Marine Wasniewski

Serological surveillance relies on blood sampling for antibody detection, but collection is invasive and logistically demanding. This study evaluated alternative biological matrices and assessed a microsphere immunoassay (MIA) as a detection method. Samples were retrieved from previous studies involving SARS-CoV-2-infected hamsters.Plasma, dried blood on filter paper, heart, spleen, rectal swabs and feces were screened for SARS-CoV-2 IgG and IgA by MIA, confirmed by ELISA and viral seroneutralization test (vSNT).IgG were consistently detected by MIA in plasma, blood on filter paper, heart and spleen. By MIA, rectal swabs yielded 62/191 IgG-positive and 44/191 IgA-positive. Only 7/144 fecal samples were IgG-positive by MIA. ELISA and vSNT were variable for mucosal matrices.Heart, spleen and dried blood on filter paper are reliable alternatives to plasma. Rectal swabs and feces show promise as minimally or non-invasive samples, though collection and storage protocols require optimization. MIA proved sensitive and robust across all matrices.

Several brands of anti-rabies vaccines (ARVs) are used for dog vaccination in Sri Lanka, which have shown major differences in their potency levels. This comparative study was conducted to determine humoral immune response of these ARVs using 2 different animal species. The reliability of an enzyme-linked immunosorbent assay (ELISA) antibody kit was assessed in comparison to the standard Fluorescent Antibody Virus Neutralization (FAVN) test. The laboratory animal study was conducted using 3–4 months old sero-negative New Zealand White rabbits. Nine vaccines from 7 producers were tested including 8 monovalent inactivated ARVs: Canvac R® single-dose and multi-dose, Nobivac® Rabies, Rabies Killed® Vaccine, Rabisin®, Defensor 3®, Raksharab® single-dose and multidose, and one bivalent inactivated ARV, Nobivac® RL. Second part was conducted in field dogs. Four vaccines with the highest potencies were selected for this field dog study. Animals were vaccinated subcutaneously with one dose of a selected ARV. Day 0 blood samples were collected just before the vaccination and Day 7, Day 14, and Day 30 samples from rabbits and Day 30 samples from dogs were collected post-vaccination. Significant differences of humoral immune response between different vaccines brands were observed in both animal species. The coefficient of concordance between the FAVN test and the ELISA was 54.6% and 85.3% for rabbits and dogs respectively. The overall results showed that ARVs with proven potency can induce a robust humoral immune response following vaccination. There was a comparatively higher agreement between the FAVN test and the ELISA.

The digestive tropism of SARS-CoV-2 due to the presence of the same ACE2 receptor in the digestive system as in the respiratory system raised the question of the role of fecal-oral transmission in the pandemic. The aim of this study was to explore oral infection in hamsters model. SARS-CoV-2 inoculation via the oral and intranasal routes resulted in comparable infection in hamsters. In addition to implications for human health, oral infection could have implications for potential animal reservoirs.

Understanding the transmission and persistence of zoonoses in wild reservoirs is crucial for outbreak prevention, demographic assessment, and conservation planning. Host demography, ecology, behaviour and within-host viral kinetics together underpin transmission dynamics but are rarely united within epidemiological models. Here we characterised the transmission dynamics of European bat lyssavirus 2 (EBLV-2) infection dynamics by uniting a long-term study (2010-2018) of the ecology of five greater mouse-eared bat ( Myotis myotis ) colonies in France (∼2700 marked individuals) with diagnostic evidence of virus circulation. Although no lyssavirus was detected in any of the 442 saliva samples tested, seropositivity showed synchronised peaks across colonies (0-100% annually), with the highest seroprevalence in 2015-2017, but remaining low otherwise. Fitting Bayesian compartmental epidemiological models, we found evidence that shifts in EBLV-2 prevalence were primarily driven by the gregarious behaviour of populations during the mating season and age-dependent variation in transmission. The duration of maternal immunity emerged as a key, and still empirically unknown factor, which shaped whether EBLV-2 maintenance was enzootic or required an external force of infection. Lyssavirus outbreaks in M. myotis were associated with few deaths overall and had a negligible impact on population dynamics. These findings underscore the value of integrating ecological and individual-level data with mechanistic modelling to enhance our understanding and management of zoonotic pathogens in wildlife.

The coding-complete genome sequences of hedgehog coronavirus were retrieved from rectal swabs collected in 2022 and 2023 in France. Information on this virus is crucial to understand the pathogenicity and ecology of this Betacoronavirus .

Here, we described an Alphacoronavirus coding-complete genome identified in a French brown rat. This Alphacoronavirus was detected in Rattus norvegicus intestines (colon) collected in 2022 in Marseille, France.

Only a few studies have shown that certain probiotics have beneficial effects on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this study, two strains of Bifidobacterium breve , CNCM I-5644 and CNCM I-5979, selected for their in vitro immunomodulatory properties demonstrated in a screening of 20 strains and a mixture of 4 probiotic strains selected based on its immunomodulatory and antiviral properties were evaluated in a hamster model of SARS-CoV-2 infection. Supplementation with these probiotics (7 days before plus 7 days after infection) reduced SARS-CoV-2 infection with a significantly reduced viral load in the upper respiratory tract and lungs and improved weight recovery. Probiotics also counteracted the increase in inflammatory markers and intestinal permeability. The impact of these probiotics was independent of microbiota composition and short-chain fatty acid production. Overall, these data suggest that the probiotics tested, in particular the mix containing Bifidobacterium longum LA101, Lactobacillus helveticus LA102, Lactococcus lactis LA103, and Streptococcus thermophilus LA104, can facilitate recovery from SARS-CoV-2 infection (as shown by weight regain in infected hamsters) by reducing viral load and inflammation. IMPORTANCE: Our study investigated the potential benefits of specific probiotics in fighting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (COVID-19). We tested two strains of Bifidobacterium breve selected based on their immune-boosting properties, along with a commercial mix of four probiotic strains chosen for its antiviral and immune-modulating effects. These probiotics were administered to hamsters over a week before and a week after infection. Supplementation with these probiotics significantly reduced the viral load in the upper respiratory tract and lungs, promoting recovery as demonstrated by the weight regain observed. In addition to reducing viral presence, the probiotics also helped lower inflammation and improved gut health by counteracting increased intestinal permeability. Our findings suggest that probiotics, particularly the mix of four strains, could support recovery from SARS-CoV-2 infection by reducing inflammation, viral load, and enhancing overall health.

Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, a wide range of animal species (pets, mink…) have been naturally infected with this betacoronavirus. The emergence of new variants has increased the ability of SARS-CoV-2 to infect species that were not susceptible to the “original” SARS-CoV-2, such as mice and rats. This work attempted to evaluate the role of urban rats in the SARS-CoV-2 transmission by combining surveillance studies of rat populations in urban environments, in vivo experimental inoculation of SARS-CoV-2 and comparative viral-receptor interaction in silico analyses. We studied the circulation of SARS-CoV-2 in wild Rattus norvegicus (n = 401) captured in urban areas and sewage systems of several French cities. Except for 3 inconclusive samples (2/75 from Bordeaux and 1/261 from Lyon) none of the 353 sera tested showed anti-SARS-CoV-2 antibodies by microsphere immunoassay. However, the 3 inconclusive sera samples were negative by virus neutralisation assay. No SARS-CoV-2 viral RNA was detected in all lungs collected from the 401 captured urban brown rats. In complement, four rat groups (two wild-type colonies, Rattus norvegicus and Rattus rattus, and two laboratory strains, Sprague-Dawley and Wistar) were inoculated with the SARS-CoV-2 Omicron BA.5. At 4 days post-inoculation, no infectious viral particles were detected in the lungs and upper respiratory tract (URT) while viral RNA was detected at a low level only in the URT of all groups. In addition, seroconversion was observed 14 days after inoculation in the four groups. By molecular modelling, the Omicron BA.5 receptor binding domain (RBD) had lower affinities for Rattus norvegicus and Rattus rattus ACE2 than Homo sapiens ACE2. Based on these results the SARS-CoV-2 Omicron BA.5 was unable to infect laboratory and wild type rats. In addition, Rattus norvegicus collected for this study in different areas of France were not infected with SARS-CoV-2.

Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, a wide range of animal species (pets, mink…) have been naturally infected with this betacoronavirus. The emergence of new variants has increased the ability of SARS-CoV-2 to infect species that were not susceptible to the “original” SARS-CoV-2, such as mice and rats. This work attempted to evaluate the role of urban rats in the SARS-CoV-2 transmission by combining surveillance studies of rat populations in urban environments, in vivo experimental inoculation of SARS-CoV-2 and comparative viral-receptor interaction in silico analyses. We studied the circulation of SARS-CoV-2 in wild Rattus norvegicus (n=401) captured in urban areas and sewage systems of several French cities. Except for 3 inconclusive samples (2/75 from Bordeaux and 1/261 from Lyon) none of the 353 sera tested showed anti-SARS-CoV-2 antibodies by microsphere immunoassay. However, the 3 inconclusive sera samples were negative by virus neutralisation assay. No SARS-CoV-2 viral RNA was detected in all lungs collected from the 401 captured urban brown rats. In complement, four rat groups (two wild-type colonies, Rattus norvegicus and Rattus rattus , and two laboratory strains, Sprague-Dawley and Wistar) were inoculated with the SARS-CoV-2 Omicron BA.5. At 4 days post-inoculation, no infectious viral particles were detected in the lungs and upper respiratory tract (URT) while viral RNA was detected at a low level only in the URT of all groups. In addition, seroconversion was observed 14 days after inoculation in the four groups. By molecular modelling, the Omicron BA.5 receptor binding domain (RBD) had lower affinities for Rattus norvegicus and Rattus rattus ACE2 than Homo sapiens ACE2. Based on these results the SARS-CoV-2 Omicron BA.5 was unable to infect laboratory and wild type rats. In addition, Rattus norvegicus collected for this study in different areas of France were not infected with SARS-CoV-2.

The objective of this study was to evaluate the bait preference of three selected bait types by local dogs and the induced immunogenicity of the oral rabies vaccine strain SPBN GASGAS in Morocco. The vaccine strain, combined with different bait types, has been tested in many different settings, but not yet in northern Africa. Overall, bait consumption and preference were similar in other studies using the same materials (bait type and sachet). The intestine bait had the highest acceptance rate (97.6%, 95%CI: 87.4–99.9), followed by the egg bait (83.0%, 95%CI: 69.2–92.4). Only 52% (95%CI: 37.4–66.3) of the dogs showed an interest in the fish meal bait. However, considering the successful release of the contents of the sachet (blue-dyed water) into the oral cavity, the egg bait (65.7%, 95%CI: 47.8–80.9) scored better than the intestine bait (51.7%, 95%CI: 32.5–70.6). The dogs selected for the immunogenicity study were offered the egg bait containing a sachet filled with SPBN GASGAS (3.0 mL, 10^7.5 FFU/mL) or were given the same dose by direct oral administration (d.o.a.). In addition, several dogs were vaccinated by the parenteral route (s.c.) using a commercially available inactivated rabies vaccine. Unfortunately, due to the COVID-19 pandemic and subsequent travel restrictions, it was not possible to collect blood samples directly after vaccination. The blood samples were collected pre-vaccination and on five occasions between 450 and 1088 days post vaccination. The seroconversion rate, as determined for rabies-virus-neutralizing antibodies by the FAVN test, was significantly lower than that found for binding antibodies, as determined by ELISA, for all blood samples collected post vaccination. No treatment effect (bait, d.o.a., s.c.) could be seen in the seroconversion rate. At 15 months post vaccination, 84.2% of the dogs offered vaccine bait still tested sero-positive in ELISA. Only after 3 years was a clear drop in the seroconversion rate observed in all three treatment groups. This study confirms the long-term immunogenicity of the oral rabies vaccine SPBN GASGAS in dogs under field conditions.