Investigation Of Three Main Blood Canine Protozoans In Nanning And Artificial Preplication For Trypanosoma Evansi On Canines

Object:This study was to investigate the epidemic of 3 canine blood protozoans Babesia, Hepatozoon canis and Trypanosoma evansi in Nanning, Guangxi, China. On the other hand, to investigate the disease course by T. evansi by experimentally infecting the Guangxi strain in dogs, and to find out an optimal treatment formula by evaluating different drug combinations as a reference in the clinical medication.Methods:Canine blood samples were collected from veterinary hospital of Guangxi University in Nanning during November 2013 to November 2014 and stored in fridge until used. Blood smears were made and stained for microscopy. 160 samples were randomly selected for PCR examination in order to detect three main protozoans as mentioned above. PCR products were identified, and finally PCR product was purified by gel extraction kit, followed by DNA cloning and sequencing. Subsequently, the DNA sequences were analyzed by BLAST for performing sequence alignment online. To replicate the dog natural infection in the lab,8 dogs were infected with buffalo origined T.evansi which stored in the lab.3 dogs were infected by intravenously injection,2 dogs were infected by oral administration and 3 dogs as control. We just record and investigate the course of disease, no treatment was given. Another 3 dogs were infected and chemical therapies were given by Diminazene diaceturate (or Berenil Xyalzole) with the dose of 0.15-0.2ml and Pu De An (diminazene compound) with the dose of 3.5mg/kg, to compare the effects against trypanosomiasis.Results:Four strains of Babesia-positive (2.5%) and one strain of Hepatozoon canis (0.625%) were detected among 160 tested samples. The Babesia was identified as B.canis vogeli according to its DNA sequence. However, no Trypanosoma evansi pathogen was found. Dogs could be successfully infected by either intravenous injection (i.v) or oral experimental administration. Among which, two dogs by i.v administration on on 3 day post infection (dpi) and 4 dpi respectively, while blood parasitemia was found in one dog by oral administration on 6 dpi and died on 10 dpi. During the infection, dog body temperature was seen positively associated with cyclical variation. Diminazene diaceturate has no effect against canine T. evansi infection according to the treatment experiment, while Pu De An could reduce the cloinical symptom but was still unable to curetrypanosomatosis within only one course. These results suggested that canine blood protozoan should be addressed in order to prevent in early stage.