Scientist Radek Lučan on bats’ remarkable immunity ****************************************************************************************** * Scientist Radek Lučan on bats’ remarkable immunity and links to Covid-19 ****************************************************************************************** A number of deadly viruses are believed to have originated in bats, including Ebola and th SARS. The indications are that the novel coronavirus SARS-Cov-2 also made the jump from ba through an intermediary species. Why are so many pathogens linked to the flying mammal? Ra CU’s Department of Zoology [ URL "https://www.natur.cuni.cz/eng"] says the answer lies in robust immune system. In short, bats can weather viruses that in “a perfect world” would n to humans. Bats are fascinating creatures - why is it that so many viruses seem to come from them? Th read about Ebola, for example, was in Richard Preston's The Hot Zone quite a while ago, an were linked... Bats are ancient: there are fossils showing they were around more than 50 million years ag Homo habilis lived two-and-a-half million years ago. Many species of bats have simply been very long time and encountered viruses of all kinds throughout their evolution. Bats do no capability of powered flight. They have remarkable social organisation, longevity and ther they also developed very strong immune systems over time. While they may be hosts for a number of deadly diseases, we lack evidence of any direct tr humans. Historically most zoonotic viruses have come from domesticated animals and not wil Also, the number of zoonotic diseases that are transmissible from human to human are minim of viruses out there, but there are of course exceptions. Deadly viruses from Ebola to Marburg or the first SARS were found in bats; but in order to how pathogens jumped to humans (whether it was directly or through an intermediary animal) be able to locate Patient 0. That is practically impossible. For example, we have no idea in the transmission of the coronavirus SARS-Cov-2 that causes Covid-19. Experts warned for years that a deadly pandemic was coming and there were earlier threats: avian flu. Covid-19 is the one that went global, becoming an unprecedented health crisis… Human population density plays a central role: if a pathogen is especially virulent and hu transmission proves possible, it can move very quickly. When you combine this with how int globe is today through air travel and trade, a pathogen can pop up on the other side of th matter of hours or days. I am not sure how we can change that. As we press up more and more against nature, it seem likely that such situations will happen. If you take into account the diversity of wildlif the density of local populations in tropical areas, the chances of an outbreak are even gr difference is, in the past pathogens could not spread as quickly. Many of my colleagues lay the blame with humans for encroaching more and more on nature, b more people live in big cities than ever before. Half the people around the world live in less contact with nature than ever. Eighty percent of kids in the Czech Republic for examp recognise a blackbird. Even when I take my students at the university on fieldwork to stud a real eye-opener for some of them because it is the first time they have ever slept under of them have never been in the forest at night. If we have less and less contact with nature – what about other countries? I spent a lot of time in the Middle East and in North Africa and the contact between local animals was not as common as you might think. If we are talking about bats, they might fea shamanistic rituals. If we are talking about parts of Southeast Asia and some parts of Afr bush meat, consuming bats such as “flying foxes”, along with domestic animals like cats an of these animals are cooked or roasted and heat of course kills viruses. The danger is in preparation of the raw meat: that is the point where the virus can make the jump. It is hard to imagine how things might be different in the future. If your city is at the outbreak there is even less time to respond, even if you know how. Short of living in some sci-fi fantasy, it’s not clear how much can really be done. We’d h completely apart from nature and be living in some kind of sterile aquariums hooked up in VR existence, which is nonsense. We will have to get used to the fact that there will be e illnesses and we have to prepare for them as best we can. I strongly believe we have enoug and know-how to manage such threats successfully. To come back to the current outbreak, there has been a lot of speculation about where Covi including no shortage of conspiracy theories. I don’t think any serious scientists are entertaining the idea that it was bioengineered b is striking, at least for many of us who study bats, that the outbreak happened in the sam level-4 lab was studying bats for zoonotic illnesses including coronaviruses. The lab in W just around the corner from the wet market where China officially said it began. And of co almost immediately shut down as news of the outbreak got out. Only conspiracy theorists th is manmade but it is not hard to imagine it could have been the subject of study in the la got out. Given it is a novel virus and given it is often asymptomatic, a scientist could have been virus and accidently carried it out of the lab without knowing. He or she could even have the market and the sheer number of people there, in the subtropical humidity, would have e spread quickly. Do you think an international investigation will ever uncover the truth? One question is China’s regime: I don’t think it will be at all easy to get to bottom of w only information that gets out is what the regime allows. Methodologically, I don’t see an done either: it is simply extremely difficult to trace back what happened. Even in scenari followed all of the necessary protocol and we even if we had a lot of the missing informat still be hard to piece together the exact chain of events. In terms of future threats, what is something we can influence? The unregulated hunting of wild game and the eating of bushmeat remains the problem: the e restriction would to limit the consumption of bats and wild game. At the same time, plenty restrictions in place and locals do it anyway and not because their livelihood depends on be a question of tradition. I spent some time in the Philippines where hunting for bushmea every local has a firearm using CO2 cartridges. They hunt by flashlight and fire these gla creature that blinks in the dark. They could live without the bushmeat but for them the meat has a deeper significance. They having medicinal properties and – illegal or not – bushmeat is simply is part of their way that to change, there would have to be people monitoring the situation on the spot, which It comes down to education and upbringing and that is not something that can be done “over By comparison, in the Czech Republic, the hunting of traditional game like wild boar or de also regulated and meat has to be tested and meet veterinary standards for parasites and d pathogens. But there is no reason a novel virus couldn’t slip through undetected the same doesn’t have to be in some place far away in the tropics. When it comes to studying bats in the field in the Czech Republic, are any precautions req There are around 45 different species of bat in Europe and most of them are tiny: while we gloves and carry disinfectant, their bite wouldn’t even break your skin. We wear gloves es comes to the bigger species and bites are simply unpleasant. The threat of rabies exists b very rare – much less than 1 percent of the bat population have antibodies which still doe have rabies. We are vaccinated of course but here’s another interesting fact: unlike dogs, rabies present in their saliva so the threat of transmission is absolutely minimal. Throug never heard of a scientist dying from anything caught from a bat. You have done a lot of conservation work as well as popularisation. Do bats enjoy a better because of it? They do. The Czech bat conservation trust – which I was a secretary of for many years - do public education, such as International Bat Night, attracting around 10,000 visitors at ar the Czech Republic annually. We are involved in Czech schools with presentations and lectu perception has certainly changed. In the old days, if someone found a bat in their attic they would just bash it with a shov know better and they know whom to call. In all seriousness, people have learned what fasci bats are. The protection of bats is in our legislation so when you have the renovation of blocs underway and bats are found, bat houses are put up for their protection. Without que seen a lot of progress over the last 20 years. Historically, bats got a bad rap as well, didn’t they... In medieval Europe, or the Christian world, they were associated with night and areas unde brought to mind Hell; their wings were seen as demonic. In many cultures in the past, bats or disliked but one exception was Japan, where they were a good-luck symbol. Bats are rema are very beneficial in many ways. They play crucial roles in tropical and other ecosystems for pollinating all kinds of plants, including banana or durian. They keep insect populati mosquitos, in check. A single bat can eat one-third of its body weight in mosquitos in a s In 2007, a study in Science showed that in the US one single species, the Mexican Free-Tai America four billion USD per year in insecticides. They have a positive impact. While they certainly carry viruses, as I said, there is no record of any direct transmissi beings. If anyone was ever at threat it would have to have been Ozzy Osbourne [in the infa when he allegedly bit off a bat’s head. And he was okay and has been going strong ever sin otherwise? Ordinary people almost never come into contact with bats and even when they do, more likely to simply spot them flying overhead than to ever hold one in their hands. Radek K. Lučan, Ph.D. is an expert in vertebrate zoology, chiropterology and biogeography professional interests include the population ecology and conservation of bats in the West aegyptiacus) in the Mediterranean region and conservation ecology of grey long-eared bat i Červenohorské sedlo Mountain Pass in the Jeseníky Mountains.