Active v. passive surveillance for malaria in remote tribal belt of Central India: Implications for malaria elimination

Abstract

Balaghat district in Central India is characterized by perennial malaria transmission. In this study, we have estimated malaria parasite rates by microscopic examination of blood smears by conducting active (ACD) and passive surveillance (PCD) in the villages of Baihar community health center (CHC) during January 2012–December 2012. Comparison of the results of two methods revealed that ACD (active case detection) in villages provides relatively large numbers of malaria positive cases (1408/3601) as compared to PCD (passive case detection) at CHC (139/2743) (OR 12.03, 95% CI, 9.97–14.57, p < 0.0001). Similarly, large numbers of Plasmodium falciparum cases (1194) were found (SFR, 33.2%) in villages, while only 98 P. falciparum cases (SFR, 3.6%) were found at CHC (OR 13.39, 95% CI, 10.80–16.73, p < 0.0001). Likewise, Plasmodium vivax were 211 (SVR, 5.9%) in villages by ACD (OR 4.1, 95% CI, 2.91–5.9, p < 0.0001), while only 41 P. vivax (SVR, 1.5%) were found at CHC. In this cross-sectional study, we discussed the potential role of ACD in strengthening of surveillance for high coverage. For malaria elimination initiative, a surveillance system must be more sensitive than PCD along with effective tools for vector control to target high-risk population who are not visiting the health facility and seed transmission to the surrounding population. The study highlights the substantial difference in the malaria positivity rate by two methods in difficult and hard-to-reach areas and recommendations are made to understand how best to deploy ACD methods in the pursuit of malaria elimination.

Graphical abstract showing the month wise active and passive malaria prevalence.

Keywords:

• Active surveillance
• Passive surveillance
• Malaria
• Plasmodium falciparum
• Plasmodium vivax
• Central India
• Tribal
• Microscopic examination

Acknowledgements

We thank all the study participants and their relatives for providing the informed consent. We thank all the project staff at the Community Health Centre, Baihar, Balaghat, for their help and support. Thanks are also due to Dr. Ravendra Sharma, Scientist D, NIRTH for help in statistical analysis.