Monkeypox: An emerging menace!

Monkeypox lesions, image via Trends in Microbiology

Here’s something I wasn’t worried about before today: apparently there have been outbreaks of monkeypox over the past decade, and they are potentially spreading in number and range. This is via a review article in the February issue of Trends in Microbiology (note you must be on campus to download this link). So far outbreaks have been relatively limited to the Democratic Republic of the Congo (DRC), however epidemiologists are examining whether cessation of smallpox vaccination in the 1970’s, and current loss of protection to smallpox in populations might be leading the emergence of monkeypox infections in humans.

This discussion rekindles the ongoing debate as to whether stocks of variola (smallpox) virus should be destroyed. Arguments can be put forward supporting either stance; many view the potential risk of bioterrorism outweighing any possible medical benefit, whereas I argued in the above linked essay that we cannot predict future research needs that might be facilitated by having variola virus in the laboratory. This position seems to be borne out if the link between monkeypox and smallpox is valid.

The epidemiology of infection by smallpox and monkeypox are not the same. Although both viruses are related members of the orthovirus family, smallpox is exclusively a pathogen of Homo sapiens, a fact that greatly facilitated the eradication effort during the mid-20th century. Viable smallpox virus is no longer found anywhere in the wild, and currently exists only in freezers in the United States and Russia. Monkeypox on the other hand is a zoonotic disease, mainly found in non-human primate populations, and in the past has only very occasionally jumped the species barrier to infect humans. Unlike smallpox, monkeypox historically has had a very low mortality rate, and traditionally has not posed a significant health risk.

Current epidemiologic analysis suggests that the rate of infection has jumped approximately 10-fold in regions where the disease has been considered endemic. Furthermore, the highest rates of infection are found in individuals younger than 15 years of age, with increasing trends in the 15 to 30 year old cohort, all groups that were never vaccinated against smallpox or were too young to have ever had smallpox. This phenomenon argues for the possibility that smallpox offered protection against other orthovirus infections, which are now emergent in populations that have no protection against smallpox.

An interesting conundrum comes out from this scenario however; monkeypox has a broader distribution than just the Congo Basin, and increasing infection rates appear to be limited to that specific geographic region at present. Research into the pathogenesis of specific virus isolates, and mechanisms as to how the virus modulates the immune system may shed light into these geographical differences, and on the infection process of orthovirus infection and recovery. The review article concludes with the consideration that not only environmental and social concerns (climate change, human habitat modification, sociologic factors), but also the expansion of potential ecological niches in human hosts via changes in vaccination programs is altering host-pathogen balances, and may lead to further outbreaks of other infections.


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on February 11, 2012, in Danger danger danger!, Microbes in the News and tagged , . Bookmark the permalink. 6 Comments.

  1. I find this very interesting. I am a very big advocate for vaccinating children, because I feel the good almost always outweighs the risk. However, we now live in a day and age where parents are not having their children vaccinated because they are only focused on the bad stories we hear, of course because good news rarely gets any press, blaming vaccinations for all sorts of problems certain children developed including Autism. These same parents do not consider the risk they are putting other children and people in let alone their own children by not protecting them against these diseases. I think more problems like monkeypox, which never used to be human concern is going to continue to grow. As parents continue not to protect their children through vaccinations we are going to continue to see strange diseases attacking people, as the article said these people had not been inocculated against small pox and the CDC recommends Health Care workers who may be potentially exposed to monkeypox to get the vaccination. We have no idea what else is out there that our vaccinations are protecting us against and unfortunately I think monkeypox may only be the beginning.

    • I also am a big advocate of vaccination, and have had a number of postings in this forum indicating this. Check out this one for a particularly amusing rant. The emergence of monkeypox nicely demonstrates that the relationship between pathogens and hosts (us) is incredibly complex. Monkeypox may be emerging in human populations because we no longer has positive immune status to another, related virus. At first glance, one might think that it’s no big deal, as the complication rate from monkeypox is incredibly low relative to smallpox, however it does appear from this limited epidemiological study that there are different varieties of the virus, resulting in a complex distribution of human disease. I think a lot of infectious disease is like the carnival game “Whack a mole,” where we may be successful in eliminating one threat, and another one can pop up as a result.

  2. The monkey pox article is interesting and I noticed some student input on the significance of vaccinations. I am not an advocate on vaccinations unless emergent of the threat is posed as it is in the Congo Basin with the monkeypox. My opposition to vaccinations is mainly due to some of the preservatives used such as mercury and a host of side effects that come as a result of children being vaccinated. Quite a few of these articles do not make the news paper unfortunatey. My good friend, Dr. Joseph exposes many side effects that could potentially hurt children getting small pox vaccinations. (http// It appears in the article, those who were vaccinated for small pox did not contract the infection. Since the infection is specific to that area moreso than others researchers should also look at nutrition (diet for immunity defense). What are they eating, what have they been exposed to lately that is new to their environment, what has changed if anything topographically? I noticed environmental factors are being considered which is a boon for this small research conducted thus far. Due to the breakout, perhaps a quick fix such as the small pox vaccine may be the only hope.I can only hope in the future vaccines are made safer before they give them to anyone.

    • Thanks Ken, I suspect we will have to agree to disagree about the safety of vaccines. I firmly feel that the evidence supports the advocacy of many childhood vaccinations, and that the safety issues, based on the number of complications demonstrated using epidemiological methods, are far outweighed by the positive benefits to society. Take chickenpox for example (which I ranted about last semester): we generally think of chickenpox as an innocuous disease, so why get a shot to prevent it? It is relatively innocuous, but when millions of people get it annually, and this was the case when you and I were kids, thousands of people died from it, with fatal complications occurring on the order of 1 in 10,000 cases (see the chickenpox rant for a link to the Centers for Disease Control for a complication citation taken from local Departments of Health across the United States.) Conversely, there have been 48 million doses of varicella vaccine given out since 1995, with only 1000 adverse reactions which may include developing hives. A significant number of those vaccine “adverse reactions” also fail to be supported when causality is examined.That gives us a safety rating far in excess of 99.99%, and far fewer deaths due to chickenpox.

      • I am with you Dr. S…from a nurses stand point and also just someone who is an advocate of vaccination. I can not understand why parents would not want to take advantage of everything out there to protect their children. What I found interesting and don’t think I am mean but deserving is when I was on clinical at an elementary school I inquired about the children whose parents refuse to get them vaccinated; as I said I am very passionate about this subject. I was informed that if there is an outbreak of chicken pox, all of the children not vaccinated are not allowed to come to school, and in turn their parents can be fined depending on how much school the children missed. This made me smile inside, because as I said why put not only your children but the other children around them in unneeded risk.

        I found the GBS article interesting as well, mainly because when I was administering flu shots that was one of the questions I had to ask the receiver and it never made sense why. I figured one person coincidently got GBS after the flu vaccine and so therefore it must have been the cause; which is not a well constructed argument in fact it is illogical.

  3. It might be of interest that in the current influenza season that the UPenn medical center in Philadelphia requires ALL health care workers in the Children’s Hospital to have received the flu vaccine. Refusal is grounds for dismissal. Consider this draconian standing though from the patient’s viewpoint, and the viewpoint of their families. If you as a health care worker inadvertently bring an infectious disease into a patient room, even if you personally are not sick from that agent and they become sick, I would view you as liable in this situation for the patient’s complication, and all you did was to walk into that room!

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