Molecular evaluation of piroplasms and hematological changes in canine blood stored in a clinical laboratory in Niterói, Rio de Janeiro

Piroplasm species were analyzed by molecular tools in total 31 blood samples from positive dogs, previously checked by stained slides, stored until DNA extraction between 2016 to 2018 in the laboratory Clinical Analyzes in Niterói, Rio de Janeiro. The piroplasms were identified by PCR, targeting the 18S rRNA gene and sequencing. From the total number of samples only 24 (77.4%) were positive and show adequate nucleotide sequences for interpretation with identity between 93%-100% with Babesia vogeli in compared to the sequences isolated of infected dogs from other states in Brazil deposited on GenBank. Most of dogs infected with B. vogeli had anemia (62.5%) and thrombocytopenia (95.8%). The findings of this study are compatible with previous reports in the literature and highlight B. vogeli as the most incriminated species in canine piroplasmosis in Brazil, and thrombocytopenia the hematological alteration most frequently identified in this infection. It is important to note that this is the first study involving the molecular characterization of piroplasms in the metropolitan region of Rio de Janeiro, based on PCR followed by sequencing.

Experiments in the “Tryposafrol” Treatment of Trypanosomiasis (T. brucei) in Guinea-pigs and of Piroplasmosis in Dogs

All of our guinea-pigs infected with Trypanosoma brucei (strain “ferox”) died whether they were treated or not. It is evident that both tryposafrol and novo-tryposafrol exerted a directly injurious effect upon the guinea-pigs. Reckoning the day on which the guinea-pigs were inoculated as day 1, the 19 treated guinea-pigs died respectively on days 5, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 11, 18, 19, 19, 26, 27 and 33. The six untreated guinea-pigs died respectively on days 23, 25, 25, 27, 44 and 45. The two preparations of the dye are therefore worse than useless as remedies for Nagana in guinea-pigs.Five dogs were infected with Piroplasma canis (Cambridge strain) of which four were treated and one not treated with novo-tryposafrol.All of the dogs died although treatment was given under the most favourable conditions, starting on the day of inoculation. The four treated dogs died on days 12, 9, 17 and 12 after inoculation respectively; the untreated (control) dog died on the 13th day. The drug exerted no influence upon the course of the disease, nor upon the appearance of the parasites and their progressive increase in the blood. Novo-tryposafrol may therefore be regarded as useless in the treatment of canine piroplasmosis, and, judged from these results on dogs, it will no doubt prove to be equally useless in the treatment of bovine piroplasmosis when it has received a scientific trial in competent hands.In view of the negative results obtained by ourselves and other independent investigators, working especially with trypanosomiasis, we conclude that the value of tryposafrol or novo-tryposafrol as a remedy for any of the diseases enumerated by the authors is open to grave doubt since the chief claims as to its efficacy were based on experimental results which the authors state that they obtained with Nagana.