World Health Organisation (WHO)'s programme for Research and Training in Tropical Diseases (TDR) has recognized the following diseases in the TDR group. Malaria, Tuberculosis, Schistosomiasis, Filariasis, Onchocerciasis, Leishmaniasis, Chagas disease, African typanosomiasis, Leprosy and Dengue. The need to understand the socioeconomic factors in classifying the diseases as tropical was felt by TDR, because a major determinant for the burden of disease is poverty. In TDR's diseases the gap between the world's 20% poorest and 20% richest is wide. It is appalling to note that drug developers do not want to target diseases that primarily affect the poorest. SDTC would like to extend the philosophy in labeling a disease 'Tropical' depending upon the impact in a specific region of the world and loss of Disability-Adjusted Life Years (DALY) in global population in general. In that context we in India may have to include HIV, Cholera and Japanese encephalitis in Tropical Diseases.

Hunter's Tropical Medicine had earlier 4 criteria for covering an infectious disease under Tropical Diseases.
1. It occurs exclusively in tropical countries e.g. Malaria, Schistosomiasis, Dengue fever
2. It occurs much more commonly in developing countries e.g. TB, Amebiasis, measles.
3. It is caused by parasites that occur in temperate climate as well as tropics e.g. Trichomoniasis etc. and
4. It is transmitted by vectors or is a zoonotic disease e.g. Leptospirosis, Plague.