Invited review: Incidence, risk factors, and effects of clinical mastitis recurrence in dairy cows.

Clinical mastitis (CM) is one of the most frequent and costly diseases in dairy cows. A frustrating aspect of CM is its recurrent nature. This review was conducted to synthesize knowledge on risk of repeated cases of CM, effects of recurrent CM cases, and risk factors for CM recurrence. A systematic review methodology was used to identify articles for this narrative review. Searches were performed to identify relevant scientific literature published after 1989 in English or French from 2 databases (PubMed and CAB Abstracts) and 1 search platform (Web of Science). Fifty-seven manuscripts were selected for qualitative synthesis according to the inclusion criteria. Among the 57 manuscripts selected in this review, a description of CM recurrence, its risk factors, and effects were investigated and reported in 33, 37, and 19 selected manuscripts, respectively. Meta-analysis and meta-regression analyses were used to compute risk ratio comparing risk of CM in cows that already had 1 CM event in the current lactation with risk of CM in healthy cows. For these analyses, 9 manuscripts that reported the total number of lactations followed and the number of lactations with ≤1 and ≤2 CM cases were used. When summarizing results from studies requiring ≥5 d between CM events to consider a CM event as a new case, we observed no significant change in CM susceptibility following a first CM case (risk ratio: 0.99; 95% confidence interval: 0.86-1.14). However, for studies using a more liberal CM recurrence definition (i.e., only 24 h between CM events to consider new CM cases), we observed a 1.54 times greater CM risk (95% confidence interval: 1.20-1.97) for cows that already had 1 CM event in the current lactation compared with healthy cows. The most important risk factors for CM recurrence were parity (i.e., higher risk in older cows), a higher milk production, pathogen species involved in the preceding case, and whether a bacteriological cure was observed following the preceding case. The most important effects of recurrent CM were the milk yield reduction following a recurrent CM case, which was reported to be similar to that of the first CM case, and the increased risk of culling and mortality, which were reported to surpass those of first CM cases.

Prevalence and geographic distribution of Echinococcus genus in wild canids in southern Québec, Canada.

Echinococcus spp. is an emerging zoonotic parasite of high concern. In Canada, an increase in the number of human and animal cases diagnosed has been reported, but information regarding the parasite's distribution in wildlife reservoir remains limited. A cross-sectional study was conducted to estimate the prevalence of wild canids infected with Echinococcus spp. and Echinococcus multilocularis in areas surrounding populated zones in Québec (Canada); to investigate the presence of areas at higher risk of infection; to evaluate potential risk factors of the infection; and as a secondary objective, to compare coproscopy and RT-PCR diagnostic tests for Taenia spp. and Echinococcus identification. From October 2020 to March 2021, fecal samples were collected from 423 coyotes (Canis latrans) and 284 red foxes (Vulpes vulpes) trapped in 12 administrative regions. Real-time PCR for molecular detection of genus Echinococcus spp. and species-specific Echinococcus multilocularis were performed. A total of 38 positive cases of Echinococcus spp., of which 25 were identified as E. multilocularis, were detected. Two high-risk areas of infection were identified. The prevalence of Echinococcus spp. was 22.7% (95% CI 11.5-37.8%) in the Montérégie centered high-risk area, 26.5% (95% CI 12.9-44.4%) in the Bas-St-Laurent high-risk area, and 3.0% (95%CI 1.8-4.7%) outside those areas. For E. multilocularis, a prevalence of 20.5% (95% CI 9.8-35.3%) was estimated in the high-risk area centered in Montérégie compared to 2.4% (95% CI 1.4-3.9%) outside. Logistic regression did not show any association of infection status with species, sex, or geolocation of capture (p > 0.05). This study shows the circulation of Echinococcus in a wildlife cycle in 9/12 administrative regions of Québec.