Multiple virus infections on Heterobasidion sp.

Heterobasidion viruses have previously been shown to affect each other’s transmission and phenotypic effects on their hosts in a complex way. In this work, Heterobasidion parviporum strains hosting five coinfecting viruses simultaneously were constructed and used as donors in transmission experiments. They showed that viruses move more frequently between the mycelia of the same species than between the mycelia of H. parviporum and Heterobasidion annosum. One of the strains was used to show that coinfection of five viruses is relatively unstable in a natural environment and analyses of the growth rate and competitive ability of Heterobasidion strains hosting various virus combinations revealed that viral effects are not additive. The results also supported the view that the transmission of the promising virocontrol agent HetPV13-an1 may be enhanced by coinfecting viruses in the donor mycelium. However, its detrimental effects may be blocked by the presence of other viruses in the same mycelium.RepositoriesGenBank accession number MN058080.     

Differential gene expression changes in children with severe dengue virus infections

Background

The host response to dengue virus infection is characterized by the production of numerous cytokines, but the overall picture appears to be complex. It has been suggested that a balance may be involved between protective and pathologic immune responses. This study aimed to define differential immune responses in association with clinical outcomes by gene expression profiling of a selected panel of inflammatory genes in whole blood samples from children with severe dengue infections.

Methodology/Principal Findings

Whole blood mRNA from 56 Indonesian children with severe dengue virus infections was analyzed during early admission and at day −1, 0, 1, and 5–8 after defervescence. Levels were related to baseline levels collected at a 1-month follow-up visit. Processing of mRNA was performed in a single reaction by multiplex ligation-dependent probe amplification, measuring mRNA levels from genes encoding 36 inflammatory proteins and 14 Toll-like receptor (TLR)-associated molecules. The inflammatory gene profiles showed up-regulation during infection of eight genes, including IFNG and IL12A, which indicated an antiviral response. On the contrary, genes associated with the nuclear factor (NF)-κB pathway were down-regulated, including NFKB1, NFKB2, TNFR1, IL1B, IL8, and TNFA. Many of these NF-κB pathway–related genes, but not IFNG or IL12A, correlated with adverse clinical events such as development of pleural effusion and hemorrhagic manifestations. The TLR profile showed that TLRs were differentially activated during severe dengue infections: increased expression of TLR7 and TLR4R3 was found together with a decreased expression of TLR1, TLR2, TLR4R4, and TLR4 co-factor CD14.

Conclusions/Significance

These data show that different immunological pathways are differently expressed and associated with different clinical outcomes in children with severe dengue infections.     

Respiratory syncytial virus infections in children in Montreal: a retrospective study

Seventy-seven hospitalized children from whom respiratory syncytial virus was subsequently isolated were studied in retrospect. This demonstrated the association of host invasion by this agent with an acute respiratory disease requiring hospitalization for approximately one week.Boys considerably outnumbered girls, the average age was 7.5 months, and in 56% the admission diagnosis was “bronchiolitis”. Cough and difficulty in breathing were the most common presenting complaints and “pneumonia” the most common radiological diagnosis. Nearly half the patients also harboured accepted disease-causing bacterial pathogens. All the patients recovered and have remained well.The appearance of the virus in Montreal was seasonal, beginning in late autumn and terminating in early spring.     

Atypical measles infections in leukaemic children on immunosuppressive treatment.

One case of giant-cell pneumonia and two of encephalopathy, all due to measles infection in children in leukaemic remission on immunosuppressive treatment, were seen recently. The clinical syndromes were variable and atypical and the antibody responses unpredictable. Conventional doses of pooled immunoglobulin failed to protect the two children to whom it was given. Degeneration rather than inflammation seems to characterise the encephalopathy in immunosuppressed children infected with measles virus.