A Pox On You? Hopefully Not!

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 

Genus/Virus  Disease  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  Orf  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  Yabapox  Localized skin tumors acquired from monkeys (rare): narrow host range: Found in West Africa 
Yatapoxvirus/Tanapox virus  Tanapox  Localized skin lesions probably from arthropod bites; common in parts of West Africa 


ICD-10-CM Coding Examples For Poxviruses

Category Code  Description
B03  Smallpox

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

B04  Monkeypox
B08  Other Viral Infections Characterized by Skin and Mucus Membrane Lesions, NEC 
B08.0  Other orthopoxvirus infections 
B08.01  Cowpox and vaccinia not from vaccine  
B08.010  Cowpox 
B08.011  Vaccinia not from vaccine 

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

B08.02  Orf virus disease 

Contagious pustular dermatitis Ecthyma contagiosum  

B08.03  Pseudocowpox, unspecified [milker’s node] 
B08.04  Paravaccinia, unspecified 
B08.09  Other orthopoxvirus infections 

Orthopoxvirus infection NOS 

B08.1  Molluscum contagiosum 
B08.6  Parapoxvirus infections 
B08.60    Parapoxvirus infection, unspecified 
B08.61  Bovine stomatitis 
B08.62  Sealpox 
B08.69  Other Parapoxvirus infections 
B08.7  Yatapoxvirus infections 
B08.70  Yatapoxvirus infection, unspecified 
B08.71  Tanapox virus disease 
B08.82  Yaba pox virus disease 

Yaba monkey tumor disease 


Other yatapoxvirus infections   

B08.8  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.

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