NAVLE Hemic and Lymphatic

Camelidae and Cervidae Caseous Lymphadenitis Study Guide

Caseous lymphadenitis (CLA) is a chronic, contagious bacterial infection caused by Corynebacterium pseudotuberculosis.

Overview and Clinical Importance

Caseous lymphadenitis (CLA) is a chronic, contagious bacterial infection caused by Corynebacterium pseudotuberculosis. While traditionally recognized as a major disease of small ruminants, CLA has emerged as a significant health concern in both Old World and New World camelids, as well as various cervid species. In camelids, the disease presents unique challenges due to its insidious nature and preference for internal organ involvement, making diagnosis particularly difficult. The disease causes substantial economic losses through mortality, reduced productivity, carcass condemnation, and culling of affected animals.

Virulence Factor Function Clinical Significance
Phospholipase D (PLD) Primary exotoxin; catalyzes breakdown of sphingomyelin in cell membranes Causes vascular damage, dermonecrosis, and leucotoxic effects; key virulence determinant
Mycolic acids Cell wall components providing structural integrity and resistance Enable survival within macrophages and environmental persistence
Lipid surface layer Thick, flocculant outer lipid layer Highly pyogenic; leads to thick-walled abscess formation

Etiology and Pathogen Characteristics

Causative Agent

Corynebacterium pseudotuberculosis is a Gram-positive, non-motile, facultatively anaerobic, pleomorphic coccobacillus belonging to the Actinomycetaceae family. The organism is closely related to C. diphtheriae and C. ulcerans, sharing similar mycolic acid content in the cell wall that contributes to environmental persistence.

Biovar Classification

Two distinct biovars exist based on nitrate reduction ability:

You've been studying hard

Create a free account to keep reading

Free accounts get 5 articles/day + daily practice question

Join 14,000+ vet students already studying with NavleExam.

No credit card needed — free account takes 30 seconds.

Create Free Account — Keep Reading Already have an account? Log in
or skip signup — just get daily questions

No spam. One question per day. Unsubscribe anytime.

NAVLE Exam Prep Platform

Everything you need to pass the NAVLE

10,000+ Practice Questions
Exam-style with full explanations
Past Exam Papers
Real previous exam questions
Flashcard Mode
Species & topic quick review
High-Yield Study Guides
What's actually on the exam
Start Free Trial → See Plans & Pricing No credit card required to start