Episode 104: What is Monkeypox.
Monkeypox is a rare disease caused by the monkeypox virus that belongs to the orthopoxvirus (smallpox) family. Nabhan, Dr. Schlaerth, and Dr. Arreaza discuss the basics of what is known about this disease.
Introduction: Monkeypox
By Hector Arreaza, MD.
As of June 29, 2022, there are 5,115 confirmed cases of monkeypox in the world. The country with the most cases is the United Kingdom with >1,000 cases. In the United States, there are 351 confirmed cases, distributed in 28 states, and the state with the highest number of cases is California with 80 cases. Today we will briefly discuss the history, epidemiology, transmission, and management of monkeypox. By the way, by the time you listen to this episode, this disease may have a different name, as the World Health Organization is planning to rename it to minimize stigma and racism.
Monkeypox is still rare, but because of the current outbreak, we need to include it in our list of differentials when we see rashes. Symptoms of monkeypox can include fever, chills, headache, myalgias, lymphadenopathies, and general malaise. The rash resembles pimples or blisters that appear on the face, inside the mouth, and on other parts of the body, like the hands, feet, chest, genitals, or anus. The rash goes through different stages before healing completely. The illness typically lasts 2-4 weeks. Monkeypox spreads by direct or indirect contact with rash, respiratory secretions, and vertical transmission from mother to fetus. Sometimes, people get a rash first, followed by other symptoms. Others only experience a rash. Currently, there is not a formal treatment for the disease. The information will continue to evolve in the future.
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This podcast was created for educational purposes only. Visit your primary care provider for additional medical advice.
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What is monkeypox.
By Nabhan Kamal, MS3, American University of the Caribbean School of Medicine. Comments by Katherine Schlaerth. Moderated by Hector Arreaza, MD.
Background.
Monkeypox is a viral zoonotic infection that results in a rash similar to smallpox. It is estimated that humans have been infected by the monkeypox virus for centuries in sub-Saharan Africa. Monkeypox is an orthopoxvirus that was first isolated in the decade of 1950s from a colony of sick monkeys. The variola virus and the vaccinia virus are in the same genus as the monkeypox virus. Variola is the smallpox virus, and vaccinia is the virus in the smallpox vaccine. The virion that has been seen in cells infected with the monkeypox virus looks exactly the same as the virions of variola or vaccinia viruses. It has a characteristic brick-like appearance.
The two strains of monkeypox identified in different regions of Africa are Central Africa and Western Africa. It seems like the strain of Western Africa is less virulent and lacks a number of genes present in the Central African strain.
Transition to talking about Epidemiology
Why is understanding the epidemiology of monkeypox important? I think it’s important to touch on the epidemiology of the virus because it will help healthcare providers better understand the disease and have a more productive discussion with their patients about this illness if they, unfortunately, happen to fall victim to it.
Epidemiology
In the 70s, the first time monkeypox was identified as a cause of disease in humans. It happened in the Democratic Republic of the Congo (formerly the Republic of Zaire). After that, only 59 cases of human monkeypox were identified in the decade between 1970 and 1980, with a mortality rate of 17%. All of these cases occurred in the rain forests of Western and Central Africa. These cases occurred in people exposed to rodents, squirrels, and monkeys. An important fact to note is that despite the virus being called “monkeypox”, monkeys and humans are incidental hosts; the reservoir remains unknown but is likely to be rodents. Despite the current common belief that this is the first outbreak of monkeypox in the US, the actual first outbreak of monkeypox in the Western Hemisphere occurred in the United States in 2003.
Transition to talking about Transmission
Is the monkeypox virus extremely virulent and transmissible just like SARS COV-2? All people born after 1972 have not been vaccinated against smallpox. Routine vaccination of the American public against smallpox stopped in 1972 after smallpox was eradicated in the United States. The virus can spread between animals and humans, just like COVID-19 is believed to be.
Transmission
Animal-to-human transmission – A person gets infected by monkeypox by contact with body fluids coming from an infected animal or through a bite. Monkeypox infection has been found in many types of animals in Africa, including rope squirrels, tree squirrels, Gambian poached rats, dormice, and different species of monkeys.
Human-to-human transmission – In general, humans get infected from other humans through large respiratory droplets, which are produced during cough or sneezing. Also, a person can get infected by close contact with infectious skin lesions and particles or from sexual contact with skin lesions.
Currently, transmission from person-to-person is very low. An outbreak of monkeypox was reported in May 2022 in non-endemic countries with over 90 confirmed cases. Non-endemic countries are all countries outside of Central and Western Africa. However, in this new outbreak, it appears that close contact with infectious skin lesions during sexual contact may be the most likely mode of transmission based on the majority of initial cases in Europe being recorded amongst men who have sex with men.
As of this recording on June 8, 2022, there are a total of 1088 cases in 29 countries. The UK leads the world with 302 confirmed cases while the US only has 34 confirmed cases.
Incubation period
The classic incubation period of monkeypox virus infection is usually from 6 to 13 days but can range from 5 to 21 days. Important to note, however, is that persons with a history of an animal bite or scratch may have a shorter incubation period than those with tactile exposures (9 versus 13 days, respectively). So, the infection shows up earlier in people who get an animal bite or scratch.
Management
Most patients with monkeypox will have mild disease and recover without medical intervention. For patients who are symptomatic, most of them will not require hospitalization. Unlike chickenpox, the vesicular rash caused by monkeypox occurs all at once rather than new lesions appearing as old ones start to crust over and heal.
Antivirals: In some rare cases, antiviral medications can be used for patients that become severely ill as a result of being immunocompromised from HIV, various cancers, organ transplant recipients, etc. The antiviral drug of choice is Tecovirimat. It’s a potent inhibitor of an orthopoxvirus protein required for dissemination within an infected host. This medication protects nonhuman primates from lethal monkeypox virus infections and is also likely to be efficacious against infection in humans. It’s interesting that these medications have been approved for smallpox treatment.
In patients that have severe disease, dual therapy with Tecovirimat and Cidofovir is recommended. It has in vitro activity against monkeypox and has been shown to be effective against lethal monkeypox in animal models. However, there isn’t any clinical data regarding Cidofovir’s efficacy against monkeypox infection in humans specifically, and it also has significant side effects including nephrotoxicity.
In June 2021, brincidofovir was approved for use in the US for the treatment of smallpox. Brincidofovir is an analog of cidofovir (meaning that it is almost the same with some small tweaks) that can be given orally. Given how new it is, however, its clinical availability is uncertain at this time.
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Conclusion: Now we conclude our episode number 104 “What is Monkeypox.” Monkeypox is a developing story and we have presented information that may become obsolete in the future. For now, remember to rule out monkeypox in your patients who are highly suspicious to have it, for example, patients with STI-related rashes or with a viral illness followed by a papular rash. Even without trying, every night you go to bed being a little wiser.
This week we thank Hector Arreaza, Katherine Schlaerth, Nabhan Kamal, and Lillian Petersen.
Thanks for listening to Rio Bravo qWeek Podcast. If you have any feedback, contact us by email at RioBravoqWeek@clinicasierravista.org, or visit our website riobravofmrp.org/qweek. Audio edition: Suraj Amrutia. See you next week!
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References:
- Centers for Disease Control and Prevention, CDC.gov, https://www.cdc.gov/poxvirus/monkeypox/, accessed on June 30, 2022.
- Muller, Madison, WHO Will Rename Monkeypox Virus to Minimize Stigma and Racism, TIME, June 14, 2022.
- Isaacs, Stuart, MD, Monkeypox, UpToDate, https://www.uptodate.com/contents/monkeypox, accessed on Jun 06, 2022.
