Genetic determinants for the transmission of Cryptosporidium spp. among humans and animals in Africa

• Applicants: Professor Dr. Franz Josef Conraths; Privatdozent Dr. Daniel Eibach; Professor Dr. Egbert Tannich
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 299200240

Cryptosporidium is a widely distributed pathogen, causing prolonged and persistent diarrhoea and malnutrition among immunocompetent children and of severe diarrhoea in immunocompromised persons. Despite being among those pathogens with the highest attributable risk for diarrhoea in African children, Cryptosporidiosis is still substantially underdiagnosed and preventive measures are almost absent. Circulation of some Cryptosporidium subtypes seems to be restricted to humans or certain animal species, while others are transmitted across species between animals and humans. This host specificity is inadequately explained by genetic studies. Indeed, genomic studies of Cryptosporidium spp. lag far behind those on other enteric pathogens and related apicomplexan parasites. This study aims to disclose the predominant routes of transmission and genetic determinants of the parasite for specific hosts in order to identify populations at risk, to develop preventive measures and to determine potential drug targets. With a high Cryptosporidium prevalence and high heterogeneity of different genotypes in a very diverse host range, Sub-Saharan Africa is an excellent place to study the transmission between humans and animals, and to collect strains for further genome comparison. Results will not only be valuable for African countries, but can be applied to other transmission settings, in both developed and developing countries. The data will be collected at four African study sites, namely Gabon, Ghana, Madagascar and Tanzania. Comparable to an outbreak investigation, Cryptosporidium positive index children serve as starting points, tracing back the source of infection to their household/kindergarten contacts, animal contacts and water sources. All Cryptosporidium positive samples will be subtyped according to differences in the glycprotein60 gene. After oocyst purification, DNA will be extracted and sequenced on an Illumina MiSeq machine. A reference-based mapping and assembly of sequencing reads will be conducted. This will allow us to describe the genetic diversity of African Cryptosporidium isolates, to infer high-resolution transmission chains and to identify genetic determinants that define host-specificity. Previous studies showed that diarrhoeal disease has significant effects on the quality of life of affected individuals, their families and has profound social and financial consequences. Within this study, focus-group discussions will be conducted to learn about the cultural beliefs on diarrhoea causes, common prevention and treatment strategies and social implications of diarrhoeal disease. An extensive training programme for young African scientists will accompany the study. The present consortium, allows fostering of a sustainable scientific network spreading through Western-, Central- and Eastern Africa. A mentor system for young scientists and three training modules will help to initiate South-South as well as South-North collaborations

• DFG Programme: Research Grants
• International Connection: Gabon, Ghana, Madagascar, Tanzania
• Co-Investigators: Professor Dr. Steffen Borrmann; Dr. Denise Dekker; Dr. Benedikt Hogan; Ralf Krumkamp, Ph.D.; Dr. Gereon Schares; Kathrin Schuldt, Ph.D.; Dr. Thorsten Thye
• Cooperation Partners: Dr. Samwel Gesase; Oumou Maiga, Ph.D.; Professor Dr. Mamy Randria; Dr. Nimako Sarpong
• International Co-Applicants: Professor Ayola Akim Adegnika, Ph.D.; Professor Dr. John Lusingu; Professor Dr. Ellis Owusu-Dabo; Professor Dr. Raphael Rakotozandrindrainy