Bovine anaplasmosis transmission studies conducted under controlled natural exposure in a Dermacentor andersoni = (venustus) indigenous area of eastern Oregon
Peterson, K.J.; Raleigh, R.J.; Stroud, R.K.; Goulding, R.L.
American Journal of Veterinary Research 38(3): 351-354
1977
ISSN/ISBN: 0002-9645 PMID: 557939 Document Number: 121440
In Anaplasma marginale transmission studies conducted on the high semi-arid range of eastern Oregon during the 1974 and 1975 vector season, A marginale-susceptible calves (principals) were maintained on 2 raised tick-proof platforms. Anaplasmosis-susceptible control calves of approximately the same age and latent-infected cows grazed the area surrounding the platforms. One latent-infected steer spent the entire 1975 vector season on a platform with the principals. The 28 principals did not develop anaplasmosis, whereas 15 of 30 (50%) controls became infected. The disease was not transmitted from the latent-infected cattle to the principals exposed only to flying hematophagous insects, whereas 50% of the controls exposed to the Rocky Mountain wood tick Dermacentor andersoni) = (venustus) developed the disease. Dermacentor andersoni appears to be the principal vector on this range.