(Case Study Report)
Part 1
Question 1. A. What are the key steps of the investigation of an outbreak?
According to the Centers for Disease Control and Prevention, epidemiologists follow a systematic approach in order to pull off a “quick and clean” outbreak investigation (CDC, 2012). The following procedure includes the ideal system in carrying out an outbreak investigation: (1) field work preparation, (2) confirm the existence of the reported outbreak, (3) vet the current diagnosis, (4) conduct a working definition of the case, (5) start recording individual cases, (6) apply descriptive epidemiology, (7) construct a hypothesis, (8) verify the hypothesis, (9) match the hypothesis with the laboratory results and other existing environmental studies, (10) plan for possible preventive measures, (11) monitor the implementation, and (12) link the findings (CDC, 2012).
Question 1. B. Can the team determine whether or not they are dealing with an outbreak at this stage? What additional information would they need?
The team can already determine that they are dealing with an outbreak since their recent findings showed that the disease has infected a cluster by households. The report was also verified through the clinical laboratories that are existing in the city. Therefore, at this point, it was clearly established that there is an acute hepatitis outbreak in Provo, Utah.
Part 2
Question 2. A. What are the possible agents that could be causing this outbreak? For each, list the clinical and epidemiological elements that are compatible with the diagnosis and those that go against it.
The World Health Organization (WHO) confirmed that there is a viral hepatitis. Possible agents that could cause an acute hepatitis outbreak are unprotected sex, blood transfusion, unsterile injection procedures, and hazardous food and water (WHO, 2016). Clinical elements that are compatible with the outbreak include fever and urine infection.
Questions 2. B. How would it be possible to confirm the diagnosis?
The diagnosis can be confirmed through a series of laboratory examination, careful study of the patients’ reports and through establishing rapport and cooperation with the clinical partners within the city.
Part 3
Question 3. A. What kind of elements should be contained in a case definition?
The case definition must include clinical elements to confirm the outbreak and to come up with possible preventive measures to hinder its spread.
Question 3. B. What case definition could be suggested to look for cases?
The case definition must include the criteria time, place and person to be able to look for cases which can contribute to the success of the study.
Part 4
Question 4. A. What are the potential options available to search for cases during an outbreak investigation?
There are many ways to search for cases during an outbreak. The best way is through surveillance system. According to Henning (2004), outbreaks can be verified through surveillance systems because it makes use of the existing health data to analyze the statistics of the outbreak.
Question 4. B. What case finding strategy could be adapted to this specific situation?
If surveillance system is considered, searching for cases may be a lot easier if the group will coordinate with the local clinics so they can have access to the real time data and statistics. Having enough and proper data can contribute to a more concise, comprehensive and credible case report.
Question 4. C. What minimum information will be required for each case? How should this information be organized?
Getting the demographic characteristics of the people in the area is the most vital information needed to assess the disease outbreak. To have enough data, the group may go to the local clinics in Provo, Utah in order to have access to the demographic characteristics of the patients. The most important characteristics are gender, age, onset date, as well as the signs and symptoms that are prior observed.
Question 4. D. How would you analyze the data?
The collected data may be analyzed through performing different statistical procedures and linking it with the clinical observations.
Part 5.
Question 5. A. How can the epidemiological information contained in these figures and this table be described?
The figure shows that the cases of Hepatitis started to come up on the third week of January. The reported cases continued to increase until the fourth week (February) were the number of reports are at its peak. It was also on the second week of February when deaths have been reported. These deaths can possibly be the result of unreported signs and symptoms that patients experienced.
Question 5. B. How can this information be interpreted?
The number of hepatitis cases is in an increasing trend from the third week of January up until the second week of February. The number of deaths called the attention of the people in the city, as well as the clinical practitioners which led to the decrease in cases. The actions of the health sector in the subtle prevention of the disease outbreak contributed to the lessening number of hepatitis cases.
Figure 2 shows that neither of the two water supply systems actually contribute to the worsening hepatitis outbreak in the city. As it can be seen in the figure, those areas with underground supply have different attack rates, and even those areas near the water pump system have already reported cases of hepatitis.
Question 5. C. What are the potential hypotheses that could be generated on the basis of these data?
The two types of water systems in Provo, Utah has nothing to do with the existence of Hepatitis E outbreak in the city.
Question 5. D. How could these hypotheses be tested?
Part 6.
Question 6. A. What are the options available to the investigators in terms of study design? Which one may be preferable? Why?
The investigators may consider two terms of study design—either by cohort (age group) or by using a case-control study. It is preferable to use the first one (cohort-based study design) since the table in the fifth part already revealed age statistics of the patients.
Question 6. B. What kind of study participants should be recruited for this study? What criteria should be used to select them?
The participants must be of different age, and all cohort or age groups must be fairly represented. To avoid having slanted results, other demographic characteristics other than age must be considered null.
Question 6. C. What kind of data should be collected among study participants?
Both quantitative and qualitative data must be obtained from the participants to have more credible and concise results.
Part 7.
Question 7. A. How should the data be analyzed? What measure of association need to be calculated? How?
The collected data must be analyzed in a mathematical or statistical manner to avoid hasty generalization. Odds ratio is the most preferred procedure to check on the confidence interval in the participants’ responses (Szumillas, 2010).
Question 7. B. Calculate the appropriate measure of association. How do you interpret the results?
Through the odd-ratio approach, the abovementioned hypothesis deemed to be true after showing no association between the current water systems and the increase in number of the hepatitis E cases.
Question 7. C. Would you conduct additional investigations?
Additional investigations are also necessary to re-evaluate the findings and to verify the results of the study.
Part 8.
Question 8. A. Are the results of this investigation compatible with what was already known about hepatitis E outbreaks?
According to the World Health Organization (WHO), one of the key facts of Hepatitis E is that it can be transmitted through faecal-oral route in a form of a contaminated water (WHO, 2016). Therefore, the results of the investigation are a bit unaligned to what was already known about the other hepatitis outbreaks that were studied.
Question 8. B. Did we learn new features of hepatitis E through this outbreak investigation?
While it was already mentioned that Hepatitis E Virus (HEV) can be transmitted through water contamination, the results of the investigation shows that not all hepatitis outbreaks are caused by contaminated water pipelines.
Part 9.
Question 9. A. To what audiences should the results of this investigation be reported?
The results of the investigation must be reported bigger health agencies like the World Health Organization (WHO) to check on other possible sources of the outbreak and to gather other possible support to further widen the investigation.
Question 9. B. What do you expect of the various audiences to whom the results of this outbreak investigation will be reported?
Audiences may or may not be enticed to conduct more investigation to figure out other sources of the virus other than through water contamination.
Question 9. C. What media will you be using to reach each of these audiences?
The reporting must be held face to face in order to have enough explanation on the findings of the investigation and to be able to answer the queries of the audience immediately. Setting immediate appointments with the required audiences is important since the investigation aims to answer the demand towards better health.
Question 9. D. What should be the short term, medium term and long-term recommendations following this outbreak?
A short term recommendation could be pipeline maintenance to make sure that the water which flows from the source down to the house sinks is not contaminated. Medium term could be providing vaccines against Hepatitis E. Short term is through providing knowledge to the people of Provo, Utah through hosting small discussions and through school caravans.
Question 9. E. What this outbreak investigated too late?
If the outbreak was investigated too late, the increase in the number of hepatitis cases might have continuously increased and the number of deaths might have become higher. The outbreak could also affect the nearby cities in Utah, further affecting the health of more people.
References
2x2 Contingency Table with Odds Ratios, etc.. (2013). Vassarstats.net. Retrieved 17 July 2016, from http://vassarstats.net/odds2x2.html
Brookmeyer, R. & You, X. (2005). A Hypothesis Test for the End of a Common Source Outbreak.Biometrics, 62(1), 61-65. http://dx.doi.org/10.1111/j.1541-0420.2005.00421.x
Guidelines For Viral Hepatitis Surveillance And Case Management | Statistics & Surveillance | Division of Viral Hepatitis | CDC. (2016). Cdc.gov. Retrieved 17 July 2016, from http://www.cdc.gov/hepatitis/statistics/surveillanceguidelines.htm
Henning, K. (2004). Overview of Syndromic Surveillance What is Syndromic Surveillance?. Cdc.gov. Retrieved 17 July 2016, from http://www.cdc.gov/mmwr/preview/mmwrhtml/su5301a3.htm
Hepatitis E. (2016). World Health Organization. Retrieved 17 July 2016, from http://www.who.int/mediacentre/factsheets/fs280/en/
Odd Ratio Calculator. (2016). Retrieved 17 July 2016, from https://www.medcalc.org/calc/odds_ratio.php
Outbreak Investigations—A Perspective - Volume 4, Number 1—March 1998 - Emerging Infectious Disease journal - CDC. (2016). Wwwnc.cdc.gov. Retrieved 17 July 2016, from http://wwwnc.cdc.gov/eid/article/4/1/98-0104_article
Principles of Epidemiology: Lesson 6, Section 2|Self-Study Course SS1978|CDC. (2012). Cdc.gov. Retrieved 17 July 2016, from http://www.cdc.gov/ophss/csels/dsepd/ss1978/lesson6/section2.html
Szumilas, M. (2010). Explaining Odds Ratios. Journal Of The Canadian Academy Of Child And Adolescent Psychiatry, 19(3), 227. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2938757/
WHO,. (2016). WHO | Hepatitis: frequently asked questions. Who.int. Retrieved 17 July 2016, from http://www.who.int/csr/disease/hepatitis/world_hepatitis_day/question_answer/en/
