Time for change? A systematic review with meta-analysis of leptospires infecting dogs to assess vaccine compatibility in Brazil.

Dogs are thought to be highly exposed to environmental pathogenic leptospires, possibly acting as potential sources of infection for zoonotic transmission. Vaccination stands as the cornerstone strategy to prevent disease and urinary shedding in dogs, yet the success of vaccination is highly dependent on the correspondence of leptospires circulating locally with those used in vaccine compositions. To provide evidence for vaccine compatibility, and to assess whether there are regional differences on serogroup distribution, we conducted a systematic review with meta-analysis on serological data, characterization of leptospiral isolates and risk factors for seropositivity in dogs from Brazil. Studies reporting canine leptospirosis within the Brazilian territory were eligible for inclusion, and methodology was validated by PROSPERO under registration CRD42020204187. Six electronic databases were searched, and data regarding population, methods, and outcomes were extracted. Sixty-one studies were included to access serogroup distribution and risk factors, with a pooled positivity rate of 19.7% in dog population. Serological evidence indicates that Canicola, Icterohaemorrhagiae and Autumnalis are the most frequently found serogroups. Twenty-eight records were included to access leptospiral strains isolated in Brazil, with n = 56 strains characterized as serogroups Canicola, n = 37 as Icterohaemorrhagiae, n = 2 as Pomona, and n = 1 strain as Australis and Sejroe each. Risk factor analysis revealed that stray dogs, puppies or elderly dogs, male dogs and dogs kept by tutors with poor social and economic conditions are at high risk for infection. The present study revealed overall good compatibility of leptospiral strains circulating locally with those used in vaccines against canine leptospirosis in Brazil. The circulation of serovars Pomona and Grippotyphosa has not been consistently demonstrated, and the inclusion of these serovars in local vaccines cannot be supported by our results. The results also provided serological evidence for the circulation of Serogroup Autumnalis among the studied populations.

Development and characterization of an overtraining animal model.

PURPOSE: Development of an endurance training-overtraining protocol for Wistar rats that includes increased workload and is characterized by analyses of performance and biomarkers. METHODS: The running protocol lasted 11 wk: 8 wk of daily exercise sessions followed by 3 wk of increasing training frequency (two, three, and four times), with decreasing recovery time between sessions (4, 3, and 2 h) to cause an imbalance between overload and recovery. The performance tests were made before training (T1) and after the 4th (T2), 8th (T3), 9th (T4), 10th (T5), and 11th (T6) training weeks. All rats showed significantly increased performance at T4, at which time eight rats, termed the trained group (Tr), were sacrificed for blood and muscle assays. After T6, two groups were distinguishable by differences in the slope (alpha) of a line fitted to the individual performances at T4, T5, and T6: nonfunctional overreaching (NFOR; alpha < -15.05 kg x m) and functional overreaching (FOR; alpha >or= -15.05 kg x m). RESULTS: Data were presented as mean +/- SD. FOR maintained the performance at T6 similar to Tr at T4 (530.6 +/- 85.3 and 487.5 +/- 61.4 kg x m, respectively). The FOR and the Tr groups showed higher muscle citrate synthase activity (approximately 40%) and plasma glutamine/glutamate ratio (Gm/Ga; 4.5 +/- 1.7 and 4.5 +/- 0.9, respectively) than the sedentary control (CO) group (2.8 +/- 0.5). The NFOR group lost the performance acquired at T4 (407.3 +/- 88.2 kg x m) after T6 (280.5 +/- 93.1 kg x m) and exhibited sustained leukocytosis. NFOR's Gm/Ga (3.1 +/- 0.2) and muscle citrate synthase activity were similar to CO values. CONCLUSIONS: The decline in performance in the NFOR group could be related to the decrease in muscle oxidative capacity. We observed a trend in the Gm/Ga and leukocytosis that is similar to what has been sometimes observed in overtrained humans. This controlled training-overtraining animal model may be useful for seeking causative mechanisms of performance decline.