Mycobacterium avium infection in a Horse N Ian Hawkins Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

N History An 8 year old male QH gelding presented to the UFVMC on 8/18/07 with suspected anterior enteritis An 8 year old male QH gelding presented to the UFVMC on 8/18/07 with suspected anterior enteritis Improved on banamine and lidocaine until 8/25/07. Improved on banamine and lidocaine until 8/25/07. Abdominocentesis revealed elevated WBC count and TP Abdominocentesis revealed elevated WBC count and TP Surgery performed on 8/26/07 revealed multiple jejunal and ileal masses and necrotic section of jejunum Surgery performed on 8/26/07 revealed multiple jejunal and ileal masses and necrotic section of jejunum Due to poor prognosis, the patient was euthanized Due to poor prognosis, the patient was euthanized Necropsy was performed on 8/27/07 Necropsy was performed on 8/27/07 Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Gross Findings Gross Diagnosis: Gross Diagnosis: –Granulomatous enteritis, chronic, diffuse with multifocal transmural abscess formation, small intestine. Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Gross Findings Gross Diagnoses: Gross Diagnoses: –Renal papillary necrosis, chronic, multifocal, marked, Kidneys. –Mesenteric and colonic lymphadenomegaly. Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Microscopic Findings – Small intestine Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Small Intestine with Acid-Fast Stain Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Kidney and Liver Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Mesenteric lymph node Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Diagnoses Final Anatomic Diagnoses: Final Anatomic Diagnoses: 1.Granulomatous enteritis, chronic, multifocal, severe with abundant intralesional, acid-fast bacterial rods, small intestine. 2.Granulomatous lymphadenitis, chronic, multifocal, moderate, mesenteric lymph node. 3.Granulomatous typhlocolitis, chronic, multifocal, moderate to marked, cecum and colon. 4.Portal hepatitis, granulomatous, chronic, multifocal, moderate to marked, liver. 5.Renal papillary necrosis, chronic, multifocal, marked, kidneys. Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Polymerase Chain Reaction Paraffin-embedded sections of intestine were submitted to the NVSL in Ames, IA and Claus Buergelt’s lab at the University of Florida – performed by Elliot Williams. Paraffin-embedded sections of intestine were submitted to the NVSL in Ames, IA and Claus Buergelt’s lab at the University of Florida – performed by Elliot Williams. Results from both labs were positive for Mycobacterium avium Results from both labs were positive for Mycobacterium avium –16sRNA positive –IS1311 positive Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

PCR PCR using IS900 based primers for Mycobacterium avium ssp. paratuberculosis. PCR using IS900 based primers for Mycobacterium avium ssp. paratuberculosis. Tissue was positive using J1-J2 IS900 primers (nested primers). Tissue was positive using J1-J2 IS900 primers (nested primers). Johne’s? or a variant of M. avium ssp. paratuberculosis. Johne’s? or a variant of M. avium ssp. paratuberculosis. MapMap nest N MapN Neg P90/P91 J1/J2 Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Mycobacterium avium in Horses Infections in horses are uncommon but have been reported Infections in horses are uncommon but have been reported Typically occur in younger adult horses and predominantly affects the gastrointestinal tract; also the lungs and liver with less frequency Typically occur in younger adult horses and predominantly affects the gastrointestinal tract; also the lungs and liver with less frequency Clinically horses tend to have chronic weight loss, diarrhea, and hypoproteinemia. Clinically horses tend to have chronic weight loss, diarrhea, and hypoproteinemia. M. avium has been isolated from horses with Equine Granulomatous Enteritis, a sporadic idiopathic disease of young horses with similar clinical signs and lesions. M. avium has been isolated from horses with Equine Granulomatous Enteritis, a sporadic idiopathic disease of young horses with similar clinical signs and lesions. Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Mycobacterium infections in horses Gross findings: Gross findings: –Multifocal soft to firm transmural nodules throughout affected regions of the GI tract –Ulcerated mucosa Histopathology: Histopathology: –Granulomatous inflammation –High numbers of multinucleated giant cells Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Mycobacterium infections in horses Johne’s Disease in a horse? Johne’s Disease in a horse? –Horses have been experimentally infected with the organism; sporadic cases have been reported, but were unconfirmed and exceedingly rare. –A variant of M. avium ssp. paratuberculosis that horses maybe more susceptible to? Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Acknowlegements Barbara Sheppard, DVM, PhD, Dipl. ACVP Barbara Sheppard, DVM, PhD, Dipl. ACVP Elliot Williams Elliot Williams Giles R.G. Monif Giles R.G. Monif John Roberts, DVM, Dipl. ACVP John Roberts, DVM, Dipl. ACVP David Taylor, BVSc, Dipl. ACVP David Taylor, BVSc, Dipl. ACVP Fellow UF Pathology Residents Fellow UF Pathology Residents The UFVMC Histology lab staff The UFVMC Histology lab staff Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

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