In this study, we first detected M.conjunctivae in goats from Ningxia Hui Autonomous Region. The diseased goats showed clinical symptoms such as poor appetite, frequent blinking, corneal opacity, ulcers and even blindness, which was highly consistent with the reports on the clinical symptoms of wild goats and antelope written by Marco I [15]. The symptoms such as frequent tears, increased eye feces, mild conjunctivitis, or corneal opacity in both eyes were observed in diseased goat, which was very similar to the typical clinical symptoms of small ruminants reported by Fernandez-Aguilar X [16]. After observing the diseased goat, it was found that the clinical symptoms were mildly manifested as continuous tears, conjunctival congestion and peripheral corneal edema; in severe cases, it is manifested as keratitis, corneal ulcer and even corneal perforation, resulting in permanent blindness. The above is the same as the report of infectious corneal conjunctivitis in goat was reported by Williams H J [17]. This study revealed that the clinical symptoms of captive goats infected with M.conjunctivae were the same as those of small ruminants such as wild goats, antelope and goats.
Mycoplasma can escape the host's immune response in various ways, thus surviving in the host body [18]. Almost all of these escape processes can cause changes in the structure and expression function of mycoplasma surface membrane proteins, so these mechanisms are essential for mycoplasma to adapt to the host and chronic colonization in the host [19, 20]. Once the mycoplasma is colonized in the body, it is difficult to completely remove it, which makes the body vulnerable to the invasion of other pathogens and easy to mix with other pathogenic microorganisms. For example, cases of mixed infection with pathogens such as Rickettsia [21], Mycoplasma agalactiae [22] and Chlamydia psittaci [23] have been reported. Therefore, under the stress conditions of long-distance transportation, feed replacement and environmental change, we should attach great importance to the health status of goats and do a good job in the prevention of various diseases in time to improve the survival rate of purchased goats.
In China, long-distance transportation between livestock is an important factor in the spread of animal diseases [24]. On the one hand, due to the stress response of long-distance transportation and the inadaptability of climatic conditions, the resistance of the animal body is reduced, so some conditional pathogenic bacteria breed in large quantities, which leads to the emergence of animal epidemics. On the other hand, the detection was not strictly strengthened before the introduction, and isolation observation was not implemented after the introduction. Due to the introduction back is captive breeding, breeding density is larger, poor ventilation, and poor management, bacteria, and viruses will take the opportunity to enter and cause disease. In addition, the genetic differences between animal individuals may also affect the occurrence, development and prognosis of the disease [25]. This batch of goats has introduced back to Ningxia autonomous region from another province, and the related diseases were not detected at the time of introduction, and the isolation observation was not paid attention to after introduction. Therefore, to avoid similar situations, disease detection should be strengthened before introduction, and isolation should be carried out under the relevant requirements of veterinary laws and regulations after introduction. The quarantine period for large and medium-sized animals is 45 days, and the quarantine period for small animals is 30 days. During the quarantine period, a suitable environment such as dry, clean and well-ventilated should be provided, and anti-stress drugs should be given to animals to minimize the possibility of epidemic disease.