Genetic diversity of Plasmodium falciparum isolates based on MSP-1 and MSP-2 genes from Kolla-Shele area, Arbaminch Zuria District, southwest Ethiopia.

BACKGROUND: The genetic diversity of Plasmodium falciparum has been extensively studied in various countries. However, limited data are available from Ethiopia. This study was conducted to evaluate the extent of genetic diversity of P. falciparum in Kolla-Shele, in the southwest of Ethiopia. METHODS: A total of 88 isolates from patients with uncomplicated P. falciparum attending Kolla-Shele Health Centre was collected from September to December, 2008. After extraction of DNA by Chelex method, the samples were genotyped by using nested-PCR of msp1 (block 2) and msp2 (block 3) including their allelic families: K1, MAD20, RO33 and FC27, 3D7/IC1, respectively. RESULTS: Allelic variation in both msp1 and msp2 were identified in the 88 blood samples. For msp1 67% (59/88) and msp2 44% (39/88) were observed. K1 was the predominant msp1 allelic family observed in 33.9% (20/59) of the samples followed by RO33 and MAD20. Of the msp2 allelic family 3D7/IC1 showed higher frequency (21.5%) compared to FC27 (10.3%). A total of twenty-three alleles were detected; of which, eleven were from msp2 and twelve from msp2 genes. Fifty-nine percent of isolates had multiple genotypes and the overall mean multiplicity of infection was 1.8 (95% CI: 1.48-2.04). The heterozygosity index was 0.79 and 0.54for msp1 and msp2, respectively. There was no statically significant difference in the multiplicity of infection by either age or parasite density (P > 0.05). CONCLUSION: This genetic diversity study showed the presence of five allelic types in the study area, with dominance K1 in the msp1 family and 3D7/IC1 in the msp2 family. Multiple infections were observed in nearly 60% of the samples.

Malaria pattern observed in the highland fringe of Butajira, Southern Ethiopia: a ten-year retrospective analysis from parasitological and metrological data.

Background: Studying the magnitude of highland malaria is necessary to implement effective control measures in highland fringes of Ethiopia. Since repeated epidemics were reported in Butajira, this study hypothesized autochthonous transmission in the highland fringes of Butajira. Thus we aimed to determine the malaria occurrence and its association with meteorological variables in the highland fringe of Butajira, Southern Ethiopia from parasitological and metrological data. Methods: Retrospective monthly malaria case data was collected from monthly outpatient morbidity reports of the Butajira Health Center, for January 2000 to December 2009. Monthly total rainfall and average temperature (maximum and minimum), which was recorded in Butajira weather station, was obtained from National Meteorological Agency, for the same period. Spearman correlation coefficient was used to quantify the strength of linear relationships between meteorological variables and malaria cases. The effect of each independent variable on malaria cases was assessed using multiple linear regression. Results: During the study period, a fluctuating trend of malaria cases was observed with Plasmodium vivax (62.5%) dominancy. The highest occurrence of malaria was recorded in 2003, 2004, 2008 and 2009 and the least was recorded in 2000-2002. None of the meteorological variables was positively correlated with monthly malaria cases at zero months lag. However, minimum temperature was positively correlated with total malaria cases, P. vivax and P. falciparum with one month lag. Correlation analysis showed that all of the meteorological variables, except maximum temperature at one month lag, were not significant with total monthly malaria cases and each species of malaria (P-value >0.05) at zero and one month lag effect. Nevertheless, after adjusting for the effect of other variables the linear regression analysis indicated that cumulative monthly rainfall (Beta= -0.24; 95% CI: -0.47, -0.02) at zero months lag and maximum temperature (Beta= -12.13; 95% CI: -23.43, -0.82) at one month lag had a significant negative effect on the total malaria count. Conclusion: There was no significant association between malaria occurrences and meteorological variables between January 2000 and December 2009; therefore non-climatic factors together with climatic variables should be assessed to know the spread and intensity of malaria in the highland fringe of Butajira. This report also warrants the Ministry of Health to include highland areas in its current malaria controlling campaign so as to address those non-endemic foci of the country.

Malaria prevalence pattern observed in the highland fringe of Butajira, Southern Ethiopia: a longitudinal study from parasitological and entomological survey.

BACKGROUND: In Ethiopia, information regarding highland malaria transmission is scarce, and no report has been presented from Butajira highland so far whether the appearance of malaria in the area was due to endemicity or due to highland malaria transmission. Thus this study aimed to determine the presence and magnitude of malaria transmission in Butajira. METHODS: For parasitological survey, longitudinal study was conducted from October to December 2006. The entomological surveys were done from October to December 2006 and continued from April to May 2007. Both parasitological and entomological surveys were done using standard procedures. RESULTS: The parasitological result in all the survey months (October-December) showed an overall detection rate of 4.4% (48/1082) (CI 95%; 3.2-5.7%) malaria parasite. Among infected individuals, 32 (3.0%) of the infection was due to Plasmodium vivax and the rest 16 (1.5%) were due to Plasmodium falciparum. The highest prevalence 39(3.6%) of the parasite was observed in age groups of above 15 years old. Among the total tested, 25(2.3%) of males and 23(2.1%) of females had malaria infection. Among tested individuals, 38(5.3%) and 10 (2.7%) of infection was occurred in Misrak-Meskan (2100 m a.s.l) and Mirab-Meskan (2280 m a.s.l), respectively which was statistically significant (X2=3.72, P<0.05). Although the prevalence pattern of Plasmodium species declined from October to December, the trend was non-significant (X2 for trend=0.49, P>0.05). The entomological survey showed a collection of 602 larvae and 80 adult Anopheles. Anopheles christyi was the dominant species both in the first (45.3%) and in the second (35.4%) surveys; where as, Anopheles gambiae sensu lato comprised 4.7% and 14.6%, in the first and second surveys, respectively. Anopheles gambiae s.l comprises 55% of the adult collection, and both species were collected more from outdoors (57.5%). The number of An. christyi was higher in Mirab-Meskan (58. 3%) than Misrak-Meskan (41.7%) (P<0.05). CONCLUSION: Malaria parasite and its vectors were found to be common during transmission periods in the highland fringes of Butajira. Thus, health education about the risk of malaria and its control programme in the area must be given adequate attention to minimize potential epidemics. In addition, the current study should be complemented from sero-epidemiological, prospective longitudinal and retrospective studies along with metrological and ecological factors, and socio-demographic data before concluding in favour of highland malaria transmission in the area. In light of its abundance, which coincided with the malaria transmission seasons, the possible role of An. christyi as a secondary vector in the highlands must be further investigated by including blood meal sources detection.