Herpes simplex virus type 1 and normal protein permeability in the lungs of critically ill patients: a case for low pathogenicity?

INTRODUCTION: The pathogenicity of late respiratory infections with herpes simplex virus type 1 (HSV-1) in the critically ill is unclear. METHODS: In four critically ill patients with persistent pulmonary infiltrates of unknown origin and isolation of HSV-1 from tracheal aspirate or bronchoalveolar lavage fluid, at 7 (1-11) days after start of mechanical ventilatory support, a pulmonary leak index (PLI) for 67Gallium (67Ga)-transferrin (upper limit of normal 14.1 x 10(-3)/min) was measured. RESULTS: The PLI ranged between 7.5 and 14.0 x 10(-3)/min in the study patients. Two patients received a course of acyclovir and all survived. CONCLUSIONS: The normal capillary permeability observed in the lungs argues against pathogenicity of HSV-1 in the critically ill, and favors that isolation of the virus reflects reactivation in the course of serious illness and immunodepresssion, rather than primary or superimposed infection in the lungs

Clinical correlates of herpes simplex virus type 1 loads in the lower respiratory tract of critically ill patients

Background: The significance of isolation of herpes simplex virus (HSV) type 1 from the lower respiratory tract in critically ill patients on mechanical ventilation is still unclear. In the current study, we used polymerase chain reaction techniques to quantify HSV-1 to further evaluate its role. Objectives: The hypothesis was that high loads reflect invasive pulmonary disease related to prolonged mechanical ventilation and increased mortality, as opposed to shedding from the upper respiratory tract, which leads to lower viral loads. Study design: We prospectively studied 77 consecutive patients admitted to the intensive care unit and analyzed 136 tracheal aspirates or bronchoalveolar lavage fluids, taken when clinically indicated in the diagnostic workup of fever, radiologic pulmonary infiltrates, progressive respiratory insufficiency or combinations. Samples were cultured for bacteria and yeasts according to routine microbiological methods and HSV-1 loads were determined by real time quantitative PCR. Viral loads were expr Results: HSV-1 load was directly related to the simplified acute physiology score II (r(s) = 0.47, P = 0.04) when the first specimen taken proved positive for HSV-1. HSV-1 positivity concurred with Candida spp. colonization. Patients with and without a HSV-1 load did not differ with respect to pulmonary and systemic courses and vital outcomes. Conclusions: The data suggest that HSV-1 in the lower respiratory tract originates from shedding in the upper respiratory tract in about 30% of critically ill patients, following immune suppression and reactivation, without invasively infecting the lung. No attributable mortality was observed. (C) 2013 Elsevier B. V. All rights reserved

Respiratory herpes simplex virus type 1 infection/colonisation in the critically ill: marker or mediator?

0.05) in the former. Survivors had a somewhat greater fall in body temperature after a 10-day course of antiviral therapy than non-survivors, but the lung radiographic abnormalities prior to and after the course did not differ. There were no major differences in cardiorespiratory variables between outcome groups and causes of death and were judged not to relate, in general, to HSV-1. CONCLUSIONS: Critically ill patients in whom HSV-1 from BAL is isolated, have about 40% chance of dying, mainly because of severe underlying disease and comorbidity, which may predispose to endogenous reactivation of the virus. There is no clinical evidence for direct cardiorespiratory pathogenicity and beneficial effects of antiviral therapy. HSV-1 isolated from lung secretions may thus be a marker rather than a mediator of severe illness