Parasitologic and molecular diagnosis of canine babesiosis in Goiânia, Brazil

Abstract

Canine babesiosis is a disease caused by protozoans of the genus Babesia. The
species Babesia canis and Babesia gibsoni are spread all around the world.
Babesia canis is classified into three subspecies: B. canis canis, B. canis vogeli and B. canis rossi. The identification of individual species has traditionally been
based on the morphologic features of the intraerythrocytic forms. B. canis, a large
piroplasm (4-5?m) which usually occurs as a single pear-shaped piroplasm or pairs
of merozoítes that divides through binary fission within the erythrocyte, and B.
gibsoni, a small parasite that commonly appears as individual ring forms or piriform
bodies sized between 1 and 2.5?m. This identification method cannot be used to
morphologically distinguish among the B. canis subspecies. The objective of the
present study was to identify the species and subspecies of the Babesia organisms
involved with infections of dogs living in the city of Goiânia, state of Goiás, Brazil, by
using morphological and molecular techniques. Blood samples were obtained from
dogs presenting hemoparasitosis-like clinical signs and submitted to blood smear.
Samples that tested positive were then submitted to DNA extraction (30 samples,
total). The microscopic examination has shown varied forms of trophozoites and
merozoites. Some samples presented intraeritrocytic bodies with morphological
features that most resembled B. gibsoni and other equivalent forms of B. canis. The
subspecies-specific diagnosis by PCR confirmed the molecular identity of B. c.
vogeli in the 30 samples. In conclusion, the results indicate that the subspecies B. c.
vogeli is well spread in naturally infected dogs from the city of Goiânia, in spite of
some morphologic differences observed among specimens.