Zika Virus In The US

29 07 2016

We are all familiar with the word “Zika” because of the infections in Brazil.

The Florida Health Department and state officials have announced that they have identified four cases of Zika virus infection that were most likely transmitted locally. These cases are in Wynwood, an area just north of Miami

This is probably the first time that mosquito-borne transmission of Zika virus has happened in the continental US.mosquito

The CDC and Florida are saying “likely” and “probably” because, although they cannot yet prove these individuals were bitten by infected mosquitoes, there seems to be no other method of transmission in these cases, and the mosquito that carries the virus does live in the area.

However, this does not mean that the Zika virus will become widespread in the US.

The Zika virus is transmitted a few ways. The most common way for people to get the Zika virus is to be bitten by an infected Aedes species mosquito (Ae. aegypti and Ae. Albopictus).

This mosquito doesn’t like the climate in all parts of the US. Much of the northern area will not be at risk from this mode of transmission.

Also, this mosquito never travels more than 150 meters its entire life. That’s less than 1/10th of a mile. It usually travels far less than that distance.

The West Nile virus, on the other hand, was able to pretty much cover the US because the virus can be transmitted from an infected mosquito to a bird, which then flies off quite a distance before landing and getting bitten by a different mosquito, which then becomes infected. That mosquito, in turn, bites another bird. This cycle hopscotches its way across the US, spreading disease from bird to mosquito to bird to mosquito.

The mosquitoes also infect humans and other mammals with West Nile virus.

The mosquitoes that carry the Zika virus don’t work that way. They prefer to only bite humans.

Another reason the Zika virus will probably not explode across the US is because where the mosquito lives, people use screens across their windows and doorways, and they use air conditioning. It’s more difficult for the mosquito to get into the houses.

There are other ways for the Zika virus to be transmitted.

An infected pregnant woman can pass it to her fetus during pregnancy or around the time of birth.

An infected individual can pass the virus through sex with their partner. An infected person may or may not be symptomatic—they can still transmit the virus. It appears that four out of five infections are asymptomatic. One cannot assume that a person is virus-free just because they don’t seem to be sick.

An infected person may donate blood and the virus can then be passed through blood transfusions.

This virus is under a lot of scrutiny. New methods of transmission may be identified, but these are the primary methods at this time.

Now we have an idea of how it’s transmitted. What can we do about it?

Where pockets of infection have occurred, the state and local authorities have started aggressive mosquito control, including spraying and going door to door to alert residents to standing water. Mosquitoes love to lay eggs in standing water—making sure there is none helps to control the mosquito population.

We all need to prevent mosquito bites by using insect repellent containing DEET, wearing long sleeves and pants, and staying indoors unless covered and protected. This is particularly true for pregnant women, and for those living in areas where these mosquitoes are common.

For up-to-date info on Zika virus, visit http://www.cdc.gov/zika/





Zika Virus And Your Baby

26 01 2016

In 1947, a caged rhesus monkey in the Zika Forest of Uganda became feverish with what is now called the Zika virus.

Scientists researching yellow fever had stumbled upon something new.

Nearly 70 years later, this virus is making headlines. We first heard of the Zika virus when the media began reporting stories about infected newborns in Brazil.

microcephaly-comparison-500px

Women were giving birth to thousands of babies with microcephaly, a condition where the newborn’s head is unusually small compared to the rest of the body. When microcephaly occurs, the brain is usually underdeveloped, which can cause severe developmental delays and, possibly, death.

In 2014, there were 150 babies in Brazil born with microcephaly. In 2015, there were 4000+ babies born with microcephaly.

Just as mosquitoes carry malaria, yellow fever, and other diseases, so too do they carry the Zika virus. Mosquitoes are vectors, which means they’re living organisms or critters that can carry disease from animals to humans or humans to humans. They accomplish this by sucking infected blood from an animal or human, and then injecting it into the next human on whom they decide to feed.

The typical symptoms of an infection with the Zika virus are, overall, fairly mild. They can include a rash, reddening of the eyes, fever, muscle or joint pain, and headache. These symptoms stick around for about a week, give or take a few days.

The disease does not normally require hospitalization, and death from this infection is rare.

At this time, there’s no way to prevent or even treat an infection with the Zika virus. Perhaps the only thing one could do would be to prevent mosquito bites, but getting through a year without at least a few bites is nearly impossible.

In areas where the Zika virus is common, some pregnant women are becoming infected and then passing that infection to the fetus during pregnancy, or possibly around the time of birth, according to the CDC.

The outbreak is so alarming that the CDC is advising pregnant women to postpone travel to many Latin American and Caribbean countries where reports of significant numbers of Zika infections are coming in.

This virus is a traveler. The World Health Organization expects the Zika virus to spread to every country in the Americas, except for Chile and Canada.

Some researchers are saying that the soonest a vaccine could be developed would be three years, possibly five. Prevention, for the time being, is in the hands of the individual. Mosquito nets and repellents are useful, as is ensuring there is no still water in the area. Community spraying could be beneficial.

It’s important to note that so far there has been no actual link found between the Zika virus and microcephaly. But clues are definitely pointing in that direction.

For more information, visit www.cdc.gov/zika.

 

 

By Trish Parnell
Image courtesy of CDC





Why We Think Flu Vax Gives Us Flu (But We’re Wrong)

17 12 2015

My Uncle Wayne will swear that, in 2008, he was vaccinated against flu and within a week was laid up in bed with—yes—a case of flu.

A lot of us believe that getting the flu vaccine will infect us with flu, and here’s why that idea is so common (and so wrong):

Reason 1
The flu vaccine takes about two weeks to become effective in our bodies. If we’re exposed to a flu virus anytime just before or after our vaccination, our bodies are on their own.

Getting vaccinated and then getting the flu . . . it’s really just a matter of timing. Coincidence. The two events happen around the same time – getting vaccinated against flu and getting infected with flu – but one doesn’t cause the other.

Reason 2
Around this time of year, flu is what we hear about. The public health people are out in full force to get us vaccinated against the prevailing flu viruses. It’s called cold and flu season, but flu is the star.

But, there are cold germs and other viruses floating around that cause symptoms similar to flu symptoms. Our default thinking is that we have flu, but the reality may be that we have a bad cold, which also stinks, but is not influenza. So, it’s a misdiagnosis.

Reason 3
There are many flu viruses floating around the world. Each year, the World Health Organization and others try to determine which viruses will be dominant during that particular flu season. Sometimes they’re wrong, and the available flu vaccines, which were made to fight those specific flu viruses, don’t do a good job of protecting us from what’s really out there.

Reason 4
No vaccine protects 100 percent of the people 100 percent of the time. It’s possible to get vaccinated against the flu strains currently in your area and still end up with flu because, for whatever reason, the vaccine simply did not protect you.

Reason 5
You cannot get flu from the flu vaccine because it’s made to prevent that very thing from happening.

The flu vaccines that are delivered through a needle are made from totally dead flu viruses, or tiny specks of deconstructed flu viruses.

There is not a spark of infectivity left in them.

The flu vaccine that is sprayed up the nose has live flu virus in it. But, and it’s a big-sized but, the virus in this vaccine is weakened to such an extent that it can’t make you be sick.

So there we are.

The flu vaccines protect many people. Getting vaccinated is a good idea, and one you should discuss with your provider.

To help prevent infection, get vaccinated as we discussed, and keep your hands clean all day. Try not to touch your mouth, nose, or eyes with hands that might not be clean. Those areas are prime spots for disease transmission.

See you on the other side of cold and flu season!

 

 

by Trish Parnell





Flu and the drifting virus

5 12 2014

HiResWe get immunized against flu every year. It’s annoying, but the strains or types of viruses that cause flu are constantly changing, so the vaccines have to change.

Scientists track the viruses and figure out what will be dominant each year, and they keep those in mind as they concoct the vaccines.

This year, as has happened in the past, one of the dominant strains “drifted.” Over time, it’s changed enough that now the vaccines won’t protect against it because they no longer recognize it.

No one realized this strain that had drifted was around until this year’s vaccines had already been produced.

The vaccines we have will protect against a chunk of flu viruses floating around, but not this one. Which means, if you’re unlucky enough to become infected with this particular strain of flu virus, you’ll need to get into your provider ASAP if you have flu symptoms, such as:

  • Fever
  • Cough
  • Body or muscle aches
  • Chills
  • Runny or stuffy nose
  • Sore throat
  • Diarrhea
  • Vomiting

Your provider will put you on antivirals, which will help your body fight the infection. You need to get started on antivirals within a couple of days of symptoms appearing.

Don’t mess around with flu. It sounds like an old-timey illness that doesn’t mean much these days, but based on reports covering a 30-year span from 1977 to 2007, CDC estimates that, in any given year, there are between 3,000 and 49,000 flu-related deaths.

In addition to immunizing, make sure family members are cleaning their hands many times each day. The areas in the home that are frequently touched, like doorknobs, desktops, remotes, and faucets should be disinfected daily.

Keep your hands off of your eyes, nose, and mouth. Our hands pick up germs which enter our bodies when we rub our eyes or touch our noses or mouths.

Protect others by covering your coughs and sneezes, and stay home if you feel ill. Well, stay home AFTER you visit your provider.

That’s about it for flu right now. If you have questions, call the office or drop a line in the comments section.

 

By Trish Parnell





EV-D68

8 09 2014

There’s a virus in the US that’s sending kids to the hospital. Symptoms are similar to a severe cold. The virus is called human enterovirus 68 (EV-D68).

This virus affects the respiratory system, which is made up of the organs and tissues that let us breathe, including our airways (nose, mouth, windpipe), our lungs, and many other bits that work to keep us breathing.

EV-D68 was not a common culprit of respiratory disease until about 2009. That’s when the virus started to be identified with outbreaks in different parts of the world.

There are many strains or types of enteroviruses, and they are frequently the cause of our colds. This particular strain, EV-D68, is causing colds, but there are an unusual number of hospitalizations with this infection. Symptoms include coughing and difficulty breathing, which is what’s sending some people to the hospital. In addition, some people may have wheezing, a fever, or rash.

Those with existing respiratory issues, such as asthma, may find their symptoms more severe, as they do with any respiratory infection.

IMPORTANT POINT: This virus isn’t typically life-threatening, and although some who are infected will find themselves battling severe symptoms, most will experience only a mild cold.

There’s no vaccine available. We need to do what we always do to prevent colds—clean our hands throughout the day and keep our hands off of our face, as germs enter through our nose, mouth, and eyes. If someone offers you a bite of their spaghetti or a drink of their soda, politely refuse. Get your own spaghetti and drink.

And CDC reminds us that it’s important to disinfect surfaces (doorknobs, keyboards) to zap those germs where they sit.

It’s scary for parents to hear about kids being hospitalized, but if we practice basic disease prevention methods, we’ll help our families avoid this and other viruses that cause colds.





Here Come the Germs!

24 09 2013

I love my kids. I do. But, may I just say, entre nous, that my heartbeat slows and I’m immersed in a narcotic sense of freedom when they toddle off to school each September.

That euphoric bliss lasts about two weeks. Maybe. Then come the colds, the aches, the lethargy, the sniffles, the who-knows-what.

Does your family experience the same thing? Here’s what’s going on:

  • In the US, kids under 17 years of age experience over 50 million colds each year. M-m-million!
  • Kids miss almost 22 million (there’s that “m” word again) days of school due to colds.
  • Diarrhea is no slouch when it comes to affecting the health of our kids—it’s a big contributor to missed school days.
  • Bacteria and viruses can survive on desktops, doorknobs, walls, water spigots, cafeteria trays, shoes, backpacks, purses, and other surfaces for minutes or even hours. A few even longer, depending on the environment. The germs lurk on surfaces, waiting for unsuspecting hands to slide by and pick them up.
  • Some kids and teachers don’t cover their coughs and sneezes, and they don’t clean their hands when it’s important to do so. Depending on the germ, it may float in the air and wait to be inhaled, or drop on a surface and wait to be picked up, or transfer from germy hands to surfaces or the waiting hands of others.

What can we do? We can’t completely protect our kids from the germs in the world (and there’s no way I’m homeschooling), so we teach them how to protect themselves and live with the fact that they’re occasionally going to pick up germs. Picking up germs is not a bad thing. That exposure helps strengthen the immune system and does other good things for the body that are best left to another blog post.

To keep illness down to a manageable level, share these tips with your family:

  • Wash hands with soap and water after coughing, sneezing, playing inside or outside, going to the bathroom, or touching animals, and before preparing or eating food and at any time that the hands look dirty. And, wash those hands as soon as you come home from school or, well, anywhere.
  • Use hand sanitizer in place of soap and water if no soap/water is available, but soap and water are preferred. Remember that hand sanitizer kills many germs, but only while it’s being rubbed onto the hands. Once it’s dry and the hand touches something germy even two seconds later, germs will live on the hands again.
  • Cough and sneeze into the crook of the elbow. Coughing and sneezing into tissues is OK, but not ideal. The tissues are thin and the germs blast right through onto the hands, requiring an immediate hand cleaning. Plus, the germs are more likely to escape the tissue and float around waiting to be inhaled, or drop onto surfaces, waiting to be touched.
  • Don’t share with others anything your mouth touches. This means don’t share forks, spoons, water bottles, food, drinking glasses, straws, lipstick or any other makeup, come to think of it, and don’t use anything that’s touched another person’s mouth, such as their pen or pencil or any item already listed. This is not a complete list, just one to get you thinking about how germs can be passed from one person to another.
  • Keep your hands away from your eyes, nose, and mouth, as these are entryways for germs.
  • Walk around your home with a disinfecting wipe and clean doorknobs (interior and exterior), light switches and the wall area around them if the wall surface will hold up to the moisture, keyboards, remote controls—anything around the house that gets touched a lot.
  • Call your provider and your child’s provider and make sure the entire family is up-to-date on immunizations.

Share your tips in the comment section. Let’s try to have a healthy school year!

 

By Trish Parnell

 

 





Sports and Infectious Disease – Part 1 of 3

6 04 2013

exeterIf you coach a little league team, parent an active athlete or are an avid sportsperson yourself, it is important to know what health risks may be present during athletic events other than shin splints and bruised egos.

Close physical contact and a heightened chance of bleeding present a chance for disease transmission unless appropriate precautions are taken.

Athletes, trainers, coaches, parents, and teachers alike must know how to prevent the transmission of bloodborne viruses such as HIV and hepatitis B or C, or even skin-to-skin infections.

These infectious diseases, and others, pose complex problems for athletes of all ages and everyone involved in sports activities.  But following standard precautions to prevent bloodborne, skin-to-skin, and respiratory infections simplifies and safeguards sports events and ensures that everyone can participate safely.

Sports and Standard Precautions

Universal use of standard precautions is critical because many children, adolescents, and adults who are infected with viruses, such as HIV and hepatitis B or C, may not even know they have these viruses.  Estimates vary, but some predict that more than half of those infected with these viruses do not know they’re infected.

Standard precautions protect everyone, from those whose diseases have been identified, to those that have not yet been diagnosed, to those not infected.  When everyone follows standard precautions, no one who has an infection needs to be treated differently.  Essentially, standard precautions are the great equalizer; when followed, they allow everyone to fully and safely participate in sporting events.

The more serious bloodborne viruses that athletes need to be aware of are: HIV (the virus that causes AIDS), hepatitis B, and hepatitis C.  There is no recommendation that people infected with these viruses not be allowed to participate in most sports.

Although HIV and hepatitis C are not vaccine-preventable, there is a safe and effective vaccine that prevents hepatitis B infection.

Skin-to-Skin Infections

According to the NCAA Injury Surveillance System, “skin infections accounted for almost one-third of the practice time loss events” in wrestling during the 2001-2002 season.  As a result, the NCAA recommends that coaches, teachers and other sports officials be able to identify symptoms of skin infections.  Symptoms may include:

  • Crusting
  • Scaliness
  • Oozing lesions

Skin infections may include:

  • Bacterial skin infections including impetigo, erysipelas, carbuncle, staphylococcal disease, folliculitis and hidradenitis suppurativa.
  • Parasitic skin infections including pediculosis and scabies.
  • Viral skin infections including herpes simplex, chickenpox and molluscum contagiosum.
  • Fungal skin infections including ringworm.

In some cases, such as fungal infections, the skin conditions can be covered with a securely attached bandage or non-permeable patch to allow participation in the sporting event.

In addition to identification and treatment of individuals with skin infections, prevention can occur through proper routine cleaning of all equipment, including mats and shared common areas, such as locker rooms.

Respiratory Illnesses

Anyone with an infectious respiratory illness, such as flu, or whooping cough, or perhaps tuberculosis, should be prohibited from playing to prevent the spread of infections that are transmitted through respiratory routes.

Check back over the next couple of weeks for Parts 2 and 3 in this sports series. Part 2 gets into specifics on bloodborne pathogens, and Part 3 provides guidelines for sports teams to follow before, during, and after each event.

 

See PKIDs’ Infectious Disease Workshop for more information.

Photo courtesy of University of Exeter





The Trouble With Some Microbes . . .

7 02 2013

Our battle against bacteria is tilting in our favor. After all, we have vaccines and antibiotics on our side. That doesn’t mean we can get cocky. It’s tilting, not surrendering at our feet.

But we’re still struggling to find ways to kill viruses once they’ve infected us.  At best, we can sometimes control them.

Although we can kill viruses on our bodies and other surfaces with disinfectants, it’s difficult to kill them when they’re living inside our cells.  When we’re infected with a virus, it takes up residence in one of our cells and uses the cell’s machinery to reproduce itself.

Developing a drug that will kill the virus without disrupting the intracellular machinery of uninfected cells is no easy task. It’s like playing Jenga—eventually the whole structure will collapse.

Bacteria, on the other hand, generally live outside of our cells and are easier targets.

There are some bacteria that have developed a resistance to not just one drug, say for instance penicillin, but to many such drugs.  They’re known as multi-drug resistant microorganisms such as streptococcus pneumoniae and mycobacterium tuberculosis, germs that we thought were very much under control and are now surging back into the population.

One major factor in preventing us from understanding the world of microbes is the size of that world.

The folks at the University of Georgia College of Agricultural and Environmental Sciences put bacteria into perspective this way, “Bacteria vary somewhat in size, but average about 1/25,000 inch.  In other words, 25,000 bacteria laid side by side would occupy only one inch of space.  One cubic inch is big enough to hold nine trillion average size bacteria—about 3,000 bacteria for every person on earth.

“Bacteria make up the largest group of micro-organisms.  People often think of them only as germs and the harm they do.  Actually, only a small number of [the thousands of different] bacteria types are pathogenic (disease-causing).  Most are harmless and many are helpful.”

Neal Rolfe Chamberlain, professor at the Kirksville College of Osteopathic Medicine, explains viruses in this manner, “Viruses are very small forms of life.  In fact, people still argue over whether viruses are really alive.  Viruses range in size from about 20 to 300 nanometers (nm).  A nanometer is 0.000001 of a millimeter.  A millimeter is 1/25 of an inch.  So in other words, you can place 25,000,000 nanometers in an inch.  If the biggest virus is 300 nm then you could fit 83,333 of that virus in an inch.

“Viruses are major freeloaders.  They cannot make anything on their own.  To reproduce they must infect other living cells.  Viruses infect bacteria, parasites, fungi, plants, animals, and humans.  No one escapes them.  If you have had the flu, chickenpox, measles, a common cold, mono, a cold sore, or a sore throat you have been infected by a virus!”

Some viruses, like HIV and hepatitis C, tend to develop strains that can resist mono drug therapy (treating the patient with one drug at a time).  We have to try and control the viruses with combination, or “cocktail” drugs (treating the patient with several drugs at once), although even that approach does not always work.  Some viruses can keep mutating until we’ve run out of drugs to try.

All this is to say that fighting microbes is seldom a simple task, and seemingly one that is neverending. For example, we have a whooping cough vaccine, but new strains are popping up and new vaccines are needed for this astoundingly infectious microbe.

We will never be rid of our tiny co-inhabitants on this world, and anyway, most of them we want to keep around. It’s those others . . . wouldn’t it be nice to have a jail for nasty microbes?

By PKIDs’ Staff





Antibiotics and When to Use Them

30 07 2012

Summer has its share of illnesses, but for most physicians, the “illness season” begins to ramp up in the fall. Colds, sore throats and ear infections, among other illnesses, are much more common.

Patients come to the doctor’s to get better, and for many years that has meant leaving the office with a prescription for antibiotics. Many illnesses were treated unnecessarily, and as a result, antibiotic resistance has increased.

Antibiotics first came into widespread use in the 1940s and revolutionized medical care. Bacterial illnesses, such as pneumonia, strep throat, bladder infections, etc. could now be treated. Within a few years, however, bacteria resistant to penicillin were already present.

Antibiotics kill sensitive bacteria, but resistant ones can survive and multiply. Through the years, antibiotics that used to work for infections become less effective.

While antibiotics work against bacteria, they do not treat viruses. Viruses cause the majority of infections (colds, many sore throats, influenza, most coughs). In many cases, however, antibiotics are prescribed for viruses. This leads to increasing bacterial resistance.

Why are antibiotics overused? The answer is multi-fold. Parents often come to the office with an expectation that they will be given something to make their child better. Doctors want to help people.

In the early years of my practice, it was common to treat for an “early” ear infection, or sometimes, “to head off the illness.” Our knowledge of the natural history of illnesses has advanced. We used to think that if a cold produced yellow or green drainage, this was an indicator of sinus/bacterial infection. Now we know that discolored drainage is a normal part of an illness that may last 10-14 days. Some ear infections will clear up on their own. Sore throats that are not caused by strep do not need an antibiotic.

When antibiotics are needed, the most specific antibiotic is best. Some antibiotics are “broad spectrum.” They kill many bacteria, not just the ones causing the infection. Many of these are newer antibiotics, and while they might be more convenient, taste better, etc, they may be more than is needed, hastening antibiotic resistance.

The advantages of using antibiotics wisely are many. Short term, there will be fewer side effects (diarrhea, rashes, stomach ache), and long term, hopefully, when antibiotics are needed for a serious bacterial infection, they will be more effective.

So, when your doctor says, “Good news, they don’t need an antibiotic,” it really is good news.

By Dr. Katherine Vaughn

Image courtesy of AJC1





Ask Emily

26 04 2012

What’s the deadliest infectious disease ever and what currently is the most deadly infectious disease?

The answer to this question is more complex than simply counting up numbers of people who die from infection. For example, diseases like measles and smallpox have proved to be far deadlier in some populations—such as Native Americans—than in others, because of population differences in disease resistance.

Another variable is intensity of the illness a pathogen causes. Influenza comes in many forms of virulence, and as the Spanish flu pandemic of the early 20th century made clear, even that virulence can vary depending on specific population features; the Spanish flu, which took an estimated 50 million lives, killed the young most relentlessly.

Even an individual disease vector can wax and wane in terms of how virulent it is or which tissues it invades. For example, Yersinia pestis, the bacterium responsible for the infamous Black Death that swept through Europe in the 14th century, may vary over time in its virulence and is far more deadly when transmitted as an aerosol to lung tissues than when it invades the lymph and causes the bubos that characterize it.

Another issue is, how do we calculate “deadliest?” Is it in terms of sheer overall numbers, or do we calculate it in terms of how many people it kills among the number infected? For the sake of addressing this question, let’s talk about both.

Historically, in terms of sheer numbers, the deadliest diseases were smallpox, measles, tuberculosis, plague (e.g., the Black Plague), and malaria. According to a handy Website, the Book of Odds, which calculates odds for us, measles has killed about 200 million people worldwide in the last 150 years and still kills hundreds of thousands in the developing world. Thanks to vaccines, the odds of contracting measles in the United States today are very low unless you are an unvaccinated person living in areas where vaccine uptake is low.

The story on smallpox is similar—it may have killed more people by percent or sheer numbers than any other infectious disease in history, including 300 million in the 20th century alone by some estimates. Yet smallpox as an infectious disease no longer exists thanks to its total elimination through vaccine campaigns.

Thus, along with the plague, smallpox and measles have, for millennia, been the historical killers of humans and would still be among the deadliest infectious diseases today were it not for vaccines. What we have left are some old killers on the list—tuberculosis and malaria—and a newer entity, HIV, the virus that causes AIDS.

We have yet to develop efficient vaccines against any of them. According to USAID, in terms of absolute numbers of deaths, AIDS kills the most people each year, with 2.8 million AIDS-related deaths in 2004, followed by tuberculosis and malaria.

Indeed, AIDS and tuberculosis are often co-conspirators in death, as infection with the HIV virus makes people 20 to 30 times more likely to develop active TB with TB infection. Research for vaccines against HIV and malaria has been feverish but as-yet incompletely successful, one reason these diseases remain the top global killers.

But what about the deadliest disease in terms of how many of infected people die? In the absence of effective treatment, HIV might be one candidate. But the ones that come first to mind are the viruses that cause fast-moving hemorrhagic fevers, such as the Marburg or Ebola viruses.

The Marburg virus, named for the location of the first outbreak and a virus that may reside without symptoms in fruit bats, has caused death rates as high as 90% in some areas, although the average is 23–25%. It is a filovirus, in the same viral family as the five Ebola viruses. One of the Ebola viruses, Ebola-Reston, is perhaps the most notorious of the hemorrhagic fever viruses, having led to death rates as high as 89% in outbreaks.

A near-100% mortality rate is about as deadly as an infectious agent can be if that’s the measure of “deadly” we’re using.

By Emily Willingham

Image courtesy of Wikimedia Commons