Epidemiology can be defined as a study of determination of states of health, events in the population of humans, its distribution as well as the application of such studies in control as well as the prevention of any health related consequences.
Information on epidemiology plays a very essential role in completing the objectives of public health that is aimed for promoting mental, physical as well as well-being inside the population.
The steps in the epidemiological process are as follows:
1. Data sources- It is the first step in the epidemiological process to know how the data will be obtained. Birth and mortality statistics are calculated from vital records. It gives health related information, hence vital in many countries. Census data, birth certificates, death certificates, and surveillance data come under this category.
2. Rate adjustment- Rates are an essential factor for epidemiological studies. Age adjustment is done by direct or indirect methods. A standard population is considered as an external population that serves as a reference.
3. Comparison groups- The exposed group is compared with the unexposed group to decide, whether the disease rate is the result of suspected risk factors. This comparison is important for observational studies to control for confounding variables or factors.
The disease progression is the complex process between causal agents, susceptible persons, and the environment. These three together are called the epidemiologic triangle. All these three elements are dependent on each other. Variation in any one of the factors may change the others too.
The agent is an animate or inanimate factor whose presence or absence is necessary for disease progression. The agents can be infectious, chemical or physical. The infectious agents are commonly microbes such as bacteria, viruses, fungi, and parasites. The chemical agents include heavy metals, toxic chemicals and pesticides. The physical agents are radiation, heat, cold and machinery.
The host is a living species that is being susceptible for the infection caused by the agent. There are several factors that make the host susceptible to be infected. These factors are genetic susceptibility, age, sex, and immune status and life style patterns.
The conditions that internally or externally influence the given host are known as environment. The factors that are the part of environment are climate, plant, animal life, human population distribution, socioeconomic factors, and working conditions.
The responsibility of the nurse epidemiologist is to find out the reason of infection, and take necessary interventions. Norovirus causes viral gastroenteritis in humans. The virus infects through contaminated, food, water, droplets, and from person to person contact. The symptoms of norovirus infections are nausea, vomiting and watery diarrhea.
It may be possible that the food served at the event was contaminated. The students ate that contaminated food and got infected. If the persons that served and prepared the food are infected then it is possible that the food got infected by the droplets or the aerosols.
The list of the people that attended the event may reflect that if anyone present is infected prior to the event or not. If anyone prior infected is present in the event, then it may be possible that the other got infected through person to person contact.
The faculty and the students that are not present at the event may also be the source of infection. It is possible that the infection came from the classroom. So, the people absent at the event may also be the infection source.
Hence, the correct answer is option