Acute Enteric Disease Research Articles

Intestinal microbial communities associated with acute enteric infections and disease recovery.

BackgroundThe intestinal microbiome represents a complex network of microbes that are important for human health and preventing pathogen invasion. Studies that examine differences in intestinal microbial communities across individuals with and without enteric infections are useful for identifying microbes that support or impede intestinal health.Results16S rRNA gene sequencing was conducted on stool DNA from patients with enteric infections (n = 200) and 75 healthy family members to identify differences in intestinal community composition. Stools from 13 patients were also examined post-infection to better understand how intestinal communities recover. Patient communities had lower species richness, evenness, and diversity versus uninfected communities, while principle coordinate analysis demonstrated close clustering of uninfected communities, but not the patient communities, irrespective of age, gender, and race. Differences in community composition between patients and family members were mostly due to variation in the abundance of phyla Proteobacteria, Bacteroidetes, and Firmicutes. Patient communities had significantly more Proteobacteria representing genus Escherichia relative to uninfected communities, which were dominated by Bacteroides. Intestinal communities from patients with bloody diarrhea clustered together in the neighbor-joining phylogeny, while communities from 13 patients’ post-infection had a significant increase in Bacteroidetes and Firmicutes and clustered together with uninfected communities.ConclusionsThese data demonstrate that the intestinal communities in patients with enteric bacterial infections get altered in similar ways. Furthermore, preventing an increase in Escherichia abundance may be an important consideration for future prevention strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-015-0109-2) contains supplementary material, which is available to authorized users.

An insulated isothermal PCR method on a field-deployable device for rapid and sensitive detection of canine parvovirus type 2 at points of need

Canine parvovirus type 2 (CPV-2), including subtypes 2a, 2b and 2c, causes an acute enteric disease in both domestic and wild animals. Rapid and sensitive diagnosis aids effective disease management at points of need (PON). A commercially available, field-deployable and user-friendly system, designed with insulated isothermal PCR (iiPCR) technology, displays excellent sensitivity and specificity for nucleic acid detection. An iiPCR method was developed for on-site detection of all circulating CPV-2 strains. Limit of detection was determined using plasmid DNA. CPV-2a, 2b and 2c strains, a feline panleukopenia virus (FPV) strain, and nine canine pathogens were tested to evaluate assay specificity. Reaction sensitivity and performance were compared with an in-house real-time PCR using serial dilutions of a CPV-2b strain and 100 canine fecal clinical samples collected from 2010 to 2014, respectively. The 95% limit of detection of the iiPCR method was 13 copies of standard DNA and detection limits for CPV-2b DNA were equivalent for iiPCR and real-time PCR. The iiPCR reaction detected CPV-2a, 2b and 2c and FPV. Non-targeted pathogens were not detected. Test results of real-time PCR and iiPCR from 99 fecal samples agreed with each other, while one real-time PCR-positive sample tested negative by iiPCR. Therefore, excellent agreement (k=0.98) with sensitivity of 98.41% and specificity of 100% in detecting CPV-2 in feces was found between the two methods. In conclusion, the iiPCR system has potential to serve as a useful tool for rapid and accurate PON, molecular detection of CPV-2.

Molecular characterization and phylogenetic analysis of porcine epidemic diarrhea viruses associated with outbreaks of severe diarrhea in piglets in Jiangxi, China 2013.

Porcine epidemic diarrhea (PED), caused by porcine epidemic diarrhea virus (PEDV), is a highly contagious, acute enteric viral disease of swine characterized by vomiting, watery diarrhea, dehydration and death. To identify and characterize the field PEDVs associated with the outbreaks of severe diarrhea in piglets in Jiangxi, 2013, the complete genome sequences of two representative strains of PEDV, designated CH/JX-1/2013 and CH/JX-2/2013, were determined and analyzed. The genome sequences of both emergent Jiangxi PEDV strains, CH/JX-1/2013 and CH/JX-2/2013, were 28,038 nucleotides in length excluding 3’ poly (A) tail. Compared to the PEDV CV777 strain, CH/JX-1/2013 and CH/JX-2/2013 had some unique genetic characteristics in the proximal region of the 5´-UTRs. Phylogenetic analysis of the complete genomes and the structural proteins revealed that CH/JX-1/2013 and CH/JX-2/2013 had a close relationship with post-2010 Chinese PEDV strains and US strains identified in 2013. The nucleotide identity between the two Jiangxi strains (CH/JX-1/2013 and CH/JX-2/2013) and 30 strains of PEDV identified ante-2010 and post-2010 ranged from 96.3–97.0% and 97.3–99.7%, respectively. Multiple nucleotide and deduced amino acid mutations were observed in the ORF1a/b, S, ORF3, E, M and N genes among the current field PEDV strains when compared to the CV777 strain. Some of the mutations altered the amino acid charge and hydrophilicity, and notably, there was an amino acid substitution in the middle of one neutralizing epitope (L1371I) of the S gene of both CH/JX-1/2013 and CH/JX-2/2013. Taken together, the accumulated genetic variations of the current field PEDV strains might have led to antigenic changes of the viruses, which might confer the less effectiveness or failure of the CV777-based vaccines currently being widely used in Jiangxi, China.

Genotyping and pathobiologic characterization of canine parvovirus circulating in Nanjing, China.

BackgroundCanine parvovirus (CPV) is an important pathogen that causes acute enteric disease in dogs. It has mutated and spread throughout the world in dog populations. We provide an update on the molecular characterization of CPV that circulated in Nanjing, a provincial capital in China between 2009 and 2012.ResultsSeventy rectal swab samples were collected from the dogs diagnosed with CPV infection in 8 animal hospitals of Nanjing. Sequence analysis of VP2 genes of 31 samples revealed that 29 viral strains belonged to CPV-2a subtype, while other two strains were classified into CPV-2b. To investigate the pathogenicity of the prevalent virus, we isolated CPV-2a and performed the animal experiment. Nine beagles were inoculated with 105.86 of 50% tissue culture infectious doses (TCID50) of the virus. All the experimentally infected beagles exhibited mild to moderate mucoid or watery diarrhea on day 4 post-infection (p.i.). On day 9 p.i., characteristic histopathological lesions were clearly observed in multiple organs of infected dogs, including liver, spleen, kidney, brain and all segments of the small and large intestines, while viral DNA and antigen staining could be detected in the sampled tissues. It is notable that canine parvovirus was isolated in one from two brain samples processed.ConclusionOur results indicated that CPV-2a is the predominant subtype in Nanjing of China. And this virus caused extensive lesions in a variety of tissues, including the brain.

An updated TaqMan real-time PCR for canine and feline parvoviruses

Canine parvovirus type 2 (CPV-2) emerged in late 1970s from the feline panleukopenia virus (FPLV) and developed, since then, into novel genetic and antigenic variants (CPV-2a, -2b and -2c). Canine and feline parvoviruses cause an acute enteric disease in their hosts, with high level of viral shedding. In this study, a quantitative TaqMan PCR for detection and quantitation of canine and feline parvoviruses in serum and fecal samples was developed. The primers were designed based upon the entire GenBank content for CPV and FPLV. A standard curve was generated, and validation tests were performed using 10-fold serial dilutions of CPV-2 virus in CPV/FPLV-negative feces and CPV/FPLV-negative serum samples. As a result, the 100% detection limit of the PCR was 18 copies of the viral genome per μl of serum and fecal sample. All canine parvovirus types as well as FPLV were detected. In conclusion, the real-time PCR represents an upgraded and useful tool to identify and quantify canine and feline parvoviruses in different sample matrices.

Years of potential life lost for six major enteric pathogens, Germany, 2004–2008

In industrialized countries, acute infectious enteric diseases are usually mild, but they can also cause death. They do so, however, at different ages. Using 2004-2008 German notification data, we computed and compared crude and premature mortality [three different measures of years of potential life lost (YPLL)] of illnesses caused by Campylobacter spp., Listeria monocytogenes, norovirus, rotavirus, non-typhoidal Salmonella spp., and Shiga toxin-producing E. coli (STEC). Among ~1.5 million notified illnesses, those caused by norovirus were the most frequent. The highest annual mortality was registered for salmonellosis (0.55/1 000 000 population), but listeriosis accounted for the highest number of YPLL (n=4245). Disregarding death at advanced age (i.e. >70 years), STEC illness (n=757) and rotavirus gastroenteritis (n=648) ranked second and third, following listeriosis (n=2306). Routine surveillance captures only a fraction of all incident cases and deaths, under-ascertaining the true burden of disease. Weighting death by age permits a different view on the disease burden individual enteric pathogens cause and particularly underscores the public health importance of listeriosis prevention.

A serosurvey of viruses during outbreaks of acute respiratory and/or enteric disease in Swedish cattle.

This report presents results on the incidence of serum titres and the increase in titres against viruses and Chlamydia (miagawanelia) in Swedish cattle in relation to disease during the period 1973 to 1976. Samples from about 300 animals have been processed. Serological tests with 15 different antigens have been performed including: adenoviruses, parainfluenza-3 virus, virus diarrhoea virus, reoviruses, respiratory syncytial virus and Chlannjdia. Serum antibodies were found against all tested antigens and the frequency ranged from 20 to 80%. The frequency of significant increases in titre in connection with disease varied for the different viruses between 2% and 7%.

A hundred-year retrospective on cryptosporidiosis

Tyzzer discovered the genus Cryptosporidium a century ago, and for almost 70 years cryptosporidiosis was regarded as an infrequent and insignificant infection that occurred in the intestines of vertebrates and caused little or no disease. Its association with gastrointestinal illness in humans and animals was recognized only in the early 1980s. Over the next 25 years, information was generated on the disease's epidemiology, biology, cultivation, taxonomy and development of molecular tools. Milestones include: (i) recognition in 1980 of cryptosporidiosis as an acute enteric disease; (ii) its emergence as a chronic opportunistic infection that complicates AIDS; (iii) acknowledgement of impact on the water industry once it was shown to be waterborne; and (iv) study of Cryptosporidium genomics.

Detection of the New Human Coronavirus HKU1: A Report of 6 Cases

Background. Human coronavirus HKU1 (HCoV-HKU1), a new group 2 coronavirus, was first characterized in 2005 from 2 adults with pneumonia in Hong Kong, China. To the best of our knowledge, there is no other report to date about the detection of this new virus. We report a molecular method allowing for the detection of HCoV-HKU1 and also report the clinical presentation of 6 infected patients. Methods. We screened 141 specimens (135 nasal samples and 6 stool samples) received in February and March 2005 in our laboratory and obtained from 135 hospitalized patients (61.5% of whom were <5 years old and 34.1% of whom were >20 years old) for HCoV-HKU1. Results. HCoV-HKU1 was detected in 6 (4.4%) of the 135 nasal specimens and in 2 (33.3%) of the 6 stool samples; the positive samples were obtained from 6 patients (5 children and 1 adult). The clinical presentation of these 6 patients was as follows: 3 were admitted to the hospital for acute enteric disease resulting in severe dehydration associated with upper respiratory symptoms; 1 had fever, otitis, and febrile seizure; 1 had a sample obtained to investigate failure to thrive; and 1 had a sample obtained for exploration of X-linked agammaglobulinemia and hyperleucocytosis. Conclusion. HCoV-HKU1 can be detected in respiratory and stool samples from children and adults in a part of the world other than Hong Kong. Our results suggest that HCoV-HKU1 could be associated with respiratory and enteric diseases, and its detection can be related to a persistent asymptomatic infection in patients with poor underlying conditions.

Increasing prevalence of quinolone resistance in human nontyphoid Salmonella enterica isolates obtained in Spain from 1981 to 2003.

From January 1981 to December 2003, susceptibility to nalidixic acid was tested in 10,504 nontyphoid Salmonella enterica isolates from patients with acute enteric disease in Gipuzkoa, Spain. The prevalence of nalidixic acid resistance steadily increased from less than 0.5% before 1991 to 38.5% in 2003, mainly due to the increase in resistance among isolates of the most prevalent serovar, S. enterica serovar Enteritidis. For nalidixic acid-resistant isolates, the ciprofloxacin MIC was eightfold higher than that for susceptible isolates, and the nalidixic acid-resistant isolates contained a single point mutation in the gyrA gene (at codons for Ser83 or Asp87). The same mutations were found in a sample of nalidixic acid-resistant nontyphoid Salmonella strains isolated between 1999 and 2003 from retail food for human consumption. In 2003, we identified five S. enterica serovar Typhimurium clinical isolates with high-level fluoroquinolone resistance (ciprofloxacin MIC, 16 microg/ml) with two point mutations in the gyrA gene (coding for Ser83-->Phe and Asp87-->Asn) and one point mutation in the parC gene (coding for Ser80-->Arg). Strict sanitary controls are needed to avoid the spread of ciprofloxacin-resistant serovar Typhimurium isolates, and a more efficient veterinary policy must be adopted to decrease the large burden of Salmonella serovar Enteritidis infections in humans in our region.

A review of the biology and epidemiology of cryptosporidiosis in humans and animals

The epidemiology of cryptosporidiosis, an infection caused by several genotypically and phenotypically diverse Cryptosporidium species, has been dynamically changing over the past decade from that of a rare, largely asymptomatic infection to an acute enteric disease of animals and humans. In this review, the current understanding of factors (biology and epidemiology) contributing to the emergence of cryptosporidiosis in animals, including parasite biology, genetic diversity, environmental spread, livestock production trends, presence of the parasite in livestock and companion animals, and potential risk of transmission from animals to humans is highlighted. Potential control measures and the role of veterinary and medical professionals in the prevention of cryptosporidiosis are also discussed.

Effect of dietary mannanoligosaccharide and sodium chlorate on the growth performance, acute-phase response, and bacterial shedding of weaned pigs challenged with Salmonella entericaserotype Typhimurium1

A 28-d experiment evaluated the growth, acute-phase response, and bacterial shedding patterns in pigs (n = 96; initially 6.8 ± 1.3 kg) fed mannanoligosaccharides (MANNAN) and sodium chlorate (CHLORATE) before and after oral challenge with Salmonella enterica serotype Typhimurium (ST). The negative control diet contained no antimicrobial (CON), and the positive control contained carbadox (CARB; 55 ppm). Test diets contained (as-fed basis) MANNAN (1,500 ppm) or CHLORATE (800 ppm). Pigs were fed diets for 14 d and then given ST orally. Pigs fed CARB had greater ADG over the entire study than pigs from other treatments (P < 0.05). During wk 1 to 2, before ST challenge, feed intake (as-fed basis) was lower for pigs fed MANNAN and CHLORATE than pigs fed CARB (P < 0.05). During the final 2 wk, pigs fed CARB had greater feed intake than pigs on other treatments (P < 0.05). Gain/feed was greater for pigs fed CARB in the 2 wk before ST (P < 0.05); however, in wk 3 to 4 after ST, gain/feed was reduced for CON pigs compared to pigs on other treatments (P < 0.05). Serum IGF-I was decreased at 2 and 4 d after ST (P < 0.001), and, overall, IGF-I was greater in pigs fed CARB than CON or CHLORATE (P < 0.05). Serum haptoglobin concentrations were greater (P < 0.001) for all treatments at d 6 compared with d 13 after ST. Overall, haptoglobin was greater for MANNAN than for CARB and CHLORATE (P < 0.05) and tended to be increased (P < 0.06) relative to CON. Interleukin-6 was not affected by treatment or day post-ST challenge. Fecal shedding of salmonellae organisms was less for CHLORATE (P < 0.05) than all other treatments at 7 d after ST. Shedding scores decreased from d 7 to 14 after ST (P < 0.05) for the CON, CARB, and MANNAN treatments. We conclude that feeding MANNAN and CHLORATE before acute enteric disease challenge may support improved gut function as evidenced by improved gain/feed, and that CHLORATE may decrease bacterial shedding. But neither MANNAN nor CHLORATE enhanced growth relative to the absence of dietary antimicrobials, nor was either treatment as effective as CARB following ST challenge.

Effect of dietary mannanoligosaccharide and sodium chlorate on the growth performance, acute-phase response, and bacterial shedding of weaned pigs challenged with Salmonella enterica serotype Typhimurium.

A 28-d experiment evaluated the growth, acute-phase response, and bacterial shedding patterns in pigs (n = 96; initially 6.8 +/- 1.3 kg) fed mannanoligosaccharides (MANNAN) and sodium chlorate (CHLORATE) before and after oral challenge with Salmonella enterica serotype Typhimurium (ST). The negative control diet contained no antimicrobial (CON), and the positive control contained carbadox (CARB; 55 ppm). Test diets contained (as-fed basis) MANNAN (1,500 ppm) or CHLORATE (800 ppm). Pigs were fed diets for 14 d and then given ST orally. Pigs fed CARB had greater ADG over the entire study than pigs from other treatments (P < 0.05). During wk 1 to 2, before ST challenge, feed intake (as-fed basis) was lower for pigs fed MANNAN and CHLORATE than pigs fed CARB (P < 0.05). During the final 2 wk, pigs fed CARB had greater feed intake than pigs on other treatments (P < 0.05). Gain/feed was greater for pigs fed CARB in the 2 wk before ST (P < 0.05); however, in wk 3 to 4 after ST, gain/feed was reduced for CON pigs compared to pigs on other treatments (P < 0.05). Serum IGF-I was decreased at 2 and 4 d after ST (P < 0.001), and, overall, IGF-I was greater in pigs fed CARB than CON or CHLORATE (P < 0.05). Serum haptoglobin concentrations were greater (P < 0.001) for all treatments at d 6 compared with d 13 after ST. Overall, haptoglobin was greater for MANNAN than for CARB and CHLORATE (P < 0.05) and tended to be increased (P < 0.06) relative to CON. Interleukin-6 was not affected by treatment or day post-ST challenge. Fecal shedding of salmonellae organisms was less for CHLORATE (P < 0.05) than all other treatments at 7 d after ST. Shedding scores decreased from d 7 to 14 after ST (P < 0.05) for the CON, CARB, and MANNAN treatments. We conclude that feeding MANNAN and CHLORATE before acute enteric disease challenge may support improved gut function as evidenced by improved gain/feed, and that CHLORATE may decrease bacterial shedding. But neither MANNAN nor CHLORATE enhanced growth relative to the absence of dietary antimicrobials, nor was either treatment as effective as CARB following ST challenge.

Effects of an acute enteric disease challenge on IGF-1 and IGFBP-3 gene expression in porcine skeletal muscle (2002)

Eighteen pigs (initial weight 25 lb and approximately 5 wk of age) were used in a 14-d trial to determine the effects of an acute Salmonella enterica serotype typhimurium (ST) disease challenge on both circulating insulinlike growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) and steady-state IGF-1 and IGFBP-3 mRNA levels in skeletal muscle. Muscle biopsies and blood samples were obtained from all pigs on d 0, 3, 7, and 14 relative to ST-challenge. Results suggest that an acute ST-challenge decreased circulating IGF-1 levels on d 3 and 7 but did not affect circulating IGFBP-3 concentrations. Additionally, ST-challenge had no effect on steady-state IGF-1 and IGFBP-3 mRNA levels in skeletal muscle following the onset of disease. These data suggest that an acute enteric disease insult can lower circulating IGF-1 but more chronic conditions may be necessary to affect local IGF-1 levels in skeletal muscle. Additionally, the increased muscle IGF-1 mRNA without increased IGFBP-3 levels on d 14 most likely results in increased IGF-1 synthesis that contributes to circulating IGF-1 concentrations.

Effects of mannanoligosaccharide and sodium chlorate on growth performance of nursery pigs during an acute enteric disease challenge with Salmonella enterica serotype typhimurium (2002)

A 28-day experiment was conducted to compare the effects of feeding mannanoligosaccharides (mannan) and sodium chlorate (chlorate) to weanling pigs as a possible substitute for the commonly used antimicrobialcarbadox. Pigs were fed experimental diets for 2 wk, then challenged orally with Salmonella enterica serotype typhimurium to establish enteric disease. Average daily gain and ADFI were greater for pigs fed carbadox than all other treatments in the 2 wk following infection. During the first week after infection, pigs fed chlorate had greater G/F than control pigs, and pigs fed mannan tended to have greater G/F than control pigs. There were no differences in feed efficiency among treatments during the second week following infection.; Swine Day, Manhattan, KS, November 14, 2002

Effects of a Quillaja saponaria extract on weanling pig growth performance and immune function during an acute enteric disease challenge (2000)

A total of 96 pigs (initially 19 lb and 17 d of age) was used in a 28 d growth trial to determine the effects of Quillaja saponaria (QS) extract on weanling pig growth performance and immune function in response to enteric disease challenge with Salmonella typhimurium (ST). Experimental treatments were arranged in a 2 × 4 factorial with main effects of disease challenge (control vs. ST challenge) and dietary addition of QS (0, 4, 8, or 16 oz/ton). The results suggest little beneficial effect of QS on growth performance or immune response in the presence or absence of ST challenge.; Swine Day, Manhattan, KS, November 16, 2000

Effects of a seaweed extract on weanling pig growth performance and immune function during an acute enteric disease challenge (2000)

A total of 95 pigs (initially 15 lb and 17 d of age) was used in a 28 d growth trial to determine the effects of Ascophyllum nodosum seaweed extract (ANOD) on weanling pig growth performance and immune function in response to enteric disease challenge with Salmonella typhimurium (ST). Experimental treatments were arranged in a 2 x 4 factorial with main effects of disease challenge (control vs. ST challenge) and dietary addition of ANOD (0, 0.5, 1.0, and 2.0% of diet). Results suggest little beneficial effect of dietary ANOD on growth performance or immune response in the presence or absence of ST challenge.; Swine Day, Manhattan, KS, November 16, 2000

Presence of adherent Escherichia coli strains in ileal mucosa of patients with Crohn's disease

Background & Aims: Infectious agents are suspected of being involved in the pathogenesis of Crohn's disease. This study was designed to look for the presence of virulent Escherichia coli strains associated with the ileal mucosa of patients with Crohn's disease. Methods: E. coli strains were recovered from resected chronic ileal lesions (n = 20), neoterminal ileum after surgery from patients with (n = 19) and without (n = 11) endoscopic recurrence, and controls (n = 13). Bacterial adhesion was determined in vitro using intestinal cell lines; other associated virulence factors were assessed by DNA hybridization and polymerase chain reaction experiments. Results: None of the strains harbored any of the virulence factor–encoding genes of E. coli involved in acute enteric diseases. However, mannose-resistant adhesion to differentiated Caco-2 cells was found for 84.6% and 78.9% of the E. coli strains isolated from chronic and early recurrent lesions, respectively, compared with 33% of controls ( P < 0.02). In addition, 21.8% of the strains induced a cytolytic effect by synthesis of an α-hemolysin. Conclusions: E. coli strains isolated from the ileal mucosa of patients with Crohn's disease adhere to differentiated intestinal cells and may disrupt the intestinal barrier by synthesizing an α-hemolysin. GASTROENTEROLOGY 1998;115:1405-1413

Implications of the Worldwide Distribution of Shigellosis

Shigellosis, or bacillary dysentery, ranks among the major gastrointestinal diseases afflicting the world’s population. Shigellosis is an acute enteric disease that is attributed to one of four species— S. dysenteriae, S.flexneri, S. boydii , and S. sonnei . Biomedical literature was reviewed to identify the predominant species occurring in a country. Confirmation of the predominant species verified the belief that the level of economic development affects species distribution. Other findings that bear on the variability of pathogenicity include the manner in which the organism is transmitted, the role of malnutrition, and emerging antibiotic resistance.

HLA class I antigen serves as a receptor for human coronavirus OC43.

Human coronaviruses are associated with acute respiratory and enteric disease in man as such their target cells are probably the epithelial cells lining the respiratory and enteric tract. Attachment of virus to specific receptors on the cell surface is a major determinant of virus tropism in pathogenesis (1). Recently, aminopeptidase-N was identified as a cell receptor for the 229e coronavirus (2). Cell receptor(s) for OC43 coronavirus have not been identified. However, it is of pathologic significance that OC43 virus shares DNA sequence homology with the two coronavirus isolates, SK and SD, from the brain of patients with multiple sclerosis (MS) (3). Probing MS and control brain with probes specific for human, murine, porcine and bovine coronavirus by in situ hybridization resulted in the detection of coronavirus RNA in 12 of 22 MS brain samples; five of which were positive with the OC43 probe (4). A study of virus-ligand interactions of OC43 with human rhabdomyosarcoma (RD) cells, which are highly susceptible to virus infection, was undertaken to identify possible cell receptors. The binding of virus collected from the supernatant of infected cells to cell proteins immobilized on nitrocellulose paper was used to screen for virus-ligand interactions. The next step was the identification or development of antibodies to each of the ligands, and to test their ability to blockade receptor activity by culturing infected cells in medium containing the ligand antibodies and measuring the effect on virus yield. The preliminary experiments reported here reveal an interesting observation of strong affinity of OC43 virus for the HLA class I antigen.