ISSN 2736-173X
African Journal of Malaria and Tropical Diseases ISSN 4123-0981 Vol. 1 (4), pp. 020-029, December, 2013. © International Scholars Journals
Full Length Research Paper
An assessment of the difference between prevalence and frequency of antimalarial drug resistance using direct counting of haplotypes
*1Henry jobs, Kikwete Bomani2, Anna Bi1, Paul Salma3 and Yogi Monroe3
1Mzumbe University (MU), Department of Biological Sciences, Faculty of Science, Morogoro, Tanzania.
2Nelson Mandela African Institute of Science and Technology, Arusha, Tanzania.
3London School of Hygiene and Tropical Medicine, Pathogen Molecular Biology Unit, Department of Infectious Tropical
Diseases, School of Health Sciences - University of Surrey – Guildford, UK.
*Corresponding author. E-mail: [email protected]
Accepted 16 November, 2013
Abstract
Molecular monitoring of markers of anti-malarial drug resistance offers an affordable alternative to the in vivo method for the detection of resistance, and has the potential to guide public health policy in a timely manner. However, the optimal way of analyzing and reporting these data, particularly those emanating from areas of moderate to high malaria transmission, has never been fully explored or agreed upon, given the potential of being confounded by coinfections. By using large number of real field samples, we quantified the difference between prevalence and frequency when reporting field data on antimalarial drug resistance obtained by direct counting of haplotypes. Polymerase chain reaction (PCR) and sequence specific oligonucleotide probing was used to generate point mutations which were used to construct haplotypes. Results indicate that frequency underestimates haplotypes present at low levels while also amplifying haplotypes present at high levels; prevalence on the other hand behaved in a vice versa manner. Both prevalence and frequency are therefore essential, as each may have relevance in different contexts in high malaria transmission settings. Frequency is essential to gauge the impact of intervention on antimalarial drug resistance while prevalence may be more relevant when the aim is to determine parasite clearance.
Key words: Molecular markers, polymerase chain reaction (PCR) - sequence specific oligonucleotide probing (SSOP), prevalence, frequency.