Modern Epidemics. Salvador Macip

Modern Epidemics - Salvador Macip


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that will settle in their digestive systems and protect them in the future. Hence, there are studies exploring what happens to babies born by caesarean, because these children haven’t had to pass through the vaginal canal that would equip them with their first microorganisms. It’s not yet sure what effect this might have on their future health.

      By convention, microorganisms, like all other living beings, are designated by using a first name (with the first letter capitalized) and a second name, both in Latin. The first is the genus name and the second the species name. The genus name can be abbreviated to the initial alone, and both tend to be italicized. Example: Mycobacterium tuberculosis (or M. tuberculosis) is a species of bacteria of the genus of microbacteria that causes tuberculosis.

      In the domain of health, more and more importance is being given to what’s known as the microbiota, or the set of all the microorganisms each person carries inside (and on the surface). It’s believed that, depending on which microbes inhabit this microbiota, we can be more or less prone to certain illnesses or conditions.

       Secondary effects

      It’s been known for some time now that antibiotics can disrupt the balance of ‘good’ bacteria. Medicines eliminate infections but are unable to distinguish between aggressive and innocuous microbes. Depending on the treatment, even weeks can go by in some cases before the bacterial composition of the intestine, for example, completely recovers. This can then give rise to diarrhoea or new infections caused by other harmful bacteria, especially in people already weakened by illness.

      In recent years, several studies have set about the task of identifying all the microorganisms that are to be found in different organs, generally using modern techniques to read their genes in order to relate them to obesity or illness. These studies give us a general idea of the microbes we carry around with us, although each person’s flora is, in fact, unique. Almost like our DNA. It depends more on the zone in which we live than on our genes, and personal habits have a considerable influence as well. An article published in January 2009 demonstrated that sets of intestinal bacteria vary even between twins. Nevertheless, the members of a family living under the same roof have similar flora. The article also indicated that obesity reduces the diversity of flora, as well as altering the genes and metabolism of microorganisms. It’s speculated that this might have consequences for our health, but we still aren’t sure what they might be.

      This knowledge we are acquiring about the microbes that coexist with us has led to questions about whether they can be used for therapeutic purposes. There are now studies looking into ways of changing the composition of a person’s microbiota as a way of curing illnesses and even regulating the metabolism with the aim of weight loss. The easiest way is to take microbes from a healthy person’s faeces and transfer them to the patient. Informally known as a stool transplant, this isn’t such a simple process as it may appear, because it requires, first of all, filtering out the bad microbes and other contaminants.

      It’s well known that not all microbes are as beneficial as the ones I’ve just described. A group called pathogens, amounting to only 1,415 of all those that exist, have been found to cause infectious diseases in humans. Although they are clearly a minority, their impact on society has been, and is, immense.

      Infections occur when one of these pathogens manages to enter our organism and overcome its defence systems. Problems arise when the microbe starts drawing on the resources of the organisms it has invaded to multiply nonstop. If this isn’t checked fast enough, it will end up interfering with the normal functioning of the body, presenting the symptoms characteristic of each infection, depending on the organs the invader prefers. Some of these symptoms are shared by many infectious diseases, for example, fever, shivers or feeling unwell in general.

      With regard to infections, there’s a series of terms that are frequently used to define their reach. For example, an outbreak is an infection localized among a relatively small group of people, for example, a family, a school or even a village. A typical case would be food poisoning, which tends to affect only those who have eaten food containing pathogenic microbes.

      The next level is an epidemic, which is defined rather arbitrarily as an accumulation of infected people that’s bigger than ‘normal’. For example, if a disease is very rare, a mere handful of cases could be regarded as an epidemic. When an epidemic has spread through more than a continent or even the whole planet, we call it a pandemic. Technically speaking, the WHO officially declares a pandemic only when a disease goes beyond six phases, ranging from detection of the microbe in animals (phase 1) through to the continuing presence of the disease in more than one of the regions defined by the organization (phase 6).


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