Nigerian Journal of Health and Biomedical Sciences

The AJOL site is currently undergoing a major upgrade, and there will temporarily be some restrictions to the available functionality.
-- Users will not be able to register or log in during this period.
-- Full text (PDF) downloads of Open Access journal articles will be available as always.
-- Full text (PDF) downloads of subscription based journal articles will NOT be available
We apologise for any inconvenience caused. Please check back soon, as we will revert to usual policy as soon as possible.

DOWNLOAD FULL TEXT Open Access  DOWNLOAD FULL TEXT Subscription or Fee Access

A rodent malarial model of Plasmodium berghei for the development of pyrimethamine and sulphadoxine-pyrimethamine resistant malaria in mice

BA Iwalokun, YA Olukosi, B Ogunsanwo, S Banjo, AS Afolabi, AA Aina


This study investigated the development of pyrimethamine (pyr) and sulphadoxine-pyrimethamine (S/P) resistance in Plasmodium berghei, a rodent parasite in mice using a serial technique (3.50 – 10mg/kg pyrimethamine) and a single treatment course approach with 125/6.25mg/kg S/P. The stability of resistance phenotypes, parasite pathogenic disposition and host leukocyte response were also investigated. The sequential and continuous increased-dose exposure of drug naïve parasites to pyrimethamine resulted in the development of two distinct resistant clone generations: PB10-1 and PB10-2 (3.5mg/kg pyr bypass clone) in 66.7% and 41.7% (P < 0.05) of drugged mice intraperitoneally challenged with 106 parasitized erythrocytes and producing slow ascending parasitaemia (20.4 ± 1.7 vs. 19.1 ± 3.8 %RBC; P > 0.05) on days 13 – 18 post inoculation that was significantly (P < 0.05) lower than the fulminating parasitaemia (27.3 ± 2.1%RBC) occurring on days 3 – 5 post inoculation in undrugged mice. The pyr resistance phenotype in PB10-1 and PB10-2 were observed to exhibit stability of > 10 and 3 – 5 weekly passages respectively in undrugged mice. The two clones further exhibited virulence disparity in their ability to cause significant (P < 0.05) increases in ALT (70.4 – 80.2 ± 3.4 – 3.8 vs. 31.8 ± 1.1 U/L) and AST (78.7 – 84.1 ± 3.1 – 3.7 vs. 38.6 ± 2.4 U/L) and reduction in total peripheral leukocyte count (3.2 – 4. 6 x 103 vs. 1.8 x 104 /mm3) when compared to the control. Resistance to S/P by 10%, 50% and 70% in sensitive, PB10-2 and PB10-1 clones was also observed, suggesting a non-requirement of pyr resistance for the development but necessity for the intensification of S/P resistance.

Keywords: Plasmodium berghei, Malaria, Sulphadoxine-pyrimethamine resistance

Nigerian Journal of Health and Biomedical Sciences Vol. 5 (2) 2006: 30-38

Full Text:

No subscription journal articles available during site upgrade.
AJOL African Journals Online