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United States Department of Agriculture

Agricultural Research Service


item Futse, James
item Ueti, Massaro
item Knowles, Donald - Don
item Palmer, Guy

Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2003
Publication Date: 8/20/2003
Citation: Futse, J.E., Ueti, M.W., Knowles, D.P., Palmer, G.H. Transmission of Anaplasma marginale by Boophilus microplus: Retention of Vector competence in the absence of Vector-pathogen interaction. Journal of Clinical Microbiology. 2003. v. 41(8). p. 3829-3834.

Interpretive Summary: A major issue for the transmission of tick-borne diseases is the relationship between strains of the organism and genus and species of tick capable of transmission. The data of this manuscript show that regardless of the distance (time and space) between strains of A. marginale and two tick species, the ability to transmit is maintained. This is important from the standpoint of foreign strains of A. marginale and the potential reintroduction of the tick Boophilus microplus into the U. S. due to acaracide resistance.

Technical Abstract: Whether arthropod vectors retain competence for transmission of infectious agents in the long-term absence of vector-pathogen interaction is unknown. We addressed this question by quantifying the vector competence of two tick vectors, with mutually exclusive tropical- versus temperate-region distributions, for genetically distinct tropical- and temperate-region strains of the cattle pathogen Anaplasma marginale. The tropical cattle tick Boophilus microplus, which has been eradicated from the continental United States for over 60 years, was able to acquire and transmit the temperate St. Manes (Idaho) strain of A. marginate. Similarly, the temperate- region tick Dermacentor andersoni efficiently acquired and transmitted the Puerto Rico strain of A. marginate. There were no significant quantitative differences in infection rate or number of organisms per tick following feeding on cattle with persistent infections of either A. marginate strain. In contrast, the significantly enhanced replication of the Puerto Rico strain in the salivary gland of B. micro plus at the time of transmission feeding is consistent with adaptation of a pathogen strain to its available vector. However, the transmission of both strains by B. microplus demonstrates that adaptation or continual interaction between the pathogen and vector is not required for retention of vector competence. Importantly, the results clearly show that reestablishment of acaricide-resistant B. microplus in the United States would be associated with A. marginate transmission.

Last Modified: 06/24/2017
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