World Health Organization and the US Centers for Disease Control and Prevention.

The 2014–16 Ebola Virus Disease (EVD) outbreak in West Africa highlighted the necessity for readily available, accurate and rapid diagnostics. The magnitude of the outbreak and the re-emergence of clusters of EVD cases following the declaration of interrupted transmission in Liberia, reinforced the need for sustained diagnostics to support surveillance and emergency preparedness. We describe implementation of the Xpert Ebola Assay, a rapid molecular diagnostic test run on the GeneXpert platform, at a mobile laboratory in Liberia and the subsequent impact on EVD outbreak response, case management and laboratory system strengthening. During the period of operation, site coordination, management and operational capacity was supported through a successful collaboration between Ministry of Health (MoH), World Health Organization (WHO) and international partners. A team of Liberian laboratory technicians were trained to conduct EVD diagnostics and the laboratory had capacity to test 64–100 blood specimens per day. Establishment of the laboratory significantly increased the daily testing capacity for EVD in Liberia, from 180 to 250 specimens at a time when the effectiveness of the surveillance system was threatened by insufficient diagnostic capacity. During the 18 months of operation, the laboratory tested a total of 9,063 blood specimens, including 21 EVD positives from six confirmed cases during two outbreaks. Following clearance of the significant backlog of untested EVD specimens in November 2015, a new cluster of EVD cases was detected at the laboratory. Collaboration between surveillance and laboratory coordination teams during this and a later outbreak in March 2016, facilitated timely and targeted response interventions. Specimens taken from cases during both outbreaks were analysed at the laboratory with results informing clinical management of patients and discharge decisions. The GeneXpert platform is easy to use, has relatively low running costs and can be integrated into other national diagnostic algorithms. The technology has on average a 2-hour sample-to-result time and allows for single specimen testing to overcome potential delays of batching. This model of a mobile laboratory equipped with Xpert Ebola test, staffed by local laboratory technicians, could serve to strengthen outbreak preparedness and response for future outbreaks of EVD in Liberia and the region.

Ebola virus is known to persist in semen of male survivors of Ebola virus disease (EVD). However, maximum duration of, or risk factors for, virus persistence are unknown. We report an EVD survivor with preexisting HIV infection, whose semen was positive for Ebola virus RNA 565 days after recovery from EVD.

The glycosylphosphatidylinositol-specific phospholipase C or VSG lipase is the enzyme responsible for the cleavage of the glycosylphosphatidylinositol anchor of the variant surface glycoprotein (VSG) and concommitant release of the surface coat in Trypanosoma brucei during osmotic shock or extracellular acidic stress. In Xenopus laevis oocytes the VSG lipase was expressed as a nonacylated and a thioacylated form. This thioacylation occurred within a cluster of three cysteine residues but was not essential for catalytic activity per se. These two forms were also detected in trypanosomes and appeared to be present at roughly equivalent amounts. A reversible shift to the acylated form occurred when cells were triggered to release the VSG by either nonlytic acid stress or osmotic lysis. A wild type VSG lipase or a gene mutated in the three codons for the acylated cysteines were reinserted in the genome of a trypanosome null mutant for this gene. A comparative analysis of these revertant trypanosomes indicated that thioacylation might be involved in regulating enzyme access to the VSG substrate.African trypanosomes such as Trypanosoma brucei are parasitic protozoans responsible for sleeping sickness in humans and related diseases in other mammals. These cells are covered by a predominant surface antigen known as the variant surface glycoprotein (VSG), 1 and antigenic variation of this protein allows these parasites to escape the humoral immune defenses of the mammalian host (for a recent review see Ref. 1). The VSG is attached to the plasma membrane through a glycosylphosphatidylinositol (GPI) anchor (2) but can be released from the cellular surface by cleavage of the GPI anchor during cellular lysis or exposure to nonlytic stress conditions (3, 4). Cleavage of the GPI anchor of the membrane form of VSG (mfVSG) generates a soluble form (sVSG) of the protein that displays a neo-epitope termed the cross-reacting determinant (CRD) that is dependent on the presence of an inositol-1,2-cyclic phosphate that remains associated with the residue of the anchor left attached to the released VSG (5). The enzyme responsible for this cleavage is a GPI-specific phospholipase C, termed VSG lipase (6 -8), that is encoded by a single copy gene that is only expressed in bloodstream forms of the parasite (9, 10). This lipase possesses several rather curious features that deserve further comment. First, VSG lipase behaves as an integral membrane protein during purification and subcellular fractionation (6 -8, 11), even though the primary sequence does not contain any obvious hydrophobic stretches to account for this physical property. Second, the apparent subcellular localization of the protein to the cytoplasmic face of small intracellular vesicles (12) presents a topological problem: how does the enzyme gain access to the GPI substrate of the VSG, which is thought to be present on the outer leaflet of the plasma membrane? Third, despite considerable effort the physiological role of the VSG lipase remains elusive (13). At present there ...

Prior to the Ebola virus disease outbreak in Liberia, the laboratory system was duplicative, fragmented and minimally coordinated. The National Reference Laboratory was conceptualised to address the existing challenges by promoting the implementation of effective and sustainable laboratory services in Liberia. However, in a resource-limited environment such as Liberia, progress regarding the rebuilding of the health system can be relatively slow, while efforts to sustain the transient gains remain a key challenge for the Ministry of Health. In this paper, we describe the pre-Ebola virus disease laboratory system in Liberia and its prevailing efforts to address future emerging infectious diseases, as well as current Infectious diseases, all of which are exacerbated by poverty. We conclude that laboratory and diagnostic services in Liberia have encountered numerous challenges regarding its efforts to strengthen the healthcare delivery system. These challenges include limited trained human resource capacity, inadequate infrastructure, and a lack of coordination. As with most countries in sub-Saharan Africa, when comparing urban and rural settings, diagnostic and clinical services are generally skewed toward urban health facilities and private, faith-based health facilities. We recommend that structured policy be directed at these challenges for national institutions to develop guidelines to improve, strengthen and sustain diagnostic and curative laboratory services to effectively address current infectious diseases and prepare for future emerging and re-emerging infectious diseases.