To add to the many problems we face due to our destruction of the natural world, along comes another Zoonotic disease from the tropics, this time related to the globally eliminated Smallpox. This is the first time chains of transmission have occurred outside Africa and it seems to be spreading around the world. Should I be worried? Let’s have a look at Monkeypox.
Where has it come from?
This review of a recent outbreak in Nigeria sums it up nicely –
“The wane in herd immunity as a result of cessation of smallpox vaccination, increased contact between humans and potential MP animal reservoir hosts as a result of climate change and deforestation, bush meat consumption, and inadequate health and research infrastructure among others may have created an immunological and ecological niche for MP to re-emerge” ..….”Therefore, MPXV is a very serious re-emerging pathogen with global outreach”
It is called MonkeyPox as it was first described in 1958 after an outbreak in cynomolgus monkeys kept for research into polio after their import from Asia to Copenhagen.
Following its isolation it was found to be circulating in many mammal species. In other words, it is not particular to monkeys. It is not related to the similarly named Chickenpox which comes from a different family of viruses – so cross immunity is not going to be helpful.
It does not mutate rapidly like SARS-Cov-2, though slow evolution has clearly made it more likely to infect humans. Like COVID, it is diagnosed using PCR techniques, this time from fluid swabbed from the vesicles.
So far (27th May) in the UK there are about 101 cases, but this is increasing gradually and is likely to be the tip of the iceberg. It’s spreading across Europe with over 100 cases in Spain and now to the USA, and like COVID19, likely soon to be everywhere. In a pandemic fatigued world, Monkeypox is very much being played down right now, and perhaps rightly, as it is far less contagious than SARS2, but has some features which make it a concern.
It will, as usual, hit those who are immunocompromised, the elderly, the unwell and all those who will be moved neared the ‘edge of life’s cliff’ by another unpleasant illness.
Unfortunately, it is more severe in children and pregnant women, though there have been no cases in those groups outside Africa, so far.
Anyone aged under 50 will not have had smallpox vaccination (or smallpox itself) which offers 85% protection against Monkeypox. Smallpox, we should remember killed 30% of those infected; MP is far less severe. The WHO report a mortality of 10% for the Congo strain and 1% for the West Africa strain which is circulating here. Figures vary but those sort of mortality rates are concerning if they are replicated on any large scale.
What’s it like to have Monkey Pox?
The incubation period, the time in between contact and noticeable symptoms varies from 5-14 days, to be followed by 0-5 days of symptoms in the ‘invasive’ phase. This include severe headache, chills, swollen glands, back pain and fever and is followed by the skin features.
Rash of Monkeypox.
These start with red patches which become swollen to vesicles, which then become pus laden and form crusts which fall off as healing takes place. The face is most affected and the spots can vary from 1 to hundreds. The illness resolves after a significant 2-4 weeks. These pictures show what the pox look like and how they grow, crust over and heal. Scarring is possible, though far less than the disfiguring Smallpox.
The first human MP case was noticed in the Democratic Republic of Congo in 1970, and there was a subsequent outbreak in Nigeria since 2017 with 500 cases so far. Mortality among cases appeared high, in between 3-6%, but this will not account for the many milder infections which don’t get counted. The first time it was noticed outside Africa was in 2003.
An outbreak in the USA led to dozens of cases linked to prairie dogs and pets which had been in contact with Gambian pouched rats and dormice, which had, I kid you not, been imported to the US from Ghana, as pets!
This provides another insane example of the lack of regulation vital to control otherwise dangerous international markets. Buying and importing live animals from Africa as pets is about as daft as going over there to kill them for ‘sport’.
The natural reservoir has not been identified; many species have antibodies and the only active infection was found in a squirrel. Transmission between humans requires the sort of contact that exists between family members, close physical contact, and of course, caring for the unwell. Mercifully, spread is less likely than with COVID19, with most spread occurring with direct contact of skin to infected skin and less thorough the respiratory route.
What we don’t know
We don’t know if these outbreaks are due to increased travel from Africa, or if they are due to increased cases there. There have been significant outbreaks in the past in Nigeria, last in 2017-18 affecting 17 states, where MP seems to have stepped into the ecological niche left by the extinction of Smallpox. Neither do we fully understand the mode of transmission.
Although skin to skin contact is the most likely way its spread, and many of those infected here so far are from the gay community, MP is not primarily a sexually transmitted disease. We also need to know the case mortality rate which so far varies from time to time and place to place – the variant circulating here has been described as having a 4% mortality rate, though picking up less severe cases will mean that number falls.
The we have to look at the genetic to see how the virus is evolving. This will need surveillance similar to that which defined the emerging variants and their characteristics with SARS-Cov-2. It is said to mutate slowly, but I heard that early in the COVID19 pandemic. We shall see.
What to do?
Anyone who has sex with multiple contacts should be aware of the symptoms and signs and if worried call 111 or their local sexual health clinic, isolate and wait for contact tracing. Anyone with an odd skin rash similar to Chicken Pox should also seek advice and help, isolate, protect any vulnerable contacts, and do everything to minimise risk of spread. If you are vulnerable, pregnant, on immunosuppressive drugs, then treatment is available for cases and smallpox vaccination available for vulnerable contacts.
If would be helpful to offer more assistance to African nations where the condition is more common, and where more cases have been noted in children.
When it comes to Zoonotic illnesses, we are all in it together. Centuries long Western abuse in Africa laid the foundations of economic and structural problems which encourage spillover to take place and to take hold, as it has done for others, most notably HIV.
Surely it goes without saying not to buy pets from abroad?
How much to worry?
So for most of us, not much right now. It is however, another example of spillover of infections from the natural world which have defined the last couple of years and have been responsible for world changing plagues in the past. Increasing spread means more viruses exist and leads to more potential for the emergence of more transmissible variants, It hints at pandemics to come.
There have been no cases in the vulnerable or in children in the UK so far, so we shall have to see how this plays out. The predominance in men who have sex with men means its not a very efficient spreader, needing significant personal contact.
Of course, I await the inevitable conspiracy theories regarding its origin, spread, which will be fuelled by the likely emergency of more specific mRNA vaccines for those who need them.
Till then, its watch this space.
Thanks for reading this post. If you have any comments or questions then do leave them in the box below and I’ll respond as soon as I can. Till next time, I wish you the best of health!