Clinical, humoral, and pathologic findings in adult alpacas with experimentally induced Corynebacterium pseudotuberculosis infection.
OBJECTIVE
To experimentally infect adult alpacas by ID inoculation of Corynebacterium pseudotuberculosis, follow the clinical and pathologic course of disease, and study the humoral response to infection.


METHODS
13 adult alpacas.


METHODS
9 alpacas were inoculated with 1.1 X 10(6) CFUs of C pseudotuberculosis from llama (n = 4) or alpaca (5) origin, and 4 alpacas were sham inoculated as controls. Alpacas were clinically observed after inoculation and euthanatized on days 16, 58, 93, or 128 after inoculation; necropsy examination and histologic evaluation were performed. An indirect ELISA, which made use of the C pseudotuberculosis cell wall as the antigen, was used to measure antibody titers in serum samples.


RESULTS
Alpacas had a persistent febrile response, a local severe inflammatory response, and leucocytosis (> 30 X 10(3) WBCs/microL). Internal abscesses that localized mainly in the renal lymph node were observed. Corynebacterium pseudotuberculosis was recovered from the inoculation site 1 week after inoculation and from internal abscesses at 58 days after inoculation. Initial lesions were typical pyogranulomas with central caseous necrosis, whereas later lesions consisted of connective tissue, mononuclear cells, abundant neutrophils, and liquefactive necrosis. Infected alpacas had detectable serum antibody titers starting on day 16 that persisted until day 93 after inoculation. Shaminoculated alpacas did not develop serum antibody titers, clinical signs of infection, or lesions.


CONCLUSIONS
Alpacas inoculated with C pseudotuberculosis developed abscesses at the inoculation site and internally in the renal lymph nodes, without lung lesions. Corynebacterium pseudotuberculosis isolates from llama and alpaca origin were found to be pathogenically indistinct.
Braga
Walter U
WU
Instituto Veterinario de Investigaciones Tropicales y de Altura IVITA, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Av. Circunvalación s/n cr. 28 San Borja, Lima, Perú.
Chavera
Alfonso E
AE
González
Armando E
AE
D000038:Abscess / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001831:Body Temperature; D002161:Camelids, New World / Q000276:immunology / Q000382:microbiology*; D003354:Corynebacterium Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D016925:Corynebacterium pseudotuberculosis / Q000254:growth & development* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006651:Histocytochemistry / Q000662:veterinary; D007958:Leukocyte Count / Q000662:veterinary; D008168:Lung / Q000473:pathology; D008198:Lymph Nodes / Q000473:pathology; D008199:Lymphadenitis / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D008297:Male; D009504:Neutrophils / Q000276:immunology
D000907:Antibodies, Bacterial