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Research Summary - 4

Prevalence of 'Mycoplasma wenyonii' and Candidatus Mycoplasma haemobos in Wisconsin and Michigan dairy cattle herds

Date/Time: 9/14/2019    11:15
Author: Rachel  Schambow
Clinic: University of WI-School of Veterinary Medicine
City, State, ZIP: Madison, WI  53705

Prevalence of 'Mycoplasma wenyonii' and Candidatus Mycoplasma haemobos in Wisconsin and Michigan dairy cattle herds

R.A. Schambow, BS 1 ; K. Poulsen , DVM, PhD, DACVIM 2 ; S. Bolin, DVM, MS, PhD 3 ; D. Krahn, DVM 5 ; B. Norby, DVM, MPVM, PhD 4 ; D. Sockett, DVM, PhD, DACVIM 2 ;
1University of Wisconsin School of Veterinary Medicine, 2015 Linden Dr, Madison, WI 53706
2Wisconsin Veterinary Diagnostic Lab, 445 Easterday Ln, Madison, WI 53706
3Michigan State University, College of Veterinary Medicine, Veterinary Diagnostic Laboratory, 4125 Beaumont Rd, Lansing, MI 48910
4Michigan State University, Dept. Large Animal Clinical Sciences, 786 Wilson Rd, East Lansing, MI 48824
5Country Hills Animal Health, W4893 Mill Road, Fond du Lac, WI 54937
6Michigan State University, Dept. of Animal Science, Anthony Hall, 474 S. Shaw Lane, East Lansing, MI 48824


Mycoplasma wenyonii (fmr. Eperythrozoon wenyonii) is a hemotrophic, epicellular bacterial parasite of cattle and is associated with clinical disorders including hemolytic anemia, decreased milk yield, and scrotal, teat, and hindlimb edema. M. wenyonii and related organism, Candidatus Mycoplasma haemobos have been found in apparently healthy cattle in other countries, but little is known about their prevalence in the U.S. The objective of this prospective, cross-sectional study was to determine herd-level prevalence of M. wenyonii and C.M. haemobos in dairy cattle located in WI and MI.

Materials and Methods:

Researchers visited randomly recruited farms and collected blood samples from 30 lactating cows. PCR tests were used for M. wenyonii, C.M. haemobos, and ELISA was used to test for bovine leukosis virus (BLV). Blood samples were collected from cows located in 64 WI herds (n = 1929 samples) and 18 MI herds (n = 591 samples).


At least 1 BLV positive sample was found in 83% (95% CI: 71.3%-91.1%) of WI herds and 100% (one-sided 97.5% CI: 81.5%-100%) of MI herds. At least 1 blood sample from all herds in both MI and WI, tested positive for M. wenyonii and CM Haemobos. Within herd prevalence did not vary among states and were 77.3% (95% CI: 75.6%-78.9%), 71.6% (95% CI: 69.8%-73.4%) and 39.8%% (95% CI: 37.9%-1.8%) for C.M. haemobos, M. wenyonii and BLV, respectively. Across states, 22.1% (95% CI: 20.5%-23.8%) of cows were positive for all 3 organisms. Parity was recorded for 546 cows. The prevalence of positive cows by parity (1,2, 3, 4+) were 89.8% (84.6-93.8), 76.8% (69.3-83.2), 78.4% (68.8-86.1) and 73.8% (64.4-81.9) for C.M. haemobos; 70.6% (63.5-77.0) , 57.4% (49.2-65.3), 53.6% (43.2-63.8) and 43.9% (34.3-53.9) for M. wenyonii and 26.2% (20.1-33.1) , 32.3% (25.0-40.2) , 58.8 (48.3-68.7) and 44.9% (35.2-54.8) for BLV.


This is the first report of prevalence of these hemotropic mycoplasmas in Wisconsin and Michigan, both of which appear to be high. The extent of their effect on cattle health and productivity remains unknown and warrants further study.

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