    vaccinia virus (vacv or vv) is a large, complex, enveloped virus belonging to the poxvirus family. it has a linear, double-stranded dna genome approximately 190 kbp in length, and which encodes approximately 250 genes. the dimensions of the virion are roughly 360 Ã 270 Ã 250&nbsp;nm, with a mass of approximately 5-10 fg. vaccinia virus is the active constituent of the vaccine that eradicated smallpox, making it the first human disease to be eradicated. this endeavour was carried out by the world health organization under the smallpox eradication program. post eradication of smallpox, scientists study vaccinia virus to use as a tool for delivering genes into biological tissues (gene therapy and genetic engineering). in the early 21st century, due to concerns about smallpox being used as an agent for bioterrorism, there was renewed interest in studying vaccinia virus. == classification of vaccinia infections == in addition to the morbidity of uncomplicated primary vaccination, transfer of infection to other sites by scratching, and post vaccinial encephalitis other complications of vaccinia infections, may be divided into the following types: :* generalized vaccinia :* eczema vaccinatum :* progressive vaccinia (vaccinia gangrenosum, vaccinia necrosum) :* roseola vaccinia ==origin== vaccinia virus is closely related to the virus that causes cowpox; historically the two were often considered to be one and the same.{{cite journal |author=huygelen c |title=jenner's cowpox vaccine in light of current vaccinology |language=dutch; flemish |journal=verh. k. acad. geneeskd. belg. |volume=58 |issue=5 |pages=479â536; discussion 537â8 |year=1996 |pmid=
Genetic_engineering Poxviruses Smallpox Vaccines Vaccinia Virus-related_cutaneous_conditions