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Infectious Optic Neuropathies
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Imran Rizvi, Ravindra Kumar Garg
Dengue virus is a flavivirus. Aedes mosquitos are responsible for its transmission in humans. The clinical spectrum of dengue fever ranges from mild self-limiting febrile disorder to severe life-threatening clinical syndromes, like dengue hemorrhagic fever and dengue shock syndrome. Ophthalmological complications, in dengue fever, occur in the form of subconjunctival hemorrhage, anterior uveitis, vitritis, retinal hemorrhages, retinochoroiditis, choroidal effusion, panophthalmitis and optic neuropathies.26 The reported incidence of optic neuropathy in dengue is up to 1.5%.27 Optic nerve involvement manifests with optic neuritis, optic disc swelling or neuroretinitis. Vision loss is often self-limiting.
Order Amarillovirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The majority of known members in the genus Flavivirus are arthropod borne, and many are important human pathogens such as highly dangerous dengue (DENV serotypes 1–4), Japanese encephalitis (JEV), tick-borne encephalitis (TBEV), West Nile (WNV), yellow fever (YFV), and Zika (ZIKV) viruses. Among the flaviviruses, DENV-1–4, WNV, and JEV may cause millions of infections and tens of thousands of deaths each year. Mammals and birds are the usual primary hosts, in which infections range from asymptomatic to severe or fatal hemorrhagic fever or neurological disease. Other members of the Flavivirus genus cause economically important diseases in domestic or wild animals, as reviewed by Simmonds et al. (2012, 2017).
West Nile Virus: The Silent Neuro-Invasive Terror
Published in Jagriti Narang, Manika Khanuja, Small Bite, Big Threat, 2020
Vinod Joshi, Annette Angel, Bennet Angel, Neelam Yadav, Jagriti Narang, Surender Yadav
Flavivirus WNV is transmitted when infected Culex mosquitoes bite. Outbreaks of WNV have been reported in the United States and other countries. The virus causes severe fever and several neuroinvasive diseases in humans. Therefore, it is necessary to mitigate the serious issues of proper management of WNV outbreaks. Various molecular techniques such as PCR-based techniques and biosensing techniques have been used for the detection of WNV, though nano-based approaches have not been developed. Hence, future research should be focused to develop more refined nano-based technologies and miniaturized techniques that can provide an effective platform for the investigation of WNV, which must be fast, economic, transportable, and efficient in comparison to serological and molecular techniques.
Dengue and zika seropositivity, burden, endemicity, and cocirculation antibodies in Nigeria
Published in Annals of Medicine, 2023
Peter Asaga Mac, Markos Tadele, Philomena E. Airiohuodion, Thilini Nisansala, Shaistha Zubair, Jude Aigohbahi, Chukwuma Anyaike, Raman Velayudha, Axel Kroeger, Marcus Panning
A total of 871 participants were recruited from three geographical areas of Nigeria:17.5% (152/871) from southern Nigeria (Abia), 34.4% (300/871) from northern Nigeria (Kaduna), and 48.1% (419/871) from central Nigeria (Nasarawa). The study population had an age range of 0 months to 80 years, with a mean age of 36.5 years. Female participants comprised 71% (619/871) of the study population, while male participants constituted 29% (252/871). Approximately 28.1% (14/167) of the study participants who showed signs and symptoms of antibody seropositivity against ZIKV had headaches, whereas 91.0% of those with headaches had signs and symptoms of DENV seropositive antibodies. ZIKV (fever, 29.3%) DENV (fever, 97.4%), ZIKV (Exanthema, 12.6%), DENV (Exanthema, 28.0%), ZIKV (Abdominal pain, 60.5%), DENV (Abdominal pain, 29.5%). The study cohort exhibited varied but similar clinical signs and symptoms of flaviviruses across all three study regions (Table 1). The overall IgG antibody seropositivity against flavivirus-DENV was 44.7% (389/871); 95% CI (41.41–47.99), while ZIKV-flavivirus was 19.2% (167/871); 95% CI (0.16–0.21), whereas the antibody seropositivity against one or more flaviviruses (either DENV or ZIKV participants who were or who showed serological evidence against DENV and ZIKV at sampling period or time) cocirculation was 6.2%5 (54/871); 95% CI (0.6–0.7) (Table 2).
Diagnostic approaches for dengue infection
Published in Expert Review of Molecular Diagnostics, 2023
Gaythri Thergarajan, Shamala Devi Sekaran
The primary challenge is that the pathogenesis of dengue is not entirely understood and multiple sequential infections can occur. Additionally, primary and secondary infection statuses and cross-reactivity among flaviviruses make diagnosis even more complicated. Another obstacle is translating laboratory research into real-world technological applications, including the development of diagnostic devices for viral detection, which remains a challenge to be addressed in the future. Virus isolation and amplification are not a choice for multiple reasons of cost, time, interpretation of primary or secondary as well as potential cross contamination. However, it is hoped that using more advanced technologies or automated machines this procedure can be made more easily available and integrated such that it can be done within a day. Antigen determination, though simple and rapid is of lower sensitivity, highly cross-reactive and has problems with immobilization. With antibody detection, though confirmatory with pairs can differentiate primary and secondary when so designed. Many have moved toward biosensors, but these have complex pre-treatment preparations, expensive sensors to be fabricated, low stability and repeatability and none have yet to be efficiently validated.
Challenges with the discovery of RNA-based therapeutics for flaviviruses
Published in Expert Opinion on Drug Discovery, 2023
Mei-Yue Wang, Rong Zhao, Yu-Lan Wang, De-Ping Wang, Ji-Min Cao
In the last two decades of the 21st century, there have been several viral outbreaks caused by flavivirus family members, posing a great threat to public health worldwide [1]. To date, flaviviruses are still spreading worldwide, leading to the loss of human lives and economic damage. Flaviviruses are positive-sense, single-stranded RNA viruses, including Dengue virus (DENV), Zika virus (ZIKV), West Nile virus (WNV), tick-borne encephalitis virus (TBEV), and Japanese encephalitis virus (JEV). The translation of viral RNA generates a polyprotein that is cleaved into seven non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) and three structural proteins, namely the capsid (C), envelope (E), and pre-membrane/membrane (prM/M) proteins (Figure 1) [2–4]. The key steps in the viral life cycle, including viral entry, endocytosis or trafficking, viral uncoating, replication, transcription, translation, and viral particle assembly, represent potential therapeutic targets [5]. There are two fundamental types of antiviral therapeutics: direct-acting antivirals that target the virus itself and host-factor antivirals that target critical segments of the host cell [6].