Evaluating the dynamics and efficacy of a live, attenuated Mycoplasma anserisalpingitidis vaccine candidate under farm conditions

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The aim of the present study was to monitor the dynamics and to measure the safety and efficacy of a live, attenuated, thermosensitive Mycoplasma anserisalpingitidis vaccine candidate, namely MA271, in geese breeder flocks under field condition. Two rearing flocks were vaccinated with MA271 at four-week of age and boosted at 24 weeks of age by cloaca inoculation (1 ml) and eye-dropping (60 µl). The geese then were transported to multi-aged breeding farms. Two breeding flocks served as controls. Colonisation of the cloaca by MA271 showed 75% maximum prevalence between 4 and 6 weeks after the first vaccination. Then the prevalence decreased to 25% until the cooler, humid fall months which coincided with the booster vaccination. Boostering raised cloacal colonisation to 100%. No clinical signs were observed in the vaccinated birds. After transportation to five multi-aged breeding farms, the wild-type strain appeared beside MA271 in three flocks. In one flock the wild-type strain completely displaced MA271, while in one flock only MA271 was detected. Only wild-type strains were detected in the control flocks, however, due to a HPAI outbreak both flocks were exterminated before the end of the study. Based on the available data the median percentage of infertile eggs were 3.7-5.1% in the MA271 vaccinated flocks, while 7.7% in the non-vaccinated flock. In conclusion MA271 is able to colonise the cloaca of geese under field condition. MA271 proved to be safe and presumably provides protection against M. anserisalpingitidis induced reproduction losses.