Perfil electroforético del suero sanguíneo en caninos diagnosticados con ehrlichiosis

Abstract

Canine ehrlichiosis is a tick-borne disease caused by several species of rickettsia (Rickettsiae) belonging to the genus Ehrlichia, including E. canis, E. ewingii, and E. chaffeensis. Because the disease is generally asymptomatic (subclinical phase), it constitutes an important epidemiological factor for the spread of the infection. There are several techniques for the diagnosis of Ehrlichiosis, that include indirect immunofluorescence (IFI), ELISA, direct smear, solid layer chromatography and the polymerase chain reaction (PCR), being the ELISA method and the direct smear, the most used. This work raises the possibility of using a variation of the gel electrophoresis technique with easily obtainable buffers that have a good resolution of serum protein fractions for the diagnosis of canine Ehrlichiosis, in combination with the determination of other parameters such as the Hematocrit and the average diameter of the erythrocytes. The analysis of 31 dogs that came to the UTMACH Veterinary Specialties Teaching Clinic, which underwent a rapid test with the SensPERT Ehrlichia canis Ab commercial kit, allowed the identification of 19 seropositive and 12 seronegative animals. The white layer smear analysis only confirmed the presence of morulae in 31.82% of the seropositive individuals. The seropositive dogs presented lower hematocrit values ​​and a marked macrocytosis evidenced from the analysis of the mean diameter of the erythrocytes. The concentration of total proteins and total globulins was higher in seropositive dogs, whereas for the Albumin concentration quantified by the Bromocresol Green method, no statistical differences were detected between seropositive and seronegative dog groups. Agarose gel electrophoresis and subsequent analysis of the respective densitograms allowed to establish hypoalbuminemia and evident increases in the fraction of gamma globulins in seropositive canines. When the Albumin fraction was analyzed by the densitometric data obtained from the electrophoretic fractionation in agarose gel, the statistical differences revealing a hypoalbuminemic condition in seropositive dogs. The albumin/globulin ratio (A/G) from the data obtained by colorimetry was higher in seropositive dogs, whereas the densitometric analysis of the electrophoretic runs revealed an inverse behavior. The usefulness of electrophoresis, hematocrit and mean erythrocyte diameter in the diagnosis of canine Ehrlichiosis is discussed. On the base of the results obtained, a series of recommendations are proposed that include: a) consider the use of electrophoresis to evaluate the health status of animals and subclinical processes, b) use the proteinogram for the control and follow-up of patients positive to Ehrlichia canis in order to adopting decisions regarding the therapy to be indicated, c) perform electrophoretic studies in coinfections or other haemoparasitic diseases, d) use of the Hematocrit as a routine parameter to be considered in clinical practice when evaluating canine patients with suspected Ehrlichiosis and e) and continue this line of research including carrying out a complete blood count and blood biochemistry in order to have a systemic view of the state of the disease in patients who come to a veterinary consultation.