TY - JOUR
T1 - The Potential Elimination of Plasmodium vivax Malaria by Relapse Treatment
T2 - Insights from a Transmission Model and Surveillance Data from NW India
AU - Roy, Manojit
AU - Bouma, Menno J.
AU - Ionides, Edward L.
AU - Dhiman, Ramesh C.
AU - Pascual, Mercedes
PY - 2013/1
Y1 - 2013/1
N2 - Background: With over a hundred million annual infections and rising morbidity and mortality, Plasmodium vivax malaria remains largely a neglected disease. In particular, the dependence of this malaria species on relapses and the potential significance of the dormant stage as a therapeutic target, are poorly understood. Methodology/Principal Findings: To quantify relapse parameters and assess the population-wide consequences of anti-relapse treatment, we formulated a transmission model for P. vivax suitable for parameter inference with a recently developed statistical method based on routine surveillance data. A low-endemic region in NW India, whose strong seasonality demarcates the transmission season, provides an opportunity to apply this modeling approach. Our model gives maximum likelihood estimates of 7.1 months for the mean latency and 31% for the relapse rate, in close agreement with regression estimates and clinical evaluation studies in the area. With a baseline of prevailing treatment practices, the model predicts that an effective anti-relapse treatment of 65% of those infected would result in elimination within a decade, and that periodic mass treatment would dramatically reduce the burden of the disease in a few years. Conclusion/Significance: The striking dependence of P. vivax on relapses for survival reinforces the urgency to develop more effective anti-relapse treatments to replace Primaquine (PQ), the only available drug for the last fifty years. Our methods can provide alternative and simple means to estimate latency times and relapse frequency using routine epidemiological data, and to evaluate the population-wide impact of relapse treatment in areas similar to our study area.
AB - Background: With over a hundred million annual infections and rising morbidity and mortality, Plasmodium vivax malaria remains largely a neglected disease. In particular, the dependence of this malaria species on relapses and the potential significance of the dormant stage as a therapeutic target, are poorly understood. Methodology/Principal Findings: To quantify relapse parameters and assess the population-wide consequences of anti-relapse treatment, we formulated a transmission model for P. vivax suitable for parameter inference with a recently developed statistical method based on routine surveillance data. A low-endemic region in NW India, whose strong seasonality demarcates the transmission season, provides an opportunity to apply this modeling approach. Our model gives maximum likelihood estimates of 7.1 months for the mean latency and 31% for the relapse rate, in close agreement with regression estimates and clinical evaluation studies in the area. With a baseline of prevailing treatment practices, the model predicts that an effective anti-relapse treatment of 65% of those infected would result in elimination within a decade, and that periodic mass treatment would dramatically reduce the burden of the disease in a few years. Conclusion/Significance: The striking dependence of P. vivax on relapses for survival reinforces the urgency to develop more effective anti-relapse treatments to replace Primaquine (PQ), the only available drug for the last fifty years. Our methods can provide alternative and simple means to estimate latency times and relapse frequency using routine epidemiological data, and to evaluate the population-wide impact of relapse treatment in areas similar to our study area.
UR - http://www.scopus.com/inward/record.url?scp=84873517905&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84873517905&partnerID=8YFLogxK
U2 - 10.1371/journal.pntd.0001979
DO - 10.1371/journal.pntd.0001979
M3 - Article
AN - SCOPUS:84873517905
SN - 1935-2727
VL - 7
JO - PLoS neglected tropical diseases
JF - PLoS neglected tropical diseases
IS - 1
M1 - e1979
ER -