Lesions in Guinea Pigs Infected with Coxiella burnetii Strain M-44

Abstract

Guinea pigs inoculated with the live M-44 vaccine strain of Coxiella burnetii were examined grossly and microscopically for the presence of Q fever-related lesions. Mild myocarditis was observed in 38% of the infected animals but in none of the control animals. Livers showed significant incidence of hepatitis, necrosis, and granuloma formation, especially during the first eight days of the infection. A much lower incidence of splenitis was also found but was considered to be of borderline significance. Generally, lesions were mild in nature, and none seemed to endanger the life of the animal or to cause observable distress.

Correlation of plasmid type and disease caused by Coxiella burnetii

“…The isolates are characterized primarily by their ability to react with sera from animals hyperimmune to phase I or II Nine Mile C. burnetii. No other assay for virulence is available, although attempts to correlate virulence with guinea pig pathology have been made (5).…”

Q fever and Coxiella burnetii: a model for host-parasite interactions.

“…The ready susceptibility of guinea pigs to infection by C. burnetii has made the animal a useful model for studying the pathobiology of Q fever. Guinea pigs infected with a low-virulence strain of C. burnetii (Grita M-44) developed mild endocarditis, hepatitis, and granulomatic and necrotic livers (93,94). Animals infected with the more virulent Nine Mile strain had elevated blood glucose and greater activities in serum of alkaline phosphatase, glutamic oxalacetic transaminase, and ,B-hydroxybutyric dehydrogenase 3 to 5 days p.i.…”

Coxiella burnetii: Host and bacterial responses to infection

“…This vaccine was capable of causing adverse reactions in humans and caused myocarditis, hepatitis, liver necrosis, granuloma formation, and splenitis in guinea pigs [90]. Human vaccinees did not develop antiphase I antibodies and anti-phase II levels were variable and at low titer.…”