Viral diseases have accompanied humanity for centuries. Viral particles are found in coexistence with human beings and infect them, sometimes seasonally, and sometimes in outbreaks or epidemics.
Some viruses are more common than others and have a wider distribution. We have all heard of influenza, for example, whether we live in America, Europe or Asia. Due to their importance, in this space we present the three viral diseases with the highest incidence worldwide.
As is usual in this type of topic, it never hurts to remember a little bit about what a virus is and how it works.
- Viruses are microscopic acellular agents that can only reproduce within the cells of an organism.
- They are composed of DNA or RNA, and proteins that give them a three-dimensional structure, a physical form.
- These microscopic organisms hijack infected host cells: they replicate their own genetic information in them and are released to infect other cells and organisms.
Thus, the existence of a virus cannot be conceived without its host. Moreover, there is an interesting debate about whether to even consider them as living beings. Beyond questions that border on the philosophy, it is time to focus on the three most common viral diseases in humans.
1. The common cold
The common cold is a type of respiratory infection that takes the crown in terms of prevalence. According to studies compiled by PMC, it affects adults two to six times a year and children six to ten times a year. We go further, since this pathology is the cause of 30% of school absenteeism and 40% of work absenteeism.
There are more than 200 different types of virus that cause the common cold. Even so, the most common is the genus of rhinovirus, which causes more than 50% of the typical clinical pictures.
Rhinoviruses consist of a capsid with four types of proteins and a single-stranded RNA molecule, giving them a circular shape similar to a golf ball.
The characteristic symptomatology of the common cold is, unfortunately, known to all: cough, nasal congestion, pharyngitis and sneezing. A curious fact is that, due to the immense amount of viruses that generate this pathology, a vaccine is totally unfeasible.
2. The flu
Influenza is an infectious disease caused by influenzavirus A or influenzavirus B, genera of the family Orthomyxoviridae. These viruses are more complex than those that cause colds, as they have seven or eight reverse RNA fragments instead of a typical chain. Their shape is also tiny and spherical.
Influenzavirus B is less aggressive and has a lower mutation rate than Influenzavirus A. The only animal capable of being infected with this virus, apart from humans, is the seal.
The overall incidence (i.e. the number of people who can be infected at any given time) is estimated at 20 %, but in certain population groups it can be as high as 50 %. These data cause vertigo, as at times of high prevalence (in winter) up to half of a particular group may have influenza.
The symptomatology is again known by all: very similar to the cold, but with a greater indisposition and fever associated.
3. Viral gastroenteritis
There are several causes of gastroenteritis, and viruses are one of them
This pathology is the cause of 70% of diarrhea in the pediatric age groups globally.
Norovirus is the genus of RNA virus that causes most of the outbreaks in the United States. Typical symptoms include nausea, vomiting, abdominal pain and watery diarrhea.
Although infection with this pathogen can be extremely uncomfortable, the prognosis is very positive. It is estimated that in two or three days most people recover without major complications.
A world of microorganisms
As we have seen, there is a vast world of viral diseases. There are many types of pathogens that generate common pathologies known to all, but fortunately, the prognosis of patients who contract them is always positive.