Tag Archives: mosquito

08.06.17
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Zika Virus Updates

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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.

 

For More information:

02.02.17
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Yellow Fever

Yesterday afternoon, officials at the Centers for Disease Control (CDC) issued an alert for travelers heading to parts of Brazil. According to the official alert, officials in Brazil’s Ministry of Health have stated that there is an ongoing Yellow Fever outbreak that started in December of 2016. Initially in the Minas Gerais state, cases are now being seen in Sao Paulo and other surrounding areas. It is estimated that over 400 individuals have been infected thus far, with 40 confirmed deaths in humans and possibly 400 deaths in certain species of native monkeys. In an effort to fight back against the spread of this disease, Brazilian authorities are launching a widespread vaccination campaign to help immunize those who are currently unprotected. The CDC recommends that those traveling to effected areas of Brazil get vaccinated against yellow fever, or receive a booster if their last vaccination was over 10 years ago. Currently, there is a shortage of yellow fever vaccine, so getting vaccinated may take longer than usual.

minas-gerais

Map of the Brazilian state of Minas Gerais, initial site of the current yellow fever outbreak. Brazilian officials are beginning to see yellow fever cases in neighboring Sao Paulo (v-brazil.com)

Here are some facts about Yellow Fever to help keep you informed:

  • The Yellow Fever Virus (YFV) is an RNA virus of the genus Flavivirus – the same family of viruses that includes Dengue and Zika Virus
  • Yellow Fever is commonly found in South America and Africa
  • As with many other diseases, yellow fever virus is a vector-borne disease that is spread through the bite of an infected mosquito, either the Aedes or Haemagogus The virus can be spread to other humans if a mosquito bites an infected human and transfer virus with it while taking a blood meal.
  • Most individuals who become infected with yellow fever will experience no symptoms or mild symptoms. For individuals who do experience symptoms, it usually takes between 3-6 days for them to appear after being infected. Common symptoms include:
    • Sudden fever
    • Chills
    • Severe headache
    • Body aches
    • Nausea / vomiting
    • General weakness and fatigue
  • In some cases (15%), the disease takes a severe course and includes symptoms such as high fever, jaundice, bleeding, shock, and possibly, death.
  • There is no treatment for yellow fever, so hospitalized patients will receive general supportive care until the disease works its way out of the body

How to minimize your risk of contracting yellow fever:

  • Get vaccinated!! Unlike other diseases in its family, the yellow fever virus vaccine is very effective at inducing immunity and does not require a booster in most cases. If you live in or are traveling to a region where yellow fever has been known to transmit, getting vaccinated is one of the best ways to remain safe
  • Use mosquito repellent – repellents containing DEET, picaridin and oil of lemon eucalyptus have been proven to work the best
  • Wear appropriate clothing – long sleeve tops and long pants are most effective at minimizing the amount of exposed skin that a mosquito could bite
  • Avoid going outside at dusk and dawn – mosquitoes are most active during these times, so avoiding them will help minimize your risk of being bit

 

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The Aedes mosquito, one of the species of mosquito that is involved in the transmission of yellow fever (bbc.com)

 

For more information, please visit:

CDC Yellow Fever Information

CDC February 1, 2017 Travel Alert

CDC Guidelines for Proper Mosquito Repellent Use

04.28.16
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Chikungunya

When thinking about what to write this week, I was torn with what to write about. One of my classmates suggested that I write about Chikungunya, as she knows it affects many Caribbean countries. Looking into Chikungunya, I also see that this disease ties in nicely with the diseases I have already blogged about because, similar to Zika, it is transmissible via mosquitos. Below, I will talk about some of the major facts about Chikungunya, and describe how it is affecting the world today…

  • Chikungunya is a viral disease that was first noticed in Tanzania in 1952. When the first cases came in, this disease got its name based on one of the major symptoms that it causes. In the Kimakonde language, Chikungunya is derived from a word that means “to become distorted,” referring to the appearance of many patients.
  • Chikungunya is transmitted by mosquitos, primarily the Aedes aeqypti and Aedes albopictus Interestingly, these two species are also famous for transmitting other mosquito-based diseases, such as Dengue and Zika. Once bitten by an infected mosquito, Chikungunya symptoms can set in within 4-8 days.
  • The major symptoms of Chikungunya include a sudden fever with severe joint pain. In most cases, the joint pain disappears after a few days to a week, but sometimes this pain can last several months or years. Other symptoms include nausea, fatigue, muscle aches, and headaches.
  • Chikungunya is difficult to diagnose based on symptoms alone, but simple blood tests can quickly and easily confirm the diagnosis.
  • Unfortunately, there are currently no antiviral drugs to fight Chikungunya. When patients are identified, treatment is usually targeted at relieving symptoms. Fever and joint pain are commonly treated using standard treatments. The virus is usually cleared by the body within a week or two, but sometimes it can remain for longer.
  • The best way to prevent yourself from contracting Chikungunya if you are traveling to a region with high Chikungunya levels is to take efforts to prevent mosquito bites. Wearing long-sleeve shirts, pants, and mosquito repellents are internationally accepted standards to prevent mosquito bites. In addition, using mosquito nets, or ensuring that mosquito screens are installed in any room you stay in are also effective ways to minimize your contact with mosquitos.
  • Currently, Chikungunya is afflicting over 60 countries worldwide.

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Where Chikungunya transmission is present, as of October 2015 (CDC.gov)

For more information:

http://www.who.int/mediacentre/factsheets/fs327/en/

http://www.cdc.gov/chikungunya/

 

04.12.16
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Zika Virus Update!

So, it’s been a while since I first wrote about Zika Virus… Today, almost every major news outlet carried the story that the Deputy Director of the CDC publicly stated that “Zika is scarier than we initially thought.” Today alone, I noticed this quote on the front pages of many news apps and papers. Given the fear that this headline easily instills in others, I figured this would be the perfect time to break down the facts of Zika, as it is currently understood.

  • Since my last Zika post, it has been shown that Zika Virus can be transmitted sexually, with 7 confirmed cases in the US mainland resulting from this.
  • Zika Virus is actively spreading throughout most of South America, all of Central America, and is beginning to spread through North America, including 30 states in the US.
  • Caribbean islands, especially Puerto Rico, are predicted to have a large increase in their number of Zika cases in the near future as we head into the summer months and there is increased interactions between mosquitos and humans
  • The CDC is warning women who are pregnant, or who are considering becoming pregnant in the near future, to avoid traveling to regions of the world where Zika Virus is actively transmitting.
  • Zika virus has been linked to an increase in the rates of microcephaly, particularly in Brazil, however not all pregnant women who contract Zika Virus will give birth to babies with deformities
  • It is possible that Zika Virus is associated with an increase rate of other birth defects, including vision problems, auditory deficits, and abnormal growth
  • As with many diseases, if you are infected with Zika Virus and the body fights off the infection, there is little to no risk that you will contract the virus again given your body’s immune response and memory
  • The White House, as recommended by the CDC, is diverting $589 million dollars in funding that was earmarked for Ebola prevention to promote research into the Zika Virus
Zika Map April 12 2016

Map showing the countries where Zika is actively transmitting, as of April 12, 2016 (CDC.gov)

There is still much to learn about Zika Virus and the research community is examining new ways to study, diagnose, and treat Zika Virus. As more developments arise, I will definitely post more updates to keep you informed! Thanks for reading my blog, and please let me know if you have any questions or comments about any of the diseases I have talked about so far. If you have suggestions for other diseases for me to talk about, please comment them below!

 

Read more:

http://www.usatoday.com/story/news/politics/2016/04/11/scarier-than-we-initially-thought-cdc-sounds-warning-zika-virus/82894878/

http://www.cdc.gov/zika/pregnancy/question-answers.html

 

 

03.14.16
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Malaria

While the news has continued to focus on new developments in the Zika Virus, another, more-widespread virus, is utilizing mosquitos as a mode of transmission. Malaria is caused by Plasmodium parasites, and is transmitted to humans by the Anopheles mosquito. The life cycle of Plasmodium parasites occurs in both mosquitos and humans.

Malaria Lifecycle

Plasmodium life cycle  (CDC.gov)

When the parasite is brought to humans by the mosquito, the parasite infects and begins causing symptoms. In mosquitos, the parasite lives without affecting the host in a negative way. As seen in the map below, malaria is most commonly noticed in central Africa, parts of Asia, and some countries in South America. Malaria is also seen in less frequent amounts throughout central and eastern Asia, central America, and parts of Mexico. Children, pregnant women, those who have compromised immune systems, and those who have never traveled to a region with Malaria are most at risk to contract the disease.

Malaria Distribution

Distribution of malaria transmission rates throughout the world (CDC.gov)

 

Malaria usually presents 7-30 days after being bitten by an infected mosquito. Many times, malaria is treatable if diagnosed quickly. The primary symptoms include fever, sweats, headaches, chills, and vomiting. As the disease progresses, generally in the next 48 hours after symptoms are first observed, symptoms can worsen, including seizures, kidney failure, hypoglycemia, blood coagulation, and severe fevers. If not treated quickly, malaria can become fatal.

Fortunately, there are treatments available for those who are diagnosed with malaria, and many are effective if started quickly after diagnosis. Many drugs focus on killing the parasite that causes malaria. While these treatments exist in the United States and other developed countries however, they are not as accessible in many of the regions that are hit the hardest by malaria.

 

For more Information:

http://www.who.int/mediacentre/factsheets/fs094/en/

http://www.cdc.gov/malaria/index.html

02.11.16
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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.

For more information, visit:

http://www.sciencemag.org/news/2016/02/zika-s-long-strange-trip-limelight?utm_campaign=email-news-latest&et_rid=17103660&et_cid=263974

http://www.cdc.gov/mmwr/volumes/65/wr/mm6503e2.htm

http://medicalxpress.com/news/2016-01-brazil-microcephaly-cases.html