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Description:
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Canine babesiosis is an important worldwide disease caused by protozoan
hemoparasites of the genus Babesia , which are primarily transmitted to a dog by the bite
of an Ixodid tick , although vertical transmission has recently been reported . The disease
is typically characterized by hemolytic anemia , fever , splenomegaly , and
thrombocytopenia , with clinical signs ranging from clinically normal to acute anemia .
Death may even result in some severe cases . Two species of Babesia , Babesia gibsoni
and Babesia canis , have long been known to cause babesiosis in dogs . To date , almost
all B . gibsoni infections in the United States have been reported in American Pit Bull
Terriers or in dogs associated with the breed through either transfusion or fighting .
Dog blood samples received from kennels , shelters , and veterinary clinics
throughout Texas were tested for the presence of B . gibsoni and B . canis . A total of 254
samples were tested for B . gibsoni and B . canis by light microscopy and polymerase
chain reaction (PCR ) . Babesia gibsoni was detected in four of the dogs tested and B .
canis was detected in one of the dogs tested . The average packed cell volumes (PCVs )
of infected dogs were compared with those of uninfected dogs , with the infected , on
average , having lower PCVs . Molecular characterization of the small subunit ribosomal RNA gene and the ribosomal RNA internal transcribed spacer regions was performed on
all sequences obtained in this study , and results were consistent with those previously
reported for B . gibsoni and B . canis . Also , positive samples and additional samples
provided by North Carolinia State University were used to initiate in vitro cultures of the
parasites . To date , one isolate of a large unknown Babesia sp . from a North Carolina
dog was successfully established in vitro . The establishment of Babesia spp . parasites in
culture may aid in the development of a vaccine for babesiosis and will also be
beneficial in improving diagnostic tests for the parasite . |