Zika Virus Updates


CDC chart describing the major symptoms of Zika Virus in adults. (CDC.gov)

It has been a while since I have posted about Zika Virus. As the US mosquito season is peaking currently, I felt it would be appropriate to do so. Here are some important updates, based on some news articles I noticed in the past week:

  • Currently in the USA, the overall Zika Virus incidence rate is much lower than it was last year. In New York for example, the current infection level is approximately 55% lower than last year at this time.
  • In Central and South America, many countries are seeing a decline in Zika infections, however there are no countries where Zika Virus is disappearing. Interestingly, Argentina and Peru are seeing Zika levels increasing lately.
  • It is likely that the broad declines in Zika infections within the Americas are due to an increase in the natural immunity to the virus throughout the population. Once someone has been infected with Zika once, they cannot be infected again and cannot pass the virus onto other mosquitos. These mechanisms help decrease the spread and infectivity of Zika Virus.
  • Due to the sexual transmission of Zika Virus, the US government has amended their guidelines to inform Americans who have been exposed to Zika. Currently, women who have Zika symptoms should wait approximately 8 weeks before attempting to get pregnant. Men, however, should wait approximately 6 months before engaging in sex. The differences in time are due to Zika surviving longer in the testes than initially expected. (For a review of the symptoms of Zika Virus in adults, please see the graphic at the top of this post!)
  • On the research front, scientists have created a mouse model to study Zika virus’ life cycle and transmission characteristics. Creating this research model is a great advancement as it will allow scientists to gain more knowledge on the virus and allow us to make advancements in the prevention of its spread and treatment.

While Zika is currently less talked about than it was last year, it is still prevalent and should not be forgotten. I’ll post more updates as the news behind Zika Virus develops.


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Zika Virus – An Overview

When you turn on your TV or open a news app on your phone, you are surrounded by talks about the Zika Virus. While the news focuses on Zika Virus as it is spreading through the Americas, little is being reported on its history in the world. Earlier this week, an article written by Jon Cohen was published in Science that briefly traces the history of Zika virus from when it was first discovered to the present day. Below, I will present an overview of some of the main historical facts presented in the article to set the stage for more posts about Zika in the weeks ahead…

  • The first reports of Zika Virus occurred in April of 1947 from a group of scientists studying yellow fever in the Zika Forest in Uganda. These scientists observed a rhesus monkey with an abnormal fever. At the time, they were unsure what the virus was. The virus was isolated and injected into mice to check for the possibility of transmission.
  • A few months later, the same scientists discovered the same virus infecting the Aedes africanus Again, this virus was checked for transmission and it matched the virus isolated from the rhesus monkey. The scientists named it Zika Virus, after the Zika Forest that it was discovered in.
  • One of the first scientists to examine Zika Virus’ mechanism of transmission was William Bearcroft. Bearcroft injected himself with isolated Zika Virus and waited until he had symptoms of the disease – headaches and a slight fever. Once he noticed symptoms, Bearcroft allowed female Aedes aegypti mosquitoes to bite his left arm. He took these mosquitoes to healthy mice, allowed them to bite the mice, and later observed the symptoms of Zika in the mice. This simple experiment confirmed that Zika Virus is transmitted by mosquitoes to humans and other organisms.
  • Since these initial discoveries, Zika has not been extensively studied, as other, more pressing and emergent diseases came to light
  • The latest outbreak, currently occurring, is the largest recorded Zika outbreak. Due to the greater number of infected individuals, scientists will be able to study the virus more accurately and in greater detail.

In today’s outbreak, many news articles are detailing the correlation of Zika Virus and increased rates of microcephaly (abnormally small heads) in newborns in countries such as Brazil. While this at first sounds terrifying, it is important to realize that there is no proven link between the two observations, and it is currently only a possibility. The CDC has published a study detailing how there may be an association between Zika Virus and Microcephaly, but cautioned that prior to the Zika Virus fear, newborn head sizes were not recorded as accurately in many regions of Brazil, meaning that cases of microcephaly prior to Zika’s appearance could have slipped past the statistics. Currently, only 270 cases of suspected microcephaly have been confirmed, from the initial, newly identified 4,180 cases. Of these 270 newborns, only six were found to have the Zika Virus inside of them. It is important for this message to get out to the general public so fear and panic does not set in. While we do not know much about Zika Virus yet, it is important for the scientific community, the news media, and the general public to hold out on passing judgement until claims are proven.

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