An epidemiologist investigating an outbreak of encephalitis in New York City reports that there have been 17 new cases this week. Which of the following terms best describes the number he report:_______. A. Population at risk of encephalitis B. Incidence of encephalitis C. Determinants of encephalitis D. Prevalence of encephalitis

B. Incidence of encephalitis

Explanation: The term "incidence" refers to the number of new cases of a disease that are identified in a specified period of time, among a specific population at risk. In this scenario, the epidemiologist is reporting 17 new cases of encephalitis that have occurred in New York City over the span of one week. Since these are newly identified cases and not a measure of all the people who currently have encephalitis (which would be prevalence), nor a description of the characteristics or factors associated with the disease (which would be determinants), nor an identification of the group of individuals who could potentially contract the disease (which would be the population at risk), the correct answer is incidence.

Extra: - Incidence is a crucial measure in epidemiology, as it helps public health officials to determine the risk of certain populations in contracting a disease. This information is vital for developing prevention and control strategies. It's usually expressed as a rate, for example, the number of cases per 100,000 people per year. - Prevalence is another important epidemiological measure that refers to the total number of cases of a disease existing in a population at a given time. It takes into account both old and new cases and helps to understand the overall level of disease burden in a community. - Population at risk is a term used to describe the group of people who are not yet affected but are susceptible to the disease in question. - Determinants of encephalitis or any disease are factors that can influence the likelihood of disease occurrence, which may include behaviors, genetics, environmental exposures, and other health-related factors. Determinants help researchers understand the causes of health conditions and design interventions.