 (44%) patients reporting acute gastroenteritis symptoms had diarrhea alone, 342 (29%) reported vomiting, and 316 (27%) reported both diarrhea and vomiting. During September 2-12, approximately 14% of adult visits to the medical clinic and 28% of pediatric visits were for acute gastroenteritis; on peak days, these figures reached 21% and 40%, respectively (other common reasons for visits were chronic diseases and medication refills). In addition, medical personnel, police officers, and volunteers who had direct contact with patients reported acute gastroenteritis symptoms, suggesting substantial secondary spread, presumably by person-to-person contact or fomite transmission. The number of hospitalizations was unknown; no deaths were reported.

To determine the etiologic agent, stool samples (i.e., either rectal swabs or bulk stools) were sent to one of several laboratories of HCHD, BCM, and TCH for diagnosis of bacterial, parasitic, and viral enteropathogens. In stool samples from 44 patients tested by reverse transcription-polymerase chain reaction, norovirus was confirmed in 22 (50%) specimens; no other enteropathogen was identified. Sequencing to determine viral strains is being conducted but is not yet complete.

At the onset of the outbreak, health authorities implemented extensive infection-control measures. Patients with acute gastroenteritis who were dehydrated were rehydrated in a separate observation area reserved for patients with suspected infectious illness and then transferred to an isolation area for at least 48 hours after vomiting and diarrhea had ended. In addition, alcohol-based gel hand sanitizers were distributed throughout the facilities and near lavatories, and a bank of portable sinks was installed inside the medical clinic. Medical staff, disaster relief personnel, volunteers, and evacuees were all alerted to the heightened need for using proper hand-washing techniques through medical staff meetings, posters, banners, and newsletters distributed to all evacuees. Despite these timely interventions, the outbreak continued for more than 1 week but declined before the evacuees vacated Reliant Park in late September.

Reported by:

H Palacio, MD, U Shah, MD, C Kilborn, MPH, D Martinez, MPH, V Page, MPH, Harris County Public Health and Environmental Svcs; T Gavagan, MD, K Mattox, MD, H DuPont, MD, MK Estes, PhD, R Feigin, MD, RL Atmar, MD, FH Neill, J Versalovic, MD, PhD, C Stager, PhD, D Musher, MD, Texas Children’s Hospital, Baylor College of Medicine, and Harris County Hospital District, Houston, Texas. RI Glass, MD, PhD, Div of Viral and Rickettsial Disease, National Center for Infectious Diseases; M Faul, PhD, Div of Injury and Disability Outcomes and Programs, National Center for Injury Prevention and Control; M Davies, MD, North Carolina Dept of Health and Human Svcs; M Cortese, MD, Div of Epidemiology and Surveillance, National Immunization Program; E Lau, MD, EIS Officer, CDC.

CDC Editorial Note:

The epidemiologic and laboratory findings in this report suggest that an outbreak of norovirus gastroenteritis might have affected approximately 1,000 evacuees and relief workers in three facilities at Reliant Park and in other Houston facilities that housed evacuees, including a convention center, smaller shelters, and hotels. The rapidly changing population of evacuees treated at the medical clinic complicated efforts to monitor the magnitude of the outbreak or the extent of disease among evacuees in Reliant Park. Nonetheless, on some days, nearly 21% of adults and 40% of children visiting the Reliant clinic had acute gastroenteritis, confirming the importance of this problem.

Conditions that might have facilitated virus transmission included crowding, insufficient sanitation in lavatories, lack of an adequate number of hand-washing facilities, and delays in cleaning and decontaminating soiled areas and bedding. In addition, initial isolation procedures were difficult to maintain over time because family members already traumatized by displacement, grief, and personal loss were separated from each other because of illness.

Noroviruses are the most common cause of outbreaks of acute gastroenteritis in the United States. Outbreaks not associated with contaminated food or water but spread through person-to-person contact or from fomites tend to occur in crowded settings, such as cruise ships, camps, shelters, and hospital wards.14 Persons infected with norovirus have an acute onset of vomiting and/or nonbloody diarrhea lasting 12-60 hours, with an incubation period of 24-48 hours.5 Certain persons do not become ill when infected, which might be associated with a genetic predisposition to infection conferred by blood group antigens.6 Once an outbreak begins, norovirus is highly contagious and easily transmitted via multiple routes because of its low infectious dose (i.e., <100 viral particles), its ability to persist in the environment, and its resistance to inactivation by multiple cleaning agents.5,7 Furthermore, diagnosis of norovirus through laboratory testing is not widely available, making confirmation of norovirus as the etiologic agent in these types of outbreaks difficult.

Although the challenges to preventing and managing norovirus outbreaks in a disaster relief situation are considerable, certain lessons have been learned from this and other norovirus outbreaks. Early surveillance and identification of outbreaks of acute gastroenteritis with rapid detection of the causative agent are essential to implement timely, focused, and effective interventions. In particular, vigilance to hand-washing techniques; accessibility to soap and water within medical facilities, eating and food-preparation areas, lavatories, and showers; and containment and disinfection of soiled areas and bedding can all help decrease the spread of norovirus. These needs warrant special attention in planning and managing a disaster relief facility.8,9 When feasible, isolation of patients who are actively vomiting or continue to have diarrhea can be instituted, but care should be taken not to further distress traumatized evacuees.

Norovirus should be suspected when outbreaks of acute gastroenteritis occur in a crowded setting, on the basis of its epidemiologic features (i.e., rapid spread and secondary transmission) and clinical presentation (e.g., high prevalence of vomiting). Persons with norovirus gastroenteritis should be treated promptly with rehydration, and measures to prevent secondary transmission (e.g., promoting proper hand-washing techniques and cleaning and disinfecting soiled surfaces) should be taken immediately; however, these measures give no absolute assurance against further spread of norovirus.5,10 The outbreak described in this report was identified early and managed aggressively. However, rapid, sensitive laboratory assays are still needed to detect norovirus and to provide a better understanding of the most effective intervention strategies in crowded evacuee environments.

REFERENCES
CDC.  Norovirus activity—United States, 2002.  MMWR. 2003;52:41-45
Lopman BA, Reacher MH, Vipond IB, Sarangi J, Brown DW. Clinical manifestation of norovirus gastroenteritis in health care settings.  Clin Infect Dis. 2004;39:318-324
PubMed   |  Link to Article
CDC.  Outbreaks of gastroenteritis associated with noroviruses on cruise ships—United States, 2002.  MMWR. 2002;51:1112-1115
CDC.  Outbreak of acute gastroenteritis associated with Norwalk-like viruses among British military personnel—Afghanistan, May 2002.  MMWR. 2002;51:477-479
CDC.  “Norwalk-like viruses”: public health consequences and outbreak management.  MMWR. 2001;50:(No. RR-9)  1-17
Hutson AM, Atmar RL, Graham DY, Estes MK. Norwalk virus infection and disease is associated with ABO histo-blood group type.  J Infect Dis. 2002;185:1335-1337
PubMed   |  Link to Article
Becker KM, Moe CL, Southwick KL, MacCormack JN. Transmission of Norwalk virus during football game.  N Engl J Med. 2000;343:1223-1227
PubMed   |  Link to Article
CDC.  Guidelines for environmental infection control in health-care facilities: recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC).  MMWR. 2003;52:(No. RR-10)  1-42
CDC.  Guideline for hand hygiene in health-care settings: recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force.  MMWR. 2002;51:(No. RR-16)  1-45
CDC.  Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy.  MMWR. 2003;52:(No. RR-16)  1-16

Figures

Tables

References

CDC.  Norovirus activity—United States, 2002.  MMWR. 2003;52:41-45
Lopman BA, Reacher MH, Vipond IB, Sarangi J, Brown DW. Clinical manifestation of norovirus gastroenteritis in health care settings.  Clin Infect Dis. 2004;39:318-324
PubMed   |  Link to Article
CDC.  Outbreaks of gastroenteritis associated with noroviruses on cruise ships—United States, 2002.  MMWR. 2002;51:1112-1115
CDC.  Outbreak of acute gastroenteritis associated with Norwalk-like viruses among British military personnel—Afghanistan, May 2002.  MMWR. 2002;51:477-479
CDC.  “Norwalk-like viruses”: public health consequences and outbreak management.  MMWR. 2001;50:(No. RR-9)  1-17
Hutson AM, Atmar RL, Graham DY, Estes MK. Norwalk virus infection and disease is associated with ABO histo-blood group type.  J Infect Dis. 2002;185:1335-1337
PubMed   |  Link to Article
Becker KM, Moe CL, Southwick KL, MacCormack JN. Transmission of Norwalk virus during football game.  N Engl J Med. 2000;343:1223-1227
PubMed   |  Link to Article
CDC.  Guidelines for environmental infection control in health-care facilities: recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC).  MMWR. 2003;52:(No. RR-10)  1-42
CDC.  Guideline for hand hygiene in health-care settings: recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force.  MMWR. 2002;51:(No. RR-16)  1-45
CDC.  Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy.  MMWR. 2003;52:(No. RR-16)  1-16
CME
Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Collections
PubMed Articles