Pathologic changes in lizards (Agama agama) experimentally infected with Dermatophilus congolensis

Area of Science:

• Veterinary Pathology
• Herpetology
• Microbiology

Background:

• Dermatophilus congolensis is a bacterial pathogen known to affect various animal species.
• Information on D. congolensis infections in reptiles, specifically lizards, is limited.
• Understanding reptilian susceptibility to bacterial infections is crucial for conservation and husbandry.

Purpose of the Study:

• To investigate the pathogenicity of Dermatophilus congolensis in captive Agama agama lizards.
• To characterize the gross and histopathological lesions induced by experimental D. congolensis inoculation.
• To determine the persistence of D. congolensis in infected lizards.

Main Methods:

• Adult Agama agama were experimentally inoculated with D. congolensis via subcutaneous, intramuscular, and intraperitoneal routes.
• Lesions were monitored, and tissue samples were collected for bacterial culture and histopathological examination.
• Cultures were performed at various time points post-inoculation to assess bacterial persistence.

Main Results:

• Experimental inoculation resulted in pyogranulomatous and necrotic lesions at inoculation sites.
• Dermatophilus congolensis was consistently re-isolated from lesions up to 75 days post-inoculation.
• Histopathology revealed granulomatous caseous abscesses in the dermis, subcutaneous tissue, and liver, along with dermal edema and muscular degeneration/necrosis.

Conclusions:

• Dermatophilus congolensis is pathogenic to Agama agama, inducing significant tissue damage and persistent infections.
• The liver and musculature are susceptible target organs for D. congolensis in this lizard species.
• Absence of epidermal lesions suggests D. congolensis primarily affects deeper tissues in lizards.