Detection of Crimean-Congo haemorrhagic fever virus in Hyalomma marginatum ticks, southern France, May 2022 and April 2023

Crimean-Congo haemorrhagic fever (CCHF), a potentially severe zoonotic viral disease causing fever and haemorrhagic manifestations in humans. As the Crimean-Congo haemorrhagic fever virus (CCHFV) has been detected in ticks in Spain and antibodies against the virus in ruminant sera in Corsica, it was necessary to know more about the situation in France. In 2022-2023, CCHFV was detected in 155 ticks collected from horses and cattle in southern France.

Characterization and analytical validation of a new antigenic rapid diagnostic test for Ebola virus disease detection

Hemorrhagic fever outbreaks are difficult to diagnose and control in part because of a lack of low-cost and easily accessible diagnostic structures in countries where etiologic agents are present. Furthermore, initial clinical symptoms are common and shared with other endemic diseases such as malaria or typhoid fever. Current molecular diagnostic methods such as polymerase chain reaction require trained personnel and laboratory infrastructure, hindering diagnostics at the point of need, particularly in outbreak settings. Therefore, rapid diagnostic tests such as lateral flow can be broadly deployed and are typically well-suited to rapidly diagnose hemorrhagic fever viruses, such as Ebola virus. Early detection and control of Ebola outbreaks require simple, easy-to-use assays that can detect very low amount of virus in blood. Here, we developed and characterized an immunoassay test based on immunochromatography coupled to silver amplification technology to detect the secreted glycoprotein of EBOV. The glycoprotein is among the first viral proteins to be detected in blood. This strategy aims at identifying infected patients early following onset of symptoms by detecting low amount of sGP protein in blood samples. The limit of detection achieved by this sGP-targeted kit is 2.2 x 10⁴ genome copies/ml in plasma as assayed in a monkey analytical cohort. Clinical performance evaluation showed a specificity of 100% and a sensitivity of 85.7% when evaluated with plasma samples from healthy controls and patients infected with Zaire Ebola virus from Macenta, Guinea. This rapid and accurate diagnostic test could therefore be used in endemic countries for early detection of infected individuals in point of care settings. Moreover, it could also support efficient clinical triage in hospitals or clinical centers and thus reducing transmission rates to prevent and better manage future severe outbreaks.

Ebola virus disease is a severe disease caused by Ebola virus, a member of the filovirus family, which occurs in humans and other primates. Ebola is believed to be zoonotic, however the natural reservoir is unknown. Overlapping symptoms with other endemic diseases, such as malaria and cholera, make accurate diagnostic challenging. Outbreaks of Ebola have been widespread as the consequence of the absence of available rapid, sensitive, specific, robust, and affordable licensed diagnostic test in remote areas, where outbreaks usually start. Here we have established and validated a rapid diagnostic test, which is fast, sensitive, specific, efficient, affordable, and user-friendly. Its analytical characteristics make it suitable for clinical management during Ebola virus outbreaks in remote areas. Of interest, this rapid diagnostic test detects the presence of an early viral antigen, the secreted glycoprotein, found in blood of patients shortly after infection, suggesting that it could be used to identify infected patients shortly after onset of symptoms.

Correction: Experimental Treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial): A Historically Controlled, Single-Arm Proof-of-Concept Trial in Guinea

[This corrects the article DOI: 10.1371/journal.pmed.1001967.].

[Enteroviruses receptors and cell entry]

Human enteroviruses, which belong to the family of Picornaviridae, are common infectious viral agents transmitted by fecal-oral or airway routes. These positive RNA viruses possess a high genetic diversity and variability. They can evolve through genetic mutations or recombination mechanisms that are associated to the emergence of new potential epidemic serotypes. Human enteroviruses use different cellular receptors: receptors and co-receptors that are directly related to the tropism and the epidemiologic characteristics of some enterovirus serotypes. The receptors onto the cell-surface settle within a capsid depression, called canyon, initiating the process of viral uncoating. For some enteroviruses, a co-receptor molecule allows the crossing of cell topological barriers that is required to initiate the target cell infection. After the attachment phase, enteroviruses use the endocellar signaling pathways to support and optimize their entry into target-cells via endocytic pathways. The clathrin coated pits and the caveolae are both major ways of enterovirus entry in the cell even if "new" endocytic pathways regulated by enzymes of theADP ribosylation factors family and of the Rho family small GTPases have been recently described. The viral genetic diversity allows the human enteroviruses to simultaneously or alternatively use several distinct endocytic pathways in accordance to the infected cell lines, and allows a rapid and efficient adaptation to cellular microenvironments and to multiple immune selection pressures developed during the pathophysiological course of human infection. In conclusion, entry mechanisms used by human enteroviruses to infect target cells are various but they are closely dependent on the cellular functions that will be driven towards viral benefits. In the present time, the attachment and entry phases of the human enteroviruses into the target cell represent major viral events that may be targeted for the development of further new antiviral strategies.