Sunday, May 08, 2022

UK Reporting Another Imported (ex Nigeria) Case of Monkeypox


Geographic Range of Monkeypox - Credit WHO   


Although human infection with Monkeypox is rare outside of central Africa, in recent years we've seen a small - but growing - number of imported cases turn up in the United Kingdom, the United States, Singapore, and even Israel.  A few from the past 12 months include:

CDC & Maryland DOH Investigating An Imported Case Of Monkeypox (ex Nigeria)

CDC Issues HAN On Potential Exposure To Person With Confirmed Monkeypox Infection

CDC & Texas Confirm Monkeypox In US Traveler ex Nigeria

ECDC CDTR: 3rd Monkeypox Case In the UK

UK Health Secretary: 2 Cases Of Monkeypox In Wales

Most of these cases have come from Nigeria - where Monkeypox resurfaced in 2017 after an absence of nearly 40 years - resulting initially in more than 200 confirmed and suspected cases. Fortunately, the West African Monkeypox virus is considered to be less virulent, and less easily transmitted, than its Central African counterpart (cite).

While it is rare to see ongoing transmission of Monkeypox from imported cases, last year the UK saw 2 people infected after a family member returned from Africa with the virus. 

Although the primary animal reservoir for Monkeypox remains unknown, humans can become infected in the wild from an animal bite or direct contact with the infected animal’s blood, body fluids, or lesions, but consumption of under cooked bushmeat is also suspected as an infection risk. 

Human-to-human transmission can also occur. This from the CDC’s Factsheet on Monkeypox:

The disease also can be spread from person to person, but it is much less infectious than smallpox. The virus is thought to be transmitted by large respiratory droplets during direct and prolonged face-to-face contact. In addition, monkeypox can be spread by direct contact with body fluids of an infected person or with virus-contaminated objects, such as bedding or clothing.

Research over the past few years suggests that Monkeypox outbreaks are becoming more frequent, and getting larger, probably due to the waning immunity from smallpox vaccinations which were discontinued 4 decades ago. A few recent reports include:

WHO Update & Risk Assessment On Monkeypox In The DRC

WHO: Modelling Human-to-Human Transmission of Monkeypox

All of which brings us to the UKHSA's report, released yesterday, on their latest imported case.  I'll have more after the break.

Monkeypox case confirmed in England
The UK Health Security Agency (UKHSA) can confirm an individual has been diagnosed with monkeypox in England.

From:UK Health Security Agency Published 7 May 2022

The patient has a recent travel history from Nigeria, which is where they are believed to have contracted the infection, before travelling to the UK.

Monkeypox is a rare viral infection that does not spread easily between people. It is usually a mild self-limiting illness and most people recover within a few weeks. However, severe illness can occur in some individuals.

The infection can be spread when someone is in close contact with an infected person; however, there is a very low risk of transmission to the general population.

The patient is receiving care at the expert infectious disease unit at the Guy’s and St Thomas’ NHS Foundation Trust, London.

As a precautionary measure, UKHSA experts are working closely with NHS colleagues and will be contacting people who might have been in close contact with the individual to provide information and health advice.

This includes contacting a number of passengers who travelled in close proximity to the patient on the same flight to the UK. People without symptoms are not considered infectious but, as a precaution, those who have been in close proximity are being contacted to ensure that if they do become unwell they can be treated quickly. If passengers are not contacted then there is no action they should take.

Dr Colin Brown, Director of Clinical and Emerging Infections, UKHSA, said:

It is important to emphasise that monkeypox does not spread easily between people and the overall risk to the general public is very low.

We are working with NHS England and NHS Improvement (NHSEI) to contact the individuals who have had close contact with the case prior to confirmation of their infection, to assess them as necessary and provide advice.

UKHSA and the NHS have well established and robust infection control procedures for dealing with cases of imported infectious disease and these will be strictly followed.

Dr Nicholas Price, Director NHSE High Consequence Infection Diseases (airborne) Network and Consultant in Infectious Diseases at Guy’s and St Thomas’, said:

The patient is being treated in our specialist isolation unit at St Thomas’ Hospital by expert clinical staff with strict infection prevention procedures. This is a good example of the way that the High Consequence Infectious Diseases national network and UKHSA work closely together in responding swiftly and effectively to these sporadic cases.

Initial symptoms include fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion. A rash can develop, often beginning on the face, then spreading to other parts of the body. The rash changes and goes through different stages before finally forming a scab, which later falls off.

While pretty far down out pandemic worry list, three months ago in PLoS NTD: The Changing Epidemiology of Human Monkeypox—A potential threat? we looked at a systemic review in PLoS Neglected Tropical Diseases, which examined recent trends in the spread and epidemiology of Monkeypox, and found the threat is growing.

The authors wrote:

Our review shows an escalation of monkeypox cases, especially in the highly endemic DRC, a spread to other countries, and a growing median age from young children to young adults. These findings may be related to the cessation of smallpox vaccination, which provided some cross-protection against monkeypox, leading to increased human-to-human transmission. The appearance of outbreaks beyond Africa highlights the global relevance of the disease. Increased surveillance and detection of monkeypox cases are essential tools for understanding the continuously changing epidemiology of this resurging disease.

While largely overshadowed by the first SARS epidemic, in 2003 we saw a rare multi-state (Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconsin) Monkeypox outbreak when a Texas animal distributor imported hundreds of small animals from Ghana, which in turn infected prairie dogs that were subsequently sold to the public (see MMWR Update On Monkeypox 2003).

By the time that outbreak was quashed, the U.S. saw 37 confirmed12 probable, and 22 suspected human cases. Among the confirmed cases 5 were categorized as being severely ill, while 9 were hospitalized for > 48 hrs; although no patients died (cite).

Like all viruses, Monkeypox continues to evolve and diversify, as discussed in the 2014 EID Journal article Genomic Variability of Monkeypox Virus among Humans, Democratic Republic of the Congo, where the authors cautioned:

Small genetic changes could favor adaptation to a human host, and this potential is greatest for pathogens with moderate transmission rates (such as MPXV) (40). The ability to spread rapidly and efficiently from human to human could enhance spread by travelers to new regions.

All of which makes Monkeypox one of the emerging zoonotic viruses we watch with considerable interest.