Detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus 3 in dual-purpose farms in Colima, Mexico.

A cross-sectional study was carried out, from November 2007 to March 2008, to estimate the prevalence of and to determine risk factors associated with bovine syncytial respiratory virus (BRSV) and parainfluenza 3 virus (PIV3) in dual-purpose herds in Colima, México. One hundred and seventy-six sera from 33 herds for PIV3 and 232 sera from 44 herds for BRSV were used. Sera were analyzed by indirect ELISA for the detection of antibodies against BRSV and PIV3 in cattle herds to determine the seroprevalence of respiratory diseases. The apparent and true prevalences for PIV3 were 60.8% and 54.4% and for BRSV 52.2% and 50.8%, respectively. The percentage of herds showing at least one positive animal was 78.7% for PIV3, and 93.2% for BRSV. Age (≤ 12, 13-48, and >48 months old) and respiratory signs (no, yes) showed significant association (P < 0.05) with PIV3 and age with BRSV. This study showed that animals were exposed to both viruses and that age was the main risk factor. The need to establish new vaccination plans to effectively protect cattle against those infections in the state of Colima, Mexico is suggested.

Multigenic control of resistance to Sendai virus infection in mice.

Experimental infection of mice with Sendai virus (SeV) is frequently used as a model of viral pathogenesis of human respiratory disease. To understand the differences in host response to SeV among mice strains, we carried out genetic mapping studies in DBA/2 (D2) (susceptible) and C57BL/6 (B6) (resistant) mice. F(1), F(2), and N(2) backcrossed mice were generated and examined for their disease resistance and susceptibility. For the determination of virulence, percentage body weight loss and survival time were used as phenotypes. We, then, carried out a genome wide scan on 108 backcrossed mice for linkage with percentage body weight loss as phenotype. A major quantitative trait locus (QTL) showing significant linkage was mapped to the distal portion of Chr 4 (SeV1). In addition, two other QTLs showing suggestive statistical linkage were also detected on Chr 8 and 14. We, further, performed genome scan for interactions with least squares analysis of variance of all pairs of informative makers in backcrossed progenies. We identified a highly significant epistatic interaction between D3Mit182 and D14Mit10, then denoted as SeV2 and SeV3, respectively, and the latter was the same locus showing a suggestive level on Chr 14 in QTL analysis. Considered genotypes of these three loci, we could account for more than 90% of genetic effect on the differential response to SeV infection between B6 and D2 mice. These findings revealed a novel gene interactions controlling SeV resistance in mice and will enable the identification of resistance genes encoded within these loci.

Bovine viral diarrhea viral infections in feeder calves with respiratory disease: interactions with Pasteurella spp., parainfluenza-3 virus, and bovine respiratory syncytial virus.

The prevalence of bovine viral diarrhea virus (BVDV) infections was determined in a group of stocker calves suffering from acute respiratory disease. The calves were assembled after purchase from Tennessee auctions and transported to western Texas. Of the 120 calves, 105 (87.5%) were treated for respiratory disease. Sixteen calves died during the study (13.3%). The calves received a modified live virus BHV-1 vaccine on day 0 of the study. During the study, approximately 5 wk in duration, sera from the cattle, collected at weekly intervals, were tested for BVDV by cell culture. Sera were also tested for neutralizing antibodies to BVDV types 1 and 2, bovine herpesvirus-1 (BHV-1), parainfluenza-3 virus (PI-3V), and bovine respiratory syncytial virus (BRSV). The lungs from the 16 calves that died during the study were collected and examined by histopathology, and lung homogenates were inoculated onto cell cultures for virus isolation. There were no calves persistently infected with BVDV detected in the study, as no animals were viremic on day 0, nor were any animals viremic at the 2 subsequent serum collections. There were, however, 4 animals with BVDV type 1 noncytopathic (NCP) strains in the sera from subsequent collections. Viruses were isolated from 9 lungs: 7 with PI-3V, 1 with NCP BVDV type 1, and 1 with both BVHV-1 and BVDV. The predominant bacterial species isolated from these lungs was Pasteurella haemolytica serotype 1. There was serologic evidence of infection with BVDV types 1 and 2, PI-3V, and BRSV, as noted by seroconversion (> or = 4-fold rise in antibody titer) in day 0 to day 34 samples collected from the 104 survivors: 40/104 (38.5%) to BVDV type 1; 29/104 (27.9%) to BVDV type 2; 71/104 (68.3%) to PI-3V; and 81/104 (77.9%) to BRSV. In several cases, the BVDV type 2 antibody titers may have been due to crossreacting BVDV type 1 antibodies; however, in 7 calves the BVDV type 2 antibodies were higher, indicating BVDV type 2 infection. At the outset of the study, the 120 calves were at risk (susceptible to viral infections) on day 0 because they were seronegative to the viruses: 98/120 (81.7%), < 1:4 to BVDV type 1; 104/120 (86.7%) < 1:4 to BVDV type 2; 86/120 (71.7%) < 1:4 to PI-3V; 87/120 (72.5%) < 1:4 to BRSV; and 111/120 (92.5%) < 1:10 to BHV-1. The results of this study indicate that BVDV types 1 and 2 are involved in acute respiratory disease of calves with pneumonic pasteurellosis. The BVDV may be detected by virus isolation from sera and/or lung tissues and by serology. The BVDV infections occurred in conjunction with infections by other viruses associated with respiratory disease, namely, PI-3V and BRSV. These other viruses may occur singly or in combination with each other. Also, the study indicates that purchased calves may be highly susceptible, after weaning, to infections by BHV-1, BVDV types 1 and 2, PI-3V, and BRSV early in the marketing channel.

Immunogenicity of purified F glycoprotein of respiratory syncytial virus: clinical and immune responses to subsequent natural infection in children.

Purified F glycoprotein from respiratory syncytial virus (RSV, subgroup A antigenic type) was evaluated in 18- to 36-month-old children as a vaccine. Children had been previously infected with RSV during natural outbreaks of the virus. Single injections of 5, 20, or 50 micrograms of protein resulted in greater than eightfold increases in ELISA and neutralizing antibodies. Second doses of vaccine did not result in further boosts in antibody. Neutralizing antibodies increased not only to the A2 and Long strains (subgroup A strains) but also to strain 18537 (subgroup B). Four of 11 vaccinees became naturally infected during the subsequent RSV outbreak, suggesting that the vaccine was not effective in preventing recurrent RSV infections. Severe illnesses did not occur, indicating that there was not an increase of severity of infection following vaccine in seropositive children. Only 1 of 8 vaccinees tested had fourfold increases in nasal wash IgA to RSV after immunization. Vaccine strategies to stimulate secretory antibodies as well as circulating neutralizing antibodies to RSV need to be developed.

Respiratory syncytial virus infection in lower respiratory tract and asthma attack in hospitalized children in North Hokkaido, Japan.

Respiratory syncytial virus (RSV) infection is severe and life-threatening in some infants. To investigate the epidemiology of RSV infection in hospitalized children in North Hokkaido, Japan, we tried to detect RSV antigen in nasopharyngeal aspirates (NPA) from those children with lower respiratory tract infection (LRTI) and asthma attack. From April 1991 to March 1992, 317 patients were hospitalized in our pediatric ward for the treatment of LRTI and asthma attack. The presence of RSV antigen in NPA taken from 283 patients (89.3%) were examined by enzyme immunoassay. RSV antigen was detected in 88 patients (31.1%). RSV LRTI were noted throughout the year, and the epidemic peak was observed in November and December. There was no significant correlation between the RSV antigen positive rate and mean temperature. RSV played an important role in LTRI in children in North Hokkaido, Japan. RSV LRTI in North Hokkaido was not rare in summer, indicating that RSV was transmitted commonly among children throughout the year.

[Pneumonia due to respiratory syncytial virus diagnosed by transtracheal aspiration in an adult].

A healthy-looking 44-year-old female was admitted to our hospital complaining of fever and hemosputum. The chest roentgenogram on admission showed patchy infiltrates of the segment 3 and 8 of the right lung. Laboratory studies showed a leukocyte count of 9700/microliters, erythrocytes sedimentation rate of 55 mm/hour and C reactive protein of 8.7 mg/dl. The arterial PO2 was 71.9 torr while the patient was breathing room air. Transtracheal aspiration was performed on admission, and strains and culture for bacteria, acid fast bacilli, fungi and mycoplasma were negative. Respiratory syncytial virus was isolated from transtracheal aspirates. The RSV complement fixing antibody titers rose from 1:40 to 1:16. She became afebrile on the fourth day after admission and her chest roentgenogram improved gradually. RSV infection should be considered in the differential diagnosis of atypical adult pneumonias.

SP-303 small-particle aerosol treatment of influenza A virus infection in mice and respiratory syncytial virus infection in cotton rats.

A natural plant product, SP-303, was administered by small-particle aerosol to influenza A/HK virus-infected mice and RSV-infected cotton rats. Aqueous SP-303 at 2 mg/ml in the Collison nebulizer reservoir generated an aerosol with an output of 26 micrograms/l and a particle size distribution of 1.4 microns +/- 4.6 (MMAD +/- GSD). SP-303 at a dosage of 0.5-9.4 mg/kg per day administered for 3-4 days significantly increased both the rate and duration of survival of mice lethally infected with influenza A/HK virus. SP-303 was toxic to mice at 16 mg/kg per day as indicated by weight loss and a decrease in the duration of survival compared to control animals. From these data, a maximum therapeutic index (T.I.) of 12 was calculated. SP-303 given 3-4 days at dosages of 1.3-9.8 mg/kg per day was effective in reducing the pulmonary titer of RSV in infected cotton rats. However, at the 18.7 mg/kg per day dose a significant weight loss compared to control animals was observed; a T.I. of < or = 14 was estimated. These experiments demonstrate that aerosol administration of SP-303 was effective in the treatment of influenza A-infected mice and of RSV-infected cotton rats.

Effect of respiratory syncytial virus infection on binding of Neisseria meningitidis and Haemophilus influenzae type b to a human epithelial cell line (HEp-2).

It has been suggested that individuals might be more readily colonized with bacteria that cause meningitis through enhanced binding of the bacteria to virus-infected epithelial cells. As respiratory syncytial virus (RSV) affects infants and children in the age group also susceptible to bacterial meningitis, we tested the hypothesis that infection of HEp-2 cells by RSV might enhance binding of Neisseria meningitidis or Haemophilus influenzae type b (Hib). Attachment of fluorescein-labelled bacteria to HEp-2 cells was measured by flow cytometry, and RSV-infected cells bound significantly more meningococci (P < 0.001) and Hib (P < 0.01) than uninfected cells. Although the isolates expressed different antigenic characteristics (3 meningococci and 5 Hib), all showed a similar pattern of binding. The results are discussed with reference to the methods used for detection of bacterial binding and to interactions that might explain the increased binding to RSV-infected cells.

[Respiratory virus infections in children]. / Viroses respiratoires chez l'enfant.

Eighty to ninety percent of pathogens responsible for acute respiratory infections in children are viruses, but despite advances in virology these organisms are isolated in only 20 to 45 percent of the cases. Studies conducted outside hospitals have provided epidemiological data. The virus most frequently encountered is the respiratory syncytial virus. The main clinical feature of these respiratory viral infections is obstruction of the bronchioles, and their immediate or delayed danger is the risk of chronic obstructive bronchitis. Treatment is symptomatic, but specific antiviral agents, notably ribavirin, are useful in severe infections.

A lamb model for human respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) is the most important cause of bronchiolitis and pneumonia in young children. The development of an animal model of RSV disease serves to better understanding the pathophysiology of airway disease from RSV infection in infants and children. Groups of six lambs were inoculated intratracheally (IT) or intranasally (IN) with a human strain of RSV (H-RSV). For controls 8 lambs received IT virus-free cell lysate. Tachypnea and fever were observed significantly more often following IT than following IN inoculation of H-RSV or IT placebo (for tachypnea: 20 of 69 days, 5 of 63 days, and 3 of 89 days, respectively, P < 0.001; for fever: 6 of 69 days, 0 of 63 days, and 1 of 89 days, respectively, P < 0.02). Nasal fluid production was significantly more frequent in both IT (14 of 69 days) and IN (15 of 63 days) groups than in the placebo group (2 of 87 days, P < 0.001). Postvaccination geometric mean titers (GMT, arithmetic transformation of log 2) of RSV-specific neutralizing antibody were significantly increased in the IT H-RSV group compared with postplacebo GMTs at 1 week (72 vs. 6.7, P < 0.03). By the second week postinoculation both H-RSV-infected groups had comparable levels of RSV-specific neutralizing antibody titers and had significantly greater GMTs for the second through to the fourth week than the placebo group (144, 128, and 4.8, respectively P < 0.0008). Bacterial isolates of the upper airway were comparable among the three groups. Histopathology at day 28 postinoculation was unremarkable for the three study groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigenic and nucleic acid analysis of nosocomial isolates of respiratory syncytial virus.

Monoclonal antibodies and ribonuclease protection were used to analyze antigenic and genomic diversity among 42 isolates of group A respiratory syncytial virus (RSV) from studies of nosocomial RSV carried out at the University of Rochester during the 1974-1975 and 1975-1976 RSV seasons. Three distinct subgroups or lineages and a total of 12 viral variants were present. Against this background of diversity, an outbreak was recognized that included 13 indistinguishable isolates occurring during a 2-week period. This outbreak accounted for 6 of the 8 infants with nosocomial infection. In contrast to the limited diversity of the nosocomial isolates, isolates from the 10 infants with community-acquired infection included 8 variants. Like those from community outbreaks of RSV, isolates of RSV from hospitalized patients are virologically heterogeneous. However, discrete outbreaks associated with transmission of a single strain can occur.

The antiviral activity of SP-303, a natural polyphenolic polymer, against respiratory syncytial and parainfluenza type 3 viruses in cotton rats.

SP-303, a naturally occurring polyphenolic polymer (average M.W. = 2100 Da), was tested in cotton rats (Sigmoden hispidus) for antiviral activity against respiratory syncytial (RSV) and parainfluenza type 3 (PIV3) viruses, and for acute toxicity. Significant reductions in pulmonary RSV titers, compared to pulmonary RSV titers in comparably treated control animals, were seen in cotton rats given 1-10 mg SP-303/kg/day intraperitoneally (i.p.) on days 1 through to 3, after experimental inoculation with RSV. The minimum efficacious dose of SP-303 against PIV3, when given i.p. for 3 days, was 3 mg/kg/day. Higher doses of SP-303 could not be given i.p., as doses > or = 30 mg/kg/day given once daily by this route for 3 or more consecutive days caused both significant weight loss and death in infected or uninfected animals. Although no toxicity was observed following oral administration of up to 270 mg of SP-303 daily for 3 days, this compound had variable antiviral activity when given by this route.

Enzyme immunoassay for respiratory syncytial virus: rapid detection in nasopharyngeal secretions and evaluation of isolates representing different RSV subgroups.

The presence of respiratory syncytial virus (RSV) was investigated by immunofluorescent antibody (IFA) technique and by an enzyme immunoassay (EIA) in 169 samples of nasopharyngeal secretions of infants and children with acute respiratory infections. Of 31 samples positive by EIA, 25 were positive by IFA. In 24 samples from a retrospective study, RSV positive by IFA and/or tissue culture isolation (TCI), 22 were also positive by EIA. The EIA was also evaluated with 111 RSV isolates in Hep2 cell cultures representing different RSV subgroups. All were positive by EIA.

Protection of goats against peste des petits ruminants with a vaccinia virus double recombinant expressing the F and H genes of rinderpest virus.

Peste des petits ruminants (PPR) is a viral disease of goats and sheep characterized by necrotizing and erosive stomatitis, enteritis and pneumonia. The causative agent, PPRV, is a member of the family Paramyxoviridae and the genus Morbillivirus. Other members of the genus include rinderpest (RPV), measles, canine distemper and phocid distemper viruses. PPR has a very high rate of morbidity and mortality, and effective control of this disease is of economic importance in Africa, Asia and the Middle East. Currently, there is no safe and effective vaccine available against the disease. The tissue culture rinderpest vaccine (TCRV) protects small ruminants against severe disease; there are, however, clinical problems associated with vaccination. This laboratory has recently developed several effective vaccinia virus recombinant vaccines for rinderpest. These vaccines are easy to administer, inexpensive to produce and heat-stable. Goats were vaccinated with a vaccinia virus double recombinant expressing the haemagglutinin and fusion genes of RPV. Although vaccinated animals developed antibodies (neutralizing and ELISA) to RPV, and not to PPRV, they were completely protected against challenge inoculation with virulent PPRV. This would indicate that protection is most probably due to cell-mediated immunity. Use of the rinderpest double recombinant vaccinia virus in areas of the world where PPRV is endemic would aid in the control and eradication of PPR.

Morbillivirus infections in aquatic mammals.

Infections with morbilliviruses have caused heavy losses among different populations of aquatic mammals during the last 5 years. Two different morbilliviruses were isolated from disease outbreaks among seals in Europe and Siberia: phocid distemper virus-1 (PDV-1) and phocid distemper virus-2 (PDV-2) respectively. PDV-1 was characterized as a newly identified morbillivirus, most related to canine distemper virus (CDV), whereas PDV-2 most probably is a strain of CDV. Morbilliviruses were also isolated from porpoises--porpoise morbillivirus (PMV)--and dolphins--dolphin morbillivirus (DMV)--which had stranded on the coasts of Europe. PMV and DMV proved to be closely related to, but distinct from 2 ruminant morbilliviruses, rinderpest virus (RPV) and peste-des-petits-ruminants virus (PPRV). Serological surveys carried out among pinniped and cetacean species in the seas of Europe and North America indicated that infections with these newly discovered morbilliviruses or closely related viruses commonly occur among aquatic mammal species.

Stability of respiratory syncytial virus antigen due to buffer treatment for direct detection in nasopharyngeal specimens with enzyme immunoassay.

We developed an enzyme immunoassay (direct EIA; Enzygnost RSV[Ag]) for the direct detection of respiratory syncytial virus (RSV) antigen in nasopharyngeal specimens (NPS). The test procedure is the same as our recently described direct EIA for detection of influenza A and B virus antigens in NPS. For practical purposes it is of advantage to differentiate respiratory viruses on the same microtitration plate in the same run. The test shows no limitations by sample consistency, and results are obtained within 4 hr. In contrast to other test systems, sonification is not necessary. This is due to the sample buffer STD. We studied the influence of sample buffer STD on the stability of RSV (strain Long) antigen at different temperatures over a period of 7 days. PBS-BSA-buffer served as control. The treatment and storage of RSV (strain Long) with sample buffer STD at room temperature or at 4 degrees C showed no decrease of antigen detectability. The antigen is very stable in contrast to the storage of RSV (strain Long) in PBS-BSA buffer during the observation period of 7 days. Consequently, when NPS are stored in sample buffer STD, results of direct EIA are independent from the time of transport and temperature within 7 days. Thirty-eight NPS from infants with confirmed RSV infection were investigated. Confirmation was performed by virus isolation (n = 29) or with commercially available enzyme immunoassays or immunofluorescence test (n = 9). The direct EIA showed a specificity of 99.3% (n = 140) and a sensitivity of 95% (n = 38).