Orthopoxvirus inclusion bodies
Orthopoxvirus inclusion bodies are aggregates of stainable protein produced by poxvirus virions in the cell nuclei and/or cytoplasm of epithelial cells in humans. They are important as sites of viral replication.{{cite journal | date = May 2012 | title = Formation of orthopoxvirus cytoplasmic A-type inclusion bodies and embedding of virions are dynamic processes requiring microtubules | journal = J Virol | volume = 86 | issue = 10| pages = 5905–14 | doi = 10.1128/JVI.06997-11 | pmid=22438543 | pmc=3347259 | last1 = Howard | first1 = AR | last2 = Moss | first2 = B}}Fenner, F., Witte, K.R., and Dumbell, K.R. The Orthopoxviruses. Academic Press, San Diego, 1989.
Morphology
Morphologically there are two types of Orthopoxvirus inclusion bodies, Type-A inclusion bodies and Guarnieri bodies. Type-A inclusion bodies are found only in certain poxviruses like cowpox.{{cite journal | last1 = Leite | first1 = JA | last2 = da Fonseca | first2 = FG | last3 = de Souza Trindade | first3 = G | last4 = Abrahão | first4 = JS | last5 = Arantes | first5 = RM | last6 = de Almeida-Leite | first6 = CM | last7 = Santos | first7 = JR | last8 = Guedes | first8 = MI | last9 = Ribeiro | first9 = BM | last10 = Bonjardim | first10 = CA | last11 = Ferreira | first11 = PC | last12 = Kroon | first12 = EG | date = Apr 2011 | title = A-type inclusion bodies: a factor influencing cowpox virus lesion pathogenesis | journal = Arch Virol | volume = 156 | issue = 4| pages = 617–28 | doi=10.1007/s00705-010-0900-0| pmid = 21212997 | s2cid = 33135261 }} The Guarnieri bodies are found in all poxvirus infections and their presence is diagnostic.{{cite journal |author=Riedel S |title=Smallpox and biological warfare: a disease revisited |journal=Proc (Bayl Univ Med Cent) |volume=18 |issue=1 |pages=13–20 |date=January 2005 |pmid=16200143 |pmc=1200695 |doi=10.1080/08998280.2005.11928026}} The diagnosis of an orthopoxvirus infection can also be made rapidly by electron microscopic examination of pustular fluid or scabs. However, all orthopoxviruses exhibit identical brick-shaped virions by electron microscopy.{{citation needed|date=November 2022}}
Guarnieri bodies are named for Giuseppe Guarnieri, (1856–1918) an Italian physician who first described them.{{cite book |author1=Forbis, Pat |author2=Bartolucci, Susan L. |author3=Stedman, Thomas Lathrop |title=Stedman's medical eponyms |publisher=Lippincott Williams & Wilkins |location=Hagerstwon, MD |year=2005 |pages=294 |isbn=0-7817-5443-7 }}