The research means that the mixture of two lethal mosquito-borne illnesses, Zika and Chikungunya, can result in stroke
Stroke is a common cause of morbidity and mortality around the world. According to the American Stroke Association, stroke is a disease that affects the arteries that lead to and within the brain. It occurs when an artery that carries oxygen and nutrients to the brain is either blocked by a clot or ruptured. Because of this blockage or rupture, the brain does not receive enough oxygen and this leads to the death of the brain cells. Extremely severe strokes can lead to death.
Stroke and viral infections
According to a 2013 study published in the Journal of Stroke, stroke is a leading cause of death and disability in India with a high prevalence in both rural and urban areas. Another 2010 study on Infectious Diseases – Drug Targets found that while established risk factors such as diabetes, high blood pressure, high cholesterol, and obesity have been identified and are targets for stroke prevention, viral infections are also risk factors for stroke.
This study shows that the varicella zoster virus (VZV) that causes chickenpox and shingles, human immunodeficiency virus (HIV) and cytomegalovirus (CMV) can cause stroke as they penetrate directly into brain arteries and create clots, emboli and Cause blood vessel rupture.
A study published in JAMA Neurology in July 2020 linked patients with COVID-19 infection to high risk of ischemic stroke. This shows that the relationship between viral infections and the risk of stroke needs further investigation and the development of possible preventive measures and therapies is needed.
A new study published in The Lancet Neurology sheds further light on the fact that mosquito-borne viruses like Zika and Chikungunya can also cause strokes, greatly expanding the scope of study.
Zika, Chikungunya and the Risk of Stroke
The study begins by finding that arthropod-borne viruses, also known as arboviruses, are very common in tropical areas of the world. In countries like Brazil and India, outbreaks of malaria, dengue, chikungunya, and Zika occur almost simultaneously, suggesting that many of these viruses can infect those susceptible immediately. In Latin America, Zika and Chikungunya outbreaks have also been associated with an increase in immune-mediated and neurological diseases.
The researchers conducted an observational study between 2014 and 2016 that referred 1,410 adults aged 18 and over to Hospital da Restauracao, Brazil. These patients were suspected of having an acute neurological disease and a history of a suspected arboviral infection for the detection of a Zika, Chikungunya or Dengue infection by examining viral RNA or specific immunoglobulin M antibodies in their serum. Approximately 201 of these patients had symptoms related to arbovirus infection and were selected for further study.
Approximately 148 of these 201 patients had laboratory confirmed evidence of arboviral infection, with 98 patients showing evidence of a single infection. Of these 148 patients, 41 had zika, 55 had chikungunya, two had dengue fever, and 50 had signs of double infection: a fatal combination of zika and chikungunya. All arboviral patients had a wide range of central nervous system (CNS) and peripheral nervous system (PNS) disorders.
Chikungunya has been linked more often to CNS disorders such as myelitis (inflammation of the spinal cord, which can disrupt connections between the brain and the rest of the body). Zika infection was more likely to be linked to PNS disease, particularly Guillain-Barre syndrome (an autoimmune disease in which the immune system attacks healthy nerve cells and can ultimately lead to paralysis).
Patients with double Zika-Chikungunya infection and Guillain-Barre syndrome had a more aggressive disease and required intensive care and longer hospital stays compared to patients with monoinfections.
Eight of the total Zika-Chikungunya double-infected patients suffered strokes compared to five mono-infected patients with Zika or Chikungunya. This study therefore clearly shows that while Zika and Chikungunya are individually dangerous diseases that can increase the risk of stroke, that risk is much more severe in patients with a double infection of these arboviruses.
The researchers stressed that while the world’s attention is on COVID-19 and its neurological effects, the risks posed by the coexistence of other viral infections such as Zika and Chikungunya should not be ignored.
For more information, see our article on stroke.
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