March 23, 2016
The Aedes aegypti mosquito, which carries the Zika virus, isn’t likely to find a hospitable home in the Philadelphia region anytime soon, according to Claude Krummenacher, a professor of biomedicine and biology at Rowan University.
That’s a good thing since Aedes aegypti kills more people than any other vector species on earth, Krummenacher said Wednesday.
But those deaths are not due to Zika, which has devastating effects on fetal development but results in only mild symptoms on adult humans.
Aedes aegypti is the mosquito that also carries Yellow Fever, Dengue Fever and West Nile virus. Together those diseases kill millions of humans around the world, the professor said during a lecture.
And while researchers are at work on a Zika vaccine, nothing is on the immediate horizon, Krummenacher said.
He pointed out that years of research and lots of money have failed to develop an effective vaccine for Dengue fever.
Another worry is that a different mosquito species, the Asian tiger mosquito, could eventually become a carrier of the Zika disease.
The tiger mosquito, though not native to the mid-Atlantic, is present here already. E. aegypti can not survive in New Jersey – though climate change might expand its habitat into the region in the future, according to the professor.
His presentation, “Explaining the rise and spread of the Zika virus: A new pandemic?” was part of the Hollybush Symposium at Rowan. Graduate student Rosanna Dent also presented.
The professor went over the history of the virus, from its discovery in the Zika forest of Uganda in 1947 in monkeys, its first appearance in humans in 1952 and its explosion when the Asian strain of the virus arrived in Brazil – and spread.
He said current estimates put Zika infections at three to four million between 2015 to 2016, and the virus is present in more than 20 countries.
To date, all of the cases in the continental United States are travel-related, with patients having contracted the disease while abroad.
However, the virus is present in U.S. territories, like Puerto Rico and the Virgin Islands. There are 280 cases in U.S. territories, the professor said.
But Krummenacher said that the true number is likely far larger.
That’s because 80 percent of those who get the virus show no symptoms and symptoms are usually mild in those who do present symptoms, thus going unreported.
Symptoms include pink eye, fever, headache, skin rashes and joint pain.
The main threat is a prenatal developmental problem known as microcephaly.
Children with that issue are subject to seizure, developmental delay, intellectual disability, movement and balance issues, swallowing difficulties, hearing loss and vision problems.
One fact in favor of containing the virus is that the carrier mosquitos only live about two weeks in the wild and the virus takes seven to 10 days to develop in the bug’s gut and then to travel to its saliva, where it can be passed to humans.
There are cases of the disease having been sexually transmitted to women by men, but not vice versa, said the professor.
Transmission via oral sex and man-to-man have not been confirmed. There are no reported cases of blood or saliva carrying the virus from human-to-human, said the professor.
So far, the release of genetically modified, sterile, male carrier mosquitos has shown the greatest promise in knocking down Aedes aegypti. The sterile males would compete with the fertile males to breed, however no offspring would be produced.
Populations dropped by 82 percent where sterile mosquitos were released.
But releasing genetically modified mosquitos is controversial, he added.