Human Metapneumovirus Infection In Children with Cancer

Abstract 3910

The human metapneumovirus (HMPV) is a paramyxovirus that has been recently associated with respiratory tract infections in children. HMPV was first described in 2001 by researchers in the Netherlands. Since this initial report, HMPV has been reported from many other countries across the world. HMPV was found to be the second most frequent cause, after RSV, of viral respiratory infections in children less than 1 year of age. In hospitalized children, the most frequent clinical manifestations associated with HMPV are pneumonitis, bronchiolitis and asthma. Severe HMPV infection can also occur in the elderly and in immunocompromised patients. We carried out a retrospective study to describe the clinical features and severity of HMPV in pediatric oncology patients at The Hospital for Sick Children.

Thirty one children with cancer found to have HMPV infection during the study period from January 2005 till December 2010. HMPV was isolated by nasopharyngeal (NP) swab in 30/31 patients while one patient had bronchalveolar lavage (BAL). Direct fluorescent-antibody (DFA) was positive in all 31 patients while 13 patients also had viral culture positive. Eight patients had culture negative while this test was not done in 10 patients (after December 2008). The majority of HMPV infection was diagnosed in the winter months from November to March and also in the spring till May. Of 31 patients, 13 were male and 18 were female. The most common underlying diagnosis was leukemia 14/31 (45.1%). Nine patients had different types of solid tumours including 3 with neuroblastoma, 2 with rhabdomyosarcoma, 1 with hepatoblastoma, 1 with nasopharyngeal sarcoma, and 1 with undifferentiated sarcoma. Twenty-nine of thirty-one (93.5%) of the patients presented with cough, 24/31 (77.4%) with fever, 16/31 (51.6%) with rhinorrhea. Vomiting was noticed in 25.8% of the patients and diarrhea in 32.2%. Sixteen of thirty-one (51.6%) patients were diagnosed with upper respiratory tract infection (URTI), 7/31 (22.5%) patients were diagnosed as bronchiolitis and 8/31 (25.8%) diagnosed to have pneumonia. 19.3% (6/31) patients had co-infection with different organisms including coagulase negative Staphylococcus and Streptococcus pneumoniae requiring antibiotic treatment. The average duration of symptoms on presentation was 7 days (1-90 days). One patient with average risk acute lymphoblastic leukemia on maintenance treatment presented with 3 months history of cough and subsequently NP swab and BAL were positive for HMPV. He required prolonged therapy with inhaled bronchodilator and steroid. Twenty of thirty-one (64.5%) patients were admitted. The average duration of admission was 18.3 days and average duration of respiratory illness was 13.5 days. None of the patient required mechanical ventilation because of HMPV infection. Twenty-one of thirty-one patients were treated with antibiotics for duration of 3 to 14 days. One patient was empirically treated with oseltamivir (Tamiflu). All of the patients recovered from their viral illness completely, only one patient had prolonged respiratory symptoms for six months.