It was early dawn, and the bogies had already scrambled to battle stations. They were orbiting their attack zone when the first victim entered their airspace. With laser precision, they launched the attack, securing their goal within seconds. A lone straggler suffered the ultimate loss; she was swatted and crushed by the human’s hand. Score 1 for the person and 52 for the mosquitoes!
All of us have been bitten by mosquitoes many times throughout our lives, and we’re all used to the little itchy bump that surfaces after the bite. But it goes away quickly and is really more of a nuisance than anything else. What can a few pesky mosquitoes actually do to a human?
Well, actually, quite a lot. Many millions of people around the world are affected by mosquito-borne infections such as malaria, yellow fever and dengue fever. And now there’s the concern you’ve been reading so much about in the papers: the Zika virus.
Zika virus was first discovered in Africa in the 1940s in the Zika Forest in Uganda. At first, it seemed that only monkeys had the virus, but in time, it started to infect humans. Eventually, it spread across Southeast Asia, the Pacific islands, Central America, and South America. It is transmitted person to person by several types of mosquitoes, from mother to child in utero, and from sexual contact.
Include fever, joint pain, rash, conjunctivitis, muscle pain, and headaches. One in five people who are infected with Zika will develop symptoms, which tend to be mild. People rarely die from this virus. It can take two to 14 days to show signs of infection, and once it surfaces, it can last one to two weeks. Children who get the infection don’t get different symptoms to adults. The unborn babies are the ones who have a high risk of problems. Once infected, you cannot get it again.
Since its discovery some 70+ years ago, Zika has been slowly spreading across the globe and is affecting more and more people every year. The news has picked up on it now because recently, the virus became associated with a condition called microcephaly (smaller than normal brain size) in a number of infants born to infected mothers in Brazil. Also, a type of temporary paralysis known as Guillain-Barré Syndrome has been associated with this infection. We have now documented many persons infected with Zika in the U.S. As I write this, all of them had acquired Zika while traveling outside the U.S. However, Puerto Rico, the U.S. Virgin Islands and American Samoa have reported mosquito-transmitted Zika.
As a result of this growing range of infection and potential for severe complications, several world health organizations, including the Centers for Disease Control (CDC), have issued warnings to travelers entering areas where they may become infected with Zika.
The Air Defense
At this time, there is no treatment or vaccine for Zika. Once someone gets the infection and shows symptoms, all we can do is provide that person with medication for fever control, fluids, and let them rest. Men who have had Zika infection can still transmit the infection up to a week after they have recovered from it. Pregnant women should contact their doctor immediately if they have recently traveled to areas where Zika is prevalent, or if they suspect they have Zika. The CDC has developed guidelines for testing for Zika. Also women who plan to get pregnant need to be aware of potential Zika exposure.
The best way to prevent getting Zika is to avoid exposure to the mosquitoes that carry it. Use mosquito repellant. There are many products that contain DEET; the higher level the better. Also, there are several non-DEET repellants that use permethrin (made from chrysanthemums). (Note: children under two months should not have mosquito repellant applied directly onto them.) Use clothes that cover most of your body (long sleeves and pant legs). Most mosquitoes are active at dawn and dusk, so avoiding outdoor activities during their active times also reduces exposure. And finally, eliminate any standing pools of water around your house. Mosquitoes need standing/stagnant water to breed. Several research groups are working on developing a vaccine against Zika. However, it may take several years to have an effective vaccine ready for use.
Unfortunately, Zika isn’t the only mosquito-transmitted infection we need to worry about. It has cousins like dengue fever, yellow fever, and the chikungunya virus. They all have similar symptoms, with dengue being very severe and yellow fever having a relatively high mortality rate. And then to add insult to injury, their distant cousin West Nile virus is also along for the ride.
We have had several large outbreaks of West Nile in the past few years. About 1 percent of those infected develop a neurologic infection and experience serious symptoms, with 10% of this group dying as a result of this infection. West Nile infects both birds and humans.
Last year, chikungunya (like dengue fever, but less severe) established a foothold in Florida in the mosquito population there. But most diagnosed infections were from travelers returning to the U.S. after visiting affected areas. I had a patient who recently returned from visiting family in El Salvador. She complained of severe headaches, fevers, joint pains, and a rash. We had her tested, and she was positive for chikungunya; fortunately, she fully recovered several weeks later.
I should also mention malaria. This is a parasitic, mosquito-transmitted infection that causes severe symptoms and cyclic fevers. The infection has infected and killed millions of people around the world. Luckily, we do have medications that can kill this infection, and there is a vaccine very close to completion for worldwide use. My practice routinely prescribes prophylactic medications to prevent infection when our patients travel to high-risk areas.
So far, we have not found any cases of mosquito transmission of Zika in the continental U.S. But the mosquitoes that transmit it live here in the U.S. as well. Since many people who get Zika infection don’t have any symptoms, it might already be spreading before we can know about it.
Zika is very similar to dengue, West Nile, and chikungunya in the symptoms that it causes, and it is related to the West Nile, dengue, and yellow fever viruses. They are all transmitted by infected mosquitoes. Zika is the “new kid on the block” and is showing that it can cause some serious problems. I recommend visiting cdc.gov for more in depth information on the Zika virus and its other related viruses. The vast majority of people infected with Zika will have either a very mild illness or no noticeable symptoms at all. But the potential complications are severe enough that it needs to be controlled and eliminated. If you suspect you have Zika or have been exposed to Zika, contact your doctor to be seen and evaluated.