Why monkeypox outbreak has scientists on high alert

　　Why monkeypox outbreak has scientists on high alert

　　In the decades following the first human cases of monkeypox infection, monkeypox outbreaks have rarely occurred outside the African continent.

However, since May this year, monkeypox cases have been reported in many non-monkeypox-endemic countries around the world.

　　According to statistics from the infectious disease database established by researchers from Oxford University in the United Kingdom, Harvard Medical School in the United States and other institutions, as of the 24th, monkeypox cases have been found in at least 16 countries outside Africa, with a total of more than 170 confirmed cases and 87 suspected cases. example.

The sudden and rapid spread of monkeypox in non-endemic countries has made researchers highly vigilant.

Report of cases in non-endemic countries 'unusual'

　　Since the first human case of monkeypox infection in Congo (DRC) in 1970, monkeypox has mainly been endemic in western and central Africa.

Most of the cases reported globally so far are distributed in African countries such as Congo (Kinshasa), Congo (Brazzaville), Central African Republic, Nigeria, and Cameroon.

　　However, since the infection cases appeared in the UK at the beginning of this month, the number of countries outside Africa reporting monkeypox cases and the number of infected cases has continued to increase. At present, the UK, Spain, Portugal and other European countries have relatively serious monkeypox infections, and many infected people do not have monkeypox endemic areas. Travel history.

　　The World Health Organization recently said the emergence of monkeypox cases in multiple non-endemic countries without direct travel links to disease-endemic areas is an "atypical" situation.

As surveillance expands, it is possible that more cases will be detected in the future in countries where cases have been reported and in other countries.

　　Paul Hunter, a well-known expert in the field of microbiology and infectious disease control in the United Kingdom and a professor of medicine at the University of East Anglia, said in an interview with Xinhua News Agency that although there have been thousands of monkeypox cases in Africa in recent years, there are many non-monkeypox cases in the world. "Sustained community transmission, human-to-human transmission is unusual" in pox-endemic countries.

　　There does not appear to be a clear link between the majority of monkeypox cases reported so far, implying that multiple chains of community transmission may already exist.

Monkeypox virus infection is often easy to spot, in part because it causes skin lesions, said epidemiologist Andrea McCollum, who leads the poxvirus team at the Centers for Disease Control and Prevention.

It would be especially "disturbing" if monkeypox could spread asymptomatically, as it would make the virus harder to trace.

closely related to smallpox virus

　　The monkeypox virus is a "close relative" to the smallpox virus, which has been raging for thousands of years in human history, and belongs to the genus Orthopoxvirus of the Poxviridae family.

Scientists first discovered the virus in 1958 in a group of monkeys used for research, when the monkeys developed a "pox-like" infectious disease, from which the monkeypox virus got its name.

"Monkeypox is a virus that's been known to exist for a long time, and it's only become a concern with the eradication of smallpox," said Professor Hunter, who has studied infectious diseases in the African region for many years.

　　Studies have shown that the smallpox vaccine is 85% effective in preventing monkeypox.

Some scientists believe that immunity to monkeypox has also declined since the World Health Organization announced the eradication of smallpox in 1980, which is one reason why monkeypox infections have increased over the past few decades.

The population with weakened or no immunity to the virus has grown every year since smallpox was eradicated, said Raina McIntyre, an infectious disease scientist at the University of New South Wales in Australia.

　　Scientists are still looking for answers to the reasons for the sudden outbreak of monkeypox and clues to its spread.

WHO data shows that the West African branch of monkeypox virus has a case fatality rate of about 1%, while its Congo Basin branch has a fatality rate of 10% and is more contagious.

On the 19th, Portuguese researchers released preliminary genome data of monkeypox virus detected locally.

The data showed that the monkeypox virus found locally is related to the West African branch.

　　The researchers say this is still early genomic data, and questions such as how the virus responsible for the current outbreak is different from the West African branch, and whether the viruses found in different countries are related to each other, remain unknown.

Answering these questions will help understand whether the sudden increase in monkeypox cases stems from mutations that make it easier to spread the virus, and whether previous monkeypox outbreaks can be traced back to the same origin, McIntyre said.

will it become a pandemic

　　WHO data shows that exposure to damaged skin, respiratory secretions, droplets and contaminated items of monkeypox patients may be infected. The incubation period may be as long as 21 days. The highest risk of infection is after monkeypox patients develop symptoms. People with whom they have had close physical contact.

　　Many of the recent cases have been infected with gay, bisexual or other men who have sex with men.

Hunter said that while monkeypox "is generally a non-transmittable disease and may not pose much of a risk to the general population, it is certain that certain groups of people are at higher risk".

　　Will monkeypox be the next pandemic?

Hunter pointed out that "the fact is, early in the spread of any infectious disease, we don't know all the answers", but the monkeypox virus "will never be the new coronavirus."

　　Covid-19 is a rapidly evolving RNA virus with variants that often evade immunity from vaccination or earlier infection, McIntyre said.

And monkeypox is caused by a relatively large DNA virus, which is better at detecting and repairing mutations than RNA viruses, meaning monkeypox is unlikely to suddenly evolve into a virus that spreads easily from person to person.

　　WHO said there is an urgent need to raise awareness of monkeypox and implement comprehensive measures to detect and isolate cases, trace contacts, and provide supportive care to limit its further spread.

Hunt believes that the key to controlling monkeypox outbreaks is a "ring vaccination" strategy that "identifies every case as quickly as possible and then vaccinates all close contacts," which is also how humans eliminate smallpox.

He called on countries to strengthen cooperation "to control the monkeypox epidemic in the next month or two, because humans already have a very effective vaccine against monkeypox".