Molecular monitoring of resistant dhfr and dhps allelic haplotypes in Morogoro and Mvomero districts in south eastern Tanzania
Background: Resistance to the antimalarial drug sulfadoxine-pyrimethamine (SP) emerged in Plasmodium falciparum from
Asia in the 1960s and subsequently spread to Africa. In Tanzania, SP use as a national policy began in 1983 as a second line to chloroquine (CQ) for the treatment of uncomplicated malaria, until August 2001 when it was approved to replace CQ as a national first line.
Objective: The present study assesses the frequency of resistant dhfr and dhps alleles in Morogoro-Mvomero district in south eastern Tanzania and contrast their rate of change during 17 years of SP second line use against five years of SP first line use.
Methodology: Cross sectional surveys of asymptomatic infections were carried out at the end of rainy season during July-September of 2000, when SP was the national second line (CQ was the first line) and 2006 when SP was the national first line antimalarial treatment. Genetic analysis of SP resistance genes was carried out on 1,044 asymptomatic infections and the effect of the two policies on SP evolution compared.
Results: The frequency of the most resistant allele, the double dhps-triple dhfr mutant genotype, increased by only 1% during 17 years of SP second line use, but there was a dramatic increase by 45% during five years of SP first line use.
Conclusion: We conclude that National policy change from second line to first line SP, brought about an immediate shift in treatment practice and this in turn had a highly significant impact on drug pressure. The use of SP in specific programs only such as intermittent preventive treatment of infants (IPTi) and intermittent preventive treatment of pregnant women
(IPTp) will most likely reduce substantially SP selection pressure and the SP resistance alleles alike.
While African Health Sciences has been freely accessible online there have been questions on whether it is Open Access or not. We wish to clearly state that indeed African Health Sciences is Open Access. There are key issues regarding Open Access needing clarification for avoidance of doubt:
- 1. Henceforth, papers in African Health Sciences will be published under the CC BY (Creative Commons Attribution License) 4.0 International. See details on https://creativecomons.org/)
- 2. The copyright owners or the authors grant the 3rd party (perpetually and in advance) the right to disseminate, reproduce, or use the research papers in part or in full, format/medium as long as:
- No substantive errors are introduced in the process
- Attribution of authorship and correct citation details are given
- The referencing details are not changed.
Should the papers be reproduced in part, this must be clearly stated.
- 3. The papers will be freely and universally accessible online in an easily readable format such as XML in at least one widely recognized open access repository such as PUBMED CENTRAL.
B. ABRIDGED LICENCE AGREEMENT BETWEEN AUTHORS AND African Health Sciences
I submitted my manuscript to African Health Sciences and would like to affirm that:
1.0 I am authorized by my co-authors to enter into these arrangements.
2.0 I guarantee, on behalf of self and co-authors:
- That the paper is original, and has not been published in any other peer-reviewed journal; nor is it under consideration by other journal (s). It does not infringe existing copyright or any other person’s rights
- That we are/I am the sole author(s) of the paper and with authority to enter into this agreement. My granting rights to African Health Sciences is not in breach of any other obligation
- That the paper contains nothing unlawful, or libelous. Nor anything that would constitute a breach of contract, confidence or commitment given to secrecy, if published
- That I/we have taken care to ensure the integrity of the article.