Isospora suis Infection in Nursing Pigs

Peter Moisan

North Carolina Department of Agriculture

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

Case History

• Herd of several hundred sows.

• Farrow-to-finish operation.

• Diarrhea in preweaned piglets for many months.

• Various diagnoses in the past.

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

Case History (cont.)

• The current outbreak involved 10-15-day-old piglets.

• Morbidity 50% and mortality 10-20%.

• Territoriality did not change (pigs were not very weakened by diarrhea).

• Survivors were stunted and underweight.

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

Gross Lesion

• Regionally extensive necrotizing enteritis.

• Often with pseudomembrane.

• Pasty tan (butterscotch pudding-like) feces.

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

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

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

Microscopic Lesion

• Acute, severe, necrotizing, regionally extensive enteritis with villous attenuation, regeneration, and intracytoplasmic coccidia.

• All coccidian life stages were represented.

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

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

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

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

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

Life Cycle of Isospora suis

• Oocysts are shed in the feces and sporulate in a few days.

• Sporulated oocysts are ingested.• Oocysts excyst and release sporozoites that

infect the small intestinal enterocytes.• Merozoites are produced by endodyogeny of

the sporozoites and produce several generations that infect additional enterocytes.

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

Life Cycle (cont.)

• Merozoites go through merogony to form gamonts.

• Microgametocytes and macrogametocytes fuse by gametogeny to form new non-sporulated oocysts.

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

Significance of Piglet Coccidiosis

• This is a syndrome that occurs “between other scours syndromes”.

• Pigs are too young for some scours agents and too old for others.

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

Significance (cont.)

• Pigs develop coccidiosis at 10-14 days of age. • If younger, we are more likely looking at:• Clostridium difficile.• Clostridium perfringens Type A or Type C.• Colibacillosis.• TGE.• Rotavirus.

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

Significance (cont.)

• Pigs develop coccidiosis at 10-14 days of age.• If older (post-weaning), we are more likely

looking at:• Salmonella.• Brachyspira.• Lawsonia.• Rotavirus.

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

Significant Diagnostic Tips

• Pasty stools.

• Age between other major diarrhea syndromes.

• Villous attenuation.

• In severely affected villi, the coccidia are hard to locate.

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

Significant Diagnostic Tips (cont.)

• When very few coccidia are present, we need to consider other causes of villous atrophy, such as TGE, rotavirus, and Clostridium perfringens Type A or Type C.

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

Acknowledgements

• Histology Technician Mary Horne and the Histology Staff at Rollins Laboratory.

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