Hugh M. Mainzer

A Waterborne Outbreak of Norwalk-Like Virus among Snowmobilers—Wyoming, 2001

In February 2001, episodes of acute gastroenteritis were reported to the Wyoming Department of Health from persons who had recently vacationed at a snowmobile lodge in Wyoming. A retrospective cohort study found a significant association between water consumption and illness, and testing identified Norwalk-like virus (NLV) in 8 of 13 stool samples and 1 well. Nucleotide sequences from the positive well-water specimen and 6 of the positive stool samples were identical. This multistrain NLV outbreak investigation illustrates the importance of NLV as a cause of waterborne illness and should encourage monitoring for NLVs in drinking water.

Frequency and causes of vaccine wastage

UNLABELLED Assessing the frequency of vaccine wastage and the relative magnitude of its various causes may help to target efforts to reduce these losses and to husband funds for increasingly expensive vaccines. METHODS As a preliminary overview of wastage in the United States, 64 public-sector state and local health department immunization programs were polled in 1998 and 1999 for wastage recording practices. Actual wastage data were collected from a non-random subset of five states. Data on returns of wasted vaccine to manufacturers were analyzed from routine national biologics surveillance and from an ad-hoc survey. Excise tax credit requests for such returns between 1994 and 1999 were reviewed. RESULTS Rates of wastage among the five states ranged from about 1 to 5% in 1998, with an overall rate of 2.6% among 57 immunization programs in 1999. Categories of wastage used by the health departments varied widely, with overlapping classifications. The major causes appeared to be refrigeration (cold chain) lapses, followed by expiration. Overall rates of vaccine returns varied up to 8% by manufacturer, and from 1 to 50% by vaccine type, with higher return rates generally found for lesser-used vaccines. CONCLUSIONS If these wastage estimates of 1-5% applied nationally, in 1998 there would have been approximately US dollars 6-31 million worth of unused vaccine in the public sector alone. The two most common forms of wastage reveal the potential value of developing vaccines with improved heat stability and longer shelf lives. We propose six main classifications of vaccine wastage for use in routine monitoring and reporting.

Passenger Behaviors During Norovirus Outbreaks on Cruise Ships

BACKGROUND Norovirus causes a majority of outbreaks of gastrointestinal (GI) illness on cruise ships calling on the United States. Control measures include patient isolation, hand washing, and facility closure. Little is known about the behaviors and practices of people who have become ill with norovirus GI illness compared to those who remained well during an outbreak. METHODS Passenger surveys were distributed during three cruise ship outbreaks caused by norovirus. Surveys inquired about illness symptoms, ill contacts, illness reporting status, hand sanitation beliefs and practices, and availability of public hand sanitizer. A case was a passenger reporting three or more episodes of loose stool in a 24-hour period, three or more episodes of vomiting in a 24-hour period, or one or more episodes each of loose stool and vomiting in a 24-hour period. Controls reported that they were not ill during the cruise. RESULTS In total, 1,323 responses were compared. All ships had passengers who were ill prior to embarkation. Most cases delayed or did not report their illness to the ships infirmary because they did not believe it was serious (43%-70% of responses). Cases were less likely to believe that isolation was effective in preventing disease spread [Mann-Whitney-Wilcoxon (MWW) p value <0.0001]. Cases were less likely to believe that hand washing or hand sanitizer are effective means of preventing disease spread (MWW p values 0.002 and 0.04, respectively), wash their hands after restroom use (MWW p value 0.02), or believe that hand sanitizer was available for public use prior to/after knowing about an outbreak (MWW p values 0.002 and 0.03, respectively). CONCLUSIONS Prevention and control of norovirus GI illness may be improved by routine screening of embarking passengers, education about GI illness and its impact on public health, a focus on improving hand-washing practices, and identification of public hand sanitizer dispensing locations.

Beyond compliance: environmental health problem solving, interagency collaboration, and risk assessment to prevent waterborne disease outbreaks

A systems approach to environmental health problem solving was used to investigate two waterborne norovirus outbreaks in Wyoming and can serve in the development of improved prevention strategies. An interagency collaboration to prevent waterborne disease involving local, state, and federal partners was designed to coordinate response to outbreak investigations. Improved risk assessment and reporting procedures were also integrated to ensure better availability of necessary data. Public health entities should implement sustainable intersectoral interventions to prevent waterborne disease that not only improve regulatory compliance but also have a positive impact on community health outcomes. Collaborative preventive health and water system protection activities should receive priority attention for implementation in state and local jurisdictions.