Protocolos terapêuticos no tratamento da erliquiose monocitica canina

Abstract

The bacterium Ehrlichia canis affects mainly dogs, but can also infects humans. In dogs, it is the causative agent of the canine monocytic ehrlichiosis, a very common disease in veterinary practice, which may present as an acute, subclinical or chronic disease and can determine different clinical manifestations. In its chronic form often leads the animal to death. It is transmitted by the tick vector, Rhipicephalus sanguineus and co-infections with others hemoparasites are commonly observed. In Brazil, the canine monocytic ehrlichiosis is the most frequent hemoparasitosis, however canine infectious cyclic thrombocytopenia (Anaplasma platys) and more recently canine granulocytic anaplasmosis (Anaplasma phagocitophilum) have been reported. The treatment is based in antibiotics, and doxycycline is the first choice drug. In Brazil, it is used twice a day for three weeks (10 mg/kg), which requires time and dedication from dog’s owners. The drug administration every 12 hours is often a complicating factor, and therefore different treatment protocols were herein evaluated in order to establish protocols that can facilitate the treatment of the animals. A total of 51 dogs naturally infected with E.canis, where 18 were co-infected with A. platys, confirmed by polymerase chain reaction (PCR) were treated with five distinct treatment protocols: Azithromycin 10 mg/kg orally every 24 hours for 28 days; enrofloxacin 10 mg/kg orally every 24 hours for 28 days; imidocarb dipropionate 5mg/kg SC, administered twice with a 14-day interval; doxycycline 20mg/kg orally every 24 hours for 28 days and long-acting oxytetracycline 20mg/kg intramuscular, administered four times with a 7-day interval. Animals were monitored weekly by complete blood tests. Peripheral blood samples were collected to perform PCR after treatment. Laboratorial findings related with this disease were: anemia, thrombocytopenia and leukopenia. These were good parameters for evaluating treatment response, since all showed values lower than normal levels before treatment and have returned to normal levels after the treatment, with significance (p≤0.05). Treatment with doxycycline (20mg/kg PO SID 28 days) and with long-acting oxytetracycline (20mg/kg intramuscularly with 7 days intervals until 28 days) were effective, confirmed by PCR, in association with the normalization of hematologic parameters. However, the results showed a failure in attempt to treat the ehrlichiosis with enrofloxacin, imidocarb dipropionate and azithromycin using a seven day protocol. Significant high values of alanine transaminase (ALT) and urea in dogs treated with oxytetracycline can suggest toxicity of this drug for dogs. Therefore we could conclude that doxycycline and the long-acting oxytetracycline were effective in the treatment of canine monocytic ehrlichiosis as well as in the treatment of canine infectious cyclic thrombocytopenia.