Browsing by Author "Malisa, Allen Lewis"

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Artemisinin combination therapies price disparity between government and private health sectors and its implication on antimalarial drug consumption pattern in Morogoro Urban District, Tanzania
(BMC Research Notes, 2012) Malisa, Allen Lewis; Kiriba, Deodatus
Universal access to effective treatments is a goal of the Roll Back Malaria Partnership. However, despite official commitments and substantial increases in financing, this objective remains elusive, as development assistance continue to be routed largely through government channels, leaving the much needed highly effective treatments inaccessible or unaffordable to those seeking services in the private sector. To quantify the effect of price disparity between the government and private health systems, this study have audited 92 government and private Drug Selling Units (DSUs) in Morogoro urban district in Tanzania to determine the levels, trend and consumption pattern of antimalarial drugs in the two health systems. A combination of observation, interviews and questionnaire administered to the service providers of the randomly selected DSUs were used to collect data. ALU was the most selling antimalarial drug in the government health system at a subsidized price of 300 TShs (0.18 US$). By contrast, ALU that was available in the private sector (coartem) was being sold at a price of about 10,000 TShs (5.9 US$), the price that was by far unaffordable, prompting people to resort to cheap but failed drugs. As a result, metakelfin (the phased out drug) was the most selling drug in the private health system at a price ranging from 500 to 2,000 TShs (0.29–1.18 US$). In order for the prompt diagnosis and treatment with effective drugs intervention to have big impact on malaria in mostly low socioeconomic malaria-endemic areas of Africa, inequities in affordability and access to effective treatment must be eliminated. For this to be ensued, subsidized drugs should be made available in both government and private health sectors to promote a universal access to effective safe and affordable life saving antimalarial drugs.
The evolutionary dynamics of genetic determinants of plasmodium falciparum resistance to sulfadoxine/pyrimethamine (sp) in South Eastern Tanzania
(Sokoine University of Agriculture, 2008) Malisa, Allen Lewis
This study reports a systematic follow up of genetic changes in the genes encoding the dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) enzymes of Plasmodium falciparum, in isolates from three rural districts of South-eastern Tanzania. The enzymes are the target of antimalarial drug, sulphadoxine- pyrimethamine (SP). The population-wide analysis of resistance mutations in the dhfr and dhps genes was applied to examine the influence of different drug use policies and their potential for the selection for SP resistance. A total of 47 244 bloodspot filter paper samples were collected from all individuals of all ages in randomly selected households in a series of annual surveys conducted between 2000 - 2006. Twenty percent (9 662) of all samples were found positive for P. falciparum infection on microscopy and hence were used for the genetic studies. DNA was extracted from P. falciparum-positxvz samples and dhfr and dhps genes were amplified by a nested polymerase chain reaction (PCR) and resistance conferring point mutations determined. Size polymorphisms at three sets of microsatellite loci linked to dhfr and three other sets of unlinked microsatellite loci were analysed by PCR amplification and electrophoresis on an automated sequencer. The influence of National treatment policy on the parasite reservoir was profound. The change of first line therapy from CQ to SP brought about highly significant increase of the frequencies of dhfr triple and dhps double mutants. Artemisinin-based combination therapy (ACT- SP+Artesunate) in Rufiji had a small and non-significant impact on the frequency of dhps double and dhfr triple mutant alleles, but significantly disrupted their association. Z)A/r-l inked microsatellites revealed high diversity around the dhfr sensitive alleles and significantly reduced diversity around mutant dhfr alleles. The majority of triple mutant alleles had one flanking microsatellite haplotype which has previously been shown to be derived from Southeast Asia, while the double mutant alleles had multiple haplotypes which were independently derived. Distribution of major lineages indicates that there is extensive genetic exchange among the geographic regions. Unlinked microsatellites confirmed the extent of allele sharing among the regions and revealed a major trend for reduced transmission intensity, which was apparently independent of the ACT intervention.
Population expansion but limited gene flow in kuhl's blue-spotted maskray along the Tanzanian coast
(2024) Nehemia, Alex; Shabani, Maulidi; Malisa, Allen Lewis
The blue-spotted maskray Neotrygon kuhlii (Müller & Henle, 1841) is a member of the Dasyatidae family of stingrays which grows slowly. Members of this group mature late and have a low fecundity rate. The ICUN Red List of Threatened Species lists N. kuhlii species as data deficient (DD) because information on its ecology and life history is not readily available. The purpose of this study was to determine the genetic diversity, demographic history and population structure of N. kuhlii, all of which are critical information for efforts aimed at conserving the species. The investigation was carried out along Tanzania's coastline using 595 base pairs of partial mitochondrial cytochrome oxidase subunit I (COI) sequence. The haplotype diversity ranged between 0.37 and 0.70 and nucleotide diversity between 0.11% and 0.50%. The findings show that samples from Unguja had higher mean molecular diversity indices than those from other sampling sites. Nonetheless, samples from Mafia and Unguja were found to have the largest effective population size. Genetic variations were found between the subpopulations under study, suggesting limited genetic connectivity among the studied subpopulations. The COI sequences of N. kuhlii from most subpopulations studied showed signs of past population expansion, which are typical for most Western Indian Ocean (WIO) fauna. The findings highlight the need for enhanced management and conservation strategies for N. kuhlii and other coastal stingray species in Tanzania, particularly in areas where sampling sites showed low levels of genetic diversity and effective population size.