Sequestrated Plasmodium falciparum parasites in human infections: different genotype distribution in placental as compared to that in the peripheral circulation

Abstract

ABSTRACT

Introduction: In regions highly endemic for malaria, the prevalence of placental malaria ranges from 30% to

60% and has been associated with increased risk of adverse infant outcomes, particularly in primigravidae.

Objectives: The study was conducted on mothers after delivery to detect sequestered Plasmodium

falciparum (P. falciparum) parasite by using PCR based genotyping technique.

Materials and methods: The study was conducted during the period of January 2009 to September 2011.

5ml of venous and placental blood were obtained from 75 mothers after delivery, attended to Omdurman

Maternity Hospital. Genomic DNA was extracted from peripheral and placental blood samples using

modified phenol chloroform technique. The msp-1 allele (MAD20,) and msp-2 allele A1, A2, B1 and B2,

plasmodium falciparum primers were used for PCR. The PCR product was analyzed on 1.5% Agarose gel

and visualized by gel documentation system after ethidium bromide staining.

Results: The results revealed that the overall malaria detection rate in peripheral blood and placental blood

using ICT was 10.7%. With the PCR (msp-1 alleles) the detection rate of malaria in peripheral blood was

found to be 9.3%, while in placental blood the same technique showed a detection rate of 10.7%. For PCR

(msp-2 alleles), the detection rate of malaria in peripheral blood was 12%, while in placental blood the same

technique showed detection rate of 21.3% malaria.

Conclusion: In the vast majority of cases, some sequestered genotypes remain hidden, undetected in the

peripheral circulation, indicating that analysis of peripheral parasites generates a partial picture of a P.

falciparum infection. The cord blood must be collected from the umbilical cord to detected placental P.

falciparum infection particularly in primigravidae