Sero-Epidemiological Investigation Of Toxoplasma Gondii,Neospora Caninum,Chlamydia And Bluetongue Virus In Black-Boned Sheep And Goats In Yunnan Province

Black-boned sheep and goats were originated from Lanping County,Nujiang Prefecture,Yunnan Province in China.Black-boned sheep and goats have the characteristics of dark tissue compared to ordinary sheep,which are attributed to the presence of excessive melanin in black-boned sheep and goats.The unique characteristics of black-boned sheep and goats can be stably inherited which are rare resource in the world.The meat of black-boned sheep and goats are delicious and many organs can be used as medicine,which is very popular with consumers as delicious food,medicine and health care products.At present,the black-bone sheep and goats industry are still in its infancy,and there are only limited number of black-bone sheep and goats in China,which is far from meeting the needs of the market.Therefore,the market potential of black-boned sheep and goats is great and the prospects of breeding is good.Toxoplasma gondii,Neospora caninum,Chlamydia and Bluetongue virus(BTV)can cause serious economic losses to sheep and goats,which hinder the development of animal husbandry in China.T.gondii is an intracellular zoonotic parasite which can infect almost all warm-blooded animals and humans.T.gondii can cause abortions in humans and animals,with felids as definitive hosts.T.gondii infection in sheep and goats generally do not exhibit any clinical symptoms;however,pregnant sheep often have abortion.N.caninum is an obligate intracellular protozoan in which dogs and foxes are the definitive hosts,and sheep,cattle donkeys and pigs act as its primary intermediated hosts.Both sheep and goats are susceptible to N.caninum.Pregnant ewes show abortion,stillbirth or weak lambing,and fetus can have encephalomyelitis.Chlamydia is an obligate intracellular Gram-negative pathogen which has a wide range of hosts and complicated pathogenicity.The main clinical symptoms of Chlamydia infection were abortion,weak lambing or dead lambing.BT is a vector-borne viral disease which effects wild and domestic ruminants.Animal infections with BTV are mainly manifested by pyrexia,nasal discharge,haemorrhages and generalized oedema,which cause huge economic losses to animal husbandry.In this study,the seroprevalence of T.gondii,Chlamydia and BTV infection in 481 black-boned sheep and goats,and the seroprevalence of N.caninum infection in 468 black-boned sheep and goats from three counties of Yunnan Province was examined by indirect enzyme-linked immunosorbent assay(iELISA),modified agglutination test(MAT),indirect haemagglutination assay(IHA)and competitive enzyme-linked immunosorbent assay(c-ELISA),respectively.The T.gondii seroprevalence in blackboned sheep and goats was 36.80%(177/481).For T.gondii infection the logistic regression analysis results showed that region was considered as a risk factor.The seroprevalence of N.caninum in blackboned sheep and goats was 8.55%(40/468);by logistic regression analysis,region,gender,age and species were considered as risk factors.The overall Chlamydia seroprevalence in black-boned sheep and goats was 20.79%(100/481).Region and gender were the risk factors by logistic regression analysis.The overall BTV seroprevalence in black-boned sheep and goats was 27.65%(133/481),and the region,gender,age and species were considered as risk factors by logistic regression analysis.To our knowledge,this is the first serological evidence of T.gondii,N.caninum,Chlamydia and BTV infection in black-boned sheep and goats in Yunnan Province,China,which fills the knowledge gaps in epidemiology of the four pathogens in black-boned sheep and goats,and provides baseline date for the prevention and control of these diseases.Meanwhile it has important public health implications.