Sensitivity of Anaplasma marginale genotypes to oxytetracycline assessed by analyzing the msp1α gene in experimentally infected cattle

Primo, María Evangelina; Sarli, Macarena; Thompson, Carolina S.; Torioni, Susana Marta; Echaide, Ignacio

doi:10.1016/j.ttbdis.2021.101787

Cited by 6 publications

(4 citation statements)

References 39 publications

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“…In the present study, after identifying A. marginale we went further on characterizing the msp1a genotypes involved throughout the infection process, providing key information about the dynamics of the transmission. By means of cloning and sequence all msp1a fragments while genotyping, we were able to identify 20 different strains in the IB among the 32 screened clones, emphasizing the importance of this approach for describing the whole range of variants, including the low abundance ones [44,45]. In spite of more than six genotypes per sample have been previously reported in highly prevalent regions [44,46] to our knowledge it is the rst report of such a high number of genotypes within one bovine.…”

Section: Discussionmentioning

confidence: 88%

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Anaplasma marginale multistrain infection in bovines under natural conditions correlates with transovarial transmission and vector competence in Rhipicephalus microplus ticks

Fourniere

Guillemi

Paoletta

et al. 2022

Preprint

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Background Anaplasma marginale, a gram-negative obligate intracellular microorganism, infects erythrocytes of ruminants and other host species from tropical and subtropical world regions. This pathogen of importance for cattle production, is known to be transmitted mechanically and through hematophagous parasites, mainly by Rhipicephalus microplus ticks. Even though transovarial transmission of A. marginale has been previously reported in R. microplus ticks, there is no evidence of A. marginale transmission from the resulting unfed larvae to a susceptible host. The aim of the present study was to evaluate the transovarial transmission of A. marginale in the R. microplus tick under natural conditions and to study the vector competence of the infected hatched larvae. Methods Engorged female R. microplus ticks were sampled from A. marginale positive bovines from an enzootic area in Argentina, and larvae were obtained from a subgroup of these females. After identifying A. marginale in the females and their larvae, selected ticks collected from a single bovine were used. After spawn, hatched larvae were seeded on a susceptible healthy bovine and another subgroup of engorged R. microplus ticks were subjected to dissection to recover the salivary glands and ovaries for A. marginale identification. Anaplasma marginale was detected by PCR and molecularly characterized by means of cloning and sequence all msp1α fragments while genotyping. Results A. marginale was detected in naturally infected bovines, in different organs of engorged R. microplus females that were parasitizing them, and in the larvae obtained from these females. A. marginale infection of the susceptible bovine was corroborated both from DNA detection and from compatible structures in a blood smear. The characterization of A. marginale msp1α genotypes involved throughout the infection process provided relevant information about the dynamics of the transmission process. Conclusions The results demonstrate the transovarial transmission of A. marginale in R. microplus ticks under natural conditions and, through an experimental infection assay, the vector competence of the infected R. microplus larvae to transmit A. marginale to a susceptible bovine. The high genetic diversity of A. marginale in natural transmission settings seems to be one of the key factors for the transovarial transmission to occur.

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Section: Discussionmentioning

confidence: 88%

“…Thus, the mismatch among the genotypes of larvae (L) and the susceptible bovine (SB) could be due to low coverage of larvae genotype richness. On the other hand, we could have missed some low abundance strains while genotyping the susceptible bovine [45].…”

Section: Discussionmentioning

confidence: 99%

Anaplasma marginale multistrain infection in bovines under natural conditions correlates with transovarial transmission and vector competence in Rhipicephalus microplus ticks

Fourniere

Guillemi

Paoletta

et al. 2022

Preprint

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“…Cattle affected with any clinical form of anaplasmosis may recover when antibiotics are administered promptly. Yet, the pathogen may not be completely eliminated; thus, some cattle may be lifelong carriers ( 5 , 6 ), acting as reservoirs for susceptible or healthy animals under inappropriate veterinary practices ( 7 ).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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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.

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“…Therefore, in our study, cattle with nPCR-negative and dasELISA-positive results could be explained by the elimination or reduction of parasitemia, either naturally (cycles of parasitemia) or through the administration of antibiotics. 14,15 We did not explore these aspects because we did not know if the cattle had been treated with antibiotics nor did we know the time elapsed between infection and sampling.…”

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confidence: 99%

Development and field evaluation of an ELISA to differentiate Anaplasma marginale–infected from A. centrale–vaccinated cattle

et al. 2023

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Immunization of calves with Anaplasma centrale is used to prevent acute anaplasmosis caused by A. marginale. Natural and vaccine-acquired immunity is detected through serologic tests based primarily on A. marginale recombinant major surface protein 5 (MSP5m) because it has 91% identity with MSP5 from A. centrale (MSP5c). We developed a displacement, double-antigen, sandwich ELISA (ddasELISA) to detect antibodies against A. marginale or A. centrale. For ddasELISA validation, we analyzed serum samples positive for antibodies against Anaplasma spp. from cattle naturally infected with A. marginale ( n = 300) or vaccinated with A. centrale ( n = 255). Species-specific nested PCR (nPCR) assays were used to confirm infection. The optical density (OD) values obtained from antibodies directed at unique epitopes of A. marginale (ODAm) or A. centrale (ODAc) were used in the formula ODAm/ODAc. If the derived ratio was > 0.38, the serum sample was considered positive for antibodies against A. marginale, with 98.9% sensitivity and 98.0% specificity. In a field evaluation, we analyzed 702 Anaplasma spp. antibody–positive serum samples from 34 herds by ddasELISA and nPCR; 571 were classified by ddasELISA as A. marginale–infected or A. centrale–vaccinated, with 84% agreement (κ = 0.70) between ddasELISA and nPCR. Our results indicate that ddasELISA could be used as a cost-effective alternative to molecular techniques to confirm infection with A. marginale in countries in which prevention is based on vaccination with A. centrale.

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Sensitivity of Anaplasma marginale genotypes to oxytetracycline assessed by analyzing the msp1α gene in experimentally infected cattle

Cited by 6 publications

References 39 publications

Anaplasma marginale multistrain infection in bovines under natural conditions correlates with transovarial transmission and vector competence in Rhipicephalus microplus ticks

Anaplasma marginale multistrain infection in bovines under natural conditions correlates with transovarial transmission and vector competence in Rhipicephalus microplus ticks

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

Development and field evaluation of an ELISA to differentiate Anaplasma marginale–infected from A. centrale–vaccinated cattle

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