Vivax malaria and bacteraemia: A prospective study in Kolkata, India

Background: Falciparum malaria increases the risk for bacteraemia, whereas the relationship between vivax malaria and bacteraemia is not clear. Data from a prospective fever surveillance study in Kolkata, India were reanalysed for the potential association between Plasmodium vivax malaria and bacteraemia. Methods. Patients of all ages presenting with fever of three days or more to a project health outpost were invited to participate. A blood film and blood culture was performed on presentation. Treatment and referral were provided according to national guidelines. The case fraction and incidence of malaria, bacteraemia, and co-infection were calculated. Results: 3,371 participants were enrolled during a one-year study period, of whom 93/3,371 (2.8%) had malaria (89/93 [95.7%] Plasmodium vivax) and 256 (7.6%) bacteraemia. There were 154 malaria, 423 bacteraemia and 10 P. vivax-bacteremia coinfection episodes per 100,000/year. Among the malaria-bacteraemia co-infections, all were vivax malaria and 5/6 (83%) bacteria isolated were Gram-negative (one S. Typhi, one S. Paratyphi A, three other Gram-negative). Bacteraemia occurred in 6/89 (6.7% [95%CI: 3.1-13.9%]) of P. vivax cases versus 250/3,278 (7.6% [95% CI: 6.7-8.6%]) without Plasmodium infection (p=0.76). Conclusions: While an increased risk was not demonstrated, concomitant bacteraemia occurs frequently in vivax malaria in an area with a high background incidence of bacteraemia, and should be considered in cases of vivax malaria with severe manifestations.