Four decades of epidemiological data reveal trajectories towards malaria elimination in Kheda district (Gujarat), western part of India

Abstract

Background: Malaria is a main public health problem in India and was so particularly in the state of Gujarat in the western part of the country. This study assesses the effects of various interventions on malaria cases using data from the last 33 years (1987-2019).

Methods: Here we have analysed 33 years of malaria epidemiological data from a malaria clinic in Kheda district in Gujarat. The data were digitised yearly and monthly, age-wise and gender-wise, and descriptive analysis was performed to assess the effects of several interventions on malaria burden.

Results: During 1987-2019, our clinic diagnosed 5466 Plasmodium vivax and 4732 P. falciparum malaria cases. Overall, there was a declining trend in malaria cases except for the years 1991, 1994, 2004 and 2005. The year 2004 especially witnessed an epidemic in Kheda as well as throughout Gujarat. Malaria infections were most common (40%) among the 21-40 years age group. Fever was the most common symptom in all age groups.

Interpretation: Introduction of revised drug policy and improved surveillance technique (rapid diagnosis kits) have strengthened the diagnosis and treatment of malaria in the district. Use of pyrethroid in indoor residual insecticide spray has also strengthened vector control. Among the various interventions used, long-lasting insecticide nets and introduction of artemisinin-based combination therapy have played significant roles in controlling malaria cases. A more drastic decline in P. falciparum cases versus P. vivax is evident, but the latter persists in high proportions and therefore new tools for malaria control will be needed for elimination.

Keywords: epidemiology; indices of health and disease and standardisation of rates; malaria.

Figure 1

Study area. NIMR, National Institute of Malaria Research.

Figure 2

Malaria dynamics from 1987 to 2019: malaria clinic cases. BSE, blood slide examination; DDT, dichloro-diphenyl-trichloroethane; IRS, indoor residual insecticide spray; LLIN, long-lasting insecticide net; LTN, long-lasting treated nets; AS, Artesunate sulfadoxine; P-pyrimethamine; Pf, Plasmodium falciparum; Pv, Plasmodium vivax.

Figure 3

Seasonality in Plasmodium vivax (Pv) cases in three spans of years: clinic data Fig.3 A, C, E and programme data Fig.B, D, F.

Figure 4

Seasonality in Plasmodium falciparum (Pf) cases in three spans of years: clinic data Fig. A, C, E and programme data Fig.B, D, F.

Figure 5

Age (Fig. C, D) and gender (Fig. A, B) distribution of malaria cases from 2004 to 2019.