Mycobacterium avium subspecies paratuberculosis confirmed following serological surveillance of small ruminants in Grenada, West Indies.

Surveillance for Mycobacterium avium subsp. paratuberculosis (Map) infection in small ruminants of Grenada was undertaken using a commercial enzyme-linked immunosorbent assay (ELISA). Among the 479 sheep tested, 11 (2.3%) were ELISA positive while only 1 out of 260 goats (0.3%) was ELISA positive. Five of the 12 ELISA-positive animals were also positive in a commercial agar gel immunodiffusion (AGID) assay, and 4 of these showed acid-fast rods consistent with Map in fecal smears. Two sheep that were test-positive by ELISA, AGID, and fecal smears were euthanized and necropsied. Both had gross and histological lesions of paratuberculosis affecting the ileocecal area of small intestines and adjacent lymph nodes. These tissues were successfully cultured in 2 of 3 variants of Middlebrook 7H10 medium. The identity of acid-fast organisms isolated from the tissues was confirmed as Map by multiplex conventional polymerase chain reaction. Using IS1311 amplification and Hinf I restriction digest analysis, isolates were identified as cattle (C) strains of Map. The current study describes Map infection in Grenada and confirms the presence of C type in sheep on the island of Carriacou. The low seroprevalence in clinically normal animals on the islands of Grenada and Carriacou suggests that control measures implemented in the near future may have a good chance of preventing spread of the infection.

Doxycycline treatment of asymptomatic dogs seropositive for Ehrlichia canis

In Grenada, West Indies dogs are at frequent exposure to the rickettsial pathogen, Ehrlichia canis, as demonstrated by high seroprevalence rates. However, many of these seropositive dogs are clinically normal. In this study we identified clinically normal, E. canis seropositive dogs and assigned half to an antibiotic treatment group and half to a no treatment group. All dogs were evaluated for the presence of E. canis DNA by PCR on whole blood before, during and after treatment. Only one seropositive dog was also PCR+ before treatment. Our results suggest that most clinically normal, E. canis seropositive dogs in a highly endemic geographic area are not concurrently infected and thus routine treatment of clinically normal, seropositive dogs is not warranted.