Biologist here: Bats don't carry these viruses because they're particularly unclean or anything like that. They actually transmit them because they often have exceptional immune systems that can keep them alive even though they're infected, which unfortunately gives more opportunities for a virus to spread.

CJD is tragic. My girlfriend’s uncle suddenly went blind completely out of the blue one day, and literally 14 days later, he was dead. The day before he died, he was diagnosed with CJD, and passed not even 24 hours later. In that time he developed dementia at such a scary rate, I think it was after a week he no longer recognised my girlfriend (his niece, obviously.) It was completely unexpected, and just as tragic. No one is sure where or when he got it, but I think there were assumptions it was several decades ago, so it was a case of a very long dormancy period.

Welp, there goes my plan for a global chain of exotic bat petting zoos. Thanks alot SciShow!

I'm an Aussie, and used to rescue flying foxes (fruit bats) from barbed wire fences etc. I never acquired Lyssavirus, even though I received a few scratches and bites over the years. I started wearing gloves after the virus was discovered, and the source was ascertained.

Poor Savannah was *so* grossed out by the whole Guinea worm thing and I am right there with them.

"Ebola's bigger, meaner cousin" Now there is something to induce nightmares ...

Reference lab worker here. We get a CJD sample weekly. Typically a rule out, but they have been positive. We double glove and double bag those ones. Stay safe folks.

My dad nearly died from Rocky Mountain Spotted Tick Fever around 35 years ago. He initially spent a week in the hospital. It caused permanent damage to his liver which later caused additional hospitalizations years after the fact.

Please don't hate on bats, its not their fault and we need them more than they need us.

Do tick checks and tuck pants in socks. Check! Don’t touch bats. Check! Boil your water. Check! Don’t eat British beef. Check! Don’t go out in a dust storm. Check! I feel safer already.😂

*Now for around the world in 81 diseases.*

I was momentarily distracted but soon as she said “John Green” I immediately knew they were saying something about tuberculosis.

Valley Fever is endemic in the San Joaquin Valley of California. I know several people who were infected and one landmark, Shark Tooth Hill, has been closed for decades.

"Take a hike, guinea worms!" That seemed heartfelt🤣

I use to do BSE testing. Prions diseases are scary stuff!

"Fun" fact about variant CJD: the outbreak was largely caused by, what else, crappy UK food safety and animal welfare regulations! The huge BSE outbreak in the 80s and 90s was traced back to the delightful British farming practice of... feeding cows with (amongst other things) ground up dead cows (it's literally called "Meat and Bone Meal", or MBM) to try and improve milk yields. It worked (basically by increasing the amino acid intake of cows)... but caused a huge BSE epidemic in the UK, which is largely how it was localised here and why all the vCJD cases are clustered strongly around the UK. Turns out, if you get _one_ case of BSE, and then casually grind that cow up and feed it to the rest of your cows, then congrats: the rest of your cows all have misfolded proteins (i.e. BSE) now, too! Thankfully feeding ruminants MBM is banned basically worldwide now, although apparently it's still used in monogastric animal feed? I still remember as a super young kid growing up in the very late 90s and early 2000s occasionally seeing like,,, troughs of disinfectant that you had to walk through to get to various places, to avoid the spread of "mad cow disease" on your shoes or w/e (EDIT/CORRECTION: it's been pointed out that I was mixing mad cow disease up with the foot and mouth disease outbreak which happened in 2001, my bad! Although tbf I was like... barely more than a toddler at the time lol. thanks to @WingedAsarath for pointing that out!). Once the link was made to feeding cows MBMs, you can imagine how many headlines along the lines of "Soylent Beef" got run in various newspapers :P

"Bat infested cave" feels unfair to the bats, they're just chilling in their home

Once again, New Zealand is left off the map (0:17). 😂😂 We are real, we do exist.

Ticks can be active all year long. Last year in February, I got a tick bite. I got sick for 24hrs, but never had any rashes, just bad headaches and nausea. I was lucky because here in Missouri, a tick has killed a state park worker, couple of years ago, which caught a lot of attention in the news. What's scary is we were there the same time she was but none of us got bitten. Thank goodness!

I had a chemistry lab partner who had survived Valley Fever. He developed endocarditis. He showed me a news article about himself (his case was notable due to the severity and the fact that he was not in the typical demographics for Valley Fever patients)

I live in Australia and I don't think I ever realised before this video that Lissa virus is similar to rabies. I just knew to stay away from bats 🦇

Marburg may be spread by bats, but it's not exclusive to them. At least one outbreak was carried by monkeys.

As a Washingtonian, yes, Valley Fever has been detected in the state, on the warm, dry, eastern side of the state. The parts that are similar in climate to the San Joaquin Valley of California, where the disease is also endemic. Showing imagery of the western part of the state (those bridges are in Tacoma, Washington) is at best ill-informed, and at worst downright misleading. Is it a disease we should keep an eye on, including avoiding spreading its habitat through climate change? Yes. Is it something to freak out over that Seattle is about to be in danger? No, at least not yet.

I was diagnosed with rocky mountain spotted fever at 4 years old. I visited my aunt in Chambersburg Pennsylvania, rode a pony that came from out west, and almost died until a doctor figured it out. The doctor had worked in Colorado, and until the test results came back, no one believed him. I am alive 38 years after a 106 degree fever.

My ex got Valley Fever while we lived in Tucson, and he was real, real sick. In the hospital for days, could hardly breathe.

"People don't usually bring bats home as souvenirs" *Bruce Wayne has entered the chat*

"Bat-infested caves"? No way, they live there! Those are *human-infested* caves.

_pats bat_ "this bad boy can fit so many diseases!"

I contracted Valley Fever after working as an archaeologist in Phoenix. As a paleopathologist , it was fascinating; as patient, not as fun. I’m still dealing with problems related to the disease. Also, Disease and Human Evolution was my favorite class in college, though the parasites section, right before lunch, was difficult to digest.

"I do not believe that infectious disease is an enormous threat to human health." - RFK Junior, June 27, 2023 (that statement alone disqualifies him)

Just a quick plug for This Podcast Will Kill You. They’ve done an episode on almost every single one of these diseases.

Aussie here. We call the Australian Bat Lyssa Virus Hendra Virus. First discovered in horses in a Brisbane, QLD suburb called Hendra. Got transferred to a vet called in to work with the horses and his family.

My lab at Emory is doing research in ticks right now where we monitor the prevalence of Rickettsia rickettsii in ticks in Georgia by grinding them up and then testing the tick slurry for the bacterial DNA via PCR!

I had an aunt on a farm here in South Australia who died of CJD. It's likely she got it from eating the brain of a sheep that had scrapies (equivalent of BSE).

My father contracted rocky mountain spotted fever, here in Memphis,TN. He was hospitalized for more than a month before they actually figured it out. Definitely checks out.

I think there's a vaccine for the Aussie bat rabies but it's usually only given to wildlife rescue, zoo staff and anyone working with animals.

Well thanks for the future nightmares about worms.

My great aunt was one of very few Americans to get mad cows disease after a trip overseas. Because of that me and basically anyone who had prolonged contact with her through her life can never donate blood, just in case.

I contacted Valley Fever when i lived in Bakersfield, CA. I had flu symptoms for about a week, but a crazy little prolonged symptom or side effect was, I craved ketchup for more than a year. The cravings were crazy, like if there wasn't something on the menu in a restaurant that I would eat ketchup on I would get really emotional. I would liken it to the cravings during pregnancy (other people's disruptions), but I didn't have craving during pregnancy, so I'm assuming it was similar.

Rocky Mountain Spotted Fever survivor here, from central Virginia. Got lucky to have been seen by a doctor who had just gone thru a long, tedious diagnosis of another patient with the same problem. It is VERY hard to identify.

4:40 House M.D. viewer: “wait a second this sounds familiar…”

14:05 Is there anything in Australia that won't kill you. 🤣🤣🤣

There have been a couple cases of coccidiosis here in Oyster River in British Columbia, Canada. Nowhere near Arizona!

I work at a cat clinic in AZ, and valley fever is one of the things we routinely test for as the next step when a patient is losing weight and regular bloodwork comes back normal. It can be anywhere in the body, so the only symptom all valley fever kitties have is weight loss. And it can actually be transmitted from infected animals if it's in the skin, happens to be producing spores at the time, and you get your face too close to a lesion and breathe it in.

I lost a beloved dog to Valley Fever after my family took her on a vacation in Arizona. Because it's so isolated of a disease the vets back home had no idea what she'd contracted.

My bf's mom got RMSF from a tick in NY. After getting lyme twice.

To be fair to the valley fever, close to half of washington is high altitude desert, so its pretty dry and warm during the summer.

Ooooh the TB video was absolutely brilliant! I watched it yesterday and would highly recommend. ❤

Deer have a form of BSE and it's pretty common among whitetail deer in the US.

This was very informative and well presented. I won't be sleeping for a week.

Poor bats get such a bad rap because of their weirdly strong immune system D: but yeah staying away from them is still the smartest move : they get to live another day instead of going extinct, you get to live another day too, and we don't get back to confinement x)

Love Savannah’s videos. They do such a great job 🎉

Thank you Savannah. You honestly inhabit the narrative and make it real. Awesome!

thanks for the info!! You're awesome!

Australian here. Gotta say, bats are the LEAST of our concerns. They don’t ambush you on the toilet seat, they don’t jump out at you, they don’t… It’s easy to leave bats alone, and they return the favour. I’ve been below a swarm of bats at night. Amazing experience. And, by the amazing dexterous ability of NOT interfering with them in any way and staying on the ground, I had no problems.

Watched John's lecture. It was amazing.

This is really good. It would be cool if you guys did more videos to the effect of "here are some things that could kill you that you might not already know about."

I'm vaccinated against rabies specifically so that I the opportunity to work with bats in my capacity as a veterinary nurse ever arises I will be able to take the opportunity. I love bats!

I love how I knew about these from House :3

Marburg becoming airborne would be an unprecedented catastrophe.

I remember hearing about Valley Fever when attending college in central California around 2012/2013. We were told to use the car air recirculation button to reduce the chances of breathing it when traveling by farms. I’m sure that doesn’t have too much of an impact… but I’m still paranoid about it to this day.😂

Mad cow disease was found in NC last year at a slaughterhouse. The cow came cow came from TN. I’m not sure why nobody is talking more about this. Please do look this up.

Your message came through loud and clear - technologically and logically 👍

As someone who was born and lived in arizona for a decent chunk of my life and visit most summers, yeah, don’t drive with your windows rolled down unless you want valley fever or hayfever! Avoid the dust storms, and just generally be smart. Wash your hands. I live in texas, water here isn’t entirely safe where I live and we’ve gotten brain eating amoeba warnings! Boil water.

Kentuckian here. That range of Rocky Mountain Spotted Fever is way too close for comfort!

I remember being terrified of getting Rocky Mountain Spotted Fever back when I was in Boy Scouts in Alabama. Thankfully I never got it, or even met anyone who had it.

"Cutie Cute Host Horrifies Viewers" Alternate video title 🤓

I enjoy the way this presenter presents, she seems like such a sweetheart too.

I love learning about diseases and medicine and all related things - which is no surprise as I am a first year vet student....so cue my mix of horror/delight as you run through practically all the zoonotic diseases we have talked about between Virology and Microbiology so far. We even touched on Valley Fever- even though it isn't zoonotic. I really didn't realize until coming to vet school how many of our most serious diseases are not unique to us humans and how important a unified, One Health, model is for the future of medicine. Also I agree. DON'T TOUCH BATS.

This host is so engaging! I really like their vocal styling, I hope we see more of 'em!

Good video. Thank you.

8:30 Nipah was the inspiration for the fictional disease in the movie Contagion. Still one of my favorite movies of all time, even though it was uncannily prescient.

I just happened to be in London the week the whole "Mad Cow Disease" thing came out. That was in 1996. Knowing that it can have a decades-long incubation period, I wonder if, by now, I would've started showing symptoms. I'm not overly concerned, however, just an interesting "what if?"

I don't know how true it is, or whether I'm actually thinking of some other parasitic worm, but I recall learning years ago that the worm wrapped around the stick of Hippocrates is a Guinea worm.

Leave bats alone. Just leave bats alone.

Bats and ticks and worms oh my!

As someone who heard about Guinea Worm from what I think was a previous SciShow video from several years ago, my blood went cold when I heard the name again. I definitely looked away from the screen during that.

Wow - just did a mandated training on Valley Fever here at a transportation authority here in SoCal.

My friend (A bat scpecialist): Hello!!! Me (A seasoned biologist): I love you, but please, always 1 yard away from me please!!!

Thanks😄

Thanks!

The unnerving bit for me is I've lived in the home range for both Valley Fever and Rocky Mountain Spotted Fever. I haven't got either, thankfully, but still unnerving.

There are Guinea warms in South Nigeria too

Now I can't touch wild bats? Can't do anything any more My dad, we live in upstate SC, and he had rocky mountain spotted fever as a kid.

I like bats! They were the subject of my graduate studies. It's not good to overdue the warnings for any life forms. It causes unnecessary angst among the general public. But it is good to respect any life form - especially if you are not familiar with it - this include any life forms that may be from another heavenly body.

Basics are gold😊

John Green got me onto Crash Course. I kind of fell of when he did. I watched the Consumption doco though, great stuff.

As a funeral director in Utah I have taken care of a few CJD deaths. I think you are incorrect that it can only come from mad cow disease. Chronic Wasting disease in elk and deer is very high in Utah. And Scrapie in sheep is also a prion disease. It has been shown that these prions can be taken up by plants and when animals eat them then they can get them. If you eat elk or deer with this you can get this as well.

I love how there are so many species we are trying to save, and then there's these worms that are so horrible that we just said nope! These have to die! XD

Australia also has Ross River Fever and Barmah Forest Virus.

My aunt got rocky moutnain spotted fever from her time in the marines and bc of that no one knew what the hell was wrong with her until it was a bit too late to do much. She's still alive but... well, she can't do much on her own.

A family friend died of vCJD. It really was quite horrific, like the worst mix of dementia, parkinsons and ALS all in one rapidly progressing illness. I wouldn't wish it on anyone.

Funny. I thought it was Called Valley Fever for the San Joaquin Valley. I got it in the 60s & was told it was in the peat dirt.

🎯 Key Takeaways for quick navigation: 00:00 *🌍 Diseases can spread rapidly across continents due to globalization, leading to outbreaks and pandemics in a matter of weeks or months.* 00:57 *🐄 Variant Creutzfeldt-Jakob disease (vCJD), the human equivalent of mad cow disease, is caused by eating beef from cows with bovine spongiform encephalopathy. It's rare but fatal, with symptoms showing years after infection.* 03:17 *🕷️ Rocky Mountain Spotted Fever (RMSF), transmitted by ticks, primarily affects the southeastern United States. Early diagnosis is crucial as it can lead to severe complications, including death.* 04:44 *🌵 Valley Fever, caused by a fungus found in soil, predominantly affects the American Southwest. Symptoms vary, with some individuals remaining asymptomatic, but severe cases can lead to dissemination to other organs.* 06:11 *🦇 Australian bat lyssavirus (ABLV), similar to rabies, is transmitted through bat bites or scratches in Australia. It's highly fatal, and prevention involves avoiding contact with wild bats.* 08:02 *🦇 Nipah virus, spread by bats, mainly affects South Asia. It can transmit from person to person, with symptoms ranging from asymptomatic to severe encephalitis, leading to a high fatality rate.* 09:26 *🦇 Marburg virus, transmitted by bats, causes severe flu-like symptoms and hemorrhagic fever in humans, with fatality rates varying between strains. Outbreaks typically occur in Africa and have been contained with public health measures.* 10:24 *🐛 Guinea worm disease, caused by infected water fleas, results in painful blisters and long worms emerging from the skin. Efforts have almost eradicated the disease, mainly found in sub-Saharan Africa.* 12:42 *🌍 Geographically isolated diseases often require direct contact with the disease's primary host, limiting human-to-human transmission. Travelers should heed public health warnings and take precautions, such as vaccination and hygiene practices, to minimize risks.* Made with HARPA AI

watching this while staying home sick from work really has it's own kind of irony.

Kuru is another fascinating spongiform encephalopathy...caused by cannibalism. That one definitely isn't leaving it's area from what I understand. Man, is it freaky though.

CJD is spread through neuro surgery in humans as well. Prions will not die through conventional sterile processing methods. Many surgeons rather use disposable instruments instead of risking the prions surviving the sterilization process. The origin of CJD spreading in neuro surgery is a whole other story, but we do know why and how CJD started. Unless what i was taught in the surgical field is hush hush now since large corporations don't want that information spread around. I'm not sure why this channel went with "we don't know" when we most certainly do know. It was a result of pharmaceutical companies, whether it be growth hormones or some sort of antidepressant I can't remember, but it began spreading person to person because of pharmaceuticals. Despite digging I can't find it online, go figure. Would have to go through my extremely old class notes to find the lecture.

Here in Australia, most bats are also classified as flying-foxes or fruit-bats, although some of the less common smaller species are technically just bats which have little direct contact with humans! However a few years ago in the northern states there was an outbreak of Hendra-virus amongst a few people who worked with horses that had contracted the disease! So yes, stay away them!

that's crazy

I've known two people who have gotten Valley Fever. Both have gotten meningitis from it. That meningitis doesnt go away. Ever. Once you're diagnosed with VF meningitis, you have it for life and have to take antifungals forever to control it. Note that this is a rare, rare complication and both these cases I know were already immunocompromised when they were infected.