An epidemic of a pertussis-like illness caused by Chlamydia pneumoniae

Resurgence of pertussis in Taiwan during 2009-2015 and its impact on infants

BACKGROUND/PURPOSE

Pertussis incidence markedly decreased due to universal vaccination, but outbreaks had been noted worldwide in recent decade. This study was conducted to know the epidemiology of pertussis and its impact on infants in Taiwan.

METHODS

Epidemiologic parameters for confirmed pertussis cases were collected from the Taiwan Centers for Disease Control. The incidence of each age group over years was calculated using population data. We also did retrospective reviews of laboratory-confirmed pertussis cases in NTUH to analyze clinical characteristics and disease severity.

RESULTS

A total of 668 confirmed pertussis cases were obtained from the Taiwan CDC open database between 2003 and 2017. There was higher incidence during the period 2009-2015, with a mean incidence of 0.27 cases per 100,000 population, about 2-fold increase compared with mean incidence of 0.12 cases per 100,000 population during the period 2003-2008. Infants accounted for the highest proportion of all cases (49.8%), with mean incidence of 16.1 cases per 100,000 people per year during 2009-2015, and a trend of increase was found from 2003 to 2015. In NTUH, a total of 17 laboratory-confirmed pertussis cases were diagnosed during 2012-2016, and 14 cases were young infants. Among them, 9 infants had been admitted to intensive care unit and 2 infant needed invasive ventilator support.

CONCLUSION

There was a resurgence of pertussis during 2009-2015 and it had significant impact on infants. Young infants with pertussis may be severe and need intensive care, so preventive strategy may be advocated for them.

Serological study of Bordetella Pertussis, Mycoplasma Pneumonia and Chlamydia Pneumonia in Iranian hajj pilgrims with prolonged cough illnesses: A follow-up study

INTRODUCTION

Hajj pilgrimage is the biggest and longest mass gathering in the Muslim world. Annually, about 50% of more than 2.5 million pilgrims participating in this ritual get involved in severe devastating coughs. Most coughs continue, so the pilgrims turn back home and transmit them to family members and other people. Despite the high prevalence of coughs for many years, what causes them remains unknown. Considering the pertussis-like clinical picture of the so-called "hajj coughs", the researchers conducted a study to measure antibodies against three known common atypical bacteria, namely Bordetella Pertussis, Chlamydia Pneumonia and Mycoplasma Pneumonia.

PATIENTS AND METHODS

The study was done on three out of eleven groups of pilgrims from Yazd province, central Iran. The sample was selected randomly and consisted of 202 pilgrims who completed an informed consent. Their blood samples were taken, and the plasma was separated and then stored at -70 °C. After turning back from the journey, the pilgrims had their second blood samples taken. As many as 52 pilgrims failed to come for the second sampling, and two samples were broken during transportation. The final analysis was performed on the remaining 148 pairs of samples.

RESULTS

Antibodies were already elevated in many pilgrims before the journey probably due to their old age (causing more exposure to pathogens) or unplanned pertussis vaccination. After their return, antibody elevation was only mild, again probably due to the old age of the participants (i.e. due to their weaker immune systems). Some antibodies even fell down without any known reason. In this study, previous hajj journey was assumed as a prophylactic factor, due to acquisition of immunity. Coughs with a prolonged pertussis-like picture were also presumed to be more related than other types of coughs to atypical pathogens. Statistical tests showed that the history of previous journeys had no prophylactic effect. Also, no correlation was found between the clinical pictures of coughs and infection with atypical bacteria.

CONCLUSION

Even though some rises and falls occurred in the antibodies titer, the variations could hardly be attributed to coughs in this study. Indeed, the variation of antibodies had no meaningful relationship with clinical factors. In this regard, further studies are needed to clarify the reason for the so-called "hajj coughs", but epidemiological studies will be difficult to do until easier and more reliable methods become available for accurate diagnosis.

Chlamydia pneumoniaeRespiratory Infections in Taiwan

To understand the epidemiology of Chlamydia pneumoniae acute infections in Taiwan, we collected 116 paired and 244 single sera from patients suspected of C. pneumoniae infection and conducted microimmunofluorescence test. Eighty-three patients (83/360, 23%) met the diagnostic criteria of current C. pneumoniae infection. The C. pneumoniae infections were significantly higher in men than in women (P< or =0.0001) and were most frequent in the group of 40-49 year-olds, and the people older than 70 years old. C. pneumoniae infection often occurred in the late autumn lasting to the cold winter and in the transition period between the spring and summer.

Acute primary Chlamydophila pneumoniae bronchitis and bronchial hyperresponsiveness in young nonasthmatic Thai military recruits

BACKGROUND

A correlation between chronic Chlamydophila pneumoniae infection and chronic airway diseases has been suggested by several studies, but direct evidence to support the link between acute Cpneumoniae infection and new-onset asthma is insufficient.

OBJECTIVES

To determine the association between C. pneumoniae infection and subsequent bronchial hyperresponsiveness (BHR) and hence asthma.

METHODS

We studied 110 Thai military conscripts during an epidemic of Cpneumoniae infection in Thailand, from November 1, 1998, through February 28, 1999. The diagnosis was based on a standardized microimmunofluorescence technique. Spirometry and methacholine challenge tests (MCTs) were conducted. This cohort study excluded all conscripts with preexisting positive MCTs.

RESULTS

Ninety-three percent of the conscripts presented with an acute cough of a mean duration of 15.2 days. The pattern of serologic response revealed that 83% had acute primary infections and 10% had acute reinfections. Mean forced expiratory volume in 1 second was 99.5%, with an improvement of 1.8% after bronchodilator administration. Only 3.6% revealed small airways disease (forced expiratory flow between 25% and 75% of <65%) on spirometry. Methacholine challenge tests failed to demonstrate BHR in all conscripts, and none had developed a new-onset wheeze (physician-diagnosed asthma) at up to 2 years of follow-up.

CONCLUSIONS

This study demonstrates that cough in patients with acute primary Cpneumoniae infection is not associated with BHR among previously healthy adults. The pathogenetic mechanism by which organisms cause coughing and wheezing in acute bronchitis seems to be different among causative respiratory pathogens.

Chlamydia pneumoniae infection after lung transplantation

BACKGROUND

Chlamydia pneumoniae is established as a common agent of acute respiratory tract infection and has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease. Airway disease is a prominent cause of morbidity and mortality after lung transplantation. We investigated the role of C pneumoniae as a pulmonary pathogen after lung transplantation.

METHODS

Eighty lung transplant recipients underwent 232 bronchoscopies with bronchoalveolar lavage with or without transbronchial lung biopsy during 1 year for surveillance of rejection and infection, or where clinically indicated.

RESULTS

C pneumoniae was detected using nested polymerase chain reaction in 9 of 36 (25%) recipients studied within 30 days of lung transplantation, 3 of whom remained positive on repeat lavage and died from airway disease in the first year post-operatively. By comparison, all 27 recipients with negative lavage survived >1 year. Lavage was positive for C pneumoniae in 18 of 71 (25%) recipients studied >30 days after lung transplantation, 5 of whom had pneumonia and 8 of whom had bronchiolitis obliterans syndrome. Eleven also had acute pulmonary allograft rejection.

CONCLUSIONS

Persistent infection with C pneumoniae (whether donor-derived, de novo or re-activated) appears deleterious to pulmonary allograft function and is associated with early mortality, rejection and bronchiolitis obliterans syndrome after lung transplantation. A trial of empiric antibiotic therapy for C pneumoniae may therefore be warranted in the attempt to prevent progressive inflammatory airway disease.

Outbreak of Chlamydophila pneumoniae infection in long-term care facilities and an affiliated hospital

This paper reports an outbreak of Chlamydophila pneumoniae infection in long-term care facilities and an affiliated hospital. The outbreak involved rapid spread of infection, and was inconsistent with several outbreaks experienced among younger populations. In addition, there were differences in the incidences among facilities and the affiliated hospital in relation to mean age. Our findings indicate that it is possible that elderly residents may be more susceptible to acquiring this infection. Physicians and other health care providers in long-term care facilities should consider C. pneumoniae in the differential diagnosis of an outbreak of respiratory infection.

Defining pertussis epidemiology: clinical, microbiologic and serologic perspectives

In the past decade, numerous sources have noted an increase in reported pertussis in highly immunized populations. This has been accompanied by a perceived change in disease epidemiology, characterized by a significant increase in reported pertussis incidence among adolescents and adults. In populations where children are routinely immunized, adolescents and adults now constitute the main source of infection in infants. However, a range of factors makes delineation of these epidemiologic trends difficult. Reported cases of pertussis represent only a fraction of the actual number of Bordetella pertussis symptomatic infections, because underconsulting, underrecognition and underdiagnosis are widespread and are a particular problem in adolescents and adults. Possible explanations for failure to diagnose pertussis include the heterogeneity in pertussis disease expression and low physician awareness and index of suspicion. Consequently defining pertussis from a clinical perspective is difficult, and this is reflected by a lack of consistency between case definitions. Although case definitions for specific circumstances have been established by the World Health Organization and the United States Centers for Disease Control, these are not universally useful, making intercountry comparisons and global evaluation difficult. Less-than-optimal and poorly performed laboratory tests, or their lack of availability, also make confirmation of B. pertussis infection difficult. To overcome these problems, clinical case definitions should be standardized for outbreak and endemic situations. Rapid, easy-to-use and inexpensive laboratory diagnostic techniques also must be made available and be widely implemented. In particular, polymerase chain reaction and single serum serology are 2 techniques that should be more widely adopted.

[Culture-confirmed whooping cough in a tertiary center over a twelve-year period]

OBJECTIVE

To study the characteristics of patients diagnosed with whooping cough at a tertiary center in Barcelona, Spain.

MATERIAL AND METHODS

We performed a retrospective study of patients aged less than 18 years treated for pertussis-like cough or clinically-suspected whooping cough over a 12-year period (1989-2000). Only patients with isolated Bordetella spp. were included. The variables of age, sex, vaccination status, hospitalization, clinical manifestations, severity, and lethality were analyzed.

RESULTS

One hundred sixty-one patients with positive Bordetella spp. culture were identified. Of these, complete information was available in 149 (79 boys and 70 girls) with a median age of 3 months (range: 13 days-17 years); 77.2 % were aged 6 months or less. All the isolated strains corresponded to B. pertussis except three that corresponded to B. parapertussis. Three epidemic cycles (in 1989, 1992 and 2000) were observed during the study period. A total of 72.5 % of cases occurred between May and September. Bordetella spp. was associated with other bacteria in 28.2 % of the patients, viruses in 13.4 % and a bacterium and a virus in 4.7 %. One hundred twenty-one patients required hospitalization, of which 14.9 % were admitted to the intensive care unit. Age was the only factor associated with risk for hospitalization, which was more frequent in younger infants (p < 0.0001). Paroxysmal cough with cyanosis was present in 53.4 % of the patients, leucocytosis with lymphocytosis occurred in 67.5 % and apneas were present in 21.5 %. Chest X-ray revealed atelectasis in 34.1 %. The mean length of hospital stay was 11 days (range: 1-70 days). Three boys aged less than 3 months with malignant pertussis syndrome died (lethality: 2 %). More than half the patients (59.7 %) were not vaccinated (55.4 % for being under the age of 3 months) and only 16 % had received three or more vaccination doses.

CONCLUSIONS

Whooping cough continues to be a severe disease in infants, with a high admission rate during the first 6 months of life. New preventive strategies are required to protect infants who have not yet developed full immunity to this infection.

Mycoplasma pneumoniae and Chlamydia pneumoniae cause lower respiratory tract disease in paediatric patients

New studies suggest that Mycoplasma pneumoniae and Chlamydia pneumoniae play a more significant role as causes of lower respiratory tract infections in childhood than was previously thought. In particular, the incidence of infections caused by these pathogens is high in children aged less than 5 years, the infections themselves seem to be a possible cause of wheezing, and may present a more complicated course when not treated with adequate antimicrobial agents. However, despite the increasing pathogenic significance of M. pneumoniae and C. pneumoniae, progress in fighting them is hampered by the lack of rapid and standardized diagnostic methods. This not only makes it practically impossible for practitioners to make a specific microbiological diagnosis, but has also had an adverse effect on treatment trials and has generated some questionable results. Carefully randomized and controlled trials are clearly needed to examine the effectiveness of different antibiotics against M. pneumoniae or C. pneumoniae and the optimal duration of therapy in various patient populations.

Emerging role of Mycoplasma pneumoniae and Chlamydia pneumoniae in paediatric respiratory-tract infections

Increased use of specialised diagnostic techniques over the past 10 years has allowed considerable new information to be obtained concerning Mycoplasma pneumoniae and Chlamydia pneumoniae infections. In children, these pathogens seem to have a more important role in causing respiratory-tract infections than previously thought; they have been associated with wheezing, and they are also frequent in children aged under 5 years. Contrary to original belief, no clinical, laboratory, or radiological findings seem to be unique to M. pneumoniae or C. pneumoniae; furthermore, there is no rapid and cost-effective diagnostic test capable of identifying these pathogens. Appropriate antimicrobial treatment of the infections they cause is needed to reduce the recurrent episodes of wheezing and other respiratory symptoms, to decrease morbidity, and to avoid the spread of the pathogens. However, a number of therapeutic issues remain unsolved.

A preliminary evaluation of a new enzyme immunoassay to detect Chlamydia pneumoniae-specific antibodies

New enzyme immunoassays (EIAs) for determination of specific IgG, IgA, and IgM antibody titers to Chlamydia pneumoniae were evaluated independently in three research laboratories. Specificity of the EIAs was enhanced by removing LPS from the chlamydial antigen. The performance of these EIAs was evaluated in comparison with the microimmunofluorescence (MIF) test using specimens from: (i) a group of adult patients with community-acquired pneumonia (CAP) previously diagnosed as having an acute chlamydial infection by the complement fixation test or the whole inclusion fluorescence test; (ii) from a group of adult patients with acute respiratory tract infections; and (iii) from a group of young children consecutively presenting with acute respiratory tract infections. The MIF test and the EIAs detected acute infections in paired serum specimens from 12 of 14 patients from the first group. Eleven of these 12 patients were positive in both tests. The MIF test detected seven acute infections in single convalescence serum specimens from eight patients. Two of these were also positive in the EIAs. Paired serum specimens from the second group of adult patients (n=12) were collected during an epidemic of C. pneumoniae. The EIAs detected six acute infections. The MIF test detected two additional patients with acute infections. From the group of young children (n=30), the EIAs detected two patients with acute infections. Our conclusion from this preliminary evaluation is that these EIAs could be useful for laboratory diagnosis of acute C. pneumoniae infections. Comprehensive prospective studies should provide suitable data to calculate the sensitivity, specificity, and predictive values.

Chlamydia pneumoniae respiratory infections

Chlamydia pneumoniae is a significant cause of both upper and lower respiratory tract infections. The spectrum of diseases ranges from asymptomatic infection to serious disease, including severe pneumonia and exacerbations of chronic bronchitis requiring mechanical ventilation. There is increasing evidence of involvement of C. pneumoniae infection in bronchial asthma, and the role of this agent in immunocompromised patients has also begun to be appreciated.

Fever without apparent source on clinical examination, lower respiratory infections in children, and enterovirus infections

This section focuses on issues in infectious disease that are commonly encountered in pediatric office practice. McCarthy discusses recent literature regarding the evaluation and management of acute fevers without apparent source on clinical examination in infants and children and the evaluation of children with prolonged fevers of unknown origin. Klig reviews recent literature about lower respiratory tract infection in children. Finally, Kennedy and Kahn discuss recent developments in infectious diseases pertinent to office practice.