Herpes Simplex Virus Pneumonia: Importance of Aspiration Etiology

Abstract

Herpes simplex virus (HSV) pneumonia caused by aspiration from the oropharyngeal exudates is described. An 89-year-old Japanese male in a poor performance state complained of appetite loss followed by difficulty in swallowing, and bilateral pulmonary infiltrates with interstitial reactions were radiologically pointed out. Antibiotics administration was ineffective, and he died on the 6th day of hospitalization. At autopsy, HSV-induced multiple mucosal erosions were observed on the tongue, pharynx, epiglottis, and trachea. In bilateral lower lobes of the lung, HSV infected bronchiolar and type-II alveolar cells in association with acute interstitial reactions. The infected cells with intranuclear inclusion bodies were immunoreactive with HSV antiserum. HSV-1 infection was confirmed by immunostaining with monospecific monoclonal antibodies and by type-specific real-time polymerase chain reaction. It is very likely that HSV pneumonia was provoked by aspiration of infected exudates from the upper airway (namely, sequential infection from the tongue, epiglottis, and trachea to lung). Oropharyngeal herpes might cause anorexia and difficulty in swallowing, probably accelerating aspiration. The medical staff did not recognize the oropharyngeal lesions of this aged patient. We must realize again the importance of oral care for hospitalized patients to avoid aspiration pneumonia, including herpetic pneumonia.

SARS-CoV-2 Reverse Genetics Reveals a Variable Infection Gradient in the Respiratory Tract

“…In contrast, it is well-known that an oral-lung aspiration axis is a key contributor to many lower airways infectious diseases (Dickson et al, 2016;Esther et al, 2019;Gaeckle et al, 2020;Odani et al, 2019;Phillips et al, 2015). Nasal secretions are swept from the nasal surface rostrally by mucociliary clearance and accumulate in the oral cavity at a rate of $0.5 mL/h where they are admixed with oropharyngeal or tonsillar fluid (Eichner et al, 1983;Pandya and Tiwari, 2006).…”

Cellular and Molecular Effects of SARS-CoV-2 Linking Lung Infection to the Brain

“…Although the main route for the most viral infections of the lower airways is considered to be the oral-lung aspiration axis (102,103), research of the novel coronavirus SARS-CoV-2 suggests that in this case, the more prevalent entry is via the aspiration of oropharyngeal mucus originating from the nasal cavity and containing the viral inoculum, into the deep lung. Evidence supporting this hypothesis comes from the knowledge that the nasal lining has a higher concentration of the ACE2 receptor compared to the lower airways, creating a gradient of high susceptibility of infection in the nasal cavity to lower parts in the deep areas of the lung (104).…”

Possible effects of air temperature on COVID‐19 disease severity and transmission rates

“…11,[51][52][53][54] For many lower respiratory tract infectious diseases, oral-lung aspiration contributes to disease progression and severity. 11,[55][56][57][58][59] Nasal secretions containing relatively high viral titers can accumulate in the oropharynx and are predicted to subsequently spread to lower airways via aspiration. 11,[60][61][62][63][64] Chest CT and autopsy studies from COVID-19 patients indicate patchy pulmonary infection, consistent with aspiration of virus into the lung from the upper respiratory tract.…”

“…The abundance of ACE2 on luminal surfaces of conducting airway epithelium may enable considerable and progressive viral growth and spread throughout the airways 11,51–54 . For many lower respiratory tract infectious diseases, oral‐lung aspiration contributes to disease progression and severity 11,55–59 . Nasal secretions containing relatively high viral titers can accumulate in the oropharynx and are predicted to subsequently spread to lower airways via aspiration 11,60–64 .…”

“…11,[51][52][53][54] For many lower respiratory tract infectious diseases, oral-lung aspiration contributes to disease progression and severity 11,[55][56][57][58][59]. Nasal secretions containing relatively high viral titers can accumulate in the oropharynx and are…”