Zika Virus Facts You Need to Know
How to Protect Yourself from Zika and Avoid Harmful Symptoms
Last month, Santa Barbara County sent doctors a report of two Zika virus infection cases discovered within our borders. The first was found in a pregnant woman. Since the Zika virus can cause birth defects, doctors are monitoring her closely. Both cases were in people who had traveled to an area where Zika virus has spread. Since I run a travel clinic and counsel people on preventing illnesses as they travel, I have studied a great deal about this new epidemic.
Zika is a virus. Viral infections are not like bacteria. The virus invades our cells and hides from the immune system. The virus then mixes its DNA with ours to take control of the cell and make more viruses.
Generally, a cell fills up with virus particles and breaks open. It then releases millions more of the same virus into our bloodstream to repeat the process with other cells. Since a virus uses our own cell mechanisms to replicate, there is little we can do to stop them. There are no “antibiotics” to kill them or to prevent a Zika infection. (Technically, they aren’t even living organisms since they have no independent metabolism or reproduction.)
There are some antiviral medications which inhibit the enzymes they force your cells to make. But these only slow the reproduction of the virus, rather than get rid of them. Currently, the most effective way to prevent Zika viral illness is with vaccines to build our immunity against them.
For these reason it is hard to stop a virus like Zika that is spread around the world. We have a very mobile society, where millions of people travel daily to foreign countries. Going around the world in only a few days is not uncommon, so people can bring back all sorts of infections. Moreover, being in cramped quarters on an airplane for many hours may multiply the risks.
The Zika Virus
Zika is a vector-borne virus, which means it is most often injected into the body of a victim by a mosquito. When a female mosquito feeds on the blood of a virus-infected person, she ingests millions of virus particles. If she then feeds on another person, her saliva injects the virus into the new victim and causes a Zika infection.
The Zika virus isn’t only found in the blood. It can be found in other body fluids, and is known to spread by sexual contact. There are also reports of infection by blood products. Zika has been found in blood donors in areas where the virus is endemic. Because many may have a mild form, or have no symptoms at all, the Zika virus can spread by people who don’t even know they are infected.
Symptoms of Zika are highly variable. While the majority of victims (four out of five) have no symptoms at all, a few get severe symptoms. Only one in five gets the typical symptoms of fever, joint pain, itchy rash, and bloodshot eyes. Serious Zika infection, or even death, generally only occurs in people debilitated in some other way from cancer, HIV, or genetic disorders.
Zika Virus Symptoms
Only about one in five people infected with Zika become ill. That means four out of five people infected with Zika exhibit no symptoms. If symptoms do occur, they are usually mild and last no more than a few days.
- Itchy rash
- Joint pain
- Muscle pain
- Bloodshot eyes
- Neurologic problems
One symptom of the Zika virus shows up in the nervous system. It causes inflammation of the white matter in the brain, similar to Multiple Sclerosis.
The known cases of Zika affecting the brain cause problems with:
- Motor function
In other words, it can affect many different functions of the brain. Guillán-Barré syndrome (GBS) seems to be the most common nervous system disorder. GBS is a progressive deterioration of the nervous system that gradually destroys the function of both sensory and motor nerves. Because it affects the protective coating around nerve conduction fibers, the longest nerves are the most affected. It usually starts in the feet and progresses up the body. In rare cases, people can die from GBS if it affects the muscles of respiration. GBS is thought to be an autoimmune disease triggered by an infection. Other infections, surgeries, and vaccinations, such as the flu vaccine, have also been known to cause GBS.
There have been only a few deaths for the millions of suspected cases of Zika virus around the world. The incidence rates of Zika cases in Brazil where the 2014-2015 epidemic supposedly began are as follows:
- About 200,000 suspected cases (most have no symptoms)
- 78,000 known cases
- 6 deaths
There has been one death associated with a Zika virus infection in the United States. A man in Utah traveled to an outbreak area and likely contracted the disease there. He had other health problems and the virus was discovered on post-mortem examination in July 2016. All cases of Zika in the United States, except for Puerto Rico and Florida, have been Zika travel related.
Zika pregnancy problems
Like most adults, pregnant women may have no symptoms. But the Zika virus definitely affects a fetus during development. Because the virus infects nerve tissue, it causes problems with the developing fetus’ brain.
In Brazil, where the outbreak started in 2014, a study from the public hospitals showed most of the babies with microcephaly (small head) had the Zika virus. None of the normal babies had the virus. Interestingly, 80% of the mothers with the affected babies had Zika. But 64% of the mothers with normal babies also tested positive for the virus. Therefore, it’s clear that not everyone who gets Zika infection during pregnancy will have birth defects.
Sadly, the list of problems in infants infected with Zika during pregnancy is getting longer. Of those pregnant women known to be infected with the virus, 29% were found to have abnormalities on ultrasound. New research is showing many different problems including:
- Short limbs
- Club foot
- Developmental delay
- Joint problems
- Seizure disorders
These types of problems are mostly related to the stages of development. Some of these won’t show up for months or years after birth. Thus, it could be that even a majority of fetuses are affected in some way by the virus. This is now one of the few viruses known to cause birth defects, and the research is still meager.
How Does the Zika Epidemic Happen?
The Zika virus was first discovered in the Zika forest in Uganda in 1947. It is related to a number of other diseases such as dengue fever, yellow fever, and West Nile Virus. For many years it was primarily located in tropical Africa and Asia, found mostly in monkeys, and occasionally humans. But between 2007 and 2013 it came to the Americas, probably Brazil, and started the epidemic of 2014-2015. Because the populations of that area had not been exposed to the virus, there was no immunity against it. As a result, the Zika virus spread rapidly and infected many people.
There is no vaccine, and no cure for the illness. There is only prevention or treatment for Zika symptoms once people get the disease. Clearly, prevention of infection is the best defense against Zika.
Protect Yourself from Zika
The virus is found in tropical and sub-tropical areas around the world. While the majority of cases come from mosquitos, there are now a significant number of cases known to have resulted from sexual contact. The virus is found in the body fluids of people with active infections, even when they have no symptoms. For this reason it can be spread unknowingly by people who travel, even if they avoid travel to Zika infected areas.
Preventing mosquito bites is the best way to avoid a primary Zika infection. There are a few preparations that will help. The mosquito that carries the virus is active during the day, but can bite during the night as well. If you are traveling to a tropical or sub-tropical area it is a good idea to use a mosquito repellant. The only two preparations that are known to actually prevent mosquito bites are equally as effective.