Description of an outbreak of canine rangeliosis in the northwest littoral of Uruguay

Abstract

Canine rangeliosis is a disease caused by the protozoan Range­lia vitalii and transmitted by ticks. It affects domestic and wild canines, causing hemolytic anemia and thrombocytopenia. In Uruguay it has been reported in the following counties: Arti­gas, Salto and Treinta y Tres. The present study describes a ca­nine rangeliosis outbreak in the northwest littoral of Uruguay, diagnosed by epidemiological, clinical, hematological, anato­mopathological and molecular techniques (PCR / sequencing). The study was based on 9 cases of dogs, Fawn Brittany Grif­fon breed, used for hunting; from a farm near Quebracho, Pa­ysandú County. Eight animals died and one responded to the treatment. The main clinical signs were apathy, jaundice, fever, bloody diarrhea and bleeding from nostrils and tips of the ears. The hematological findings were anemia, thrombocytopenia and leukocytosis. Main macroscopic lesions were characterized by paleness, generalized jaundice, splenomegaly, lymphadenomeg­aly, and hepatomegaly. The principal histopathological lesions were interstitial nephritis with tubular degeneration and necro­sis, myocarditis, centrolobulillar hepatic necrosis, edematous and congestive lung, lymphoadenitis and perivascular mononu­clear inflammatory infiltration in spleen. In several organs were observed R. vitalii zoites inside the cytoplasm of endothelial cells. In some animals and as well as in dog kennels were pres­ent Amblyomma aureolatum. DNA was extracted from blood of two cases and a fragment of the 18s ribosomal RNA gene of Piroplasm was amplified by PCR. The sequence obtained was compared to the sequences registered in the GenBank using the BLAST tool. The result showed a homology between 99-100% with R. vitalii.