Epidemiology: what it is and how it studies diseases

For a few weeks now, a certain virus that many of us thought wasn’t going to be for so long ended up giving us a “pleasant” surprise by inviting us to stay home. Not out of laziness or because it hasn’t been a good day, but because it turns out that the streets are, at the moment, potentially contagious.

Given the alarming situation we find ourselves in, it is no surprise that people are wondering about the symptoms, incidence, progression of infections, incubation and elimination period and others. VOCID-19 virus factors.

These questions have their own field of study. Epidemiology is the biomedical science responsible for studying the distribution, Frequency and conditions of onset and progression of a disease, and then we will look more deeply into what it is.

    What is epidemiology?

    Epidemiology (from the Greek “epi”, “envelope;” we give “,” people “and” logos “,” science “) is the study of the occurrence and distribution of events, states and processes. related to health in the population. it is medical science that studies diseases and their course in the population as a whole. Epidemiologists study the distribution, frequency, and factors that influence and determine the progression of the disease in a variety of people.

    The place of epidemiology in biomedical sciences is very important, because it serves as a bridge between the health sciences and the social sciences. It integrates both biomedical and social methods and principles to study health, control diseases in the population and study their socio-economic and biomedical effects.

    Although in its origin epidemiology was born to study epidemics of infectious diseases, such as cholera, Spanish flu or plague, today also includes diseases not necessarily caused by bacteria and viruses, such as cancer. lung damage due to smoking, addictions, as well as the onset of mental disorders such as bipolar, anorexia nervosa or depression, among others.

    What is taken into account when studying diseases?

    Epidemiologists, when studying a disease, whether caused by a living pathogen such as bacteria or by habits of the population, such as sedentary lifestyle and smoking, consider a number of factors. models of the medical or psychiatric condition to be studied:


    with time it refers to when it occurs, especially if it is a disease with a possible contagious cause, Being able to have your highest points at a certain time of the year.

    2. Location

    It is the physical place, like a city, a country, the characteristics of the area where there were more cases

    3 people

    People refer to those who are more likely to manifest a certain biomedical condition, that is, the risk group.

    Usually, in contagious diseases, the groups most at risk are babies and the elderly.

    epidemiological methodology

    The epidemiological methodology uses the observational scientific method because this discipline, to increase its knowledge, must use real cases, which have occurred in the population. That is, look at how many new cases of the disease there are, what individual characteristics make these cases manifest the disease, which means that elsewhere there has not been as much incidence …

    The epidemiological method uses fundamentally quantitative techniques. Epidemiological studies do not modify or manipulate the factors that affect peopleUnlike a laboratory experiment, in which the characteristics of the person, the type of stimuli or environmental factors to which they are subjected, among others, are controlled.


      Epidemiology is a fundamental field of biomedical sciences, as it allows us to understand the evolution of medical conditions, whether or not they are caused by infectious agents. This discipline has the following objectives.

      1. Determine the extent of the disease

      pretend measure what is happening in the population, what are the death rates, incidence and prevalence of diseases, In addition to the prevalence of risk factors.

      All of this makes it possible to know the specific characteristics of health or disease in a population, as well as to be able to follow over time how changes occur in these characteristics.

      For example, studying the epidemiology of why there is more mortality in one region than another, what genetic and environmental factors make a population more vulnerable, or what eating habits or risks involve would explain the incidence of the condition. medical.

      2. Identify the determinants of the disease

      As we have seen, since its inception, epidemiology has sought to find out the cause of the appearance of a certain state of health and the causes affecting the pathological process.

      Essentially, is responsible for identifying risk factors when it comes to being able to manifest a medical illness or psychological disorder.

      3. Complete clinical images

      In clinical medicine, epidemiology has a very useful application, because it makes it possible to specify, by means of epidemiological and statistical criteria, what the patient is suffering from.

      The case of rapeseed oil poisoning is an example.. Through epidemiological research, it was possible to discover that the disease manifested by thousands of people was caused by the consumption of this particular oil.

      4. Detect new diseases

      The emergence of new cases of an unknown disease is studied by means of an epidemiological method.

      This was the case with HIV / AIDS. It was discovered in patients with rare pneumonia, which only affected people with symptoms of immunosuppression.

      5. Evaluate the effectiveness of the health intervention

      epidemiology is applied to know the effectiveness of any type of health intervention, Both prevention and treatment.

      6. Contribute to health planning

      While the above applications already contribute to health planning, epidemiology is also used, specifically, to know the specific needs of health services, for example in designing health plans.

      In addition, also it is used for the evaluation of results after health intervention policies, Analyze the objectives set in the previous plans.

      7. Contribute to training

      Epidemiology is not just about finding out how a disease occurs, what is its prevention, which population is at risk, and other aspects directly related to the biomedical condition.

      too much aims to train health professionals so that in the event of the onset of the disease, they will know, by consulting the biomedical literature and knowing the symptoms of a condition in question, what to do and how to prepare.

      Some key terms

      In the language of epidemiology, terms are collected which have a specific meaning when it comes to pathological processes. Below, we’ll take a closer look at some of them.

      1. Epidemic

      A disease is considered an epidemic when there are a very large number of people who simultaneously present with this medical condition.

      2. Pandemic

      A pandemic is a large-scale epidemic that spreads widely and becomes present all over the world. The case of VOCID-19 in March 2020 is one example.

      3. Endemic disease

      An endemic disease is a disease that occurs in greater numbers in a given population, Although this does not necessarily imply that it has manifested itself in all individuals.

      An example of an endemic disease is the case of thalassemia, a type of anemia that is found in many Mediterranean countries, which finds more cases in southern Spain and Italy.

      4. Incidence of disease

      This term refers to the number of new cases of an individual disease in a population during a given period.

      5. Prevalence

      The prevalence of a disease is given by the total name of new and existing cases detected in a specific population, Also for a certain period of time.

      6. Brot

      An epidemic is understood as the appearance of new cases in a specific region, usually over a short period.

      When we talk about an epidemic, it is stated that more cases are occurring than before, although this does not necessarily have to refer to the onset of a new disease. This same disease may have occurred earlier, but very sporadically.

      About contagious diseases

      To cause disease, a pathogen, such as a bacteria or virus, must find an individual in which to lodge. the, grows and reproduces, affecting the health of the individual and producing the symptoms of the disease.

      Needless to say, if there are fatal diseases, in most contagious diseases, if the customer dies, so does their tenant, which is not beneficial to them. If they are to kill the host, these organisms must first be able to reproduce and pass to another organism, otherwise they will eventually become extinct.

      It is for this reason that most host-dependent pathogens must adapt and coexist with the individual in which they are housed. This is not a symbiotic relationship, but parasitism, since the host individual, even if he does not die, will be injured.

      The pathogen, when well adapted to the individual, takes what it needs to be able to continue living and uses the host’s own biological structures to feed or reproduce, as would be the case with viruses. to cells during viral reproduction. The damage these pathogens can cause is diverse, ranging from simple temporary symptoms to chronic infections that must be treated urgently and intensely.

      Bibliographical references:

      • Hernández-Aguado, Ildefons, Lumbreras, Blanca and Jarrín, Immaculada. (2006). Epidemiology in the public health of the future. Spanish Journal of Public Health, 80 (5), 469-474. Retrieved March 19, 2020 from http://scielo.isciii.es/scielo.php?script=sci_arttext&pid=S1135-57272006000500005&lng=es&tlng=es.
      • Fernández, E. (sf). What is epidemiology used for? esteve.org. Retrieved from https://esteve.org/wp-content/uploads/2018/01/13113.pdf.

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