By now you have no doubt seen headlines about recent outbreaks of the mosquito-borne Zika virus in Central and South America. First identified in Uganda in 1947, the Zika virus has particularly devastating effects on children who are born to Zika-infected mothers. These children are often born with tragic birth defects such as microcephaly, blindness, deafness, and epilepsy.
Microcephaly is the most prevalent and ruinous, causing a baby’s brain to under develop during pregnancy or stop growing after birth, resulting in a smaller than normal head size and a lifetime of crippling physical and mental impairment.
Disease Knows No Border
As people move around, so does Zika. A few cases have started to crop up in the United States, mostly from international travelers. In an age of global travel, you may be wondering how the Zika virus could affect your community and what is being done to stop the spread.
Although many southern states and Puerto Rico could potentially suffer hundreds of thousands of Zika virus infections, an outbreak is unlikely to occur in or around Colorado.1
The primary type of mosquito that carries the virus is the Aedes aegypti, which can be identified by its distinctive white markings. The Ae. aegypti is usually found in tropical and subtropical regions, so the temperature, precipitation and humidity level in Colorado do not provide a suitable habitat.
There is growing evidence, however, that some Ae. aegypti populations are beginning to survive in temperate climates, such as Washington, DC.2 In a dry environment, Ae. aegypti eggs can be viable for over a year, enabling them to re-emerge after a cold winter. Other arboreal mosquito species with smaller populations can also transmit the Zika virus, so the definitive geographical reach of the disease is unknown.
The non-profit Public Library of Science (PLOS) recently published the results of their analysis on the possibility that Ae. aegypti mosquitoes could proliferate into more regions of the US. They found that while meteorological conditions are unsuitable for Ae. aegypti from December-March, conditions are suitable during peak summer months from July-September in 50 different major American cities, including Denver.
While the potential abundance of the disease-carrying mosquito in Denver is still low according to PLOS’ modeling, there is still the possibility that they could appear in the region.3
Colorado Cases
Mosquito bites are not the only way in which the Zika virus can be transmitted, and Colorado has the distinction of having the first known case of sexual transmission. In 2008, a Colorado State University professor researching malaria in Senegal unknowingly infected his wife after returning to the U.S. Although both ultimately recovered, the Centers for Disease Control and Prevention (CDC) have now added recommendations for safe sex to protect pregnant women from Zika.
Colorado mosquito control districts are well-versed in utilizing effective methods to combat other mosquito-borne diseases, such as the West Nile Virus, dog heartworm and Western Equine Encephalitis.
Animas Mosquito Control District (AMCD) has been trapping and identifying adult mosquitoes since 2004, and has identified 21 distinct mosquito species in their district. Madeline Geiger, an office and lab assistant at AMCD, reiterated that Ae. Aegypti and Ae. Albopitus, a suspected Zika carrier, have not been found locally thus far. However, AMCD points out mosquitoes can be transported via boat, car or aircraft, and it’s important to understand the impacts people may have on the migration of mosquitoes to other regions. This is especially true in the warmer months of the year andfor those who are returning from high-risk areas of the world.
The CDC has also determined that it is more efficient to detect cases in people rather than relying on mosquito-based surveillance, and thus recommends additional methods for the prevention of Zika transmission. This can be much more difficult than tracking West Nile, Ebola, and other serious diseases.
A person can be infected with the Zika virus and experience no symptoms at all, and those who do often exhibit seemingly minor symptoms such as fatigue, fever, chills or loss of appetite. In rare cases, a person may also experience rashes, headaches, eye redness, or vomiting. Even collectively, those symptoms could be the result of any number of other ailments, so being mindful of your health and your travel history is important when talking to your doctor.4
To further help control Zika, the Food and Drug Administration recently approved a 3-in-1 test to help identify Zika as well as two other exotic mosquito-borne illnesses: dengue fever and chikungunya. Neither of these is particularly deadly, but are easily spread and severe enough that serious outbreaks would present a public health emergency.
In addition to standard control measures such as source reduction (container elimination) and larvicide treatments prior to the mosquito season, the CDC reiterates the need for clear, timely communication between healthcare providers, local and state public health departments and vector control specialists.5
When formulating a clear best practices plan for disease communication, special districts should pay careful attention to potential areas of discrimination and lawsuits among employees. For example, an employee who travels to a Zika-affected area could be ostracized or discriminated against by other employees. Because it is the responsibility of the employer to protect employees from discrimination, special districts should consult their employment law counsel to ensure they are following proper procedures.
For more information about the Zika virus, visit cdc.gov/zika.
1 http://www.bbc.com/news/health-35690768
2 https://en.wikipedia.org/wiki/Aedes_aegypti#cite_note-12
4 http://www.cdc.gov/zika/symptoms/
5 http://www.cdc.gov/chikungunya/resources/vector-control.html
