Provide a critical appraisal of the following paper.

Utsi L, Smith S, Chalmers R, Padfield S. Cryptosporidiosis outbreak in visitors of a UK industry-compliant petting farm caused by a rare Cryptosporidium parvum subtype: a case-control study. Epidemiology and infection 2016;144(05):1000-1009.

Address the below questions in your response.  Unlike the short question and answer format of exercise 5, for this assessment synthesise your answers to the questions in an essay format including an Introduction and Conclusion.  

•    What is the purpose of the study?
•    What is the study design? Is this an appropriate study design for the purpose of the study? Justify your answer.
•    Describe the sample. What is the target population?
•    Is the sample representative of the target population? Why or why not?
•    What are the study factors? How was information on these obtained?
•    What are the outcome factors? How was information on these obtained? 
•    Identify potential confounders in this study.
•    Were they identified by the researchers? If so, how were they managed?       
•    Identify potential biases in this study.
•    What effect might these have had on the study?
•    What statistical methods were used? Were these appropriate?
•    Describe the study strengths/weaknesses/limitations.
•    What are the main results from this study?
•    Taking into consideration the study strengths and weaknesses, do you think they are valid?
•    What are the authors' conclusions?  Do you agree with them?
•    Assuming that the results of this study are valid, what do you think are the most important public health implications from this paper?

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