page_title: Canarypox
section_title: Symptoms
hierarchical_section_title: Canarypox / Symptoms
caption_attribution_description: English: 23.3. Electron micrograph of an epidermal cell with cytoplasmic degeneration and numerous poxvirus particles (V); a second cell has marginated chromatin (MC) and a filamentous matrix (F) in the nucleus, which corresponds to the central nuclear clearing seen histologically. Insert shows typical poxvirus particles. (Courtesy of D. A. Gregg.)
context_page_description: Canarypox virus is an Avipoxvirus and etiologic agent of canarypox, a disease of wild and captive birds that can cause significant losses. Canarypox can enter human cells, but it cannot survive and multiply in human cells. There is a live viral vaccine available which may have beneficial properties against human cancer when used as a mammalian expression vector. Furthermore, the POXIMUNE® C vaccine does offer direct protection against CNPV in susceptible birds.
  Generally CNPV is considered a disease of songbirds, such as canaries, magpies and nightingales, and is associated with higher mortality rates when compared to other avian pox viruses. In some instances, mortality approaches 100%. Avian pox viruses also cause significant economic losses in domestic poultry and remain a problem in the conservation of endemic bird species inhabiting islands.
  The general symptoms of CNPV are similar to those of other species of avian pox viruses and are characterised by pustules and diphtheria or pneumonia-like symptoms.
context_section_description: CNPV symptoms often show two main forms. That is either dry (cutaneous) and/or wet (diphtheritic) symptoms (both forms can occur at the same time).
  The dry form is the most frequently observed. At the beginning of the disease, small white/yellow blisters form on the uncovered parts of the skin. As the disease progresses blisters get progressively larger and form nodules where the virus can multiply. When the nodules coalesce and burst, scabs are formed leaving rough, dry and pigmented areas on the skin where the nodules were.
  This form of the disease is usually mild and does not cause death. The chances of mortality increase when the dry form occurs together with the wet (diphtheritic) form. The wet form symptoms include an enlarged thymus and obstructed lungs, sinuses and trachea with white areas of necrotic tissue. This results in restricted air intake and the potential for suffocation. It has also been observed that some birds may also experience thickened eyelids, air-sacks and enlarged spleens.
  Observations under the microscope have shown that the lesions are characterised by epithelial proliferation and hypertrophy in the viral infected areas.  Characteristics of avian pox include the formation of intracytoplasmic inclusion bodies ('Bollinger bodies') which are composed of mononuclear inflammatory cells and have been detected in the thymus, spleen, bone marrow, middle ear and air sac. Similar inclusion bodies which are associated with inflammation have also been seen in the epidermis, feather follicles, sinuses and oral mucosa lining.
  Apart from the symptoms mentioned above, more general signs of infection include weight loss, loss of feathers and scaly skin on the head, neck and back. Secondary bacterial infections are common with both forms of the disease, having the potential to cause pneumonia or other bacterial infections at the sites of blistering.
caption: Electron micrograph of an epidermal cell showing Poxvirus infection
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