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Monkeypox: What we know about the smallpox-like virus spreading in the UK

This rare smallpox-related virus causes flu-like symptoms and a nasty rash, and it can be deadly.
This rare smallpox-related virus causes flu-like symptoms and a nasty rash, and it can be deadly.   -   Copyright  Courtesy WHO/Nigeria Centre for Disease Control
By Natalie Huet

Four more cases of monkeypox - a rare viral infection related to smallpox - have been confirmed in England, bringing the total so far to seven, British health authorities said on Monday.

The UK Health Security Agency (UKHSA) said three of the new cases were detected in London and one in the northeast of England.

The new cases do not have known connections with the two additional ones reported on May 14 and with the first case announced on May 7, which was found in a person who recently flew into the UK from Nigeria.

However, the UKHSA said it was investigating links among these four new cases, who all appear to have been infected in London and all self-identify as gay, bisexual, or men who have sex with men.

"We are particularly urging men who are gay and bisexual to be aware of any unusual rashes or lesions and to contact a sexual health service without delay," said Dr Susan Hopkins, the agency's chief medical adviser.

The UKHSA recommended particularly looking out for lesions on genitalia.

Six patients are being treated in specialist infectious disease units at Guy’s and St Thomas, St Mary’s Hospital, and the Royal Free Hospital in London, as well as the Royal Victoria Infirmary in Newcastle-upon-Tyne. One case is isolating and does not currently require hospital treatment.

What are the symptoms of monkeypox?

Monkeypox is a relative of smallpox, a disease that was eradicated in 1980, but is less transmissible, causes milder symptoms and is less deadly.

The illness typically lasts for two to four weeks and symptoms can appear anywhere from five to 21 days after infection.

Monkeypox symptoms usually begin with a mix of fever, headaches, muscle aches, backache, chills, exhaustion, and swollen lymph nodes.

This latter symptom is typically what helps doctors distinguish monkeypox from chickenpox or smallpox, according to the World Health Organization (WHO).

Once you have a fever, the key feature of monkeypox, a nasty rash, tends to develop one to three days later, often starting on the face and then spreading to other parts of the body.

The number of lesions may range from a few to thousands.

The lesions will go through an ugly ripening process, from macules (flat lesions) to papules (raised lesions), vesicles (fluid-filled lesions), then pustules (pus-filled lesions) and then finally scabs (crusty lesions) before eventually falling off.

WHO /Mark V. Szczeniowski
File - A 7-year-old Zairian girl with monkeypox in the acute stage, day 7 of rash, and monkeypox in a 3-year-old Zairian boy with rash in the scabbing stage, DRC, 1970-1977.WHO /Mark V. Szczeniowski

Why is it called monkeypox?

Monkeypox virus belongs to the Orthopoxvirus genus in the family Poxviridae. It was first discovered in 1958 when two outbreaks of a pox-like disease occurred in lab monkeys kept for research, hence the name.

But monkeys might not be the ones to blame for outbreaks, and the natural reservoir of monkeypox remains unknown, though the WHO says rodents are the most likely.

“In Africa, evidence of monkeypox virus infection has been found in many animals including rope squirrels, tree squirrels, Gambian poached rats, dormice, different species of monkeys,” says the UN health agency.

Where is monkeypox found?

Human monkeypox primarily causes outbreaks in the tropical rainforest regions of Central and West Africa and is not typically seen in Europe.

The Democratic Republic of the Congo (DRC) had the first recorded human case of monkeypox in 1970.

Since then, cases have been reported in 11 African countries: Benin, Cameroon, the Central African Republic, the Democratic Republic of the Congo, Gabon, Ivory Coast, Liberia, Nigeria, the Republic of the Congo, Sierra Leone, and South Sudan.

The first outbreak of monkeypox reported outside of Africa was linked to the importation of infected mammals in 2003 in the United States, according to the US Centers for Disease Control and Prevention (CDC).

More recently, in 2018 and 2019, two travellers from the United Kingdom, one from Israel, and one from Singapore, all with travel history in Nigeria, were diagnosed with monkeypox following a large outbreak there, according to Europe’s own health agency, the European Centre for Disease Prevention and Control (ECDC),

How do you catch monkeypox?

You can catch the virus from the bite or scratch of an infected animal, by eating bush meat, being in direct contact with an infected human or touching contaminated bedding or clothing.

The virus enters the body through skin lesions, the respiratory tract, or the mucous membranes (the eyes, nose, or mouth).

Human-to-human transmission is thought to occur primarily through large respiratory droplets, which generally cannot travel more than a few feet, so prolonged face-to-face contact would be needed.

A child affected by monkeypox receives treatment at a centre of the NGO Doctors Without Borders, in Zomea Kaka, in the Central African Republic, October 18, 2018.CHARLES BOUESSEL / AFP

Should I be worried?

Monkeypox “is usually a mild self-limiting illness and most people recover within a few weeks,” the UKHSA said in its statement.

“It is important to emphasise that monkeypox does not spread easily between people and the overall risk to the general public is very low,” said Dr Colin Brown, the agency’s director of clinical and emerging infections.

The patients infected in England contracted the West African clade of the virus, which health officials say is mild compared to the Central African clade and has a case fatality ratio of around 1 per cent.

Although its symptoms are milder than those of smallpox, monkeypox has been shown to cause death in as many as 10 per cent of patients infected with the Congo Basin clade**,** compared to about 30 per cent for smallpox, according to WHO data.

Mortality is higher among children and young adults, and immunocompromised individuals are especially at risk of severe disease. 

Monkeypox during pregnancy may also lead to complications, congenital monkeypox, or stillbirth, the WHO warned on Monday.

"Milder cases of monkeypox may go undetected and represent a risk of person-to-person transmission," it said in a statement.

Treatment and prevention

There is currently no specific treatment recommended for monkeypox, and it usually goes away on its own.

Vaccination against smallpox is believed to be highly effective in preventing monkeypox, but because smallpox was declared eradicated more than 40 years ago, first-generation smallpox vaccines are no longer available to the general public.

A newer vaccine developed by Bavarian Nordic for the prevention of smallpox and monkeypox has been approved in the European Union, the United States and Canada (under the trade names Imvanex, Jynneos and Imvamune), and antivirals are also under development.