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Order Articulavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Currently licensed popular inactivated influenza vaccines are composed of formalin-treated whole virus or detergent-split viral components. The vaccine strains are selected based on epidemiologic and antigenic considerations of circulating human strains and their anticipated prevalence during the coming year. To obtain high-yield vaccine seed viruses, the chosen strains are adapted to grow in embryonated eggs, or reassortant viruses are generated containing HA and NA genes of current strains and genes for internal proteins of influenza A/Puerto Rico/8/34 (H1N1) virus, which confer high growth capacity in eggs (Robertson et al. 1992).
Yellow Fever
Published in Rae-Ellen W. Kavey, Allison B. Kavey, Viral Pandemics, 2020
Rae-Ellen W. Kavey, Allison B. Kavey
In response to recurrent and increasingly large ongoing epidemics on two continents, the WHO recommends the traditional triad of surveillance, vaccination, and vector control. However, the global emergency YF vaccine stockpile is depleted, with not enough vaccine to even cover Angola’s population during that recent epidemic. The production of new vaccine using the current method of embryonated chicken eggs is slow and limits the capability to rapidly produce large vaccine quantities in response to an outbreak. It is therefore highly unlikely that sufficient YF doses would be available for an effective emergency YF outbreak response anywhere in the world. Any vaccination program must be coupled with the development of systems that can support a rapid outbreak response. These include strengthening laboratory capacity, the ability to carry out epidemiological and entomological investigations, and emergency measures to interrupt transmission. Vector control will require destruction of urban mosquito breeding sites and public education about mosquito avoidance and elimination of domestic breeding sites. Clearly, new options are also required to address the threat of yellow fever infection in non-immunized travelers returning from a country with endemic or epidemic disease.
Influenza
Published in James M. Rippe, Lifestyle Medicine, 2019
All influenza viruses are capable of infecting humans. Influenza A viruses are capable of infecting many animal species as well, including swine, horses, marine mammals, and birds. Wild birds, particularly aquatic birds, are the natural hosts of influenza A virus. Influenza viruses of low pathogenicity do not necessarily lead to clinical illness in the birds they infect, but viruses that cause severe disease and death in birds do exist (e.g., H5N1). The isolation of influenza virus from ferrets in the laboratory took place in 1933, and ferrets continue to be the ideal animal model for the study of influenza. Virus culture in embryonated hen eggs was accomplished in 1936. These advancements allowed the study of virus properties and led to the development of vaccines in the 1940s. Animal cell culture systems for propagating virus in tissue culture were developed in the 1950s.
Immunoinformatics driven construction of multi-epitope vaccine candidate against Ascaris lumbricoides using its entire immunogenic epitopes
Published in Expert Review of Vaccines, 2021
Rimanpreet Kaur, Naina Arora, Suraj Singh Rawat, Anand Kumar Keshri, Neha Singh, Sumit Kumar Show, Pramod Kumar, Amit Mishra, Amit Prasad
Ascaris resides in jejunum of human small intestine but it has ability to migrate to other body parts such as lungs, liver, gallbladder, and pancreas [6]. Adult worms reside in intestinal lumen of human host and has the potential to produce 200,000 eggs daily which are defecated/excreted along with feces. These eggs can survive under extreme environmental conditions. The fertilized eggs are transformed into embryonated eggs which develop into larvae. When the climate is conducive, like moderate warmth (25–30°C temperature), high moisture content and adequate supply of oxygen, these fertilized eggs molt and embryonate in a span of 15–35 days to achieve infective stage. The infective eggs carry a 2nd stage larva, coiled within its own eggshell. The infective eggs reach human host due to consumption of contaminated food having embryonated eggs. In gastrointestinal tract they get transformed into larvae and circulate to the lungs and other organs. From the lungs, larvae are coughed out or swallowed sometimes and thus they re-enter the gastrointestinal tract. Maturation process proceeds in the small intestines [7,8]. The Ascariasis symptoms varies from asymptomatic phase to severe symptomatic phase with warning signs of infection, these signs increase with increasing parasitic burden, which leads to intestinal obstruction, loss of appetite, intestinal bleeding, and malnutrition in children [9].
Advances in influenza virus-like particles bioprocesses
Published in Expert Review of Vaccines, 2019
Laurent Durous, Manuel Rosa-Calatrava, Emma Petiot
Currently, influenza vaccines are predominantly prepared from virus propagation in embryonated hen’s eggs. Such production process suffers from different shortfalls, meaning the process is not satisfactory to face a pandemic crisis. One of its main drawbacks is the duration of the production process, which requires annually up to six months from WHO strain selection to the delivery of millions of vaccine doses [1]. Lessons learned from the recent swine and avian pandemic crises have led to several initiatives in order to ensure optimal and rapid responses to upcoming pandemic outbreaks. One of the most promising alternative vaccination strategies is based on Virus-like particles (VLPs) production. Such strategy is flexible and gives access to a large variety of processes and cell production platforms (see Table 1).
Universal influenza virus vaccines: what needs to happen next?
Published in Expert Opinion on Biological Therapy, 2019
Cecilia Trucchi, Chiara Paganino, Daniela Amicizia, Andrea Orsi, Valentino Tisa, Maria Francesca Piazza, Giancarlo Icardi, Filippo Ansaldi
For example, the extensive available safety data regarding the IV vaccines that are administered to humans are based on the administration of billions of doses that have been passaged in embryonated chicken eggs. However, it is necessary that these eggs be sourced from flocks that are free from specific pathogens and certified as ‘clean’ in order to avoid adventitious agents. Furthermore, IVs appear to mutate more often at the level of the receptor binding site and undergo selection more readily when passaged in embryonated chicken eggs than in cells cultured in vitro [49–53]. This could potentially affect vaccine efficacy, as has been observed in animal models [54]. In particular, the vaccine virus could undergo small protein changes during the multiple passages required by egg-based production, a process that facilitates viral replication. In this regard, Zost et al. reported that during the 2016–17 influenza season in the US, HA glycosylation at antigenic site B during egg adaptation led to a loss of effectiveness of the vaccine virus [55]. In addition, Wu et al. described an egg-adaptive substitution ‘L194P’ in the H3N2 vaccine strain that altered the receptor-binding mode and specificity [56].