Control of tick infestations and pathogen prevalence in cattle and sheep farms vaccinated with the recombinant Subolesin-Major Surface Protein 1a chimeric antigen

Abstract

BackgroundDespite the use of chemical acaricides, tick infestations continue to affect animal health and production worldwide. Tick vaccines have been proposed as a cost-effective and environmentally friendly alternative for tick control. Vaccination with the candidate tick protective antigen, Subolesin (SUB), has been shown experimentally to be effective in controlling vector infestations and pathogen infection. Furthermore, Escherichia coli membranes containing the chimeric antigen composed of SUB fused to Anaplasma marginale Major Surface Protein 1a (MSP1a) (SUB-MSP1a) were produced using a simple low-cost process and proved to be effective for the control of cattle tick, Rhipicephalus (Boophilus) microplus and R. annulatus infestations in pen trials. In this research, field trials were conducted to characterize the effect of vaccination with SUB-MSP1a on tick infestations and the prevalence of tick-borne pathogens in a randomized controlled prospective study.MethodsTwo cattle and two sheep farms with similar geographical locations and production characteristics were randomly assigned to control and vaccinated groups. Ticks were collected, counted, weighed and classified and the prevalence of tick-borne pathogens at the DNA and serological levels were followed for one year prior to and 9 months after vaccination.ResultsBoth cattle and sheep developed antibodies against SUB in response to vaccination. The main effect of the vaccine in cattle was the 8-fold reduction in the percent of infested animals while vaccination in sheep reduced tick infestations by 63%. Female tick weight was 32-55% lower in ticks collected from both vaccinated cattle and sheep when compared to controls. The seroprevalence of Babesia bigemina was lower by 30% in vaccinated cattle, suggesting a possible role for the vaccine in decreasing the prevalence of this tick-borne pathogen. The effect of the vaccine in reducing the frequency of one A. marginale msp4 genotype probably reflected the reduction in the prevalence of a tick-transmitted strain as a result of the reduction in the percent of tick-infested cattle.ConclusionsThese data provide evidence of the dual effect of a SUB-based vaccine for controlling tick infestations and pathogen infection/transmission and provide additional support for the use of the SUB-MSP1a vaccine for tick control in cattle and sheep.

Control of Lyme borreliosis and other Ixodes ricinus-borne diseases

“…Anti-tick vaccines targeting other tick species already exist and are being used in the veterinary field. The strategy behind these vaccines is to locally control Rhipicephalus ( Boophilus ) tick species, and act as a safe and environmentally friendly alternative to acaricides [ 214 , 215 ]. Application of anti-tick vaccines was shown to dramatically decrease the incidence of bovine babesiosis [ 216 ].…”

Identification of protective linear B-cell epitopes on the subolesin/akirin orthologues of Ornithodoros spp. soft ticks

“…One of such antigens is the so-called subolesin protein, initially discovered as a protective antigen in Ixodes scapularis [16] and subjected to intensive investigation since then [13,15,[17][18][19][20]. Subolesin gene and protein sequences are highly conserved in ticks and are the orthologues of insect and vertebrate akirins, which are evolutionarily conserved proteins that function as transcription factors in the regulation of gene expression.…”

Fine-scale spatial and temporal heterogeneities in insecticide resistance profiles of the malaria vector, Anopheles arabiensis in rural south-eastern Tanzania

“…4. Discussion: One paper that would be useful to Cite is the Ochomo et al 2014 paper which describes heterogeneity of insecticide resistance in Kenya 1 .…”