Anaplasma marginale Yucatan (Mexico) Strain. Assessment of low virulence and potential use as a live vaccine

Bovine Anaplasmosis: Will there ever be an almighty effective vaccine?

Bovine anaplasmosis is a tick-borne bacterial disease with a worldwide distribution and the cause of severe economic losses in the livestock industry in many countries, including México. In the present work, we first review the elements of the immune response of the bovine, which allows ameliorating the clinical signs while eliminating the majority of the blood forms and generating an immunologic memory such that future confrontations with the pathogen will not end in disease. On the other hand, many vaccine candidates have been evaluated for the control of bovine anaplasmosis yet without no commercial worldwide effective vaccine. Lastly, the diversity of the pathogen and how this diversity has impaired the many efforts to control the disease are reviewed.

Immunoinformatic Analysis to Identify Proteins to Be Used as Potential Targets to Control Bovine Anaplasmosis

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.

Draft Genome Sequences of Anaplasma marginale Strains MEX-15-099-01 and MEX-31-096-01, Two Mexican Isolates with Different Degrees of Virulence

Anaplasma marginale is an intraerythrocytic bacterium that causes bovine anaplasmosis and is endemic in Mexico. In this work, we report two draft genome sequences of Mexican isolates from different geographical regions and with different degrees of virulence.

Anaplasma marginale is an intraerythrocytic bacterium that causes bovine anaplasmosis and is endemic in Mexico. In this work, we report two draft genome sequences of Mexican isolates from different geographical regions and with different degrees of virulence.

Anaplasma marginale: Diversity, Virulence, and Vaccine Landscape through a Genomics Approach

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.

Multistrain genome analysis identifies candidate vaccine antigens of Anaplasma marginale

Anaplasmosis in domestic livestock is an impediment to animal health and production worldwide, especially in developing countries in Africa, Asia, and South America. Vaccines have been developed and marketed against the causative organism, Anaplasma marginale; however, these have not been widely used because of breakthrough infections caused by heterologous strains and because of the risk of disease induced by live vaccine strains themselves. Recently, molecular studies have enabled progress to be made in understanding the causes for breakthrough infections and in defining new vaccine targets. A. marginale has a system for antigenic variation of the MSP2 and MSP3 outer membrane proteins which are members of the pfam01617 gene superfamily. In this study, we used high throughput genome sequencing to define conservation of different superfamily members in ten U.S. strains of A. marginale and also in the related live vaccine strain A. marginale subspecies centrale. The comparisons included the pseudogenes that contribute to antigenic variation and other superfamily-encoded outer membrane proteins. Additionally, we examined conservation of other proteins proposed previously as vaccine candidates. These data showed significantly increased numbers of SNPs in A. marginale subspecies centrale when compared to all U.S. A. marginale strains. We defined a catalog of 19 conserved candidate vaccine antigens that may be suitable for development of a multi-component recombinant vaccine. The methods described are rapid and may be suitable for other prokaryotes where repeats comprise a substantial portion of their genomes.

Molecular epidemiology of bovine anaplasmosis with a particular focus in Mexico

Bovine anaplasmosis, caused by the rickettsia Anaplasma marginale, has a worldwide distribution and is the cause of great economic losses in developing countries where it is highly endemic. Transmission is carried mainly by ixodid ticks: Dermacentor spp. and Rhipicephalus (Boophilus) spp. Mechanical transmission is important in disseminating the disease within and across herds. The relationship between the rickettsia, the host and the vector is complex. Several surface proteins (Msps) have been described with functions that span from adhesins towards the erythrocyte and tick cells to evasion of the immune system of the host through the generation of antigenic variants. Biologic transmission of A. marginale through Dermacentor ticks has been well studied but many questions are unresolved as to how this organism spreads within and across herds and little is known about the role Rhipicephalus (Boophilus) ticks play in transmission in the Americas. Mechanical transmission in the absence of ticks and lack of transmission through ticks are questions that need to be addressed. Phylogenetic studies of the rickettsia show wide antigenic and genetic mosaics which affects the design of new vaccines. In the present work we will discuss the molecular elements in the relationship between the rickettsia, the tick and the mammalian host associated to the distribution and persistence of the pathogen in nature.