Tag Archives: mosquito

Dengue Fever Virus: What Is it?

Warning for those who suddenly begin to feel fatigued, nauseous, and sport a severe headache! This is a warning sign that the mosquito bites you received on your trip through a tropical region a few months ago may have introduced a deadly virus into your body. At this point, you could be infected with Dengue fever virus.

A map detailing the prevalence of Dengue virus back in 2005. From Wikimedia.

 

According to an article published by Anne Gubler in Trends in Microbiology, Dengue fever virus originated from the tropical regions of the Earth during the 18th to 19th centuries. The virus is mainly spread through a species of mosquito, referred to as Aedes aegypti, which still populate the tropical and some subtropical regions today. However, as human population continues to increase in these areas, the risk for another epidemic outbreak increases. This is due to the ease at which a mosquito can travel from host to host, spreading the virus at a much higher speed. Recently, outbreaks of Dengue have intensified in all tropical regions resulting in an increase of reported infections and deaths. This makes me extremely cautious of visiting countries that are infested with mosquitos carrying Dengue and I’d like to spread some information about what it is.

 

General cross-section view of a Dengue virus. From Wikimedia.

The structure of a Dengue virus consists of a core, an envelope, and proteins attached to it. The core contains the genetic information of the Dengue virus. This genetic information codes for the production of a new virus as well as the creation of a new core, envelope, and envelope proteins. The viral envelope can fuse with the outside of a human cell, and also allows for the attachment of proteins. The envelope proteins are used to attach the virus to the outside layer of a human cell.

 

A study done by Karen Clyde sheds light on how the virus uses a replication cycle that involves entering a healthy human cell and hijacking numerous cell processes to complete replication. First the virus attaches to a human cell using proteins on the outside. Then the human cell brings the virus into its body, resulting in the release of the virus inside the cell. The next step involves the formation of a structure for reproducing the virus using materials found in the human cell. Finally, this produces a chain of viral proteins which are broken apart to form the final product of a core surrounded by an envelope with proteins.

 

In my opinion, travelling through a foreign country and having to be constantly aware of mosquitoes is annoying, but well worth the effort. Next time you travel through a country at risk of Dengue infection, make sure to coat yourself in bug repellent. As there are no known vaccines or treatments for Dengue, once infected, it will accompany you for the rest of your life. Therefore it is up to you to take appropriate precautionary measures to protect yourself.

The Zika Virus: Are we done with it yet?

Zika virus transmission. Imagine courtesy of World Health Organization (WHO).

In April 2015, an epidemic of the Zika virus disease took Brazil by storm , quickly spreading through South America and parts of North America. The disease was relatively unknown but it was associated with causing microcephaly, a brain defect where a baby’s head is significantly smaller than normal in fetuses of pregnant women with the Zika virus. As time passed with nearing proximity to the 2016 Summer Olympics in Rio de Janeiro, the possibility of contracting the disease caused so much concern that many athletes withdrew from competition.

But the Zika virus is not new.

It was first discovered in 1947 in monkeys of the Zika Forest in Uganda. Since then, there have been small outbreaks in the equatorial Africa and Asia. Unfortunately, due to the mild symptoms of the disease and it’s similarities to dengue, yellow fever and chikungunya, it was often overlooked and underreported until its recent outbreak.

The virus is mainly spread by mosquitoes of the Aedes genus common, namely A. aegypti and A. albopictus. Transmission to a fetus during pregnancy increases the risk of many birth defects such as microcephaly in the newborn child. If that doesn’t sound scary enough, it can also be spread from sexual activity and blood transfusions!

Microcephaly in newborn infants as a result of the Zika virus. Image courtesy of the Boston’s Children’s Hospital.

So what are the symptoms? Infections from the Zika virus will only display mild symptoms at most, including fever, rash, joint pain, pinkeye (conjunctivitis), muscle pain and headache. Symptoms typically subside after a week. Travellers and pregnant women who have recently visited affected areas should be tested for the disease.

The Zika virus is no longer an epidemic by the World Health Organization (WHO) as of November 2016 and it seems like something of the past. But why should we still be concerned about it?

Sadly, just because it is no longer an epidemic doesn’t mean that you shouldn’t be worried. Right now there is no cure for the Zika virus. Vaccines are being developed as we speak, but they probably won’t be available for another 10 years. For now all we can do is take precautions against mosquito bites and avoid travelling to places affected by Zika, especially if you are pregnant.

The problems Zika poses are far from solved. The Zika virus outbreak highlights the just one of the detrimental effects that poor sanitation has on our population. If we don’t solve the problem of managing mosquito populations and inventing new vaccines, we will have persisting human vulnerabilities to mosquito-spread diseases. We will always be at risk of infection to a disease we haven’t cured.

In the meantime, be mindful of your travel plans and check out this video on the Zika virus!

  • Florence Ng

Dengue Fever Virus: What Is it?

One day, while you are on a tour through India, you notice that mosquitoes have bitten you several times while you were unaware. You disregard it, thinking that these bites have never amounted to anything more than an annoying itch on a bump in the past. However, several months after returning home, you begin to feel fatigued, nauseous, as well as sporting a severe headache. At this point, you may have been infected with Dengue fever virus.

General cross-section view of a Dengue virus particle. From Wikimedia Commons.

According to an article published by Anne Gubler in Trends in Microbiology, Dengue fever virus originated from the tropical regions of the Earth during the 18th to 19th centuries. The virus is mainly spread through a species of mosquito referred to as Aedes aegypti, which still populate the tropical and some subtropical regions today. However, as human population continues to rise in these areas, the risk for another epidemic outbreak further increases. This is due to the ease at which a mosquito can travel from host to host, spreading the virus at a much higher speed.

General cross-section view of a Dengue virus particle. From Wikimedia Commons.

The structure of a Dengue viral particle consists of a core, an envelope, and proteins attached to it. The core contains the genetic information of the Dengue virus. This genetic information codes for the eventual production of a new viral genetic strand, as well as the creation of a new core, envelope, and envelope proteins. The viral envelope can fuse with a host cell membrane, and also allows for the attachment of proteins. The envelope proteins are used to attach the virus to the receptors located on the outside membrane of a host cell.

A study done by Karen Clyde sheds light on how the virus uses a replication cycle that involves entering a healthy host cell and hijacking numerous cell mechanisms to complete replication. Firstly, the virus binds to a host cell using its envelope proteins. Secondly, the host cell internalizes the virus, resulting in the release of the viral package inside the cell. The next step involves the generation of a viral replication enzyme using host cell structures before the virus genome can be replicated. This eventually results in the production of a chain of viral proteins, which are cleaved apart to form the final product of a core surrounded by an envelope with proteins.

Next time you travel through a country at risk of Dengue infection, make sure to coat yourself in bug repellant. As there are no known vaccines or treatments for Dengue, once infected, it will accompany you for the rest of your life. Therefore it is up to you to take appropriate precautionary measures to protect yourself.

-Angus Lee