Mosquitoes can pick up and transmit Zika and chikungunya simultaneously – Study

MalariaMosquitoes can pick up and transmit Zika and chikungunya simultaneously, a new study has found.

The study was presented at the 2016 Annual Meeting of the American Society of Tropical Medicine and Hygiene (ASTMH).

A press release copied to, states that mosquitoes are capable of carrying Zika and chikungunya viruses simultaneously and can secrete enough in their saliva to potentially infect humans with both viruses in a single bite.

The release notes that scientists are investigating whether antibodies to dengue can either intensify or, conversely, neutralize a Zika virus infection. Zika and dengue are closely related and come from the same family of viruses, known as flaviviruses. Very little is however, known about Zika’s possible interactions with chikungunya in humans or mosquitoes.

Currently, researchers at a laboratory headed by Greg Ebel, ScD, at Colorado State University, are testing what happens in the Aedes variety of mosquitoes responsible for transmitting the viruses when they encounter more than one virus at a time. In a contained experiment, the scientists allowed mosquitoes to feed on blood that contained dengue, chikungunya or Zika, either alone or in combination. The tests so far show strong evidence that mosquitoes can pick up and transmit Zika and chikungunya simultaneously—something that had not been confirmed before, given the recent arrival of Zika in the Americas, the release explained.

The release also noted that it is not clear if mosquitoes can carry all three viruses at the same time. But a a previous  study, also conducted in a laboratory setting, found that Aedes mosquitoes can carry dengue and chikungunya simultaneously, an observation that was confirmed by the Colorado State research team. And the real-world opportunities for mosquitoes to encounter more than one of these viruses appear to be increasing.

The release further said a recent study in Nicaragua showed that about one in five patients who tested positive for dengue, chikungunya or Zika also had a co-infection with at least one of the other two diseases. Some even tested positive for all three.

“We need to understand more about what happens in both mosquitoes and people when all of these viruses are circulating in close proximity,” Dr. Claudia Rückert, who  presented the results at the ASTMH meeting was cited as saying in the release.

“The  study also suggests that co-infection with chikungunya inhibits infection of Zika virus in the Aedes aegypti mosquito, meaning that one virus may outcompete another in mosquitoes, which could have an impact on the epidemiology of two mosquito-borne viruses circulating at the same time,” she added.

It mentioned that a second study presented at the meeting, by researchers in Brazil showed new insights from their efforts to work in real-time to untangle a web of neurological complications encountered in a group of 21 patients at the Roberto Santos General Hospital in the northeastern city of Salvador-Bahia over a four-month period in 2015 during an “unprecedented and concurrent” outbreak of Zika, dengue and chikungunya.

Dr. Isadora Siqueira, a scientist with Brazil’s Oswaldo Cruz Foundation was quoted as saying “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.”

“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,” she added.

Zika is already known to occasionally cause Guillain-Barré Syndrome (GBS), which prompts the immune system to attack nerve cells, and can cause paralysis and even death. But Dr. Siqueira said they also saw GBS in patients who did not have Zika — but tested positive for either chikungunya or dengue.

By Pamela Ofori-Boateng
Copyright © 2016 by Creative Imaginations Publicity
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