A Pox On You? Hopefully Not!

Becky Buegel, RHIA, CDIP, CHP Medical Coding Leave a Comment

A Pox On You? Hopefully Not!

Recent media reports document an increase in suspected and confirmed cases of the monkeypox virus. Monkeypox, first detected in lab monkeys in 1958, may have earned its moniker from the lab monkeys, but it’s actually thought it originally spread to humans from wild animals like rodents; today’s thinking is that it’s either spread by wild animals or from contact with other infected humans. Historically, most cases were confined in countries located on the African continent; however, cases outside of Africa have recently been confirmed in EU/EEA countries like Denmark, Sweden, and the Netherlands. As of May 16, 2022, Portugal had five confirmed cases and more than 20 suspected cases. *

Thinking about the word “pox”, I decided to do a little research (certainly not scientific) myself, starting with the definition of the word “pox.” According to Google’s English dictionary, Oxford Languages, the word “pox” is a noun that means, “any of several viral diseases producing a rash of pimples that become pus-filled and leave pockmarks on healing.” Sounds delightful – NOT!

According to Wikipedia, there are 83 species in the poxvirdae family which are divided into 22 genera (plural of genus). Four genera of these poxviruses can infect humans. They are as follows:

  • Orthopox – most commonly includes: smallpox virus; vaccinia virus; cowpox virus; monkeypox virus; and rabbitpox virus.
  • Parapox – includes: orf virus; pseudocowpox virus, and bovine papular stomatitis virus – BPSV. BPSV is a mild “farmyard” pox which can spread from infected cattle to milkers, farmers, and veterinarians.
  • Yatapox – including tanapox virus and yaba monkey tumor virus. Diseases associated with this genus include histiocytomas.
  • Molluscipox – which includes only molluscum contagiosum virus (MCV). MCV affects approximately 200,000 humans annually; it is also known as “water warts.”

You may be wondering why you didn’t see chickenpox listed in any of the above four genera. Chickenpox is not really a true pox virus and it is actually caused by herpesvirus varicella zoster.

Monkeypox and smallpox share the same genus – that of Orthopox. Cases of monkeypox were usually “kept under control” by the smallpox vaccination because of the viruses shared makeup. History cannot positively identify when the first case of smallpox was identified, though the earliest suspected case was diagnosed circa 1150 BCE in Pharaoh Ramses V, who is thought to have died from the disease. It is also thought smallpox transferred to Europe around the early 8th century and then to the Americas in the early 16th century, where it is thought to have caused the deaths of 3.2 million Aztecs within the first 2 years of its introduction. The high death toll is believed to be due to the population’s total lack of exposure to the disease before then. The last recorded case of smallpox occurred in Somalia in 1977, after a world-wide effort was made to vaccinate everyone.

Current thinking is that monkeypox is spread by close contact to bodily fluids, such as saliva. Almost all recently reported cases involve men aged 20-50, many of whom are identified as men who have sex with men (MSM), though monkeypox is not currently considered an STD.

Several poxviruses, including the vaccinia, myxoma, tanapox and raccoon viruses are presently being studied for their therapeutic potential in treating various human cancers.

Even though the reported cases of suspected/confirmed cases of monkeypox are rising, health authorities around the globe are not expecting an epidemic nor pandemic. Most cases of monkeypox are mild and improve without treatment, though it remains contagious, until the poxes scab, the scabs fall off, and a new layer of skin forms.

Human Poxvirus Infections 



Features and Epidemiology 

Orthopoxvirus/variola virus 

Smallpox (variola) 

Globally eradicated: Narrow host range 

Variola major 

Codes to smallpox 

Generalized infection with pustular rash; case-fatality rate 10 to 25% 

Variola minor 

Codes to smallpox 

Generalized infection with pustular rash; case-fatality rate less than 1% 

Orthopoxvirus/vaccinia virus 

Vaccinia infection as a complication of vaccination 

Usually, a local pustule, slight malaise. Rarely, eczema vaccinatum or generalized vaccinia (low mortality); progressive vaccinia (high mortality in immunocompromised vaccinees); postvaccinial encephalitis (high mortality): frequently used as a vaccine vector 

Orthopoxvirus/monkeypox virus 

Human monkeypox 

Generalized infection with pustular rash; case-fatality rate in humans 15%: numerous animal hosts, e.g. squirrels, anteaters: found in Central and West Africa 

Orthopoxvirus/cowpox virus 

Human cowpox infection 

Localized ulcerating lesion on the skin, usually acquired from cats or cows: found in Asia and Europe 

Parapoxvirus/milker’s nodule virus 

Milker’s nodule 

Trivial localized nodular infection on the hands acquired from cows 

Parapoxvirus/orf virus 


Localized papulo-vesicular lesion on the skin acquired from sheep: worldwide distribution 

Molluscipoxvirus/molluscum contagiosum virus 

Molluscum contagiosum 

Multiple benign nodules in skin 

Yatapoxviru/Yabapox virus 


Localized skin tumors acquired from monkeys (rare): narrow host range: Found in West Africa 

Yatapoxvirus/Tanapox virus 


Localized skin lesions probably from arthropod bites; common in parts of West Africa 


ICD-10-CM Coding Examples For Poxviruses

Category Code 




Note: In 1980, the 33rd World Health Assembly declared that smallpox had been eradicated. The classification is maintained for surveillance purpose. 




Other Viral Infections Characterized by Skin and Mucus Membrane Lesions, NEC 


Other orthopoxvirus infections 


Cowpox and vaccinia not from vaccine  




Vaccinia not from vaccine 

Excludes vaccinia (from vaccination) (generalized) (T88.1


Orf virus disease 

Contagious pustular dermatitis Ecthyma contagiosum  


Pseudocowpox, unspecified [milker’s node] 


Paravaccinia, unspecified 


Other orthopoxvirus infections 

Orthopoxvirus infection NOS 


Molluscum contagiosum 


Parapoxvirus infections 


Parapoxvirus infection, unspecified 


Bovine stomatitis 




Other Parapoxvirus infections 


Yatapoxvirus infections 


Yatapoxvirus infection, unspecified 


Tanapox virus disease 


Yaba pox virus disease 

Yaba monkey tumor disease 


Other yatapoxvirus infections   


Other specified viral infections characterized by skin and mucus membrane lesions 

Enteroviral lymphonodular pharyngitis        

Foot-and-mouth disease 

Poxvirus NEC 

The ICD-10-CM codes noted on above chart pertain to the poxviruses discussed in the blog and are examples only. The list of codes is in no way complete. As always, coders should review chart documentation and refer to the ICD-10-CM book (or encoder) to make certain the correct code is assigned, based on documentation found in the patient record, and following any instructional notes found in the coding book (or encoder) itself. 


Key Words/ Abbreviations

BC – Before Christ

BCE – Before the Common Era

EU – European Union

EEA – European Economic Area

Pox – In addition to “any of several viral diseases ….”, “pox” can also mean a disastrous evil or curse.

Leave a Reply

Your email address will not be published. Required fields are marked *

Sign Up For MRA Blog Updates!

Recent Posts