Monkeypox is a rare infection that is mainly spread by wild animals in parts of west or central Africa (NHS website, 2022). It was first discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research, hence the name ‘monkeypox.’ The first human case of monkeypox was recorded in 1970 in the Democratic Republic of Congo during a period of intensified effort to eliminate smallpox (Moore and Zahra, 2022). Since then, monkeypox has been reported in humans in other central and western African countries (Centers for Disease Control and Prevention (CDC), 2022). Before the current outbreak, there were seven cases of monkeypox in the UK between 2018 and 2021. Four of these were imported, two cases had been in household contacts of confirmed cases, and one case was in a healthcare worker involved in the care of an imported case (UK Health Security Agency (UKHSA), 2022a).
Outbreak outside Africa
In the UK on 7 May 2022, one case was reported, linked to travel from Nigeria. On 14 May 2022, a familial cluster of two cases of monkeypox was reported in the UK (UKHSA, 2022a). These cases had no relation to the travel-related case previously reported (European Centre for Disease Prevention and Control (ECDC) (2022). Since the UKHSA reported these cases, several other European countries have reported cases of monkeypox.
The ECDC (2022) has since announced a multi-country outbreak of monkeypox affecting the UK, EU/EEA states and North America. As of 19 May 2022, 38 cases had been confirmed worldwide, 37 of which have no history of travel to endemic countries. Of these, 26 cases had been confirmed in the following EU/EEA countries (ECDC, 2022):
- Belgium: 2
- France: 1
- Italy: 1
- Portugal:14
- Spain: 7
- Sweden: 1.
In the UK, nine cases had been confirmed. In North America, three cases have been confirmed in Canada (2), and the US (1).
In addition, Portugal reported another 20 suspected cases, and Spain reported another 23 suspected cases, which were awaiting laboratory confirmation. Health authorities across countries have stated that further cases are expected (ECDC, 2022).
At the time of writing, the UKHSA has detected 104 additional cases of monkeypox in England. As of 12 June, this brought the total number of cases confirmed in the UK to 470. There are currently 452 confirmed cases in England, 12 in Scotland, 2 in Northern Ireland and 4 in Wales (UKHSA, 2022b).
Most cases have been in young men, many self-identifying as men who have sex with men (MSM), and none with recent travel history to areas where the disease is endemic. No deaths have been reported so far, and only two cases have been admitted to hospital for reasons other than isolation (ECDC, 2022).
Most cases presented with lesions on the genitalia or peri-genital area, indicating that transmission likely occurs during close physical contact during sexual activities. This is the first time that chains of transmission of monkeypox have been reported in Europe without known epidemiological links to west or central Africa, where the disease is endemic.
Monkeypox pathogen
The World Health Organization (WHO) (2022) has identified monkeypox virus as an enveloped double-stranded DNA virus that belongs to the Orthopoxvirus genus of the Poxviridae family. There are two distinct genetic clades of the monkeypox virus—the central African (Congo Basin) clade and the West African clade. The Congo Basin clade has historically caused more severe disease and was thought to be more transmissible. Cameroon is the only country where both virus clades have been found (WHO, 2022).
Various animal species have been identified as susceptible to monkeypox virus. These include Congo rope squirrels, African tree squirrels, Gambian pouched rats, dormice, non-human primates, and other species. Uncertainty remains on the natural history of monkeypox virus and further studies are needed to identify the exact reservoir(s) and how virus circulation is maintained in nature (WHO, 2022).
Transmission
The risk of catching monkeypox in the UK is low.
It can be caught from infected wild animals in parts of west and central Africa. It is thought to be spread by rodents, such as rats, mice, and squirrels. It is suggested that people can catch monkeypox from an infected animal if bitten or when in direct contact with blood, body fluids, spots, blisters, or scabs (NHS website, 2022). It may also be possible to catch monkeypox by eating meat from an infected animal that has not been cooked thoroughly, or by touching other products from infected animals (such as animal skin or fur).
Monkeypox can also be spread through touching clothing, bedding or towels used by someone with the monkeypox rash, touching monkeypox skin blisters or scabs. It can be transmitted through the coughs or sneezes of a person with the monkeypox rash, but ‘transmission via droplet respiratory particles usually requires prolonged face-to-face contact, which puts health workers, household members and other close contacts of active cases at greater risk’ (WHO, 2022).
Symptoms
Monkeypox usually takes between 5 and 21 days for the first symptoms to appear (NHS website, 2022). In humans, the symptoms are similar to but milder than the symptoms of smallpox. Monkeypox typically begins with fever, headache, muscle aches and exhaustion. The main difference between the symptoms of smallpox and monkeypox is that monkeypox causes lymph nodes to swell (lymphadenopathy), while smallpox does not. The incubation period (time from infection to symptoms) for monkeypox is usually 7 to 14 days but can range from 5 to 21 days (CDC, 2022).
Within around 1 to 3 days of the first symptoms of fever, the patient will develop a rash, often beginning on the face and then spreading to other parts of the body. Lesions progress through the following stages: macules, papules, vesicles, pustules and scabs. The illness typically lasts for 2 to 4 weeks. In Africa, monkeypox has been shown to cause death in as many as 1 in 10 persons who contract the disease (CDC, 2022).
Prevention and treatment
The immediate recommendations made by the ECDC (2022) request that public health institutions/authorities and community-based organisations should take steps to raise awareness of the potential spread of monkeypox in the community, especially among MSM, those who engage in casual sex, or who have multiple sexual partners. Individuals engaging in casual sex or who have multiple sexual partners who are not MSM should also be vigilant. Any persons presenting with symptoms indicative of monkeypox should seek specialist care and should abstain from sexual activities or any other type of activities involving close contact until monkeypox is either excluded or the infection is resolved. Suspected cases should be isolated and tested and notified promptly. Backwards and forwards contact tracing should be initiated for positive cases, and exposed mammalian pets should be quarantined.
‘This is the first time that chains of transmission of monkeypox have been reported in Europe without known epidemiological links to west or central Africa, where the disease is endemic’
Clinical care for monkeypox should aim to alleviate symptoms, manage complications and prevent long-term sequelae. Patients require fluids and food to maintain adequate nutritional status. Secondary bacterial infections should be treated as indicated (WHO, 2022). If smallpox vaccines are available in the country, vaccination of high-risk close contacts should be considered after a risk-benefit assessment. For severe cases, treatment with a registered antiviral can be considered. Vaccination against smallpox was demonstrated through several observational studies to be about 85% effective in preventing monkeypox (WHO, 2022). Thus, prior smallpox vaccination may result in milder illness.
Conclusion
The risk of catching monkeypox in the UK is low, but vigilance is needed. The UKHSA is working with UK and global partners to investigate and better understand the virus, its transmission and treatments. Monkeypox has now been declared a notifiable disease. The UKHSA (2022b) has stated that rapid diagnosis and reporting is key to containing any further spread of the virus.