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Multi-epitope chimeric antigen used as a serological marker to estimate Plasmodium falciparum transmission intensity in the border area of China-Myanmar

View Article: PubMed Central - PubMed

ABSTRACT

Background: Following the decline of malaria transmission in many countries and regions, serological parameters have become particularly useful for estimating malaria transmission in low-intensity areas. This study evaluated a novel serological marker, Malaria Random Constructed Antigen-1 (M.RCAg-1), which contains 11 epitopes from eight Plasmodium falciparum antigens, as a tool for assessing malaria transmission intensity along the border area of China-Myanmar.

Method: Serum from Plasmodium falciparum and P. vivax patients was used to detect the properties of M.RCAg-1 and antibody responses. Cross-sectional surveys were conducted at the China-Myanmar border and in Hainan province in 2012 and 2013 using cluster sampling. Filter blood spot papers were collected from all participants. Antibodies against M.RCAg-1 were detected using indirect ELISA. The Mann–Whitney test and Spearman’s rank correlation test were performed to analyze antibody data. P. falciparum malaria transmission intensity was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR).

Results: M.RCAg-1 was well-recognized by the naturally acquired anti-malaria antibodies in P. falciparum patients and had very limited cross-reactivity with P. vivax infection. The total amount of IgG antibodies was decreased with the decrease in parasitemia after taking medication and lasted several weeks. In a population survey, the antibody levels were higher in residents living close to the China-Myanmar border than those living in non-epidemic areas (P < 0.0001), but no significant difference was observed between residents from Hainan and non-epidemic areas. The calculated SCR was 0.0128 for Jieyangka, 0.004 for Susuzhai, 0.0047 for Qiushan, and 0.043 for Kayahe. The estimated exposure rate obtained from the anti-M.RCAg-1 antibody level correlated with traditional measures of transmission intensity derived from altitude.

Conclusion: Our study demonstrates that M.RCAg-1 is potentially useful as a serological indicator of exposure to P. falciparum malaria, especially for malaria surveillance in low transmission areas.

Electronic supplementary material: The online version of this article (doi:10.1186/s40249-016-0194-x) contains supplementary material, which is available to authorized users.

No MeSH data available.


The information of research sites. a the specific locations of villages selected in this study. One village (Jieyangka) in Laza, Myanmar, three villages (Susuzhai, Qiushan and Kayahe) in Yunnan province, China. b the altitudes of three villages in Yunnan. c the annual average temperature and annual rainfall in the three villages selected in Yunnan
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Fig1: The information of research sites. a the specific locations of villages selected in this study. One village (Jieyangka) in Laza, Myanmar, three villages (Susuzhai, Qiushan and Kayahe) in Yunnan province, China. b the altitudes of three villages in Yunnan. c the annual average temperature and annual rainfall in the three villages selected in Yunnan

Mentions: This study comprised two cross-sectional surveys conducted in the border area of China-Myanmar and Hainan province of China. The border area in Yunnan province with Myanmar [27, 28] was the most challenging area in which to achieve the final goal of a malaria-free China by 2020 as planned by the Chinese Center for Disease Control and Prevention. The malaria transmission intensity in these areas, especially Pf malaria, has decreased significantly in recent years because of the implementation of malaria control strategies. Only 15 indigenous Pf malaria cases were reported in Yunnan province in 2012–2013 [29]; thus, the sensitivity of traditional methods, such as EIR and parasite prevalence, is limited in this area. However, the number of indigenous Pf malaria cases was much greater in Laza, Myanmar, than Yunnan province in China; 415 Pf malaria cases were reported in 2012–2013 [30]. One village (Jieyangka) in Laza was selected; considering that malaria transmission is influenced by altitude, three villages at various altitudes in Yunnan were selected: Susuzhai (altitude 1 660 m), Qiushan (1 160 m), and Kayahe (210 m). The climates of these villages, such as temperature and rainfall, also vary (Fig. 1).Fig. 1


Multi-epitope chimeric antigen used as a serological marker to estimate Plasmodium falciparum transmission intensity in the border area of China-Myanmar
The information of research sites. a the specific locations of villages selected in this study. One village (Jieyangka) in Laza, Myanmar, three villages (Susuzhai, Qiushan and Kayahe) in Yunnan province, China. b the altitudes of three villages in Yunnan. c the annual average temperature and annual rainfall in the three villages selected in Yunnan
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5015264&req=5

Fig1: The information of research sites. a the specific locations of villages selected in this study. One village (Jieyangka) in Laza, Myanmar, three villages (Susuzhai, Qiushan and Kayahe) in Yunnan province, China. b the altitudes of three villages in Yunnan. c the annual average temperature and annual rainfall in the three villages selected in Yunnan
Mentions: This study comprised two cross-sectional surveys conducted in the border area of China-Myanmar and Hainan province of China. The border area in Yunnan province with Myanmar [27, 28] was the most challenging area in which to achieve the final goal of a malaria-free China by 2020 as planned by the Chinese Center for Disease Control and Prevention. The malaria transmission intensity in these areas, especially Pf malaria, has decreased significantly in recent years because of the implementation of malaria control strategies. Only 15 indigenous Pf malaria cases were reported in Yunnan province in 2012–2013 [29]; thus, the sensitivity of traditional methods, such as EIR and parasite prevalence, is limited in this area. However, the number of indigenous Pf malaria cases was much greater in Laza, Myanmar, than Yunnan province in China; 415 Pf malaria cases were reported in 2012–2013 [30]. One village (Jieyangka) in Laza was selected; considering that malaria transmission is influenced by altitude, three villages at various altitudes in Yunnan were selected: Susuzhai (altitude 1 660 m), Qiushan (1 160 m), and Kayahe (210 m). The climates of these villages, such as temperature and rainfall, also vary (Fig. 1).Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Following the decline of malaria transmission in many countries and regions, serological parameters have become particularly useful for estimating malaria transmission in low-intensity areas. This study evaluated a novel serological marker, Malaria Random Constructed Antigen-1 (M.RCAg-1), which contains 11 epitopes from eight Plasmodium falciparum antigens, as a tool for assessing malaria transmission intensity along the border area of China-Myanmar.

Method: Serum from Plasmodium falciparum and P. vivax patients was used to detect the properties of M.RCAg-1 and antibody responses. Cross-sectional surveys were conducted at the China-Myanmar border and in Hainan province in 2012 and 2013 using cluster sampling. Filter blood spot papers were collected from all participants. Antibodies against M.RCAg-1 were detected using indirect ELISA. The Mann–Whitney test and Spearman’s rank correlation test were performed to analyze antibody data. P. falciparum malaria transmission intensity was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR).

Results: M.RCAg-1 was well-recognized by the naturally acquired anti-malaria antibodies in P. falciparum patients and had very limited cross-reactivity with P. vivax infection. The total amount of IgG antibodies was decreased with the decrease in parasitemia after taking medication and lasted several weeks. In a population survey, the antibody levels were higher in residents living close to the China-Myanmar border than those living in non-epidemic areas (P < 0.0001), but no significant difference was observed between residents from Hainan and non-epidemic areas. The calculated SCR was 0.0128 for Jieyangka, 0.004 for Susuzhai, 0.0047 for Qiushan, and 0.043 for Kayahe. The estimated exposure rate obtained from the anti-M.RCAg-1 antibody level correlated with traditional measures of transmission intensity derived from altitude.

Conclusion: Our study demonstrates that M.RCAg-1 is potentially useful as a serological indicator of exposure to P. falciparum malaria, especially for malaria surveillance in low transmission areas.

Electronic supplementary material: The online version of this article (doi:10.1186/s40249-016-0194-x) contains supplementary material, which is available to authorized users.

No MeSH data available.