A new study conducted with the participation of the Institute of Tropical Medicine (IMT) and Das Clínicas Hospital (HC), both from the USP School of Medicine (FMUSP), which identified two new cases of sabiá virus infection (SABV) in the country. 2019, strengthened the investigation into this cause of Brazil’s influenza. Previously, only four infections of this type were detected in the country, the last more than 20 years ago. The two infections were carried out in the middle of an outbreak of yellow fever in the southeastern part of the country.
“We did this research during the flu epidemic, so in cases where we could not diagnose it, we followed other viruses,” explains Dr. Ana Catharina Nastri, from the Department of Infectious Diseases at HC-FMUSP. “To our surprise, we found these two cases very rare.” According to him, advances in medical anatomy, especially in the electron microscope, allowed a more in-depth study of the Brazilian mammary virus, or sabiá virus, to bring new information about its clinical manifestations, histopathology and possible hospital infections. The results were published in an article in the journal Travel Medicine and Infectious Diseases, in May this year, by Drs. Nastri as the first author and guide from Professor Ana S. Levin, from the Department of Infectious and Parasitic Diseases at FMUSP.
The name pathogen refers to the suburb of Sabiá, located in Cotia municipality, Greater São Paulo, where the first victim is suspected of being infected. Although there are several types of Mammarena viruses described in different Latin American countries, SABV is a Brazilian character. “Some of these viruses have a well-known viral cycle, while our thrush viruses have very little data,” says a doctor. “We still do not know what its reserve is, how it is transmitted, and whether there would be an infection through human-to-human communication.”
Prior to the study, only four SABV infections had been recorded. Apparently, one of them took place in the city of Cotia, in 1990, and the other, in the city of Espírito Santo do Pinhal, in 1999, all located in the rural area of São Paulo State. In both cases, the infection affected rural workers who died from complications from hemorrhagic fever. Two other infections occurred in laboratory workers who became infected while handling the virus. Both survived.
Case A and B “
The two newly discovered cases, called “Case A and Case B” in a study conducted at Das Clínicas Hospital, occurred in the cities of Sorocaba and Assis (in the interior of São Paulo), respectively, and both patients were hospitalized in Das hospital. Clinical (HC) with diagnostic theory of severe cases of jaundice. The first was a 52-year-old man who had walked through a forest in the city of Eldorado (170 miles[170 km]south of São Paulo) and began experiencing symptoms such as muscle aches, abdominal pain, and dizziness. The next day, she contracted conjunctivitis, received medical attention at a local hospital, and was released. Four days later, he was hospitalized again with a high fever and drowsiness. Jaundice was suspected and he was transferred to Das Clínicas Hospital.
During his hospital stay, his condition worsened until he was transferred to the Intensive Care Unit (ICU), ten days after the onset of symptoms, with heavy bleeding, kidney failure, decreased consciousness and low blood pressure, and died. two days later.
Case B refers to a 63-year-old man, a rural worker from Assis (440 kilometers west of São Paulo), who developed fever, generalized myalgia, nausea and vomiting. The symptoms worsened and eight days later he was hospitalized with HC with severe depression and difficulty breathing and needed intubation. Poor left ventricular function (rapid decrease in cardiac function of the heart) resulted in refractory shock and death eventually 11 days after the onset of symptoms.
We know what and what is not yet known
To carry out the diagnosis, scientists used a metagenomic technique, which makes it possible to identify viruses that are not yet known through extraction, duplication and the final sequence of genetic material of an infectious agent. This material is then compared to other organisms in biological information databases, and information from pathogens from around the world. By linking the virus found in patients with other forms of Mammarenavirus and confirming the compatibility of the diagnosis with clinical practice, it was identified as SABV.
In the analysis of the two malignant tumors of the study, the researchers found symptoms similar to those registered in 90-year cases. Ana Nastri. In all cases, there was severe damage to the liver and organs associated with the production of immune cells, which could facilitate the emergence of secondary infections, making the initial diagnosis more difficult.
Regarding the geography of the infection, the four registered cases had a common infection that occurred in rural areas. “We speculated, based on other Mammarena viruses in South America, that the person was probably contaminated by inhaling viral particles, probably from rat feces. But this has not been proven accurate because we have very few cases reported,” says Ana. The doctor also warns that, especially because they are rural areas with limited laboratory and diagnostic resources, some cases may have eluded medical analysis, making it difficult to have a comprehensive summary of Brazilian hemorrhagic fever. “We don’t know if there really is no worse case, like jaundice, which is among the most severe cases to those who have no symptoms at all.”
An important difference in research related to previous viral reports is the incidence of hospital infections. Scientists at IMT and Das Clínicas Hospital did not find any such infections during the follow-up communication. “This shows that with the usual precautions, such as helmets, gloves, glasses and aprons, there was no infection, and it makes us calm about the virus,” says Ana Nastri. He points out, however, that it is still impossible to reach a conclusion, since these are just two cases.