Extensive genetic diversity of severe fever with thrombocytopenia syndrome virus circulating in Hubei Province, China, 2018-2022.

Severe fever with thrombocytopenia syndrome virus (SFTSV), an etiological agent causing febrile human disease was identified as an emerging tick-borne bunyavirus. The clinical disease characteristics and case fatality rates of SFTSV may vary across distinct regions and among different variant genotypes. From 2018 to 2022, we surveyed and recruited 202 severe fever with thrombocytopenia syndrome (SFTS) patients in Hubei Province, a high-incidence area of the epidemic, and conducted timely and systematic research on the disease characteristics, SFTSV diversity, and the correlation between virus genome variation and clinical diseases. Our study identified at least 6 genotypes of SFTSV prevalent in Hubei Province based on the analysis of the S, M, and L genome sequences of 88 virus strains. Strikingly, the dominant genotype of SFTSV was found to change during the years, indicating a dynamic shift in viral genetic diversity in the region. Phylogenetic analysis revealed the genetic exchange of Hubei SFTSV strains was relatively frequent, including 3 reassortment strains and 8 recombination strains. Despite the limited sample size, SFTSV C1 genotype may be associated with higher mortality compared to the other four genotypes, and the serum amyloid A (SAA) level, an inflammatory biomarker, was significantly elevated in these patients. Overall, our data summarize the disease characteristics of SFTSV in Hubei Province, highlight the profound changes in viral genetic diversity, and indicate the need for in-depth monitoring and exploration of the relationship between viral mutations and disease severity.

Fentanyl enhances HIV infection in vitro.

Acquired immunodeficiency syndrome (AIDS) caused by Human immunodeficiency virus type 1 (HIV-1) has a high tendency among illicit drug abusers. Recently, it is reported that abuse of fentanyl, a potent synthetic µ receptor-stimulating opioid, is an independent risk factor for HIV-1 infection. However, the mechanism of action in augmenting HIV-1 infection still remains elusive. In this study, we found that fentanyl enhanced infection of HIV-1 in MT2 cells, primary macrophages and Jurkat C11 cells. Fentanyl up-regulated CXCR4 and CCR5 receptor expression, which facilitated the entry of virion into host cells. In addition, it down-regulated interferon-ß (IFN-ß) and interferon-stimulated genes (APOBEC3F, APOBEC3G and MxB) expression in MT2 cells. Our findings identify an essential role of fentanyl in the positive regulation of HIV-1 infection via the upregulation of co-receptors (CXCR4/CCR5) and downregulation of IFN-ß and ISGs, and it may have an important role in HIV-1 immunopathogenesis.

A shift away from mutualism under food-deprived conditions in an anemone-dinoflagellate association.

The mutualistic symbiosis between anthozoans and intra-gastrodermal dinoflagellates of the family Symbiodiniaceae is the functional basis of all coral reef ecosystems, with the latter providing up to 95% of their fixed photosynthate to their hosts in exchange for nutrients. However, recent studies of sponges, jellyfish, and anemones have revealed the potential for this mutualistic relationship to shift to parasitism under stressful conditions. Over a period of eight weeks, we compared the physiological conditions of both inoculated and aposymbiotic anemones (Exaiptasia pallida) that were either fed or starved. By the sixth week, both fed groups of anemones were significantly larger than their starved counterparts. Moreover, inoculated and starved anemones tended to disintegrate into "tissue balls" within eight weeks, and 25% of the samples died; in contrast, starved aposymbiotic anemones required six months to form tissue balls, and no anemones from this group died. Our results show that the dinoflagellates within inoculated anemones may have posed a fatal metabolic burden on their hosts during starvation; this may be because of the need to prioritize their own metabolism and nourishment at the expense of their hosts. Collectively, our study reveals the potential of this dynamic symbiotic association to shift away from mutualism during food-deprived conditions.