Outbreak: Disease Detective

Part 1 

Question 1: 

What symptoms are you showcasing? 

When did these symptoms begin showing? 

Did you consult a physician? 

Have you undergone any tests? 

Which treatments have you received? 

Who else is sick? 

When did they become ill? 

What symptoms are they showcasing? 

Can you please provide you schoolmates’ addresses and contacts? 

What do your friends think made them ill? 

How can I reach you later? 

I appreciate that you notified me about your illness. 

Question 4: 

I think that these cases do present a gastroenteritis outbreak at the university because of the over 40 cases margin of disease occurrence in 2 days. I also think these cases represent an outbreak because typically, only a handful of students visit the emergency room or Student Health Center with gastroenteritis cases. 

Question 6: 

I could narrow down the range of causal agents suspected for the spread of the gastrointestinal illness by using information about the incubation period, testing of vomit, blood, and stool, test the suspected foods, check the duration of symptoms amongst the students, and look for predominant signs and symptoms. 

Question 11: 

The pathogen 

The bloody stools, fever, diarrhea, vomit, fecal occult blood, and fecal leucocyte signs suggest that the students have acute gastrointestinal infection. Diarrhea and vomiting indicate viral rather than parasitic infection. The rapid increase and fall of the cases suggest a viral infection due to a short incubation period. 

The mode of transition 

On-campus, the possible transmission is through food and drink from the main cafeteria where most students affected ate at the deli bar. Person to person or water contamination spread is impossible because there would be community cases, roommates were not affected, and the faculty had no cases. 

Sources 

Viral agents in the salad and sandwiches at the deli might be the standard food item. 

Period of interest 

The earliest reported cases and the latest cases show that the onset of the illness was from 10th March to 12th March indicating the incubation period for gastroenteritis virus that lasts one day to a week. 

Final hypothesis: between 5th March and 10th March, there was a viral spread through food at the deli in the main university cafeteria. 

Question 12: 

I would use a controlled epidemiologic evaluation to investigate the deli and the main cafeteria as the environment, test the water, leftovers, and the food from the deli bar and the cafeteria. 

Question 14: 

Yes, I agree with the decision to close the deli bar until evaluators can assure that they implement safer practices while limiting the upsurge of cases. The actions that I would take include investigating the source to avoid future outbreaks through a more specific epidemiologic inquiry. 

Part 2 

Question 15: 

The advantage of undertaking a case-control study rather than a cohort study is because a case-control study allows me to focus on a limited number of sample students and get a quality participation rate. A case-control study is faster and less costly. However, conducting a cohort study would be costly and time-consuming because it would include all students within the campus to compare those that ate at the deli bar versus those that did not. 

Question 16: 

I would define a case of this study by basing on the person showing predominant signs or symptoms such as diarrhea and vomiting to exclude any person that was well. Hence any university student that presented diarrhea symptoms (constitutes of more than three loose stool for 24 hours) and vomiting from 5th March at the Student Health Canter or emergency room is a case for this study. 

Question 17A: 

56% of the cases reported exposure to the food at the deli bar during the suspected mealtimes. On 9th March, cases were more likely to have visited the deli bar than the control group at a ratio of 11:6. On 10th March, cases verses control ratio was at 8:1. 

Question 17B: 

When the investigators match on a possible risk factor, they inhibit the evaluation of that risk factor. When matching ill and well roommates eliminates the likelihood of finding out if the diarrhea was transmitted through the person-to-person spread. The other factor to affect the validity of measured association is the possible overmatching where the case and control eat meals together and share exposures; hence they are non-discordant pairs. The third factor is the selection bias, where the selection was not random but rather based on the availability of students. Cases might have been excluded from the study may result in an odds ratio that is impossible to determine. 

Question 19: 

Face-to-face interviews 

The advantage is that the participants report a higher response rate with higher accuracy than the other methods. The disadvantage is the interviewer’s bias, lack of anonymity, tiring to track down participants, and dishonest presentation of information to please the interviewer. 

Telephone interview 

The advantages include less cost, more accurate recording, and more accessible to track than face to face and higher response rate than self-administered,. The disadvantages include lack of anonymity, interviewer bias, more costly than self-administered, and subjects attempting to please the interviewer. 

Self-Administered Interviews 

The advantages include honest responses, less time-consuming, less costly than face to face, and increased anonymity. The disadvantages include errors in responding due to lack of guidance, lower response rates, and time-consuming to develop the method. 

I would highly recommend the self-administered interviewing 

Question 23: 

I would recommend all of the following actions. 

Throw away the leftovers to prevent another outbreak but not in the long-term. 

Disinfect and clean to control the current break down but needs to be consistent, reducing the possibility of a future outbreak but not long-term. 

Food handlers should test to effectively control the current outbreak while preventing the shedding of the virus. However, it is costly and shall not contain future outbreaks. 

Educating food handlers on proper food handling procedures is a long-term intervention that prevents current and future outbreaks. However, it might be costly. 

Developing a food handler’s policy is a compelling long-term intervention that might not be effective in handling current outbreaks while it shall be time-consuming. 

Question 24: 

The local health department – to offer expert insight into control measures for foodborne diseases 

Food handlers – provide feedback on how the policy shall affect their work 

Cafeteria managers – to answer staff policy questions and implement it 

The university representatives – they shall handle legal implications of policies affecting employees and future incidences amongst students 

Union representatives –to give insights on legal implications of the policies