Vibrio parahaemolyticus gastroenteritis and international air travel

In-flight transmission of foodborne disease: How can airlines improve?

Food contamination during air travel presents unique risks to those affected. Foodborne pathogens can cause serious illness among all on board, and potentially jeopardize flight safety. These risks are likely to increase with current trends of "densification" and a predicted massive expansion of air travel. While aircraft are being equipped with ever newer designs with a focus on efficiency and comfort, regulations remained largely unmodified in terms of basic hygiene requirements. Strict guidelines for food hygiene exist for on-ground food settings and catering kitchens. There is uncertainty about hygiene standards on board commercial aircraft, and little regulatory oversight of what happens to food in-flight. In two hypothetical scenarios we indicate the potential risks associated with poor food handling practice onboard aircraft, with the ultimate aim of bringing aviation food safety in line with on-ground regulations. Changes in cabin design alongside adequate training in safe food handling have the potential to increase public health protection. We urge a review of existing in-flight hygiene protocols to better direct the development of regulation, prevention, and intervention measures for aviation food safety.

[Prevalence of clinically important species of the genus Vibrio in catered seafood of city and port of Progreso de Castro, Yucatan, Mexico]

INTRODUCTION

Species of the genus Vibrio are invariably gram-negative bacilli, between 2 and 3 µm long and curved in shape, sometimes equipped with a single polar flagellum that allows high mobility. They tolerate well alkaline media and high-salt concentrations in their environment. They do not form spores, are oxidase-positive and facultative anaerobes. The aim of this study was to determine the prevalence of clinically-important species of the genus Vibrio in raw, marinated without heat, partially cooked with heat and completely cooked with heat seafood.

METHODS

This is a study with a quantitative approach. We obtained a list of 38 caterers that specialized in the sale of marine foods of animal origin for human consumption. The number of marine animal foods in those caterers was 790. For homogenization and enrichment of samples and for the isolation and identification of species, we proceeded according to the methodology described in the Bacteriological Analytical Manual. Intervals to estimate a confidence level of 95% were applied.

RESULTS

The prevalence obtained in raw, marinated without heat, partially cooked with heat and completely cooked with heat seafood were 44.30% (276/623), 32.00% (8/25), 30.53% (29/95) and 17.02% (8/47), respectively.

CONCLUSIONS

These results should be taken into consideration when planning to avoid healthcare problems and food-borne diseases in the population that consumes this type of food in the city and port of Progreso de Castro, in Yucatán, Mexico.

Comparison of V. parahaemolyticus isolated from seafoods and cases of gastrointestinal disease in the UK

In this study the prevalence of Vibrio parahaemolyticus in shellfish and estuarine waters from the UK was examined using cultural and nucleic acid hybridisation approaches. Forty-nine isolates derived from environmental sources were characterised using serotyping, PCR, nucleic acid hybridisation and pulsed field gel electrophoresis (PFGE). The serotypic and molecular profiles of these isolates were compared to 20 clinical isolates, including representatives of the pandemic O3:K6 clone. Thirty percent of environmental samples were positive for V. parahaemolyticus. The tdh gene was identified in 12% of samples tested. Environmentally derived tdh+ strains were highly heterogeneous with neither association between isolates from similar origins nor seafood type. Previously uncharacterised clinical strains from UK patients with travel related V. parahaemolyticus associated gastroenteritis, were unrelated to tdh+ or tdh- environmental isolates but 2 were clonally indistinguishable from the pandemic O3:K6 strain responsible for outbreaks in Spain, Korea, Japan and Laos.

Food-poisoning and commercial air travel

With the introduction of budget airlines and greater competitiveness amongst all airlines, air travel has now become an extremely popular form of travel, presenting its own unique set of risks from food poisoning. Foodborne illness associated with air travel is quite uncommon in the modern era. However, when it occurs, it may have serious implications for passengers and when crew are affected, has the potential to threaten safety. Quality, safe, in-flight catering relies on high standards of food preparation and storage; this applies at the airport kitchens (or at subcontractors' facilities), on the aircraft and in the transportation vehicles which carry the food from the ground source to the aircraft. This is especially challenging in certain countries. Several foodborne outbreaks have been recorded by the airline industry as a result of a number of different failures of these systems. These have provided an opportunity to learn from past mistakes and current practice has, therefore, reached such a standard so as to minimise risk of failures of this kind. This review examines: (i) the origin of food safety in modern commercial aviation; (ii) outbreaks which have occurred previously relating to aviation travel; (iii) the microbiological quality of food and water on board commercial aircraft; and (iv) how Hazard Analysis Critical Control Points may be employed to maintain food safety in aviation travel.

Estimation of tuberculosis risk on a commercial airliner

This article estimates the risk of tuberculosis (TB) transmission on a typical commercial airliner using a simple one box model (OBM) and a sequential box model (SBM). We used input data derived from an actual TB exposure on an airliner, and we assumed a hypothetical scenario that a highly infectious TB source case (i.e., 108 infectious quanta per hour) travels as a passenger on an 8.7-hour flight. We estimate an average risk of TB transmission on the order of 1 chance in 1,000 for all passengers using the OBM. Applying the more realistic SBM, we show that the risk and incidence decrease sharply in a stepwise fashion in cabins downstream from the cabin containing the source case assuming some potential for airflow from more contaminated to less contaminated cabins. We further characterized spatial variability in the risk within the cabin by modeling a previously reported TB outbreak in an airplane to demonstrate that the TB cases occur most likely within close proximity of the source TB patient.

Infectious colitis excluding E. coli O157:H7 and C. difficile

Colitic infection caused by a variety of organisms may have an extremely varied presentation, course, and treatment response. Current data have provided great insights into the pathophysiology of these various organisms and their clinical presentation, course, and treatment outcomes. As clinicians develop a better understanding of the colon, its immunologic defense mechanisms, and the virulence factors of such organisms, they will be better able to evaluate these infections as well as newer colonic infections yet unknown. It is important to know if and when to treat such organisms to prevent the dilemma of drug-resistant strains, as seen already in a variety of well-known infections, such as Campylobacter and others. Knowledge of such colonic targets will be more important in an era of ever-growing resistance to and wide use of antibiotic regimens.

Development of the immunomagnetic enrichment method selective for Vibrio parahaemolyticus serotype K and its application to food poisoning study

A method using immunomagnetic separation was developed to isolate the specified K serotype of Vibrio parahaemolyticus from a mixture of a large number of bacteria with other K serotypes. This method was applied to food poisoning studies and could recover the V. parahaemolyticus serotype found in the patient from the incriminated foods.

Market fish hygiene in Kenya

Vibrio parahaemolyticus was isolated from 53 out of 584 samples (9.1%) of market fish. All strains were Kanagawa negative and were distributed as follows: sea fish 5 out of 370 samples (1.4%), shellfish 48 out of 214 samles (22.4%). Other fish spoilage microflora recovered were: Alcaligenes faecalis, Pseudomonas aeruginosa, Proteus vulgaris, Aeromonas spp. and Vibrio alginolyticus. Total aerobic counts and coliform counts per gram for the lake fish ranged from 2.6 X 10(2) to 6.6 X 10(7) and 10 to 1.0 X 10(2), respectively. Those from marine fish ranged from 1.0 X 10(5) to 8.8 X 10(6) and 2.0 X 10(3) to 1.6 X 10(4), respectively. Counts for marine fish gills alone ranged from 1.4 X 10(5) to 3.4 X 10(8) and 7.2 X 10(2) to 1.4 X 10(7), respectively. No high-temperature (44 degrees) coliforms were recovered from either lake or marine samples.

The distribution of Vibrio parahaemolyticus serotypes in Kenyan seafish, shellfish, marine water and sediment

Vibrio parahaemolyticus was recovered from 74 of 912 marine samples screened for the organism. Of 74 isolates of V. parahaemolyticus obtained from marine fish, crustacean shellfish (prawns, lobster, crabs), and molluscan shellfish (oysters), and from water and sediment collected off the coast of Kenya, only 33 were positively identified. The isolates were only from seafish and shellfish. The main serotypes were 0,3:K37; 0,3:K40; 0,8:39; 0,10:23; 0,10:K52; and 0,11:K40. All the serotypes were Kanagawa-negative. The rest of the samples, mainly marine sediment and water, revealed what was described as untypable Vibrios. This is the first report of the organism in this part of the world where no clinical disease is reported.

Vibrio parahaemolyticus and related halophilic Vibrios

Approximately 30 years have elapsed since Dr. Fujino's original discovery that Vibrio parahaemolyticus (then termed Pasteurella parahemolytica) was the cause of "summer diarrhea" in Japan. Since that finding, V. parahaemolyticus has been established as a cause of gastroenteritis in numbers and places approaching global proportions. It has been isolated in marine and estuarine areas almost worldwide and despite its halophilic nature, V. parahaemolyticus has been isolated from saline-free waters. The relationship of this organism to the environment reveals a close association with other marine organisms especially copepods on which the Vibrios depend for survival in winter months and growth in summer months. There is a uniquely provocative disparity between human strains of V. parahaemolyticus which are Kanagawa phenomenon (KP) positive and the environmental strains which to a large extent are KP negative, the significance being that pathogenicity is measured according to the Kanagawa phenomenon (hemolytic activity) reaction. The hemolysin of the pathogenic strains is a thermostable, cardiotoxic protein, which thus far has not been implicated in the mechanism(s) which causes human gastroenteritis. The interest in this organism has been widened in recent years by the finding that similar organisms, V. alginolyticus, lactose positive vibrios and group F vibrios also cause serious disease in humans.

Kanagawa phenomenon and serotypic pattern of Vibrio parahaemolyticus strains isolated from various sources in Calcutta

A total of 135 strains of Vibrio parahaemolyticus isolated during the period 1976-77 from human gastroenteritis cases and various categories of environmental sources, e.g., crustaceans, fish and different water samples (pond, stored, open well and tap water) were tested for their Kanagawa phenomenon and serotypic pattern. Amongst the 80 human isolates tested, 69 strains (86.3%) were Kanagawa phenomenon positive, and 60 strains (75.0%) were serologically typable--the dominant serotype being 05:K15. Of the 25 isolates from various water sources 10(40.0%) were Kanagawa phenomenon positive, and 17(68.0%) were serologically typable and 4 (23.5%) of them belonged to serotype 05:K15. All the 30 strains isolated from crustaceans and fish were Kanagawa phenomenon negative and 22 (73.3%) of them were serologically typable, belonging to heterogeneous serotypes. The results of this study also indicate the possible role of water in the transmission of V. parahaemolyticus infection in Calcutta slums.

Isolation of an enteropathogenic, Kanagawa-positive strain of Vibrio parahaemolyticus from seafood implicated in acute gastroenteritis

A strain of Vibrio parahaemolyticus, serotype O4/K4, that was Kanagawa positive and reactive in the rabbit ileal loop test, was isolated in low numbers from raw oysters implicated in a case of acute gastroenteritis. To our knowledge, this is the first report of the isolation of a Kanagawa-positive strain from suspect food in the United States.

Food hygiene and travel at sea

The incidence of gastroenteritis on a passenger ship is reviewed and discussed in relation to the agents of infection from stool specimens, the bacteriological condition of food samples, and the practice of galley hygiene.

Clinical aspects of outbreak of staphylococcal food poisoning during air travel

An outbreak of staphylococcal food poisoning among 364 charter-flight passengers and crew members is described. Symptoms appeared just before landing, about an hour after a meal containing contaminated ham had been served. 143 passengers were admitted to hospital. 1 patient developed acute anuria and 1 had hemiplegia and aphasia; both recovered. Fever and bloody stools were recorded with unusual frequency.

Staphylococcal food poisoning aboard a commercial aircraft

On Feb. 3, 1975, 196 (57%) of 344 passengers and 1 steward aboard a commercial aircraft contracted a gastrointestinal illness characterised by nausea, vomiting, abdominal cramps, and diarrhoea; 142 passengers and the steward were admitted to hospital. Symptoms developed shortly after a ham and omelette breakfast had been served. An investigation strongly incriminated ham as the vehicle of the outbreak, and the source seems to have been a cook with lesions on his fingers. The attack-rate was 86% for passengers who ate the ham handled by this cook and 0% for passengers who ate ham handled exclusively by another food preparer. Before being served, the ham and omelette had been held at room temperature for 14 h and at 10 degrees C (50 degrees F) for 14 1/2 h Specimens of stool and vomitus from ill passengers, left-over food, and the finger lesions of the cook were positive for Staphylococcus aureus of identical phage types and antibiotic sensitivities. Preformed enterotoxin was detected in the left-over ham and omelette. This outbreak re-emphasises that people with infected lesion should not handle food and that foods must be stored at temperatures low enough to inhibit the growth of bacteria. To ensure against a common foodborne illness incapacitating the entire flight crew, cockpit crew members should eat different meals prepared by different cooks.

Bacterial flora of the hemolymph of the blue crab, Callinectes sapidus: numerical taxonomy

Bacteria isolated from the hemolymph of normal blue crabs were found to be predominantly Vibrio sp., Pseudomonas sp., Acinetobacter sp., Bacillus sp., Flavobacterium sp., and coliforms. Vibrio parahaemolyticus, a cosmopolitan facultative pathogen widely implicated in outbreaks of gastroenteritis related to the consumption of improperly processed seafood, was present in crabs collected between the months of May to November and was identified in up to 21% of the hemolymphs sampled.

Microbiological and other harzards from seafoods with special reference to Vibrio parahaemolyticus

The salient features of some of the more important microbiological health hazards to man from seafoods are reviewed briefly. They include poisoning, indirectly from toxins produced by certain marine algae or more directly by Clostridium botulinum, as well as infection with the marine bacterium Vibrio parahaemolyticus. Local culinary habits play a significant role in such kinds of illness, and food well cooked shortly before consumption is always preferable. Since established customs die hard, safety ultimately depends, not so much on arbitrary microbiological standards, but on hygienic production, correct storage and distribution, and on education in intelligent eating habits.