Dengue virus serotypes and related factors in children with dengue hemorrhagic fever in Southern Vietnam.

INTRODUCTION: After the Coronavirus Disease 2019 pandemic, a high number of cases and severe dengue in children were reported in some provinces in the south of Vietnam. This study aimed to determine the distribution of dengue virus serotypes and their correlation with demographic factors, disease severity, clinical manifestations, and laboratory findings. METHODOLOGY: This study employed a cross-sectional design. Ninety-six dengue-infected children admitted to Can Tho Children's Hospital between October 2022 and March 2023 were included. Confirmation of dengue infection was achieved through the real-time polymerase chain reaction (RT-PCR). RESULTS: Among the identified serotypes, DENV-2 accounted for the highest proportion (71.87%), followed by DENV-1 (23.96%), and DENV-4 (4.17%). DENV-3 was not detected. No significant demographic, disease severity, or laboratory differences were observed among the identified dengue serotypes. However, DENV-2 was associated with a higher occurrence of mucous membrane hemorrhages and gastrointestinal bleeding compared to other serotypes. CONCLUSIONS: Although DENV-2 was the most prevalent serotype responsible for dengue in children in southern Vietnam, it did not lead to more severe cases compared to other serotypes. This finding is crucial for evaluating the illness's prognosis.

Effects of phytoplankton cell size and chloride concentration on the bioaccumulation of methylmercury in marine phytoplankton.

In the current study, the effects of phytoplankton cell size and methylmercury (MeHg) speciation on the bioaccumulation of MeHg by marine phytoplankton were investigated. Volume concentration factors (VCFs) of MeHg were determined in relation to the surface area to volume ratio of the cells for four species of diatom and a cyanobacteria species cultured in unenriched seawater. The VCFs of MeHg, ranging from 7.3 × 10(4) to 1.6 × 10(6) , increased linearly as the cell surface area-to-volume ratio increased. It suggests that pico- and nano-dominated phytoplankton communities may lead to larger MeHg accumulation than the one dominated by microphytoplankton. MeHg VCFs increased with increasing chloride concentration from 0.47 to 470 mM, indicating that MeHg bioaccumulation is enhanced under conditions that facilitate membrane permeability by the formation of neutral MeHgCl species. Overall results suggest that the size distributions of the planktonic community as well as the seawater chemistry affect MeHg bioaccumulation by marine phytoplankton.