Distribution of HLA-DQ risk genotypes for celiac disease in Ethiopian children.

Most patients with celiac disease are positive for either HLA-DQA1*05:01-DQB1*02 (DQ2.5) or DQA1*03:01-DQB1*03:02 (DQ8). Remaining few patients are usually DQA1*02:01-DQB1*02 (DQ2.2) carriers. Screenings of populations with high frequencies of these HLA-DQA1-DQB1 haplotypes report a 1% to 3% celiac disease prevalence. The aim was to determine the prevalence of HLA-DQ risk haplotypes for celiac disease in Ethiopian children. Dried blood spots collected from 1193 children from the Oromia regional state of Ethiopia were genotyped for HLA-DQA1 and DQB1 genotyping using an asymmetric polymerase chain reaction (PCR) and a subsequent hybridization of allele-specific probes. As references, 2000 previously HLA-genotyped children randomly selected from the general population in Sweden were included. DQ2.2 was the most common haplotype and found in 15.3% of Ethiopian children, which was higher compared with 6.7% of Swedish references (P < .0001). Opposed to this finding, DQ2.5 and DQ8 occurred in 9.7% and 6.8% of Ethiopian children, which were less frequent compared with 12.8% and 13.1% of Swedish references, respectively (P < .0001). The DQ2.5-trans genotype encoded by DQA1*05-DQB1*03:01 in combination with DQ2.2 occurred in 3.6% of Ethiopian children, which was higher compared with 1.3% of Swedish references (P < .0001). However, when children with moderate high to very high-risk HLA genotypes were grouped together, there was no difference between Ethiopian children and Swedish references (27.4% vs 29.0%) (P = .3504). The frequency of HLA risk haplotypes for celiac disease is very similar in Ethiopian and Swedish children. This finding of importance will be useful in future screening of children for celiac disease in Ethiopia.

Determination of the human blood index of some anopheline mosquitos by using ELISA.

To determine the human blood index, 1253 anopheline mosquitos collected from Arbaminch, Awassa, Metahara and Ziway were tested by the blood meal ELISA, based on anti-human IgG. Higher positivity for human blood were observed in anopheline mosquitos collected from mixed dwellings (range, 26-92%) while those from animal shelters had the lowest positivity (range, 9-48%). The human blood index for A. arabiensis, a principal malaria vector in most parts of the country, from mixed dwelling collections was 88% while it was 43% for those collected from animal shelters. For A. pharoensis, it was 84% and 9%, and for A. coustani, it was 26% and 15% for the respective sites of collection. The human blood index of A. marshalli was 40%; for A. demeilloni, it was 36%; and for A. christyi, 91% for collections from mixed dwellings, while 35% for A. tenebrosus was determined for those collected from animal shelters. Out of the 15 A. funestus and the 11 A. longipalpis tested, 13 and 8 were positive for human blood, respectively. As the feeding and resting preference of the mosquitos varied, malaria control measures must be based on integrated measures in order to reduce man-mosquito contact.

Some aspects of malaria prevalence; vector infectivity and DDT resistance studies in Gambella region; South Western Ethiopia

Prevalence of plasmodium falciparum and plasmodium vivax in the human population; infectivity and DDT resistance of Anopheles mosquitoes were studied on samples collected during the peak malaria season of 1990 from Gambella; South West Ethiopia. Mosquito vectors collected were assorted into species and their infectivity with malaria parasites was determined by the enzyme-linked immunosorbent assay (ELISA). In the human population out of a total of 821 individuals examined from nine villages; 4.1 percent (34) were found to be positive for malaria parasites. Of the 34 positive individuals 5.9 percent (2) were positive for plasmodium vivax and 94.1 percent (32) for plasmodium falciparum. Although relatively high positivity rates for malaria were observed in 1-4 and 5-14 age groups; the difference in rates of positivity was not statistically significant for the whole population (p=0.5077). However; a significant difference in parasite prevalence was detected between the nine localities. Compared to that of 1989; the overall malaria prevalence rate in the human population significantly decreased in 1990. Insecticide susceptibilty studies revealed the presence of DDT resistant Anopheles gambiae s.l. mosquito in Itang. Furthermore; a strong evidence would suspect the vectorial status of A. pharoensis was obtained by detecting salivary gland sporozoite antigens of P. vivax in the head region of two mosquitos. Sporozoite rate of 0.76 percent (P. falciparum) for A. gambiae s.l. and 0.47 percent (P. vivax) for A. pharoensis were determined