In order to understand the genetic diversity of A. marginale, several efforts have been made around the world. This rickettsia affects a significant number of ruminants, causing bovine anaplasmosis, so the interest in its virulence and how it is transmitted have drawn interest not only from a molecular point of view but also, recently, some genomics research have been performed to elucidate genes and proteins with potential as antigens. Unfortunately, so far, we still do not have a recombinant anaplasmosis vaccine. In this review, we present a landscape of the multiple approaches carried out from the genomic perspective to generate valuable information that could be used in a holistic way to finally develop an anaplasmosis vaccine. These approaches include the analysis of the genetic diversity of A. marginale and how this affects control measures for the disease. Anaplasmosis vaccine development is also reviewed from the conventional vaccinomics to genome-base vaccinology approach based on proteomics, metabolomics, and transcriptomics analyses reported. The use of these new omics approaches will undoubtedly reveal new targets of interest in the near future, comprising information of potential antigens and the immunogenic effect of A. marginale proteins.

We present here the draft genome sequence of the first “Candidatus Mycoplasma haemobos” strain found in cattle in Mexico. This hemotropic mycoplasma causes acute and chronic disease in animals. This genome is a starting point for studying the role of this mycoplasma in coinfections and synergistic mechanisms associated with the disease.

The current description of biological transmission of Anaplasma marginale by Rhipicephalus microplus ticks, includes of the biological intrastadial and transstadial transmission. Both transovarian transmission of Anaplasma from engorged ticks to their progeny and, transmission from infected unfed larvae to the mammalian host is controversial. In order to demonstrate vertical transmission of A. marginale by R. microplus ticks under experimental conditions, feed-acquisition infected engorged females were incubated at 18 °C or 28 °C for oviposition. Larvae hatched from these ticks were used to infest two steers for each incubation temperature. None of the four steers infested with either lot of larvae developed clinical disease, yet subclinical infection was observed in the steers infested with larvae from engorged ticks incubated at 28 °C for hatching. gDNA from, larvae used for the infection of the carrier tick donor, gDNA from larvae oviposited at 28 ºC, gDNA from blood of A. marginale-positive steers, were positive for amplification of msp5 and msp1α the variable region by PCR. All other DNA samples from the original stabilate, blood from the donor steer, larvae from ticks incubated at 28 °C and blood from steers infested with these same larvae were positive to both, msp5 and msp1α PCR. msp1α sequences of all PCR products were the same and are consistent with previously reported Tlapacoyan-2 sequence. The present evidence indicates that R. microplus is capable of passing A. marginale to its progeny and that these infected larvae can transmit the infection to susceptible hosts.

Omics sciences and new technologies to sequence full genomes provide valuable data that are revealed only after detailed bioinformatic analysis is performed. In this work, we analyzed the genomes of seven Mexican Anaplasma marginale strains and the data from a transcriptome analysis of the tick Rhipicephalus microplus. The aim of this analysis was to identify protein sequences with predicted features to be used as potential targets to control the bacteria or tick-vector transmission. We chose three amino acid sequences different to all proteins previously reported in A. marginale that have been used as potential vaccine candidates, and also, we report, for the first time, the presence of a peroxinectin protein sequence in the transcriptome of R. microplus, a protein associated with the immune response of ticks. The bioinformatics analyses revealed the presence of B-cell epitopes in all the amino acid sequences chosen, which opens the way for their likely use as single or arranged peptides to develop new strategies for the control and prevention of bovine anaplasmosis transmitted by ticks.