Yes, it’s true: CDC has confirmed a case of the rare tropical disease known as monkeypox in a Dallas, TX resident who recently returned from travel in Nigeria.
Here’s what you need to know about monkeypox.
First of all, unless you spend time in central or western Africa, you’re probably not going to get it. In fact, if you do spend time in those places, you’re probably not going to get it. It is not going to turn into a pandemic–it’s just not contagious enough.
Monkeypox in humans is rare, even in those areas where it is endemic. Endemic: that’s a word to describe a pathogen’s normal “range”–where it usually circulates, within a specific region and population.
Monkeypox rarely causes outbreaks even in monkeys, and it is quite unusual in humans. This is a relatively newly identified disease. It was identified in 1958 in colonies of monkeys who were kept in captivity for research. The first human case was recorded in 1970. It’s caused by a virus in the same genus as variola virus (the cause of smallpox), vaccinia virus (which is used in the smallpox vaccine and the etymological origin of the word vaccine), and cowpox virus.
Outside of certain parts of Africa, monkeypox is very rare. There was a medium sized outbreak in the United States in 2003, when 47 people were diagnosed. And there have been just a handful of other cases outside of its endemic region since then. The 2003 outbreak started when a shipment of infected animals was imported to the United States. All of the people infected in this outbreak had direct contact with infected, imported prairie dogs–of all things–purchased as pets. There were no instances of human-to-human transmission in this outbreak.
People who have monkeypox have symptoms similar to smallpox, but the symptoms are more mild. The incubation period–the time between when someone is exposed and when they start to show symptoms–is 7-14 days. Symptoms include fever, headache, muscle aches, back ache, chills, and fatigue. Within a few days, a rash develops involving bumpy red spots on the face which spreads to other body parts. These spots develop into blisters, which crust over and eventually heal. Illness lasts for 2-4 weeks. An infected person may be able to spread the disease to other people for the entire period of illness, until all the rash lesions have healed.
The virus is transmitted when someone comes into contact with viral material and it gets into their body through broken skin, respiratory tract, or eyes/nose/mouth mucous membranes. Human-to-human transmission is thought to be mostly through the respiratory route.
No one knows where monkeypox lives when it’s not infecting monkeys or people. There is some limited evidence suggesting a rodent may be the carrier.
There is no specific treatment for monkeypox and it can be serious or even fatal. The good news: there’s a vaccine. Because they are so closely related, the smallpox vaccine also prevents monkeypox.
But you’re probably not vaccinated for smallpox. Smallpox, which is a HORRIBLE human infectious disease, is the first and only eradication success story in history. Through 200 years of sustained effort and a massive global vaccination program, smallpox has been 100% eradicated from planet Earth. The last wild variola minor infection was recorded in Somalia in October of 1977. There were two cases in 1978 from a lab accident, and there have been zero cases since then. It’s really an amazing story, which I’ll tell on another day.
In the USA, routine smallpox vaccination ended in the 1970’s. Certain small populations who have high risk of occupational exposure to smallpox still get vaccinated, but most people do not. There are two vaccines approved by the FDA to prevent smallpox, and one of them (JYNNEOS, aka Imvamune or Imvanex) is also approved to prevent monkeypox. The Advisory Committee on Immunization Practices (ACIP) is currently evaluating JYNNEOS for protection of people at risk of occupational exposure to smallpox and monkeypox–such as people who work in monkey labs.
During the 2003 monkeypox outbreak, the CDC recommended that certain people be vaccinated, including people who were investigating cases, healthcare workers who were in close contact with monkeypox patients, household contacts of infected people, anyone who had exposure to an infected animal, and lab workers who handled monkeypox virus specimens during the outbreak.
Similarly, the CDC recently said that they are tracing close contacts of the patient in Dallas. Although the person with monkeypox traveled on two airplanes while they were ill, since everyone on the flights was required to wear masks anyway, they think it’s not likely that he gave it to anyone else on the plane. They may recommend a vaccine to anyone who has had close contact with this unfortunate person.