by Heather Roncinske
Zika virus and the mosquito responsible
In recent years we have all heard about the “new” mosquito-borne virus, “Zika.” This virus has been spread through the mainstream media and pretty much everywhere online all with contradicting information…leading to more confusion and fear than anything else.
Zika virus is not new and was actually first identified in 1947 in Uganda in rhesus monkeys. It was subsequently identified in humans in 1952 in Uganda and Tanzania. Since, it’s first human case it has made its way throughout Africa and into Asia. 1966 the first case found in South East Asia, in Malaysia. 1968 a dozen cases confirmed in Nigeria. In the late 1970’s cases documented in Pakistan, India, Malaysia and Indonesia. In 2007 the first major outbreak reported on island of Yap in Micronesia with 200 people affected. In 2013 an outbreak of 35,000 cases in French Polynesia, with cases leading to Guillain-Barre syndrome and Microcephaly. It was not until 2014 when the virus spread to Brazil causing alarm a year later when the country recorded nearly 4,000 cases of microcephaly that may be linked to Zika. In 2016 Cases were recorded in Columbia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Mexico, Panama, Paraguay, Venezuela, Puerto Rico and the United States.
I am sure you are curious to know why this has not been followed more closely since it was first discovered in 1947? Zika at first was in most cases only seen as causing mild like flu symptoms in humans; at the time the link between microcephaly was not made due in part to the small amount of cases reported. In non-pregnant adults little major risk was identified. Only 1:4 people whom contract Zika get symptoms of any kind. Symptoms range from fever, rash, joint pains and last from a few days to a week have been the most common and no long term complications were usually found. Severe complications were reported, however very rare. Most common of the severe complications were Guillain-Barre syndrome, many infections can cause this and less than 1:1000 people get it with the Zika virus. Peripheral nerves have been affected due to an auto-immune response to the virus, causing tingling and numbness in the legs. It can lead to paralysis, but only 1/3rd of the cases have seen this. There have also been some cases that have needed respiratory support, but in most of these severe cases full recovery has been possible and only a few deaths have been reported.
Zika virus’s association with microcephaly in babies was discovered in Brazil because of their amazing research done with the most recent outbreak. Brazilian authorities found Zika virus RNA in amniotic fluid samples collected from two pregnant women with fetal microcephaly. An outbreak of Zika in French Polynesia 2015 associated with increased fetal abnormalities. Unfortunately, microcephaly is not the only risk resulting from the virus. Severe neurological damage to the baby has been found even with babies whose heads are of a normal size. Loss of hearing and blindness are also issues found, not to mention, long term neurological developmental issues not yet seen as the child develops. Some of these children have also been found to have a shortened life span.
Women are most at risk contracting this virus and research has shown that women in their first trimester are most vulnerable, if the virus is contracted after that time period the risk goes down tremendously. In those affected in the first trimester the risk in 1-13%. Research has a current estimate of 1.7m child bearing women will be infected in the Americas in the first wave, meaning tens of thousands will be affected. We need to take into account how this virus can be transmitted. Geographical range of the mosquito is number one, seasonal factors, travel by infected people, sexual or other spread. It is important to know that a man can sexually transmit Zika to a female partner. Early research showed that a man could carry the virus in his sperm for up to 8 weeks, but now it could be as long as 6 months. If you plan on having a child you should use protection for at least 6 months before trying to conceive.
Now that we have a general understanding of the Zika virus what mosquito carries it and how can we prevent the spread of this horrible disease?
There are two mosquitoes found to be vectors of Zika and they are Ades Aegypti and Ades Albopictus, both of these mosquitoes look similar to one another. Most entomologists will agree they are the most striking of the mosquitoes. Ades Albopictus known as the tiger mosquito can live in temperatures as low 62.6 degrees to 74 degrees Fahrenheit. The Ades Aegypti need higher temperatures to survive, they are more suited to a range from 73.2 to 82.9 degrees Fahrenheit. Unfortunately, both of these mosquitoes can survive harsh conditions, their larvae can survive starvation and neither species need large pools of stagnant water to lay their eggs in. These mosquitoes can lay up to 100 eggs on damp parchment paper, cracks in bark, used tires, pretty much anything that can hold a minimal amount of moisture. Right now the number one cause of spreading these mosquitoes throughout the world is due to the used tire trade, it is said that there is 1 tire to every human on earth…so I do not see that trade slowing anytime soon. This is not to say we are in a hopeless situation! Do not forget the Panama Canal, during its construction we battled and won the war with mosquitoes causing yellow fever.
We have methods that will help stop the spread of these mosquitoes; the method with the greatest success is Clean Up. Getting rid of the catch all’s that will hold enough moisture to sustain the larvae into the pupae has worked very well and does not create resistance. Education will always be a close second because when we are aware of a situation and have the proper tools to fix the problem, nothing can stop us. Larvaciding works wonders by using a bacterial agent called BTI this method does not allow new mosquitoes to emerge. Outdoor fogging has shown pretty good results if used with indoor/outdoor residuals. Water covers work very well from stopping the mosquitoes from having places to lay the eggs and works hand in hand with clean up.
Our ever evolving planet and climate will always throw us environmental curve balls. With knowledge and the ability to work together we will be able to combat all of what comes our way! Peak mosquito and Tick season is weeks away here in New Jersey…as we all know too well we go from 20 degrees to 75 in a matter of weekends. Do you have a game plan for mosquito and tick season??? Call us at Monarch Pest Control Corporation and mention my Zika blog I will give you $25 off any Lawn Guard Package you choose, for a limited time only!
***Above information came from Gresham College speech. CDC, EuroGeographics MOH Brazil (us/ms-las update 11-23-2015)