ORIGINAL RESEARCH

 

Identification and partial sequencing of a crocodile poxvirus associated with deeply penetrating skin lesions in farmed Nile crocodiles, Crocodylus niloticus

 

 

F.W. Huchzermeyer^I; D.B. Wallace^{II, III}; J.F. Putterill^II; G.H. Gerdes^II

^IP.O. Box 12499, Onderstepoort, 0110 South Africa
^IIOnderstepoort Veterinary Institute, Private Bag X05, Onderstepoort, 0110 South Africa
^IIIDepartment of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa

 

 

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ABSTRACT

When large numbers of crocodile skins were downgraded because of the presence of small pin pricklike holes, collapsed epidermal cysts were found deep in the dermis of juvenile crocodiles while forming cysts were observed in hatchlings. Histopathology of these forming cysts showed the presence of intracytoplasmic inclusions in proliferating and ballooning epidermal cells. Pox virions were seen in electron microscope preparations made from the scabs of such early lesions. The partial sequencing of virus material from scrapings of these lesions and comparison of it with the published sequence of crocodile poxvirus showed the virus associated with the deep lesions to be closely related, but different. To differentiate between the two forms of crocodile pox infection it is suggested that the previously known form should be called "classical crocodile pox" and the newly discovered form "atypical crocodile pox". The application of strict hygiene measures brought about a decline in the percentage of downgraded skins.

Keywords: Crocodylus niloticus, dermatitis, electron microscopy, genome sequencing, poxvirus

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Accepted for publication 19 February 2009-Editor

 

 

* Author to whom correspondence is to be directed. E-mail: crocvet@mweb.co.za