Viral respiratory illnesses

Hepatic Manifestations of Nonhepatotropic Infectious Agents Including Severe Acute Respiratory Syndrome Coronavirus-2, Adenovirus, Herpes Simplex Virus, and Coxiella burnetii

Nonhepatotropic viruses such as adenovirus, herpes simplex virus, flaviviruses, filoviruses, and human herpes virus, and bacteria such as Coxiella burnetii, can cause liver injury mimicking acute hepatitis. Most of these organisms cause a self-limited infection. However, in immunocompromised patients, they can cause severe hepatitis or in some cases fulminant hepatic failure requiring an urgent liver transplant. Hepatic dysfunction is also commonly seen in patients with severe acute respiratory syndrome coronavirus-2 infection. Patients with preexisting liver diseases are likely at risk for severe coronavirus disease 2019 (COVID-19) and may be associated with poor outcomes.

Chapter 12. Antiviral Agents

This chapter discusses the agents with activity primarily against RNA viruses. The communicable diseases of the respiratory tract are probably the most common cause of symptomatic human infections. The viruses that are causative agents for human respiratory disease comprise the five taxonomically distinct families: orthomyxoviridae, paramyxoviridae, picornaviridae, coronaviridae, and adenoviridae. The influenza viruses, which consist of types A, B, and C, belong to the family orthomyxoviridae. Types A and B have been associated with significant increases in mortality during epidemics. The disease may be asymptomatic or cause symptoms ranging from the common cold to fatal pneumonia. Immunization against influenza has been recommended for high-risk groups and antiviral chemotherapy (amantadine) is available for the treatment and prophylaxis of all influenza A infections. There is both a great need for and interest in developing a chemotherapeutic agent for the treatment of these two viral, respiratory tract pathogens. The family picornaviridae contains the genus Rhinovirus that is composed of over a hundred distinct serotypes. Amantadine and rimantadine are specifically active against influenza A virus infections. The amantadine recipients reported a higher incidence of side effects largely attributed to the central nervous system (CNS) symptoms. This difference in side effects may be a pharmacokinetic phenomenon that results in higher plasma concentrations of amantadine. Significant progress continues to be made in the clinical use and development of agents active against DNA viruses. Acyclovir (9-(2-h droxyethoxymethyl)guanine) has been the subject of several reviews and of a syrnposium. Considerable progress has been made in evaluating the clinical promise of acyclovir; however, there remains much to be learned concerning the best use of this drug in clinical practice. Significant strides have been made in the development of clinically useful antiviral agents, especially against the DNA viruses of the herpes family. Most of these agents are directed against viral nucleic acid synthesis and require activation by a virus-induced thymidine kinase. Researchers have begun to focus on other strategies that may produce broader spectrum anti-viral agents with different mechanisms of action.

Do we all face the same risk when bathing in the estuary?

With the development of coastal areas, microbial water quality is an emerging public health issue though few studies have focused on risks according to age. A survey was undertaken of faecal contamination in relation to recreational activities in the Peel Harvey estuarine system, Western Australia. Levels of exposure to contaminated water were estimated though social surveys. Follow-up was also conducted to estimate the incidence of disease associated with bathing in the estuary. Pathogen levels exceeded the guideline values recommended by the World Health Organisation (WHO) at most locations throughout the year. The social survey provided information about exposure of the population in age groups. Only 31% of the recreational users belonged to the healthy adult group upon which the WHO quantitative microbial risk assessment model is based. A correlation was established between microbial water quality and incidence of respiratory diseases for children as well as for adults. Exposure to recreational water increased the incidence of respiratory illnesses for the whole population almost by a factor 2. Behaviours which resulted in increased exposures were associated with increased incidence of illnesses were observed, particularly among children aged 11-15 yr, who exhibited the highest odd ratio (OR 4.23 [2.44-6.01], CI 95%, p=0.05). There is a need for combining epidemiology studies with risk assessment processes and complementing them with social surveys for understanding the risk of recreational activities to public health.

Doenças respiratórias agudas em serviços de saúde entre 1996 e 2001, Fortaleza, CE

OBJETIVO: As doenças respiratórias agudas, principalmente as pneumonias, são a causa mais importante de óbito em menores de cinco anos e são responsáveis por doença grave nos maiores de 60 anos. O estudo realizado tem como objetivo descrever as principais características epidemiológicas dos casos de doenças respiratórias agudas notificadas pelas unidades de saúde. MÉTODOS: Todos os registros de atendimentos de pacientes com doença respiratória aguda, no período entre 1996 e 2001, foram revistos semanalmente, em formulário específico, a partir dos boletins de atendimento médico preenchidos por 100 unidades públicas de saúde. Os dados foram classificados em não pneumonia e pneumonia por faixa etária. RESULTADOS: Foram informados 2.050.845 casos de doença respiratória aguda no período estudado. Os meses com maior número de casos foram maio e junho. A faixa etária mais acometida foi a de um a quatro anos, com cerca do dobro do número de casos das outras faixas etárias. Pneumonias representaram, aproximadamente, 7,7% dos casos. CONCLUSÕES: O acompanhamento das doenças respiratórias agudas serve para mostrar sua magnitude em termos numéricos, e estimular seu diagnóstico apropriado, tratamento precoce e prevenção, tanto das complicações, quanto de sua ocorrência.

Enteroviruses isolated from patients with acute respiratory infections during seven years in Rio de Janeiro (1985-1991)

Enteroviruses were investigated in respiratory secretions collected from patients with acute respiratory infections (ARI) over a seven year period (1985-1991), as part of a longitudinal study of ARI aetiology. All the viruses that are most commonly associated with ARI were found in this study. Among the virus isolates, enteroviruses were only less frequent than respiratory syncytial viruses, adenoviruses and influenzaviruses. Forty five enterovirus samples were isolated from patients with either upper respiratory tract infections (URTI) or lower respiratory tract infections (LRTI). From these enterovirus isolates, thirty one samples were identified as poliovirus (n = 18) and non polio enterovirus (n = 13) by serum neutralization. Poliovirus were identified as type 1 and 2 and all of them were vaccinal strains. From thirteen non polio enterovirus, twelve were identified as echovirus serotypes 1, 2, 7, 11, 19 and 31. The remainder was identified as coxsackievirus B4.

The spectrum of adult adenovirus pneumonia

Adenovirus pneumonia is endemic among infants and children. We report an adult case of adenovirus pneumonia causing respiratory failure and infection in the patient's spouse. The case in the spouse presented as an exacerbation of COPD.

Community-acquired pneumonia in older patients

OBJECTIVES

To document the prevalence of Legionella sp., Mycoplasma Pneumoniae and Influenza A and B in older patients hospitalized for community-acquired pneumonia (CAP) of nursing-home acquired pneumonia (NHAP) and to determine risk factors associated with fatal outcome or prolonged hospital stay.

DESIGN

Prospective clinical and serological study.

PATIENTS

All patients with CAP of NHAP--confirmed by chest roentgenogram--admitted to a 320-bed acute care geriatric university hospital from May 1, 1988 to August 31, 1989, were included. Serological testing was performed upon admission and after 2 and 4 weeks. Relevant data concerning medical history, clinical examination, and laboratory data were recorded upon admission. Ninety-nine patients (age: 85 +/- 6.3 years, 36 male, 63 female) met inclusion criteria; 20 came from nursing homes, 79 from their homes in the community.

MAIN RESULTS

Fourteen patients died during the month after admission. An etiological diagnosis could be established in 22 patients. No cases of Legionella pneumonia and one case of M. pneumoniae were detected. Seven patients had evidence of Influenza pneumonia. Nonsurvivors were more likely to have been admitted from a nursing home and to have a temperature less than 37.5 degrees C and elevated urea nitrogen (BUN). Cyanosis, involvement of upper lobes, elevated white blood cell counts, and higher percentage of band forms were associated statistically with longer treatment.

CONCLUSIONS

This study confirms the low prevalence of Legionella sp. and M. Pneumoniae infection in CAP and NHAP in this age group. Risk factors as to outcome and length of treatment may be used as points to identify high risk patients, with special attention to patients coming from nursing homes, and patients with high BUN.

Adult bacterial nasopharyngitis: a clinical entity?

OBJECTIVE

To investigate bacterial nasopharyngitis as a cause of adult upper respiratory infection.

DESIGN

Prospective case series.

SETTING

Walk-in medical clinic of a university hospital.

PATIENTS

507 patients with cold or flu symptoms, sore throat, or recent cough; 21 control subjects without symptoms of upper respiratory infection.

MEASUREMENTS AND MAIN RESULTS

After thorough history and physical examination, the patients underwent nasopharyngeal aspiration and throat culture. Nasopharyngeal specimens were cultured for both bacteria and viruses; antigens for influenza, parainfluenza, and respiratory syncytial virus were sought by enzyme-linked immunosorbent assay (ELISA); serum antibodies to viral respiratory pathogens were determined. Group A beta-hemolytic streptococci grew from the throat specimens of 39 of the 507 patients (8%) or 38 of 334 patients (11%) who had clinical diagnoses of pharyngitis. Thirty-three cases of influenza A, 20 cases of influenza B, and seven cases of parainfluenza infections were diagnosed. Bacteria were cultured from the nasopharyngeal secretions of 284 patients (56%). In contrast to pharyngeal culture, commensal mixed flora were rarely found in nasopharyngeal culture. Nasopharyngeal culture of bacteria usually considered to be respiratory pathogens was significantly associated with the presence of leukocytes. Streptococcus pneumoniae (odds ratio 6.0, 95% confidence interval 2.6-14.2), Moraxella catarrhalis (odds ratio 12.9, 95% confidence interval 3.1-79.5), and Hemophilus influenzae (odds ratio 3.0, 95% confidence interval 1.2-7.4) were all associated with the presence of leukocytes. In contrast, nasopharyngeal culture of coagulase-negative staphylococci, mixed flora, and the documentation of a viral infection were not associated with the presence of leukocytes. For none of 21 control subjects were "pathogenic" bacteria found.

CONCLUSIONS

These data suggest that potentially pathogenic bacteria may have a causal role in adult nasopharyngitis, although further data are needed to confirm this hypothesis.

Viral respiratory infections in the institutionalized elderly: clinical and epidemiologic findings

OBJECTIVE

To prospectively evaluate the incidence and impact of viral respiratory infection in the institutionalized elderly during a winter season.

DESIGN

Prospective descriptive study, without intervention.

METHOD

Patients with respiratory illnesses were evaluated by a directed history and physical examination. Nasopharyngeal secretions for viral culture were obtained, and acute and convalescent serum samples were obtained for analysis. Serologic evidence of infection with respiratory syncytial virus (RSV) and parainfluenza were determined by enzyme immunoassay (EIA), and influenza by hemagglutination-inhibition assay and EIA.

SETTING

A 591-bed nursing home.

PARTICIPANTS

Residents with signs or symptoms of acute respiratory illness (nasal congestion, pharyngitis, cough, wheezing, or respiratory difficulty) were eligible for study.

RESULTS

A viral etiology was documented in 62 out of 149 illnesses (42%). RSV was the most common virus associated with illness; it was documented in 27% of respiratory illnesses, followed by rhinovirus (9%), parainfluenza (6%), and influenza (1%). RSV was associated with significantly more severe disease when compared with rhinovirus. Clustering of specific viral infections occurred, suggesting nosocomial transmission.

CONCLUSIONS

Viruses are an important cause of acute respiratory infections in the institutionalized elderly during the winter months.

Aspirin-induced asthma as a viral disease

A hypothesis is presented which states that aspirin-induced asthma results from chronic viral infection. This type of asthma has, indeed, a highly characteristic clinical course, reminiscent of viral upper respiratory tract infection. It is suggested that, in response to a virus, a long time after the initial exposure, specific cytotoxic lymphocytes are produced. Their activity is suppressed by prostaglandin E2 (PGE2) produced by pulmonary alveolar macrophages. Anti-cyclo-oxygenase analgesics block PGE2 production, and allow cytotoxic lymphocytes to attack and kill their target cells, i.e. the virus-affected cells of the respiratory tract. During this reaction, toxic oxygen intermediates, lysosomal enzymes and mediators are released, which precipitate attacks of asthma. These acute attacks can be prevented by avoidance of all drugs with anti-cyclo-oxygenase activity, however, asthma continues to run a protracted course because of chronic viral infection.