"Monkeypox" has been reported one after another mainly in Europe and the United States.
It is an infectious disease that causes symptoms such as a rash that is similar to smallpox, and more than 1000 people have been confirmed to have the infection in Europe and the United States.
What kind of illness is monkeypox and how should we deal with it?
We have summarized what we know so far, such as the situation and response of each country and the views of experts (as of June 13, 2022).
(Naoki Azuchi, Faculty of Science and Culture / Tetsutaro Soe, General Bureau of the United States)
Unusual spread in Western countries
"The risk of monkeypox becoming established in countries that were not previously endemic has become a reality,"
WHO = World Health Organization Secretary-General Tedros expressed a sense of crisis at a meeting on June 8, 2022. ..
Monkeypox was originally reported in some African countries, but has spread to Western countries since May 2022.
In Europe, cases of monkeypox were first reported in the United Kingdom in early May, and cases were confirmed one after another in Spain and Portugal.
Patients were also identified in Canada and the United States at the same time.
The number of confirmed cases has increased, and as of June 8, more than 1,200 cases have been confirmed in 28 countries other than the areas where monkeypox was established.
As a result of genetic analysis of the virus, it is said that the virus of the West African strain, which is relatively low in pathogenicity, is spreading, and no one died.
"Monkeypox" with a characteristic rash In some cases, it becomes severe
"Monkeypox" is a disease caused by infection with "monkeypox virus", which is similar to smallpox virus.
According to websites such as the National Institute of Infectious Diseases and WHO, the incubation period of monkeypox virus is usually 7 to 14 days, and after the incubation period, fever, headache, lymphadenopathy, myalgia, etc. start from 1 day. It lasts for 5 days, after which a rash appears.
The rash typically begins on the face and spreads throughout the body.
It gradually swells and becomes blisters (blisters), scabs, scabs, and heals within 2 to 4 weeks after the onset.
In most cases, it is mild and recovers spontaneously, but it can cause complications such as pneumonia and sepsis, and it is said that the younger you are, the more severe it may be.
Why is it called "monkeypox"?
It was first discovered in 1958 in cynomolgus monkeys at a facility where primates were gathered from around the world to produce polio vaccines.
However, the natural host carrying this virus under normal conditions is thought to be a reservoir, not a monkey.
Human transmission was first identified in the Republic of the Congo in 1970, and has since spread sporadically in the rainforest regions of Central and West Africa.
In 2003, the virus was introduced into the United States through small animals imported as pets from Africa, infecting 71 people.
Monkeypox infections are still frequent in Africa, and according to WHO, since January 2022, the number of infected people including suspected cases has risen to 1536 in eight countries including the Democratic Republic of the Congo and Nigeria, 72. A person is dead.
In addition, it is said that different strains of virus are spreading in West Africa such as Nigeria and Central Africa such as the Democratic Republic of the Congo.
Monkeypox found in Central Africa is more likely to become more severe, with case fatality rates ranging from a few percent to 10%.
In recent years, all cases confirmed outside Africa have a pattern of onset of returnees from Nigeria, and several cases have been confirmed annually.
No one has died outside of Africa.
What is the infection route?
Monkeypox is generally said to be transmitted by being bitten by infected animals such as mice and squirrels, or by touching blood, body fluids, or rashes.
It has also been pointed out that anyone can be infected by contact with the infected person's rash, body fluids, scabs, bedding or clothing used by the patient, or by being exposed to flying shots at a short distance. increase.
Regarding the spread of the infection, WHO and the ECDC = European Centers for Disease Control and Prevention have stated that anyone can be infected by close contact, and many of the patients confirmed in the follow-up survey so far. Alleges that there was sexual contact between men.
Some experts have suggested that the infection may have spread through large-scale events held across Europe, and countries are wary of more such events in the coming summer. I'm calling.
On the other hand, patients who are considered to be so-called "community-acquired infections" whose infection route cannot be identified and female patients have been confirmed, and it is necessary to be cautious without considering it as a disease of a specific group of people.
The WHO states that anyone who has had close contact with a person with monkeypox is at risk of getting infected, "no one should be unfairly treated because of the disease."
WHO encourages people with symptoms to be tested, avoid close contact with others, and seek medical attention.
What is worrisome now is that monkeypox will take root in Europe, where it has never been seen before.
WHO is calling on countries to strengthen patient tracking and quarantine to stop colonization, but the chain of infections has not been stopped in the United Kingdom and Spain.
The ECDC says it is "very unlikely" and points out that if human-to-human transmission continues, it may eventually infect animals and become established in Europe.
Highly effective for smallpox vaccine
The once inoculated smallpox vaccine is highly effective against monkeypox, and according to WHO, the effect of preventing monkeypox infection is up to 85%.
However, smallpox was eradicated from the earth in 1980 as a result of active vaccination.
The last vaccination in Japan was in 1976, and the current generation of children in their late 40s and above has been vaccinated and may be immune to monkeypox.
There are vaccines for smallpox in Japan that are said to be highly effective and have few side reactions, and are stockpiled nationally as part of counterterrorism measures.
Although the development of drugs for monkeypox is underway, there is no treatment like a silver bullet so far, and each country is responding with symptomatic treatment.
Vaccination movements in Europe and the United States
In Western countries, there are a series of movements to purchase new vaccines for smallpox as a countermeasure against monkeypox infection.
In some countries, such as Canada, vaccinations have begun on healthcare workers and those who have come into contact with patients.
However, it is becoming an issue that few people want to be vaccinated even if they are in contact with patients.
In a report released by the British health authorities on June 2, 69% of health care workers who were asked to get vaccinated wanted to get vaccinated, compared to only 14% of those who came into contact with the patient. It is said that he did not wish to be vaccinated.
"In order to achieve the goal of eradication, rapid detection of patients and tracking of transmission routes are essential. We should also consider measures other than vaccines, such as regular tests."
No report in Japan
According to the Ministry of Health, Labor and Welfare, no monkeypox infections have been reported in Japan since 2003, when the data was started.
Monkeypox is designated as "Class 4 infectious disease", which is the same as rabies under the Infectious Diseases Control Law, and the doctor who diagnosed it must report the outbreak to the health center.
The Ministry of Health, Labor and Welfare will contact prefectures on May 20th and June 1st to report any suspicious patients and request that they be hospitalized at designated medical institutions.
In addition, monkeypox can be tested by PCR from the liquid contained in the blisters in the same way as the new coronavirus, but at the moment, only the National Institute of Infectious Diseases can make a definitive diagnosis.
From now on?
What is the preventive method?
We spoke with Professor Shigeru Morikawa of Okayama University of Science, a former director of the Department of Veterinary Sciences at the National Institute of Infectious Diseases, who has been studying "monkeypox" about the current infection status and future countermeasures.
Q. How do you evaluate the current infection status?
I don't think the number of patients will increase so rapidly, and I don't think WHO expected it.
It is spreading at a pace where one infected person infects four people.
It's a strange situation because people told me that it wouldn't move so much.
Q. What is behind the spread of the infection?
It has been pointed out that the infection has spread to families living with patients.
I think that the infection has been established by touching the rash or the affected area, or touching the shirt or bedding worn by the patient.
Q. Is the infectivity stronger than before?
It seems that neither WHO nor CDC think that it has stronger infectivity than before.
The situation is that the infection has spread through close contact and has spread to people who live in the same house as the patient.
I don't think it's spreading more and more due to flying infections or airborne infections.
Also, with smallpox, symptoms like influenza such as fever and chills first appear, and a rash appears several days later, but with this monkeypox, there is no fever or chills and a rash suddenly appears even though it was fine. Many patients have been reported.
It is possible that the infection has spread without your knowledge.
Some experts point out that neither the patient nor the doctor who examined the patient noticed monkeypox, and the infection spread little by little and spread all at once in a large rally.
Q. Is it possible that the virus has been mutated to increase its infectivity?
It is possible, but no gene mutation has been found that fits that hypothesis.
In addition, monkeypox virus is a type of "poxvirus", which has a long DNA sequence and has the property that mutations cannot be easily entered.
Q. Is there a possibility that it will flow into Japan?
Since there are more than 1000 infected people in about 30 countries, there is a natural risk that infected people during the incubation period will enter Japan and develop the disease.
It is possible that the acceptance of tourists from overseas will resume, and infected people will come from overseas and develop the disease.
Q. What kind of measures should I prepare for?
If an infected person appears in Japan, it will be necessary to carry out an examination including those with close contact.
Currently, it can only be tested at the National Institute of Infectious Diseases, but I think that preparations are underway so that it can be tested at the local health laboratories in each local government.
At medical institutions, I think that monkeypox should be suspected for people who have fever or rash from overseas.
Q. Are there any points that people who go abroad such as Europe should be careful about?
There is almost no risk of infection by discussing, talking, and eating with business partners.
However, I sometimes hug or kiss when greeting, but I think it is better to avoid such contact.
Q. How vigilant should I be?
I don't think you need to worry too much for now, but there are some parts that I don't know what will happen in the future.
However, I do not think there is a risk of community-acquired infection at this time.
As the number of people coming from overseas increases, the risk of inflow should increase, so it is important to first take measures at the water's edge, and if there are people with fever or rash, find them in the airport quarantine and connect them to the inspection.
People who do not know on the spot and then have symptoms need to see a medical institution for appropriate tests and treatment.