Immune responses to Staphylococcus aureus and Psoroptes ovis in sheep infected with P. ovis--the sheep scab mite

Area of Science:

• Veterinary Parasitology
• Immunology
• Sheep Health

Background:

• Sheep scab, caused by Psoroptes ovis mites, can lead to secondary bacterial infections.
• Staphylococcus aureus is a common colonizer of P. ovis lesions in sheep.

Purpose of the Study:

• To compare clinical signs, lesion size, and immune responses to P. ovis and S. aureus.
• To investigate the impact of secondary S. aureus infection on the immune response to P. ovis.

Main Methods:

• Comparison of clinical signs and lesional area in P. ovis-infested sheep with and without S. aureus.
• Detection of specific IgG and IgE antibody responses to S. aureus and P. ovis antigens.

Main Results:

• No significant differences in clinical signs or lesional areas were observed between S. aureus-positive and -negative sheep.
• An IgG antibody response to S. aureus (targeting ~36, 38, 50, 65 kDa antigens) was detected in S. aureus-positive sheep.
• An IgE antibody response to P. ovis was detected in S. aureus-positive sheep, but not in S. aureus-negative sheep.

Conclusions:

• Secondary S. aureus infection does not exacerbate clinical sheep scab but modulates the host immune response.
• The presence of S. aureus induces a specific IgG response to the bacteria and an IgE response to the mite in sheep.