Mosquito-borne Disease & the Zika Virus

Ah yes the good with the bad! South Carolina, especially the Lowcountry, is often described as a wondrously beautiful land. This is naturally true; however, with this natural beauty and inviting climate comes our dreaded co-inhabitant, the mosquito. To be exact, South Carolina and a few neighboring states are home to the Aedes aegypti mosquito which is the mosquito that has grabbed our attention because it spreads the Zika Virus. (More on that later.)

What are Some Common Mosquito-Borne Diseases?

Mosquitoes are known to inflict diseases on nearly 700 million humans annually worldwide. That is a lot of diseases caused by the tiny biting insect. The diseases are caused by bacteria, viruses, or parasites, meaning that mosquitoes are quite good at carrying a wide variety of bad things and infecting us humans with a simple, usually painless bite. Some of the diseases strike fear in us by just mentioning their names, for example, malaria, dengue fever, West Nile virus, yellow fever, equine encephalitis, and now the newest one, Zika fever. Some of these diseases kill an estimated one million people each year and cause pain and suffering to countless others. In other words, mosquito-borne illness is a major health problem.

The Mosquito Bite

Everyone who lives in our part of the world and in Africa and in North and South America is a target for the various mosquitoes who need our blood for their preservation. 

Ordinarily a mosquito bite is innocuous and especially in this country, but in some people an allergic reaction develops so that a bite can become a source of pain, itching, and if scratched a source of bacterial infection. Some people, including this writer, can become desensitized so that there is little or no local reaction to the bite. However, the local symptoms at the site of the bite have no relation to whether one is infected with one of the diseases that mosquitoes carry. Thus, the actual bite reaction does not indicate whether one is infected with a disease. As of this writing, in our region there are no serious mosquito-borne diseases, although previously yellow fever and malaria were common in coastal South Carolina.

The Zika Virus

There has been a great deal of publicity about the Zika virus that has now been tabbed by the World Health Agency (WHO) “an international health emergency.”  There are two reasons for this: 1) the virus originally found in Africa (the Zika forest, to be exact) has now become common (around a million cases) in South America and spread to parts of Central America; and 2) the disease has been linked to a devastating birth defect called microcephaly (small head and abnormal mental function). Pregnant women are subject to delivering abnormal babies. Men have developed Guillain-Barre, another life threatening neurological disease based on the patients own immune system attacking his/her nerves. Thus the Zika virus can be a very bad actor and is threatening to disrupt the Olympic Games in Brazil. The virus is usually spread by the infected mosquito biting an infected person and taking the virus to the next victim. However, the virus has been spread by sexual contact, blood transfusion, and mother to infant at birth.

Symptoms & Diagnosis of Zika Disease

The symptoms of Zika disease are non-specific and occur in only about 20% of people known to be infected. Yes, that is correct, 80% of people infected with the virus never know they were infected. The classic symptoms are “flu-like:” fever, itchy rashes, muscle and joint aches, headaches, fatigue, and red eyes. These symptoms occur 2 to 7 days after infection. The diagnosis is made after eliciting a history of travel in an affected region (please refer to the latest CDC advisory regarding travel.)  A tell-tale rash may be present and a blood test is a specific diagnostic test to prove the presence of the disease.

Treatment

There is no specific treatment for Zika viral disease. There is no immunization against it. There is no way to prevent the damage it rarely causes to unborn babies and rarely in causing Guillain-Barre Disease. However, in the 20% of those presenting with symptoms the treatment is rest, fluids, and acetaminophen (do not take aspirin, naproxen, or ibuprofen) for headaches and fever.

Prevention of Zika & Prevention of Mosquito Bites

The Aedes mosquito (found in coastal South Carolina) spreads the disease in infected regions, but not here, at least not now. However, it is good to get in the habit of preventing mosquito bites by doing the following things:

• Stay indoors when they are biting (morning and  late  afternoon)
• Cover your skin with loose fitting, light colored clothing
• Use insect repellent when outside
• Eliminate standing water where they breed
• Use DEET-based repellent on clothing

At present (March 2016) there have been 193 cases of Zika diagnosed in the United States: all cases have been acquired outside the continental U.S. and none have been mosquito-borne in this country. However, some feel it is only a matter of time until the disease does invade the U.S. and becomes transmitted by our very own mosquitoes.

The Bottom Line

As the world shrinks and travel increases, new diseases make the trip along with business people and tourists. Healthy aging requires that we watch for possible diseases not yet in our backyard, where our mosquitoes are just waiting to help spread them.