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Describes how infectious diseases dominated mortality in the 19th century and how sanitation, hygiene, vaccines, and antibiotics dramatically reduced deaths in high-income countries.
Speaker A
Emerging infectious diseases Part 2 When Andrew Parker was born in 1895, the world was very different.
Most of the people were killed by infectious diseases, usually at young age.Child mortality was high.Family had more kids to start with.But like two out of five were killed early by infectious diseases.During the 19th century, 60% of the death was from infectious diseases.
But in general we are doing better since then.To today, the death from infectious diseases in high income countries is around 6%.We are doing much, much better as compared to 150 years ago.And that's made us in the 60s to deliver quite optimistic message to the public.
Speaker B
Never before in history have doctors been able to do so much to preserve your health as they can today and almost everywhere in medicine, the parade of advances that will benefit countless millions has just begun.
Speaker A
So the reason for such an optimistic message is, is based on reduced death from infectious diseases, which led to increase in the population on earth.
So what make us to be so successful with the fight on infectious diseases?
Well, the first time that we started to see some improvement was when doctors start to use better sanitation in the hospital.During surgical operations delivering babies, well, doctors started to wash their hands, as simple as that.And they realized that the number of infections in the hospital is going down.
And water sanitation, when we started to separate between the sewage water and the drinking water, as simple as that.
So we are talking about time.That basic idea about the connection between infectious agent and diseases was not clear at all.But it was clear that if you separating between certain things, for example, washing hands and separating between the sewage water and the drinking water, you can reduce illness from infectious diseases.That was the first time that we were able to see some improvement.
Vaccines, well, vaccines were developed initially quite slowly.The smallpox vaccine was developed towards the 19th century.
And later on we had other vaccines like vaccines against the rabies virus.And then a lot of other vaccines were developed during the 20th century.
And vaccines are the best way to prevent infectious diseases.
Here it's not about cure.I mean, people are not getting the disease to start with.
Vaccines, which in general, it's a very simple procedure, was able to save lives of billions of people.
And today we can see that every time that we had a new vaccine against a certain disease, the number of cases of this disease was going down quite dramatically.
At the middle of the 20th century, we were able to develop antibiotics to deal with bacterial infections.And that's another reason that we were able to do much better here against bacteria.Vaccines mainly are against viruses, although there are vaccines against bacteria as well.Better Sanitation all together were able to bring us to the level that infectious diseases are down quite dramatically.
So we were quite successful with dealing with infectious diseases, at least in the developed world.
Explains how success against microbes led policymakers to reduce research funding and assume the battle was over. The speaker then introduces the growing threat of drug-resistant bacteria, especially tuberculosis and MRSA.
Speaker A
However, our success became our worst enemy in controlling infectious diseases.Later on, towards the mid 20th century, most scientists and policymakers were shifting their attention away from infectious diseases, as many assume that the war against infectious diseases is over.
If you have a bacterial infection, there are many antibiotics that can be used.If you want to prevent viral infection, get the vaccine.
So the idea is that if you have a new disease, viral disease, we can make vaccines, a new vaccine against the pathogen, no issue.
And it brought us to the level that the Surgeon General of the United States told the Congress in 1969, it's the time to close the book on infectious diseases.They were dealing about the funds that should be used in research and to what fields.And that was the time that the amount of grants, funds to the research against infectious diseases went down dramatically.Who need this?Those labs that were dealing with infectious diseases.
Many of them decided to move to other topics, like cancer research, that the funding actually moved to this region, much more than what we had before.
So that was the time that we started to see that the research on infectious diseases and the new vaccines, new antibiotics that are being made, is going down quite dramatically.
So the statement that the Surgeon general did in 1969 was damaging.And today we understand that we were quite arrogant to think that the war with microbes is over.
Microbes are here for billions of years before us, and they will probably be around after us.
So are we away from infectious diseases?Is the war over?Well, not yet and probably never.
Speaker C
Today, we can prevent and treat diseases more successfully than at any other time in human history.We still, however, have much to learn about the relationship between microorganisms and human.
Tragically, infectious diseases still devastate human populations worldwide, most often in places where sanitary public health standards are not or cannot be practiced and appropriate medical care is not available.
And there has been an explosion in the number of bacteria resistant to antibiotics, and an alarming but inevitable emergence of new life threatening microorganisms.
Speaker A
So infectious diseases as a group will not disappear.
First, what we have on a regular basis is drug resistant strains of bacteria that are not sensitive any longer to most of the antibiotics that we have against them.
Tuberculosis, which is a disease that we were able to develop an antibiotic treatment in order to cure people from these bacteria.However, today we can see that like 40% of cases of tuberculosis are from a pathogen which is drug Resistant to at least one antibiotics.
So among the five antibiotics that we were using against tuberculosis, we are losing one antibiotic after the other.So today tuberculosis is coming back in some cases as a drug resistant pathogen.No treatment is available for this type of a pathogen.In some cases or the existing treatment are becoming more limited.
Mrsa, it's for meticillin resistance.Staph aureus, which is a bacteria that is resistant to certain drugs like methicillin.
Now there are other type of drug resistant strains from staph oils, vancomycin resistant staph oils.In many cases, when we are getting the infection with the Staph aureus, the treatment which is normally available against this pathogen is not working.Every year we can see more drug resistant strains of bacterial cells.And the list is becoming quite alarming because we are getting to the level that the days that antibiotics were able to solve problems with bacterial infections are likely to be over if we will not do something dramatic to stop this direction.
Covers newly recognized pathogens such as HIV, SARS, MERS, COVID-19, and Ebola, showing how aggressive or novel viruses can emerge and spread in human populations.
Speaker A
So one reason for emerging infectious diseases is drug resistant strains of bacteria.New disease causing agents.Well, from time to time we can see new viruses that are infecting us.We never knew about them, we never had them on our list.One good example is hiv.
We had no clue about hiv, the cause of aids.Acquire immunodeficiency syndrome.We had no idea about this virus at all.Before the 80s, a virus start to infect people in the United States.And that was the first time that we realized, well, we have a virus here that can kill millions every year.
And indeed that's a virus that changed the medical history on our planet.And coronavirus says The SARS of 2003 was absolutely a new pathogen, Quite significant pathogen at that time.
And later on in 2012 realized that another coronavirus from camels can infect people and kill like 35% of the infected people.
That's again quite significant coronavirus infection, which is a significant public health issue.Luckily, not many people are infected with MERS.Again, SARS and MERS are aggressive viruses.SARS scales like 10% of the infected people.MERV scales like 35% of the infected people.
Both of them are quite significant.And that's the reason that because of their aggressiveness they cannot spread very quickly.MERS is still around infecting sporadically people, usually directly from camers.And SARS is gone.It was out of the way like half a year after we start to see infections with this virus.
COVID19 well, that's another coronavirus which is significantly less aggressive from the adult too.And this is a virus which is infecting a lot of people.
It can infect people simply because the low aggressiveness of this virus.1% of the infected people confirmed cases are killed from this virus.So it's something at the level of flu when it comes to the case fatality ratio, more or less.And this virus that changed the world, as you know, in a way that no other virus did, is likely to stay.Why?
Because it's not an aggressive virus.It seems like that the virus can gain some mutation.The virus can be changed from time to time.So there is a chance that it's going to stay around for longer period of time.
Ebola virus, again, aggressive virus that came to our life during the 70s.We didn't know anything about Ebola virus before the 70s.We never heard about a disease that can be caused by this virus.So on the record, it seems like it is a new virus that made the jump to people sometimes at the second half of the 20th century.We can hear about this virus from time to time.
A virus that infect people in Africa in most of the cases, although you can hear cases in some other places in a more sporadic way, like what we had in 2014.
Discusses outbreaks that occur when diseases move into new regions through animals, trade, and smuggling, using West Nile virus and monkeypox as key examples.
Speaker A
What about outbreaks of existing diseases?
Well, I'm talking here about outbreaks of existing diseases that exist in one place and at certain point you find them in a new location.
And maybe the name of the West Nile virus is going to help us to illustrate this West Nile virus.Well, a virus that was infecting people for quite a while in the Middle east and in some part of Africa.That's where you can find this virus in most of the cases, but not in any other place.
And in 1999, we found this virus in North America.
The virus made the jump from the Middle east or from Africa to North America.
The way that it was done, it's not very clear.One direction is indicating the tire industry and there is this.At certain point, the tire industry in North America decided that they want to recycle the old tires all over the world in the United States and to make new tires from the old tires.So they bought tires from Africa and from all over the place.And you know, tires, if they are standing in a rainy day outside, they're going to be filled with water.
And it's very, very difficult to take the water out of the tire.
So mosquitoes, which are carrier of the West Nile virus can live there.They can move weather tires on those large cargo ships to the North America while they are infected with The West Nile virus.So the virus was moved to the United States.And since we have the same type of mosquitoes here as well, we were able to make this virus to infect birds and to stay around.West Nile virus is part of our environment right now.
Pandemic influenza.Influenza is infecting us every year, but from time to time we have a virus which is more aggressive.In 2009, we had the pandemic.Influenza was not kill so many people, but it was a new virus that start to infect people throughout the world.Luckily, we had the vaccine available quickly enough.
And this pandemic influenza of 2009 was not able to cause a very severe disease.
Monkeypox.Monkeypox is a cousin of smallpox.Smallpox, as we mentioned earlier, is quite a significant pathogen, killing a lot of people when it was around.
Smallpox is the virus.The only virus that we were able to eradicate means the virus is gone.
How we did this by, by vaccination, we were able to vaccinate most of the people on this planet against the virus.And since the smallpox is infecting only people, the virus have nowhere to go.So it's gone.Nobody's infected with smallpox any longer.Monkeypox is a cousin of smallpox.It was not eradicated.It is virus which is infect monkeys, but not only monkeys, it can infect people like this girl infected with monkeypox and a lot of animals, including rats and other rodents.
So we have a virus that can infect people.
It is not a smallpox, but a similar virus.The symptoms are quite similar to what we have in smallpox.Although the lethality that we have for monkeypox is low as compared to smallpox, the lethality from Monkeypox is approximately 10%.And indeed, we can see people in Africa that were able to to recover from this virus and are immunized for life against monkeypox and also against all the other pox viruses, because 90% of the infected people are going to survive the infection.
So the monkeypox can infect many rodents, including the giant Gambian rat and the prairie dog.
So giant Gambian rat, and as you can see, it's a giant rat is used by some people as a pet.And prairie dog, which you can see, it's not a dog, it's a rodent.It's a pet that some people really like.The giant Gambian rat is coming from Africa.It is illegal to bring this animal to the United States.
So people smuggle the giant Gambian rat from Africa.Of course, in this case, the smuggled animal is not Checked for pathogens such as the monkeypox.In 2003, in Chicago, Illinois, like 71 people came to the hospital with something that looked like smallpox.Well, I mean, you can imagine how everybody was worried that smallpox is back.But after doing some more analysis on the virus infecting those people, they realized that it's not smallpox, but is the monkeypox.
So how we have monkeypox in the United States?
So what we realized is that the giant Gambian rat that was smuggled to the United States was brought to a pet store.And over there, the giant Gambian rat had a fight with the prairie dogs, infecting the prairie dogs.Someone in Chicago, Illinois got the prairie dog from this store and got infected.And probably we had some infections, not just from the prairie dogs, but even human to human.Well, eventually everybody was recovered.
But we realized that a pathogen that is not supposed to be in certain parts of the world can very easily make them move from one place to another.All you need is a cargo ship where someone is keeping the animal as a pet or simply in order to smuggle them to the United States for money.
Shows how human behavior helps pathogens evolve and spread, including bushmeat hunting, pet trade, farm amplification, and cross-species transmission in shared environments.
Speaker A
So when we think about emerging infectious diseases, in most of the cases, it's not just about Mother Nature.
We are helping those emerging infectious diseases to be evolved.Few examples for this.The aids, a disease caused by hiv.The HIV was evolved from another similar virus that is infecting chimpanzee.SIV is the origin of hiv.
People got infected with HIV probably more than once because chimpanzees are used in some parts of the world as a bush meat.Means people are going to the forest in order to hunt for chimpanzees for their meat.So they are likely to get an infection with viruses that chimpanzees are carrier of.So the SAV was evolved to HIV sometimes during the beginning of the 20th century.And we never heard about this virus at that time.
But during the 80s, we realized that the virus is moving very quickly in the homosexual community of the United States, California, New York, from the gay population of the United States, the virus move to people which are injecting drugs, injection of drugs.It's a very effective way to transmit viruses that can be found in the blood.And if someone which is infected with HIV is contributing blood to the blood bank, you are going to have quite a lot of people to be exposed to this virus.So Mother Nature is doing just the beginning of the process.We were helping HIV to be evolved in a quite significant way.
So we will talk about the way that source is Transmitted from bats to human being.And the intermediate animal was palm civet that is used as a meat sauce in some restaurants.The chef got infected and the chain of infection eventually brought the virus to hotels.When the virus start to spread among a lot of people, and then when people came to the hospital to be treated, they were infecting many people there as well.Patient, staff, West Nile Virus.
Normally you can find this virus in wild birds, and they can transmit this virus to each other by a mosquito that is biting one bird and then bring the virus to another.But we were helping the transmission of this virus to the United States, probably by tires from Africa, as I described earlier.
And influenza, the influenza, it's a virus of ducks.You find all type of influenza virus in ducks and they are flying from one place to another.And from time to time they are stopping by the chicken farms for a nice dinner.There is a lot of food over there for them, and that's the time that they can infect chickens in those farms.While the normal birds are likely to infect each other, they are going to cause a major outbreak in the chicken farms in many cases.
Influenza, it's not a disease of human, it's an agricultural problem because you see that most of the chickens in the farm are dead because of influenza.So that actually can amplify quite a bit the influenza virus and also connect the influenza virus with us with the farmers that are taking care of the chickens, the dead chickens, so they can be infected as well, and then they can transmit it further.But the amplification of this virus is not by the duck so much by in the chicken farms.We are talking about many, many thousands of chickens in one location.
And monkeypox, I mentioned this earlier.We can see a virus which is transmitted among enemas.Rodents in Africa can be infected.Still not likely to affect us so much.But when you bring them to the pet store, this is the time that you can see that a virus that is not supposed to be in the United States, for example, to start with, going to be there in the connection between rodents that normally are not going to see each other and to infect each other is also taking place in such a pet store.
So here you can see some of the ways that we people can amplify emerging infectious diseases.
Explains how transportation technologies, especially ships and airplanes, move pathogens across continents and make local outbreaks global.
Speaker A
But I still need to tell you about the most important one.
Well, in the past, if you wanted to go from one place to another, you had to take your body and to start to walk, you had to be healthy in order to do so.The chance to transmit Pathogens this way, when you are walking from one place to another is not so high.
However, later on we start to have another technology.
Boats, ships that were able to bring people from one place to another.And here, if they are sick, they are going to lie somewhere to be recovered during the journey.
And they can transmit viruses and other pathogens from one place to another.Nado Cortez that came to the Americas with soldiers, few horses, and two viruses, smallpox and measles.Someone there was ill.The virus was able to be transmitted from one person to another.In some cases, viruses like smallpox can stay for long period of time on blankets.
So another way that you can transmit the virus by fomites.And this is the way that the Native Americans got the infection with smallpox and measles and killed by millions.Millions were killed by virus that was brought there throughout boats that were crossing the ocean.
Today.Today, everybody want to fly.
So if you are in the Far east and you want to go to the Middle east, well, I mean, in the old days, probably had to take you like nine months when you were walking today, nine hours.
So you went to visit your boyfriend in the forest.You got something over there.
COVID 19 maybe.And when you're coming back by causal contact between people, you can infect them with the virus that was originated elsewhere.
Well, I mean, we know very, very well how they traveling by airplane was extremely effective in transmitting the COVID 19, for example, up to the level that we stop to travel by airplanes.
And that's actually an important way to reduce the transmission of viruses which exist in one place and not in another.
Well, with COVID 19, which is highly contagious, it was not working.
The virus was able to move quickly from one place to another.So closing the borders was not doing so much good.Today.
Air network is very, very busy.
In 1933, we had very few waves to cross the ocean by an airplane.In general, in the old days, when the air traveling was not so common, we probably had less infectious diseases after all.And some infectious diseases were able to be stopped in some location and not to move to other locations.Be a virus in the world.Viruses can move very, very easily.
By the airline industry, you are infected with the virus, and in all time you are in the other side of the world.
Recounts the 2003 SARS outbreak from animal origin to international spread through a hotel conference, then describes the public health response that stopped the epidemic.
Speaker A
Let me take you to the SARS virus of 2003, 2003, we realized that there is a coronavirus which is infecting people, killing like 10% of the infected people.And when we look to see where this virus is coming from, we realize first that this virus was originated from bats.
But we also found that there is this intermediate animal in the transmission and that was palm civet.Palm civet got infected from bats.Palm civets is used and as a source of meat in some restaurants.So the chef got infected with the SARS virus.While preparing the meat of this animal, the chef start to infect some people in the neighborhood.
And some of them went to see a doctor as they felt very, very ill.The doctor got infected from the SARS virus.And the doctor was not feeling so great.But he had a conference to attend a conference in Hong Kong.
So he decided to go there anyway.
He had a room in the ninth floor of the hotel.The conference administration booked the entire floor for people from the conference.This is the red.He was living in room 911.Well, at that time that was a special number.
And that's where he was living.And the morning went to have breakfast.He went through this elevator, went down.He started to feel very, very ill.He felt that he must vomit and run back to his room.
But when he was looking for a key, bam.He had an accident.He vomited on the carpet, tried to clean as much as possible.But the carpet was found later on to be full with viruses.
So the doctor was found later on dead in his room.But in this morning, other doctor that where part of the conference went back to their room and they stepped on the carpet.They got infected.And you can see exactly where the room is located, which means that they came from the elevator, they were trying to reach the room.And this region happened to have the same virus that was affecting them and make them to get sick.
So we had a conference with quite a lot of people that got infected.And at certain point they had to go back home.So this is international conference.So the index patient got the virus in Guangdong province in China.That was our physician that got the virus over there as it was treating patients.
And from here the virus was transmitted to a lot of different locations.Some participants stayed in Hong Kong and they got the infection in this hotel, starting an outbreak in Hong Kong.Another one went to Vietnam, other two went to Singapore.And the third one went to Singapore and take another flight to Germany.
And one went to the United States.And in all those cases we have outbreaks of salts.
One came back to his home in in Ireland.And we had two cases that came back to Canada.One of them to Toronto was a physician that came back ill. She infected her husband with this virus.Her husband felt so bad, they went to Mount Sinai Hospital.And over there, infected staff and patients.
And that was the first time that we realized that we have a major problem now.Toronto was the center of the outbreak.Many people here in our city, Toronto got infected again.You can see that in one step, the infection of the patient in Hong Kong brought the virus to many different locations.
To Asia, to Europe, to North America.So the virus moved to many different locations.In each of them it was able to to cause an outbreak in the United States, Australia and others.
And in some cases the outbreak was quite significant.Like in Hong Kong, that everything was started over there with quite significant number of deaths compared to the number of cases here in Canada, mainly Toronto.We had 251 confirmed infections and 43 deaths.Overall the number of confirmed cases is 8,096.And number of people killed is 774.
Which gave us like 10% lethality in confirmed cases.So the SARS is aggressive virus.No drugs, no vaccines were available, just good public health measures which in eradicate the virus in people.
So today nobody is infected.But you can find the virus in animals such as bat.
So this aggressive virus stop to infect people around July 2003.Most of those cases took place since April 2003.So we have few months of an outbreak that never came back.
So during the SARS epidemics, the WHO took a very strong public health measures and formally alert people from visiting Toronto.
Mel Assman, at that time the mayor of the city did not like it at all.But the who was right.that time when you were going to Pearson Airport.Well, nobody was there in the arrival section.
Yes, at that time people were very worried from us Canadians, maybe even more than from bioterrorism, which was an issue on the news at that time for Cape of aids.