Evidence of in-utero Mycobacterium avium subsp. paratuberculosis infection in two pregnant goats: PCR detection, bacterial isolation, and molecular genotyping.

IMPORTANCE

In-utero transmission of Johne's disease (JD), a chronic enteric condition caused by Mycobacterium avium subspecies paratuberculosis (MAP), has been reported. However, no study to date has confirmed in-utero transmission of MAP to fetuses in clinically infected Korean black goats.

OBJECTIVE

To provide evidence of in-utero transmission in two clinically JD-infected pregnant goats and their fetuses through polymerase chain reaction (PCR) detection, bacterial isolation, and molecular epidemiological characterization.

METHODS

Two pregnant goats were diagnosed with JD through clinical assessment, enzyme-linked immunosorbent assay, PCR detection, and bacterial culture. MAP isolates were genotyped using IS1311 PCR-restriction enzyme analysis and the mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) method.

RESULTS

ISMav02 gene was detected in the jejunum, mesenteric lymph nodes (MLN), and placentomes of both goats. In addition, positive bands were observed in the cecum and colon tissues from Goat #2. All fetal intestine samples from both goats were positive, while the umbilical cords were positive in one fetus from each goat. Two MAP isolates were obtained: one from the placentome (Goat #1) and the other from the MLNs (Goat #2). Genotyping revealed two distinct cattle-type strains, including INRA Nouzilly MIRU-VNTR (INMV) 248 (novel type) and INMV 13.

CONCLUSIONS AND RELEVANCE: This study provides the first direct evidence of in-utero MAP infection in clinically JD-infected pregnant goats in the Republic of Korea. Two distinct MIRU-VNTR genotypes were identified, including a novel MAP strain, highlighting the need for improved management strategies to prevent vertical transmission of JD and address genetic diversity within goat herds.