Fecal Virus Shedding Research Articles

Fecal-Oral Transmission of COVID-19 in India

Although the spread of COVID-19 through droplets, surface contact and aerosolized transmission has been well-publicized, the fecal-oral route is yet another identified method of transmission. According to a meta-analysis by the New England Journal of Medicine, it was found that fecal viral shedding continues throughout the disease, even after nasopharyngeal tests appear negative. Moreover, gastrointestinal symptoms seem to be common for COVID-19 patients, with a prevalence of approximately 18%.[1,2] It was also found that patients with digestive symptoms experience significantly longer hospital stays.[3] As India’s number of COVID-19 cases continues to increase, concerns about fecal-oral transmission are being raised in a country that has the highest open defecation rates in the world, where approximately 620 million people defecate in the open. It is a problem that comes with severe public health consequences, including diarrhea, high child mortality, spread of diseases, malnutrition and stunting of growth.[4] Public health officials should be concerned about how this will affect India’s transmission of COVID-19. Read more.....

Prevalence of Gastrointestinal Symptoms and Fecal Viral Shedding in Patients With Coronavirus Disease 2019

Coronavirus disease 2019 (COVID-19) is a global pandemic and can involve the gastrointestinal (GI) tract, including symptoms like diarrhea and shedding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in feces. To provide a pooled estimate of GI symptoms, liver enzyme levels outside reference ranges, and fecal tests positive for SARS-CoV-2 among patients with COVID-19. An electronic literature search was performed for published (using MEDLINE/PubMed and Embase) and preprint (using bioRxiv and medRxiv) studies of interest conducted from November 1, 2019, to March 30, 2020. Search terms included "COVID-19," "SARS-Cov-2," and/or "novel coronavirus." Eligible studies were those including patients with SARS-CoV-2 infection who reported GI symptoms. Data on patients with GI symptoms (ie, diarrhea, nausea, or vomiting), liver enzyme level changes, and fecal shedding of virus were extracted. Quality of studies was examined using methodological index for nonrandomized studies. Pooled estimates (%) were reported with 95% CIs with level of heterogeneity (I2). Study and patient characteristics with pooled detection rates for diarrhea, nausea or vomiting, liver enzyme levels outside reference ranges, and SARS-CoV-2 positivity in feces tests were analyzed. Of 1484 records reviewed, 23 published and 6 preprint studies were included in the analysis, with a total of 4805 patients (mean [SD] age, 52.2 [14.8] years; 1598 [33.2%] women) with COVID-19. The pooled rates were 7.4% (95% CI, 4.3%-12.2%) of patients reporting diarrhea and 4.6% (95% CI, 2.6%-8.0%) of patients reporting nausea or vomiting. The pooled rate for aspartate aminotransferase levels outside reference ranges was 20% (95% CI, 15.3%-25.6%) of patients, and the pooled rate for alanine aminotransferase levels outside reference ranges was 14.6% (95% CI, 12.8%-16.6%) of patients. Fecal tests that were positive for SARS-CoV-2 were reported in 8 studies, and viral RNA shedding was detected in feces in 40.5% (95% CI, 27.4%-55.1%) of patients. There was high level of heterogeneity (I2 = 94%), but no statistically significant publication bias noted. These findings suggest that that 12% of patients with COVID-19 will manifest GI symptoms; however, SAR-CoV-2 shedding was observed in 40.5% of patients with confirmed SARS-CoV-2 infection. This highlights the need to better understand what measures are needed to prevent further spread of this highly contagious pathogen.

Modulation of Gut Microbiota, Short-Chain Fatty Acid Production, and Inflammatory Cytokine Expression in the Cecum of Porcine Deltacoronavirus-Infected Chicks.

Porcine deltacoronavirus (PDCoV) is a novel swine enteropathogenic coronavirus that causes watery diarrhea and induces proinflammatory cytokine responses in piglets. Our previous research showed that the specific-pathogen-free (SPF) chicks exhibited mild diarrhea and low fecal viral shedding, along with cecum lesions after PDCoV infection. Disturbances in the homeostasis of the gut microbiota have been associated with various diseases. We aimed to explore the effects of PDCoV infection on chick gut microbiota, short-chain fatty acid (SCFAs) production, and inflammatory cytokine expression in chicks, and also to investigate the relationship between gut microbiota and SCFAs or inflammatory cytokine expression of the PDCoV-infected chicks. Results obtained using 16S rRNA sequencing showed that infection with PDCoV strain HNZK-02 significantly altered the composition of chick gut microbiota, with the reduced abundance of Eisenbergiella and Anaerotruncus genera at 5 days post-inoculation (dpi) (P < 0.05), and an increased abundance of Alistipes genus at 17 dpi (P < 0.05). The production of SCFAs in the cecum of PDCoV HNZK-02–infected chicks, including acetic acid, propionic acid, and butyric acid, decreased in all cases. The expression of inflammatory cytokines (interferon-γ, tumor necrosis factor-α, and interleukin-10) was increased in the cecum tissue and serum of the PDCoV HNZK-02–infected chicks when detected by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Further analysis showed significant correlation between bacterial genera and SCFAs or inflammatory cytokines expression in cecum of the PDCoV infected chicks. These findings might provide new insight into the pathology and physiology of PDCoV in chicks.

COVID-19 and the Gastrointestinal System: What Trainees Need to Know.

COVID-19 and the Gastrointestinal System: What Trainees Need to Know.

Persistent viral shedding of SARS-CoV-2 in faeces - a rapid review.

AimIn addition to respiratory symptoms, COVID‐19 can present with gastrointestinal complaints suggesting possible faeco‐oral transmission. The primary aim of this review was to establish the incidence and timing of positive faecal samples for SARS‐CoV‐2 in patients with COVID‐19.MethodsA systematic literature review identified studies describing COVID‐19 patients tested for faecal virus. Search terms for MEDLINE included ‘clinical’, ‘faeces’, ‘gastrointestinal secretions’, ‘stool’, ‘COVID‐19’, ‘SARS‐CoV‐2’ and ‘2019‐nCoV’. Additional searches were done in the American Journal of Gastroenterology, Gastroenterology, Gut, Lancet Gastroenterology and Hepatology, the World Health Organization Database, the Centre for Evidence‐Based Medicine, New England Journal of Medicine, social media and the National Institute for Health and Care Excellence, bioRxiv and medRxiv preprints. Data were extracted concerning the type of test, number and timing of positive samples, incidence of positive faecal tests after negative nasopharyngeal swabs and evidence of viable faecal virus or faeco‐oral transmission of the virus.ResultsTwenty‐six relevant articles were identified. Combining study results demonstrated that 53.9% of those tested for faecal RNA were positive. The duration of faecal viral shedding ranged from 1 to 33 days after a negative nasopharyngeal swab with one result remaining positive 47 days after onset of symptoms. There is insufficient evidence to suggest that COVID‐19 is transmitted via faecally shed virus.ConclusionThere is a high rate of positive polymerase chain reaction tests with persistence of SARS‐CoV‐2 in faecal samples of patients with COVID‐19. Further research is needed to confirm if this virus is viable and the degree of transmission through the faeco‐oral route. This may have important implications on isolation, recommended precautions and protective equipment for interventional procedures involving the gastrointestinal tract.

The Time Sequences of Respiratory and Rectal Viral Shedding in Patients With Coronavirus Disease 2019

The Time Sequences of Respiratory and Rectal Viral Shedding in Patients With Coronavirus Disease 2019

Neonatal Management During the Coronavirus Disease (COVID-19) Outbreak: The Chinese Experience.

Novel coronavirus infection is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was named COVID-19 by the World Health Organization on January 7, 2020. In early December 2019, a number of pneumonia cases of unknown origin emerged in Wuhan, Hubei province, China. (1)(2) The disease then spread rapidly throughout China and has now become a global pandemic. As of March 23, 2020, more than 340,000 cases have been reported in more than 150 countries. Because the disease is primarily an airborne respiratory infection and is documented to have a strong human-to-human transmission, the pediatric and neonatal populations are vulnerable to this disease. However, the incidence and clinical presentations of pediatric COVID-19 infections are varied and differ from those found in adult patients. The atypical clinical presentations and 2 potential modes of transmission in neonates (ie, maternal-fetal or maternal-neonatal) have led to diagnostic and management challenges. In this perspective, we would like to share some published information from Chinese pediatric and neonatal societies about their approach to handling the 2019-2020 COVID-19 outbreak in China. Since the COVID-19 outbreak in December 2019, more than 81,000 confirmed cases have been reported in China (as of March 23, 2020). Most of these cases occurred between late January and early February 2020. The diagnosis of COVID-19 is based on the epidemiologic history of contact with an infected person, typical clinical features such as fever and respiratory distress, and a positive real-time polymerase chain reaction to the SARS-CoV-2 RNA test. The nucleic test is considered the gold standard for confirmation. As of February 8, 2020, 731 confirmed pediatric cases were reported in China, mainly from Wuhan city. (3) Relative to the total number of cases (n=34,664) reported in China, on February 8, 2020, the pediatric COVID-19 population accounted for 2.1% …

Identification and pathogenicity of a novel genotype avian hepatitis E virus from silkie fowl (gallus gallus)

Hepatitis E virus (HEV) is a public health concern because of its zoonotic potential; however, the host species spectrum and the genetic diversity of HEV in many birds are unknown. In the present study, a novel genotype avian HEV was isolated from a bird, silkie fowl, and designated CHN-GS-aHEV (GenBank No. MN562265). The genome of CHN-GS-aHEV was analyzed in comparison with other avian HEVs’ and the pathogenicity in silkie fowl was characterized. The results show that the CHN-GS-aHEV shares about 81 % identity with known avian HEV in chickens, ORF3 shares the highest identity (85.1 %–88.0 %) at the nucleotide level, while ORF2 shares the highest identity (96.5 %–98.0 %) at the amino acid level, indicating that the CHN-GS-aHEV belongs to a new genotype avian HEV. The pathogenicity study showed that silkie fowl experimentally infected with the CHN-GS-aHEV demonstrated seroconversion, viremia, fecal virus shedding, liver lesions, and increased ALT level. Furthermore, ultrastructural changes in hepatocyte cells by transmission electron microscopy were characterized by the loss of mitochondrial cristae and swollen mitochondria and endoplasmic reticulum in the infected birds, suggesting that these two organelles may play a significant role in HEV replication. Overall, this study reports the complete genome characterization of a novel avian HEV and successful experimental infection in silkie fowl, and may be serving as a prominent indicator for additional avian HEV detection in other species.

Synthetic Peptides Containing Three Neutralizing Epitopes of Genotype 4 Swine Hepatitis E Virus ORF2 induced Protection against Swine HEV Infection in Rabbit.

Genotype 4 hepatitis E virus (HEV) is a zoonotic pathogen transmitted to humans through food and water. Previously, three genotype 4 swine HEV ORF2 peptides (407EPTV410, 410VKLYTS415, and 458PSRPF462) were identified as epitopes of virus-neutralizing monoclonal antibodies that partially blocked rabbit infection with swine HEV. Here, individual and tandem fused peptides were synthesized, conjugated to keyhole limpet hemocyanin (KLH), then evaluated for immunoprotection of rabbits against swine HEV infection. Forty New Zealand White rabbits were randomly assigned to eight groups; groups 1 thru 5 received three immunizations with EPTV-KLH, VKLYTS-KLH, PSRPF-KLH, EPTVKLYTS-KLH, or EPTVKLYTSPSRPF-KLH, respectively; group 6 received truncated swine HEV ORF2 protein (sp239), and group 7 received phosphate-buffered saline. After an intravenous swine HEV challenge, all group 7 rabbits exhibited viremia and fecal virus shedding by 2–4 weeks post challenge (wpc), seroconversion by 4–9 wpc, elevated alanine aminotransferase (ALT) at 2 wpc, and severe liver lymphocytic venous periphlebitis. Only 1–2 rabbits/group in groups 1–4 exhibited delayed viremia, fecal shedding, seroconversion, increased ALT levels, and slight liver lymphocytic venous periphlebitis; groups 5–6 showed no pathogenic effects. Collectively, these results demonstrate that immunization with a polypeptide containing three genotype 4 HEV ORF2 neutralizing epitopes completely protected rabbits against swine HEV infection.

Prolonged viral shedding in feces of pediatric patients with coronavirus disease 2019.

ObjectiveTo determine the dynamic changes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in respiratory and fecal specimens in children with coronavirus disease 2019 (COVID-19).MethodsFrom January 17, 2020 to February 23, 2020, three paediatric cases of COVID-19 were reported in Qingdao, Shandong Province, China. Epidemiological, clinical, laboratory, and radiological characteristics and treatment data were collected. Patients were followed up to March 10, 2020, and dynamic profiles of nucleic acid testing results in throat swabs and fecal specimens were closely monitored.ResultsClearance of SARS-CoV-2 in respiratory tract occurred within two weeks after abatement of fever, whereas viral RNA remained detectable in stools of pediatric patients for longer than 4 weeks. Two children had fecal SARS-CoV-2 undetectable 20 days after throat swabs showing negative, while that of another child lagged behind for 8 days.ConclusionsSARS-CoV-2 may exist in children's gastrointestinal tract for a longer time than respiratory system. Persistent shedding of SARS-CoV-2 in stools of infected children raises the possibility that the virus might be transmitted through contaminated fomites. Massive efforts should be made at all levels to prevent spreading of the infection among children after reopening of kindergartens and schools.

Safety and immunogenicity of an experimental live combination vaccine against enterovirus 71 and coxsackievirus A16 in rhesus monkeys

ABSTRACT Enterovirus 71 (EV-A71) and Coxsackievirus A16 (CV-A16) are the two most common pathogens causing hand, foot, and mouth disease (HFMD). Previously, we obtained one candidate live attenuated strain each for EV-A71 and CV-A16; here, we evaluated the safety and immunogenicity of a combinedlive vaccine against EV-A71 and CV-A16 generated from these two candidate strains. Rhesus monkeys were intramuscularly treated with a live combinationvaccine against both EV-A71 and CV-A16 or with either vaccine alone. No fever or atypical clinical signs were observed in any animals. Monkeys vaccinated with the combinationlive vaccine presented no notable pathological changes in the brain, spinal cord, lung, and liver; in contrast, these regions showed inflammatory cell infiltration in monkeys treated with EV-A71 alone or CV-A16 alone. Weak viremia was detected in plasma after inoculation with the combinationvaccine; however, the duration of viral shedding in feces was increased. Biochemical studies revealed a slight increase in aspartate aminotransferase levels in monkeys inoculated with the live combination vaccine; however, histopathological findings did not attribute this change to liver damage. We also found that the live combinationvaccine induced a dual humoral immune response. Cytokine analysis indicated that the combined EV-A71/CV-A16 vaccine significantly down-regulated interleukin-8 production. Here, we have demonstrated that the live attenuated EV-A71/CV-A16 vaccine was safe and could trigger a dual specific immune response. However, its immune protection efficacy requires further investigation.

Strain-Specific Probiotic Properties of Bifidobacteria and Lactobacilli for the Prevention of Diarrhea Caused by Rotavirus in a Preclinical Model.

Probiotic supplementation with different lactobacilli and bifidobacterial strains has demonstrated beneficial effects in infectious diarrhea caused by rotavirus (RV) in young children. Preclinical models of RV infection might be a good strategy to screen for the efficacy of new probiotic strains or to test their comparative efficacy. Neonatal Lewis rats were supplemented with Bifidobacterium breve M-16V, Lactobacillus acidophilus NCFM, Lactobacillus helveticus R0052, or Lactobacillus salivarius PS2 from days 2–14 of life. On day five, animals received RV SA-11 orally. Fecal samples were collected daily, weighed, and scored for the calculation of severity and incidence of diarrhea. In addition, fecal pH and fecal viral shedding were measured. Animals were sacrificed at the end of the study and their blood was obtained for the quantification of RV-specific immunoglobulins. RV infection was induced in ~90% of the animals. All probiotics caused a reduction of several clinical variables of severity and incidence of diarrhea, except L. salivarius PS2. L. acidophilus NCFM, B. breve M-16V, and L. helveticus R0052 seemed to be very effective probiotic strains. In addition, all Lactobacillus strains reduced the viral elimination one day post-inoculation. No differences were detected in the specific anti-RV humoral response. The present study highlights the strain-specific effects of probiotics and identifies promising probiotics for use in ameliorating and preventing RV-induced diarrhea in children, for example by including them in infant formulas.

Protection of chickens against hepatitis-hydropericardium syndrome and Newcastle disease with a recombinant Newcastle disease virus vaccine expressing the fowl adenovirus serotype 4 fiber-2 protein

Newcastle disease (ND) is one of the most important and devastating avian diseases with considerable threat to the global poultry industry. Hepatitis-hydropericardium syndrome (HHS), caused by virulent fowl adenovirus serotype 4 (FAdV-4), is another highly infectious disease in chickens with severe economic impact. The effective way to combat ND and HHS is by vaccinating the poultry. In the present study, a recombinant NDV LaSota vaccine strain expressing full length fiber-2 gene of FAdV-4 (rLaSota-fiber2) was generated using reverse genetics. The FAdV-4 fiber-2 protein was expressed as a soluble form rather than NDV membrane-anchored form. The rLaSota-fiber2 was genetically stable, and it showed growth patterns in embryonated eggs comparable to that of parental rLaSota virus. Since our unpublished data demonstrated that delivery of live rLaSota-fiber2 in drinking water or ocular delivery of the vaccine didn’t produce protection against hypervirulent FAdV-4 challenge, even though the vaccine provide full protection against NDV challenge, the efficacy of the rLaSota-fiber2 was evaluated by delivering the vaccine intramuscularly in this study. Single-dose intramuscular vaccination of 2-week-old SPF White Leghorn chicks with the live or inactivated rLaSota-fiber2 provided complete protection against virulent NDV challenge. However, single-dose intramuscular vaccination with the live rLaSota-fiber2 vaccine provided better protection against virulent FAdV-4 challenge and significantly reduced faecal viral shedding comparing to the inactivated vaccine. These results indicate that the NDV-vectored FAdV-4 vaccine is a promising bivalent vaccine candidate to control both HHS and ND.

Parenterally Administered P24-VP8* Nanoparticle Vaccine Conferred Strong Protection against Rotavirus Diarrhea and Virus Shedding in Gnotobiotic Pigs.

Current live rotavirus vaccines are costly with increased risk of intussusception due to vaccine replication in the gut of vaccinated children. New vaccines with improved safety and cost-effectiveness are needed. In this study, we assessed the immunogenicity and protective efficacy of a novel P24-VP8* nanoparticle vaccine using the gnotobiotic (Gn) pig model of human rotavirus infection and disease. Three doses of P24-VP8* (200 μg/dose) intramuscular vaccine with Al(OH)3 adjuvant (600 μg) conferred significant protection against infection and diarrhea after challenge with virulent Wa strain rotavirus. This was indicated by the significant reduction in the mean duration of diarrhea, virus shedding in feces, and significantly lower fecal cumulative consistency scores in post-challenge day (PCD) 1–7 among vaccinated pigs compared to the mock immunized controls. The P24-VP8* vaccine was highly immunogenic in Gn pigs. It induced strong VP8*-specific serum IgG and Wa-specific virus-neutralizing antibody responses from post-inoculation day 21 to PCD 7, but did not induce serum or intestinal IgA antibody responses or a strong effector T cell response, which are consistent with the immunization route, the adjuvant used, and the nature of the non-replicating vaccine. The findings are highly translatable and thus will facilitate clinical trials of the P24-VP8* nanoparticle vaccine.

Attenuation and characterization of porcine enteric alphacoronavirus strain GDS04 via serial cell passage

Porcine enteric alphacoronavirus (PEAV) is a newly identified swine enteropathogenic coronavirus that causes watery diarrhea in newborn piglets. In this study, an original, highly virulent PEAV strain GDS04 was serially passaged in Vero cells. The virus titers and sizes of syncytia increased gradually with the cell passages. Newborn piglets were orally inoculated with PEAV P15, P67 and P100. Compared with P15 and P67, P100 resulted in only mild clinical signs and intestinal lesions in piglets. The virus shedding in feces and viral antigens in intestinal tract were markedly reduced in P100-inoculated piglets. Importantly, all P100-inoculated newborn piglets survived, indicating that P100 was an attenuated variant. Sequence analysis revealed that the virulent strain GDS04 had four, one, six and eleven amino acid differences in membrane, nucleocapsid, spike and ORF1ab proteins, respectively, from P100. Furthermore, more differences in the predicted three-dimensional structure of S protein between GDS04 and P100 were observed, indicating that these differences might be associated with the pathogenicity of PEAV. Collectively, our research successfully prepared a PEAV attenuated variant which might serve as a live attenuated vaccine candidate against PEAV infection.

A Minimally Replicative Vaccine Protects Vaccinated Piglets Against Challenge With the Porcine Epidemic Diarrhea Virus.

Porcine epidemic diarrhea virus (PEDV), is an economically important enteric coronavirus, with over a 90% mortality rate in neonatal piglets. The virus emerged in the US in 2013, resulting in severe production losses. Effective vaccine development against PEDV is a challenge. Inactivated vaccines are of questionable efficacy. Attenuated vaccines, while more effective, require a relatively long lead development time, are associated with safety concerns and are also unable to prevent new field outbreaks. To combine the safety and efficacy advantages of inactivated and attenuated PEDV vaccines, respectively, in this study, we tested the hypothesis that subjecting PEDV virions to heat treatment at 44°C for 10 min to reversibly unfold structural proteins, followed by exposure to RNAse to fragment the genome, would result in a vaccine preparation with intact viral structure/antigenicity but highly diminished replicative abilities. We expected the vaccine to be both safe and effective in a piglet challenge model. Following the heat and RNAse treatment, PEDV virions had an intact electron microscopic ultrastructure and were amplified only in the 3rd passage in Vero cells, indicating that diminished replication was achieved in vitro. Strong PEDV spike-protein specific and virus neutralizing antibody responses were elicited in vaccinated piglets. Upon challenge, all vaccinated pigs were protected against fecal viral shedding and intestinal pathology, while the unvaccinated controls were not. The vaccine virus was not detected in the fecal matter of vaccinated pigs prior to challenge; nor did they develop intestinal lesions. Thus, the described approach has significant promise in improving current approaches for PEDV immunization.

Efficacy of a commercial porcine epidemic diarrhea virus vaccine at reducing duration of viral shedding in gilts

Objective: To evaluate if the use of a commercially available killed porcine epidemic diarrhea virus (PEDV) vaccine shortens the duration of PEDV shedding in replacement gilts. Materials and methods: Four treatment groups composed of 20 females were utilized for this study. Gilts in the CONTROL group had no previous exposure to PEDV, the nonvaccinated (NV) group had been previously exposed, and the PRE and POST groups received two doses of a commercial, killed PEDV vaccine either prior to or following a challenge with PEDV, respectively. Individual fecal samples were collected weekly and tested by real-time reverse transcription-polymerase chain reaction (rRT-PCR) for virus detection. Results: Previous exposure to PEDV was found to shorten the time that virus can be detected in the feces compared to fecal samples of naïve animals (P &lt; .001). Vaccination, either prior to or following the challenge, was not found to shorten the duration of PEDV shedding in feces. Implications: These results showed that vaccination of gilts, either prior to the challenge or afterwards, with a killed commerical PEDV vaccine did not shorten the period that virus was detectable in the feces by rRT-PCR suggesting that viral shedding in feces was not influenced by administration of a killed commercial vaccine. While previous infection with virulent PEDV did not prevent re-infection, it did have a significant effect on the amount of time virus was detected following a subsequent exposure.

Evaluation of the protective effects of a nanogel-based vaccine against rabbit hepatitis E virus

Infection with hepatitis E virus (HEV) has raised serious public health concerns worldwide. In this study, a nanogel-based vaccine encapsulating the capsid protein of rabbit HEV was developed and its protective efficacy was compared with a subunit vaccine. A total of 23 rabbits were divided into 5 groups: (1) negative control (n = 4), (2) positive control (n = 4), (3) nanogel control (n = 5), (4) nanogel vaccine (n = 5), and (5) subunit vaccine (n = 5). Rabbits were vaccinated two times, at weeks 0 and 1, with nanogel and subunit vaccines, respectively, and challenged with rabbit HEV at week 4. By week 11, rabbits vaccinated with the nanogel vaccine produced higher antibodies than those vaccinated with the subunit vaccine. Fecal viral shedding and viremia were identified in rabbits of the positive and nanogel control groups at weeks 6–10. However, there was no viral shedding and viremia in rabbits immunized with both the nanogel and subunit vaccines. Alanine aminotransferase and aspartate aminotransferase levels were not elevated in any rabbit. However, histopathological examination revealed much less hepatic inflammation in rabbits of the nanogel vaccine group compared to the positive and nanogel control groups. Significant increases in IL-12 and IFN–γlevels were identified from rabbits immunized with the nanogel vaccine. Collectively, these results indicate that the newly developed nanogel vaccine induced sufficient immunity leading to complete protection from HEV infection in rabbits. Application of this vaccine should be considered as a preventive measure against HEV infection in other animal species and humans.

CD8+ lymphocytes but not B lymphocytes are required for protection against chronic hepatitis E virus infection in chickens.

Hepatitis E is an important global disease, causing outbreaks of acute hepatitis in many developing countries and sporadic cases in industrialized countries. Hepatitis E virus (HEV) infection typically causes self-limiting acute hepatitis but can also progress to chronic disease in immunocompromised individuals. The immune response necessary for the prevention of chronic infection is T cell-dependent; however, the arm of cellular immunity responsible for this protection is not currently known. To investigate the contribution of humoral immunity in control of HEV infection and prevention of chronicity, we experimentally infected 20 wild-type (WT) and 18 immunoglobulin knockout (JH-KO) chickens with a chicken strain of HEV (avian HEV). Four weeks postinfection (wpi) with avian HEV, JH-KO chickens were unable to elicit anti-HEV antibody but had statistically significantly lower liver lesion scores than the WT chickens. At 16 wpi, viral RNA in fecal material and liver, and severe liver lesions were undetectable in both groups. To determine the role of cytotoxic lymphocytes in the prevention of chronicity, we infected 20 WT and 20 cyclosporine and CD8+ antibody-treated chickens with the same strain of avian HEV. The CD8 + lymphocyte-depleted, HEV-infected chickens had higher incidences of prolonged fecal viral shedding and statistically significantly higher liver lesion scores than the untreated, HEV-infected birds at 16 wpi. The results indicate that CD8 + lymphocytes are required for viral clearance and reduction of liver lesions in HEV infection while antibodies are not necessary for viral clearance but may contribute to the development of liver lesions in acute HEV infection.

Susceptibility of Chickens to Porcine Deltacoronavirus Infection

Porcine deltacoronavirus (PDCoV) is a novel swine enteropathogenic coronavirus with worldwide distribution. PDCoV belongs to the Deltacoronavirus (DCoV) genus, which mainly includes avian coronaviruses (CoVs). PDCoV has the potential to infect human and chicken cells in vitro, and also has limited infectivity in calves. However, the origin of PDCoV in pigs, the host range, and cross-species infection of PDCoV still remain unclear. To determine whether PDCoV really has the ability to infect chickens in vivo, the three lines of chicken embryos and specific pathogen free (SPF) chickens were inoculated with PDCoV HNZK-02 strain to investigate PDCoV infection in the current study. Our results indicated that PDCoV can infect chicken embryos and could be continuously passaged on them. Furthermore, we observed that PDCoV-inoculated chickens showed mild diarrhea symptoms and low fecal viral RNA shedding. PDCoV RNA could also be detected in multiple organs (lung, kidney, jejunum, cecum, and rectum) and intestinal contents of PDCoV-inoculated chickens until 17 day post-inoculation by real-time quantitative PCR (qRT-PCR). A histology analysis indicated that PDCoV caused mild lesions in the lung, kidney, and intestinal tissues. These results prove the susceptibility of chickens to PDCoV infection, which might provide more insight about the cross-species transmission of PDCoV.