Utility assessment of an Enzyme‐linked immunosorbent assay for detection of subclinical cases of caseous lymphadenitis in small ruminant flocks

Abstract

The actual prevalence of CLA (caseous lymphadenitis) in small ruminant flocks is underestimated in many countries, and because it is not a notifiable disease, it will continue to spread without data and information about its real economic impact. The difficulty in the accurate identification of the causative agent in internal subclinical cases allows the disease to spread within and between flocks. This research intends to assess the utility of an ELISA (enzyme‐linked immunosorbent assay) test in the detection of internal subclinical cases of CLA in farms and to simultaneously add data on the seroprevalence of the disease in Portugal. Sera from 756 small ruminants, 70% sheep (528/756) and 30% goats (228/756) were screened for antibodies against Corynebacterium pseudotuberculosis using the ELISA technique based on a recombinant phospholipase D (ELITEST CLA # CK105A®). The animals showing internal lesions (n ꞊ 58) were sampled for the identification of the aetiological agent. In this investigation, the prevalence of CLA was 34% (258/756), with the ELISA test showing a low specificity (78%) and high sensitivity (100%). The proof was able to detect 57% (13/23) of subclinical cases of CLA confirmed by postmortem examination and conventional PCR (polymerase chain reaction). The results also reveal that goats have a higher propensity for the disease, and dairy farms and non‐extensive production units appear to be more susceptible to CLA. This research clarifies an actual problem and pointed out the importance of CLA in small ruminant herds in Portugal. Finally seems to demonstrate that the ELISA test is a good diagnostic tool for use in CLA eradication programmes.

Skin disease in goats (Capra aegagrus hircus): a retrospective study of 358 cases at a university veterinary teaching hospital (1988–2020)

“…Corynebacterium pseudotuberculosis is well-documented as causing abscesses in goats, both internally and subcutaneously . 12,21,22 Abscesses affecting the skin, not always cultured, often were assumed in the medical records to be caused by C. tuberculosis; however, where performed, other bacteria, such as S. aureus were isolated on culture, as has been noted previously. 5,22 It is interesting to note that the number of goats with nonabscess manifestations of pyoderma such as pustules, folliculitis and furunculosis as reported previously 2 was nearly the same as the goats with abscesses.…”

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

“…CLA is a major problem in countries with intensive small ruminant farming, such as Australia and New Zealand, causing considerable economic losses in ovine and caprine herds through reduction of wool, meat and milk production [ 2 , 3 , 25 ]. Previous research suggests an average prevalence of 26% in Australia [ 25 ], 34% in Portugal [ 26 ], 43.7% in Brazil [ 27 ] and 21% in Canada [ 28 ]. Vaccination programs have been described to lower the occurrence of CLA [ 25 ].…”

Comparative Diagnosis of Caseous Lymphadenitis in Sheep by Molecular and ELISA Method

“…Dünyanın farklı ülkelerinde adı geçen hastalıkla ilgili ELISA yöntemi kullanılarak gerçekleştirilen çalışmalarda Brezilya'da %78.9-%93.35 (19)(20)(21), Portekiz'de %34 (22), Mısır'da %83.6 (15) olduğu bildirilmiştir. Yapılan diğer çalışmalarda Ürdün'de %15.3 (14), Hindistan'da %2.31-%4.38 (23,24), Venezuala'da %8 (25), Mısır'da %6.75 (26) ve Brezilya'da %43.7 (27) olduğu bildirilmiştir.…”

“…Bu çalışmada ELISA yöntemiyle %18.9 oranında prevalans tespit edilmiştir. Elde edilen bu so-nuç bazı araştırıcıların (15,(19)(20)(21)(22) sonuçlarından düşük olduğu görülürken, Al-Rawashdeh ve ark. ( 14) bulgularıyla yakın oranlarda olduğu tespit edilmiştir.…”