Combining epidemiology with basic biology of sand flies, parasites, and hosts to inform leishmaniasis transmission dynamics and control

PLoS Pathogens

Caryn Bern¹  Orin Courtenay²  Matthew E. Rogers³  Nathan C. Peters⁴ 

[1] Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom;School of Life Sciences, University of Warwick, Coventry, United Kingdom;Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada;Zeeman Institute, University of Warwick, Coventry, United Kingdom

关键词: Parasitic diseases;    S;    flies;    Leishmaniasis;    Leishmania;    Infectious disease control;    Kala-azar;    Blood;    Vector-borne diseases;   

DOI  :  10.1371/journal.ppat.1006571

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Quantitation of the nonlinear heterogeneities in Leishmania parasites, sand fly vectors, and mammalian host relationships provides insights to better understand leishmanial transmission epidemiology towards improving its control. The parasite manipulates the sand fly via production of promastigote secretory gel (PSG), leading to the “blocked sand fly” phenotype, persistent feeding attempts, and feeding on multiple hosts. PSG is injected into the mammalian host with the parasite and promotes the establishment of infection. Animal models demonstrate that sand flies with the highest parasite loads and percent metacyclic promastigotes transmit more parasites with greater frequency, resulting in higher load infections that are more likely to be both symptomatic and efficient reservoirs. The existence of mammalian and sand fly “super-spreaders” provides a biological basis for the spatial and temporal clustering of clinical leishmanial disease. Sand fly blood-feeding behavior will determine the efficacies of indoor residual spraying, topical insecticides, and bed nets. Interventions need to have sufficient coverage to include transmission hot spots, especially in the absence of field tools to assess infectiousness. Interventions that reduce sand fly densities in the absence of elimination could have negative consequences, for example, by interfering with partial immunity conferred by exposure to sand fly saliva. A deeper understanding of both sand fly and host biology and behavior is essential to ensuring effectiveness of vector interventions.

【 授权许可】

CC BY