Infection and transmission dynamics of Turkey arthritis reovirus in different age Turkeys.

Turkey arthritis reovirus (TARV) has been established as a cause of lameness in meat type turkeys in the past decade. However, no information is available on the age susceptibility of TARV or its transmission dynamics. We conducted this study to determine the age at which turkey poults are susceptible to TARV infection and whether infected birds can horizontally transmit the virus to their non-infected pen mates (sentinels). Five groups of turkeys were orally inoculated with TARV (∼106 TCID50/ml) at 2, 7, 14, 21 and 28 days of age (DOA). Two days after each challenge, four uninfected sentinel turkeys of equal age were added to the virus-inoculated groups. At one- and two-weeks post infection, turkeys from each group, including two sentinels, were euthanized followed by necropsy. Inoculated birds in all age groups had TARV replication in the intestine and gastrocnemius tendon with no statistically significant variation at p < 0.5. Furthermore, the inoculated birds at different age groups showed consistently high gastrocnemius tendon histologic lesion scores while birds in the 28-days-old age group had numerically lower lesion scores at 14 days post inoculation (dpi). The sentinels, in turn, also showed virus replication in their intestines and tendons and histologic lesions in gastrocnemius tendons. The findings indicate that turkeys at the age of 28 days or less are susceptible to infection with TARV following oral challenge. It was also found that TARV-infected birds could transmit the infection to naïve sentinel turkeys of the same age.

Comparative pathogenesis of turkey reoviruses.

Turkey reoviruses have been implicated in multiple disease syndromes resulting in significant economic losses to the turkey industry. It has been known for decades that turkey enteric reovirus (TERV) is involved in poult enteritis complex, but turkey arthritis reovirus (TARV), the causative agent of tenosynovitis in turkeys, emerged in 2011. In 2019, we isolated reovirus from several cases of hepatitis in turkeys and tentatively named it turkey hepatitis reovirus (THRV). The comparative pathogenesis of these viruses, and correlation with their genetic make-up (if any), is not known. In this study, we inoculated nine groups of 1-week-old turkey poults with two THRV, five TARV and two TERV via oral route. A tenth group served as a negative control. A subset of birds from each group was euthanised at 3, 5, 7, 14, 21, and 28 days post-inoculation (dpi). Tissues were collected for histology and real-time RT-PCR. All nine viruses were found to be enterotropic; the virus gene copy number in the intestine reached a peak at 5 dpi followed by a sharp decline at 7 dpi. All viruses caused a significant decline in body weight gain of birds as compared to the negative control group. Both TARV and THRV strains replicated in tendons and produced histologic lesions consistent with tenosynovitis. Hepatic lesions were produced by THRV only and the virus was re-isolated from liver and spleen of inoculated birds fulfilling Koch's postulates. The results of this study should be helpful in facilitating diagnosis and designing future mitigation plans.

Characterization and Whole Genome Sequencing of Chromobacterium violaceum OUAT_2017: A Zoonotic Pathogen Found Fatal to a Wild Asiatic Elephant.

This study reports a rare fatal case of Chromobacterium violeceum OUAT_2017 strain infection in an Asiatic elephant calf in India. Necropsy revealed pus-filled nodules in liver, spleen, and lungs. Nutrient broth cultures of nodule content showed sediment of violet pigment whereas smooth, non-diffusible, violet-pigmented, homogeneous colonies appeared on nutrient agar. The organism was found to be non-haemolytic and resistant to 8 of the 24 antibiotics tested in vitro. Partial 16S rRNA gene sequence measuring 1410 bp revealed 97% homology with C. violeceum. The bacterial genome composed of 64.87% of G + C content with total size of 4,681,202 bp. The genome annotation has 42 genes responsible for multidrug antibiotic resistance with the presence of Aminoglycoside-modifying enzymes (AAC (6')) that targets streptomycin and spectinomycin. Our findings corroborated the lethal effect of C. violeceum in a new host (elephant) that enriched scientific information on epidemiological picture and whole genome sequencing as well. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01047-4.

Genomic-based characterization of Enterococcus spp.: an emerging pathogen isolated from human gut.

BACKGROUND: Enterococci are ubiquitous microorganisms having diverse ecological niches but most prominently in gastrointestinal tract of humans and animals. Production of enterocins makes them a good probiotic candidate. However, their role as probiotics has become ambiguous in the last few years because of the presence of virulence factors and antibiotic resistance genes. These virulence traits are known to be transferred genetically, which makes them opportunistic pathogens in the gastrointestinal tract leading to serious concerns about their being used as probiotics. In the present study, Enterococcusspp. isolated from the human gut were subjected to Whole-Genome Sequencing (WGS) to determine the presence of resistance and virulence genes. METHODS AND RESULTS: Four human origins Enterococcus spp. including Enterococcus faecalis, Enterococcus casseliflavus, and two Enterococcus gallinarum were isolated from human fecal samples and further cultured on blood agar. Sanger sequencing was done using Applied Biosystems 3730xl DNA Analyzer. These strains were further subjected to WGS using oxford nanopore technology MinION. Raw data were analyzed using the free online tool epi2me. The Comprehensive Antibiotic Resistance Database (CARD) and RAST (Rapid Annotation using Subsystem Technology) software were used to look for the presence of antibiotic resistance genes in these strains. Resistance determinants for clinically important antibiotics (vancomycin) and functional virulence factor genes were detected. G-view server was used for comparative genomics of all strains. CONCLUSION: The genomic sequencing of Enterococcus suggested that E. faecalis, E. casseliflavus, and E. gallinarum strains are opportunistic pathogens, having antibiotic resistance genes. All isolates had vancomycin resistance genes, which were expressed phenotypically. Genes related to bacteriocin resistance were also present in E. casseliflavus and E. gallinarum.

Novel Insight into the Effects of CpxR on Salmonella enteritidis Cells during the Chlorhexidine Treatment and Non-Stressful Growing Conditions.

The development and spread of antibiotics and biocides resistance is a significant global challenge. To find a solution for this emerging problem, the discovery of novel bacterial cellular targets and the critical pathways associated with antimicrobial resistance is needed. In the present study, we investigated the role of the two most critical envelope stress response regulators, RpoE and CpxR, on the physiology and susceptibility of growing Salmonella enterica serovar enteritidis cells using the polycationic antimicrobial agent, chlorhexidine (CHX). It was shown that deletion of the cpxR gene significantly increased the susceptibility of this organism, whereas deletion of the rpoE gene had no effect on the pathogen's susceptibility to this antiseptic. It has been shown that a lack of the CpxR regulator induces multifaceted stress responses not only in the envelope but also in the cytosol, further affecting the key biomolecules, including DNA, RNA, and proteins. We showed that alterations in cellular trafficking and most of the stress responses are associated with a dysfunctional CpxR regulator during exponential growth phase, indicating that these physiological changes are intrinsically associated with the lack of the CpxR regulator. In contrast, induction of type II toxin-antitoxin systems and decrease of abundances of enzymes and proteins associated with the recycling of muropeptides and resistance to polymixin and cationic antimicrobial peptides were specific responses of the ∆cpxR mutant to the CHX treatment. Overall, our study provides insight into the effects of CpxR on the physiology of S. Enteritidis cells during the exponential growth phase and CHX treatment, which may point to potential cellular targets for the development of an effective antimicrobial agent.

Molecular and Biological Characterization of a Cervidpoxvirus Isolated From Moose with Necrotizing Dermatitis.

Cervidpoxvirus is one of the more recently designated genera within the subfamily Chordopoxvirinae, with Deerpox virus (DPV) as the only recognized species to date. In this study, the authors describe spontaneous disease and infection in the North American moose (Alces americanus) by a novel Cervidpoxvirus, here named Moosepox virus (MPV). Three 4-month-old moose calves developed a multifocal subacute-to-chronic, necrotizing, suppurative-to-granulomatous dermatitis that affected the face and the extremities. Ultrastructurally, all stages of MPV morphogenesis-that is, crescents, spherical immature particles, mature particles, and enveloped mature virus-were observed in skin tissue. In vitro infection with MPV confirmed that its morphogenesis was similar to that of the prototype vaccinia virus. The entire coding region, including 170 putative genes of this MPV, was sequenced and annotated. The sequence length was 164,258 bp with 98.5% nucleotide identity with DPV (strain W-1170-84) based on the whole genome. The genome of the study virus was distinct from that of the reference strain (W-1170-84) in certain genes, including the CD30-like protein (83.9% nucleotide, 81.6% amino acid), the endothelin precursor (73.2% nucleotide including some indels, 51.4% amino acid), and major histocompatibility class (MHC) class I-like protein (81.0% nucleotide, 68.2% amino acid). This study provides biological characterization of a new Cervidpoxvirus attained through in vivo and in vitro ultrastructural analyses. It also demonstrates the importance of whole-genome sequencing in the molecular characterization of poxviruses identified in taxonomically related hosts.

Ìn situ inactivation of human norovirus GII.4 by cold plasma: Ethidium monoazide (EMA)-coupled RT-qPCR underestimates virus reduction and fecal material suppresses inactivation.

Cold atmospheric-gaseous plasma (CAP) is an emerging non-thermal technology for decontamination of foodborne bacterial and viral pathogens. We obtained a >5 log10 reduction in the titer (TCID50) of feline calicivirus (FCV) on stainless steel discs and Romaine lettuce leaves after 3 min wet exposure to air plasma generated by a two-dimensional array of integrated coaxial-microhollow dielectric barrier discharge (2D-AICM-DBD). However, when human norovirus (HuNoV GII.4) was treated for 5 min under the same conditions, ~2.6 log10 (>99.5%) reduction in genome copy number was observed as measured by ethidium monoazide-coupled RT-qPCR (EMA-RT-qPCR). To assess this discrepancy, we studied CAP's effect on FCV by the cell culture method and by the EMA-coupled RT-qPCR method. It was found that the molecular titration method (EMA-RT-qPCR) underestimates the level of virus reduction by CAP. Additionally, the fecal matter present in HuNoV samples partially suppressed virucidal activity of CAP. Assuming that the lower virus reduction measured by EMA-RT-qPCR method compared to cell culture method for FCV is the same as for HuNoV, we can conclude that FCV may be used as a surrogate for HuNoV to assess the virucidal effect of CAP. CAP is able to inactivate 3.5 Log10 units of HuNoV at low titers after 2 min of exposure.

Bactericidal Efficacy of a Two-Dimensional Array of Integrated, Coaxial, Microhollow, Dielectric Barrier Discharge Plasma Against Salmonella enterica Serovar Heidelberg.

We studied the efficacy of cold atmospheric-pressure plasma (CAP), generated by a two-dimensional array of integrated, coaxial, microhollow, dielectric barrier discharge plasma, against Salmonella enterica serovar Heidelberg (SH) on stainless steel, romaine lettuce, and chicken breast. Exposure of SH to CAP on a dry stainless steel surface had low bactericidal efficacy; only 2.5 log10 colony-forming units (CFUs) were inactivated after 10 min of exposure. On the other hand, the presence of moisture led to decontamination of ∼6.5 log10 CFUs after only 3 min. Although complete decontamination was not achieved on lettuce and chicken breast samples after 10 min of exposure, SH counts were reduced by ∼4.5 and 3.7 log10 CFUs, respectively. A partial suppression of bactericidal effects was observed on steel surfaces when it was coated with bovine serum albumin before spiking with bacteria and exposure to plasma, indicating that the proteinaceous nature of chicken meat may be partially responsible for lower efficacy of CAP on chicken muscles. The initial bacterial load was also found to affect the anti-SH efficacy; at high (∼6.5 log CFUs) and low (∼3.5 CFUs) initial counts, the time required for complete decontamination on stainless steel and lettuce decreased from 3 to 0.5 min and >10 to 1 min, respectively. However, the analysis of inactivation kinetics showed that effects of initial loads of contamination on the rate of bacterial inactivation were not statistically significant. This is consistent with other findings for conditions where both bacterial loads were under the multilayering threshold that might have affected the rate of killing.

Detection and genetic characterization of bovine kobuvirus from calves in Egypt.

Kobuviruses are small non-enveloped RNA viruses that probably cause diarrhea in cattle and swine. Since its discovery in 2003, few studies have addressed bovine kobuvirus (BKoV; a species of Aichivirus B) infections. BKoV has been reported in Europe, Asia, and South America, suggesting a worldwide distribution. To investigate the presence of BKoV in Egypt, 36 fecal specimens from diarrheic calves in two different Egyptian provinces (Cairo and Sharkia) were screened by RT-PCR and 24 (66.7%) were found positive for BKoV. RNA from one of the positive samples (BKoV/Egy-1/KY407744) was subjected to next-generation sequencing to determine the complete BKoV genome sequence. When compared to the only recorded BKoV genome sequence (BKoV/U-1/AB084788), the studied strain showed 94 amino acid (aa) substitutions through its entire polyprotein (2463 aa), one nucleotide (nt) insertion and one nt deletion in the 2B gene and 4-nt deletions in the UTRs (2 each). Additionally, five VP1 and seven 3D sequences were obtained from other samples by using RT-PCR and Sanger sequencing. A discrepancy in the phylogenetic topography of VP1 and 3D was observed, where the Egyptian VP1 sequences were classified as a distinct cluster within the proposed lineage 1 (genotype A), which also contained strains from the UK, Brazil, and Japan. While, the 3D sequences from Cairo were related to those of Chinese strains unlike Sharkia ones that were more closer to Korean  strains. To the best of our knowledge, this is the first detection and genomic characterization of BKoV in Egypt or indeed Africa.

Molecular detection of enteric viruses from diarrheic calves in Egypt.

Neonatal calf diarrhea (NCD) is a major cause of morbidity, mortality and economic losses in the beef and dairy industries. This study was conducted to investigate the existence of enteric viruses in two Egyptian farms with a history of recurrent diarrhea. Fecal samples were collected from 25 diarrheic calves. RNA was extracted and tested by reverse transcription polymerase chain reaction (RT-PCR) for the presence of rotavirus, norovirus, astrovirus, torovirus, coronavirus and bovine viral diarrhea virus. Overall, 76 % (19/25) of samples tested positive for one or more viruses. Rota-, noro- and astroviruses were detected in 48 %, 24 % and 32 % of tested samples, respectively. About 37 % (7/19) of positive samples had two different viruses. One-month-old calves were the group most vulnerable to infections. Based on phylogenetic analysis, bovine rotaviruses were of genotypes G6 and G10, bovine noroviruses were in GIII.2, and bovine astroviruses were in the BAstV lineage 1. Astrovirus sequences showed a high level nucleotide sequence similarity with the Brazilian BAstV sequences available in GenBank. We believe this is the first report of bovine norovirus and bovine astrovirus circulating among calves in Egypt. Further epidemiological studies are recommended to investigate their presence on a wider scale, to predict their association with NCD, and to design appropriate diagnostic and control methods.

Genomic characterization of a novel calicivirus, FHMCV-2012, from baitfish in the USA.

During regulatory sampling of fathead minnows (Pimephales promelas), a novel calicivirus was isolated from homogenates of kidney and spleen inoculated into bluegill fry (BF-2) cells. Infected cell cultures exhibiting cytopathic effects were screened by PCR-based methods for selected fish viral pathogens. Illumina HiSeq next generation sequencing of the total RNA revealed a novel calicivirus genome that showed limited protein sequence similarity to known homologs in a BLASTp search. The complete genome of this fathead minnow calicivirus (FHMCV) is 6564 nt long, encoding a polyprotein of 2114 aa in length. The complete polyprotein shared only 21% identity with Atlantic salmon calicivirus,followed by 11% to 14% identity with mammalian caliciviruses. A molecular detection assay (RT-PCR) was designed from this sequence for screening of field samples for FHMCV in the future. This virus likely represents a prototype species of a novel genus in the family Caliciviridae, tentatively named "Minovirus".

Co-circulation of paramyxo- and influenza viruses in pigeons in Egypt.

In recent years, avian influenza virus (AIV) and Newcastle disease virus (NDV) have caused large-scale outbreaks in many countries, including Egypt. The culling and vaccination strategies have failed to control both viruses in Egypt. In this study, we investigated the outbreaks of nervous manifestations and deaths in pigeons between 2013 and 2015. The H5N1 subtype of the highly pathogenic avian influenza virus and pigeon paramyxovirus-1, an antigenic variant of NDV, were found to be the cause; AIV and pigeon paramyxovirus-1 were isolated from 61.3% (19/31) and 67.8% (21/31) of tested pigeons, respectively. Co-infection with both viruses was detected in 51.6% of pigeons (16/31). The AIV sequences showed PQGEKRRKKR/GLF motif at the haemagglutinin gene cleavage site, which is typical of the highly pathogenic H5N1 subtype. The phylogenetic tree showed that the highly pathogenic avian influenza belonged to clade 2.2.1.2. The NDV sequences carried one of the three motifs, 112GKQGRL117, 112KRQKRF117 or 112RRQKRF117, at the fusion protein cleavage site and were classified as genotypes I, VI and II in NDV-class II, respectively. This indicated that different genotypes of NDV can circulate simultaneously among pigeons. Further analysis revealed the clustering of some sequences in sub-genotypes Ia and VIb.2. To the best of our knowledge, these sub-genotypes have not been previously reported from pigeons in Egypt. Our results should serve as a base for future studies on both viruses in Egypt.

Evaluation of biosecurity measures to prevent indirect transmission of porcine epidemic diarrhea virus.

BACKGROUND: The effectiveness of biosecurity methods to mitigate the transmission of porcine epidemic diarrhea virus (PEDV) via farm personnel or contaminated fomites is poorly understood. This study was undertaken to evaluate the effectiveness of biosecurity procedures directed at minimizing transmission via personnel following different biosecurity protocols using a controlled experimental setting. RESULTS: PEDV RNA was detected from rectal swabs of experimentally infected (INF) and sentinel pigs by real-time reverse transcription polymerase chain reaction (rRT-PCR). Virus shedding in INF pigs peaked at 1 day post infection (dpi) and viral RNA levels remained elevated through 19 dpi. Sentinel pigs in the low biosecurity group (LB) became PEDV positive after the first movement of study personnel from the INF group. However, rectal swabs from pigs in the medium biosecurity (MB) and high biosecurity (HB) groups were negative during the 10 consecutive days of movements and remained negative through 24 days post movement (dpm) when the first trial was terminated. Viral RNA was detected at 1 dpm through 3 dpm from the personal protective equipment (PPE) of LB personnel. In addition, at 1 dpm, 2 hair/face swabs from MB personnel were positive; however, transmission of virus was not detected. All swabs of fomite from the HB study personnel were negative. CONCLUSIONS: These results indicate that indirect PEDV transmission through contaminated PPE occurs rapidly (within 24 h) under modeled conditions. Biosecurity procedures such as changing PPE, washing exposed skin areas, or taking a shower are recommended for pig production systems and appear to be an effective option for lowering the risk of PEDV transmission between groups of pigs.

Detection and molecular characterization of astroviruses in turkeys.

This study was conducted to determine the prevalence and molecular characteristics of turkey astrovirus 1 (TAstV-1) and avian nephritis virus (ANV) in turkeys with light turkey syndrome (LTS), which is characterized by lower body weight in market-age turkeys than their standard breed character. We collected pools of fecal samples from four LTS and two non-LTS turkey flocks in Minnesota at 2, 3, 5 and 8 weeks of age. Of the 80 LTS pools tested, 16 (20.0 %) and 11 (13.8 %) were positive for TAstV-1 and ANV, respectively. For non-LTS flocks, these numbers were 8 (20.0 %) and 5 (12.5 %), respectively. The maximum number of birds was positive at five weeks of age. We also tested 130 fecal samples of poult enteritis syndrome (PES) cases submitted to the Minnesota Veterinary Diagnostic Laboratory and found 19 and 11 positive for TAstV-1 and ANV, respectively. RdRp gene sequences were determined for a total of 29 TAstV-1 and 22 ANV samples. Phylogenetic analysis of the RdRp gene revealed 92-100 % and 88-100 % nucleotide sequence identity among TAstV-1 and ANV sequences, respectively. A large number of nucleotide and amino acid substitutions were observed in LTS and PES flocks than in non-LTS flocks. One of the PES sequences grouped with ANV-like sequences detected in chickens, indicating that regular screening of birds should be continued. Further, complete genome analysis should be conducted to determine whether this virus is a novel divergent strain or a recombinant of chicken and turkey ANV-like viruses. The detection of TAstV-1 and ANV in a considerable number of non-LTS cases emphasizes the need for further studies on the transmission pattern and pathogenesis of these viruses to determine their role as pathogens of turkeys.

Virucidal effect of cold atmospheric gaseous plasma on feline calicivirus, a surrogate for human norovirus.

Minimal food-processing methods are not effective against foodborne viruses, such as human norovirus (NV). It is important, therefore, to explore novel nonthermal technologies for decontamination of foods eaten fresh, minimally processed and ready-to-eat foods, and food contact surfaces. We studied the in vitro virucidal activity of cold atmospheric gaseous plasma (CGP) against feline calicivirus (FCV), a surrogate of NV. Factors affecting the virucidal activity of CGP (a so-called radio frequency atmospheric pressure plasma jet) were the plasma generation power, the exposure time and distance, the plasma feed gas mixture, and the virus suspension medium. Exposure to 2.5-W argon (Ar) plasma caused a 5.55 log10 unit reduction in the FCV titer within 120 s. The reduction in the virus titer increased with increasing exposure time and decreasing exposure distance. Of the four plasma gas mixtures studied (Ar, Ar plus 1% O2, Ar plus 1% dry air, and Ar plus 0.27% water), Ar plus 1% O2 plasma treatment had the highest virucidal effect: more than 6.0 log10 units of the virus after 15 s of exposure. The lowest virus reduction was observed with Ar plus 0.27% water plasma treatment (5 log10 unit reduction after 120 s). The highest reduction in titer was observed when the virus was suspended in distilled water. Changes in temperature and pH and formation of H2O2 were not responsible for the virucidal effect of plasma. The oxidation of viral capsid proteins by plasma-produced reactive oxygen and nitrogen species in the solution was thought to be responsible for the virucidal effect. In conclusion, CGP exhibits virucidal activity in vitro and has the potential to combat viral contamination in foods and on food preparation surfaces.

Experimentally induced lameness in turkeys inoculated with a newly emergent turkey reovirus.

Newly emergent turkey arthritis reoviruses (TARVs) have been isolated from cases of lameness in male turkeys over 10 weeks of age. In a previous study, experimental inoculation of TARV in one-week-old turkey poults produced lymphocytic tenosynovitis at four weeks post inoculation but without causing clinical lameness. This study was undertaken to determine if TARV infection at an early age can lead to clinical lameness in birds as they age. One-week-old male turkeys were inoculated orally with a TARV (strain TARV-O'Neil) and monitored for the development of gait defects until 16 weeks of age. At 4, 8, 12 and 16 weeks of age, a subset of birds was euthanized followed by the collection of gastrocnemius tendon, digital flexor tendon, and intestines for virus detection by rRT-PCR and for histologic inflammation scoring. Clinical lameness was first displayed in TARV-infected turkeys at 8 weeks of age and ruptured gastrocnemius tendons with progressive lameness were also seen at 12-16 weeks of age. The virus was detected in gastrocnemius tendon of 4- 8- and 12-week-old turkeys but not in 16-week-old turkeys. Histologic inflammation scores of tendons at each of the four time points were significantly higher in the virus-inoculated group than in the control group (p < 0.01). Lesions began as lymphocytic tenosynovitis with mild synoviocyte hyperplasia at four weeks of age and progressed to fibrosis as the birds aged. These results demonstrate the potential of TARV to infect young turkeys and to produce subclinical tenosynovitis that becomes clinically demonstrable as the turkeys age.

Efficacy of Five Commonly Used Disinfectants Against Turkey Arthritis Reovirus.

Since late 2009, an unusual problem of reovirus-related lameness has been seen in market-age tom turkeys in the upper Midwest area of the United States. In this study, we determined the efficacy of five commonly used disinfectants (Virocid, Keno X5, Synergize, One Stroke, and Tek Trol) against turkey arthritis reoviruses (TARVs). For comparison, turkey enteric reovirus (TERV) and chicken arthritis reovirus (CARV) were also included. At their recommended concentrations, all five disinfectants were found to be effective virucidals, inactivating 99.99% of all viruses within 10 min. However, oxidizing agents and quaternary ammonium compounds + aldehyde types of disinfectants were more effective, killing the viruses in a shorter time (2-5 min) than the other types of disinfectants. These results indicate that these disinfectants can be an effective tool in the control of these viruses.

Pathogenicity of newly emergent turkey arthritis reoviruses in chickens.

Turkey arthritis reoviruses (TARVs) were isolated recently from gastrocnemius and digital flexor tendons of lame turkeys with swollen joints and tenosynovitis. These TARVs were genetically different from chicken arthritis reoviruses (CARVs) and produced gastrocnemius tenosynovitis when inoculated into turkey poults. The purpose of this study was to determine the pathogenicity of TARVs in chickens. One-week-old, specific-pathogen-free chicks were inoculated with either a TARV (TARV-MN2 or TARV-O'Neil) or CARV via oral, intratracheal, or footpad routes. At 2 and 3 weeks post inoculation (PI), a subset of chicks from each group was euthanized followed by collection of tissues for real-time RT-PCR (rRT-PCR), virus isolation, and histopathology. Chickens inoculated with CARV via intratracheal and footpad routes developed gastrocnemius lymphocytic tenosynovitis at 2 and 3 weeks PI. Both TARV-MN2 and TARV-O'Neil induced gastrocnemius lymphocytic tenosynovitis in chicks inoculated only via the footpad route at 2 and 3 weeks PI. Although there was no evidence of clinical lameness, the virus was present in leg tendons, internal organs, and intestines of all TARV-inoculated chicks regardless of route of inoculation, as indicated by rRT-PCR and virus isolation. These results indicate that TARVs do not produce gastrocnemius tenosynovitis in chicks by 3 weeks PI when administered via the most probable natural route (e.g., oral and intratracheal). Further studies are needed to determine the long term effects these viruses might play in inducing lameness in chickens.

Survival of turkey arthritis reovirus in poultry litter and drinking water.

Turkey reoviruses (TRVs) can cause arthritis, tenosynovitis, and enteric diseases in turkeys, leading to huge economic losses. The TRVs are tentatively divided into turkey arthritis reoviruses (TARVs) and turkey enteric reoviruses (TERVs) depending on the type of disease they produce. This study was conducted to determine the survival of these viruses in autoclaved and nonautoclaved poultry litter and drinking water at room temperature (approx. 25°C). Three isolates of TARV (TARV-O'Neil, TARV-MN2, and TARV-MN4) and one each of TERV (TERV-MN1) and chicken arthritis reovirus (CARV) were used in this study. The viruses were propagated and titrated on QT-35 cells. In autoclaved dechlorinated tap water, all 5 viruses were able to survive for 9 to 13 wk. In nonautoclaved water, all 5 viruses survived for at least 2 wk. In autoclaved litter, the viruses survived for 6 to 8 wk, and in nonautoclaved litter, they survived for 6 to 8 d only. The implications of these results are discussed below.

Survival of airborne MS2 bacteriophage generated from human saliva, artificial saliva, and cell culture medium.

Laboratory studies of virus aerosols have been criticized for generating airborne viruses from artificial nebulizer suspensions (e.g., cell culture media), which do not mimic the natural release of viruses (e.g., from human saliva). The objectives of this study were to determine the effect of human saliva on the infectivity and survival of airborne virus and to compare it with those of artificial saliva and cell culture medium. A stock of MS2 bacteriophage was diluted in one of three nebulizer suspensions, aerosolized, size selected (100 to 450 nm) using a differential mobility analyzer, and collected onto gelatin filters. Uranine was used as a particle tracer. The resulting particle size distribution was measured using a scanning mobility particle sizer. The amounts of infectious virus, total virus, and fluorescence in the collected samples were determined by infectivity assays, quantitative reverse transcription-PCR (RT-PCR), and spectrofluorometry, respectively. For all nebulizer suspensions, the virus content generally followed a particle volume distribution rather than a number distribution. The survival of airborne MS2 was independent of particle size but was strongly affected by the type of nebulizer suspension. Human saliva was found to be much less protective than cell culture medium (i.e., 3% tryptic soy broth) and artificial saliva. These results indicate the need for caution when extrapolating laboratory results, which often use artificial nebulizer suspensions. To better assess the risk of airborne transmission of viral diseases in real-life situations, the use of natural suspensions such as saliva or respiratory mucus is recommended.