Scrapie at Abattoir: Monitoring, Control, and Differential Diagnosis of Wasting Conditions during Meat Inspection

Abstract

Wasting disease in small ruminants is frequently detected at slaughterhouses. The wasting disorder is manifested by the deterioration of the nutritional and physiological state of the animal indicated by thinness, emaciation, and cachexia. Evidence of emaciation and cachexia, alone, are pathological conditions leading to carcass condemnation during an inspection. Several diseases are associated with a wasting condition, including scrapie, pseudotuberculosis, tuberculosis, paratuberculosis, Maedi Visna, and tumor diseases. On the other hand, parasitic diseases, nutrition disorders, exposure or ingestion of toxins, metabolic conditions, inadequate nutrition due to poor teeth, or poor alimentary diet are conditions contributing to poor body condition. Classical and atypical scrapie is naturally occurring transmissible spongiform encephalopathies in small ruminants. The etiological agent for each one is prions. However, each of these scrapie types is epidemiologically, pathologically, and biochemically different. Though atypical scrapie occurs at low incidence, it is consistently prevalent in the small ruminant population. Hence, it is advisable to include differential diagnosis of this disease, from other possibilities, as a cause of wasting conditions detected during meat inspection at the abattoir. This manuscript is a review of the measures in force at the abattoir for scrapie control, focusing on the differential diagnosis of gross lesions related to wasting conditions detected in small ruminants during meat inspection.

Use of immunohistochemistry and prion protein gene genotyping for detection of Scrapie in sheep in the state of Santa Catarina, Brazil

“…As described in other outbreaks in Brazil and the world, the disease occurred without an apparent macroscopic lesion. Loss of wool and weight can be related but are not characteristic of the disease (MARTINS et al, 2012;ESTEVES et al, 2021). Histological lesions in classic scrapie are at the brain stem (obex), characteristic of vacuolization of neurons and neuropil without inflammatory reaction, as described in this study.…”

Perspectives of economic losses due to condemnation of cattle and buffalo carcasses in the northern region of Brazil

“…113, paragraph 2. Cachexia is characterized as complex, and not easily defined, being considered a metabolic syndrome, consisting of progressive weight loss [ 44 , 45 ].…”

“…Injury rates are associated with inadequate handling of cattle, whether in loading, transporting or unloading. The greater number of wounds in the rear regions of cattle, which affect the quality of the meat, is possibly due to the use of inappropriate objects, such as shock sticks and pointed pieces, while driving the animals [ 45 – 47 ]. During loading and unloading, the lack of training of employees can cause disordered movement in animals, as well as stress [ 48 – 50 ], which which favors the appearance of injuries [ 51 – 53 ].…”

Prion Zoonoses

“…In addition, all rapid tests include a denaturation step of PrP Sc for subsequent detection by anti-PrP antibodies. A positive result obtained with these tests is not definitive, and it is necessary to confirm it by Western blot or IHC (Esteves et al 2021).…”