Molecular Investigations Of Cryptosporidium And Giardia In Children And Calves In Hubei Province,China

Parasitic protozoa of the Cryptosporidium and Giardia are two significant zoonotic pathogens.These protists are usually directly transmitted to the human and other animal hosts via the faecal-oral route,following the ingestion of infective oocysts or cysts,and can cause cryptosporidiosis and giardiasis-often associated with diarrhoea.Findings of recent epidemiological research indicate that zoonotic transmission plays a significant role in cryptosporidiosis and giardiasis.Cattle,particularly young calves,infected with these protists can represent a significant source of zoonotic infections and diseases.Nevertheless,epidemiological information on the species and genotypes that occur in both humans and animals are lacking in some areas such as Hubei province,China.To address the above issues,we conducted the following studies:In Chapter 1,I provide the salient background on these two protists,key aspects of the species,life cycles,routes of transmission,pathogenesis,diagnosis and the control of cryptosporidiosis and giardiasis,and summarise known species and genotypes,and provide a perspective on future research towards the prevention and control of cryptosporidiosis and giardiasis,guided by molecular biological studies.In Chapter 2,I conducted a study to determine the prevalence of Cryptosporidium,Giardia and Enterocytozoon infection in diarrhoeic children from Wuhan,China for the first time.Faecal samples were collected for anonymous(individual)children with diarrhoea at the Outpatient Department in Wuhan Pediatric Hospital and Renmin Hospital of Wuhan University(June 2016 and August 2016).The survey showed that C.meleagridis,Giardia assemblage A and Enterocytozoon genotype D predominated in this study of diarrhoeic children in Wuhan.It is noteworthy that,C.meleagridis(mainly infecting avian hosts)was found to dominate in the children studied in Wuhan,this finding provide the basics of transmission of this enteric pathogen in humans in China.In Chapter 3,calves were investigated for Cryptosporidium and Giardia in Hubei province,China.Samples were collected from pre-and post-weaned calves(1 to 12 weeks old)from one beef farm and five dairy farms in the northern,eastearn and western regions of Hubei(September to December 2016).The aim was to explore the species and genotypes of Cryptosporidium and assemblages of Giardia.C.bovis,C.andersoni,C.bovis and Giardia assemblage E were identified and questions regarding zoonotic transmission were discussed.Chapter 4 provides a general discussion of the results achieved and provides a perspective on implications and future research.This thesis contributes to knowledge in the field infectious/parasitic diseases in Hubei,China,and proposes that further work be conducted to explore Cryptosporidium and Giardia on much larger scale to better understand their epidemiology throughout China.