URINARY EXCRETION OF B. CANIS IN INFECTED MALE DOGS BEFORE AND AFTER CASTRATION (PRELIMINARY REPORT)

WANKE MM,; ELENA S; MONACHESI, NORMA; COMERCIO, ELIDA; BALDI, PC

Wroclaw

Congreso; 17th EVSSAR Congress; 2014

European Veterinary Society for Small Animal Reproduction

Introduction and aim. Brucella canis is primarily a dog pathogen but can be transmitted to humans, thus constituting a zoonotic infectious disease. The number of human cases has increased in recent years and there is general agreement in that the disease is underdiagnosed. Dogs acquire the infection through mucosae and contagion occurs during sexual intercourse, artificial insemination with contaminated semen, through the transplacental route, o by contact with contaminated environmental sources, in the later case through the oronasal route. Infected bitches contaminate the environment through vaginal discharges during estrous, abortion or the postpartum period. In contrast, if they are in anestrous or have been castrated, they are unable to infect healthy dogs. Female urine is usually non-infectious as it contains a low number of B. canis organisms. Testicles, epididymis, and prostate are natural reservoirs of B. canis, and due to the anatomical link between the urinary and genital systems the number of brucellae in urine is higher in male dogs than in females. Cases of contagion from infected male dogs to healthy males living in close contact have been reported. Such studies have been performed in non-castrated dogs (Carmichael, personal communication), but similar studies in castrated dogs have not been performed. Taking into account that male castration results in the elimination of bacteria contained in testicles and epididymis, and that the prostate becomes atrophic, the aim of the present study was to demonstrate that after male castration the urinary concentration of B. canis falls to levels similar to those found in female urine, thus becoming non-infectious for other dogs or for people in close contact with the animal. Materials and methods. The study included dogs referred to the Theriogenology Service of the School of Veterinary Sciences of the University of Buenos Aires due to symptoms compatible with brucellosis or close contact with infected dogs. Urine was obtained by urethral catheterization and was submitted to the Brucellosis National Reference Laboratory (DILAB-SENASA). One hundred microliters of urine were plated onto Tryticase soy agar and incubated at 37º C for 7 days. The concentration of Brucella organisms was determined by CFU counting and was expressed as CFU per ml of urine. Animals were castrated and one month later urine samples were obtained for Brucella counting. The urinary concentrations of bacteria before and after castration were compared. Results. From 201 serologically positive dogs seen in the Theriogenology Service from February 2011 to Agust 2014, 34 were males. Urine culture was possible in 18 cases, with B. canis isolation in 10 cases. A post-castration urine sample could be obtained in 6 of these 10 dogs, and a marked reduction in the urinary concentration of B. canis was observed in all cases. Such concentration fell from 21,000 CFU/ml in sample 1 to 0 CFU/ml in sample 2 in one dog, from 350,000 to 2,500 CFU/ml in a second dog, from 4,500 to 190 CFU/ml in a third dog, from 15,000 to 0 CFU/ml in a fourth dog, from140,000 to 0 UFC in a fifth dog, and 13,000 to 0 in the last dog. Conclusions. These results suggest that the concentration of B. canis in the urine of infected male dogs diminishes markedly after castration, thus reducing the risk for environmental contamination. While the number of dogs analyzed is low to conclude that the diminution of urinary bacterial load eliminates the risk of contagion, these results suggest that this may be a possible scenario.