Stothard's research and teaching is focused upon medical parasitology, with particular emphasis on neglected tropical diseases, most notably the epidemiology and control of schistosomiasis.

His work seeks to advance understanding of key parasites and intermediate hosts/vectors thereof, to better tailor future interventions in control and elimination of parasitic disease in not only humans, but to other animals including livestock, companion animals and wildlife.

Stothard's research relevance has prompted invites to present, chair and contribute to several World Health Organisation (WHO) expert committees including 'Guideline Review at Head Office/African Regional Office (Schistosomiasis)';[11] 'Roadmap for control of schistosomiasis: Schistosomiasis: progress report 2001–2011, strategic plan 2012–2020';[12] and 'Eliminating soil-transmitted helminthiases as a public health problem in children Progress report 2001−2010 and strategic plan 2011–2020'.

Stothard's multidisciplinary studies on Zanzibar, provided groundwork for subsequent international efforts towards elimination strategies in urogenital schistosomiasis.

Between 2004 and 2010 he was elected as honorary scientific secretary and executive board member at the Royal Society for Tropical Medicine and Hygiene.