Evaluations of the methods involved in surveillance and diagnosis of ruminants' paratuberculosis in Romania are presented. The methods used were: complement fixation test (CFT), indirect enzyme-linked immunosorbent assay (iELISA-abs), enzyme immunoassay for the detection of bovine IFN-γ (EIAs-γ-IFN), agar gel immunodiffusion (AGID), delayed-type hypersensitivity (DTH), bacterioscopicy (B), and histological tests (HT). Samples were obtained from 2400 cattle of which 787 were infected and 595 sheep, all from infected flocks.

METHOD	CATTLE		SHEEP
	No. of samples	P+D reactions	No. of samples	P+D reactions
CFT	2400	119	595	227
AGID	125	114	55	21
iELISA-abs	2400	190	595	74
DTH	54	12	20	14
EIAs-γ-IFN	54	15	0	0
AP, B, HT	31	26	55	38
P-positive, D-doubtful, N-negative, AP-anatomopathological findings

The number of positive and doubtful results obtained in CFT was greater in sheep samples (38.1%) than the cattle samples (5%). ELISA showed fewer positive results: cattle 7.9% and sheep 12.4%.The percentage of cross-reactions (false-positve) was greater in sheep than in cattle. The AGID used in this study was performing approximately equal to CFT. The difference in results of the assays assessing cell-mediated immune response (DTH and EIAs-γ-IFN) was a non-significant, though EIA-γ-IFN was more sensitive than DTH with 5.5% positive. The data processing from the confirmatory tests (bacterioscopy and histology) showed that from 31 examined cattle, acid-fast bacilli were found in faeces and in the tissues of 38.7% of the subjects and only in smears from the intestinal affected mucosa and cut-surfaces of mesenteric lymph nodes in 29% of the subjects.In sheep samples the percentage of the faecal shedders was greater than cattle though in investigated sheep the specific lesions were more discrete than those observed in cattle.