Diagnostic Approach to Fulminant Hepatitis in the Critical Care Unit
Cheston B. Cunha, Burke A. Cunha in Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Ebola, also called Ebola hemorrhagic fever, is a viral hemorrhagic fever of humans caused by the Ebola virus, a member of the Filoviridae family. It is spread by direct contact with body fluids, such as blood, stool, and vomitus of an infected human. Ebola is characterized by fever, fatigue, vomiting, diarrhea, rash, kidney, liver failure, and occasionally bleeding. It is associated with a high case fatality rate of 54.7%, with fatality rates reported to increase with age and high viral load [28]. Patients with Ebola virus disease were found to have AST/ALT levels of more than five times the upper limit of normal and, in severe cases, levels of more than 15 times the upper limit of normal [29]. Diagnosis of Ebola can be made by serum PCR on blood drawn within 3 days of the onset of symptoms. A rapid chromatographic immunoassay (ReEBOV) that detects Ebola virus antigen can provide results within 15 minutes; however, this has been associated with false-positive results in 10% of patients who tested negative by PCR [30]. On postmortem liver biopsy, hepatocellular necrosis with minimal inflammation is the primary histological finding. There is no specific therapy for Ebola, and treatment includes fluids and supportive care.
Chemical and Biological Threats to Public Safety
Frank A. Barile in Barile’s Clinical Toxicology, 2019
Viral hemorrhagic fevers (VHF) are a clinically related group of viral diseases with a diverse etiology. The family of Filoviridae includes the Marburg and Ebola viruses. Similarly, the family of Bunyaviridae includes the hantavirus and bunyavirus (which primarily causes encephalitis in humans). All are RNA viruses endemic in Africa and with the exception of the bunyavirus, cause severe or fatal hemorrhagic fevers. The condition is characterized by acute onset of fever, headache, generalized myalgia, conjunctivitis, and severe prostration, followed by various hemorrhagic symptoms. The organism facilitates the destruction of endothelial cells, leading to vascular injury and increased capillary permeability, leukopenia, and thrombocytopenia. Antiviral therapy has not been shown to be clinically useful.
Virus
Joseph R. Masci, Elizabeth Bass in Ebola, 2017
The family Filoviridae comprises two genera: the Ebola and the Marburg viruses. There are five recognized species in the genus Ebola. These are Zaire ebolavirus (ZEBOV): First recognized in 1976 in a teacher in Zaire (now Democratic Republic of Congo) who presented with symptoms suggestive of malaria followed by a diffuse rash as well as nausea, vomiting, and diarrhea, an illness similar to that seen in the 2014–2016 West African outbreak.Sudan ebolavirus (SEBOV): Also first identified in 1976 in Sudan.Reston ebolavirus (REBOV): Recognized in 1989 in an outbreak among macaque monkeys. REBOV has also been identified in affected animals imported from the Philippines. REBOV is closely related to SEBOV and its appearance in the Philippines is unexplained.Cote d’Ivoire ebolavirus (CIEBOV): Isolated in 1994 from chimpanzees in the Ivory Coast.Bundibugyo ebolavirus: Identified in Uganda in 2008.
The role of sialic acid-binding immunoglobulin-like-lectin-1 (siglec-1) in immunology and infectious disease
Published in International Reviews of Immunology, 2023
Shane Prenzler, Santosh Rudrawar, Mario Waespy, Sørge Kelm, Shailendra Anoopkumar-Dukie, Thomas Haselhorst
Ebola viruses belong to the Filoviridae family and consist of many strains which are capable of causing hemorrhagic fever [27]. Ebola viruses also utilize dendritic cells and macrophages to disseminate to the lymph nodes, liver and spleen [88]. Ebola virus dendritic cell entry involves several steps requiring multitude of receptors. DC-SIGN mediates attachment of the Ebola virus to dendritic cells by glycoprotein recognition, meanwhile TIM/TAM receptors bind phosphatidylserine on the membrane of virus facilitating viral cell entry by means of apoptotic mimicry [89–91]. From here Ebola viruses enters the cell after macropinocytosis and the viral glycoprotein is cleaved using cellular proteases like cathepsin B [27, 92]. The cleavage allows for glycoprotein recognition by endosome receptor Niemann-Pick C1, which allows the virus to enter the cytoplasm [93, 94]. It was recently discovered that in a similar way to HIV-1, ebola virus buds from host cells and incorporates GM1 gangliosides which bind Siglec-1 [27]. The role of Siglec-1 in attachment and entry of Ebola virus is poorly understood, but it has been shown that anti-Siglec-1 antibodies are able to hinder viral entry and that Siglec-1 is more prominent to the entry of the virus than other well-known receptors like DC-SIGN [27]. Currently, there are studies underway to create vaccines for Zaire ebolavirus (ZEBOV), which is the species responsible for a recent outbreak in West Africa. However, there are other species which will not be covered by vaccine efforts and Siglec-1 may represent an important therapeutic target [27].
The roles of epidermal growth factor receptor in viral infections
Published in Growth Factors, 2022
So far, there is no specific drug to treat DENV infection. Bekerman et al. (2017) have revealed the antiviral activity of combined treatment of erlotinib and sunitinib in two DENV-infected IFN-α/β and IFN-γ receptor-deficient murine models, AG129 and AG-B6. Erlotinib is a reversible EGFR inhibitor approved for the treatment of metastatic NSCLC and pancreatic cancer, whereas sunitinib is an ATP-competitive multitargeted tyrosine kinase inhibitor approved for the treatment of renal cell carcinoma, gastrointestinal stromal tumour, and pancreatic neuroendocrine tumour (Shukla et al. 2009; Blumenthal et al. 2012). Prophylactic and daily combined treatment of erlotinib and sunitinib at 30 mg/kg respectively resulted in 11-fold reduction in DENV viremia in infected AG-B mice. This combined treatment also reduced morbidity and mortality in AG-129 and AG-B6 mice infected with lethal DENV inoculum. In addition to DENV, Bekerman et al. also demonstrated that the combined treatment inhibited Ebola virus (EBOV) infection in vivo. EBOV is one of the members of family Filoviridae that causes haemorrhagic fever associated with 50–90% human mortality. It is an enveloped virus that consists of non-segmented, single stranded and negative-sense RNA genome (Lee et al. 2008). Prophylactic and daily treatment of erlotinib and sunitinib at 45 and 5 mg/kg respectively reduced morbidity and mortality in EBOV-infected mice, as evidenced by greater weight gain and 50% survival (Bekerman et al. 2017). However, little is known on the role of EGFR in EBOV infection.
Emerging Human Coronavirus Infections (SARS, MERS, and COVID-19): Where They Are Leading Us
Published in International Reviews of Immunology, 2021
The animal origin of CoVs was hypothesized soon after the emergence of SARS-CoV infection in humans in China in November 2002 and the screening of small animals in the live-animal market of Guangdong district of the China identified the presence of SARS-CoV RNA in the masked palm civets (Paguma larvata) and a raccoon dog (Nyctereutes procyonoides) (Figure 1) [21–23]. Furthermore, SARS-CoV was reported in the masked palm civets served in the restaurant of Guangzhou of China and 2 out of 4 patients were working as waitresses there [24]. Even animal traders from Guangzhou and Guangdong had showed the presence of IgG antibodies against SARS-CoV in the circulation upon serological testing [25]. The antibodies against SARS-CoV in vegetable traders and control groups were absent. However, these animals in their wild environment and farms having no exposure to the live-animal market animals did not show the evidence of presence of SARS-CoV (Figure 1) [26]. On the other hand, bats are known as potential reservoirs for more than 200 viruses (most of them are RNA viruses, including (Henipaviruses (Hendra and Nipah virus), Ebola, and Marburg virus of Filoviridae family, Influenza A virus of Orthomyxoviridae family, Hantavirus of Bunyaviridae family, Lyssavirus (includes Rabies Virus), and CoVs also) responsible to cause infections in humans [27,28].
Related Knowledge Centers
- Ebolavirus
- Marburg Virus
- Mononegavirales
- Viral Hemorrhagic Fever
- Virus
- Zaire Ebolavirus
- Select Agent
- Biosafety
- Lloviu Virus
- Mengla Dianlovirus