Sam was born in Zimbabwe and graduated as a veterinarian in Cuba in 1988 and joined the Ministry of Agriculture, Zimbabwe, as a Government Veterinary Officer. In 1989 moved to the National Veterinary Research Laboratory as a Veterinary Research Officer in the Parasitology section mainly dealing with diagnosis of livestock parasitic diseases and extension work.
In 1991, Sam was awarded a scholarship through DFID and left for the UK to pursue a Master of Veterinary Science (Parasitology) at the University of Liverpool (Liverpool School of Tropical Medicine). Immediately after completing his MVSc, he was offered a PhD Fellowship sponsored by Danish Development Agency on "Population genetics of the vector snails of trematodes in Zimbabwe" and registered with the University of Copenhagen. Sam completed his PhD in 1995, and joined the Faculty of Veterinary Science, University of Zimbabwe, as lecturer in Veterinary Parasitology and was promoted to the position of Senior lecturer in 1997. Sam became Deputy Dean of the Faculty in 1997 and Dean of Faculty in 2000-2007.
In 2003 Sam was appointed full Professor of Veterinary Parasitology. Sam’s research has been mainly on a variety of parasitic diseases of economic and public health importance and have developed a passion on "Neglected Parasitic Zoonoses" affecting the resource-poor communities in Africa which includes Taenia solium cysticercosis and trichinellosis. Currently, Sam is a WHO/FAO expert on neglected parasitic zoonoses.
In 1998 he was awarded the African Senior Fulbright Scholarship for 9 months to develop GIS models to predict the spread of schistosomiasis snails in China and Africa at the Faculty of Veterinary Medicine, Louisiana State University, USA. In recognition of his contribution to research in veterinary parasitology Sam was recipient in 2003 of the World Association for the Advancement of Veterinary Parasitology Peter Nansen Young Scientist Award in New Orleans, USA.
In 2007 Sam left University of Zimbabwe and joined the University of KwaZulu-Natal, SBCS, as a Professor in Parasitology and became the Academic Coordinator in 2009 before being appointed Head of School in 2010.