Abstract
Infectious abortion in small ruminants poses a major veterinary and public health challenge in Egypt. This cross-sectional study investigated the prevalence and risk factors of brucellosis, listeriosis, and Rift Valley fever (RVF) as causes of ovine abortion in 150 ewes from rural flocks in Alexandria Province over a six-month period. Brucellosis was detected by the Rose Bengal Plate Test (RBPT) and confirmed by multiplex PCR (bcsp31, alkB, BMEI1162 gene targets). Listeria spp. were isolated from aborted fetuses, vaginal discharge, and placenta using selective enrichment and identified biochemically and by inlA PCR. RVF antibodies were screened by competitive ELISA. Brucellosis showed the highest overall seroprevalence (19.3%), followed by listeriosis (12.7%) and RVF (5.3%); the difference was statistically significant (χ² = 13.502, p = 0.0012). Among Listeria isolates, L. monocytogenes was predominant (42.1%), followed by L. grayi (26.3%), L. ivanovii (15.7%), and L. innocua (15.7%). The absence of a dedicated kidding area was the only management factor significantly associated with higher listeriosis prevalence (χ² = 6.802, p = 0.009). Age group, breed, housing type, disinfection practice, and vector presence showed no statistically significant association with any disease. These findings confirm the enzootic status of brucellosis and listeriosis in Alexandria Province and underscore the need for integrated biosecurity strategies and strengthened zoonotic surveillance.

Key words: Ovine abortion; Brucellosis; Listeriosis; Rift Valley fever; Risk factors