Babesia–a historical overview.

The research paper provides a historical perspective on the genus Babesia, a group of parasites that infect red blood cells, comparing it with Theileria, another genus of similar parasites. It also discusses the need for potential reclassification of certain species based on molecular characteristics.

Brief History of Babesia

• The article begins by summarizing the history of the genus Babesia, a group of parasites most commonly known to cause disease in animals, but can also cause disease in humans.

Comparison with Theileria

• The paper notes several key differences between Babesia and Theileria, another genus of non-pigment-forming hemoparasites.
• Babesia does not exhibit extra-erythrocytic multiplication (a reproductive process outside of red blood cells) known as schizogony, while Theileria does.
• In the vector tick that often transmits these parasites, Babesia undergoes transovarial transmission (from mother to offspring) whereas Theileria only carries out transstadial transmission (from one developmental stage to another).
• Babesia typically reproduces within red blood cells by a process called budding, which results in two offspring (merozoites), while Theileria’s replication typically produces four merozoites, often in a formation resembling a Maltese cross.

Reclassification of Species

• The article suggests that what is commonly referred to as Babesia microti does not fit the typical characteristics of Babesia and should perhaps be considered a type of Theileria. The use of the term ‘human theileriosis’ is proposed as a substitute for ‘babesiosis’.
• Similarly, Babesia equi, a piroplasm that affects horses, is more commonly referred to as Theileria equi nowadays.
• The author suggests, based on molecular evidence, that a new genus might need to be created for these parasites that do not fit neatly into either existing category.

Babesia Species in Domestic Animals

• The paper concludes with a brief discussion on species of Babesia that affect domestic animals, providing their details in a table. These include common parasites responsible for diseases in livestock and pets.