Abstract
Mycoplasma bovis is increasingly recognized worldwide as an important cause of disease with major welfare and production impairments on cattle rearing. Although it was detected in veal calves and beef cattle, little is known on the infection impact and on its temporal morbidity pattern in Italian dairy herds. Thus, this study aimed to investigate the involvement of M. bovis on fatal calf pneumonia outbreaks that occurred during 2009–2019 in 64 Italian dairy farms. Furthermore, a deeper diagnostic workup of concurrent infection with other viral and bacterial respiratory pathogens was assessed. Out of the investigated fatal pneumonia cases, M. bovis was frequently detected (animal prevalence, 16.16%; 95%CI, 11.82–21.33; herd prevalence, 26.56; 95%CI, 16.29–39.08) either as the single agent of the disease in more than half of the positive samples (20/37) or in concurrent infections with Histophilus somni (9/37, 24.3%), Mannheimia haemolytica (6/37, 16.621%), Trueperella pyogenes (1/37, 2.70%), Pasteurella multocida (1/37, 2.70%), bovine respiratory syncytial virus (5/37, 13.51%), and bovine viral diarrhea virus (2/37, 5.55%). Based on time-series analysis, M. bovis was recorded in the area since 2009 with outbreaks displaying a clear morbidity seasonal pattern with peaks in April (43.21%) and in September (13.51%). This might be due to the stressing conditions during spring and late summer periods. Results of this study highlight that M. bovis infection warrants consideration, and control measures are needed given its involvement in lethal pneumonia outbreaks in dairy herds from an extended area.
Highlights
Mycoplasma bovis is a cell-wall-less bacterial pathogen, included in the class of Mollicutes [1]
From 2009 to 2019, 229 lung samples of calves (
M. bovis was the agent most frequently detected from fatal calf pneumonia cases (AP, 16.16%; 95% confidence interval (95%CI), 11.82–21.33) occurring in dairy farms (HP, 26.56; 95%CI, 16.29–39.08) from Southern Italy during a 10-year period
Summary
Mycoplasma bovis is a cell-wall-less bacterial pathogen, included in the class of Mollicutes [1] It is recognized as a causative agent of several diseases in cattle that have severe economic consequences for producers [1]. M. bovis is probably the most common causative agent of mycoplasma mastitis, with arthritis and otitis media sometimes observed in infected animals [2]. It contributes to the occurrence of the bovine respiratory disease complex (BRD), a multifactorial syndrome consisting of chronic bronchopneumonia and pharyngitis, often the infection can remain subclinical [3]. It was shown that M. bovis is able to maintain viability in the environment for months at low temperatures and weeks at room temperature on a variety of substrates in infected herds [5]
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