The West Nile Virus infection could be deadlier than previously thought, reports a recent study presented at the 2016 American Society of Tropical Medicine and Hygiene meeting.
The mosquito-borne disease is found to cause fatalities even years after initial exposure to the virus. Kristy O. Murray, the lead author of the study from the Baylor College of Medicine and Texas Children's Hospital said that, amid Zika virus threats prevailing in the United States, it was found that WNV is potentially fatal in people affected with the virus years after infection.
West Nile Virus Infection In United States
WNV infection that first appeared in the United States in 1999 infected around 45,000 people and claimed the lives of about 2,000 people accounting to four percent of fatality rate in the country. The WNV also belongs to the family of viruses that cause yellow fever and Zika. People infected with WNV do not experience any symptoms much similar to Zika infection.
However, in rare cases some people experience symptoms like fatigue, rash, fever and nausea. The complications of WNV infection include swelling of brain and spinal cord. Though WNV is known to be potentially fatal, no vaccine to prevent or treatment to contain the infection is found by far.
Study On West Nile Virus Infection
For the purpose of the study, Murray and her team studied 4,144 WNV cases reported in Texas between 2002 and 2012. The researchers reviewed acute fatalities that occurred in first 90 days of infection as well as deaths that were reported months and years after infection.
About 286 people were reported to have died of acute WNV infection and around 268 patients were found to have survived the disease. However, on deliberate analysis, it was found that all the patients that survived initial infection have died subsequently in upcoming months.
Outcomes Of West Nile Virus Infection
The overall deaths from WNV infection from both acute and delayed mortalities between 2002 and 2012 were found to be 554, which accounts to 13 percent of fatality rate in the country. The figure is much higher than four percent fatality rate between 1999 and 2015 reported by the U.S. Centers for Disease Control and Prevention.
In addition Murray found in a study in 2012 that among 139 patients infected with WNV about 40 percent of them developed kidney diseases. It is therefore clear that the WNV infection leads to chronic kidney diseases not only in elderly but also in patients under 60 years of age.
"We had been surprised in the 2012 study to see so much chronic kidney disease develop in younger West Nile patients because it's not that common in people under 60," Murray said.