Case Series: Death losses due to Yersinia pseudotuberculosis Infections in Cattle, South Dakota, Fall 2019
By: Russ Daly, DVM, MS, DACVPM, Professor/Extension Veterinarian; Dale Miskimins, DVM, MS, Professor - Veterinary and Biomedical Sciences Department, South Dakota State University
Several cases of diarrhea and death in cows and calves were identified by veterinarians across east central South Dakota during late fall, 2019. Examination of tissues submitted to the South Dakota Animal Disease Research and Diagnostic Laboratory (ADRDL) revealed lesions and culture results compatible with Yersinia pseudotuberculosis infections.
Yersinia pseudotuberculosis is a gram-negative bacteria reported to infect a wide variety of animal hosts, including cattle, sheep, goats, deer, dogs and cats. It’s also considered zoonotic, with the potential to cause signs of digestive illness in people, usually through contaminated food or water, although reports of human illness are rare.1
Sporadic cases of Y. pseudotuberculosis have been reported in cattle, particularly in Australia.2,3 Enterocolitis, resulting in diarrhea and death, is the most common syndrome reported, but pneumonia, mastitis and abortion has also been identified. Infection of the small and large intestine has been the most common presentation in the cases noted at the ADRDL:
Case 1. Submitted to the ADRDL on Nov. 7, 2019. A 100-cow herd from Beadle County experienced three dead cows, aged approximately 2 ½ years of age. These cows were still on pasture with calves at side, being fed a total mixed ration on pasture. These previously-healthy cows experienced rapid weight loss and diarrhea, with a course of disease lasting a few days before dying. At the time of submission, four other cows had similar clinical signs.
The veterinarian noted inflamed intestines and inflamed, enlarged mesenteric lymph nodes on necropsy of 2 of the cows. A slight degree of pneumonia was noted in the lungs. The main differential diagnoses were salmonellosis and Johne’s Disease.
At the ADRDL, pathologists found multifocal ulcerative enterocolitis with numerous bacterial colonies in the lesions. Mesenteric lymph nodes were infiltrated with increased numbers of macrophages. There was also some patchy fibrinocellular pneumonia noted. Yersinia pseudotuberculosis was cultured from the intestine, while Mannheimia hemolytica and Pasteurella multocida were found in the patchy lung lesions. The antimicrobial sensitivity test revealed the germ sensitive to ampicillin, ceftiofur, danofloxacin, enrofloxacin, florfenicol, gentamicin, neomycin, spectinomycin, sulfadimethoxine and tetracycline.
Prior to sensitivity results, the veterinarian treated the clinically affected cows with ceftiofur, noting a good response. Feed grade tetracycline was administered to the group for the pneumonia for five days, and no further cases were noted. The veterinarians advised the client to isolate the calves nursing the affected cows from the other weaned calves when weaning eventually took place. No illness was noted in the calves in this affected cow group, but overall, body condition was poorer in this group compared to other cow groups.
Case 2. Submitted to the ADRDL on Nov. 18, 2019. The submission originated from a group of 200 8-month old Holstein heifers in an open lot, in Minnehaha County. At the time, 13 calves had died from the group, with twp calves remaining clinically affected. Death losses in this group began with five to six calves with chronic pneumonia; at the time of submission, “good” calves were being lost. Clinically affected calves showed low-grade fevers, diarrhea, were off feed, and died after a short course of illness (one to two days).
Observations from the veterinarian performing the necropsy included dilated intestines with sparse fluid content and a thickened abomasal lining containing areas of clear fluid protruding into the lumen. Pathologists at the ADRDL found multifocal enteritis in the jejunum, again with high numbers of bacteria associated with the lesions, as well as abomasal edema and lymphadenitis. Yersinia pseudotuberculosis was cultured from the jejunum; the isolate was sensitive to ampicillin, ceftiofur, danofloxacin, enrofloxacin, gentamicin, neomycin and spectinomycin. Additional culture results included Bibersteinia trehalosi and hemolytic E. coli from intestine.
Case 3. Submitted to the ADRDL on Nov. 20, 2019 from Moody County. Affected animals in this case were also Holstein calves, four months of age, weaned and on a total mixed ration when moved into a barn with a bedded pack. Eight calves had died from a group of 60, with eight additional calves clinically affected at the time of submission. Diarrhea was the predominant clinical sign in these calves, affecting previously healthy animals with a short course of illness prior to death. Bacterial respiratory disease was also present in this group of calves; some sick calves had previously responded to treatment for respiratory disease with tildipirosin. The veterinarian noted that the bedding pack had been exceedingly wet and in need of cleaning; a group of calves on the same pack two months prior had gone through the same clinical signs, with four to five calves lost from a group of 30.
On necropsy, the veterinarian found watery intestinal contents and enlarged lymph nodes and suspected salmonellosis. At the ADRDL, pathologists found multifocal suppurative and necrotizing enteritis with bacteria in the lesions. Yersinia pseudotuberculosis was cultured from intestine and was sensitive to ceftiofur, danofloxacin, enrofloxacin, gentamicin, neomycin and sulfadimethoxine. Other findings included Bibersteinia trehalosi cultured from the liver.
Discussion
The seasonality of these cases corresponded with that of cases in a report that described Yersinia pseudotuberculosis cases in 17 different herds in Australia in the 1980s.2 Cases there occurred during the winter and early spring, and primarily in adult cattle grazing pastures affected by flooding or heavy rain. In the three South Dakota cases, wet and cool conditions were present – whether on flooded pasture, wet open lots, or wet bedded pack. The Australian authors speculated that the association with wet conditions and low temperatures favors the survival and transmission of Y. pseudotuberculosis.
Each of the three South Dakota cases exhibited evidence of co-morbidities – in particular pneumonia. Since Y. pseudotuberculosis is apparently widely distributed in the environments of cattle, it’s possible that in these cases, stress on the immune system from other infections (and possibly increased exposure) could have resulted in opportunistic infections.
The main differential diagnosis for these cases was salmonellosis. The presence of diarrhea, fever, and sudden death is also characteristic of infection with Salmonella spp., as well as the presence of inflamed intestinal mucosa and enlarged mesenteric lymph nodes. In these cases, Salmonella spp. was not identified. Culture of Y. pseudotuberculosis requires specialized bacteriologic techniques and must be specifically requested from the pathologist or the submitting veterinarian. In cows, Johne’s Disease is a differential; however the sudden death noted in these cases would tend to differentiate it from the more chronic Johne’s Disease.
Veterinarians reported good success treating clinically affected animals with antibiotics. The antibiogram varied somewhat across isolates, but all three cases had isolates with sensitivity to ceftiofur, danofloxacin, enrofloxacin, gentamicin, and neomycin.* Sensitivity to antibiotics such as gamithromycin, tildipirosin and tulathromycin could not be determined.
Yersinia pseudotuberculosis is considered a zoonotic agent, with the potential to cause acute gastroenteritis, fever, and abdominal pain. Human cases are apparently rare, but may be under-identified by health professionals and laboratories. Veterinarians should raise this possibility with their clients and encourage the use of sufficient personal protective practices (as well as use them themselves).
The advent of wet pastures and lots, combined with cooler temperatures, may be favoring the multiplication of Y. pseudotuberculosis at the expense of other enteric pathogens in the environment. Additionally, animals affected by the lingering effects of stressful summer and fall conditions may be particularly susceptible to this germ’s effect. Veterinarians should be aware of this disease and include it on their list of differentials for diarrhea and rapid death loss when the conditions suggest it.
* Antimicrobial susceptibility information does not represent a treatment recommendation. Veterinarians treating animals have the responsibility for recommending therapy within regulatory and professional guidelines, and for providing information on withholding and/or withdrawal times for market consumption.
References
- Long, C., Jones, T. F., Vugia, D. J., et. al. (2010). Yersinia pseudotuberculosis and Y. enterocolitica Infections, FoodNet, 1996–2007. Emerging Infectious Diseases, 16(3), 566-567. https://dx.doi.org/10.3201/eid1603.091106
- Callinan, R. B., Cook, R. W., Boulton, J. G. et al. (1988). Enterocolitis in cattle associated with Yersinia pseudotuberculosis infection. Aust Vet J, 65(1): 8-11.
- Slee, K. J., Brightling P., Seiler, R. J. (1988). Enteritis in cattle due to Yersinia pseudotuberculosis infection. Aust Vet J, 65(9):271-5.