Magnified smallpox virus particles magnified and colored. Since the beginning of May, more than 550 confirmed cases of human infection with the monkeypox virus have been reported in 30 countries. Credit: NIAID
Since it spread outside of Africa and Europe and North America, the news has been filled with warnings about the monkeypox outbreak. In fact, according to the World Health Organization (WHO) as of June 2, 2022, cases of smallpox have been reported in 27 different non-endemic countries: United Kingdom, Spain, Portugal, Canada, United States , Netherlands, Italy, Germany, France, Argentina, Mexico, Morocco, UAE, Austria, Belgium, Czech Republic, Denmark, Finland, Hungary, Ireland, Israel, Malta, Norway, Slovenia, Sweden, Switzerland and Australia.
These Monkeypox FAQs will answer common questions such as:
- What is the smallpox of the monkey?
- Where did it come from?
- How is it transmitted?
- What are the symptoms?
- What are the public health recommendations?
- Does the smallpox vaccine offer protection?
- Is the next viral pandemic?
With cases reported in several countries, human smallpox infection is generating global interest and concern as a threat of emerging infectious disease, even amid a slowing COVID-19 pandemic.
What is the monkeypox virus?
Monkeypox is a member of a closely related group of viruses of the genus Orthopoxvirus that includes smallpox, smallpox, and smallpox. Monkeypox virus was first discovered in the summer of 1958 as a non-lethal, smallpox-like skin disease in captive monkeys at a research institute in Denmark.
The name monkeypox is an inappropriate name, as African terrestrial rodents (rats and squirrels) serve as a natural reservoir for the virus, while monkeys and other primates are believed to be accidental hosts.
The first human case of smallpox was recorded in 1970 in the Democratic Republic of the Congo (DRC) during a period of intense effort to eliminate smallpox. Credit: CDC
When was the smallpox first reported in humans?
The first known case of human smallpox infection was reported in the Democratic Republic of the Congo in 1970, in a nine-month-old boy with a non-fatal smallpox-like disease.
Since then, there have been sporadic human cases in many Central and West African countries, with more frequent infections in children and young adults. In countries where monkeypox is endemic (where it is commonly found), recent increases in cases are thought to be related to climate change, deforestation, war, increased population mobility, and declining population mobility. herd immunity from smallpox vaccination.
How is the monkey’s smallpox transmitted?
Transmission occurs through close physical contact with animals or humans, their body fluids, particulate matter contaminated with respiratory secretions, or infected skin lesions, and indirectly through “fomites” (inanimate objects such as sheets, towels, and hard surfaces that can be loaded with infectious viral particles).
Animal bites and the consumption of animal meat are common modes of transmission in endemic areas. Secondary infections among unvaccinated close contacts occur in about 12.3% of domestic contacts and 3.3% of others.
The first smallpox outbreak of monkeys in the United States occurred in 2003 when several people became infected after coming into contact with dogs from prairies that had the virus.
When was monkeypox first reported in non-African countries?
The first group of human smallpox infections outside of Africa occurred in the United States in 2003. A multistate outbreak was attributed to 87 children and young adults in close contact with infected prairie dogs acquired as pets. from an animal dealer. The main source of infection was found to be imported Gambian rats that transmitted the infection to prairie dogs. There were no deaths, although three children were seriously ill.
Prior to 2022, several cases involving travel to the UK, Israel, Singapore and the US had been reported among people who had visited Nigeria.
What do we know about the global outbreak of monkeypox in non-endemic countries?
On 7 May 2022, the UK public health authorities were informed of a case of human smallpox infection imported in a traveler returning from Nigeria. Since then, more than 550 confirmed cases of human infection have been reported in the UK and 29 other countries. Cases have been much higher among men who have sex with men, although the virus is not known to be sexually transmitted.
What are the symptoms of monkeypox?
The clinical manifestations of human smallpox infection mimic those of smallpox, but are usually much milder. Unlike monkeypox, smallpox is an eradicated disease, has no animal reservoir and does not usually affect the lymph nodes.
The incubation period for smallpox in humans ranges from four to 21 days and is followed by a one- to five-day phase of fever, chills, sweating, fatigue, and enlarged and tender lymph nodes. neck and groin.
The next stage involves a multi-stage rash that progresses from small skin spots to papules (small bumps on the skin), followed by vesicles (small bumps filled with clear fluid) and then pustules (small bumps full of pus). These are most prominent on the face, palms and soles of the feet. Pustules resolve by scars or scabs within the next two to four weeks.
Exposed people may also develop sore throat, cough and / or rash on the mucous membranes of the mouth.
How serious is the monkeypox infection?
The disease is usually mild, although serious illness and death can occur. There are two common genetic variants of the monkeypox virus: the Central African variant and the West African variant. Mortality rates of 3.6 per cent for the West African variant and 10.6 per cent for the Central African variant in endemic regions have been reported.
However, so far no deaths have been reported in any of the reported cases outside Africa. All confirmed cases of the 2022 outbreak in 30 non-endemic countries have been due to the West African variant.
Colorful and enlarged monkeypox virus particles. Credit: NIAID
Are there any other public health recommendations for monkeypox?
People infected with monkeypox should wear surgical masks and skin lesions should be covered until they have healed. Personal items such as towels and sheets should not be shared. Frequently touched surfaces should be periodically disinfected, contaminated clothing should be washed, and contact with household and non-household members should be avoided until the disease has resolved. .
Healthcare workers should wear gloves, gowns, and respiratory protection with N95 masks and face shields, and maintain excellent hand hygiene while caring for monkeypox patients. Patients hospitalized with confirmed or suspected smallpox should be isolated with precautions for airborne, drip, and contact transmission until they are no longer contagious.
Does the smallpox vaccine protect against smallpox?
The smallpox vaccine, given before or after exposure to smallpox, can prevent or reduce the effects of human smallpox infection. However, rare but serious adverse events have been reported in older generations of smallpox vaccines. A new generation live vaccine is now available, which is not replicated and is considered safe for use in all populations, including those with compromised immune systems.
The U.S. Centers for Disease Control and Prevention’s Immunization Practice Advisory Committee recommends pre-exposure prophylaxis (vaccination prior to exposure to the virus) with the next-generation vaccine for laboratory workers who carry out diagnostic tests for smallpox, as well as for health workers who administer the smallpox vaccine or treat patients with monkeypox. (Its trade name is Jynneos in the US, Imvamune in Canada and Imvanex in Europe.)
In Canada and other developed countries, people born before 1972 were probably vaccinated against smallpox. Although post-vaccination immunity tends to decrease with age, lifelong immunity appears to be the norm after smallpox vaccination in otherwise healthy individuals, and it is believed that their Cross-protective efficacy against monkeypox is 85 percent.
Is monkeypox the next viral pandemic?
The emergence of infectious diseases such as monkeypox in non-endemic areas has created great anxiety in light of our experience with COVID-19.
Smallpox had been a neglected tropical disease until the current outbreak in the developed world. But the trajectory of these cases, along with the pattern of transmission in Africa, suggests that the virus will not become a pandemic.
The baseline number of reproduction (R0), a measure of viral contagion, where R0 is equal to the number of secondary infections transmitted in a single case in a non-immune population, is 0.6 to 1.0 for variant of Central Africa and much lower to the west. African variant.
In contrast, the R0 for the Omicron variant of SARS-CoV-2 is approximately 10, and the R0 for measles ranges from 11 to 18. The R0 for the West African variant of the virus of monkeypox may be too low to keep man a- human transmission out of endemic areas.
Written by Sameer Elsayed, Professor of Medicine, Pathology and Laboratory Medicine, and Epidemiology and Biostatistics, Western University.
This article was first published in The Conversation.