India’s approach to eliminating Plasmodium falciparum malaria: A modeling perspective

Approximately one-third of the world’s population that is at risk to malaria lives in India. Plasmodium falciparum, a deadly form of malaria, accounts for about 50% percent of the cases there. Since 1940s India has used a number of programmes to combat the disease with variable success. Since 1998 the total numbers of malaria cases, and in particular P. falciparum cases, have been steadily declining, making India one of the success stories among the countries supported by the Roll Back Malaria Partnership (RBM). This article considers India’s P. falciparum control methods from the perspective of a Ross-MacDonald type model. The model is fitted to the P. falciparum cases in India over the period 1983-2009. We focus on the disease reproduction number as being a measure of success of programs. Before the start of RBM measures the disease reproduction number was R0 = 1.00732, meaning that the incidence of disease was increasing among the population. With the new control measures Rc = 0.999457, suggesting that P. falciparum cases may be declining to zero but extremely slowly. The model here projects 0.734 million cases of P. falciparum malaria for 2010, down from 1.14 million cases in 2000. This impressive 36% decrease falls somewhat short of the RBM’s goal of 50% reduction. However, a sensitivity analysis of the disease reproduction number done here suggests that India’s control programs do apply controls at the most critical points in the disease cycle; namely, mosquito biting rates, mosquito mortality, and treatment of infected humans. This suggests that as more resources become available, they should be applied to strengthening these controls. The novelty here is in fitting recent data on malaria from India to derive current values of the disease reproduction number.