In August of 1998 my oldest child was born in Washington, D.C. I spent many hours strolling him around the Capital Crescent Trail during his first months. Two years later, in the hot and humid August of 2000, my second child was born. We spent the first few months of her life avoiding the outdoors.

The difference? West Nile Virus.

In the summer of 1999, the West Nile Virus made its way through customs and set up permanent residence in the U.S. West Nile is carried by a large number of mosquito species, including Aedis aegypti, the Yellow Fever Mosquito. The presence of West Nile moved the mosquito from the realm of mere nuisance in the public mind. Our bond with DEET fluorished.

There have been several mosquito-borne viruses in the U.S. that cause encephalitis, but their impact on people is relatively small. They’ve been of interest primarily to epidemiologists and those few unfortunates who have been affected by them.

We weren’t always so lackadaisical about mosquitoes. Malaria and yellow fever used to be real threats in this country. In the late 1700’s, yellow fever killed thousands in East Coast port cities. It was mostly controlled in the U.S. after civic efforts addressed the conditions that promoted disease spread. But Aedes aegypti, the yellow fever mosquito, remained.

In the 20th century massive mosquito eradication efforts in the Americas led to a dramatic decrease in the Aedes aegypti population. But in recent decades these programs have not been maintained, as today the range of habitation for the mosquito is increasing. The failed eradication is a prime example of the importance of a strong public health function with regard to infectious disease, if only for its economic benefits. Aedis aegypti now lives in 23 states in the U.S., primarily across the south.

Aedes aegypti is not the only carrier of West Nile Virus, so even if we were to eradicate the mosquito, West Nile would remain.

However, two more recent threats to the U.S. are only carried by Aedes aegypti, making it a concern in the medical community once again.

Dengue Fever is also known as break-bone fever, because of the severe muscle and joint pain it causes. The symptoms of this disease range from none at all to the full-blown Dengue hemorrhagic fever, which is as awful as it sounds.

Most cases of Dengue fever in the U.S. are the result of travel to areas where it is more common. However, there have been local outbreaks in Texas and Hawaii.

The second concern is Chikungunya, which causes fever, joint and muscle pain, headache, and rash. It is rarely fatal, but it can lead to chronic arthritis.

Chikungunya is a new disease to the Western Hemisphere, with cases reported only in travelers until 2013.  The first case of locally transmitted Chikungunya was reported in the Caribbean that year, and in the short time since it has become one of the major mosquito borne infections in the West, with over 1.3 million cases reported as of April 2015. Local transmission has been limited in the U.S. because, so far, we only have the strain transmitted by Aedes aegypti.

Clearly, it is in our best interests to stop the growth of the Aedes aegypti’s geographical range. Local authorities must take the lead in mosquito eradication, and individuals must be responsible for their environments. By removing standing water sources that serve as breeding grounds for mosquitoes and using long sleeves and mosquito repellants to prevent bites, we are all taking the necessary steps to prevent these diseases – in ourselves and our communities.

Finally, if you become ill after traveling to an area where these diseases are endemic, be sure to discuss this with your doctor. He can provide appropriate treatment and advise you on how to prevent spread to those around you.

With rising travel and increasing populations, our encounters with diseases like Dengue and Chikungunya are sure to increase. It is our response to them that will determine whether they are a nuisance or our nemesis.