JAC Advance Access published online on August 5, 2008
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkn299
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Original research |
Accumulation of CVIET Pfcrt allele of Plasmodium falciparum in placenta of pregnant women living in an urban area of Dakar, Senegal
1 Unité d’Immunologie, Institut Pasteur de Dakar, Sénégal 2 Unité Immunologie Moléculaire des Parasites, CNRS URA 2581, Institut Pasteur de Paris, France 3 Hôpital Roi Baudouin de Guediawaye, Dakar, Sénégal 4 Unité mère-enfant, Institut Recherche et Développement, Dakar, Sénégal
Received 22 November 2007; returned 26 February 2008; revised 10 June 2008; accepted 29 June 2008
* Corresponding author. Present address. Vascular Immunology Unit, Faculty of Medicine, University of Sydney, Medical Foundation Building (K25), 92-94 Parramatta Rd, Camperdown, NSW 2042, Australia. Tel: +61-2-9036-3222; Fax: +61-2-9036-3177; E-mail: rjambou{at}med.usyd.edu.au
Objectives: Chemoprophylaxis is recommended during pregnancy to reduce the risk of placental infection. However, in areas with increasing drug resistance, it can trigger selection of resistant parasites in the placenta and increase the frequency of placental malaria. The objective of this study was to analyse the selection of drug-resistant parasites in the placenta in an area where chloroquine was still recommended as prophylaxis.
Patients and methods: We analysed the polymorphism of parasites from matched placental and venous blood samples at the time of delivery from women in Dakar. Polymorphism of the isolates was studied using nested PCR typing of MSA1 and MSA2 genes, and full sequence of PfCRT exon 2.
Results: Of 692 women recruited at delivery, 72 had placental malaria. Two Pfcrt exon 2 genotypes were found, and 86% of the placentas had monoallelelic CVIET infection compared with 39% that had peripheral blood infection. Mixed parasite populations of CVIET/CVMNK occurred in 53% of the peripheral blood samples but only in 7% of the infected placentas. This selection of CVIET in placenta was not related to a decreased polymorphism of the parasites, as a large diversity of MSA1 and MSA2 was found in both placenta and venous blood. This diversity confirms that a multiplicity of circulation isolates can occur at low parasite transmission. msp1 and msp2 genotyping revealed mostly distinct populations of parasites in venous and placental blood.
Conclusions: These data suggest that, even in low transmission areas, diverse parasite populations can accumulate in the placenta during pregnancy despite strong selection at the PfCRT locus due to chemoprophylaxis with chloroquine.
Key Words: pregnancy , malaria , P. falciparum , chloroquine resistance
Present address. School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore, Singapore.
Present address. Institut Pasteur de guadeloupe B.P. 484, 97165 Pointe à Pitre Cedex, France.
¶ Present address. Unité d’Immunologie Moléculaire des Parasites, Institut Pasteur Paris, 25 Rue du Dr Roux, 75015 Paris, France.
Present address. Dispensaire Roi Baudouin de Guédiawaye, Dakar, Sénégal.
|| Present address. Unité d’Epidémiologie, Institut Pasteur de Dakar, B.P. 220, Dakar, Sénégal.
# Present address. Unité de Recherche Santé de la Mère et de l’Enfant, Institut de Recherche Développement, Dakar, Sénégal.
** Present address. Department of Infectious Diseases and CTEGD, University of Georgia, 500 DW Brooks Drive, N326 Paul Coverdell Center, Athens, GA 30602, USA.
Present address. Laboratoire Anatomo-pathlogie, Institut Pasteur de Dakar, B.P. 220, Dakar, Sénégal.