A deadly combination of two mosquito-borne viruses can trigger a stroke, new research published in The Lancet Neurology has shown.
Researchers from the University of Liverpool and Brazilian staff investigated the link between neurological diseases and infections with the Zika and Chikungunya viruses. These viruses, which are mainly found in the tropics, cause large outbreaks of rash and fever in countries like Brazil and India. It is common knowledge that Zika causes brain damage in babies who are infected during pregnancy. However, the new research shows that it can cause nervous system disorders in adults too.
The study of 201 adults with emerging neurological disease treated in Brazil during the 2015Zika and 2016 Chikungunya epidemics is the largest of its kind to describe the neurological characteristics of infection for multiple arboviruses circulating simultaneously.
The new research shows that any virus can cause a range of neurological problems. Zika is particularly likely to cause Guillain-Barre syndrome, in which the nerves in the arms and legs are damaged. Chikungunya was more likely to cause inflammation and swelling in the brain (encephalitis) and spinal cord (myelitis). However, it was more likely that a stroke that could be caused by either virus alone would occur in patients who were infected with the two viruses together.
A stroke occurs when one of the arteries that supply blood to the brain becomes blocked. The risk of stroke is known to increase after some types of viral infections such as the varicella zoster virus, which causes chickenpox and shingles, and HIV. Stroke is also increasingly recognized as a complication of COVID-19. This has important implications for the screening and treatment of patients with viral infection, as well as for understanding the mechanisms underlying the disease.
A total of 1,410 patients were examined at the Hospital da Restauração in Recife, Brazil over a period of two years and 201 were recruited. Extensive PCR and antibody tests for viruses were carried out in the Fiocruz laboratories.
Of the 201 patients suspected of having a neurological disease related to Zika, Chikungunya, or both, 148 had confirmation of infection on laboratory tests, of which about a third had infection with more than one virus.
The mean age of the patients was 48 years and just over half of the patients were female. Only about 10% of patients had fully recovered on discharge, and many had persistent problems such as weakness, seizures, and problems with brain function.
Of the stroke patients, who were on average 67 years old, around two-thirds had an infection with more than one virus. Many of the people who have had a stroke have had other stroke risk factors, such as: B. High blood pressure, which indicates that stroke after Zika and Chikungunya virus infection is most common in people who are already at high risk.
Dr. Maria Lúcia Brito Ferreira, neurologist and department head at Hospital da Restauração, head of the Brazilian team, said: “Zika infection most commonly causes rash and fever syndrome without many long-term consequences, but these neurological complications, although rare – can Requiring intensive care in the hospital, often disabling and fatal. “
Dr. Suzannah Lant, a Clinical Associate at the University of Liverpool who worked on the study, said, “Our study highlights the potential effects of viral infection on the brain with complications such as stroke. This is relevant to Zika and Chikungunya, but also to our understanding other viruses such as COVID-19, which is increasingly associated with neurological complications. “
Senior author Professor Tom Solomon, director of the research division of the National Institute for Health Research for Health Protection in Emerging and Zoonotic Infections at the University of Liverpool, said: “Although the world’s attention is currently on COVID-19, other viruses are the recently emerged, such as Als Zika and Chikungunya, they keep circulating and causing problems. We need to understand more about why some viruses cause stroke so we can try to prevent it in the future. “
The researchers are supported by grants from FACEPE, ZikaPLAN (as part of EU Horizon 2020), the Medical Research Council, Wellcome Trust, and the National Institute for Health Research.