On the morning of March 11, the Texas Department of Health (TDH) in Austin received a
telephone call from a student at a university in south-central Texas. The student reported that he and his roommate, a fraternity brother, were suffering from nausea, vomiting, and diarrhoea. Both had become ill during the night. The roommate had taken an over-the-counter medication with some relief of his symptoms. Neither the student nor his roommate had seen a physician or gone to the emergency room. The students believed their illness was due to food they had eaten at a local pizzeria the previous night. They asked if they should attend classes and take a biology midterm exam that was scheduled that afternoon. a. In recording a complaint about a possible foodborne illness, it is important to systematically collect some information.
What would you ask the student?
- When had the “suspect pizza” been consumed?
- At What time during the night did symptoms start displaying?
- Did both boys consume the exact same food in the last 24 hours?
- What had they eaten in the past 24 hours?
- Who have you been in contact with the last 24 hours
- What are the exact symptoms?
- Had anyone they been in contact with also become sick with the same symptoms?
- Where else had they been in the last 24 hours?
TDH staffs were sceptical of the student’s report but felt that a minimal amount of exploration was necessary. They began by making a few telephone calls to establish the facts and determine if other persons were similarly affected. The pizzeria, where the student and his roommate had eaten, was closed until 11:00 A.M. There was no answer at the University Student Health Centre, so a message was left on its answering machine. A call to the emergency room at a local hospital (Hospital A) revealed that 23 university students had been seen for acute gastroenteritis in the last 24 hours. In contrast, only three patients had been seen at the emergency room for similar symptoms from March 5-9, none of whom were associated with the university. At 10:30 A.M., the physician from the University Student Health Centre returned the call from TDH and reported that 20 students with vomiting and diarrhoea had been seen the previous day. He believed only 1-2 students typically would have been seen for these symptoms in a week. The Health Centre had not collected stool specimens from any of the ill students.
Is this an outbreak at the university?
Yes, the definition of an outbreak is an increase of the number of cases over a period of time that is greater than those anticipated. For example, in the information above, the physician “believed that only 1-2 students typically would have been seen for these symptoms in a week” the fact being that 23 Students had been into the emergency room in the last 24 hours. The outbreak should be further investigated as it is unknown if the outbreak could affect the whole community or just the university students who have come forward with symptoms.
On the afternoon of March 11, TDH staff visited the emergency room at Hospital A and
reviewed medical records of patients seen at the facility for vomiting and/or diarrhoea since March 5. Based on these records, symptoms among the 23 students included vomiting (91%), diarrhoea (85%), abdominal cramping (68%), headache (66%), muscle aches (49%), and bloody diarrhoea (5%). Oral temperatures ranged from 98.8/F (37.1/C) to 102.4/F (39.1/C) (median: 100/F [37.8/C]). Complete blood counts, performed on 10 students, showed an increase in white blood cells (median count: 13.7 per cubic mm with 82% polymorphonuclear cells, 6% lymphocytes, and 7% bands). Stool specimens had been submitted for routine bacterial pathogens, but no results were available.
How might you narrow the range of agents suspected of causing the gastrointestinal illness?
Narrowing down what all 23 students have in common would be the first port of call:
The signs and symptoms displayed, the incubation period, where they ate, if they live at the same complex if they have the same water source, laboratory testing of samples of the blood, diarrhoea and vomiting need to be taken, if they attend the same cafeteria, If they use the same stair well. Because Gastro can be transmitted through contact from hands, food, water, surfaces and objects when contaminated with faeces or vomit, these 23 people may have used the same door handle, or the same public computer, all it takes is for one person not to wash their hands. According to the Queensland Health fact sheet, Particles in the air after a vomiting attack can transmit gastro also.
By March 12, seventy-five persons with vomiting or diarrhoea had been reported to TDH. All were students who lived on the university campus. No cases were identified among university faculty or staff or from the local community. Except for one case, the dates of illness onset were March 9-12. (Figure 1) The median age of patients was 19 years (range: 18-22 years), 69% were freshman, and 62% were female.
Figure 1. Onset of gastroenteritis among students, University X, Texas, March 1998. (N=72) (Date of onset was not known for three ill students.)
What would you include in discussions with university officials?
In the discussion with the University Officials, It would be advisable to mention it seems to be confined to the University aside from one community member who is displaying the same symptoms. Talk of the contamination place would be priority, the water supply is municipal as is the sewage, and there has been no breaks in the lines or any roadwork done in the area. Contamination could have spread through food, so the dining establishments on campus would have to be considered and where all of their food come from as well as the hygiene of the staff members who work there. Contact with animals should be looked at as well as the common places which all students who are affected have visited.
The university is located in a small Texas town with a population of 27,354. For the spring semester, the university had an enrolment of approximately 12,000 students; 2,386 students live on campus at one of the 36 residential halls scattered across the 200+ acres of the main campus. About 75% of the students are Texas residents. The university uses municipal water and sewage services. There have been no breaks or work on water or sewage lines in the past year. There has been no recent road work or digging around campus. The campus dining service includes two cafeterias managed by the same company and about half a dozen fast food establishments; about 2,000 students belong to the university meal plan which is limited to persons living on campus. Most on-campus students dine at the main cafeteria which serves hot entrees, as well as items from the grill, deli bar, and a salad bar. A second smaller cafeteria on campus offers menu selections with a per item cost and is also accessible to meal plan members. In contrast to the main cafeteria, the smaller cafeteria tends to be used by students who live off campus and university staff. The smaller cafeteria also offers hot entrees, grilled foods, and a salad bar, but has no deli bar. Spring break is to begin on March 13 at which time all dining services will cease until March 23. Although many students will leave town during the break, it is anticipated that about a quarter of those living on campus will remain.
The signs and Symptoms that are displayed among students all consistent with an acute gastroenteritis infection, the vomiting in 91% of the affected as well as diarrhoea, abdominal cramping headache, muscle aches, and bloody diarrhoea accompanying in some infected. Blood counts, performed on 10 students, showed an increase in white blood cells, which are known for their ability to fight infection in the form of a bacteria or virus. While incubation period and test results of the samples are still unknown, the peak in cases suggests it was a short incubation period. As the gastro is limited to only university students living on campus, and both the water and sewage systems are used also by the community – which infers that the public in the community would also be ill, so it cannot be due to this. From the selection of infected people who all live on campus, it is plausible that they all have a meal plan and since no staff or off campus students eat at the main campus canteen, the contamination may very well have come from the main canteen in the transmission of contaminated food. Since not everyone who ate there became sick, it is plausible to allow the fact that the food handler involved serving the students who have become infected, could have been the cause of the contamination.
Therefore the leading hypothesis is that the students were infected from contaminated food at the main canteen.
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