On May 18th, 2022, Massachusetts health officials announced that they confirmed a case of monkeypox. This was the first case of this rare and, in some cases, fatal viral infection. Although stories of monkeypox infections in the United States are usually brushed off as an anomaly, this news comes amid a few clusters of infections appearing outside the area where the disease is usually found. A day before the case in the U.S., the Centers of Disease Control and Prevention (CDC) had expressed concern about an unusual outbreak of the infection in the United Kingdom, where the first outbreak was spotted (Source: Washington Post)

Maria Van Kerkhove, who leads the emerging diseases and zoonoses unit in the World Health Organization’s Health (WHO) Emergencies Program, said that there had been confirmed cases in a few other European countries. “We have had positive cases identified in the U.L., Portugal, and Spain. And we expect there will be others,” said Van Kerkhove (Source: Stat News).

Earlier that day, Spain had announced that they were investigating eight suspected cases of monkeypox, Portugal said they were investigating more than 20 suspected cases, five of which have already been confirmed and the U.K. have confirmed nine confirmed and one probable cases were officially reported. At the time of this article, a clear link has not been established linking the outbreaks to each other. “There could be dynamic transmission here that we just haven’t appreciated because of the potential number of contacts,”said Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy. Osterholm emphasized the importance of collecting information documenting the intimacy contact patients have had and the possible locations of those contacts (Source: Stat News).

The possibility of another pandemic brings up concern of the repetition in the trend where middle- and low- income countries suffer the worst effects of the virus. This was observed with COVID, and it will likely be seen with future pandemics. That is why investment in public health measures are important, as they further global equity. However, it does not seem that we have learned much from COVID, and if rapid vaccination teams are deployed, underdeveloped countries may struggle to vaccinate their population. Also, middle- and low- income countries are known to have a younger population, which means that they are more susceptible to the virus, since smallpox vaccination prevents monkeypox (see below), but smallpox vaccinations were stopped in 1980s. Monkeypox is has higher fatality rate in younger populations, especially ones with co-morbidities, so it is an area of great concern for children in low- and middle- income countries.

The WHO has previously designated monkeypox as a priority pathogen and is scheduling a meeting of experts on monkeypox and orthopoxviruses- the wider family of pox viruses- for early this week. One of the main topics discussed will likely be the apparent alteration in the epidemiology of the virus in countries where it has been endemic for several years. “We’re seeing a shift in the age distribution of cases. We’re seeing a shift in the geographic distribution of cases,” said Michael Ryan, executive director of the WHO’s Health Emergencies Program. “We have to really understand that deep ecology. We have to really understand human behavior in those regions, and we have to try to prevent the disease from reaching humans in the first place” (Source: Stat News).

According to WHO, monkeypox is a viral zoonosis (basically a virus transmitted from animals to humans) and manifests in symptoms very similar to the ones seen in smallpox, although it has been seen as clinically less severe. Due to the eradication of smallpox in 1980, smallpox vaccinations were halted, while monkeypox has emerged “as the most important orthopoxvirus for public health.” Monkeypox is generally found in Central and West Africa and is usually detected in areas in close proximity to tropical rainforest but has increasingly appeared in urban areas. A number of animal species have been identified as susceptible to the monkeypox virus. This includes Gambian pouched rats, dormice, rope squirrels, tree squirrels and non-human primates. Studies are still needed to identify the exact reservoirs of the virus and how the virus’s circulation is maintained in nature (Source: WHO).

The first case of human monkeypox was identified in 1970 in the Democratic Republic of the Congo (DRC) in a child residing in a region where smallpox had been eliminated in 1968. Since then, most cases have been identified in rural, rainforest regions of the Congo Basin, and human cases have been increasingly reported across Central and West Africa. Since that first case, human cases have been reported in 11 African countries. “The true burden of monkeypox is not known,” states the website. Since 2017, Nigeria has been tackling a large outbreak of over 500 suspected and over 200 confirmed cases, with a case fatality ratio of approximately 3%. In 2003, the first monkeypox outbreak detected outside of Africa was detected in the U.S. and was linked to infected pet prairie dogs. The outbreak led to over 70 cases of monkeypox in the country (Source: WHO).

Animal-to-human transmission, also known as zoonotic transmission, can occur from direct contact with blood, bodily fluids, or cutaneous or mucosal lesions of animals infected with the disease, according to WHO. Eating inadequately cooked meat and other animal products of infected animals was also listed as a possible factor of transmission. More importantly in the recent outbreaks, human-to-human transmission has long been known to occur from close contact with respiratory secretions (aerosols), skin lesions of an infected person or recently contaminated objects. Health workers are at particular risk because transmission via droplet respiratory particles requires prolonged face-to-face contact. The longest chain of transmission has, in recent years, risen from six to nine successive human-to-human infections. “This may reflect declining immunity in all communities due to cessation of smallpox vaccination,” states the website. Transmission can also occur via placenta from mother to fetus, leading to congenital monkeypox, or close contact during and after birth. It is still unclear whether monkeypox can be spread via sexual contact (Source: WHO).

The incubation period, or the time between infection and the first onset of symptoms, of monkeypox is typically from 6 to 13 days but sometimes may range from 5 to 21 days, according to WHO. The infection period can be divided into two periods. The first is called the invasion period, which lasts from 0-5 days, and is characterized by usual cold symptoms, such as “fever, intense headaches, lymphadenopathy (swelling of lymph nodes), back pain, myalgia (muscle aches) and intense asthenia (lack of energy).” Lymphadenopathy is the distinctive symptom of the disease when compared to other similar diseases, such as chickenpox. The second period is characterized with skin eruption, which typically begins within 1-3 days of the appearance of fever. The rash tends to be concentrated in the face and extremities, specifically the hands and soles of the feet. The rash may also be found in oral mucous membranes in 70% of the cases, and less likely near the genitalia, conjunctivae and cornea. The rash evolves from lesions with a flat base to slightly raised firm lesions, lesions field with clear fluid, lesions filled with yellow fluid and crusts that tend to dry and fall off. The number of lesions may vary from just a few to several thousand and, in extreme cases, lesions have been observed to coalesce until large sections of skin “slough off” (Source: WHO).

Monkeypox has been seen as a self-limited disease with symptoms that last from 2-4 weeks. Severe cases are more likely to be observed in children and depend on factors, such as extent of viral exposure, the patient’s general health, and the nature of complications accompanying the infection. Underlying immune deficiencies have also been found as a factor for worse than usual health outcomes from an infection. Complications of monkeypox may also include secondary infections, such as “bronchopneumonia, sepsis, encephalitis, and infection of the cornea with ensuing loss of vision. The extent to which asymptomatic infection may occur is unknown,” according to WHO. The case-fatality of monkeypox has ranged from 0 to 11% in the general population historically and has been observed to be higher in younger populations. In recent times, however, the case fatality has hovered between 3-6% (Source: WHO).

Fortunately, a vaccine is already available. Vaccinia vaccine was manufactured to prevent smallpox but can also be used to protect against an infection of monkeypox. However, due to the cessation of smallpox vaccinations in 1980, the generation born after that great public health milestone are vulnerable to the disease. “Vaccination may need to be revived if the monkeypox continues to spread,” writes Carol Turkington and Bonnie Lee Ashby, wrote in “The Encyclopedia of Infectious Diseases” in 2003. Hopefully, the lessons from our battles with COVID may shine a light on our fights with future emerging infectious diseases, such as the medical mystery now in our hands (Turkington and Ashby, 2003).

Sources:

17, H. B. M., Branswell, H., Writer, A. the A. R. H. B. S., & Writer, H. B. S. (2022, May 19). CDC expresses concern about possibility of undetected monkeypox spread in U.K. STAT. Retrieved June 19, 2022, from https://www.statnews.com/2022/05/17/cdc-expresses-concern-about-possibility-of-undetected-monkeypox-spread-in-u-k/

18, H. B. M., Branswell, H., Writer, A. the A. R. H. B. S., & Writer, H. B. S. (2022, May 23). U.S. monkeypox case reported, as Spain, Portugal report infections in growing outbreak. STAT. Retrieved June 19, 2022, from https://www.statnews.com/2022/05/18/spain-portugal-report-monkeypox-cases-raising-specter-of-wider-outbreak/

Kornfield, M., Knowles, H., Bella, T., Bever, L., & Nirappil, F. (2022, June 16). What is Monkeypox, the rare virus now confirmed in the U.S. and Europe? The Washington Post. Retrieved June 19, 2022, from https://www.washingtonpost.com/health/2022/05/18/monkeypox-faq/

World Health Organization. (n.d.). Monkeypox. World Health Organization. Retrieved June 19, 2022, from https://www.who.int/news-room/fact-sheets/detail/monkeypox

Turkington, Carol, and Bonnie Lee Ashby. The Encyclopedia of Infectious Diseases. Second ed., Facts on File, Inc., 2003.