Poxviridae

Questions

1. Describe the general properties of Pox viruses?

2. Describe the Various genre of Pox viruses?

3. Describe the Orthopoxviruses that exist, including the disease/signs they cause?

4. Describe the Parapoxviruses and the diseases/signs they cause?

5. Describe the Unclassified Pox virus, including the disease/signs they cause?

6. How would you diagnose and prevent this disease?

Poxviruses are 300nm in size, enveloped, have a brick shape and are resistant to drying. They can be seen under the light microscope. Smallpox and molluscum contagiosum are the only two which do not have animal reservoirs, whereas others occur from zoonoses. The three main genre are the orthopoxvirus, paropoxvirus, and unclassified pox viruses. Belong to the first genre are: Variolla major, Variolla minor, Vaccinia virus, Monkey pox, and Cow pox. The 1^st 2 cause severe and mild small pox respectively. The 3^rd one is a virus used to immunise against small pox. Monkey pox causes disease which is different but not distinguishable from small pox, and the last one causes vesicular lesions in man. The parapoxvirus genre contains: Milker’s nodules virus and Orf viruses. The former causes isolated lesions in man, and the latter causes lesions in arm and forehand, which usually spontaneously heal. The unclassified genre is concerned with: molluscum contagiosum – and this causes lesions in skin  axilla + trunk. It is spread by contact and STD. Diagnosis is clinical, and also presence of viral inclusions in lesion isolates. Treatment is spontaneous healing, along with cryotherapy. Prevention is via small pox vaccine. Virus not destroyed in case outbreak due to bio terrorism.

Category: Microbiology Notes