1. General Considerations

   1. Psorergatic mange is prevalent in Australia, New Zealand, South Africa and South America.
   2. It is a common skin condition of sheep but rarely causes skin disease in cattle.
   3. The mite burrows in the epidermis of sheep and cattle.
   4. The life cycle is completed on the host in about 35 days.
   5. The mite population is higher and the clinical signs are more severe during winter and spring.
   6. Transmission is by direct contact with the affected animal and indirect contact via premises and fomites.
   7. Mites cannot survive for more than a few days off the host.
   8. Psorergatic mange is not a zoonotic disease.

2. Cause

   1. Psorergates ovis: ovine
   2. Psorergates bos: bovine

3. Clinical Signs

   1. Ovine:
      1. Psorergatic mange has been eradicated from sheep in The U.S. Therefore, it is reportable.
      2. Clinically, the disease is characterized by intense pruritus, which results in chewing of the fleece over the lateral thorax, flanks and thighs. The wool will be matted, broken and absent in these areas.
      3. The affected skin is often very scaly.
   2. Bovine:
      1. Little or no pruritus.
      2. Subtle degrees of patchy alopecia and scaling.
      3. Psorergates bos can also be recovered from cattle with normal skin and hair coat.

4. Diagnosis

   1. History and characteristic clinical signs.
   2. Multiple skin scrapings: mites can be difficult to find.

5. Treatment

   1. Ovine:
      1. It is reportable. Call state veterinarian.
      2. Treat during summer (better results).
      3. Dips or sprays: 2 to 3 % lime sulfur, 0.2% malathion, 0.3% coumaphos, and 0.03% to 0.3% diazinon (a license is required to purchase diazinon in the USA).
      4. Dip twice at a 10-14-day intervals.
      5. Ivermectin has been reported to be effective in cattle.
   2. Bovine
      1. Treatment is not usually rendered.
      2. Ivermectin was reported to be effective.

References

Scott DW.  Parasitic Diseases.  In: Large Animal Dermatology.  Philadelphia, PA: W.B. Saunders, 1988;  225-226.