Search results for "Virus Shedding"
showing 10 items of 12 documents
Experimental Evolution Reveals a Genetic Basis for Membrane-Associated Virus Release
2021
Many animal viruses replicate and are released from cells in close association to membranes. However, whether this is a passive process or is controlled by the virus remains poorly understood. Importantly, the genetic basis and evolvability of membrane-associated viral shedding have not been investigated. To address this, we performed a directed evolution experiment using coxsackievirus B3, a model enterovirus, in which we repeatedly selected the free-virion or the fast-sedimenting membrane-associated viral subpopulations. The virus responded to this selection regime by reproducibly fixing a series of mutations that altered the extent of membrane-associated viral shedding, as revealed by fu…
Pulmonary cytomegalovirus (CMV) DNA shedding in allogeneic hematopoietic stem cell transplant recipients: Implications for the diagnosis of CMV pneum…
2019
Highlights • CMV DNA is frequently detected in BAL fluid specimens from allo-HSCT. • CMV DNA detection in BAL fluids is comparable across pneumonia etiologies. • CMV DNA loads in BAL fluids are comparable across pneumonia etiologies. • CMV DNA load in BAL may predict attributable-pneumonia mortality.
Nasal immunization of mice with a rotavirus DNA vaccine that induces protective intestinal IgA antibodies
2004
International audience; DNA vaccination using a plasmid encoding the rotavirus inner capsid VP6 has been explored in the mouse model of rotavirus infection. BALB/c mice were immunized with a VP6 DNA vaccine by the intramuscular, nasal and oral routes. VP6 DNA vaccination by the nasal and oral routes induced the production of anti-VP6 IgA antibodies by intestinal lymphoid cells. Intramuscular DNA injection stimulated the production of serum anti-VP6 IgG but not serum anti-VP6 IgA antibodies. Protection against shedding of rotaviruses in stools after oral challenge with the murine EDIM rotavirus strain was investigated in the immunized mice. A significant reduction in the level of rotavirus a…
Microbiota Depletion Promotes Human Rotavirus Replication in an Adult Mouse Model
2021
Intestinal microbiota-virus-host interaction has emerged as a key factor in mediating enteric virus pathogenicity. With the aim of analyzing whether human gut bacteria improve the inefficient replication of human rotavirus in mice, we performed fecal microbiota transplant (FMT) with healthy infants as donors in antibiotic-treated mice. We showed that a simple antibiotic treatment, irrespective of FMT, resulted in viral shedding for 6 days after challenge with the human rotavirus G1P[8] genotype Wa strain (RVwa). Rotavirus titers in feces were also significantly higher in antibiotic-treated animals with or without FMT but they were decreased in animals subject to self-FMT, where a partial re…
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.)
2010
Abstract Background For more than three decades, diseases caused by salmonid alphaviruses (SAV) have become a major problem of increasing economic importance in the European fish-farming industry. However, experimental infection trials with SAV result in low or no mortality i.e very different from most field outbreaks of pancreas disease (PD). This probably reflects the difficulties in reproducing complex biotic and abiotic field conditions in the laboratory. In this study we looked at the relationship between SAV-infection in salmon and sub-lethal environmental hypoxia as a result of reduced flow-through in tank systems. Results The experiment demonstrated that constant reduced oxygen leve…
Replication of Human Norovirus in Mice after Antibiotic-Mediated Intestinal Bacteria Depletion
2022
Human noroviruses (HuNoVs) are the main cause of acute gastroenteritis causing more than 50,000 deaths per year. Recent evidence shows that the gut microbiota plays a key role in enteric virus infectivity. In this context, we tested whether microbiota depletion or microbiota replacement with that of human individuals susceptible to HuNoVs infection could favor viral replication in mice. Four groups of mice (n = 5) were used, including a control group and three groups that were treated with antibiotics to eliminate the autochthonous intestinal microbiota. Two of the antibiotic-treated groups received fecal microbiota transplantation from a pool of feces from infants (age 1-3 months) or an au…
Platinum chloride-based viability RT-qPCR for SARS-CoV-2 detection in complex samples.
2021
Isolation, contact tracing and restrictions on social movement are being globally implemented to prevent and control onward spread of SARS-CoV-2, even though the infection risk modelled on RNA detection by RT-qPCR remains biased as viral shedding and infectivity are not discerned. Thus, we aimed to develop a rapid viability RT-qPCR procedure to infer SARS-CoV-2 infectivity in clinical specimens and environmental samples. We screened monoazide dyes and platinum compounds as viability molecular markers on five SARS-CoV-2 RNA targets. A platinum chloride-based viability RT-qPCR was then optimized using genomic RNA, and inactivated SARS-CoV-2 particles inoculated in buffer, stool, and urine. Ou…
Initial viral load and decay kinetics of SARS-CoV-2 lineage B.1.1.7 in the upper respiratory tract of adults and children
2021
We read with interest the systematic review published by Walsh et al. in the Journal of Infection,1 focusing on the dynamics of SARS-CoV-2 RNA at the upper respiratory tract (URT). In this context, a novel SARS-CoV-2 variant lineage (B.1.1.7), first detected in the UK at the end of 2020 has transmission advantage over other lineages.2 Increased transmissibility of the B.1.1.7 variant has been linked to enhanced ACE2 affinity3 allegedly resulting in higher viral loads in URT, an observation that has been reported in some,3, 4, 5, 6 but not all7 large series published to date. In addition, longer duration of SARS-CoV-2 RNA shedding in URT has been reported in individuals infected by the B.1.1…
Are licensed canine parvovirus (CPV2 and CPV2b) vaccines able to elicit protection against CPV2c subtype in puppies?: A systematic review of controll…
2015
Severe gastroenteritis caused by canine parvovirus type 2 (CPV2) is a serious life-threatening disease in puppies less than 4-months of age. The emergence of new variants has provoked some concern about the cross-protection elicited by licensed canine parvovirus modified-live type 2 (CPV2) and type 2b (CPV2b) vaccines against the most recent subtype CPV2c. A systematic review was carried out to assess the efficacy of commercial vaccines. We conducted a literature search of Pub Med/MEDLINE from January 1990 to May 2014. This was supplemented by hand-searching of related citations and searches in Google/Google Scholar. Controlled clinical trials in which vaccinated puppies were challenged wit…
Enteric calicivirus and rotavirus infections in domestic pigs
2009
SUMMARYWe report the prevalence of rotavirus and calicivirus infections, along with their respective association with diarrhoea in the porcine population of the region of northern Spain. A total of 221 samples were collected at random from different farms in the region and from the main slaughterhouse facility in the city of Zaragoza. Faecal samples were scored as diarrhoeic or normal and grouped into five groups to match general farm management and age criteria: group I (suckling 0–4 weeks), group II (weaning >4–8 weeks), group III (transition >8–16 weeks), group IV (fattening >16–24 weeks) and group V (adults >24 weeks). Group A rotavirus detection and caliciviruses were inves…