Researchers at the University of São Paulo deepen their investigations into the sabiá virus (SABV), which causes Brazilian hemorrhagic fever.
The studies conducted by the Instituto de Medicina Tropical (IMT) and Hospital das Clínicas, both from the Faculty of Medicine of USP, are carried out based on the diagnosis of two cases of infection in 2019.
Previously, only four such infections had been detected in the country, the last one more than 20 years ago. The two most recent diagnoses were made amid an outbreak of yellow fever in the Southeast region.
“We did this study during the yellow fever epidemic, so in cases where we were unable to make the diagnosis, we went after other viruses. To our surprise, we found these two cases to be extremely rare,” said Dr Ana Catharina Nastri, from the Division of Infectious Diseases at Hospital das Clínicas, in a statement.
According to the researcher, first author of the study supervised by Professor Ana S. Levin, from the Department of Infectious and Parasitic Diseases, advances in the area of disease investigation, especially in electronic microscopy, have allowed a more in-depth study of the sabiá virus (Brazillian mammarenavirus).
New information on clinical manifestations, tissue and organ tests and the possibility of hospital transmission were published in the journal Travel Medicine and Infectious Disease.
new cases
The two new cases detected occurred in the cities of Sorocaba and Assis, in the interior of São Paulo. Patients were treated at Hospital das Clínicas with suspected serious case of yellow fever.
The first was a 52-year-old man who had walked through the forest in the city of Eldorado (170 kilometers south of São Paulo) and began to experience symptoms such as muscle pain, abdominal pain and dizziness.
The next day, he developed conjunctivitis, being medicated at a local hospital and then released. Four days later, he was hospitalized again with a high fever and drowsiness. Yellow fever was suspected and he was transferred to Hospital das Clínicas.
During hospitalization, the clinical picture worsened until he was transferred to the Intensive Care Unit (ICU), ten days after the onset of symptoms, with significant bleeding, renal failure, lowered level of consciousness and hypotension, two of whom died. days later.
The second case is a 63-year-old man, a rural worker from Assis (440 kilometers west of São Paulo), who presented with fever, body pain, nausea and prostration. The symptoms worsened and eight days later he was admitted to the HC with a drop in consciousness and respiratory failure requiring intubation. A malfunction in the heart led to shock and death 11 days after the onset of symptoms.
What the analyzes show
The diagnosis of infection was performed using a technique that involves sequencing the viral genetic material. In analyzing the two infections, the researchers identified symptoms analogous to those recorded in the cases of the 1990s.
“The clinical part is very similar to what we had seen before and, between the two new cases, the manifestation was also very similar”, says Ana.
The study indicates that in all cases there was a significant impairment of the liver and organs associated with the production of defense cells, which may have facilitated the emergence of secondary infections, making the initial diagnosis more complex.
The registered cases had as a common point infections that occurred in rural areas. “We inferred, based on the other Mammarenaviruses in South America, that the person is likely to be infected by inhaling viral particles, perhaps from rodent feces. But this has not been proven precisely because we have very few cases described”, says Ana.
The doctor also warns that, precisely because they are rural areas with fewer laboratory and diagnostic resources, some cases may not have been identified, making it difficult to have a complete overview of Brazilian hemorrhagic fever.
Scientists found no hospital-transmitted infections during contact tracing.
“This shows that with the usual precautions, such as a mask, glove, glasses and apron, there was no transmission, and it makes us a little calmer about our virus”, says Ana. She emphasizes, however, that it is not yet possible to establish a conclusion, due to the limitation of the cases evaluated.
About the sabiá virus
The name of the virus refers to the Sabiá neighborhood, located in the municipality of Cotia, in Greater São Paulo, where the first victim is suspected to have been infected.
Although there are several types of Mammarenavirus described in different countries in South America, the sabiá virus is characteristic of Brazil.
“Some of these viruses have the most well-known viral cycle, while our thrush virus has very little data. We still don’t know what its reservoir is in nature, how it is transmitted, and whether there would be infection through human-to-human contact,” says the doctor.
Prior to the study, only four SABV infections had been recorded in the country. The researchers estimate that one of them took place in the city of Cotia, in 1990, and another, in the city of Espírito Santo do Pinhal, in 1999, both located in the rural area of the state of São Paulo.
In both cases, the disease affected rural workers who died due to complications from hemorrhagic fever. The other two infections, which did not progress to death, occurred in laboratory workers who may have been infected while handling the virus.
(With information from the USP Journal)
Source: CNN Brasil
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