By Robert Preidt
In the first study, Colorado State University researchers discovered that Aedes aegypti mosquitoes can carry Zika and chikungunya viruses at the same time, and can secrete high enough levels of both viruses in their saliva to potentially infect people with both in a single bite.
It's the first time this has been confirmed, the researchers said.
In the second study, researchers in northeastern Brazil identified severe neurological problems in patients treated during a rare and unprecedented simultaneous outbreak of Zika, chikungunya and dengue in 2015.
It was already known that Zika can cause Guillain-Barre syndrome, in which the immune system attacks nerve cells, causing paralysis and even death. But the researchers also saw this condition in patients who did not have Zika, but tested positive for either chikungunya or dengue.
The studies were to be presented Monday at the annual meeting of the American Society of Tropical Medicine and Hygiene in Atlanta. Research presented at meetings is considered preliminary until published in a peer-reviewed journal.
"Our analysis shows that each of these viruses may have the potential to cause a range of neurological complications, some very severe, and patients should be monitored for symptoms," Dr. Isadora Siqueira, an author on the second study, said in a society news release.
"What's very difficult to determine is whether having a co-infection with two of these viruses increases the risk of neurological problems. We are still looking closely at the case of the patient who was infected with both chikungunya and dengue," added Siqueira, who is a scientist with Brazil's Oswaldo Cruz Foundation.