Friday, September 16, 2016

CCHF: The Western European Tour

In 1944, a tick-borne virus characterized in Crimea was name "Crimean hemorrhagic fever virus", yet 25 years later, the vector was identified in the Congo. Hence, Crimean Congo Hemorrhagic Fever, or CCHF for short, was born (in the "I've given this naturally existing thing a name so it shall be seen as new" sense). As all vector-borne diseases are limited by the regional distribution of their vectors, it is no surprise that news outlets are currently describing CCHF as a "new" viral disease. Spread primarily by the Hyalomma species of tick, CCHF has been historically limited in spread, with cases primarily showing up in certain regions of Africa, the Middle East, Eastern Europe, and some parts of China.

Map borrowed from the CDC (2014 version).
Let's look at some older maps that contrasts the distribution of the Hyalomma species and historical cases of CCHF:

Map from the WHO in 2008

Image from

There are a number of factors that have contributed to the spread of CCHF virus. CCHF virus is a zoonotic virus, meaning animals, such as livestock and domesticated animals, may also be infected. Many species of birds appear to be resistant to CCHF virus, with the exception of ostriches. Outbreaks have been linked to ostrich abattoirs (or slaughterhouses) in South Africa, but the animals do not present with disease symptoms or consequences. Primarily cattle, goats, sheep, camels, and hares or rabbits are susceptible, and act as the amplifying host. Humans can become infected as a result of contact with an infected animal tissue or blood, so it is easy to see why herders and abattoir workers are at high risk for exposure. Human-to-human transmission is possible through contact with infected bodily fluids, which puts health workers at risk as well. Cases have been traced back to exposure through contaminated medical equipment, although that is fairly rare.
Viral life cycle image via the CDC
So why are we seeing CCHF virus labeled as "new"? "New" is the media's historically ignorant term for "emergent", meaning these infectious diseases have been around for a while (some for centuries, even), but environmental and civil factors are influencing spread to new regions. Even the slightest change in seasonal climate or average annual temperature can create a hospitable environment in places that were inhospitable to these disease vectors. We also have a very developed view of the world, where it is hard to see that human actions, such as spillover into forests regions for industrial purposes (extracting natural resources or large-scale plantations for the production of resources), and development purposes (houses, houses, everywhere), can influence the introduction of these diseases to new populations. Not only are the vectors moving into our developed areas, but we are constantly invading and inhabiting natural habitats and contributing to the zoonotic nature of these viruses (and other infectious diseases). After all, we are animals, too.

Forbes, with their obnoxious refusal to let you view articles on their website while using an adblocker plugin, says that you should be worried about CCHF. The first local transmission of CCHF virus was reported in Spain this year, and the patient died. A nurse was also exposed as a result of this case, which lead to close monitoring of many people from the medical team and local community. The presence of CCHF virus in Spain has been known since 2011, when the West African strain of CCHF virus was isolated from ticks in Caceres province. Up until that point, the Balkans were the western-most region known with reported cases of CCHF.

Onset of CCHF is quick, with sudden onset of high fever, severe headache, back and joint pain, stomach pain and vomiting. Patients may appear flushed with red eyes, face and throat, with a patchy red palate. Jaundice and the onset of neurological complications can arise.The hemorrhagic nature of the disease begins with severe bruising and frequent, severe nose bleeds, or uncontrollable bleeding at the site of injection. Outbreaks generally have a case fatality rate of 40 - 50%. Treatment is limited to supportive care, and there are currently no vaccines available to humans or for use in livestock populations.

Image from

Image from Wikipedia
There are many other hemorrhagic fevers, including Ebola virus (EBOV), Marburg virus (MBGV), Lassa virus (LASV), Rift Valley fever virus (RVFV), dengue virus (DENV), and yellow fever virus (YFV). Differential diagnosis, how we determine which virus is causing the hemorrhagic disease, is very difficult, as many of the symptoms overlap and rapid testing is not always available. In all of these viral hemorrhagic diseases, infection can impact liver cells and liver function. Impairment of liver function can decrease synthesis of protein that initiate clotting. This most likely occurs due to the body's response to severe disease and shock, as more liquid/unclotted blood can disseminate faster to all organs. Infection of liver cells can also cause an increase in clotting proteins, causing small clots to form, blocking blood flow. Hemorrhagic fevers also effect the permeability of blood vessels, causing the severe bruising and bleeding in tissues and orifices, like the nose, gums, or vomiting blood as a result of severe internal bleeding.

If you are following the advice from Forbes, and deciding to worry about CCHF, take action. Check yourself for ticks after spending time outdoors in wooded areas, places with tall grass, or wild animal exposure. Wear long sleeves and pants while spending time outdoors to limit your skin exposure to ticks (you can even treat your clothing with repellent; learn how here). Lastly, if you find it a tick on yourself, be sure to remove it carefully without pulling the head off or smashing the blood-filled body. If you are worried about disease exposure from said tick, do your doctor a favor and save the tick! It can be sent to a lab and tested, but act quickly as these viruses can be difficult to isolate from old material.

Wednesday, August 10, 2016

Beasts Aplenty

The world is on fire about arthropod-borne viruses, or "arboviruses". The simple mosquito bite can transmit a battery of diseases, including the currently popular West Nile virus, dengue virus, and zika virus. While these viruses are not new, the emergent nature has taken our media by storm, and is illuminating the universe of zoonotic diseases.

There's one virus, though, that for me, was the original. This virus has infected history and popular culture alike, but still hasn't achieved the level of fear that we see with some of these other, more emergent viruses. The fact that more people aren't absolutely terrified of this virus is beyond me, considering that it is the most deadly virus in the world, whereas dengue and zika have relatively low mortality rates.

Image from 7 Bloodcurdling Werewolf Tales That Will Keep You Up at Night
The rabies virus is a unique, non-segmented, negative stranded RNA virus of the Rhabdoviridae family. Unlike most diseases that hijack the circulatory system for dispersal through the body, rabies attacks the nearest nerve. The virus actually replicates in the nerve cell, slowly moving up to the brain.

The rabies virus is quite literally shaped like a bullet. The lipid envelope is lined with glycoproteins that help with viral attachment.
The slow progression is part of the issue, because most people don't know they've been exposed to the virus until much later, when the symptoms start to set in. By the time symptoms occur, the virus has replicated and multiplied significantly, so a large amount of virus hits the brain.

The first symptoms are nonspecific and mild, with fever, weakness, headaches, and malaise. Some patients report a tingling and itching sensation at the site of the bite. After the nonspecific symptoms, confusion, anxiety, and agitation set in. Cerebral dysfunction leads to fits, and the body starts to lose the ability to sense temperature, pain, and pressure. These fits lead to erratic behavior.

It is common for patients to experience a phobia of water, too. As the virus is most commonly transmitted by bite, the fear of water is an evolutionary advantage for the virus. Without water, the virus is concentrated in saliva, without being diluted by water, making it more likely to be transmitted.

It is also possible for patients to experience "dumb rabies", with lethargic and comatose-like symptoms prior to death.

Once these symptoms start, recovery and survival is extremely rare. Disease progression usually lasts between 1 and 3 weeks, from start to finish. There have been only a small number of people who have survived a rabies infection, some from experimental treatments, and others for unknown reasons. Post-exposure prophylaxis of human anti-rabies antibodies needs to be administered before the onset of these symptoms, otherwise death is guaranteed.

Given its intense lethality, rabies has inspired a significant amount of medical development. Louis Pasteur developed the first rabies vaccine in 1885. Pasteur achieved successful development of the vaccine by serial attenuating, or weakening the virus in rabbits.

Rabies kills approximately 60,000 people a year, worldwide. We don't typically worry about it here in North America, due to pet vaccination and local animal control, so most of the deaths occur in poor, rural, and developing regions of the world. In the last two weeks, though, Sheffield, MA has been experiencing the worst rabies outbreak in decades. Residents of Sheffield have reported rabid foxes, skunks, and even a RABID WOODCHUCK.

Rabies has played an integral part in the development of some of the most horrific monsters. The concept of man morphing into a wild beast evolved from human exposures to animal diseases. The best examples of this are the werewolf and Dracula (or, vampires in general).

It all starts with a bite.

Tuesday, May 17, 2016

Brought to you by the letters HBV

May is Hepatitis Awareness Month (according to the CDC), so I'm going to focus on something I get inquiries about all the time.

Hepatitis is a viral disease that can cause liver damage that can progress to liver inflammation, scarring (fibrosis), cirrhosis, or liver cancer. Disease progression depends on the virus, and other existing health issues (excessive use of alcohol and other substance abuse, autoimmune disease, etc.).

There are 5 viral types of hepatitis, aptly named A, B, C, D, and E (or HAV for Hepatitis A Virus, HBV for Hepatitis B Virus, and so on). We don't usually hear about hepatitis A and/or E here in the US, because they are transmitted by ingesting contaminated food or water (you're more likely to get listeriosis here!), which is mostly associated with developing countries and poor sanitation. If your an avid traveler, you've probably already received a HAV vaccine.

Hep B and C, though, are common in the US, and worldwide, and this is where the the inquiries come in. Hep B, C, and D are spread by contact with contaminated bodily fluids, such as blood and semen. The most common methods of transmission are through unprotected sex, and through sharing or using contaminated needles (drug use, tattoos, piercings, birth, and medical procedures). There are vaccines available for Hep B and D, but not C. Actually, the HBV vaccines also protect against HDV! Since most people do not know they are infected with a hepatitis virus, and HBV, HCV, and HDV are prevalent worldwide, the HBV vaccine is recommended for all newborns in the US.

Hep B and C kill more than 1 million people every year, and its not an easy death. Liver disease is painful, and the treatments few treatments for hepatitis can be incredibly expensive. So, to answer everyone's question all at once: Yes, I do believe the recommended vaccine schedule is necessary and important for your child, and all children for that matter. 

Before I go on, let me just say that, as someone doesn't have kids of my own, I can't imagine how scary it must be at the beginning. The dichotomy of wanting to protect your kids from everything while not having them undergo a ton of procedures and get a bunch of shots because they are fragile little beings must be scary. It's ok to try to figure out what is right for you and your child, because some things are unnecessary (baby yoga? I don't know)! But, I believe vaccines are not one of those unnecessary things.
The following are most common things I hear about the HBV vaccines from concerned parents. Just a note: my language in this section is referencing people who do have access to regular medical care, and may or may not be taking advantage of it. This is something that all parents should have access to for their children, but sometimes it just isn't possible (for a number of reasons). Most often, people who are questioning the use of the HBV vaccine (and others) do have access to quality medical care, yet choose not to follow the guidelines. Descriptive demographics of the people who are chosing not to vaccinate their children include white, upper middle class or upper class, and college graduates.

So, with that being said, here are the most common things I hear about the HBV vaccine:

1. "Why would I give my baby a shot (3 to 4, actually!) for something you can only get from having sex?"
There are so many assumptions being made here. First of all, you should be glad that you have access to, and are benefiting from the privilege of having access to vaccines for your child and yourself. Most kids don't get vaccines, because they aren't mandated or they are too expensive or not available to them based on where they live. The fact that you and your child get to benefit from that is not something at which to scoff! Many children don't even live past the first few years of life because they don't have access to quality medical care and treatments.

Secondly, over 2 billion people have been exposed to hep B, and as I stated above, most people don't know that they are infected. That means there are many opportunities for your child to unknowingly be exposed. There are even opportunities for family members who don't know that they are infected to expose your kid during infancy. This vaccine will protect your child through their exploratory stages, when you might not always be around. I can't even tell you how many kids at my middle school thought blood pacts weren't serious (I think we can mostly blame that on 90s movies, right?), or in high school when everyone experimented with making their own tattoo guns. Or even had unprotected sex because they were too embarrassed to buy condoms or felt too invincible because "well, I'm not going to get AIDS from you, right?" Let's face it, pretty much every kid, teenager and young adult makes odd choices when they are figuring everything out, and that exploration really shapes who they become as adults. So, if there is a vaccine available to them that may offer some protection throughout their lives, why would you deny that?

2. "It just seems like a lot for a newborn to handle." or, alternatively,  "That's a lot of chemicals to put into a newborn."
The hep B vaccine has actually gone through a few iterations before arriving at it's currently available form. In 1986, manufacturing switched to using recombinant DNA, which is significantly more safe (see: 100% safer, because it is physically impossible to get hepatitis from the vaccine) than the original product. The vaccine has been clinically tested (on many animals and humans) and approved for use in children. The recommendations set for these vaccines are based on a) the earliest safe and effective usage of the vaccine by the immune system (i.e. - will my immune system even respond to it?), how long the immune system response will last (will I need a booster shot in the future, or will this one time vaccine protect me for life?), and the need (will I potentially be exposed to the pathogen at this stage in my life?). There are many vaccines that kids in the US don't get, because they won't need them (see above where I explain that the hep A vaccine is mostly given to travelers headed to regions with poor sanitation). But, as stated above in #1, there are a lot of opportunities for people to be exposed to HBV and HDV.

3. "I'll just give it to them later in life."
Sure, do that, but they will hate you for it. I remember having to get my hep B vaccines. It hurt really badly! And I remember it hurting because I wasn't a newborn. Also, I don't say this as a scare tactic, but every day without the vaccine (or other ones, for that matter), are days that your child's immune system isn't primed and ready to go. So, for that reason, its really silly to wait, especially since most people don't need boosters.

4. "Why does anyone care what I do to my child?"
Every child without the vaccine is at risk of being exposed to the virus. If your child is infected at any point in their life, they have the ability to transmit (or spread) the virus to others, especially if they do not know that they are infected and do not take precautionary measures (using condoms, not sharing needles, etc.). Some people with compromised immune systems cannot get certain vaccines, and are therefore at a higher risk of getting infected, and developing chronic or severe disease. If you do not vaccinate your child, your child may be responsible for unknowingly spread the HBV or HDV to someone with a compromised immune system.

5. "Most people only have an acute infection that goes away on its own."
No, most ADULTS experience acute disease. Only 2-6% of adults develop severe or chronic hepatitis, whereas 90% of infected infants become chronically infected. The risk of pre-mature death due to liver disease and chronic complications from hepatitis (mostly liver failure and liver cancer) is increased by up to 25% if a child is infected in their first 5 years of life. Three shots can completely eliminate this risk for your child. The hep B vaccine can also eliminate the risk of hepatitis-linked treatments, like invasive surgeries, transplants, or cancer treatments, which increase the risk of premature death even more, and are just not easy for a child to endure.

If you are still questioning whether to vaccinate your child for hepatitis B, I recommend you talk to your pediatrician about the statewide mandated guidelines and federal recommendations. As I stated earlier, I'm sure having a child is scary. There is a lot of information out there, and it is hard to know what to believe. But, vaccinations are not something that should be questioned. It has been proven time and time again that they are safe to your child, and safe for the community, and have effectively eradicated some diseases. It is okay to be cautious, but it is also okay to trust science.

Happy Hepatitis Awareness Month!

Sunday, March 20, 2016

Elizabethkingia: The Bacteria That Kicks You While You're Down

What's your biggest fear? Sharks? Heights? Cancer?

Compared to exciting threats like sharks, or falling to your death when your bungee cord snaps on your honeymoon bungee jumping excursion, infectious diseases fall pretty low on the list for most Americans. We've eradicated a number of diseases through rapid urbanization/industrialization (did you know that malaria was endemic in North America in the early decades of the union?), large-scale waste management (bye, cholera!), and widespread use of vaccinations (see: smallpox, polio, etc.).

An agar plate of bacteria and mold, from NationWell

There's a number of things to which Americans are not immune, and a large category of them is bacterial infections. I say "category", because the variety of pathogenic bacteria in the U.S. can be broken into a number of subdivisions, such as: sexually transmitted infections (those which are caused by bacteria), antibiotic/antimicrobial resistant bacteria, those spread by environmental exposure (like Borrelia spp. that causes Lyme Disease, which is transmitted by ticks), and nosocomial bacterial infections (also known as hospital-acquired infections), just to name a few.

The most well-known subdivision I mentioned above is antibiotic/antimicrobial resistant bacteria. In fact, over two million people in the U.S. are infected with antibiotic/antimicrobial resistant bacteria each year. You can dig deeper into the world of antibiotic/antimicrobial resistant bacteria on the CDC website, which rates bacterial species based on the severity of the threat they pose

Nosocomial infections, specifically, caused approximately 1.7 million infections and resulted in  99,000 deaths in 2002 (according to an estimate report from the National Nosocomial Infections Surveillance System). A similar surveillance survey by the CDC in 2011 reported over 720,000 nosocomial infections in acute care hospital facilities.

Get more information on the CDC's Hospital-Acquired Infection Data and Surveillance Report here.

I bring this up because in the span of 4 months, a bacterial infection called Elizabethkingia anophelis has killed 18 people in Wisconsin and 1 person in Michigan.

Elizabethkingia is the phylogenetic genus of 4 related species of gram negative bacteria:
  • E. anophelis, which causes respiratory infections in humans, and was originally isolated from the midgut of Anopheles mosquitoes
  • E. endophytica, which is a plant pathogen that mostly infects Zea Mays, or sweet corn
  • E. meningoseptica, which causes severe meningitis and sepsis in newborns and infants (premature newborns are particularly susceptible)
  • E. miricola, which was miraculously (pun!) isolated from condensation water on the Russian Space Station, Mir.
The genus is named after Elizabeth Osborne King, a clinical microbiologist (and a #WomanInSTEM!) who worked for the CDC in the 1940s through the 1960s, and studied meningitis in newborns. E. anophelis is common in environmental reservoirs, such as water and soil, but rarely causes infections in humans. The CDC logs only a handful of reported cases in the US each year.  

Yet, in Wisconsin, approximately 54 people have been infected since November of 2015. The outbreak is mostly affecting people who are 65 years or older, most of which had underlying health conditions. E. anophelis infects the bloodstream and occasionally the respiratory tract, causing nonspecific symptoms, including fever, chills, shortness of breath, and cellulitis. Death is usually a result of sepsis.

The current outbreak has been tracked across 12 counties, but has not specifically been labeled as a hospital-acquired infection. Infections of the current outbreak have been centered in the southeastern quarter of the state, including the Milwaukee area and surrounding suburban counties. One case in Hong Kong illustrated that the infection can be spread from mother to child. E. anophelis is an antibiotic resistant species, which is why the magnitude of the current outbreak is causing such alarm for medical professionals. Transmission from person-to-person is highly unlikely without blood-to-blood contact, meaning there must be another common source within the community. The transmission route for the most recent outbreaks that occurred prior to the current one in Wisconsin, one in Central Africa and the other in Singapore, was not determined.

So, how does this factor into our biggest fears? The infectious disease world is constantly discussing the concept of "emerging diseases", meaning rare infections that are suddenly migrating to naive populations (meaning, the population of that geographical region has never been exposed to the pathogen before) or are infecting new populations. Antibiotic resistant bacteria, like Elizabethkingia anophelis, are sometimes included in the description of emerging diseases because the acquired or developed resistance poses new problems for treatment and infection control.

Say you go to the hospital because your appendix has ruptured. This is a routine surgery that shouldn't take much time or effort. But being in the hospital puts you at risk for infection, especially when you are in the process of recovering from a routine, but intensive, procedure. If the infection is rare, it will take your doctor a longer time to identify the culprit. If the infection is resistant to common treatments, you will have to endure more extensive treatment programs. If you are recovering from a surgical procedure, or have other open and exposed wounds, you're immune system may be otherwise preoccupied. So, a short hospital stay that should have been routine, might end up being more extensive, or putting you at a higher risk for death.

If you would like to follow the outbreak in Wisconsin, the Department of Health Services website is updated every Wednesday regarding developments in the investigation.

Wednesday, February 17, 2016

On to the Next One

Jay Z, image from Newsweek

Isn't it phenomenal that there's always a newer, more pressing issue on the horizon? In the words of Jay Z:

"Ya'll should be afraid of what I'm gonna do next"

Now that the WHO has declared the ebola outbreak completely over (with a new case reported the very next day, whoops!)...

This is the first thing I thought of when I saw the declaration of the end of the ebola outbreak.

The new focus is on the Zika virus (ZIKV) outbreak in South and Central America. I've been waiting to write this post for weeks because the news coverage is so heavy, and I didn't feel like being redundant. Everyone has heard about this "new" virus, the "new" link to microcephaly, and most recently, the anti-GMO tie to Monsanto. But, what do we really know about ZIKV? Let's break it down:

ZIKV is not a new virus.
ZIKV is a single-stranded RNA virus of the Flaviviridae family. It is related to dengue virus (DENV), West Nile virus (WNV), yellow fever virus (YFV), and Japanese encephalitis (JE) virus.

ZIKV structure, thanks to St. George's University in Grenada
While newly introduced to South and Central America, ZIKV has been endemic in specific regions of Africa and Asia for quite some time. ZIKV was first discovered in Uganda in 1947, yet phylogenetic analysis of the viral genome estimate that ZIKV originated sometime between 1892 and 1947 (most likely in the 1920s). Early reports stem back to the 1950s, but with evolution of arthropod-borne viruses (arboviruses), the general and non-specific symptoms reported may have been caused by a similar virus (more on that later). Both urban and sylvatic, or rural/forest-based, transmission has been reported, and ZIKV is also seen in monkeys.

Yet, the recent and substantial outbreak in South and Central America (most notably in Brazil, which reported more than 14,000 cases in a matter of months) is new and a big deal. Prior to outbreak in 2015, ZIKV was wreaking havoc on islands like French Polynesia (2013-2014) and Easter Island (2014-2015). In fact, the outbreak in French Polynesia illustrated the link between ZIKV infection and chronic neurological conditions, specifically Guillain-Barré Syndrome

Pregnant women are always seen as an "at risk" or "high risk" group.
The human body goes through a plethora of changes and adaptations when pregnant, mostly because survival of the mother is imperative for survival of the fetus. Development of the fetus is directly dependent on the numerous resources that the mother's developed body provides. The most relevant to this blog is "immunological priming", that continues after birth through contact with the mother's microbiome during the birthing process and during breast feeding.  
Given the sensitivity of this relationship, pregnant individuals are always seen as a high risk group, as some pathogens can travel across the placenta, exposing the fetus during development and before birth. Trans-placental transmission/exposure to ZIKV is currently being investigated by a number of different institutions. With the increase in microcephaly cases during the ongoing ZIKV outbreak in South and Central America, it is understandable why a potential link would cause alarm. 

One important thing to note is that Brazil is one of the few places that already had baseline incidence and prevalence data for microcephaly, making the increase in cases easier to identify. That type of data hasn't been readily available during previous outbreaks in other regions, which makes it difficult to determine whether or not ZIKV is the immediate cause. 

A mosquito bite does not guarantee disease.
Unlike it's relative, dengue virus, it is estimated that only 20% of people infected with ZIKV will become ill and experience symptoms. That means 80% of people infected are asymptomatic (meaning, they do not have any symptoms and often do not know they are infected). Symptom of ZIKV are, much like the symptoms of other arboviruses, general and non-specific. This means you experience fever, headache, rash, and joint or muscle pain. ZIKV also commonly causes conjunctivitis, or redness and swelling of the eye and skin around the eye. 
Arboviruses have been threatening to spread to North America with increasing persistence for years.
Graphic from the Institute of Medicine's presentation on Zika by Dr. Victor Dzau (2/15/2016)
North America is an anomaly in the infectious disease world. Since clearing most of the natural forests to favor rapid urbanization and industrial usage of land and resources, most hosts and vectors for many infectious diseases just won't survive in these areas. Part of that is because a majority of infectious diseases are perpetuated by tropical climates that are hospitable to the hosts and vectors (think jungles and warm/wet environments). But, some of the hosts and vectors are durable, and have taken advantage of changes in climate and global travel. 

Many of the mosquito species that are required to spread these viruses have already established residency in California and Florida. So, as these viruses come closer to our geographical borders, and travel to/from endemic regions becomes more frequent, we may see some locally-acquired cases. But, the spread of a virus into a new region is a complicated process and so many factors have to overlap.

Sexual Transmission can occur, but is not common.
There have been isolated cases of sexual transmission, but the uptick in news coverage is only a result of the ZIKV madness people have seen to caught, and is most likely the mass media's way of "helping" figure out whether microcephaly is linked to ZIKV infection. Despite what you've heard, having sex with someone that has ZIKV on the head of their penis will not cause microcephaly in all of your future children. Thanks, internet.
It is common sense, from an evolutionary standpoint, if you think about it. If you are in a region where mosquitoes are plentiful and looking for a bloodmeal, you are more likely to be exposed to ZIKV by a mosquito. Yet, these viruses "survive" when they are passed from one person to the next. Without transmission, our immune systems would clear the infection or we would die, and that would be the end of the story. Your mucosal membranes are a perfect environment for transport from one human to the next, especially when small tears may occur, giving access to blood. 

Just because there is a statistical possibility for sexual transmission to occur doesn't mean it can be considered a main method of transmission. There have only been 3 confirmed cases to date of male to female transmission through unprotected sexual contact. 

When babies are at risk, money is dedicated to the cause.
In hearing that there may be a link between ZIKV infection and an increased risk for microcephaly, President Obama dedicated $1.8 billion to ZIKV research. This funding will go to the development of faster, cheaper, and more specific and sensitive diagnostic tests, vaccine development, immune profiling and characterization of ZIKV disease, and studies to definitively determine whether microcephaly in newborns can result from ZIKV infection in pregnant women.
If you are traveling to an endemic or high-risk area, you can protect yourself.
Arboviruses are some of the least feared diseases, from what I can tell based on my friends' reactions when I tell them to pack DEET and other mosquito repellents when traveling. Basically, if they are not at risk of getting malaria, they aren't worried. 
If you are worried and have travel scheduled, there is a page dedicated just to the prevention of ZIKV exposure and transmission on the CDC website.
Cartoon by Rob Rogers and (c) the Pittsburgh Post-Gazette
Now, let's all hold our breaths and see what happens during the 2016 Summer Olympics, which are being hosted in Brazil.