Utility of a respiratory virus panel containing a monoclonal antibody pool for screening of respiratory specimens in nonpeak respiratory syncytial virus season

Efficacy and safety of interferon on neonates with respiratory syncytial virus pneumonia

Respiratory syncytial virus (RSV) pneumonia is a leading cause of hospitalization and mortality among neonates worldwide, and there are currently no specific clinical treatments for RSV infection. Interferons (IFNs) possess broad-spectrum antiviral properties, and the present study aimed to evaluate the efficacy and safety of IFN-α1b for the treatment of neonatal RSV pneumonia. Neonates with RSV pneumonia were divided into the treatment (126 neonates) and control (160 neonates) groups, the former of which were treated with IFN. Aside from IFN administration, both groups received the same routine treatments. There were no significant differences in patient characteristics between the two groups. All neonates in the two groups displayed symptoms such as a cough (93.0%), tachypnea (90.1%), perilabial cyanosis (67.8%), choking on milk (62.9%) and moist rales (58.4%), and no significant differences in the occurrence of these symptoms were observed between the groups (P>0.05). The percentage of cases with bacterial co-infection was 66.8% (191/286), and the bacterial species in the spectrum primarily included Escherichia coli (21.5%), Klebsiella pneumonia (20.4%), Staphylococcus aureus (17.2%), Acihetobacter baumanii (13.1%) and Pseudomonas aeruginosa (9.9%). There were no significant differences in the co-infection rate or bacterial spectrum between the two groups. The remission time of cough, tachypnea, choking on milk, perilabial cyanosis, moist rales and oxygen inhalation in the treatment group was significantly lower compared with the control group (P<0.05). Although the hospitalization time in the treatment group was shorter compared with the control group, the difference was not significant. There were two patients in the treatment group that developed fever within 2-6 h after receiving IFN-α1b, though no other adverse effects were observed. In conclusion, IFN-α1b treatment improved the symptoms associated with neonatal RSV pneumonia with minimal adverse effects.

Severe respiratory disease and its relationship with respiratory viruses in Colombia

BACKGROUND

There are important gaps in our understanding of the epidemiology of respiratory virus infections in tropical countries. In September 2003, the Colombian epidemiological surveillance system was notified of several deaths from an acute respiratory disease (ARD).

METHODS

In order to identify the agents associated with ARD cases, a clinical and laboratory-based surveillance system was implemented throughout the country.

RESULTS

Between September 19 and December 31, 2003, 64 suspected cases of ARD were reported; of these reported cases, 21 (33%) died. Among 25 patients who underwent virus studies, influenza A (H3N2) (n=7) was the most frequently identified agent. Other viruses included parainfluenza (4), influenza B (1), and respiratory syncytial virus (3). The peak occurrence of cases and deaths coincided with the replacement of the influenza A (H3N2) Panama strain, which had been circulating in Colombia since 1999, by three new influenza A (H3N2) strains (Korea, Fujian, and Wyoming).

CONCLUSIONS

This outbreak led to the strengthening of surveillance for respiratory viruses and to new national recommendations for influenza vaccination in Colombia.

Detection of respiratory viruses in nasopharyngeal secretions with immunofluorescence technique for multiplex screening—an evaluation of the Chemicon assay

BACKGROUND

Antigen detection with immunofluorescence is an efficient method for diagnosis of respiratory tract infections, but has previously not allowed for simple screening of many respiratory viruses. Pools of monoclonal antibodies against various respiratory viruses are now available, and are potentially important tools for improvement of antigen detection in nasopharyngeal samples.

OBJECTIVE

To evaluate the commercially available Chemicon immunofluorescence assay (IFA; respiratory viruses panel and identification kit), an indirect IFA containing a pool of monoclonal antibodies for screening for influenza A, B, respiratory syncytial virus (RSV), parainfluenza 1, 2, 3 and adenovirus, and the respective individual antibodies.

STUDY DESIGN

Ninety-six frozen preparations from nasopharyngeal secretions or bronchoalveolar lavages were retrospectively examined with the assay, and the results compared with other IFAs for antigen detection and cell culture isolation obtained in the everyday routine. Nasopharyngeal preparations from 300 children with lower respiratory tract infections at Beijing Children's Hospital during the 1994-1995 winter season were also examined.

RESULTS

The sensitivity of the Chemicon assay compared to the combined results of routine IFA and isolation was 89% and specificity 92%. If five identifications of RSV made with the Chemicon assay alone were regarded to be truly positive, the specificity was 100%. A viral etiology was identified in 105/280 (38%) evaluable samples drawn from the Chinese children (influenza A 20%, RSV 14%, adenovirus 3% and parainfluenza 1, 2 or 3, 7%).

CONCLUSION

One problem with the Chemicon assay was that for around 4-13% of samples there was a non-specific staining in the screening assay, necessitating stainings for verification. Despite this, the assay is an excellent tool for identification of viral respiratory tract infections, giving an increased sensitivity compared to direct immunofluorescence assays.