The Complexity of Piroplasms Life Cycles

Abstract

Although apicomplexan parasites of the group Piroplasmida represent commonly identified global risks to both animals and humans, detailed knowledge of their life cycles is surprisingly limited. Such a discrepancy results from incomplete literature reports, nomenclature disunity and recently, from large numbers of newly described species. This review intends to collate and summarize current knowledge with respect to piroplasm phylogeny. Moreover, it provides a comprehensive view of developmental events of Babesia, Theileria, and Cytauxzoon representative species, focusing on uniform consensus of three consecutive phases: (i) schizogony and merogony, asexual multiplication in blood cells of the vertebrate host; (ii) gamogony, sexual reproduction inside the tick midgut, later followed by invasion of kinetes into the tick internal tissues; and (iii) sporogony, asexual proliferation in tick salivary glands resulting in the formation of sporozoites. However, many fundamental differences in this general consensus occur and this review identifies variables that should be analyzed prior to further development of specific anti-piroplasm strategies, including the attractive targeting of life cycle stages of Babesia or Theileria tick vectors.

Molecular survey of tick-borne pathogens in small mammals from Brazilian Amazonia

“…Babesia, Theileria, Cytauxzoon) and suborder Adelorina (e.g. Hepatozoon) represent a group of mammalian blood parasites with highly significant economic, veterinary, and medical impacts (MODRÝ et al, 2017;JALOVECKA et al, 2018). Obligate intracellular coccobacilli pathogenic for certain mammals, including humans, are present in the Anaplasmataceae family of alpha-proteobacteria (DUMLER et al, 2001).…”

Transient Transfection of the Zoonotic Parasite Babesia microti

“…Genome-wide phylogenetic analyses indicate that B. microti defines a new clade in the phylum Apicomplexa. Additionally, the difference in both the copy number and organization of multigene families resulted in the phylogeny and life cycle of B. microti being significantly distant from those of other Babesia and Theileria parasites [21,22]. Therefore, the established transfection methods for other apicomplexan parasites may not be used for B. microti.…”

Serological occurrence for tick-borne agents in beef cattle in the Brazilian Pantanal

“…It is known that Nellore cattle have innate resistance against the fixation of the R. microplus tick to the skin, which is avoided by licking (Veríssimo et al, 2015). Thus, it is also hypothesized that calves have lower licking reflex compared to cows, thus allowing a higher number of fixed larvae and nymphs, which would have the sporogenic cycle of B bovis and B. bigemina, respectively, activated in their salivary glands (Jalovecka et al, 2018). The moderate correlation found among co-seropositive animals for A. marginale x B. bovis x B. bigemina, is probably due to the constant presence of the R. microplus tick in the herds, the biological vector common to all three agents.…”