CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2017, Vol. 35 ›› Issue (5): 434-439.

• Orginal Article • Previous Articles     Next Articles

Genotyping of merozoite surface protein 1 and 2 of imported Plasmodium falciparum in Wuhan City

Xi-shuai JIA, Shui-mao ZHOU*(), Yan YANG, Ming-xing XU, Kai WU   

  1. Wuhan Center for Disease Control and Prevention, Wuhan 430015, China
  • Received:2017-01-13 Online:2017-10-30 Published:2018-01-08
  • Contact: Shui-mao ZHOU E-mail:867494784@qq.com

Abstract:

Objective To identify the genotypes of merozoite surface protein 1 (MSP1) and merozoite surface protein 2 (MSP2) of imported Plasmodium falciparum in Wuhan. Methods Blood samples were collected from returnees infected with P. falciparum from endemic areas of Africa, from 2010 to 2015 in Wuhan City, and epidemiological data were collected. The Plasmodium falciparum DNA was extracted from the blood samples. Nested PCR was used to amplify gene fragments of MSP1 and MSP2. The constituent ratios of the allelic families, the frequencies of each allelic family in patients from different countries, and the association of different allelic families with disease severity were analyzed. Analysis of proportions of severe cases with different genotypes were analyzed with χ2 test. Results A total of 175 blood samples of patients with falciparum malaria were collected, which including 38 severe cases and 137 mild cases. Nested PCR for MSP1 allelic families K1, RO33 and MAD20 produced bands of 260-390, 270 and 150 bp, and MSP2 allelic families 3D7 and FC27 produced bands of 200-330 and 330-500 bp. A total of 175 patients with falciparum malaria were involved in this study, of whom 9 patients showed negative results for both MSP1 and MSP2 amplification. The MSP1 allelic families were detected in 136 patients, with a detection rate of 77.7%. The constituent ratios of MAD20, K1, RO33, MAD20 + K1, MAD20 + RO33, K1 + RO33, and MAD20 + K1 + RO33 were 5.1% (7/136), 37.5% (51/136), 20.6% (28/136), 5.9% (8/136), 4.4% (6/136), 16.9% (23/136), and 9.5% (13/136), respectively. The MSP2 allelic families were detected in 143 patients, with a detection rate of 81.7%. The constituent ratios of FC27, 3D7, and FC27 + 3D7 were 20.2% (29/143), 39.9% (57/143), and 39.9% (57/143), respectively. The MAD20 allelotype was predominantly from South Africa (10.5%, 4/38), the K1 was predominantly from South Africa (34.2%, 13/38), and the RO33 was predominantly from East Africa (2/7). The FC27 was not detected in East and North Africa, but was predominantly from South Africa (18.4%, 7/38). The 3D7 was predominantly from East Africa (4/7). The proportions of severe cases in the MAD20, K1, RO33, MAD20 + K1, MAD20 + RO33, K1 + RO33, and MAD20 + K1 + RO33 allelic families were 1/7, 19.6% (10/51), 32.1% (9/28), 1/8, 4/6, 13.0% (3/23), and 46.2% (6/13), respectively (P > 0.05 among MAD20 + RO33, MAD20 + K1 + RO33 and RO33; P < 0.05 for MAD20 + RO33, MAD20 + K1 + RO33 and RO33 versus the other four). The proportions of severe cases with 3D7, FC27, and FC27 + 3D7 were 19.3% (11/57), 20.7% (6/29), and 24.6% (14/57), respectively (P > 0.05). Conclusion There are three single allelic families of MSP1(MAD20, K1 and RO33) and four mixed allelic families in imported falciparum malaria in Wuhan, of which K1 and R033 are the dominant genotypes. There are three allelic families for MSP2(FC27, 3D7 and FC27 + 3D7), of which 3D7 has a higher frequency than FC27.

Key words: Plasmodium falciparum, Merozoite surface protein 1, Merozoite surface protein 2, Genotype

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