With cases reported in several countries, human monkeypox infection is generating global interest and concern as an emerging infectious disease threat, even amid the slowly relenting COVID-19 pandemic. Too.
What is monkeypox virus?
Monkeypox is a member of a closely related group of viruses in the Orthopoxvirus genus that includes smallpox, smallpox, and camelpox. Monkeypox virus was first discovered in the summer of 1958 at a research institute in Denmark as a non-fatal, smallpox-like, skin disease of captive monkeys.
The name monkeypox is a misnomer because terrestrial African rodents (mice and squirrels) serve as natural reservoirs of the virus, while monkeys and other primates are thought to be casual hosts.
When was monkeypox first recorded in humans?
The first known case of human monkeypox infection was reported in 1970 from the Democratic Republic of the Congo, in a nine-month-old baby with a non-fatal smallpox-like illness.
Since then, sporadic human cases have been reported in several Central and West African countries, with the infection being more common in children and young adults. In countries where monkeypox is endemic (where it is commonly found), the recent increase in cases is thought to be related to climate change, deforestation, war, increased population dynamics and decreased herd immunity from smallpox vaccination. goes.
How is monkeypox spread?
Transmission can occur through close physical contact with animals or humans, droplet particles contaminated with their body fluids, respiratory secretions or infected skin wounds, and indirectly by “fomites” (inanimate objects such as bed linens, towels and hard surfaces laden). is) through. infectious virus particles).
Animal bites and consumption of animal flesh are common modes of transmission in endemic areas. Secondary infection occurs among non-vaccinated close contacts in about 12.3 percent of household contacts and 3.3 percent of others.
When was monkeypox first recorded in non-African countries?
The first group of human monkeypox infections outside Africa occurred in the United States in 2003. A multi-state outbreak involving 87 children and young adults was attributed to close contact with infected prairie dogs obtained as pets from an animal distributor. The final source of infection was found to be imported Gambian rats that transmitted the infection to prairie dogs. No human deaths occurred, although three children experienced severe illness.
Prior to 2022, there were a number of travel-related cases in the United Kingdom, Israel, Singapore and the US among individuals who had visited Nigeria.
What do we know about global monkeypox outbreaks in non-endemic countries?
On May 7, 2022, a case of imported human monkeypox infection in a traveler returning from Nigeria was reported to public health authorities in the UK. Since then, there have been more than 550 confirmed cases of human infection 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 monkeypox infection are similar to smallpox, but are usually much milder. Unlike monkeypox, smallpox is an eradicable disease, has no animal reservoir and does not usually affect lymph nodes.
The incubation period of monkeypox 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, tender lymph nodes in the neck and groin.
The next stage involves a multi-stage rash that progresses from small patches of skin to papules (small bumps on the skin), followed by vesicles (small bumps filled with clear fluid) and then pustules (small bumps filled with pus). Huh. These are most prominent on the face, palms and soles of the feet. The blisters resolve by scarring or crusting over the next two to four weeks.
Exposed people may also have a sore throat, cough, and/or a rash on the mucous membranes of the mouth.
How serious is a monkeypox infection?
The disease is usually mild, although severe 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 percent for the West African variant and 10.6 percent for the Central African variant have been reported in endemic areas.
However, there have been no deaths to date with any of the cases reported outside Africa. All confirmed cases from the 2022 outbreak in 30 non-endemic countries have been caused by the West African variant.
Are there any other public health recommendations for monkeypox?
People infected with monkeypox should wear a surgical mask, and keep skin wounds covered until they heal. Items of personal use such as towels and sheets should not be shared. Frequently touched surfaces should be disinfected regularly, contaminated clothing should be washed and contact with household and non-household members should be avoided until the illness is cured.
Health care workers should use gloves, gowns and respiratory protection with N95 masks and face shields, and maintain excellent hand hygiene when caring for monkeypox patients. Hospitalized patients with confirmed or suspected monkeypox should be isolated with precautions for airborne, droplet and contact transmission until they are no longer contagious.
Does the smallpox vaccine protect against monkeypox?
The smallpox vaccine — given before or after exposure to monkeypox — can prevent or reduce the effects of human monkeypox infection. However, rare but serious adverse events have been reported from older generation smallpox vaccines. A new generation, non-replicating, live vaccine is now available and is considered safe for use in all populations, including those with compromised immune systems.
The US Centers for Disease Control and Prevention Advisory Committee on Immunization Practices, a new generation of vaccines for laboratory workers performing monkeypox diagnostic tests, as well as pre-exposure prophylaxis for health care workers administering smallpox prior to vaccination). Vaccine or care for patients with monkeypox. (Its trade name is Genios in the US, Imvamune in Canada, and Imvanex in Europe.)
In Canada and other developed countries, people born before 1972 were vaccinated against smallpox. Although immunity after vaccination decreases with age, lifelong immunity after smallpox vaccination in otherwise healthy individuals appears to be the norm, and its cross-protective efficacy against monkeypox is thought to be 85 percent.
Is monkeypox the next viral pandemic?
The emergence of infectious diseases such as monkeypox in non-endemic areas has created a great concern in light of our experience with COVID-19.
Monkeypox was 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 basic reproduction number (R0), a measure of viral infectivity, where R0 is equal to the number of secondary infections transmitted from a single case in a non-immune population, is 0.6 to 1.0 for the Central African variant, and for the West It is very little. African version.
In contrast, the R0 for the Omicron variant of SARS-CoV-2 is about 10, and the R0 for measles ranges from 11 to 18. The R0 for the West African type of monkeypox virus may be too low for humans to maintain. Human transmission outside endemic areas.