Question 1: The primary mode of transmission for C. perfringens is through food that is not properly cooked and/or reheated, stored, cooled, and consumed. The primary course of transmission is through meats that are not thoroughly cooked, cooled, and reheated, such as beef, chicken, and turkey. Meats that are improperly cooked in this manner are highly susceptible to bacterial influence and contamination, which could enter humans upon digestion of the contaminated meat products. This mode of transmission led to the exposure of the group to the bacteria in question and led to a number of infections within the group itself.
Question 2: Within the EATC community, it is highly likely that those infected with the C. perfringens bacteria consumed the exact same type of food, such as a stew, casserole, roast, or soup that was not properly cooked and/or reheated in the first place. This is the most likely epidemic pattern because the same type of illness was experienced across a close-knit group of people who likely consumed the same food in a group setting. In addition, this pattern is likely because the same cross-contamination factors are present, such as utensils shared by all members of the group in acquiring the food.
Question 3: In evaluating the additional information provided, it is evident that the case definition should be updated only to confirm that the primary cause of the bacterial infection is an improperly cooked pork shoulder that was not handled according to health code standards. Based upon the information provided in the case study, it is also evident that those preparing the pork shoulder did not take proper temperatures and health standards into consideration when preparing the meat, so that when it was served to the group, it was contaminated with said bacteria. The case definition should be updated accordingly to accommodate the most recent findings in the case evaluation.
Question 4: In spite of the new data and information provided with the update, the hypothesis regarding the epidemic remains the same, as the food preparation was the primary cause of the creation and spread of the bacteria to begin with and was not caused as a result of an already dormant bacterial strain that existed in the meat prior to its preparation. Inadequate food preparation and formation of the bacterial strain remains the chosen hypothesis for this case.
Question 5: In consideration of the food handling investigation, a number of problems were discovered that led to the bacterial outbreak. To be specific, there was inadequate preparation of the pork shoulder from start to finish, as there was significant lag time between the time that the pork shoulder was thawed to the time it was cooked and then reheated. Each of these circumstances was significant enough to serve as a breeding ground for bacterial growth. During the preparation phase, it was also determined that food temperatures were not optimal for cooking the meat and maintaining its temperature afterwards. During the reheating phase, it was determined that the pork did not appear to look as it should in this state, so it was rewarmed and served to the group. Therefore, in spite of questions regarding the pork’s appearance, it was nonetheless served. It is likely that because the pork was covered in barbeque sauce, any problems with its appearance were not detected by the group. Based upon these findings, it is important to note that the food handling and cooking methods used by the kitchen in question were unacceptable and below required health and safety standards. This placed the entire group of people who were to consume the food at a much greater risk for bacterial contamination.
Question 6: With the case example, it is not necessary to conduct a more thorough epidemiology-based investigation, as the conditions were ripe for bacterial contamination and consumption by the group. Under these circumstances, it was strongly evident that the food preparation staff was woefully ill-prepared to cook the pork shoulder in the proper manner without any risk of bacterial contamination. With the manner in which the pork shoulder was prepared, it is not surprising that it was contaminated in the process, which is not only cause for concern in this example, but for other food that is prepared by the kitchen staff in question. From this perspective, an epidemiology study would be futile because the necessary facts have already been derived from the evidence and knowledge that have been discovered.
Question 7: There are a number of important differences between a case control study and a cohort study. For example, a case control study is typically described as establishing two groups, one which is identified with a specific problem or condition (the case group) and one without the problem or condition (the control group). These two groups are compared and contrasted to determine the differences between the groups and the underlying causes of the condition or problem in question. A cohort study is best defined as a group of individuals who have one or more similarities and are recorded or tracked over a period of time. This group of individuals is often exposed to one or more stimuli and the responses are recorded for research purposes. This type of study will enable a specific group of people to be tracked over a period of time to answer questions and/or solve problems within the group.
Question 8: In evaluating the conditions associated with exposure and disease within a given cohort study, it is important to examine what is known as the attack rate. This rate is described as the percentage of people who acquired the illness or condition under the chosen conditions and criteria. This practice is also known as relative risk and is best described as the ratio of those who acquired the illness or condition versus those who did not, or those who consumed the food in question versus those who did not. The relative risk is important in determining the strength of the bacteria and its overall influence on the population group under examination. These factors play a critical role in shaping the progression of the condition and what risks are involved in this practice.
Question 9: Based upon the readings and the case example provided, it is likely that the best possible study scenario would be the cohort study because the population is isolated to a small group of people who were directly exposed to the contaminated pork shoulder product. This requires a select group of individuals with the same level of exposure to the pathogen or contaminant and a measure of whether or not their exposure led to symptoms and illness. This is the most feasible opportunity to further examine the different aspects of the study group and to determine if there are any other conditions (external or internal) that impact bacterial exposure and symptoms. It is important to determine how these elements align with the overall hypothesis that is developed because this will demonstrate the ability of the study to identify symptoms, develop statistics, and convey results. These elements are critical in shaping the overall dimensions of the study and its ability to be effective in determining the extent of exposure to the bacteria, the subsequent risk, and the outbreak that was observed.
Question 10: For this particular study, the group to be included would be all individuals who consumed the pork shoulder meat in the case example. This group would provide the most feasible opportunity to explore the likelihood of symptoms and the measurement of risk for this given population. One key advantage is that the group is small enough to develop a detailed study with the appropriate criteria to determine bacterial contamination and subsequent disease-related risk. This is an important and meaningful toll in developing evidence which further supports the hypothesis and the study objectives. These elements also play a role in shaping the study environment and in measuring the different common criteria associated with this particular group and their exposure to the bacteria.