Crew Health Advice: Mpox


The latest virus circulating is the rather attractively named Mpox. There's been a lot of information about Mpox in the media and coming right on the back of COVID-19, it's inevitable that people will be concerned.

This bulletin from Crew Health Partner Red Square Medical aims to answer some of the questions concerning the virus.

What we need to know

  1. There are two strains (clades) of Mpox. The Congo Basin clade has a 10% fatality rate, and the West African clade runs at about 1% fatality rate. In this outbreak, all cases have been confirmed to be the West African clade. Fatalities are largely due to limited resources and poor access to healthcare. 
  2. Fatalities outside Africa are rare as people have access to better healthcare and drugs. 
  3. Mpox is zoonotic, which means it normally passes from monkeys and small mammals, such as rodents, to humans. 
  4. Most outbreaks in humans can be traced back to travel in affected areas (Central/West Africa), consuming contaminated meat or importing exotic pets (generally illegal activity). For instance, an outbreak of 71 cases in the USA in 2003 was traced back to Gambian rats sold as exotic pets. 
  5. It rarely passes from human to human, but it can. 
  6. Mpox is completely different to COVID, mostly because we already know how it operates. We already have vaccines available if needed and drugs such as Cidofovir can help with symptoms. 
  7. Anyone who has had the smallpox vaccine (if you were born prior to 1971 in the UK) may already have some immunity. But, the effectiveness of vaccines does reduce over time and cases of mpox were predicted to increase to fill the gap left by the eradication of smallpox. 

What to look for

One of the 'great' things about mpox is that people develop some very specific and distinctive symptoms before they become infectious. This helps massively in keeping cases contained.

The incubation period is a long 5 to 21 days from infection to the onset of symptoms and it generally starts (like so many viruses) with flu-like symptoms. So expect to see fever, aches and pains and distinctive swollen lymph nodes. 

The rash will start within 1-3 days after the fever and it goes through 5 stages - macules, papules, vesicles, pustules and finally scabs that will fall off. 

How it spreads

Pox viruses rarely transmit before the onset of symptoms which helps to contain the spread. As we said earlier, Mpox is most likely to transmit through being scratched or bitten by something small and furry - rats, squirrels, non-human primates, black-tailed prairie dogs, African brush-tailed porcupines, pigs, shrews or rabbits. 

But it can spread from person to person though:

  1. Respiratory droplets and aerosols from prolonged face-to-face contact
  2. Direct contact with bodily fluids or monkeypox lesions
  3. Indirect contact with contaminated items such as clothing or bedding

This means that the most common person to person infection is of people sharing a home with someone who has mpox, or healthcare workers. However, it takes a lot of virus (viral load) to transmit. 

It's also what's known as an enveloped virus, which happily means that normal soap, detergent and disinfectants will kill it off nicely. 

This most recent outbreak has been traced back to a large 'superspreader' festival in Antwerp. Mpox isn't sexually transmitted specifically, but if there's a lot of direct contact, and you're breathing all over each other, then it's likely to be passed on. 

The word in medical circles is it's unlikely that the virus has mutated and thought that the outbreak is being driven by more environmental, social and behavioural factors. 

What can you do?

Be vigilant and aware of the symptoms. 

  1. Personal hygiene is paramount... something we already know from COVID. Wash and/or sanitise your hands regularly. 
  2. Be careful with who you are in very intimate contact. 
  3. If you're bitten or scratched by any African rodents or small mammals, seek medical advice. 
  4. On ship, especially if you've called into port in West Africa, be alert for vermin onboard. 
  5. If you suspect you are developing symptoms, isolate straight away and seek medical advice. 

Additional Resources

There is a useful free training course circulated from the World Health Organisation Monkeypox: Epidemiology, preparedness and response for African (

Additional Information and FAQ on Mpox from the WHO

Monkeypox (

Monkeypox (

Red Square Medical

Crew Health partner Red Square Medical provides 24/7 Operational and Clinical support to Shipping companies to help reduce their risk and take the hard work out of the provision of medical care onboard ships. As well as our 24/7 services, we provide medical audits, medical preparedness plans and training courses/programs. Designed and delivered by seafarers for seafarers. Home (


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Liz Baugh, Red Square Medical