Respiratory syncytial virus infects the Bonnet monkey, Macaca radiata.

The Bonnet monkey model of respiratory syncytial virus (RSV) infection may be a useful nonhuman primate model for studying RSV disease in humans because Bonnet monkeys can predictably be infected to obtain an orderly sequence of morphologic, cytologic, virologic, serologic, and inflammatory changes related to time of infection. Young feral Bonnet monkeys, Macaca radiata, were infected endotracheally with 10(6) plaque-forming units (pfu) of the Long strain of RSV. RSV was recovered from the animals' lungs at necropsy on days 3, 5, and 7 with the highest viral titer obtained on day 3 (1.1 and 5.2 x 10(3) pfu/g of tissue in the upper and lower lobes, respectively). RSV antigen and F protein mRNA were detected 3-5 days after infection in alveolar macrophages and in the epithelium of bronchi, terminal bronchioles, and alveoli. Histologic analysis of RSV-infected lungs at necropsy revealed progressive bronchiolar mucosal and submucosal inflammation, periarterial mononuclear interstitial inflammation, and focal alveolitis, with a maximal response at 7 days after infection. Cell counts in bronchoalveolar lavage (BAL) increased with time with neutrophils and macrophages predominating on day 3 (6.47 and 5.85 x 10(5)/mm3, respectively) and lymphocytes predominating on day 9 (4.18 x 10(5)/mm3). Serum-neutralizing antibody appeared on day 5 and IgG antibody to RSV was detected on day 9. This sequence of morphologic, cytologic, virologic, serologic, and inflammatory change following RSV infection creates a useful model in the study of experimentally induced RSV disease with a potential for testing future vaccine-induced alterations in RSV disease response.

Resolution of atrial standstill in a child with myocarditis.

Atrial standstill is a rare disorder usually seen in adults with extreme myocardial disease. Etiologies described in the literature have included muscular dystrophy, familial amyloidosis, and rarely myocarditis. These etiologies usually lead to permanent atrial standstill and require ventricular pacing. We present a case of an 11-year-old black female who developed atrial standstill secondary to biopsy proven acute necrotizing myocarditis. Absence of atrial function was confirmed by surface electrocardiogram, echocardiogram, and an invasive electrophysiology study. Atrial function returned within 3 days of initiation of methyl-prednisolone. In cases of atrial standstill due to myocarditis, a delay in the placement of a permanent pacemaker with or without a trial of methylprednisolone may prove beneficial.