Water-based disease and microbial growth *
Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse in Routledge Handbook of Water and Health, 2015
Anisakis spp. and Pseudoterranova spp. are roundworms (helminths) which infect marine mammals, fish and crustaceans. Adult worms live in the stomach of marine mammals and eggs from these worms pass into the sea where they become embryonated and develop into second stage larvae. They then hatch and become free living. They are taken up by crustaceans and develop into third stage larvae which become infectious to fish and squid. When the fish die the larvae migrate to muscle tissue and can pass through predation from fish to fish. Infective third stage larvae develop to an adult stage in pinniped mammals (e.g. seals). Humans are an accidental host for third or fourth stage larvae through the consumption of raw fish, and freezing the fish is thought to prevent infection. If humans eat fish contaminated with third stage larvae these molt twice and develop into adult worms, penetrating into the oesophagus, gastric or intestinal mucosa and causing abdominal pain, nausea, vomiting, abdominal distension, blood in the stools and mild fever. Worms and eggs are not known to be excreted in human faeces and diagnosis is by gastroscopy. Treatment is by endoscopic removal of the worms.
Yellow Fever
Rae-Ellen W. Kavey, Allison B. Kavey in Viral Pandemics, 2020
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.
Microbiological Diagnosis of Viral Diseases
Nancy Khardori in Bench to Bedside, 2018
Embryonated hen eggs were commonly used for virus isolation till the advent of cell culture. The milieu provided by the embryonated egg supports the growth of many viruses infecting humans. Various routes are available for virus cultivation, including the amniotic cavity (primary isolation of influenza virus), allantoic cavity, yolk sac (arboviruses like the yellow fever vaccine strain 17-D) and chorioallantoic membrane (CAM; cultivation of pox viruses and HSV). Currently, the major use of this technique is in the mass scale production of seasonal influenza vaccines using the allantoic route.
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].
In silico, in ovo and in vitro antiviral efficacy of phosphorylated derivatives of abacavir: an experimental approach
Published in Journal of Receptors and Signal Transduction, 2020
Kuruva Chandra Sekhar, Chintha Venkataramaiah, Chamarthi Naga Raju
Embryonated chicken eggs were obtained from Poultry Division, Sri Venkateswara Veterinary University, Tirupati, and were incubated at 37 °C in an egg incubator. Two commonly employed and comparatively safe animal viruses Newcastle Disease virus (NDV) and the Blue tongue virus (BTV) were used in this study. Lasota strain of NDV and BTV were obtained from Department of Virology, Sri Venkateswara University, Tirupati. Titers of the NDV were determined by inoculating chick embryonating eggs and calculated median egg infectious (EID50) of the virus as per the method of Young et al. [16]. From this, 100 EID50/0.1 ml of the viral stock was prepared to proceed for the experiments. This viral stock was stored at −40 °C.
Current vaccine approaches and emerging strategies against herpes simplex virus (HSV)
Published in Expert Review of Vaccines, 2021
Vindya Nilakshi Wijesinghe, Isra Ahmad Farouk, Nur Zawanah Zabidi, Ashwini Puniyamurti, Wee Sim Choo, Sunil Kumar Lal
Different routes and strategies have been adopted to develop a suitable HSV vaccine with hopes of forestalling future outbreaks. One of the first ever approaches taken in HSV vaccine development was the inactivated vaccine strategy by using formalin-treated tissues of HSV-infected animals [35]. Over time, researchers developed newer strategies to prepare and inactivate the virus such as growing the virus in embryonated eggs and cell culture using physical and/or chemical means for inactivation though these vaccines lacked adequate efficacy [57]. In this section, some of these approaches and the current state of vaccine development are covered.
Related Knowledge Centers
- Microbiology
- Ovipositor
- Parasitology
- Virology
- Embryo
- Reproductive System
- Microbiological Culture
- Zygote
- Egg Incubation