Diagnosis Of Viral Hemorrhagic Fevers Research Articles

Report of a fatal case of Lassa fever in Parakou in 2018: clinical, therapeutic and diagnostic aspects

BackgroundLassa fever is one of the most lethal neglected tropical diseases in West Africa. It is a serious public health problem in this region of Africa where it is endemic in several countries. However, it remains a very little known disease by healthcare workers. The lack of specificity of its clinical manifestations makes its diagnosis difficult even in an epidemic context.Case presentationWe report here a confirmed case of Lassa fever whose diagnosis could not be suspected until 11 days after the symptomatology began. This case was recognized as a suspected case of Lassa fever in the Internal Medicine Department of the Regional and Teaching Hospital of Borgou due to the persistence of the fever and the worsening of the patient’s clinical condition despite triple antibiotic therapy in general and especially due to the appearance of hemorrhages. Confirmation of the presence of Lassa fever virus by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) assay on blood sample was obtained after his death despite late initiation of Ribavirin treatment.ConclusionThis case challenges Benin’s health authorities on the need to facilitate access to diagnosis of viral hemorrhagic fevers and to train caregivers at all levels of the health system for better management of these diseases.

Central Nervous System Disease Associated with Major Viral Haemorrhagic Fever Viruses of Public Health Importance: Challenges in Patient Diagnosis, Evaluation, and Management in Resource-Limited Settings

Viral haemorrhagic fever (VHF) viruses cause infectious diseases that are of public health importance. Billions of people from all over the world are at risk of exposure to infection from these viruses with epidemics or outbreaks occurring in both endemic and non-endemic areas. The VHF viruses are largely neglected but are re-emerging as real threats to global health. While the more dramatic clinical presentations (such as bleeding and vascular collapse) are well known, the contribution of features that involve the central nervous system (CNS) to mortality and morbidity are not fully recognised. The diagnosis of VHF in febrile patients with CNS-related features, but who do not present with characteristic bleeding, may be missed or delayed because of a low index of suspicion. The proper evaluation of such patients with CNS disease is hampered by the dearth of neurologists and investigational tools, and weak health systems in resource-limited settings where most of the VHF viruses are endemic. Addressing these constraints would require investment in capacity building and infrastructural development in the affected countries.

Diagnosis of Viral Hemorrhagic Fevers in Travelers Returning From West Africa

To the Editor‐in‐Chief A recent report documented the occurrence of dengue virus type‐3 infection in a traveler returning from Benin. In their discussion, the authors mentioned the importance of the diagnosis of dengue fever in the presence of other viruses like Lassa fever and yellow fever viruses endemic in the same areas. The authors did not offer any suggestions how to clinically differentiate infections …

Dengue and Other Viral Hemorrhagic Fevers in India

The important viral hemorrhagic fevers (VHF) in India spread by an arthropod vectors are Dengue fever/Dengue haemorrhagic fever and Kyasanur forest disease. Another VHF is caused by Hanta virus infection and for this there is no known vector. The diagnosis of VHF is based on typical clinical presentation and thereafter confirmed by detection of either virus or viral RNA or by demonstration of a rise of antibody titres against it. Treatment is by and large symptomatic as there are no specific drugs available against the viruses. Dengue fever has acquired epidemic magnitude in certain parts of India and has about 10% mortality. Research is going on for the development of effective vaccines against Dengue fever. The principles of primary prevention of vector borne diseases is through vector control measures, elimination of breeding sites in and around human dwellings and personal protection against vector bite.

Fluorescent microbeads-based multiplex detection of IgM antibodies to pathogens caused viral hemorrhagic fever

To develop and evaluate a multiplex detection of IgM antibodies to pathogens caused viral hemorrhagic fever. The nucleocapsid proteins (NP) of HTN, SEO, Puu MBV, Lassa, RFV and HPS viruses expressed in prokaryotic cells and purified were coupled to 7 different xMAP fluorescent microbeads. The assay was evaluated and optimized when screened against a panel of reference sera collected from HFRS patients, and compared to commonly used MacELISA Kits. For detection of anti-NP antibodies, the sensitivity and specificity of the assay were comparable to a commonly used MacELISA kit, but it could detect different antigen specific antibodies in one reaction simultaneously. A robust, rapid and multiplex assay based on NPs could be developed via Luminex xMAP platform for laboratory diagnosis of viral hemorrhagic fever and seroepidemiological investigation.

Laboratory safe detection of nucleocapsid protein of Rift Valley fever virus in human and animal specimens by a sandwich ELISA

A safe laboratory procedure, based on a sandwich ELISA (sAg-ELISA), was developed and evaluated for the detection of nucleocapsid protein (NP) of Rift Valley fever virus (RVFV) in specimens inactivated at 56 °C for 1 h in the presence of 0.5% Tween-20 (v/v) before testing. Polyclonal capture and detection immune sera were generated respectively in sheep and rabbits immunized with recombinant NP antigen. The assay was highly repeatable and specific; it detected strains of RVFV from the entire distributional range of the disease, isolated over a period of 53 years; no cross-reactivity with genetically related African phleboviruses or other members of the family Bunyaviridae was observed. In specimens spiked with RVFV, including human and animal sera, homogenates of liver and spleen tissues of domestic ruminants, and Anopheles mosquito homogenates, the sAg-ELISA detection limit ranged from log 1010 2.2 to 10 3.2 TCID 50/reaction volume. The ELISA detected NP antigen in spiked bovine and sheep liver homogenates up to at least 8 days of incubation at 37 °C whereas infectious virus could not be detected at 48 h incubation in these adverse conditions. Compared to virus isolation from sera from RVF patients and sheep infected experimentally, the ELISA had 67.7% and 70% sensitivity, and 97.97% and 100% specificity, respectively. The assay was 100% accurate when testing tissues of various organs from mice infected experimentally and buffalo foetuses infected naturally. The assay was able to detect NP antigen in infective culture supernatants 16–24 h before cytopathic effects were observed microscopically and as early as 8 h after inoculation with 10 5.8 TCID 50/ml of RVFV. This ability renders the assay for rapid identification of the virus when its primary isolation is attempted in vitro. As a highly specific, safe and simple assay format, the sAg-ELISA represents a valuable diagnostic tool for use in less equipped laboratories in Africa, and for routine differential diagnosis of viral hemorrhagic fevers.

Development and Evaluation of a Real-Time Reverse Transcription-Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Rift Valley Fever Virus in Clinical Specimens

This paper reports on the development and validation of a real-time reverse transcription-loop-mediated isothermal amplification assay (RT-LAMP) targeting the genomic large RNA segment of Rift Valley fever virus (RVFV). The set of six designed RT-LAMP primers identified strains of RVFV isolated in geographically distinct areas over a period of 50 years; there was no cross-reactivity with other genetically related and unrelated arboviruses. When testing serial sera and plasma from sheep experimentally infected with wild-type RVFV, there was 100% agreement between results of the RT-LAMP, a TaqMan-based real-time PCR, and virus isolation. Similarly, the assay had very high levels of diagnostic sensitivity and specificity when testing various clinical specimens from humans and animals naturally infected with the virus during recent outbreaks of the disease in Africa. The detection of specific viral genome targets in positive clinical specimens was achieved in less than 30 min. As a highly accurate, rapid, and very simple nucleic acid detection format, the RT-LAMP has the potential to be used in less-well-equipped laboratories in Africa and as a portable device during RVF outbreaks in remote areas, and it can be a valuable tool for the differential diagnosis of viral hemorrhagic fevers.

MassTag Polymerase Chain Reaction for Differential Diagnosis of Viral Hemorrhagic Fevers

Viral hemorrhagic fevers are associated with high rates of illness and death. Although therapeutic options are limited, early differential diagnosis has implications for containment and may aid in clinical management. We describe a diagnostic system for rapid, multiplex polymerase chain reaction identification of 10 different causes of viral hemorrhagic fevers.

Viral haemorrhagic fevers

Abstract Viral haemorrhagic fevers are viral infections that can cause shock, haemorrhage and multi-organ dysfunction. Their geographical distribution is limited by the ecology of their vectors, and many of them exist in tropical zones. The most common viral haemorrhagic fevers are not transmissible from person to person, and no viral haemorrhagic fevers are a threat to casual contacts. However, four viruses for which prevention and treatment are unreliable or not available (Crimean-Congo, Ebola, Lassa and Marburg) can be transmitted to health-care or laboratory workers. Household and health-care-related transmission is mainly limited to carers of severely ill patients, particularly patients who are highly dependent or suffering severe haemorrhage. Specialist laboratories and clinical referral centres advise on the risk assessment of suspected cases and support management of proven cases. Patients with fever after visiting viral haemorrhagic fever-endemic areas are often infected with falciparum malaria, which can cause life-threatening disease if it is not recognized and treated. Malaria should always be excluded before considering a diagnosis of viral haemorrhagic fever. If malaria or another treatable disease is not evident, or there is a definite history of direct viral haemorrhagic fever exposure, advice should be sought from an expert unit, to arrange early and safe case-management.

Viral haemorrhagic fevers—implications in intensive care

The viral haemorrhagic fevers are a group of potentially lethal infections, for which limited therapy is available and for which early diagnosis is desirable in order that meticulous isolation, contact tracing and public control measures can be instituted. It is important in these days of widespread foreign travel and integration that all clinicians especially intensivists be aware of this rare potential diagnosis in patients with organ failure, haemorrhage and a pyrexia of unknown origin. In addition these organisms have been considered to have a potential use as biological weapons. It is intended that this article will provide aid in the diagnosis, management and public health/ infectious control procedures required in the event of a patient presenting with a possible diagnosis of viral haemorrhagic fever.

Patients with suspected Lassa fever in London during 1984: problems in their management at St Thomas's Hospital.

During 1984, 23 patients in whom a diagnosis of viral haemorrhagic fever was considered presented to the accident and emergency department at St Thomas's Hospital. There were no confirmed cases of viral haemorrhagic fever. Nine patients were transferred to Coppett's Wood Hospital, the nearest specially designated high security isolation unit. Malaria was the final diagnosis in 14, and in six this diagnosis was confirmed only after examining repeated smears at Coppett's Wood Hospital. Transferral of patients to such units is time consuming, expensive, and often unnecessary. Specially designated isolation units in district general hospitals and all teaching hospitals would simplify and improve the care not only of patients with a possible viral haemorrhagic fever but also patients with tuberculosis, multiply resistant staphylococcal infections, and viral infections that may be hazardous if transmitted to immunocompromised patients.