Dataset Information

Prevalence and genetic diversity of human astroviruses in Mexican children with symptomatic and asymptomatic infections.

ABSTRACT: The prevalence and type diversity of human astroviruses (HAstV) in children with symptomatic and asymptomatic infections were determined in five localities of Mexico. HAstV were detected in 4.6 (24 of 522) and 2.6% (11 of 428) of children with and without diarrhea, respectively. Genotyping of the detected strains showed that at least seven (types 1 to 4 and 6 to 8) of the eight known HAstV types circulated in Mexico between October 1994 and March 1995. HAstV types 1 and 3 were the most prevalent in children with diarrhea, although they were not found in all localities studied. HAstV type 8 was found in Mexico City, Monterrey, and Mérida; in the last it was as prevalent (40%) as type 1 viruses, indicating that this astrovirus type is more common than previously recognized. A correlation between the HAstV infecting type and the presence or absence of diarrheic symptoms was not observed. Enteric adenoviruses were also studied, and they were found to be present in 2.3 (12 of 522) and 1.4% (6 of 428) of symptomatic and asymptomatic children, respectively.

SUBMITTER: Mendez-Toss M

PROVIDER: S-EPMC321733 | biostudies-literature | 2004 Jan

REPOSITORIES: biostudies-literature

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Prevalence and genetic diversity of human astroviruses in Mexican children with symptomatic and asymptomatic infections.

Méndez-Toss Martha M Griffin Dixie D DD Calva Juan J Contreras Juan F JF Puerto Fernando I FI Mota Felipe F Guiscafré Héctor H Cedillo Roberto R Muñoz Onofre O Herrera Ismael I López Susana S Arias Carlos F CF

Journal of clinical microbiology 20040101 1

The prevalence and type diversity of human astroviruses (HAstV) in children with symptomatic and asymptomatic infections were determined in five localities of Mexico. HAstV were detected in 4.6 (24 of 522) and 2.6% (11 of 428) of children with and without diarrhea, respectively. Genotyping of the detected strains showed that at least seven (types 1 to 4 and 6 to 8) of the eight known HAstV types circulated in Mexico between October 1994 and March 1995. HAstV types 1 and 3 were the most prevalent ...[more]

PMID: 14715746

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Project description:BACKGROUND:The immune mechanisms that determine whether a Plasmodium falciparum infection would be symptomatic or asymptomatic are not fully understood. Several studies have been carried out to characterize the associations between disease outcomes and leucocyte numbers. However, the majority of these studies have been conducted in adults with acute uncomplicated malaria, despite children being the most vulnerable group. METHODS:Peripheral blood leucocyte subpopulations were characterized in children with acute uncomplicated (symptomatic; n?=?25) or asymptomatic (n?=?67) P. falciparum malaria, as well as malaria-free (uninfected) children (n?=?16) from Obom, a sub-district of Accra, Ghana. Leucocyte subpopulations were enumerated by flow cytometry and correlated with two measures of parasite load: (a) plasma levels of P. falciparum histidine-rich protein 2 (PfHRP2) as a proxy for parasite biomass and (b) peripheral blood parasite densities determined by microscopy. RESULTS:In children with symptomatic P. falciparum infections, the proportions and absolute cell counts of total (CD3?+) T cells, CD4?+?T cells, CD8?+?T cells, CD19?+?B cells and CD11c?+?dendritic cells (DCs) were significantly lower as compared to asymptomatic P. falciparum-infected and uninfected children. Notably, CD15?+?neutrophil proportions and cell counts were significantly increased in symptomatic children. There was no significant difference in the proportions and absolute counts of CD14?+?monocytes amongst the three study groups. As expected, measures of parasite load were significantly higher in symptomatic cases. Remarkably, PfHRP2 levels and parasite densities negatively correlated with both the proportions and absolute numbers of peripheral leucocyte subsets: CD3?+?T, CD4?+?T, CD8?+?T, CD19?+?B, CD56?+?NK, ???+?T and CD11c?+?cells. In contrast, both PfHRP2 levels and parasite densities positively correlated with the proportions and absolute numbers of CD15?+?cells. CONCLUSIONS:Symptomatic P. falciparum infection is correlated with an increase in the levels of peripheral blood neutrophils, indicating a role for this cell type in disease pathogenesis. Parasite load is a key determinant of peripheral cell numbers during malaria infections.

Project description:BackgroundMore than a decade after the outbreak of human coronaviruses (HCoVs) SARS in Guangdong province and Hong Kong SAR of China in 2002, there is still no reoccurrence, but the evolution and recombination of the coronaviruses in this region are still unknown. Therefore, surveillance on the prevalence and the virus variation of HCoVs circulation in this region is conducted.MethodsA total of 3298 nasopharyngeal swabs samples were collected from cross-border children (<6 years, crossing border between Southern China and Hong Kong SAR) showing symptoms of respiratory tract infection, such as fever (body temperature > 37.5 °C), from 2014 May to 2015 Dec. Viral nucleic acids were analyzed and sequenced to study the prevalence and genetic diversity of the four human coronaviruses. The statistical significance of the data was evaluated with Fisher chi-square test.Results78 (2.37%; 95%CI 1.8-2.8%) out of 3298 nasopharyngeal swabs specimens were found to be positive for OC43 (36;1.09%), HKU1 (34; 1.03%), NL63 (6; 0.18%) and 229E (2;0.01%). None of SARS or MERS was detected. The HCoVs predominant circulating season was in transition of winter to spring, especially January and February and NL63 detected only in summer and fall. Complex population with an abundant genetic diversity of coronaviruses was circulating and they shared homology with the published strains (99-100%). Besides, phylogenetic evolutionary analysis indicated that OC43 coronaviruses were clustered into three clades (B,D,E), HKU1 clustered into two clades(A,B) and NL63 clustered into two clades(A,B). Moreover, several novel mutations including nucleotides substitution and the insertion of spike of the glycoprotein on the viral surface were discovered.ConclusionsThe detection rate and epidemic trend of coronaviruses were stable and no obvious fluctuations were found. The detected coronaviruses shared a conserved gene sequences in S and RdRp. However, mutants of the epidemic strains were detected, suggesting continuous monitoring of the human coronaviruses is in need among cross-border children, who are more likely to get infected and transmit the viruses across the border easily, in addition to the general public.

Dataset Information

Prevalence and genetic diversity of human astroviruses in Mexican children with symptomatic and asymptomatic infections.

Publications

Prevalence and genetic diversity of human astroviruses in Mexican children with symptomatic and asymptomatic infections.

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