Comparison of postmortem inspection procedures for detecting caseous lymphadenitis of Australian sheep and goats

Abstract

Alternative postmortem inspection procedures for the detection of gross abnormalities due to Caseous Lymphadenitis (CLA) of sheep and goats were compared quantitatively against the current Australian Standard (AS4696). Studies on sheep and goats in Australia during 2016 addressed data gaps regarding current prevalence, combinations of multiple lesions within affected carcases and sensitivity of inspection procedures enabling a comparison of alternative with current procedures. Using these contemporary inspection data from 54 915 sheep and 48 577 goats a desktop study estimated the effect of implementing alternative procedures of reduced palpation from eleven carcase sites to the four sites most commonly affected. Under current procedures it was estimated that 86 sheep and 34 goat carcases with CLA lesions are missed per 10,000 carcases. Under alternative procedures it is estimated that an additional 48.4 sheep and 10.5 goat carcases with CLA lesions would be missed per 10 000 carcases. Of these, 38.2 sheep and 5.6 goat per 10 000 carcases would contain CLA only in routinely discarded, non-edible tissue sites. Hence, only an additional 10.2 sheep and 4.9 goat carcases per 10 000 inspected, with CLA in edible tissue sites are estimated to be missed. These alternative procedures have now been officially implemented in the Australian domestic standard.

Morphological Assessment of Concomitant Lesions Detected in Goat Herds Naturally Infected with Paratuberculosis (Johne’s Disease)

“…This reflects the invasion of infectious agents in the lymph node resulting from the drainage of products of a distant inflammation and their respective progression involving the node directly [26]. In the cases of Corynebacterium pseudotuberculosis compatible CLA, where LNs are the target organs, our results reported RPh, MD, and MA LNs as common lesion sites, which agrees with recent reports in goats [46,47].…”

“…Categorical variables were summarized using percentages and relative or absolute frequencies. The ages of the studied goats were categorized in the following groups: (0-12] months, (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) months, (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36) months, (36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48) months and >48 months. Chi-square test was used to contrast the association between two categorical variables.…”

“…The studied animals were between 7 and 121 months of age, with a mean of 29 months, median of 16.50 months, SD of 30.2 months and IQR of 16 months. The ages of the studied goats were categorized in the following groups: (0-12] months, (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) months, (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36) months, (36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48) months and >48 months in which 1, 21, 10, 2 and 4 animals were included, respectively. PTB granulomatous lesions were observed in 61.5% (24/39) of the animals affecting the MS LNs (Figure 1a and Table 2).…”

Molecular Characterization of Corynebacterium pseudotuberculosis Isolated over a 15-Year Period in Switzerland

“…In small ruminants, an infection with C. pseudotuberculosis leads to chronic pyogranulomatous lesions known as caseous lymphadenitis (CLA), characterized by abscess formation in superficial and visceral lymph nodes. The infection can generalize into different internal organs such as the lungs or the liver resulting in the visceral form of the disease [ 12 , 13 , 14 ]. Transmission primarily occurs after infection of superficial skin wounds with pus from abscesses that drain spontaneously [ 3 , 15 ].…”