Classification

Domain - Eukarya
Kingdom - Alveolata
Phylum - Apicomplexa
Class -  Aconoidasida
Order - Piroplasmida
Family - Babesiidae
Genus - Babesia
Species - Babesia canis

Subspecies - vogeli, canis, and rossi

Domain Eukarya

"Eukarya" originates from two Greek root words meaning "true" and "nucleus." Babesia canis belongs to the Domain Eukarya because it has both a true nucleus and membrane-bound organelles.

Kingdom Alveolata

Organisms in the Kingdom Alveolata have the unique charactersitic of cortical alveoli. B. canis is categorized as an alveolate because of the flattened vesicles (cortical alveoli) under its outer membrane.

        

Phylum Apicomplexa

The Phylum Apicomplexa is composed of parasitic protozoans, most of which feed off of an animal's blood through a blood-sucking arthropod. This vector-to-host process is used by the parasite B. canis, qualifying it as an apicomplexan.

Class Aconoidasida

 B. canis is classified in the Class Aconoidasida because, as the Greek prefix indicates, it is lacking a particular feeding structure called a "conoid" (a-conoid) in its full life-cycle.

Order Piroplasmida

Piroplasmids are parasites that are host and vector specific. A synapomorphy of the piroplasmids is the trophozoite stage of the life cycle, which can be separated from an erythrocyte by a single membrane, unlike the usual two membranes. Piroplasmids are unique in to dogs, though in some cases it has been found in other mammals (Lack et al. 2012). Nutrition is obtained by feeding on the blood the vector eats as well as the canine host’s blood. Two families are derived from this order, Babesiidae and Theileriidae (Criado-Fornelio et al. 2003).
 
Family Babesiidae

Babesiidae is a parasite that reproduces via binary fission or schizogony. Depending on the part of the lifecycle it is in, it can be round, piriform, or oval. Babesiidae feeds upon the erythrocytes of its mammalian host, or off of its tick vector. If Babesiidae infects its host, the host may develop a disease (Canning and Winger, 1987).

Genus Babesia     

The genus Babesia can be classified as a tick transmitted hemoprotozooan. Babesia tends to be transmitted into a mammalian or bird host via a tick vector. Thus it is a huge concern to those in the agriculture field, or anyone with pets. The lifecycle of Babesia is thought to be derived via tick vector, and thus has evolved to using ticks for transmission exclusively (Schnittger et al. 2012).

Species Babesia canis

Babesia canis is a parasite of the genus babesia that primarily affects dogs. These parasites feast upon blood meals while within both the tick vector and mammalian host. B. canis is very specific to the tick vector and tends to be different depending on the geography in which it resides. Different dog hosts have developed various level of immunities to B. canis, though none are completely immune (Chauvin et al. 2009).

             

Figure 1. Phylogenetic tree of the relation between several Babesia species. Adapted by T. Kusiak from the diagram of Caccio et al. 2002.

The three subspecies of B. canis are related in a particular way. B. canis canis, and B. canis vogeli form a sister taxa, while B. canis rossi speciated before them from the most recent common ancestor of the three (Figure 1.). Effectively, rossi has the most distinct form and deadliest effect on its host, while canis and vogeli are both more similar to each other than to rossi, in both form and function.

Babesia gibsoni is one of the most closely related parasites to the species Babesia canis. Both may infect dogs and cause hemolytic anemia and are transferred by a similar (if not the same) tick vector. However, they differ in form and size. Babesia canis is larger and recognized as “pear-shaped” whereas B. gibsoni is much smaller and harder to detect (French et al.) (Figure 2). Babesia odocoilei is comparable to B. canis in much the same way.       

Figure 2. An example of Babesia canis (top panel) and Babesia gibsoni (lower panel). Used with permission from Cornell University; original image located on "eClinPath" website at Cornell University. Located here after June 2014.

              

Figure 3. Babesia canis with relation to other Apicomplexans. Modified from Hikosaka, K et al. 2012. 

This phylogenetic tree shows the relationship between the Archaeoplasmids, Theilerids, and Bebesids. Archaeoplasmids are unique because they undergo binary fission (asexual) and sexual life cycles. Theilerids are parasitic protozoan's that belong to the phlum Apicomplexa. Bebesids are a unique group of parasites that are highly specific to the species of vector, as well as host, that they parasitize (Hikosaka,
 et al. 2012).

 

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