Spotted fever: ‘Environmental interference favors this and other diseases’

Doctor explains that deforestation contributes to the migration of animals, which are often reservoirs of viruses, bacteria and other microorganisms

In 1982, the then resident of Social Medicine at the Federal University of Minas (UFMG) Marcio Antonio Moreira Galvao he left for Grão Mogol, a city in the north of the state, to help investigate a mysterious epidemic that had killed eight people up to that point. Typhoid fever, a bacterial disease transmitted by contaminated water and food, was initially suspected.

“But the only patient who survived took chloramphenicol,” he says, referring to one of the antibiotics used to fight Rocky Mountain spotted fever, which is transmitted by the bite of ticks contaminated with such bacteria. rickettsia.

Then attention turned to this possibility, later confirmed by tests. All cases that arose subsequently were treated successfully.

Subsequently, Galvão directed his professional career towards the subject, specializing in the epidemiology of Rocky Mountain Spotted Fever and so-called rickettsiosis and in accidents caused by venomous animals.

According to him, one of the reasons for seeing the return of worrying disease outbreaks is related to human interference in the environment. After all, many animals, which are often reservoirs of viruses, bacteria and other microorganisms, end up losing their natural habitats and getting ever closer to big cities.

OR Stadium spoke to the doctor, who is a retired professor at the Federal University of Ouro Preto (UFOP), about the recent cases of Rocky Mountain Spotted Fever in rural Campinasin Sao Paulo.

Is the situation observed in the region of Fazenda Santa Margarida, in the district of Joaquim Egídio, in Campinas, outside the curve or within the norm regarding the epidemiology of spotted fever?

Every time we have an outbreak of spotted fever, I think it causes confusion because, in general, it affects healthy people of different age groups.

But what has attracted attention in this specific region of São Paulo is the high lethality rate, i.e. the number of deaths in relation to the number of confirmed cases so far.

Therefore, in this locality, i.e. around the Fazenda Santa Margarida, the situation is off the curve, considering what we have seen in the State of São Paulo as a whole.

It is worth mentioning that the states with the highest number of cases are Minas Gerais and São Paulo.

And what can explain this high mortality rate?

The first point is that São Paulo has a good disease surveillance system. [então, os casos são de fato registrados].

A second reason is that we always suspect that the bacterial strain circulating in São Paulo may be more powerful, more virulent.

You see: the bacteria that cause the disease are the same [Rickettsia rickettsii]but there are different strains and degrees of virulence.

It would be necessary to collect ticks to understand which strain is in that region and what is happening there.

What is the role of the capybaras in this story?

They are amplifiers of the problem, because they can carry ticks of the species on their bodies. Amblyomma sculptum AND Amblyomma doubt, capable of transmitting Rocky Mountain spotted fever when contaminated by pathogenic bacteria of the genus Rickettsias.

In the Pantanal they roam in groups of 25, 30 animals. Here are flocks of 60 or more capybaras.

It is important to do a large environmental study and think about the management of these animals, especially in areas with an excess of capybaras. But we cannot lose sight of the fact that the animal is not to blame.

The main culprits are the vector of the disease, i.e. the tick, and man, who has attacked the environment.

We’ve seen many individual guidelines for avoiding the disease, such as putting your pants inside your boots when walking in risk areas. Are these measures able to stop the epidemic?

These are important attitudes, but by themselves they do not resolve the issue. It is useless to put a sign in the epidemic zone and ask to beware of capybaras.

My concern is with what’s on the ground, on the ground. I think it’s important to have a quarantine in this area, to cancel events there. And then evaluate the animals, the pasture, the vegetation…

Carefully study the characteristics of this outbreak.

Furthermore, it is essential to disseminate these events to the population and inform doctors about the disease. If you suspect the condition, according to patient reports, you need to treat it quickly.

Many doctors do not know the disease and do not know what to do because, for almost 40 years, there has been an epidemiological silence and the situation has been little publicized.

And what happened to make this type of disease become a concern again?

Especially since 1980, deforestation has occurred at a faster rate, resulting in the migration of reservoir animals to other areas.

These animals, previously more isolated, began to approach cities and people.

Everything suggests that small rodents (such as rats) played a role in maintaining Rocky Mountain spotted fever outbreaks, and then large rodents went down in history, such as capybaras, taking the disease in new directions.

And these capybaras run away from humans. So, during the day, they don’t show up much. They go to the fields at night, in herds. Therefore, it makes no sense to go to an event and think: “I don’t see a capybara here, there is no danger.” It is at night that they circulate.

Can interference with the environment continue to contribute to the onset of such worrying diseases?

For sure. Today I’m in Mariana (MG). And, in 2017, we had a yellow fever outbreak that was never seen here before. And everything indicates that it was motivated by the breaking of the Fundão dam.

It is necessary to understand that ecological changes can cause animals to die or migrate, facilitating the emergence of diseases in humans.

If we continue irresponsibly to modify the environment, leading to environmental disasters, we run the risk of facing outbreaks of yellow fever, Rocky Mountain spotted fever, leptospirosis, among other diseases.

In the case of Rocky Mountain Spotted Fever, what is the role of seasonality in the spread of the disease?

The life cycle of the tick matters. From May it is in an intermediate phase, called nymph, in which it is neither larva nor adult. It is at this time that Rocky Mountain spotted fever is transmitted the most. This goes on more or less until September and October. It is the most critical period to contract the disease in Brazil.

Then, starting in October, it becomes an adult and the sting is stronger. With this, the person can feel the presence of the tick and can quickly remove it from the skin. Often this prevents the occurrence of the disease, since the tick does not have time to transmit the bacteria.

Source: Terra

Ben

Ben Stock is a lifestyle journalist and author at Gossipify. He writes about topics such as health, wellness, travel, food and home decor. He provides practical advice and inspiration to improve well-being, keeps readers up to date with latest lifestyle news and trends, known for his engaging writing style, in-depth analysis and unique perspectives.