Assignment 1&2 answers

Assignment1&amp2 answers


Tanningand Skin Cancer

Cases– Individuals with melanoma.

Controls– Individuals without melanoma.


Thestudy is to find out if skin tanning services exposure causesmelanoma. The study becomes valid if a large number of tanningservice users are now suffering from melanoma.


Thisparticular study has serious bias issues in that the controls aredrawn from the local population, while the cases are drawn from allover the country. Ideally, the sample for selection for bothscenarios should be the same. This study will suffer from selectionbias.

Thereis also a point made that the hospital attracts those who havemelanoma. It is quite possible to get a large collection of patientsfrom the hospital. Meaning the number of cases will be good. However,the issue will be with the controls. The controls are individuals whohave used tanning services but do not have melanoma.

Thecase study suggests that the hospital is located in a low incomearea. There is a good chance that many of these have not used atanning service. It is not possible to change the controls to otherpatients in the hospital because only patients with melanoma areavailable. Further the sample size would be very small as far ascontrols are concerned.

Thebias involved would seriously jeopardize any conclusions drawn fromthis study.

Smokingand Diabetes

Cases– Individuals with diabetes.

Controls– Individuals without diabetes.


Thestudy would be valid if a large number of smokers ended up gettingdiabetes.


Onceagain, selection bias is prevalent in this study. The cases areindividuals who have diabetes. Some of them might be smokers whichhelps the study. The controls are however, where selection biascreeps in. The controls are full time hospital employees. There is apossibility that many of the hospital employees might lie about theirsmoking habits. Since they are in a hospital, they probably would notwish to admit that they smoke.

Selectionbias could derail this study.


SixSteps of an Epidemiologic Outbreak

Step1: Detect Outbreak

Outbreakdetection is the primary task here and it starts with confirming thediagnosis. Once this is done, cases are clearly defined and thenidentified (Storm, 2006). This will allow us to identify if anoutbreak has indeed taken place. Once the outbreak has beenconfirmed, preparation for fieldwork begins.

Question:Symptom of Botulism?


Question:Important issues by botulism cases.

Answer:Identifying potential sources of botulism and identifying otherpersons exposed to the same sources.

Question:Changes to press release

Answer:Delete patient names, shorten physician’s quote, replace medicalterms with common terms and add telephone number for contact.

Question:Paragraph that will lead to bias


Question:Would you suspend commercial food services.


Step2: Generate Hypothesis

Collectdata and generate a working hypothesis, identifying patterns in theoutbreak across the demography.

Question:Demographic information

Answer:100 % male. 100 % worked morning shift.

Question:Clinical Information

Answer:100 % drooping eyelids, 78% blurred vision, 44% double vision, 44%upper extremity weakness, 44% respiratory difficulty. 33% lowerextremity weakness.

Question:Unity for X-axis


Question:Demographic information

Answer:100 % male. 100 % worked morning shift.

Question:Type of Outbreak

Answer:Continuous common source

Question:Type of study

Answer:Epidemiologic study.

Step3: Design Epidemiologic Study to Test Hypothesis

Atthis point, a hypothesis has been concluded. Now, it is time todesign a study that can be used to test the hypothesis. See if it isright or wrong.

Question:Characteristics of a good questionnaire?

Answer:Phrased so as to not suggest a response.

Step4: Analyze and Interpret Data

Atthis point data has been collected based on the study. Now it is timeto interpret the data after analysis.

Question:measure of association

Answer:Relative risk.

Step5: Execute Other Studies

Anyother studies related to botulism, such as reviewing the basicbiology of the botulism agent is done here.

Question:Activities that are part of environment health assessment of thematambre.

Answer:Interview the food handlers, collect stool specimens, samples ofimplicated matambre, measure temperature of refrigerators andinvoices for matambre.

Question:Equipment to take for assessment

Answer:pencil or pen, sterile scoops, labels, camera, thermometer and icechest.

Question:Demographic information

Answer:100 % male. 100 % worked morning shift.

Question:Critical control points in the production of matambre

Answer:cleaning the knife and refrigerating the matambre until served.

Step6: Implement Control and Prevention Measure

Inthis step, we know what needs to be done. The plan is put intoaction. Once the plan has been put to action, preventive measures arediscussed. This will prevent future outbreaks.

Question:Control measures other than shutting down the matambre producer

Answer:Recall and destroy all matambre made by producer and explore if otherfoods are also problematic.

Question:Impact measure for Botulism Surveillance

Answer:Number of botulism cases for which food is implicated

Question:Has the Botulism Surveillance failed?



Botulismin Argentina (CB3058). (2013, December 6). Retrieved April 28, 2015,from

Strom,B. (2006). Pharmacoepidemiology.Wiley.