Genetic diversity in merozoite surface protein 1 of Plasmodium falciparum isolates from Igbogbo-bayeku, Lagos, Nigeria

Mutations in merozoite surface protein 1 (MSP1) serve as indicators of genetic diversity in Plasmodium falciparum population in a given area. Diversity in MSP1 gene of P. falciparum isolates in Igbogbo-Bayeku, a periurban settlement of Lagos, Nigeria was assessed. Malaria was diagnosed by microscopy and polymerase chain reaction (PCR). MSP1 gene polymorphisms were analyzed in P. falciparum-positive samples using allele-specific primers of the three families of MSP1 block 2. Of the 63 malaria cases, 34 (54%) were microscopic while 29 (46%) were sub-microscopic cases. The three MSP1 families were present in the P. falciparum isolates with RO33 being the most abundant (55; 87.3%). Thirteen distinct genotypes of MSP1 were observed. There were more polyclonal infections (40; 63.5%) than monoclonal infections (23; 36.5%). The multiplicity of infection (MOI) was 1.98 and the expected heterozygosity (He) was 0.64. Participants aged >8 years had significantly higher MOI (2.26±0.98) than those aged £ 8 years (1.78±0.83) (P=0.04). Polyclonal infections were similar in microscopic (23/39; 67.6%) and sub-microscopic infections (17/29; 58.6%) (P=0.46). However, polyinfections were more in microscopic (26/34; 76.5%) than in submicroscopic infections (15/29; 51.7%) (P=0.04). A high level of genetic diversity was observed in the P. falciparum isolates in this community-based study which is an indication of intense malaria transmission.&nbsp

Chloroquine-Chlorpheniramine Interaction In Human Malaria

The purpose of this study was to examine the effect of chloroquine-chlorpheniramine (CQ-CP) combination therapy on the efficacy and disposition of chloroquine (CQ) in acute uncomplicated malaria. A 3-day standard treatment with 25 mg CQ base per kilogram body weight alone or in combination with chlorpheniramine (CP) was orally administered to 17 semi-immune Nigerian children with Plasmodium falciparum parasitemia, attending the Massey Street Children's Hospital, Lagos, Nigeria. Parasitemia was determined on thick blood films stained with Giemsa, and treatment failures were established following the WHO classification for CQ resistance. Whole blood CQ concentrations were monitored at pre-determined intervals during the 28 days of follow-up using blood dried on filter-paper. Treatment with CQ-CP combination resulted in a shorter parasite clearance time (2.0 ± 0.5 d) & a higher cure rate (87.5%) compared to treatment with CQ alone (3.5 ± 0.5 d; 66.7%). CQ pharmacokinetic parameters: maximum drug concentration (Cmax) and the area under the first-moment drug-concentration-time curve (AUMC) were significantly increased (p < 0.01; p < 0.001 respectively) by CP administration while the time to achieve the peak was reduced in the presence of CP. We conclude that administration of CP increased CQ uptake as judged by an increase in the maximum concentration (Cmax) and a decrease in the time to attain the concentration (Tmax), as well as an increase in the area under the curve, which signifies increased systemic availability of CQ in the presence of CP. Nigerian Quarterly Journal of Hospital Medicine Vol.9, No.3 (1999) pp. 225-23

Investigation of the efficacy of two rapid assessment techniques (Optimal 1 and SD-Bioline) for the diagnosis of malaria in rural areas of Nigeria

We had previously studied the efficacy of three new techniques-Para Sight F, (PSF), Immunochromatographic Test (ICT) and Quantitative Buffy Coat (QBC) – as possible replacements for the time-consuming microscopy in the diagnosis of malaria. Two more rapid assessment techniques (the Optimal 1 and SD-BIOLINE) were recently introduced into Nigeria and claimed to exhibit high sensitivity and specificity. Optimal 1 was particularly claimed to distinguish between P falciparum, P. malariae, P ovale and P. vivax. We have in this work evaluated the efficacy of both the Optimal 1 and SD-Bioline in 240 patients from Ibafo and Magboro Communities in Obafemi-Owode LGA of Ogun State, Nigeria. Results showed that with regard to the detection of P. falciparum, Optimal 1 gave a sensitivity, specificity, positive and negative predictive values of 63.95%, 92.20%, 82.1% and 82.1% respectively, while the SD-Bioline gave 54.84%, 42.9%, 68.0% and 68.0% respectively. In retrospect, the sensitivities shown by 3 other techniques (ICT, PSF and QBC) investigated by us were 88.63, 89.95 and 87.6% respectively. Their specificities on the other hand were 94.60, 91.17, 94.70% respectively. The main advantage of the rapid Optimal 1 technique is that it was able to detect P. malariae which microscopy also detected in three patients. The SD-BIOLINE gave the worst comparative result and could not be recommended for use in Nigeria. This work in conclusion has shown that Optimal 1 could be useful in the rapid diagnosis of the various species of Plasmodium in Nigeria provided the patients could afford the test. (Af. J. of Clinical and Experimental Microbiology: 2003 4(1): 6-13