Deposition of aggregated Aβ peptide in the brain is one of the major hallmarks of Alzheimer's disease. Using a combination of two structurally different, but related, hypersensitive fluorescent amyloid markers, LCOs, reporting on separate ultrastructural elements, we show that conformational rearrangement occurs within Aβ plaques of transgenic mouse models as the animals age. This important mechanistic insight should aid the design and evaluation of experiments currently using plaque load as readout.

We report on an Ebola virus disease (EVD) survivor who showed Ebola virus in seminal fluid 531 days after onset of disease. The persisting virus was sexually transmitted in February 2016, about 470 days after onset of symptoms, and caused a new cluster of EVD in Guinea and Liberia.

The family Bunyaviridae is the most diversified family of RNA viruses. We describe a novel prototypic bunyavirus, tentatively named Gouléako virus, isolated from various mosquito species trapped in Côte d'Ivoire. The S segment comprised 1,087 nucleotides (nt), the M segment 3,188 nt, and the L segment 6,358 nt, constituting the shortest bunyavirus genome known so far. The virus had shorter genome termini than phleboviruses and showed no evidence of encoded NSs and NSm proteins. An uncharacterized 105-amino-acid (aa) putative open reading frame (ORF) was detected in the S segment. Genetic equidistance to other bunyaviruses (74 to 88% aa identity) and absence of serological cross-reactivity with phleboviruses suggested a proposed novel Bunyaviridae genus.

Prokop et al. demonstrate that conditional ablation of resident microglia in a mouse model of Alzheimer’s disease (AD) results in no significant change in amyloid-β burden, despite nearly complete replacement with peripheral myeloid cells. The findings suggest that additional triggers appear to be required to exploit the full potential of myeloid cell–based therapies for AD.

Investment in SARS-CoV-2 sequencing in Africa over the past year has led to a major increase in the number of sequences generated, now exceeding 100,000 genomes, used to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence domestically, and highlight that local sequencing enables faster turnaround time and more regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and shed light on the distinct dispersal dynamics of Variants of Concern, particularly Alpha, Beta, Delta, and Omicron, on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve, while the continent faces many emerging and re-emerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century.