Selected zoonotic pathogens and diseases from Ontario identified at the AHL in 2021

Tanya Rossi, Đurđa Slavić, Davor Ojkic

 Animal Health Laboratory, University of Guelph, Guelph, ON                       

 AHL Newsletter 2022;26(1):6.

As the current pandemic highlights, emerging, and re-emerging human infectious diseases often originate or persist in animal reservoirs.  The AHL plays an important role in surveillance of zoonotic pathogens in many domestic and wild animals by annually reporting case counts (Tables 1, 2).

The percentage of animals identified as positive for leptospirosis was roughly unchanged in 2021 in all species except equines, where there was a moderate decrease in cases.  The total number of submissions tested was approximately the same as 2020 in all species.  These data do not take into account vaccination status, as many species may have previously been vaccinated for leptospirosis.

The discrepancy between Brucella canis cases between 2020 and 2021 (Table 1) can be explain by a change in tests used (in 2020 only 2ME-RSAT positive cases were included).  There was a moderate increase in MRSP, and all Strep spp. included in this report.  Equine eastern encephalitis virus cases also increased, although overall numbers remain low.  These data are case counts from AHL submissions and subject to laboratory submission biases.  Therefore, results may not represent the whole picture of zoonotic diseases in Ontario and should not be used to calculate population prevalence estimates.  Monitoring programs are not included.   AHL

Table 1. Number of cases with selected zoonotic pathogens isolated and/or identified at the AHL in 2021.

Agent Bovine Swine Equine Ovine Caprine Chicken Turkey Canine Feline Other 2021 2020
Ascarids (incl T. canis, T. cati, T. leonina, Baylisascaris sp.)     6     71   18   5 100 93
Blastomyces dermatitidis               5     5 7
Bordetella bronchiseptica 2 47 5 1       3   5 63 51
Borrelia burgdorferi (Lyme disease), serology     25         11     36 34
Brucella sp. (non-abortus)               131     131 14
Campylobacter coli/ jejuni/ fetus subsp. fetus 2     4       3     9 7
Chlamydia sp.   2   9 11           22 19
Clostridium difficile     1   1           2 3
Coxiella burnetii (Q fever) 9     26 21           56 45
Cryptococcus sp.                     0 0
Cryptosporidium sp. 178     2 7       3 11 201 239
Eastern equine encephalitis virus     8               8 4
Echinococcus multilocularis               2     2 2
Giardia sp. 8             22 1   31 35
Listeria monocytogenes 8 1   5 4     1 2   21 25
Methicillin-resistant Staph aureus (MRSA)   1 1         2   1 5 6
Methicillin-resistant S. pseudintermedius (MRSP)               87 2 1 90 62
Rabies virus                   4 4 5
Salmonella enterica 56 78 4 4   29 54 2   18 245 245
Streptococcus suis 1 176 1 1   6 1       186 148
Streptococcus equisimilis 1 45 14   1     3     64 48
Streptococcus zooepidemicus 2 3 155   2     4 1 1 168 140
Toxoplasma sp       13 3       2   18 15
Verotoxigenic E. coli (VTEC) 3 3                 6 6
West Nile virus     3             11 14 27
Yersinia enterocolitica 1 1           2     4 5
Total                     1491 1285

Table 2. Leptospira spp. seropositive, IHC-positive, or PCR-positive cases identified at the AHL in 2021.

Leptospira spp. serovar Bovine Swine Equine Canine Other
L. autumnalis 26 4 25 79 1
L. brattislava 19 4 21 48 1
L. canicola 26 2 13 46 1
L. grippotyphosa 9 1 4 43 1
L. hardjo 32 1 7 17 1
L. icterohaemorrhagiae 30 4 15 65 1
L. pomona 34 4 13 68 1
IHC or PCR-positive 0 0 1 7 0
Positive/tested cases 54/173 4/28 35/65 115/199 1/2