Outbreak investigation — MCQs

You have been asked to quantify the relative risk of developing bacterial meningitis following exposure to a patient with active disease. You analyze 200 patients in total, half of which are controls. In the trial arm, 30% of exposed patients ultimately contracted bacterial meningitis. In the unexposed group, only 1% contracted the disease. Which of the following is the relative risk due to disease exposure?

A research group designed a study to investigate the epidemiology of syphilis in the United States. The investigators examined per capita income and rates of syphilis in New York City, Los Angeles, Chicago, and Houston. Data on city-wide syphilis rates was provided by each city's health agency. The investigators ultimately found that the number of new cases of syphilis was higher in low-income neighborhoods. This study is best described as which of the following?

An 18-year-old female college student is brought to the emergency department by ambulance for a headache and altered mental status. The patient lives with her boyfriend who is with her currently. He states she had not been feeling well for the past day and has vomited several times in the past 12 hours. Lumbar puncture is performed in the emergency room and demonstrates an increased cell count with a neutrophil predominance and gram-negative diplococci on Gram stain. The patient is started on vancomycin and ceftriaxone. Which of the following is the best next step in management?

A researcher is trying to determine whether a newly discovered substance X can be useful in promoting wound healing after surgery. She conducts this study by enrolling the next 100 patients that will be undergoing this surgery and separating them into 2 groups. She decides which patient will be in which group by using a random number generator. Subsequently, she prepares 1 set of syringes with the novel substance X and 1 set of syringes with a saline control. Both of these sets of syringes are unlabeled and the substances inside cannot be distinguished. She gives the surgeon performing the surgery 1 of the syringes and does not inform him nor the patient which syringe was used. After the study is complete, she analyzes all the data that was collected and performs statistical analysis. This study most likely provides which level of evidence for use of substance X?

The occupational health department at a hospital implements new safety precautions to prevent laboratory-acquired infections. One of the new precautions includes disinfecting the microbiology laboratory benches with 70% ethanol before and after use. This measure is most likely to be effective in preventing the transmission of which of the following viruses?

A 37-year-old man presents to the emergency department after he cut his hand while working on his car. The patient has a past medical history of antisocial personality disorder and has been incarcerated multiple times. His vitals are within normal limits. Physical exam is notable for a man covered in tattoos with many bruises over his face and torso. Inspection of the patient's right hand reveals 2 deep lacerations on the dorsal aspects of the second and third metacarpophalangeal (MCP) joints. The patient is given a tetanus vaccination, and the wound is irrigated. Which of the following is appropriate management for this patient?

A scientist is studying the influenza A virus. He focuses on two strains – one from humans (H7N1) and one from horses (H3N8). He takes cells from chickens and coinfects these cells with both influenza strains. From these chicken cells, the scientist isolates a new strain and finds that this new strain can infect human cells. He further characterizes the new strain’s hemagglutinin and neuraminidase description as H7N8. What term best describes the process that underlies these experimental results?

A 26-year-old patient presents to your office with rhinorrhea that you believe to be viral in origin. He respectfully requests treatment with antibiotics, and he demonstrates an understanding of the risks, benefits, and alternatives to treatment. His mental status is intact, and you believe him to have full decision-making capacity. Which of the following is the best course of action?

A regional academic medical center has 10 cases of adenovirus in the span of a week among its ICU patients. A committee is formed to investigate this outbreak. They are tasked with identifying the patients and interviewing the care providers to understand how adenovirus could have been spread from patient to patient. This committee will review charts, talk to the care provider teams, and investigate current patient safety and sanitation measures in the ICU. The goal of the committee is to identify weaknesses in the current system and to put in place a plan to help prevent this sort of outbreak from reoccurring in the future. The committee is most likely using what type of analysis?

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?