Towards the complete eradication of mother-to-child HIV/HBV coinfection at Saint Camille Medical Centre in Burkina Faso, Africa

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Both Lewis and Secretor Status Mediate Susceptibility to Rotavirus Infections in a Rotavirus Genotype–Dependent Manner

Background. The live oral rotavirus (RV) vaccines have shown a reduced efficacy in Africa. Recent in vitro studies have shown binding of the RV surface protein (VP4) to histo–blood group antigens (HBGAs) in an RV genotype–dependent manner, suggesting them to be putative receptors for RV. The diversity of HBGA phenotypes in different ethnic populations, combined with prevalence/absence of specific RV genotypes, led us to hypothesize whether the genetic variations in HBGAs in a population limit susceptibility to certain RV genotypes, plausibly leading to reduced vaccine efficacy

Host Genetic Factors Affect Susceptibility to Norovirus Infections in Burkina Faso

Norovirus (NoV) constitutes the second most common viral pathogen causing pediatric diarrhea after rotavirus. In Africa, diarrhea is a major health problem in children, and yet few studies have been performed regarding NoV. The association of histo-blood group antigens (HBGA) and susceptibility to NoV infection is well established in Caucasian populations with non-secretors being resistant to many common NoV strains. No study regarding HBGA and NoV susceptibility has yet been performed in Africa. We collected 309 stool and 208 saliva samples from diarrheal children in Ouagadougou, Burkina Faso; May 2009 to March 2010. NoV was detected using real-time PCR, and genotyped by sequencing. Saliva samples were ABO, Lewis and secretor phenotyped using in house ELISA assays. NoV was detected in 12% (n = 37) of the samples. The genotype diversity was unusually large; overall the 37 positive samples belonged to 14 genotypes. Only children <2 years of age were NoV positive and the GII.4 NoVs were more frequent in the late dry season (Jan-May). NoV infections were observed less in children with the secretor-negative phenotype or blood group A (OR 0.18; p = 0.012 and OR 0.31; p = 0.054; respectively), with two non-secretors infected with genotypes GII.7 and GII.4 respectively. Lewis-negative (Lea−b−) children, representing 32% of the study population, were susceptible to GII, but were not infected with any NoV GI. GII.4 strains preferentially infected children with blood group B whereas secretor-positive children with blood group O were infected with the largest variety of genotypes. This is the first study identifying host genetic factors associated with susceptibility to NoV in an African population, and suggests that while the non-secretor phenotype provides protection; the Lewis b antigen is not necessary for GII infection

Promotion of dialogue speech for children aged 5 – 7 years while solving problem situations at pre-school

Norovirus (NoV) constitutes the second most common viral pathogen causing pediatric diarrhea after rotavirus. In Africa, diarrhea is a major health problem in children, and yet few studies have been performed regarding NoV. The association of histo-blood group antigens (HBGA) and susceptibility to NoV infection is well established in Caucasian populations with non-secretors being resistant to many common NoV strains. No study regarding HBGA and NoV susceptibility has yet been performed in Africa. We collected 309 stool and 208 saliva samples from diarrheal children in Ouagadougou, Burkina Faso; May 2009 to March 2010. NoV was detected using real-time PCR, and genotyped by sequencing. Saliva samples were ABO, Lewis and secretor phenotyped using in house ELISA assays. NoV was detected in 12% (n = 37) of the samples. The genotype diversity was unusually large; overall the 37 positive samples belonged to 14 genotypes. Only children <2 years of age were NoV positive and the GII.4 NoVs were more frequent in the late dry season (Jan-May). NoV infections were observed less in children with the secretor-negative phenotype or blood group A (OR 0.18; p = 0.012 and OR 0.31; p = 0.054; respectively), with two non-secretors infected with genotypes GII.7 and GII.4 respectively. Lewis-negative (Lea−b−) children, representing 32% of the study population, were susceptible to GII, but were not infected with any NoV GI. GII.4 strains preferentially infected children with blood group B whereas secretor-positive children with blood group O were infected with the largest variety of genotypes. This is the first study identifying host genetic factors associated with susceptibility to NoV in an African population, and suggests that while the non-secretor phenotype provides protection; the Lewis b antigen is not necessary for GII infection

Temporal distribution of norovirus genogroups/genotypes in Ouagadougou, Burkina Faso from end of May 2009 to March 2010; each tick representing 3 weeks.

<p>Rainy season (June-September), cold dry season (December-February).</p

Host genetic factors and association to susceptibility to NoV infections in Burkina Faso.

1<p>21% and 79% of Lewis-negative children were non-secretors and secretors; respectively.</p>2<p>Including 1 non-secretor and 11 secretors.</p>3<p>Only determined for secretor-positive individuals.</p>4<p>Saliva was lacking for one NoV-positive child.</p>5<p>Chi square test with two-tailed significance.</p>6<p>Fisher exact test with two-tailed significance.</p

Relationship between genogroups, genotypes, and HBGAs in NoV infected children in Burkina Faso.

1<p>Only determined for secretor-positive individuals.</p>2<p>Belonging to a yet undefined genotype (86.1% nt identity to most similar reference sequence).</p>3<p>Not genotyped.</p>4<p>Saliva was lacking for one NoV-positive child of genogroup II.</p

Differences between NoV genogroups and genotypes regarding susceptibility patterns (%).

1<p>Blood groups were only determined for secretor-positive individuals.</p>2<p>Fisher exact test with two-tailed significance.</p

Clinical features of NoV-infected children with and without concomitant infections.

1<p>Dehydration status was not obtained for 1 of the NoV-positive (GII.4) children.</p>2<p>Two NoV positive could not be genotyped and were excluded from the analysis.</p>3<p>Enteropathogens screened: Rotavirus, <i>Shigella spp</i>, <i>Salmonella spp,</i> enteropathogenic <i>Escherichia coli</i>, <i>Giardia lamblia, Trichomonas intestinalis, Entamoeba histolytica/dispar.</i> Includes 4 GII.4 genotypes.</p