Spotted fever: understand how the disease can kill – 06/14/2023 – Health

Spotted fever, a disease that recently caused the death of at least three people in the interior of São Paulo, is caused by the bacteria rickettsia, which has different species around the world. In Brazil, there are two that cause the disease: Rickettsia rickettsiiassociated with more severe conditions, and Rickettsia parkeriwhich usually does not cause very serious complications.

Recent deaths were caused by Rickettsia rickettsii. This bacteria is mainly transmitted by ticks found in rural areas or along riverbanks. In São Paulo, the most common is the star tick.

In the most severe cases of Rocky Mountain spotted fever, the bacteria destroy blood vessel cells, which can cause kidney failure, seizures, coma and multiple organ failure.

Elba Lemos, physician and researcher at the laboratory of hantaviruses and rickettsiosis at Instituto Oswaldo Cruz (IOC/Fiocruz), explains that the tick, once on someone’s body, inserts its mouthparts into the person’s skin to suck the individual’s blood, activating the development of salivary gland cells.

If the tick is infected, the bacteria rickettsia is inside these cells. That is, when the development of these cells is activated, the same happens with bacteria. After that, the tick spits out the saliva and transmits the bacteria to the human.

Between the start of saliva production and the insertion of the substance into the person’s body, there is an interval of about four to six hours. Therefore, quickly removing the tick from the skin is a way to mitigate the risks of infection.

Inside the human body, the microorganism needs to enter a cell to develop — a type of bacteria known as obligate intracellular bacteria. In humans, the cells that rickettsia penetrates are the endothelial cells, which make up the inner part of blood vessels.

Inserted into these parts of the human body, the pathogen thrives. “A rickettsia goes into the vase [sanguíneo]multiplies and begins to destroy the vessel wall”, explains Lemos.

If there is no immediate treatment, the bacteria erodes these vessels, and various symptoms appear. At first, fever, headache, diarrhea, nausea and malaise appear. Another common manifestation is spots on the body.

“The patient will be swollen because the liquid leaks [dos vasos, que ficam com as paredes comprometidas]. You will not urinate anymore, you will have kidney failure”, says Lemos. The doctor also says that there is multiple organ failure and the person can suffer from coma and convulsions, in addition to other manifestations. And then comes death.

But if there is treatment with antibiotics, the bacteria dies and the patient survives. This intervention needs to be done as soon as possible. If treatment starts only from the 7th to the 10th day after the onset of symptoms, the chances of survival are practically zero.

Therefore, the sooner you start applying the drugs —with medical supervision—, the better. This should occur even without laboratory confirmation of the diagnosis. If you wait for the tests, in addition to the possibility of a false negative, it may be too late for the person to leave alive.

“It’s a disease that, if you treat it at the right time, the patient will be cured”, says Lemos.

Emy Gouveia, infectologist at the Einstein, also cites the importance of antibiotics and mentions some support measures, such as hydration and fever control, which can be adopted.

“Some patients will need support in intensive care units. Therefore, it is important that individuals look for the health service if signs and symptoms develop after a tick bite”, he recommends.