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Open Access Highly Accessed Opinion

Helminth-infected patients with malaria: a low profile transmission hub?

Mathieu Nacher

Author Affiliations

Epidémiologie des Parasitoses et Mycoses Tropicales, EA3593, Université des Antilles et de la Guyane, Campus Saint Denis, Cayenne, 97300, Guyane Française

Centre d’Investigation Clinique Epidémiologie Clinique CIE INSERM 802, Centre Hospitalier de Cayenne, Cayenne, Guyane Française

Malaria Journal 2012, 11:376  doi:10.1186/1475-2875-11-376

Published: 15 November 2012

Abstract

Eclipsed by the debates about malaria incidence and severity in individual patients, malaria transmission in helminth-infected persons has so far received very little attention. Studies in humans have shown increased malaria incidence and prevalence, and a trend for a reduction of symptoms in patients with malaria. This suggests that such patients could possibly be less likely to seek treatment thus carrying malaria parasites and their gametocytes for longer durations, therefore, being a greater potential source of transmission. In addition, in humans, a study showed increased gametocyte carriage, and in an animal model of helminth-malaria co-infection, there was increased malaria transmission. These elements converge towards the hypothesis that patients co-infected with worms and malaria may represent a hub of malaria transmission. The test of this hypothesis requires verifying, in different epidemiological settings, that helminth-infected patients have more gametocytes, that they have less symptomatic malaria and longer-lasting infections, and that they are more attractive for the vectors. The negative outcome in one setting of one of the above aspects does not necessarily mean that the other two aspects may suffice to increase transmission. If it is verified that patients co-infected by worms and malaria could be a transmission hub, this would be an interesting piece of strategic information in the context of the spread of anti-malarial resistance and the malaria eradication attempts.

Keywords:
Malaria; Worms; Coinfection; Immunomodulation; Anemia; Asymptomatic; Transmission; Vector