Monkeypox : epidemiological update

We’re going to talk today about monkey Pox as there’s been some more information. Coming out about the most recent outbreak. In ten countries worldwide with over 127. And people infected that have been confirmed. Monkey pox is a DNA virus that is in the Orthopox virus family. It’s actually related to smallpox but not as dangerous. So some key differences to know is. That, first of all, it is a DNA virus. And whereas with Sarskovy two, which had. 30,000 RNA codes, basically, the monkey pox is a double stranded DNA virus and it’s much larger.

So probably more pairs to sequence and probably more genes to sequence as well. It’s probably been infecting humans for a very long time, but it was first. Isolated in 1958 in crab eating the Cox. These are like monkeys. And that’s where the name monkey pox kind of stuck. Now it made its jump into humans. At least that we could see in the Democratic Republic of Congo in the 1970s.

That’s the Central African Republic. And as you can see here from. This webpage, which will put a link in the description below, the Democratic Republic of Congo is where this was first discovered. And this is where we see the. Central African strain of the monkey pox virus. Now, there is a West African strain which you can see here in these other countries in West Africa. And that’s important to understand because the. Death rates from infection from the Central. African strain is 10%, whereas the West African strain is about 1%. And at least early on now, as.

We’Re looking at these viral infections in. The UK, the United States, they seem to be related more to the West African strain. The other thing that’s really important to. Understand is that even though it has. The word monkey in the name monkey pox, it’s kind of a misnomer because actually these types of infections come from any small African mammals and rodents. And that was highlighted with the recent.

And let’s talk about that, and that. Will set the stage for where we are right now. So back in January of 2004, there. Was a paper that was published in. The Lancet Infectious Diseases titled Human Monkeypox, an Emerging Zoonosis and Xenosis is simply a disease that comes from animals. And let’s read this abstract here because I think it’s really interesting. Human monkey pox, it says here, is a rare viral zumosis endemic to central.

And Western Africa that has recently emerged. In the United States. Of course, this was published about 20 years ago. Laboratory diagnosis is important because the virus. Can cause disease that is clinically indistinguishable from other pox like illnesses, particularly smallpox and chicken pox. Although the natural animal reservoir of the monkey pox virus is unknown, rodents are the probable source of its introduction into the USA, a clear understanding of the virulence and transmissibility of human monkeypox has been limited by inconsistencies in epidemiological investigations.

Infection in human beings since the eradication of smallpox in the 1970s. We’ll pause there understand that the eradication. Of smallpox in the 1970s was mostly. In part due to vaccines and as. You’Ll see later it was those vaccines that also had an import in reduction of monkeypox. Let’s go on. There is currently no proven treatment for human monkey pox and questions about its potential as an agent of bioterrorism persist. So the good news is that scientists.

Have been looking at this particular virus. For some time and they’ve understood quite. A bit about it. This is unlike what happened two years. Ago when we were looking at the. Brand new virus of Sarskovie two. Also interesting here is that there was the spectrum raised of this virus being used as bioterrorism so we’ll get into. The symptoms in a little bit but. I wanted to take you back to. The year 2003 because it was this.

Year that there was an outbreak in the United States of monkey pox and this wasn’t because of animals that were transported from endemic region of central Africa that was transported and was brought into the United States and caused animal to human infections. There was a study that was done. Looking at those of the ones that had medical records, 34 of them were. Researched, and they were found in almost. Every case to have a rash that. Progressed to a raised lesion, that progressed.

To a postular lesion, as we’ll show. Some pictures of later. And that lasted and crusted over and took about two to three weeks for that to completely go away. This would show up on the trunk. Of the body, that’s a central portion. Then go to the arms, even the. Palms and soles, and then crossed over. After a long period of time. There was further investigation done during this time to see just how far this infection had gone. And what was interesting is that they had picked up on a number of.

People in this case, particularly three individuals that were positive for the antibodies against. Monkey pox, but never knew that they had symptoms. And what it came out was that. They had actually been vaccinated against smallpox. And get these years here. This is really interesting. One of them was 13 years prior. Another one was 29 years prior to. The infection with the monkey pox. And another individual 48 years prior was. Vaccinated with smallpox vaccine.

And that seemed to confer protection against symptomatic monkeypox disease. So, as you can see, this is. Going to be an important discussion when. We talk about treatment and prevention here at the end. But let’s talk about what are the. Symptoms of monkey pox and what you. Would do to look for those. So when they looked at the outbreak. In 2003 in the United States, they. Noticed that those that had the monkey pox virus had a rash 97% of. The time, fever 85% of the time.

Chills 71% of the time, enlarged lymph nodes 71% of the time, headaches 65% of the time, and muscle aches 56% of the time. And here you can see what the progression of the skin lesions look like. As posted here by the UK Health. Security Agency early on. This is about a three millimeter diameter vesicle. It looks like it’s fluid filled, it’s raised here. It turns into a small pustule about 2 diameter. You can see here, this is an. Umbilicated, which means it looks like there’s an umbrellais in the center of it. This is a pustule about three to 4 diameter.

In the center, it’s about 5 diameter. Here we have some encrusting of a mature lesion. And then finally, here what we call a disqualiff reaction where the skin comes off the top and it’s partially removed scab. So this is the type of lesions.

That we would see and there would. Be multiple of these. Okay, let’s talk about how this virus gets transmitted now. And classically, there are two ways that. This can be transmitted, there. It’s through humans and through animals, and. Of course, close contact, touching sores, especially if they’re open or even touching the clothes that the patient was wearing and. Picking it up from there. In terms of animals, it would be. Much of the same.

So close contact but also biting and scratching or even eating the meat of those animals. And we’re talking about small animals like rodents, Prairie dogs, things of that nature. Now, in terms of incubation, that’s another. Issue and it may depend on the mode of transmission. For instance, it would be shorter incubation. Period if it was something like scratching. Or biting and it’s been set up to nine days. So for biting and scratching, 90 day. Incubation period before you would start to actually see this. That’s quite a long period of time.

The touching, however, can be up to. 13 days even longer. Now, classically, the RNA that we’ve been. Talking about for some time in terms. Of transmission from coronavirus can be above one or two. Generally speaking, for monkey pox, it’s somewhere between zero and one which means that. These outbreaks tend to fizzle out because the person can not always reliably transmit. This virus because it’s obvious when the. Person has the virus and it’s easy. To isolate these patients. What’s notable here and that you should understand is that large respiratory droplets have also been implicated in the transmission from.

Human to human of monkey pox. And specifically, it’s not like it would. Be with measles or even sarskovie too. But for instance, if you are within. 6Ft of somebody, you would have to be there for at least three plus. Hours to have reliable transmission. This is classically what is being noticed. This is classic.