Investigation into the role of potentially contaminated feed as a source of the first-detected outbreaks of porcine epidemic diarrhea in Canada.

In January 2014, approximately 9 months following the initial detection of porcine epidemic diarrhea (PED) in the USA, the first case of PED was confirmed in a swine herd in south-western Ontario. A follow-up epidemiological investigation carried out on the initial and 10 subsequent Ontario PED cases pointed to feed as a common risk factor. As a result, several lots of feed and spray-dried porcine plasma (SDPP) used as a feed supplement were tested for the presence of PEDV genome by real-time RT-PCR assay. Several of these tested positive, supporting the notion that contaminated feed may have been responsible for the introduction of PEDV into Canada. These findings led us to conduct a bioassay experiment in which three PEDV-positive SDPP samples (from a single lot) and two PEDV-positive feed samples supplemented with this SDPP were used to orally inoculate 3-week-old piglets. Although the feed-inoculated piglets did not show any significant excretion of PEDV, the SDPP-inoculated piglets shed PEDV at a relatively high level for ≥9 days. Despite the fact that the tested PEDV genome positive feed did not result in obvious piglet infection in our bioassay experiment, contaminated feed cannot be ruled out as a likely source of this introduction in the field where many other variables may play a contributing role.

Mycobacterium avium subsp. paratuberculosis in muscle, lymphatic and organ tissues from cows with advanced Johne's disease.

Blood, liver, kidney, lymph nodes and muscle tissue were obtained from the carcasses of five cows with advanced Johne's disease. Samples from the raw tissues, from cooked muscle tissues and from cooked hamburger patties that contained chopped mesenteric lymph nodes were collected aseptically. Each sample was divided into two portions, one of which was decontaminated. Both portions were homogenized. Homogenates were spread on selective agar for the recovery of Mycobacterium avium subsp. paratuberculosis (Map) and inoculated into a Map growth medium with the organism being detected in the cultures by PCR procedures and Ziehl-Neelsen staining. Map were recovered at numbers > 10(3) cfu/g from 7 of 15 liver and mesenteric and ileocaecal lymph node samples; and at lesser numbers from 5 of 15 kidney and superficial inguinal and prescapular lymph node samples. The numbers recovered from decontaminated and not decontaminated portions of each sample were generally similar. Map was recovered from 1 and detected in 6 of 50 not decontaminated portions of samples of raw, chilled or frozen meat; and detected in 1 of 15 not decontaminated samples of meat cooked to 61 degrees C, and in 1 of 40 samples of meat cooked to >/=70 degrees C. Map was detected in 2 of 4 samples of mesenteric lymph nodes cooked to 61 degrees C, but not in samples cooked to > or =70 degrees C. The findings indicate that Map may be present in meat from infected animals at low numbers, but that any such organisms are likely to be inactivated when meat is cooked to a well done condition.

Segmental aplasia of the left paramesonephric duct in the cow.

Segmental aplasia of the left uterine horn in a multiparous Holstein cow was diagnosed by palpation and ultrasonography. Treatment with prostaglandin was unsuccessful in eliminating the fluid from the distended uterine horn. Segmental aplasia should be included in the list of differential diagnoses for cows with nonresponsive uterine enlargement.