COMPARATIVE EVALUATION OF PARASITOLOGICAL AND SEROLOGICAL METHODS FOR THE DETECTION OF NATURAL EHRLICHIA CANIS INFECTION IN DOGS IN ZARIA METROPOLIS, KADUNA STATE, NIGERIA

COMPARATIVE EVALUATION OF PARASITOLOGICAL AND SEROLOGICAL METHODS FOR THE DETECTION OF NATURAL EHRLICHIA CANIS INFECTION IN DOGS IN ZARIA METROPOLIS, KADUNA STATE, NIGERIA

Abstract:

Canine ehrlichiosis caused by Ehrlichia canis is an important and potentially fatal disease of dogs. It has been reported worldwide and is transmitted by the dog brown tick Rhipicephalussanguineus. Detection of E. canis infection can be done by direct identification of inclusion bodies or morulae of E. canis in leucocytes from smears made from blood or from buffy coat and lymphnode aspiration by immunofluorescent antibody test (IFAT) and Dot-ELISA. Molecular techniques such as Polymerase chain reaction (PCR) are also used as diagnostic methods. This research work was undertaken to compare the sensitivity of four different diagnostic tests for Ehrlichia viz: thin blood and buffy coat smear examinations, Ehrlichia culture test and a commercially available rapid immunochromatographic assay (Rapid Ehrlichia canis antibody) test in the detection of natural E. canis infection in dogs in relation to breed, age and sex. A total number of 100 dogs comprising 62 males, 38 females were randomly selected under natural conditions from residential areas of Zaria, Kaduna state; 77 of the dogs were local, 12 local-exotic crosses and 11 exotic with age range between 1-3 years being the majority (58%). The intracytoplasmic ehrlichial organisms were observed in buffy coat smears of 2 dogs (2.0%) while Ehrlichia culture detected 20 cases (20.0%). Rapid Ehrlichia canis antibody test detected 83 infected dogs (83.0%). The two buffy coat positive were also positive for the Ehrlichia culture and rapid E. canis antibody tests. Dogarawa ward had a high prevalence rate of 40.0% using the Ehrlichia culture test, while Basawa revealed a 90.0% rate using the rapid antibody test. There was no significant statistical association between buffy coat smears and the breed, age or sex (p>0.05). A significant statistical association was observed between the rapid antibody test with the breed (p=0.019) and age (p=0.001) while sex showed no significant association (p>0.05). No significant association was observed for age, sex and breed in relation to Ehrlichia culture test. There was a slight level of agreement between the applied detection vii methods (buffy coat smear vs Ehrlichia culture; 0.151; p< 0.04, buffy coat smear vs serology; 0.008; p< 0.518, serology and Ehrlichia culture test; 0.069; p< 0.110). Dogs recruited for the study were apparently healthy. However, physical examination revealed fever in 15% of the dogs, 15% had ticks, 10% were emaciated and had rough hair coats, 3% had pale mucus membranes, 1% had diarrhea, blood tinged urine, scrotal edema, and worms in faeces while 2% were anorexic. Thrombocytopenia was the most consistent haematological finding in both the positive and negative groups of dogs showing also a significant statistical difference, followed by leukocytosis (lymphocytosis). Serum Biochemical analysis revealed increased albumin levels in the infected groups of dogs followed by a decrease in urea in both the infected and uninfected groups. Hyperproteinaemia however, was the most consistent finding in both groups. The study showed that in addition to haematological characterization, a combination of parasitological and serological investigation methods is recommended for rapid detection of canine ehrlichiosis.

COMPARATIVE EVALUATION OF PARASITOLOGICAL AND SEROLOGICAL METHODS FOR THE DETECTION OF NATURAL EHRLICHIA CANIS INFECTION IN DOGS IN ZARIA METROPOLIS, KADUNA STATE, NIGERIA

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