A Virulent Babesia bovis Strain Failed to Infect White-Tailed Deer (Odocoileus virginianus)

Abstract

Wildlife are an important component in the vector-host-pathogen triangle of livestock diseases, as they maintain biological vectors that transmit pathogens and can serve as reservoirs for such infectious pathogens. Babesia bovis is a tick-borne pathogen, vectored by cattle fever ticks, Rhipicephalus spp., that can cause up to 90% mortality in naive adult cattle. While cattle are the primary host for cattle fever ticks, wild and exotic ungulates, including white-tailed deer (WTD), are known to be viable alternative hosts. The presence of cattle fever tick populations resistant to acaricides raises concerns regarding the possibility of these alternative hosts introducing tick-borne babesial parasites into areas free of infection. Understanding the B. bovis reservoir competence of these alternative hosts is critical to mitigating the risk of introduction. In this study, we tested the hypothesis that WTD are susceptible to infection with a B. bovis strain lethal to cattle. Two groups of deer were inoculated intravenously with either B. bovis blood stabilate or a larval extract supernatant containing sporozoites from infected R. microplus larvae. The collective data demonstrated that WTD are neither a transient host nor reservoir of B. bovis. This conclusion is supported by the failure of B. bovis to establish an infection in deer regardless of inoculum. Although specific antibody was detected for a short period in the WTD, the PCR results were consistently negative at multiple time points throughout the experiment and blood from WTD that had been exposed to parasite, transferred into naïve recipient susceptible calves, failed to establish infection. In contrast, naïve steers inoculated intravenously with either B. bovis blood stabilate or the larval extract supernatant containing sporozoites rapidly succumbed to disease. These findings provide evidence that WTD are not an epidemiological component in the maintenance of B. bovis infectivity to livestock.

Rhipicephalus appendiculatus ticks transmit Theileria parva from persistently infected cattle in the absence of detectable parasitemia: implications for East Coast fever epidemiology

“…First round reactions were carried out using forward primer Theileria 18S_F1 (5'-GAG GGA GCC TGA GAA ACG-3') and reverse primer Theileria 18S_R1 (5'-GGT ATC TGA TCG TCT TCG ATC C-3') with an annealing temperature of 65 °C. Second round PCR primers were Bab 18S_437-461 F (5'-AAT CCT GAC ACA GGG AGG TAG TGA C-3') and Bab 18S_898-873 R (5'-CTA AGA ATT TCA CCT CTG ACA GT-3') [ 34 ]. The products from three PCR reactions were pooled together and visualized on a Southern dot blot by hybridization with a digoxigenin (DIG)-labeled T. parva probe.…”

Molecular detection and characterization of Theileria spp. infecting cattle in Sennar State, Sudan

“…The reaction was conducted in 32 μl containing 2 μl of extracted genomic DNA, 2.0 mM MgCl 2 , 200 μM dATP, dCTP, dGTP, dTTP, 1.0 μM of each primer set, and 1.3 U of FastStart Taq (Roche, USA). The 18S rRNA inner primers (forward, 5′-AAT CCT GAC ACA GGG AGG TAG TGA C-3′ and reverse, 5’-CTA AGA ATT TCA CCT CTG ACA GT-3′) amplify a fragment of 390 bp (Ueti et al 2015 ). Nested PCR was carried out under the following conditions: 95 °C for 5 min; 35 cycles of 95 °C for 30 s, 65 °C for 30 s, and 72 °C for 30 s; final extension at 72 °C for 5 min.…”

Research on Integrated Management for Cattle Fever Ticks and Bovine Babesiosis in the United States and Mexico: Current Status and Opportunities for Binational Coordination

“…For example, a knowledge gap exists on CFT infestation and the circulation of Babesia pathogens in wildlife and the actual infection rate in Mexican cattle. These aspects are of grave concern for the U.S. [ 29 , 30 ]. In particular, participants in the meeting were most interested in understanding the ecology of R. microplus and R. annulatus in the Texas–Mexico transboundary region, as well as how white-tailed deer, Odocoileus virginianus (Zimmerman) and nilgai, Boselaphus tragocamelus (Pallas) complicate CFT and hemoparasite management efforts.…”

“…ticks and the pathogens they transmit in southern Texas and the transboundary region with Mexico. This introduced wildlife species has been shown to be compatible host for R. microplus together with other tick species of the genus Amblyomma [ 30 ]. This coupled with other studies regarding the movement of nilgai in southern Texas [ 69 , 70 ] highlight the impact of wildlife in the dispersal, control, and eradication of CFT and bovine babesiosis in the U.S. and the transboundary region with Mexico [ 71 ].…”