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Daniel Streicker / ASTMH Press
Vampire bats in an abandoned mine in Huanuco, Peru. Researchers are investigating whether some Amazonian villagers may have survived rabies infections, which have a nearly 100 percent fatality rate.
Some Amazonian villagers plagued by vampire bats may have survived rabies infections — something that doctors thought was virtually impossible. The scientists' discovery opens hopes of eventually developing an effective treatment for the nearly always fatal infection.
A study of people living in remote areas of Peru shows that about one in 10 appears to have been bitten by rabid bats, but lived to tell the tale. Rabies is almost universally fatal, with only five documented cases of people surviving. Teams at the Centers for Disease Control and Prevention are now looking further to see if people may survive the deadly virus more often than had been believed.
“They were infected,” said the CDC’s Brett Petersen, an epidemiologist who worked on the study. What’s not clear is whether the people who survived infection ever actually got sick.
Any mammal can get rabies, and the disease causes horrible symptoms as the virus attacks the nervous system. It can make an animal aggressive and violent and can cause severe pain. Victims eventually fall into a coma and die when they can no longer breathe properly.
“Rabies has the highest case fatality rate of any conventional infectious disease, approaching 100 percent,” Petersen and colleagues wrote in their report, published on Wednesday in the American Journal of Tropical Medicine and Hygiene. People can survive if vaccinated immediately after a bite or other exposure to rabies, but there is no real treatment for infection, with very rare exceptions.
The CDC team and officials with Peru’s health ministry traveled to a remote Amazon region where vampire bats regularly feed on cattle and people. It took two days to reach the area by boat.
“Many of [the people] have very basic housing. There are no real barriers for entry to bats. The bats are able to enter the house and have easy access to people,” Petersen said in a telephone interview. The teams interviewed 92 people and got blood samples from 63 of them.
More than half said they had been bitten by a bat at least once and 20 percent said they were bitten more than once a year. The blood tests showed something startling -- seven people, or 11 percent of those tested, had antibodies against rabies. These immune system proteins were the type that can neutralize a virus.
“This shows evidence that these people were exposed to rabies virus previously,” said the CDC’s Amy Gilbert, an epidemiologist who led the study.
It's undetermined whether these seven people had actually become sick. Early symptoms of rabies infection aren’t always clear and can resemble those of a cold or flu. The incubation period can be as long as three months. It might be, Gilbert said, that they were bitten and got a very low dose of the virus, perhaps not enough to make them sick. More study will be needed to find out.
“We know that not all viral introductions into the body will lead to clinical illness,” Gilbert said. A lot depends on how much virus gets in, what part of the body, how deep a bite was, and perhaps if other germs got in at the same time.
What is certain is, rabies is very deadly. “We are still talking about 99.999 percent of cases, approaching 100 percent,” Gilbert said.
The scientists aren't sure the villagers are actually immune to rabies, so the CDC team is recommending that all get vaccinated.
“What we know is that they did develop an antibody response. We don’t know what level of antibodies will provide complete protection,” Petersen said.
More outbreaks of rabies have been reported in the region in recent years, he added.
Rabies was once a global scourge, but widespread vaccination has made it very rare in countries such as the United States. The vaccine is very effective if given before symptoms develop. That's why doctors urge anyone bitten by an animal get medical attention right away. Most US cases – and there are just one or two a year at most – are caused by bat bites.
Globally, the World Health Organization says 55,000 people die of rabies every year, with dogs the source of 99 percent of these fatal bites. Five people have survived documented rabies infections -- all young girls who were given a complex treatment called the "Milwaukee protocol," which involves putting them into a medical coma.
"Our results open the door to the idea that there may be some type of natural resistance or enhanced immune response in certain communities regularly exposed to the disease," said Gilbert. "This means there may be ways to develop effective treatments that can save lives in areas where rabies remains a persistent cause of death."
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Leave a Comment:
Wow. Globally 55,000 per year. I had no idea that so many people die from rabies.
My Question
Do they become potential carriers of Rabies?
No. Rabies is only transmitted during the acute stage.
I guess I'm safe then, I've never had a cute stage...my mom said I was even an ugly baby...
I guess I should have been more specific...does the immune systems in question prevent the desease or destroy the virus?
Both.
55,000 out of 7+ billion is nearly nothing
What the Rabies Virus really needs is a new vector...just a couple of mutations away...
Bat sh*t cray
If Anne Hathaway were a real bat woman, I'd let her bite me all day long
my daughter was been by a bat and went to er. they didn't even wash the site..just gave her antibiotics..how stupid is that,, myself and my other daughtr called health department.. and the next day she got the vaccines she needed. but what if?
You should report the hospital to your state's health services. If you live in California, call California Health Services and make a report.
And I'd call a malpractice attorney.
Sure...Then maybe the daughter can call an attorney and sue her mother for neglect because she got bit in the first place.
Also...your first two sentences are repetitive. They say the same thing.
Who thinks Robin is smart enough to see what I did there?
Maybe the hospital did not believe you. Maybe it looked NOTHING like a small mammal bite.
Did you SEE her get bit?
I don't mean to be a jerk but your story needs some fillers before I get all "angry citizen".
Unlike Robin Reich....I'm thoughtful.
This is unfortunately too common. I work for the Health Department. We got a patient a while back who had been bitten by a raccoon. He went to the local ER. He was told by the nurse practitioner that the bite wasn't deep enough to worry about rabies. Wrong. He came to us on Monday morning. We administered the rabies vaccine series to him. I contacted the infection control nurse at the hospital, she reviewed the chart, and the practitioner who treated him received a written reprimand. Even a small scratch can transmit rabies. A bite from a bat can be so small as to be invisible. Their teeth are tiny and needle sharp. If someone tells you that they have been bitten, you take no chances, you believe them.
good for you to persist and call health dept...maybe you saved her life
hospital might have cost it
definetly be sure this hospital has consequences...or some other person might die
There are many more cases of bat bites in the U.S. than this article says. Just here in Southern California alone we've had several cases of bat bites so far this year. One of the bites came from a vampire bat that came up from Mexico. The others were a bat from a Long Beach park flew in a window and bit someone. The other one was in a home that was being tented for bugs. The bats were in the roofing tiles and when the exterminators tented the house the bats flew out into the tent. When they came to remove the tent the bats flew at them. All the bats had rabies.
Bats serve no useful purpose and should be exterminated.
"Bats serve no useful purpose and should be exterminated"
Actually, bats are natural insecticides. Farmers around here build bat boxes by their farms so the bats will eat the insects off the plants. When the bat population starting dying off due to an unknown fungal disease, it was a huge issue for farmers who had relied on them for killing the insects without chemicals. I agree that bats carrying rabies is an issue, but all living things serves a purpose in the ecosystem. You can't go and kill an entire species off- it upsets the ecosystem.
Robin,
Bats eat mosquitoes. Mosquitoes kill many more people then bats. I have quite a few bats flying around my house at night and I have never had a problem.
What an uneducated comment!
I'd rather have some bats flying around than deal with all the insects that would be left if there were no bats. Bats can eat up to 600 insects per hour feeding for 4 to 6 hours a night. How long would it be until you started complaining about malaria-carrying mosquitoes if there were no bats to help control them and other insects? How much would you whine and complain when crops are destroyed becuase there were no bats around to eat the crop-destrying insects?
Some bats also have a blood thinning chemical in them that is used to treat stroke patients and others that may need it.
Bats help with pollination and their guano (poop) is great for plants and trees.
I'd list more things, but you should be smart enough to use Google on your interwebs box.
Robin Reich,
Your the kind of person that can be so harmful to the ecology of the planet.
EVERY creature has a purpose. Robin Reich (thankfully) is not the judge of who stays and who goes.
Bats eat insects. Insects defend territories by infecting invasive marauders. (Malaria saved much of Africa from the Roman Empire) blah, blah, blah.
People hide this information in things called books. Google it.
Robin. that is an abysmally ignorant post. Bats are one of the most important natural insect controls in nature. Decimation of the bat population is always looked upon by farmers, ecologists, and scientists as a serious crises when it occurs. Interactions with humans are quite rare, in the US. Also, I am quite sure that "all of the bats" in a colony were rabid. That incident would have made national news.
bats also act as pollinators, and fruit bats are vital to the reproductive cycle of some fruits- bats eat the fruit, their digestive tract strips the hard, impermeable surface from the seeds allowing it to sprout and poop the now ready seeds across the land. this demonization of the natural world needs to stop. im sorry it makes you scared but we are wild animals who are a part of the ecosystem, sometimes strange scary things happen, sometimes people die- that is life everyone will die one day
it is very ignorant to conclude any living thing serves no purpose, as you did, without really knowing.
you are so wrong with bats...for example
they keep insects under control...for one thing. without them we'd be overrun by insects...not fun
This article really didn't say it but my understanding was that even if you are bit by a rabid animal, your chances of getting rabies are relatively low (even without the vaccine). I read somewhere that it's really only like 15 percent, and a lot of it depends on your own immunity as well as where you were bit (getting bit on the hand is better than say the neck) and how deep the bite is. I'm not sure how true this is as I read it on the internet, but even if it is true, if I ever got bit by a wild animal I would definitely get the shots. Better to be safe than dead.
And @Robin Reich, I totally agree. In Colorado, we have quite a few people who are bitten by bats. We also have recently had an outbreak of horses with rabies. They think they got it either from bat bites or skunk bites.
my understanding is that few people have immunity
it depends more on the dose of virus you receive in the bite if the bad is infected...and that has to do with the depth and location of the bite as well as the amt of virus in saliva of the bat, which is linked to the viral load in the bat
In the other parts of the world (Europe,Asia) where vampire bats are not living, the main reservoir of the rabies are wild animals, especially foxes. Foxes are vaccinated once yearly by special atractive sandwiches which are spread in areas where foxes live by hunters or by means of airplanes. (England & Ireland are known to be free of rabies). Import of tropical vegetables&fruits can bring with also vampire bats.
In Guyana (late British colony), on a farm in Mazaruni prison complex I have seen wounds on the pigs, caused by vampire bats. They look very bad.
How could you fail to mention Jeanna Giese from Fond du Lac, WI? She is the only person KNOWN to have survived rabies. Look up the story.
She is one of FIVE known to survive.
Did you read the article?
Yes. I read the article. She is the only one who survived who did not get rabies shots before OR after she was infected.
Yes, There was a young girl not long ago in Wisconsin that survived.
I had to take the rabies shots, I was young and I think I remember taking around 10, one each day. I recently got a pet skunk and the vet said that I should have blood work done to ee if I still had antibodies in my system. I will say this, if you think you have been exsposed get the shots, they are not that bad and they don't give them in the stomach anymore.
Rabies is almost 100% fatal after showing symptoms, it is the most fatal disease on the planet, I think there have been a few survivors of this horrid disease.
I work in animal rescue. Some years back I was bitten by a cat that died not from rabies, but pneumonia after a two week quarantine. The vet decided to take the head and examine it on a feeling. The cat was rabid. I was already past the date for vaccine when the health department notified me. Instead of injecting into the wound they started pumping in the shots. I was very sick from them, but survived. The vet kept calling me and later I asked her why so many calls. She responded, "They didn't believe I made it through it."
There is so caled "arctic rabies" which is not fatal to humans. It was described, for example, by Dr Goldman in 1855, in Yakutia region of Russia.
It's possible those bats had the same kind of virus.
People who survived "arctic rabies" were supposedly also immune to "real rabies".
How did the arctic rabies virus get to the amazon? Is it originally from the amazon? Would they both be milder strains of the rabies virus? It's a possible theory, and it makes sense that the weaker virus helps with immunity to the more deadly virus, however I cast doubts that they are both the exact same virus unless testing is done.
First, bats are useful and wonderful animals. However, bats do not make much of a dent in the mosquito population. A mosquito is so small that to a bat it is like a regular M&M is to us. A treat, not a meal.
Second, there are many strains of the rabies virus. Some of them are more virulent to humans than others. Humans are really rather resistant to most rabies strains.
Third, not all mammals are equally susceptible to rabies. Marsupials, rodents, and lagomorphs can contract rabies, but they rarely die from it or pass it along in their saliva. Thus if you are bitten by an opossum, rat, or rabbit, you do not have to worry about rabies.
Fourth, the rabies virus propagates through nerve tissue. If the immune system does its job, the virus will be destroyed before reaching the central nervous system. Once rabies infects the central nervous system (brain/spinal cord), death is almost certain.
Fifth, rabies virus propagates through nerve tissue and so a bite which results in an infection in an extremity (hand or foot) will take weeks or months to reach the central nervous system. Treatment is most urgent for people bitten on the face and next for other areas of the head or neck.
Because rabies is such a deadly disease, all people who are bitten by mammals that are known to transmit the disease must receive prophylactic vaccination.
I am a retired public health official.
I found a newspaper from 1991 while I was cleaning our camper. An interesting tid bit of info was written in an article about how there was new technology being developed to treat a disease, and it would one day open the door for a potential cure. I can't think of what the disease was now, and sadly I threw the newspaper away. I still thought it was weird though that still today it's as harmful of a disease as ever. If I remembered what it was that would be nice..
On a side note, I just backed my truck's hitch into the front bumper of my car... Starting now, I'm going to be a nicer person.
Another rabies survivor..I knew his son..
link wouldnt post
One has to wonder whether it is something in the indigenous people or something in the bats that allow them to survive a bite from a rabied bat. Maybe we could get some tea party types to go down there and volunteer to do something really patriotic and get bitten by the rabied bats and see if they survive.
I read something years ago (30 or more) about a man who survived rabies. They had to treat each of his symptoms separately, instead of one general treatment, but it worked.
The "Milwaukee protocol" refers to the Giese case, since it was the first time anyone who had NOT received shots was saved from a full blown case of rabies. The protocol had never been used in this situation before. Milwaukee is where she was hospitalized. It is 60 miles from her (and my) hometown, where the bat bite occurred.
@aggrevatedofficeworker...55,000 out of 7 billion is nothing unless you are one of the 55,000 every year affected....
Maybe the south american survival rate was high because they are now zombies (from vampire bat bites)!!
robin reich, you don't like bats because you live in a bat cave......admit it!
Actually, bats are terrific at tracking and consuming many thousands of insects a night.