Saturday, May 14, 2022

UKHSA Reports 2 Monkeypox Cases In London - Route Of Exposure Under Investigation

Geographic Range of Monkeypox - Credit WHO

Less than a week after reporting an imported Monkeypox case (see UK Reporting Another Imported (ex Nigeria) Case of Monkeypox), the UKHSA is investigating two additional - unrelated - cases in London.  

Both belong to the same household, and the source of their infection is apparently unknown, and under investigation. 

This is a bit unusual outside of Central and West Africa - and since no travel history is mentioned - suggests there is a local source of exposure. That could be from an infected human, an imported small animal or pet, or even  contaminated imported `bushmeat' (see `Carrion’ Luggage & Other Ways To Import Exotic Diseases).

In 2003 the United States saw an unprecedented multi-state outbreak of Monkeypox when an animal distributor imported hundreds of small animals from Ghana, which in turn infected prairie dogs that were subsequently sold to the public (see 2003 MMWR Multistate Outbreak of Monkeypox --- Illinois, Indiana, and Wisconsin, 2003).

By the time this outbreak was quashed, the U.S. saw 37 confirmed, 12 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). 

Details on the cases are fairly scant at this time, but we should learn more in the days ahead.  I'll have a bit more after the break.

Monkeypox cases confirmed in England

Two individuals have been diagnosed with monkeypox in London, confirms the UK Health Security Agency (UKHSA).

From:UK Health Security Agency Published 14 May 2022

The cases live together in the same household. They are not linked to the previous confirmed case announced on 7 May. Where and how they acquired their infection remains under investigation.

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 people.

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.

One of the cases is receiving care at the expert infectious disease unit at St Mary’s Hospital, Imperial College Healthcare NHS Trust, London. The other case is isolating and does not currently require hospital treatment.

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

People without symptoms are not considered infectious but, as a precaution, those who have been in close proximity to the individuals are being contacted to ensure that, if they do become unwell, they can be treated quickly.

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

We have confirmed 2 new monkeypox cases in England that are not linked to the case announced on May 7. While investigations remain ongoing to determine the source of infection, it is important to emphasise it does not spread easily between people and requires close personal contact with an infected symptomatic person. The overall risk to the general public remains very low.

We are contacting any potential close contacts of the case. We are also working with the NHS to reach any healthcare contacts who have had close contact with the cases 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.

Professor Julian Redhead, medical director at Imperial College Healthcare NHS Trust, said:

We are caring for a patient in our specialist high consequence infectious diseases unit at St Mary’s Hospital. All of the necessary infectious control procedures have been followed and we are working closely with UKHSA and NHS England.


Initial symptoms of monkeypox 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, particularly the hands and feet.

The rash changes and goes through different stages before finally forming a scab, which later falls off.

There is no word on whether this is the milder West African clade, which generally produces milder illness, fewer deaths, and only limited human-to-human transmission, or the mnre aggressive Central African clade. 

While neither of them transmit easily from human-to-human, 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.

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.