Neonatal diarrhea in small ruminants: AHL pathology diagnoses, 2018-2020

Josepha DeLay, Andrew Brooks, Emily Brouwer, Rebecca Egan, Murray Hazlett, Amanda Mansz, Jan Shapiro, Heindrich Snyman, Maria Spinato, Margaret Stalker 

Animal Health Laboratory, University of Guelph, Guelph, ON.   

AHL Newsletter 2020;24(2):6. 

 
Between January 1, 2018 and May 1, 2020, diarrhea was identified in 35 postmortem and/or histopathology submissions of neonatal goat kids or lambs (age 1-14 days, average 8 days) submitted to the AHL. These included 29 (83%) caprine and 6 (17%) ovine cases. A consistent set of ancillary diagnostic tests was carried out on 22/35 (63%) cases, all of which had postmortem examination done at the AHL. The test panel included: histopathology, fecal sucrose wet mount, bacterial culture of small and large intestine, and rotavirus and coronavirus PCR tests on intestinal mucosa or content. For the remainder of the cases, histopathology plus various combinations of these same tests were requested by the submitting veterinarian.   

Etiologic agents of neonatal diarrhea identified in this group are listed in Table 1. A single enteric pathogen was confirmed in the majority of cases [22/29 (76%) goat kids and 4/6 (67%) lambs]. Cryptosporidium spp was the most frequently identified cause of diarrhea in neonates of both species and was detected in 12/29 (41%) goat kid cases and 4/6 (67%) lamb cases. Concurrent rotavirus enteritis was present in 3 of the goat cases. Of the 4 lambs with cryptosporidiosis, concurrent coccidiosis was identified in one 14-day-old animal, and concurrent colibacillosis was present in one 7-day-old lamb.  

Rotavirus A or B was the sole pathogen associated with neonatal diarrhea in 2 young (1 and 2-day-old) kids. Coronavirus was not detected in any of the cases. Of the 10 E.coli cases in both species, 6 (67%) bacterial isolates were confirmed by genotyping as verotoxigenic (VTEC) or enteropathogenic (EPEC) serotypes. Other bacteria identified in 2 neonates with diarrhea included Clostridium perfringens and C. difficile, although the clinical significance of either isolate was not confirmed. Conditions affecting other body systems were present concurrently with neonatal diarrhea in 6/29 (21%) goat kids and 1/6 (17%) lambs, and included bacterial pneumonia and septicemia. 

Table 1. Etiologic agents identified (number of cases) and age range of affected animals (in days, D) in 35 AHL small ruminant neonatal diarrhea pathology submissions, 2018-2020. 

This pathology case review provides a reminder of the common causes of neonatal diarrhea in kids and lambs, and of the tests available for diagnostic evaluation in both clinically-affected live animals and postmortem cases.   AHL