Infections and the Brain

so this evening I'm going to be talking about infections and in the brain and the reason I'm talking about that is that they are widely feared rightly feared because when they cause problems they can cause very severe problems but also I'm glad to say in many cases in retreats as we saw go through the reason it is so important to consider infections in the brain is that the brain is of course our most important and undoubtedly our most complex organ everything you do your thoughts your actions your sensations your emotions all come from the brain

so anything which damages the brain can have long and very serious impacts on you for the rest of your life and the brain is therefore protected from infection by multiple layers some of them are layers of the immune system before you get near the brain but they're also some physical layers around the brain which are broadly termed them in in G's and these are important for three reasons the first one is they provide a physical barrier to many infections getting into the brain that get into the rest of the body but and there's a downside

to this they also provide a physical barrier to drugs used to treat infections getting into the brain as well so there is a there is a flip side to that and the third reason they're important is inflammation of this tissue the meninges is what's caught what causes meningitis which is one of the major brain infection types now the brain as you all know is highly specialized the only way it can do all the very many things it does absolutely in you at all times is to do parallel processing lots of different bits of the brain

are very highly specialized so some infections will in fact affect the whole brain other infections will affect very localized bits of the brain and may then cause a very specific part of damage leaving the rest of the brain untouched so the degree of specialization can lead to very different outcomes and I've Illustrated this here for example with the fact that you have one strip of the brain deals with your motor system actually commands your body how to move and next door to it a strip completely devoted to our sensation and even within that there will

be highly specialized areas which control things like the hands the mouth or the tongue now the brain is affected by very many inflections I'm not going to go through all of them very obviously but I'm gonna try and deliberately go through a wide sweep so you can see the direction of travel on infections of the brain we have at the moment and this talk is going to consider meningitis and careful itis parasitic infections are very sorts of the brain localized infections which can cause a rather different presentation and then the general infection effects of infections

on the brain particularly in older people because these are broadly the groups which tend to cause significant problems let's start off because historically and in many areas still it is the most important with meningitis and I think almost everybody in this audience will know the symptoms of meningitis because they are ones that people rightly fear and rightly are told about in education and by their doctors and by their parents headache obviously common neck stiffness where people really find it incredibly difficult to move their nitin neck a version to light photophobia is the term for it

and fever are the classic things which caught which point to meningitis people can have meningitis II don't have all of these but most people who have a severe case of better meningitis will have most or all of them and the diagnosis is still by a very old fashioned method really lumbar puncture and lumbar puncture is where you take a needle and you pass it through the bones between the bones in the back into the spinal cord area where the fluid that washes the brain is also in the spinal cord and there you can actually see

what is happening in that fluid in what's called the CSF I want to stress although I mainly be talking about how we've controlled disease that many cases of meningitis have a very good outlook so people who have a viral meningitis which I'll come on to almost invariably make a full recovery and people who have a bacterial meningitis provided it is identified early can usually be treated and have no or very limited long-term problems so these are either not always severe or treatable diseases nevertheless they are always potentially extremely dangerous and potentially can leave people even

if they survive with long-term neurological problems when you do a lumbar puncture the first thing you may see if you're doing it and you may see this in any relatives hopefully not any close relatives is actually the fluid that comes out which normally will look as clear as water can actually look like pus if you do that you do not even need to see what happens under the microscope that tells you this person has got meningitis more commonly however what people need to do is look under a microscope again old-fashioned medicine this has not been

done really differently to what would have been done 50 years ago and under a microscope in general with meningitis you either see these purple multi layer loculated cells these are called neutrophils and this tells you this person has got a bacterial meningitis or you see these single dot cells lymphocytes and these tell you that they've got viral meningitis or possibly TB meningitis or fungal meningitis so quickly looking down the microscope will usually tell you broadly what you're dealing with this is not something that's something you could teach at a bright twelve-year-old dude once you've actually

done the preparation and then sometimes you use relatively old-fashioned methods to actually make the diagnosis straight away by seeing the organism that's causing the problem and I've given an example here this is a fungal meningitis sowing called cryptococcal meningitis and what is they've done what people have done in this is they simply put in a drop of old-fashioned India ink and the ink causes the area to be brown and because there's a capsule around the the yeast cells that cause this that leads to a halo around it and you can very clearly see these organisms

so sometimes you can make a diagnosis as straight away just by looking down a microscope now there are three very common historically causes of bacterial meningitis and I think what I want to say straight off is we're making extremely good progress against all three of them let me start off with meningococcal meningococcal meningitis something which people are rightly very afraid of it's carried by around 10% of adults in their nose and throat so if you look around the population some of you will have this in the back of your throat this is a common bug

for a lot of people just to carry and for most people it causes no problems at any point in their life but it can cause a very aggressive meningitis it can also cause a form of septicemia which causes a very unpleasant rash this child's family wanted their child to be seen so people could understand this and what happens then is there can be a very rapid onset so a child can be playing perfectly happily in the morning and be intensive in intensive care by the afternoon this can happen extraordinarily quickly and untreated this has a

mortality of around 50% so this is a very serious infection indeed it is fortunately sensitive to antibiotics but that does depend of the on them being got into people at a very early stage so the first general public health point is if you see someone who might have an aggressive meningitis they need to see a doctor absolutely immediately now there are several different sorts that meningococcus ABC wxy are the rather unoriginal names for these which of these are the most important varies both by age different ones come at different ages and by geography so different

ones are more important in different countries and this has got big practical implications but for all of these now there are effective vaccinations available and we start off with the one that's most globally important and this is meningococcus a this causes massive epidemics or least historically until very recently caused massive epidemics in many places but particularly in the Sahel area of Africa and if you take for example the last really massive epidemic in 1996 there were over 250,000 cases occurred in this epidemic wave this is a very very serious epidemic by any standards because we

now have a good vaccine against meningococcal a which is now being widely deployed outbreaks have been virtually eliminated that doesn't mean the infection has gone away completely but these big outbreaks are no longer occurring and after this vaccine is introduced there was around a 70 percent decline in managing meningitis in this region that's in the last few years that's an astonishing public health achievement the still are some outbreaks in this area of many many Hawker C&W including one major outbreak that was imported following a pilgrim coming back from the Hajj so demonstrating the risk of

going to crowded areas but this is a problem which whilst not gone is a shadow of what it was just a decade ago looking at Europe the USA and obviously the UK a different form of Meninga caucus is the most important or two important ones had many the caucus B and C and more recently W and again the headline numbers are extremely encouraging we've had a reduction in invasive meningococcal disease from over 2,500 cases when we were at the turn of the century to around 755 last year and most of these are children under the

age of five there's a smaller peak in teenagers this has been injured this is largely been produced by a introduction of meningococcal C vaccine which was introduced in 2000 and it reduced meningococcal C by about 95 percent in children and then since 2015 so this is just three years ago the children in infants in England have been offered many a caucus B vaccines because most cases is I'll just show you are in children under the age of 1 so highly concentrated in this group and since 2015 also teenagers have been offered meningococcus ACW and why

because there is a risk of those infections in the teenage population and this is the age distribution this is the reason why these are the ages that have chosen these are all the cases of meningococcal and the black ones meningococcus type B and the blue ones are meningococcus Type C and what you can see in the UK is over time Meninga cross types Eve due to vaccination has essentially disappeared and I would expect the same thing largely to occur when the news to caucus type B over the next few years as a result of the

vaccine program that has just begun and then you have the acwy vaccine to deal with this peak in teenagers later on so Meninga caucus we are getting on top of extremely effectively with vaccination in children the other major meningococcal bacterial infection used to be when I was a medical student in a junior doctor something called him off less influenza this is not the same as influence of the virus this is a bacterial infection and it was a communist cause in children under the age of 4 one in 20 of them died and one in five

who survived were lest left with serious neurological disability again a very serious infection he black scene vaccine against this was introduced in the you Ireland in 1992 and and almost immediately reduce the incidence by more than 90% and this is a graph of what happened when the hip vaccine was introduced basically it fell off a cliff and then there was a catch-up vaccination campaign needed slightly later on so in 1991 there were around just over 700 cases of meningococcal infection last year there were only two so this disease is not completely gone but it has

been very largely reduced and it also reduces carriage which means that children even who are not vaccinated are protected by those around them and if you look globally following on from what happened in the US UK and northern Europe so if you look at 1996 only those countries actually had significant amounts of vaccination protection if you look in the last year for which we have data 2016 very many countries in Latin America Africa Europe and includes crease in the Asia now have protection with is highly effective vaccine so this infection is basically on its way

up due to vaccination if this sounds this whole talk sounds like him to the extraordinary power of vaccination to defeat dangerous diseases it is moving on to pneumococcal meningitis this is the third of the large of the big three bacterial meningitis and this occurs almost entirely in young children under the age of 2 and those over the age of 65 is carried in the throats of many adults and over half of preschool children so this is again a common bacteria lots of people carry it but it only causes severe disease which can include many core

causes meningitis but it also can cause pneumonia septicemia a variety of other things because a number of diseases but only causes this in a minor minority there's a very high mortality familial pneumococcal meningitis and around one in five survivors will go on to have significant neurological ability again this is a serious infection we now have routine immunization for the 13 most common strains in infants and we also have vaccines for the over 65s which are slightly different and what's happened as a result of that is this is every year over time and the solid lines

along the bottom are the strains that are presented by prevented by vaccination and what has happened over time and essentially these strains the most common strains and pneumococcus have largely disappeared as invasive disease there are still some strains and pneumococcus which are circulating which are not covered by the thirteen valent vaccine that we have and therefore there is still some disease that's circulating but that is the overall burden has really substantially reduced so again a remarkable impact from vaccination the Robin it's a number of very rare or fairly rare meningitis it ities and one of

them in particular deserves talking about this is this thing Group B streptococcus GBS this is the main cause of meningitis in newborns in the UK and indeed in most higher income countries the numbers are very small but each of the cases is clearly absolutely tragic and this does present a very significant public health conundrum because we know that twenty to thirty percent of pregnant women will carry this bacteria on them when they're pregnant and could potentially infect their children over ninety nine percent of children born to mothers who are infected will not go into con

to get meningococcus and the question therefore is should we screening all pregnant women and giving a third of women in pregnancy antibiotics with a number of significant downsides particularly antibiotic resistant infections or should we be accepting that this is this very small number is probably on balance actually less harmful than that approach and this is a very live debate in public health and in obstetrics at the moment the argument is really quite finely balanced what we really need for this is clearly a vaccine and I think a vaccine at this point I'm afraid is probably

more than five years away and then there are a number of really very rare infections Listeria infection now very rare usually much more common if you're pregnant and you eat these cheese's you'll be very pleased your baby may not be and you may get meningitis so avoid unpasteurized infection cheese's in pregnancy and there is a very rare Salmonella one which is largely caught from people's pet reptiles the last case I came across was from a pet water dragon they look very cute very occasionally they're dangerous including obviously to humans as well as to slugs TB

meningitis is the most serious form of tuberculosis and in wealthier countries this is now incredibly rare when the NHS was founded 70 years ago there were about 2,000 cases of TB meningitis a year and they were mainly imported they are mainly transmitted in the country and England and Wales are now around a hundred year that's a roughly two percent of TB overall children under four and hiv-positive adults and most risk in most settings in a high-income setting BCG vaccination provides around 75 protecting the percent protection against meningitis so it protects much less against lung disease

but it protects against meningitis but unfortunately is less effective in low-income countries and it is in low-income countries where the burden of TB is a most a risk and so there is still TB meningitis this is one of the ones where we have still got some way to go and it is concentrated in particular in areas where there is a large amount of HIV but the other big threat is drug-resistant multi drug-resistant TB is a spreading problem particularly in Eastern Europe and I mentioned HIV HIV makes multiple forms of meningitis a lot more common TB

pneumococcal certainly two of them but the third group that it makes much more common as a very unpleasant and infection cryptococcal meningitis which is a fungal meningitis and the reason that this used to be massively feared is people would get this they would get incredibly severe headaches would survive for roughly three months feeling incredibly unwell up to three months and then they would die but the last few months in their life were very unpleasant that was in before we had effective anti HIV drugs now we've got those this problem has largely disappeared if you've treat

people with anti HIV drugs and you treat the in the the meningitis this problem will go away and finally on the main section on meningitis viral meningitis as I said at the beginning this is generally mild it usually lasts less than 14 days so when you say someone who got meningitis they look at you as if they're about to die it is viral meningitis the risk of that are very low indeed and generally there are no neurological after-effects not absolutely always there's no treatment for these viruses are not treatable by drugs the rates have gone

down quite a bit because it used to be that around one in four of these cases was due to mumps and now with MMR vaccination that has largely disappeared and there were also some cases due to measles those also have gone down with NMR but several other viruses can cause it and then mainly the gut viruses in particular of childhood other things can as well so that is meningitis broadly an incredibly encouraging picture less encouraging is in cattle itís any careful itis is not information of the surroundings of the brain this is inflammation of the

brain itself this white our area out here and several several common infections can rarely cause in cattle itis but when they do it's usually very serious they're around four to six thousand cases a year in the UK that would be fairly typical for high-income countries and where we know what causes it the common causes are herpes simplex that's the cold sore virus that most people have at some point in their lives which can for reasons are not really clear sometimes invade the brain chickenpox virus and measles and rubella he German measles in people who are

not vaccinated and then a variety of much less common causes at least in this country but this is a serious condition which can leave people with very significant long-term disability start off with the most common of them herpes simplex encephalitis for which we do not currently have a vaccine of those identified it's around 20% of the cases in the UK but actually a lot of in careful artists we never know what causes it to be clear this is actually very rare and so the numbers are around 0.3 per 100,000 of the population a year this

is not something you or your friends are likely to get but clearly there is always a risk typically it affects that this bit of the brain here which is an area involved in the processing in particular of speech and sensation and orientation and what you tend to get is flu-like symptoms and then very different for meningitis people think they're the same thing they're very different people get drowsiness and unconsciousness they may or may not get a headache confusion difficulty in communicating and then go on to have fitting so very different if they have epilepsy of

different sorts since there's no vaccine we have to really rely on treatment unfortunately for this form of encephalitis for those who are treated early there is an effect fairly effective drug called acyclovir if you started in the first 48 hours then it reduces mortality from around 70% to around to less than 20% so this can be very effective but several of those people will be left with significant long-term neurological damage so this is not something which is trivial even with treatment much more depressingly is we still have cases of measles and careful itis and the

reason I say depressingly is this is almost entirely preventable and I will just give you starkly the numbers in a high-income setting in a low-income setting up to 10% of children with measles will die from it one in three children one in three to having a thousand children will developing careful artists during their measles episode and ten to 15% of those will die and a further 25% of those will have a long-term neurological damage which affects them for the rest of their lives one in a thousand children with measles will develop a post infectious mick

hepatitis so they get through the measles and then they getting careful itis and one in twenty five thousand children will develop subacute sclerosing panic hepatitis A severe and careful itis they get many years sometimes many years later this is a non-trivial infection compare that to less than two in a million children who will developing careful itis after vaccination and I'll just leave up this is a letter that Roald Dahl wrote to all parents after the death of one of his children from measles and keval itis and I'm not going to read it out I think

people can read it on the screen well she was alive he dedicated germs J James and the Giant Peach to him to her after she was dead she dedicated the Big Friendly Giant to her to two books most children know very well I think that letter is worth selling to people who like to claim that we should not be giving MMR vaccinations to children which I consider is one of the stupidest things currently said in the popular press so moving on from hepatitis which in a sense is an accidental if it's you where the infection

infects but probably not as part of its deliberate strategy in evolutionary terms to one where it definitely does rabies rabies as an absolutely horrible disease having seen many infectious diseases I can say without any hesitation that rabies is the one that I would least like to die from around 99% of human cases come from dog bites globally and it is still really quite common so just under sixty thousand cases a year according to the World Health Organization where it's controlled in dogs there is a little bit of whirring bats but this is much smaller but

that is a bit of an issue in the Americas but that's only really noticeable once it's controlled in dog dog populations if you get rabies with symptoms you'll die within 10 days of those symptoms but you will feel appalling ly terrified for those 10 days it is a really awful way to go and you see people in utter terror so therefore the final days of their lives what the virus does because it of course has only got 10 days to pass itself on or a very short period a number of days and this is true

in animals as well so what it does is it firstly prevents animals including humans from from swallowing properly so they're producing huge amounts of saliva which is where the viruses is and then it changes the brain to make them highly aggressive so in the case of dogs they're actually biting anything which they can bite so the brain has manipulative brain is manipulated by the infection to get itself passed on this is part of its actual process for transmission again rabies can be prevented it's entirely by vaccination if you vaccinate all domestic dogs that reduces the

rates incredibly quickly you can then do base baiting of wild things for example you could put bait you can put a vaccine on to the heads of chickens that are dead obviously and leave them out and while foxes for example will take those and you can also if people have got a bite from an animal that might have rabies you can vaccinate them after the bites but before they get symptoms and if you do it in the first few days there is virtually a hundred percent certainty you can prevent that infection so the vaccine is

both preventative of getting the infection and also can prevent people who have been infected from developing symptoms and rabies has now dropped really quite substantially except in the countries in red that you say here but this is something which if you control rabies in dogs rabies will go away so this is again a vaccine preventable disease and here are just some examples what happens as if you increase the vaccination in dogs rabies and dogs Goes Down and therefore rabies in humans goes down it follows as night follows day so vaccinating dogs against rabies a very

good thing to do some of the magnetic apparatus you get in parts of the world is transmitted by particular insects and I'm just going to give a few examples there are actually quite a many quite many the most common of those the most important of them is a careful itis you get in Asia called Japanese being kept alight is it can cause no symptoms but it can be very severe up to some just under seventy thousand cases again according to the latest estimates it's the commonest cause of in careful itis in Asia so this is

actually quite a common infection and is passed on by mosquitoes the reservoirs in paints so it part that this cycle is pagan wild fowl to humans but there are again fortunately highly effective vaccines against this common infection here for example is what happened in Taiwan I put an arrow where the vaccine was introduced this in careful itís basically almost entirely goes away and then there are other mosquito rarer mosquito in careful it --'tis I'm not going to go through them in detail including some like West Nile virus which we have in parts of Europe not

are currently in the UK another insect that can pass these honor takes and there is an important tick-borne encephalitis which again is particularly important in Eastern Europe and large parts of Asia just like with Japanese being careful itis we have a highly effective vaccine if you're vaccinated before you go into the area at risk then the inka Politis is not going to happen and other very specialized tick-borne in carefully to these can happen elsewhere i've just given an example from the USA a tick-borne disease which is a bacterial disease is a rather strange what's called

a spirochete bacterial disease which a lot of people know about including a lot of true information a lot of misinformation is lyme disease this is a tick-borne infection that can have any number of info of effects but it can certainly cause inflammation of the brain it's a bacteria it's rare in most of the UK but much more common in quite large parts of Europe so for example in the UK largely around for example the new forest area but in the black forest area many parts of Scandinavia the rates of infection are considerably higher and very

significant rates in parts of the eastern seaboard of the USA a line Connecticut is where this was first destroyed it can be genuinely difficult to diagnose but and this is the bit where I think the misinformation comes in antibiotics are highly effective at curing this infection at all stages in the great majority of people that would not want to claim all but the great majority of people and control studies suggest that Lyme if you get it neuro line actually has a very good outcome so this is a very recent study that was done in a

Danish population comparing 2000 people with Lyme disease neuro Lyme disease with people with the teeth to 20,000 people in the general general population what it demonstrated was the outcomes after they'd been treated were virtually the same whether you're talking about hospitalization employment income disability or schooling in fact the only area where there was a significant differences in marriage where people who had near a line got married more often but otherwise they were basically identical another spirochete disease now much much rarer but it used to be a really serious problem including here in London was neurological

syphilis also known as general paralysis or the rather grandly named general paralysis of the insane if we'd gone back a hundred years ago it was extremely common so somewhere between 12 and 25 percent of all diagnosis in the mental institutions of the day were neurosyphilis this was very very common indeed and there was a Royal Commission at that stage almost exactly hundred years ago that estimated and I think probably accurately that around 10 percent of the adult male population in London at that stage had syphilis so this was a common infection it happens usually cause

normally somewhere between ten and thirty years after infection so this doesn't happen initially it happens later on and what it leads to is people having very grandiose ideas they think they're going to rule the world they think they're going to win every lottery they have huge ideas personality change going on to dementia and then eventually paralysis many famous people are thought to have had it if you read any history book you'll find lots of people who have actually been described as having it we certainly know that some people historically important had it for example Al

Capone had a proven case of neurosyphilis at the stage when mr. Capone was doing his his evil worst the best treatment for syphilis was actually to infect people with malaria and the reason for that was malaria caused the fever to go up extremely high and the fever killed the parasite this will kill the bacteria of the neurosyphilis so using one infection to cure Corky's or to cure another infection but the thing which transformed the outlook for neurosyphilis was en advent of penicillin penicillin is still highly effective in syphilis and actually what in fact happens is

most people who have early syphilis because if a nurse still exists much lower levels get treated without even knowing it when they're given antibiotics for their GP for let's say a pneumonia or something else so antibiotics between the first infection and the neurosyphilis will lead to people not going on to get this very serious late effect so again it's going away but in this case it's going away because of treatment finally before I move off many going careful itís something which is very rare but every time it happens it gets onto the front page of

the newspapers because it has such a dramatic presentation and this is amebic meningoencephalitis caused by this oak Naegleria fowleri at canary this rarely these are very rare occasions so 34 cases in the USA in ten years this is not a common organism not occurring here but it enters the nose when people swim in warm untreated freshwater so this is not from zooming pause this is swimming in warm lakes and ponds but when it does happen it's got an almost hundred percent mortality and it does literally heat the brain on its way in this is something

which obviously is pretty unpleasant to have but much more important parasites affect the brain and I'll I'm going to highlight three in particular and then a few because they're related to animals that we are very live very close to the fur the most important of them that affects the brain is malaria malaria still causes about over 200 million cases a year and causes over 400,000 deaths a year and malaria cerebral malaria is which is the formula that affects the brain which leads to unconsciousness fitting and eventually in many cases to death is one of the

major causes of people dying of malaria and the malaria parasites don't actually get into the brain but they get in very high numbers into the blood vessels in the brain the mechanism they actually kill people is not entirely clear but they certainly are there in very very high concentrations most people who died of cerebral malaria are children and poor and live in Africa birds every couple of years that will be deaths from cerebral malaria here in the UK from people who caught it mainly in Africa and imported to the UK it's not transmissible to other

people but it's very potentially dangerous but important positive but since 2000 so in the last 18 years malaria mortality rates have fallen by 62 percent overall and 69 percent in children under under five another area of massive public health success and here is not a vaccine that has helped us but old fashioned very old fashioned medicine bed nets treated with insecticides to stop mosquitoes biting and to drugs artemisia annua s-- wormwood which has been around in chinese traditional medicine for a thousand years at least and Quinny n-- imported from latin america over three hundred years

ago by the Jesuits and these the combination of these old-fashioned techniques has led to this dramatic decline in this major infection which affects the brain and these declines have occurred in every region in the world Europe where malaria is a threat practical purposes gone South Asia Africa and Latin America an astonishing positive story another insect transmitted brain infection again a very unpleasant one African sleeping sickness was a very major cause of mortality and it's passed on by this biting fly a flight the bite see you know about it this is this one and these parasites

get into the brain and there they gradually cause people's personality to change and they become demented and eventually they die and the reason it's called sleeping sickness is their sleep pattern inverts they sleep during the day and are active during the night like teenagers but rather more seriously just like malaria there has been a substantial reduction in the number of cases due to again old-fashioned finding people and treating them the drugs used to be incredibly toxic they still are pretty toxic but until 10 years 10 to 15 years ago the drug for treating sleeping sickness

killed five percent of people who gave it just the drug it was an arsenic based drug we've now got much safer drugs Diagnostics are slightly improved but the other thing which has helped us is that fortunately sexy flies are unbelievably stupid and they think that's a cow this thing on the right and if you paint this blue cannabis cow with an insecticide mosquito did if the taxi flies land on their hoping to get a good blood meal and that is the last thought they have putting these two together has led to a situation so if

you historically there were devastating epidemics of this infection in 1995 the whio estimated there were over 300,000 cases that's not that long ago by 2009 so that's just under 10 years ago night under 10,000 cases and the last year which we have data 17 under 2000 cases this parasites not completely on gone but it's clearly at this time at least at this time on its way out due to these old-fashioned stop kill the insects treat the people diseases much littler than less commonly kills people but is also very important is this infection called cysticercosis cysticercosis

is a parasitic disease of the brain and these are the cysts from which the thing gets its name it's actually a disease of pig tapeworms and the pig tapeworm is something which is passed on from human to pig and what happens is the humans get the tapeworm they then pass eggs in their stool the pigs who are other undiscriminating eaters eat the human feces and they then get infected and that goes into their muscles with cysts and then humans eat the uncooked pork and that gives them the tapeworm that's the normal cycle but just but

occasionally humans eat the feces of other humans you've got infection don't think about it too much before supper and they go on to get the cysts form which is actually meant to be in the pigs and if those cysts which cause problems it's a widespread problem it's probably the commonest cause of epilepsy adult onset epilepsy in the world so this is not a trivial problem this is a map of where it is most common and in contrast to some of the other things we've talked about the way of dealing with it has to be a

multi-pronged approach improving sanitation so people get rid of their own feces they don't it doesn't end up in the bellies of pigs or indeed their neighbors and the more husbandry keeping the pigs away from humans inspecting meat and if you can't inspect it cook it or freeze it both of those will kill it kill them and then finding humans with a tapeworm and treating them treat the pigs and increasingly we're going to rely I think in my view on vaccinating the pigs as well so this is an area where Pig vaccine will protect humans against

a serious human disease so talked about pigs maybe move on to another animal much beloved of particular Welsh and Scots sheep there is again at this case a sheep dog cycle and again humans in this case get infected accidentally so the parasite thinks that we're a sheep and what you then get is very large cysts some of which can go into the brain I'll talk about this more when I talk about the liver because it goes into other places as well so this is a situation where stopping dogs eating recently deceased sheep is a key

part of the control measure and finally as we know for those of you who are dog lovers I don't want to discriminate against you so a cat parasite toxoplasmosis this is another of those parasites than manipulates humor at our animal behavior so this is a cat mouse cycle cat is infected cat infects the the mice or the rats and the rats get it into their brains and they get it from that rats get it from cat feces the interesting thing about this from a biological point of view and rather depressing if you're a cat or

a rat so rat or a mouse is that if this parasite gets into the brains of the rats and the mice they start behaving incredibly recklessly they stop noticing the cat urine is around they start running into the middle of rooms and of course therefore they're more likely to be caught so this parasite is very clear data from this from multiple sites this parasite manipulates the behavior of the rats and the kappa and the mice to make them more likely to be getting into the brain changes the behavior of the animals humans are widely infected

so somewhere between 25 and 35 35 percent of the UK population probably has these parasites in their brain just think about that when you look around your neighbors probably it does little harm but there is eight there is a genuine debate about whether this infection which is caught mainly from cat feces actually does make bait humans behave a bit more recklessly as well and those who think that people who are cat lovers or strange people may have their prejudices here reinforced where it does cause very bad problems and there's no doubt about this is in

people who got HIV disease and they can have very serious problems of which are the most important is fitting so the way to treat this you can treat the the parasite but the key thing is to treat the HIV if you treat the HIV this goes back to being a relatively small problem so a cat a dog a sheep and a pee finally those are things where there's a cycle here's a situation where humans deliberately eat things that I'm not going to go into these in any great detail but just to say to you if

you like exotic foods great be aware that most exotic foods can pass on some parasites so there are forms of parasites which in particular there are some worms there are three worms in particular which you can catch from eating undercooked exotic foods frogs snakes and John's land snails are three classic examples swamp eels are a variety of others I do not wish to be a killjoy and tell you not to eat snake just don't eat it rare if you cook it the problem goes away so those do the parasites I want to talk about just

a few things I wanted to add on at the end a very rare problem which is not a meningitis but is a bacterial problem is abscesses as the brain and abscesses in the brain come on from either local infections often tooth infections or sinus infections much less common these days because of good dentistry and antibiotics but cases do occur they can also occur in no supressed of course people who got HIV in particular many people whose hearts have got structural abnormalities that infections can get onto them or can pass from left to right in a

way that you wouldn't normally expect and right-to-left as well some situations these behave actually very much like a brain tumor and when people first present doctors often think they are a brain tumor because what people have is headache locally which have worse normally lying down local effects where the area of the brain that's affected starts to stop that stopped working so for example of the speech area that's affected speech becomes reduced and then they start to fit this is a kind of classic presentation you get with a tumor they look like this on the scan

we neither do the scan and a combination of antibiotics and neurosurgery which is not anywhere near as delicate as many people imagine basically as taking a drill and putting the drill into the hole in the it where the bacteria and sucking out the abscess as you would any other abscess if you combine surgery in some cases and antibiotics most of these can be treated but they can leave significant neurological problems I would encourage you if you've got a bad abscess of your tooth to go and see your dentist finally two things where I think well

one thing where I think we're going the wrong direction I've talked so far about infections of the brain those are things which get into the surroundings of the brain like meningitis into the structure of the brain like careful itis and the parasitic infections I've talked about more recently but actually statistically the most common way in which brain function is affected by infection these days is something called delirium and delirium is something which occurs can occur in any age and some infections are particularly prone to causing it so they are typhoid for example classically does this

but the big risk for this is in people as they grow older and in older people particularly over the age of 85 but it basically increases gradually over time if you get what would otherwise be a trivial infection it might be a yearly factor tract infection it might be pneumonia this can lead to the brain simply not functioning properly we don't really understand the mechanism but it is very very common to intend hospital patients may have delirium over time this is not a trivial issue and for those who've seen it and many of you may

have seen it in parents grandparents partners at various points it is extraordinary frightening people have a personality change that's usually very short-lived with confusion drowsiness they may be aggressive they may become very different from their usual selves and it's a it's not an infection of the brain and usually if infection is what's triggered it other things can trigger in delirium but when infection triggers it usually it can be treated with antibiotics and this is just only going to go one way because this is a situation where older brains are affected by any infection because we

are going to have a significant increase in people who are over the age of 80 or in these maps here over the age of 85 over the next period the number of people who have this and less we find a way of treating this is steadily going to go up that is just a demographic fact so if you compare where we are now around to 3200 people over the age of 80 by 2048 most of the planners audience will hopefully be alive then there will be over 7,000 so this is going to increase and I

think it is not just going to increase everywhere here in London because people come in when they're young and leave usually in their middle years after their second child London will not have this as a major increasing problem but other areas of the country we're getting a lot older a lot faster will so if you're in North Norfolk if you're in the West Country there will be a lot of people in hospital with delirium and we need to think about that now and start planning for it and finally the other age of the age spectrum

this is a glass either half-full or half-empty infections are still one of the leading causes of acquired brain injury in children after childbirth others are trauma stroke lack of oxygen tumors and drugs and toxins in now the children in the UK and this will be much higher in many developing countries meningitis occur still accounts for around 13% of children who will need serious neuro rehabilitation and in hepatitis around 5% so glass-half-empty this is still a serious problem although the number of cases of meningitis is going to go down now we're getting proper vaccination and ringa

caucus but glass-half-full the numbers are now relatively small and falling so roughly a hundred children a year a tragedy for each of the families involved but the numbers are in absolute terms relatively small so my summary would be that people are right to fear brain infections like meningitis and encephalitis they are very dangerous they kill large numbers of people who get them and they can leave many people with significant neurological disability but if you look I've gone through here meningococcal meningitis [ __ ] meningitis pneumococcal meningitis HIV associated meningitis measles and careful itis jack being

careful I t's rabies malaria sleeping sickness and many parasites these are all going down in some cases at remarkable rates the outlook for brain infections is extremely in live year bright with a few exceptions which I've highlighted and for those who are part of the anti-vaccine movement if any of them are still watching can I just point out that all the ones that are asterisk the reason for this is we have effective vaccines so very good outlook very happy to take questions thank you very much you