Establishment of Intestinal Organoid from Rousettus leschenaultii and the Susceptibility to Bat-Associated Viruses, SARS-CoV-2 and Pteropine Orthoreovirus

Various pathogens, such as Ebola virus, Marburg virus, Nipah virus, Hendra virus, Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2, are threatening human health worldwide. The natural hosts of these pathogens are thought to be bats. The rousette bat, a megabat, is thought to be a natural reservoir of filoviruses, including Ebola and Marburg viruses. Additionally, the rousette bat showed a transient infection in the experimental inoculation of SARS-CoV-2. In the current study, we established and characterized intestinal organoids from Leschenault’s rousette, Rousettus leschenaultii. The established organoids successfully recapitulated the characteristics of intestinal epithelial structure and morphology, and the appropriate supplements necessary for long-term stable culture were identified. The organoid showed susceptibility to Pteropine orthoreovirus (PRV) but not to SARS-CoV-2 in experimental inoculation. This is the first report of the establishment of an expandable organoid culture system of the rousette bat intestinal organoid and its sensitivity to bat-associated viruses, PRV and SARS-CoV-2. This organoid is a useful tool for the elucidation of tolerance mechanisms of the emerging rousette bat-associated viruses such as Ebola and Marburg virus.

Inoculating against the spread of Islamophobic and radical-Islamist disinformation

We report the results of a preregistered study that tested the effectiveness of inoculating participants against Islamophobic and radical-Islamist disinformation. Participants in the experimental (inoculation) condition watched a video that explained common rhetorical markers of radical-Islamist and Islamophobic disinformation that had been identified in an analysis of YouTube content. The information was presented in a neutral context not involving Islam and focused on analysis of the misleading argumentation. The control group watched a video about an unrelated topic. Participants were then exposed to target videos with “gateway” content that constituted an entry point to potential Islamist or Islamophobic radicalization. Both videos contained numerous items of disinformation. Participants then answered a variety of questions such as how likely they were to share the video, their level of agreement, and their perceived accuracy of the video. Participants who had received the inoculation displayed less agreement with the video content, perceived the video as less reliable, and were less likely to share it in comparison with participants in the control group. The study provides support for the use of argument-based inoculation in combatting extremist messages.

Molecular Characterization of Velogenic Avian Avulavirus Type 1 Isolated from Apparently Healthy Emu Birds: Implications to Viral Maintenance and Spread

Background: Newcastle disease caused by Avian avulavirus type 1 (AAvV-1) is one of the dreadful diseases affecting poultry and other avian species. Wild birds and several domestic birds are recognized as reservoirs of AAvV-1 and probably contribute to the epidemiology of ND in the domesticated poultry. Hence, efforts have been made to understand the virulence and genetic nature of AAvV-1 isolates obtained from apparently healthy Emu birds.Methods: This study details characterization of a velogenic Emu/5 AAvV-1 isolate obtained from an asymptomatic emu flock. Full- length fusion gene was amplified and subsequent phylogenetic analysis was performed. Experimental inoculation of 3-week old chicken with the isolate resulted in virulent ND. Expression of cytokine mRNA levels in spleen of infected chicken at different time points correlated well with the clinical picture, gross and histopathological lesions.Result: To our knowledge this is the first evidence for the role of apparently healthy emu bird acting as a reservoir of velogenic AAvV-1 of subgenotype XIII 2.2 which proved to be highly virulent to chicken. This study further highlights the role of reservoir birds in AAvV-1 transmission and the need for adopting most realistic strategies in counteracting the disease.

Putative Novel Serotypes ‘33’ and ‘35’ in Clinically Healthy Small Ruminants in Mongolia Expand the Group of Atypical BTV

Between 2015 and 2018, we identified the presence of three so-far-unknown Bluetongue virus (BTV) strains (BTV-MNG1/2018, BTV-MNG2/2016, and BTV-MNG3/2016) circulating in clinical healthy sheep and goats in Mongolia. Virus isolation from EDTA blood samples of BTV-MNG1/2018 and BTV-MNG3/2016 was successful on the mammalian cell line BSR using blood collected from surveillance. After experimental inoculation of goats with BTV-MNG2/2016 positive blood as inoculum, we observed viraemia in one goat and with the EDTA blood of the experimental inoculation, the propagation of BTV-MNG2/2016 in cell culture was successful on mammalian cell line BSR as well. However, virus isolation experiments for BTV-MNG2/2016 on KC cells were unsuccessful. Furthermore, we generated the complete coding sequence of all three novel Mongolian strains. For atypical BTV, serotyping via the traditional serum neutralization assay is not trivial. We therefore sorted the ‘putative novel atypical serotypes’ according to their segment-2 sequence identities and their time point of sampling. Hence, the BTV-MNG1/2018 isolate forms the ‘putative novel atypical serotype’ 33, the BTV-MNG3/2016 the ‘putative novel atypical serotype’ 35, whereas the BTV-MNG2/2016 strain belongs to the same putative novel atypical serotype ‘30’ as BTV-XJ1407 from China.

Experimental SARS-CoV-2 infection of bank voles - general susceptibility but lack of direct transmission

After experimental inoculation, SARS-CoV-2 infection was proven for bank voles by seroconversion within eight days and detection of viral RNA in nasal tissue for up to 21 days. However, transmission to contact animals was not detected. Therefore, bank voles are unlikely to establish effective SARS-CoV-2 transmission cycles in nature.Article Summary LineBank voles show low-level viral replication and seroconversion upon infection with SARS-CoV-2, but lack transmission to contact animals.

Sheep and Cattle Are Not Susceptible to Experimental Inoculation with Hazara Orthonairovirus, a Tick-Borne Arbovirus Closely Related to CCHFV

Hazara orthonairovirus (HAZV) is a tick-borne arbovirus closely related to Crimean–Congo hemorrhagic fever orthonairovirus (CCHFV). Whereas CCHFV is a biosafety level (BSL) 4 agent, HAZV is classified as BSL 2, as it is not known to cause any disease in humans. Belonging to the same serogroup as CCHFV, HAZV might act as a model which can provide a better understanding of this important zoonosis. Furthermore, the serological relatedness may cause diagnostic problems if antibodies against HAZV interfere with current CCHFV serological assays. Therefore, sheep and cattle—important natural hosts for CCHFV—were experimentally infected with HAZV to prove their susceptibility and evaluate potential antibody cross-reactivities. According to this study, neither sheep nor cattle are susceptible to experimental HAZV infections. Consequently, the HAZV infection in ruminants is clearly distinct from CCHFV infections. Sera of immunized animals weakly cross-reacted between HAZV and CCHFV in immunofluorescence and immunoblot assays, but not in commercial CCHFV ELISAs commonly used for field studies.

Pseudocapillaria tomentosa, Mycoplasma spp., and intestinal lesions in experimentally infected zebrafish Danio rerio

Intestinal neoplasms and preneoplastic lesions are common in zebrafish research facilities. Previous studies have demonstrated that the neoplasms are caused by a transmissible agent, and two candidate agents have been implicated: a Mycoplasma sp. related to M. penetrans and the intestinal parasitic nematode, Pseudocapillaria tomentosa, and both agents are common in zebrafish facilities. To elucidate the role of these two agents in the occurrence and severity of the neoplasm and other intestinal lesions, we conducted two experimental inoculation studies. Exposed fish were examined at various time points over an 8 mo. period for intestinal histpathologic changes and the burden of Mycoplasma and nematodes. Fish exposed to a Mycoplasma isolate from zebrafish were associated with preneoplastic lesions. Fish exposed to the nematode alone or with the Mycoplasma isolate developed severe lesions and neoplasms. Both inflammation and neoplasm scores were associated with an increase in Mycoplasma burden. These results support the conclusions that P. tomentosa is a strong promoter of intestinal neoplasms in zebrafish, and that Mycoplasma alone can also cause intestinal lesions and accelerate cancer development in the context of nematode infection.