Epidemiology of Plasmodium spp. gametocyte carriage in Delhi, India

Malaria transmission is fuelled by the development stages called gametocytes. Prevalence, patterns, and determinants of gametocyte carriage, a silent and understudied public health issue, were evaluated in Delhi, India. Between August 2022 and September 2023, a cross-sectional study was conducted at a reference hospital. Gametocyte detection was performed by light microscopy. Of the 4259 febrile patients included, gametocytes were found at a prevalence of 1.3 %, with a predominance of P. vivax (78.6 %). Higher risks of P. falciparum gametocyte carriage were found in individuals with increased levels of platelet count -PCT (aOR = 10.66 to 12.82, p < 0.05), C-reactive protein-CRP (aOR = 4.11 to 6.16, p < 0.05), and red blood cells-RBC (aOR = 6.78, p = 0.005), whereas increased haemoglobin (Hb) was protective (aOR = 0.56, p = 0.002). Similar patterns were found for P. vivax gametocyte carriage, in addition to the effect of the malaria transmission period (aOR = 2.89, p = 0.01). This study pinpoints a low Plasmodium spp. gametocyte carriage, with a consistent influence of CRP, PCT, Hb, and malaria transmission. These findings might provide baseline information for targeting gametocyte carriers to block malaria transmission in the area.