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Elimination of Plasmodium falciparum in an area of multi-drug resistance.

Lwin KM, Imwong M, Suangkanarat P, Jeeyapant A, Vihokhern B, Wongsaen K, Snounou G, Keereecharoen L, White NJ, Nosten F - Malar. J. (2015)

Bottom Line: The chemoprevention was generally well tolerated.From June to October 2012 (rainy season) the number of clinical episodes of P. falciparum was six times lower (46), than during the same period in the previous year (290).Mass drug administration with dihydroartemisinin-piperaquine may be an effective strategy to eliminate P. falciparum rapidly where multi-drug resistance is present.

View Article: PubMed Central - PubMed

Affiliation: Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand. drkhin_mg_lwin@shoklo-unit.com.

ABSTRACT

Background: Resistance to the artemisinin derivatives in Plasmodium falciparum has emerged in Cambodia and is now spreading throughout South-East Asia. The rapid elimination of P. falciparum seems to be the only viable option to avoid a public health disaster but this is difficult because even in low transmission settings many residents have asymptomatic parasitaemias.

Methods: In response to a large number of malaria cases reported in three remote villages on the Thai-Myanmar border where malaria is endemic and the disease is seasonal, surveys were conducted using an ultra-sensitive qPCR assay (LOD 22 parasites per mL). In one of the villages where it was feasible, mass anti-malarial drug administration was proposed to the population as a potential solution, and this was adopted.

Results: In the three villages 204/356 (57.3 %), 212/385 (55.1 %) and 195/286 (68.2 %) of the resident populations were positive by qPCR (approximately one-third P. falciparum and two-thirds P. vivax). Of those positive for P. falciparum 62 % carried single point mutations in the P. falciparum kelch protein (a marker of artemisinin resistance). In one of the villages 217 of 674 inhabitants received at least one dose of dihydroartemisinin-piperaquine chemoprevention in June 2012, 155 (71.4 %) received two consecutive months, and 98 (45.2 %) received three treatment doses. The chemoprevention was generally well tolerated. The sub-microscopic reservoir of P. falciparum malaria was eliminated during the six-month follow-up period (prevalence fell from 7 to 0 %); P. vivax malaria persisted (prevalence fell from 35 to 8 %). From June to October 2012 (rainy season) the number of clinical episodes of P. falciparum was six times lower (46), than during the same period in the previous year (290).

Conclusion: Mass drug administration with dihydroartemisinin-piperaquine may be an effective strategy to eliminate P. falciparum rapidly where multi-drug resistance is present.

No MeSH data available.


Related in: MedlinePlus

Prevalence of malaria in the 96 participants who received the full course of DP. Blue: P. falciparum, Red: P. vivax, Green: indeterminate species.
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Fig2: Prevalence of malaria in the 96 participants who received the full course of DP. Blue: P. falciparum, Red: P. vivax, Green: indeterminate species.

Mentions: The results of the post-chemoprevention surveys conducted in June, July, August, and December 2012 in WLM indicated an overall reduction in the prevalence of malaria in the population (Table 5). In July, one of the five P. falciparum cases was in a participant who had received DP in June and who was negative by PCR in August and December. The remaining P. falciparum cases (four in July and five in August) were all in people who had not previously received DP. Eight of the participants to the June 2012 survey were already positive by qPCR in the December 2011 survey (i.e. 6 months earlier), five with mixed infections and three with P. falciparum. Of those with mixed infections in December 2011, two had P. vivax, two mixed infections and one P. falciparum in the June 2012 survey. Of the three remaining P. falciparum infections of December 2011, two had P. vivax and one was negative in June 2012 (Table 6). In the sub-group of 96 people (83 adults and 13 children) who received the three courses of DP and also provided a venous sample at each survey, the proportion of P. falciparum infections declined from 5.2 % (5/96) in June to nil in July, August and December while the proportion of P. vivax infections declined from 27.1 % (26/96) to 2.1 % (8/96) in July, 2.1 % (8/96) in August and was 13.5 % (13/96) in December (Fig. 2). The plasmodial species could not be determined in 18.8 % (18/96) in June, 8.3 % (8/96) in July, 12.5 % (12/96) in August and 9.4 % (9/96) in December 2012. During the period from June to October 2012 (rainy season) the number of clinical episodes of P. falciparum detected by the malaria post was over six times lower (46) than in the same period of the previous year (290).Fig. 2


Elimination of Plasmodium falciparum in an area of multi-drug resistance.

Lwin KM, Imwong M, Suangkanarat P, Jeeyapant A, Vihokhern B, Wongsaen K, Snounou G, Keereecharoen L, White NJ, Nosten F - Malar. J. (2015)

Prevalence of malaria in the 96 participants who received the full course of DP. Blue: P. falciparum, Red: P. vivax, Green: indeterminate species.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4537587&req=5

Fig2: Prevalence of malaria in the 96 participants who received the full course of DP. Blue: P. falciparum, Red: P. vivax, Green: indeterminate species.
Mentions: The results of the post-chemoprevention surveys conducted in June, July, August, and December 2012 in WLM indicated an overall reduction in the prevalence of malaria in the population (Table 5). In July, one of the five P. falciparum cases was in a participant who had received DP in June and who was negative by PCR in August and December. The remaining P. falciparum cases (four in July and five in August) were all in people who had not previously received DP. Eight of the participants to the June 2012 survey were already positive by qPCR in the December 2011 survey (i.e. 6 months earlier), five with mixed infections and three with P. falciparum. Of those with mixed infections in December 2011, two had P. vivax, two mixed infections and one P. falciparum in the June 2012 survey. Of the three remaining P. falciparum infections of December 2011, two had P. vivax and one was negative in June 2012 (Table 6). In the sub-group of 96 people (83 adults and 13 children) who received the three courses of DP and also provided a venous sample at each survey, the proportion of P. falciparum infections declined from 5.2 % (5/96) in June to nil in July, August and December while the proportion of P. vivax infections declined from 27.1 % (26/96) to 2.1 % (8/96) in July, 2.1 % (8/96) in August and was 13.5 % (13/96) in December (Fig. 2). The plasmodial species could not be determined in 18.8 % (18/96) in June, 8.3 % (8/96) in July, 12.5 % (12/96) in August and 9.4 % (9/96) in December 2012. During the period from June to October 2012 (rainy season) the number of clinical episodes of P. falciparum detected by the malaria post was over six times lower (46) than in the same period of the previous year (290).Fig. 2

Bottom Line: The chemoprevention was generally well tolerated.From June to October 2012 (rainy season) the number of clinical episodes of P. falciparum was six times lower (46), than during the same period in the previous year (290).Mass drug administration with dihydroartemisinin-piperaquine may be an effective strategy to eliminate P. falciparum rapidly where multi-drug resistance is present.

View Article: PubMed Central - PubMed

Affiliation: Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand. drkhin_mg_lwin@shoklo-unit.com.

ABSTRACT

Background: Resistance to the artemisinin derivatives in Plasmodium falciparum has emerged in Cambodia and is now spreading throughout South-East Asia. The rapid elimination of P. falciparum seems to be the only viable option to avoid a public health disaster but this is difficult because even in low transmission settings many residents have asymptomatic parasitaemias.

Methods: In response to a large number of malaria cases reported in three remote villages on the Thai-Myanmar border where malaria is endemic and the disease is seasonal, surveys were conducted using an ultra-sensitive qPCR assay (LOD 22 parasites per mL). In one of the villages where it was feasible, mass anti-malarial drug administration was proposed to the population as a potential solution, and this was adopted.

Results: In the three villages 204/356 (57.3 %), 212/385 (55.1 %) and 195/286 (68.2 %) of the resident populations were positive by qPCR (approximately one-third P. falciparum and two-thirds P. vivax). Of those positive for P. falciparum 62 % carried single point mutations in the P. falciparum kelch protein (a marker of artemisinin resistance). In one of the villages 217 of 674 inhabitants received at least one dose of dihydroartemisinin-piperaquine chemoprevention in June 2012, 155 (71.4 %) received two consecutive months, and 98 (45.2 %) received three treatment doses. The chemoprevention was generally well tolerated. The sub-microscopic reservoir of P. falciparum malaria was eliminated during the six-month follow-up period (prevalence fell from 7 to 0 %); P. vivax malaria persisted (prevalence fell from 35 to 8 %). From June to October 2012 (rainy season) the number of clinical episodes of P. falciparum was six times lower (46), than during the same period in the previous year (290).

Conclusion: Mass drug administration with dihydroartemisinin-piperaquine may be an effective strategy to eliminate P. falciparum rapidly where multi-drug resistance is present.

No MeSH data available.


Related in: MedlinePlus