Rapid Diagnosis of Respiratory Syncitial Virus A & B and Influenza Virus A & B Pneumonia by Antigen Detection in Children with Community Acquired Pneumonia

Abstract

More than one third of the estimated global mortality of 12-14 millions age under five years has been ascribed to acute respiratory infections. Acute lower respiratory tract infection, especially severe pneumonia was responsible for >75% of these deaths, with two thirds occurring in infants. Community acquired pneumonia. CAP; is still today the most common cause of mortality in children specially among those under the age of 5 years. This is most significant in developing countries, where incidence rates are up to 10 times greater than in developed countries. Almost 2 million children died yearly from acute respiratory infection most from pneumonia. RSV, influenza, are the most common viruses associated with CAP in childhood. Immunofluorescence is one of the most common and rapid respiratory viruses detection techniques used, direct fluorescent antibody assay (DFA) is a standard detection technique used for decades and other RSV detection techniques are often compared to DFA for evaluating their efficiency. This study was conducted at the department of pediatric hospital, Ain Shams University, done for 55 Childs attending with clinical or radiological findings of community- acquired pneumonia. All the patients in this study have been subjected to detailed history taking, clinical, radiological and laboratory assessment which include routine non specific haematological investigations (CBC, C-reactive protein) and routine bacterial culture. Specific test direct immunofluorescence to detect RSV A & B and influenza A & B antigens in respiratory samples. The following results were obtained:  Viral CAP were defined in 38% of studied children with RSV A RSV B, influenza A represent (21.8%, 1.8%, 14.5%) respectively while influenza B was not detected in all studied children.  Bacterial CAP defined in 51% of studied while mixed viral and bacterial CAP in 11% of studied children.  Radiologically incidence of lobar pneumonia was significantly higher in non viral CAP while bronchopneumonia was significantly higher in viral CAP.  Haematologically Lymphocytes count was significantly increased in viral CAP while Neutrophils count was significantly increased in non viral CAP. Conclusion  Respiratory viruses including RSV A & B and influenza virus A & B represent major etiological agent of community acquired pneumonia.  Immunofluorescence is a rapid sensitive, specific and cheapest diagnostic technique that can be used for detection of more than one viral agent causing CAP and for epidemiological studies.