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RNA-Based Vaccines for Infectious Disease
Published in Yashwant V. Pathak, Gene Delivery Systems, 2022
Deepa Dehari, Aiswarya Chaudhuri, Sanjay Singh, Ashish Kumar Agrawal
Zika virus is an evolving virus that poses a significant social health risk to humans. Although the majority of patients are symptomless or have mild, self-limiting symptoms, a limited proportion of individuals develop significant abnormalities, like congenital anomalies in the growing fetus of infected pregnant mothers and neurological dysfunction (e.g., Guillain-Barré syndrome). Zika virus is an arbovirus that corresponds to the Flaviviridae family of viruses, which also involves dengue, West Nile, and yellow fever viruses. The Zika virus has a single-stranded, +ve sense RNA genome that encrypts structural and non-structural proteins (capsid, precursor membrane [prM], and envelope [E]). The genetic code is transcribed into a single polypeptide, which is then sliced into specific proteins using proteolytic cleavage. The prM, E, and non-structural proteins are the most divergent from other flaviviruses in terms of pattern. East African, West African, and Asian Zika virus lineages have been identified [53–54].
Microbiological, West Nile Virus, and Lyme Disease
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
West Nile virus (WNV) emerged from its origin in 1937 in Africa (Uganda) into Europe, the Middle East, west and central Asia, and associated islands. It is a Flavivirus (family Flaviviridae) with more than 70 identified viruses. Serologically, it is a JE virus antigenic complex similar to SLE, JE, and Murray Valley encephalitis viruses. Similar to other encephalitides, it is cycled between birds and mosquitoes and transmitted to mammals (including horses) and man by infected mosquitoes. WNV might be described in one of four illnesses: West Nile fever (WNF) might be the least severe and is characterized by fever, headache, tiredness, and aches or a rash; like the “flu.” This might last a few days or several weeks. At least 63% of patients report symptoms lasting over 30 days, with the median being 60 days. The other types are grouped as “neuroinvasive disease” which affects the nervous system. West Nile encephalitis affects the brain and West Nile meningitis (WNM, meningoencephalitis) causes an inflammation of the brain and membrane around it (CDC).
Modeling the Transmission Dynamics of Zika Virus
Published in Ranjit Kumar Upadhyay, Satteluri R. K. Iyengar, Spatial Dynamics and Pattern Formation in Biological Populations, 2021
Ranjit Kumar Upadhyay, Satteluri R. K. Iyengar
Recently, the rapid spread of Zika virus has gained a lot of attention among the public and the Governments. Zika virus infection can lead to some serious neurological complications like the following: (i) among the newly born babies, it may lead to a birth defect where a baby’s head and/or brain is smaller than expected. This condition is termed microcephaly. (ii) It may lead to a neurological disorder that could lead to paralysis and death, which is called Guillain-Barre syndrome [76]. Since the effects of contracting Zika virus in the first few days are similar to those of dengue fever, it was thought of as mild dengue. World Health Organization (WHO) declared the re-emergence of Zika virus as a Public Health Emergency of International Concern on February 1, 2016 [56]. WHO called on the global research and product development (R&D) communities to prioritize the development of preventative and therapeutic solutions [111]. In response, the R&D communities produced 45 vaccine candidates. Several candidates of vaccines have advanced beyond pre-clinical studies in animals and entered phase 1 human trials [41,42]. Of those, two vaccines have entered phase 2 trials [112,113]. Zika is a single-stranded RNA flavivirus and belongs to the Flaviviridae family [68]. The virus is genetically related to many other viruses that are responsible for encephalitis, chikungunya, dengue, Japanese encephalitis, West Nile fever, and yellow fever in humans [48,70,105]. The main vectors (mosquitoes) that are responsible for the transmission of Zika virus are Aedes aegypti and Aedes albopictus [6]. These mosquitoes are mostly found in tropical and subtropical regions [91]. Zika virus was first discovered in rhesus monkeys in 1947 while researchers were studying yellow fever in Zika Forest, Uganda. It was isolated from Aedes africanus mosquitoes in the subsequent year [36]. In 1952, Zika virus was first isolated from a captive rhesus monkey stationed in the Zika forest near Entebbe, Uganda [35]. The virus was also isolated from a batch of wild mosquitoes. No virus was recovered from tissues other than the brains of infected mice. Zika virus is a relatively unstable agent in suspensions [35]. In 1954, MacNamara [71] reported three cases of Zika infection among humans during an epidemic of jaundice (suspected of being yellow fever) in Eastern Nigeria. One of the patients was infected by Zika virus. The other two patients exhibited a rise in the titer of serum antibodies against this virus. In 1954, the first human isolation was recorded in Nigeria [71,91]. For decades, the viral infection was occasionally reported in Africa and Southeast Asia [48,51].
Environmental health effects attributed to toxic and infectious agents following hurricanes, cyclones, flash floods and major hydrometeorological events
Published in Journal of Toxicology and Environmental Health, Part B, 2019
Timothy B. Erickson, Julia Brooks, Eric J. Nilles, Phuong N. Pham, Patrick Vinck
Another related threat is Zika virus, a mosquito-borne virus in the genus Flavivirus of the Flaviviridae family that is transmitted by Aedes aegypti and Ae. albopictus mosquitoes, with the potential for rapid spread (Kraemer et al. 2019). Zika is a single-stranded RNA virus that is closely related to dengue virus, yellow fever virus, and West Nile virus (Kraemer et al. 2019). Predisposing factors such as climate change, globalization, population rise, and increased urbanization have contributed to the spread of these viruses, posing pandemic threats (Boyer et al. 2018; Kraemer et al. 2019).