The Clinical Observation,Pathogen Isolation And Identification Of A Case Of A Neosporosis Of Goat

In 2016,our laboratory performed the project of "extracellular traps of host against Neospora caninum infection" and purchased nine adult goats from songyuan for experimental animals.The goats were used to collect peripheral blood to separate Neutrophils.Accidently we observed the suspected half-crescent structure in the isolated neutrophils from one of the goats under the light microscope.But this phenomenon did not attract our enough attention.Subsequently,the samples were sent to do the scanning electron microscopy observation and we observed the same half-crescent structure in the neutrophil group without Neospora caninum stimulated and the structure is consistent with the protozoan Toxoplasma gondii and Neospora caninum.After repeated check,we excluded the contaminative possibility of blank samples due to operational errors.Then we doubt that the goat infected Neospora caninum,so we collected the blood of the goat for nested PCR.Finally,preliminary results confirmed that the pathogen is Neospora caninum.Neosporosis is a kind of protozoal disease caused by Neospora caninum which can infect a wide range of hosts.It mainly causes reproductive disorders of dam and motor and neurological symptoms of young animals.Neospora caninum can infect a variety of host,including the intermediate host like sheep and cattle as well as the definitive host like dog and red fox.According to the epidemiological results,Neospora caninum is widely found in sheep in Qinghai,Xinjiang and Inner Mongolia of China.It has become one of the main factors causing reproductive failure in pregnant ewes.The threat of Neospora caninum to the sheep industry cannot be ignored.However,there are few Neosporosis of adult goats have been reported.Meanwhile,there is no effective vaccine and medicines are currently available against Neospora caninum,it has brought difficulty to prevent and control neosporosis.Thus,it is necessary to study clinical symptoms,pathological changes and prevalence rate of neosporosis,develop the vaccine against Neospora caninum,establish the diagnostic methods and explore the therapeutic drugs by obtaining the pathogen.This study is based on the mentioned goat suspected to be infected with Neospora caninum and the main experiment content is divided into the following three parts:(1)Collecting the blood of infected goat to extract the genome of the goat for nested PCR,the result showed that the pathogen of the sheep infected was Neospora caninum.After the clinical observation of infected goats,the sheep showed messy hair,weight loss,poor appetite and neurological symptoms.Pathological anatomy showed pericardial effusion,brain edema and other diseases.Histopathological changes showed that the brain cells were vacuolization,degeneration and inflammation in multiple organs and other pathological changes.(2)Peripheral blood of the infected goat was collected and leukocytes were isolated,and the isolates were inoculated on vero cells for culture and passage.The tachyzoites were completely consistent with the typical culture forms of Neospora caninum under the light microscope.At the same time,observation of the isolates coincided with the typical tachyzoites of Neospora caninum by scanning electron microscopy.The nested PCR was performed to detect the DNA of isolate.All the results confirmed that the isolated pathogeny is Neospora caninum.(3)A preliminary investigation of Neospora caninum infection in four goat farms in the Songyuan area was conducted using the nested PCR.Nine positive samples were observed in the 83 samples tested,with a positive rate of 10.84%.In conclusion,this study confirmed there existed adult goat naturally infected Neospora caninum and the clinical symptoms and pathological histology changes are observed.Then we successfully isolated a Neospora caninum strain.Finally epidemiological investigation was conducted and the positive rate is 10.84%.