Closing the Gaps to Understand the Tick Transmission of Anaplasma marginale among Giant Anteaters (Myrmecophaga tridactyla) in Argentina

Abstract

Anaplasma marginale, a well-known cattle pathogen of tropical and subtropical world regions, has been previously molecularly characterized in a giant anteater (Myrmecophaga tridactyla) from Corrientes, Argentina. Ticks or other hematophagous arthropod involved in the wild transmission cycle remained unknown. The aim of the present study was to analyze the simultaneous occurrence of A. marginale in blood samples and ticks from giant anteaters from Corrientes in order to investigate if ticks could be relevant in the transmission among these mammals. Blood samples from 50 giant anteaters collected in different years and 26 ticks Amblyomma dubitatum and A. sculptum were studied through the molecular amplification of two unequivocal species-specific genes from A. marginale: msp5 and msp1β. Twenty five giant anteaters and tick organs (salivary glands, gut and oviduct) from 11 ticks tested positive to the A. marginale DNA amplification. The further molecular characterization through MSP1a tandem repeats analysis revealed the presence of genotypes circulating among giant anteaters that had been previously identified in cattle blood samples from the same geographical region. These results confirm the presence of A. marginale in giant anteaters in Corrientes and suggests that A. dubitatum and A. sculptum ticks could be involved in the transmission among giant anteaters. Future studies will determine the role of these tick species in the wild transmission cycle in the study area and the eventual connection with the domestic cycle.

Transovarial Transmission of Anaplasma marginale in Rhipicephalus (Boophilus) microplus Ticks Results in a Bottleneck for Strain Diversity

“…Similarly, our study group has detected A. marginale in the ovaries of the three-host tick Amblyomma sculptum collected on giant anteaters. These results reinforce the evidence that, after being acquired in a blood meal, A. marginale could replicate and migrate to the ovaries of Ixodidae ticks [45]. Furthermore, the fact that we found six genotypes in the EF that were not present in the donor calf from which they were feeding can be explained by the transovarial acquisition from their female parental tick and not during the blood meal.…”

Molecular surveillance and genetic diversity of Anaplasma spp. in cattle (Bos taurus) and goat (Capra aegagrus hircus) from Hainan island/province, China

“…for cattle. The pathogen has been recorded on several continents, including South America [ 15 – 18 ], Latin America [ 19 , 20 ], Africa [ 21 – 24 ], Asia [ 18 , 25 – 28 ], Australia [ 24 ] and Europe [ 29 ]. However, in China, the reports of marginal apocrysis are very rare in China.…”