Defining pertussis epidemiology: clinical, microbiologic and serologic perspectives

Bordetella pertussis targets the basolateral membrane of polarized respiratory epithelial cells, gets internalized, and survives in intracellular locations

The airway epithelial barrier is a continuous highly organized cell layer that separates the exterior from the underlying mucosal tissue, preventing pathogen invasion. Several respiratory pathogens have evolved mechanisms to compromise this barrier, invade and even reside alive within the epithelium. Bordetella pertussis is a persistent pathogen that infects the human airway epithelium, causing whooping cough. Previous studies have shown that B. pertussis survives inside phagocytic and nonphagocytic cells, suggesting that there might be an intracellular stage involved in the bacterial infectious process and/or in the pathogen persistence inside the host. In this study we found evidence that B. pertussis is able to survive inside respiratory epithelial cells. According to our results, this pathogen preferentially attaches near or on top of the tight junctions in polarized human bronchial epithelial cells and disrupts these structures in an adenylate cyclase-dependent manner, exposing their basolateral membrane. We further found that the bacterial internalization is significantly higher in cells exposing this membrane compared with cells only exposing the apical membrane. Once internalized, B. pertussis mainly remains in nondegradative phagosomes with access to nutrients. Taken together, these results point at the respiratory epithelial cells as a potential niche of persistence.

Seroepidemiology of pertussis in the east of China: Estimates of incidence of infection in adolescents and adults pre- and post-COVID-19

Introduction

The dramatic decrease in the number of reported cases of pertussis during COVID-19 pandemic has been underestimated. The objective was to compare the estimated incidence rate of pertussis in populations pre- and post-COVID-19 pandemic by analyzing the anti-pertussis toxin (anti-PT) IgG and anti-filamentous hemagglutininant (anti-FHA) IgG antibodies in healthy Chinese population from 2018 to 2021.

Methods

All serum samples (N = 1,000) were collected from healthy population (aged ≥ 15 years) who attended an annual monitoring project of antibody levels in Jiangsu province in 2018-2021 were measured by ELISA.

Results

The positive rates of anti-PT IgG and anti-FHA IgG antibodies were 11.4% (114/1,000) and 20.2% (202/1,000) (≥40 IU/ml), the GMC were 17.25 (95% CI: 15.49-19.03) IU/mL and 24.94 (95% CI: 22.73-27.16) IU/mL in the study population, respectively. The percentage of participants with anti-PT IgG antibodies higher than 40 IU/mL was 5.20% (11/212) in 2018, 5.5% (19/348) in 2019, 21.2% (46/217) in 2020 and 17.0% (38/223) in 2021, respectively. The non-detectable rate (<5 IU/mL) of anti-PT IgG antibodies was 16.9, 17.7, 28.1, and 37.3% in 2018, 2019, 2020, and 2021, respectively. We assumed that the infection occurred within 58.6 days, and based on the overall proportion (2.9%) of individuals with anti-PT IgG antibody ≥100 IU/ml, the incidence rate (/100) was estimated by the formula to be 18.08 (95% CI: 12.40-26.11). In addition, the estimated incidence of Post-COVID-19 was higher than that of Pre-COVID-19 (36.33/100 vs. 12.84/100), and the difference was statistically significant (p < 0.05).

Conclusions

Our results suggest a high rate of under-reporting of pertussis in Jiangsu Province both pre- and post-COVID-19 pandemic, and there are a large number of adults of childbearing age who are susceptible to pertussis. It seems imperative that vaccination of adolescents and adults should be considered for inclusion in vaccination programs.

Childhood pertussis is still here: An Asian city's perspectives

INTRODUCTION

Pertussis, or whooping cough, is a highly contagious respiratory infection that is caused by the bacterium Bordetella pertussis. It is one of the most common causes of death in childhood. It is also a frequent cause of chronic cough in children, adolescents, and adults.

METHODS

Global and Hong Kong perspectives of childhood pertussis were described.

RESULTS

Hong Kong has prided herself in the city's childhood immunization program. There appear to be no major outbreaks of pertussis since the 1960s. Nevertheless, pediatricians may see isolated cases of pertussis or pertussis-like cases from time to time. Occasionally, infants are severely affected with apneas and managed with ventilator supports in the PICU. Outbreaks of the notifiable disease continue to occur despite a reasonable surveillance system and vaccination program in Hong Kong. Vaccination of mothers, adolescents, and adults are efficacious methods to further reduce the risks of pertussis. Macrolides remain efficacious antibiotics especially used early during the infectious phase. Infants with pertussis may require intensive care support and morbidity is high.

CONCLUSIONS

Physicians should be reminded from time to time that outbreaks of pertussis still exist in Hong Kong and in many cities globally.

Loop-Mediated Isothermal Amplification Coupled With Nanoparticle-Based Lateral Biosensor for Rapid, Sensitive, and Specific Detection of Bordetella pertussis

Bordetella pertussis is the most frequent causative agent for pertussis, which is a highly contagious disease. Here, we developed a method based on loop-mediated isothermal amplification (LAMP) and nanoparticle-based lateral flow biosensor (LFB) for the timely diagnosis of B. pertussis infections. A set of six primers was designed for LAMP reactions, and the LAMP results were rapidly and visually indicated using LFB. The recommended condition for the B. pertussis LAMP reactions is 40 min at 66°C. Our results confirmed that the LAMP-LFB assay could specifically detect B. pertussis and did not cross-react with non-B. pertussis isolates. The sensitivity of the B. pertussis LAMP-LFB assay was 50 fg per reaction. In particular, 108 nasopharyngeal swab (NPS) samples were collected to evaluate the B. pertussis LAMP-LFB assay, and the results were compared with those of the quantitative PCR (qPCR) method. The positive rates of B. pertussis LAMP-LFB and qPCR were 40.7% and 38.8%, respectively, and the agreement between the LAMP-LFB and qPCR results was 98%, with a kappa value of 0.96. The whole process of LAMP-LFB can be completed within 1 h, which is much shorter than that of qPCR, including about 15 min of rapid DNA extraction, 40 min of LAMP reaction, and within 2 min of the LFB test. Collectively, the B. pertussis LAMP-LFB assay developed in this report offers a new option for the rapid, reliable, and simple diagnosis of B. pertussis infections.

Analysis of antibiotic sensitivity and resistance genes of Bordetella pertussis in Chinese children

OBJECTIVE

To understood the pathogen detection status and clinical characteristics of suspected pertussis in children and to observe the drug sensitivity and drug resistance genes of Bordetella pertussis (B. pertussis).

METHODS

Three hundred fifty-one cases were collected and their nasopharyngeal swab samples were analyzed by culture and fluorescent quantitative polymerase chain reaction. The susceptibility to erythromycin, clindamycin, ampicillin, levofloxacin, and sulfamethoxazole-trimethoprim were tested by E-test for the positive strains, and the susceptibility to erythromycin was also tested for the KB disk diffusion method. The 23S rRNA gene of the positive strains was amplified and sequenced, and statistical analysis was performed in conjunction with clinical data.

RESULTS

The positive rate of bacterial culture was 16.8% (59/351), and the positive rate of PCR was 62.4% (219/351). Two cases were positive about bacterial culture and negative for PCR. There were 221 confirmed cases of pertussis. The E-test results showed that the rate of the sensitivity of the 55 strains of pertussis to erythromycin and clindamycin was 50.9% (28/55), the minimum antibiotic concentration50 (MIC50) and MIC90 values were 0.094/>256 and 0.75/>256 mg/L, respectively, and the MIC50/MIC90 to ampicillin, levofloxacin, and sulfamethoxazole were 0.125/0.19, 0.38/0.5, and 0.125/0.25 mg/L, respectively. The KB disk diffusion method showed 27 of the 55 strains 49.1% (27/55) was resistant to erythromycin; all of the resistant strains had the 23S rRNA gene A2047G mutation, and their MIC of erythromycin was >256 mg/L.

CONCLUSION

The diagnosis of pertussis by a fluorescent quantitative polymerase chain reaction method is more sensitive than that of bacterial culture. The resistance of B. pertussis to erythromycin was prominent. All of the strains of B. pertussis resistant to erythromycin in our center had the A2047G mutation of the 23S rRNA gene.

Asymptomatic Infection and Transmission of Pertussis in Households: A Systematic Review

We conducted a systematic review to describe the frequency of mild, atypical, and asymptomatic infection among household contacts of pertussis cases and to explore the published literature for evidence of asymptomatic transmission. We included studies that obtained and tested laboratory specimens from household contacts regardless of symptom presentation and reported the proportion of cases with typical, mild/atypical, or asymptomatic infection. After screening 6789 articles, we included 26 studies. Fourteen studies reported household contacts with mild/atypical pertussis. These comprised up to 46.2% of all contacts tested. Twenty-four studies reported asymptomatic contacts with laboratory-confirmed pertussis, comprising up to 55.6% of those tested. Seven studies presented evidence consistent with asymptomatic pertussis transmission between household contacts. Our results demonstrate a high prevalence of subclinical infection in household contacts of pertussis cases, which may play a substantial role in the ongoing transmission of disease. Our review reveals a gap in our understanding of pertussis transmission.

[Serological diagnosis of pertussis in older persons.]

The aim of the work was to assess the effectiveness of serodiagnosis of pertussis in people over 50 who complained of prolonged cough. The study included 30 patients over the age of 50 who applied to the consultative diagnostic center complaining of a prolonged cough in the period from 2015 - 2020. Blood serum samples were investigated in enzyme immunoassay with the definition of antitussive antibodies of three classes - IgM, IgG, IgA in the commercial test system RIDASCREEN (R-Biopharm AG, Germany). It was found that in the serum samples of individuals over the age of 50, IgM antibodies above the threshold level were not detected. Patients were divided into two groups - with IgG and IgA antibodies above the threshold level (group 1) and below the threshold level (group 2). In the first group, in 83.3% and 61.1% of patients, the levels of antibodies of the IgG and IgA class significantly exceeded the threshold level (189.8 ± 16.7 U / ml and 290 ± 20 U / ml, respectively), which indicated a pertussis infection; in 5.6% and 38.9% of patients, IgG and IgA class antibodies slightly exceeded the threshold level (20 U / ml and 43 ± 2.3 U / ml, respectively), which indicated a dying infection. In the second group, in 100% of patients, antibodies of the IgM and IgA classes were determined below threshold levels, and IgG antibodies were detected in 58.3% of individuals at low rates, which corresponded to the natural immunological background of individuals not infected with pertussis pathogen. Therefore, in the presence of a prolonged cough in adults, it is advisable to study blood serum samples for the presence of antitussive antibodies of three classes, which is especially important when people of older age live in families with young children and pregnant women.

Tracheal colonization factor A (TcfA) is a biomarker for rapid and specific detection of Bordetella pertussis

Pertussis is a highly contagious disease for which prompt, point-of-care diagnosis remains an unmet clinical need. Results from conventional test modalities (nucleic acid detection, serology, and culture) take hours to days. To overcome this challenge, we identified a new biomarker (tracheal colonization factor A, TcfA) for detection of Bordetella pertussis infection by lateral flow immunoassay (LFIA). We developed a library of 28 epitope-mapped monoclonal antibodies against TcfA and incorporated three antibodies into a LFIA. The LFIA did not cross-react with common bacterial or fungal organisms, but did react with nine distinct B. pertussis strains. The minimal linear epitope sequences targeted by the LFIA were conserved in 98% of 954 B. pertussis isolates collected across 12 countries from 1949–2017. The LFIA’s limit of detection was 3.0 × 10⁵ CFU/mL with B. pertussis cells in buffer, 6.2 × 10⁵ CFU/mL with nasopharyngeal washes from a non-human primate model, and 2.3 ng/mL with recombinant TcfA. The LFIA reacted with patient nasopharyngeal swab specimens containing as few as 1.8 × 10⁶B. pertussis genomes/mL and showed no false-positives. Rapid (< 20 min) LFIA detection of TcfA as a biomarker for B. pertussis infection is feasible and may facilitate early detection of pertussis.

Diagnostic limitations of clinical case definitions of pertussis in infants and children with severe lower respiratory tract infection

INTRODUCTION

Diagnosis of pertussis is challenging especially in infants. Most low and middle-income countries (LMIC) lack resources for laboratory confirmation, relying largely on clinical diagnosis alone for both case management and surveillance. This necessitates robust clinical case definitions.

OBJECTIVES

This study assesses the accuracy of clinical case definitions with and without lymphocytosis in diagnosing pertussis in children with severe lower respiratory tract infection (LRTI) in a LMIC setting.

METHODS

Children hospitalized with severe LRTI in a South African hospital were prospectively enrolled and evaluated for pertussis using PCR on respiratory samples. Clinical signs and differential white cell counts were recorded. Sensitivity and specificity of pertussis clinical diagnosis using WHO and Global Pertussis Initiative (GPI) criteria; and with addition of lymphocytosis were assessed with PCR as the reference standard.

RESULTS

458 children <10 years were enrolled. Bordetella pertussis infection was confirmed in 32 (7.0%). For WHO criteria, sensitivity was 78.1% (95% CI 60.7-89.2%) and specificity 15.5% (95% CI 12.4-19.3%); for GPI sensitivity was 34.4% (95% CI 20.1-52.1) and specificity 64.8% (95% CI 60.1-69.2%). Area under the curve (AUC) on receiver operating character (ROC) analysis was 0.58 (95% CI 0.46-0.70 for WHO criteria, and 0.72 (95% CI 0.56-0.88) for GPI with highest likelihood ratios of 5.33 and 4.42 respectively. Diagnostic accuracy was highest between five and seven days of symptoms for both criteria. Lymphocytosis had sensitivity of 31.3% (95% CI 17.5-49.3%) and specificity of 70.7% (95% CI 66.1-74.8%) and showed a marginal impact on improving clinical criteria.

CONCLUSION

Clinical criteria lack accuracy for diagnosis and surveillance of pertussis. Non-outbreak settings should consider shorter durations in clinical criteria. New recommendations still fall short of what is required for a viable clinical screening test which means the need to improve access to laboratory diagnostic support remains crucial.

Association of weather variability with resurging pertussis infections among different age groups: A non-linear approach

Pertussis has resurged in many countries over recent years, especially among adolescents and adults. This study assessed the effect of weather variability on resurging pertussis among different age groups in Jinan, China. Data on weekly pertussis notifications by age group and weather factors (mean temperature (MeanT), mean temperature standard deviation within a week (MeanT SD), diurnal temperature range (DTR) and relative humidity (RH)) were collected between 2013 and 2017. Distributed lag non-linear models (DLNMs) and regression tree models were used to examine the non-linear association between weather variability and pertussis infections. The 2-weeks cumulative relative risk (RR) of pertussis infections was 4.46 (95% confidence interval (CI): 2.33-9.51) in 0-4 age group, 6.25 (95% CI: 1.38-22.76) in 5-9 age group and 10.11 (95% CI: 2.83-39.07) in 10+ age group when MeanT was at 30.0 °C. MeanT SD (RR range in the three age groups: 2.82-5.83), DTR (RR range: 6.33-11.56) and RH (RR range: 2.02-7.43) also exert significant influence, with the highest risks at 10+ age group. Regression tree models showed the interactive effects of weather variability. The mean pertussis infections increased by over 1.7-fold in 0-4 years group when MeanT ≥14 °C, RH ≥57% and DTR ≥10 °C; by over 2.3-fold in 5-9 years group when MeanT ≥20 °C and MeanT SD ≥3 °C; by 2.0-fold in 10+ years group when MeanT ≥0.7 °C, DTR ≥8.3 °C and RH ≥74%. The study found significantly different associations between weather variability and pertussis infections by age group, and appeared to be stronger in 10+ years group. Continuing climate change, together with other risk factors such as low antibody levels among adolescents and adults, may facilitate pertussis resurgence. This supports previous suggestions of carefully reconsidering current vaccination programme to effectively curb the resurgence of pertussis.

Human bocavirus in children hospitalized for acute respiratory tract infection in Rome

BACKGROUND

The role of human bocavirus (HBoV) as a respiratory pathogen has not been fulfilled yet. We aimed to describe clinical and serological characteristics of children with HBoV hospitalized for acute respiratory tract infection and to evaluate whether differences occur between HBoV alone and in co-infection.

METHODS

We retrospectively reviewed data from 60 children (median age of 6.2 months, range 0.6-70.9) hospitalized for acute respiratory symptoms, with HBoV detected from a respiratory sample, using a reverse transcriptase-PCR for 14 respiratory viruses (including respiratory syncytial virus (RSV), influenza virus A and B, human coronavirus OC43, 229E, NL-63 and HUK1, adenovirus, rhinovirus, parainfluenza virus1-3, and human metapneumovirus).

RESULTS

HBoV was detected alone in 29 (48.3%) patients, while in co-infection with other viruses in 31 patients (51.7%), with a peak between December and January. Among the 60 patients, 34 were bronchiolitis, 19 wheezing, 3 pneumonia, 2 upper respiratory tract infection, and 2 whooping cough. Seven children (11.6%) required admission to the paediatric intensive care unit (PICU) for respiratory failure. No differences was observed in age, family history for atopy and/or asthma, clinical presentations, chest X-ray, or laboratory findings in children with HBoV alone vs. multiple viral detection. RSV was the most frequently co-detected virus (61.3%). When compared with HBoV detection alone, the co-detection of RSV and HBoV was associated with male sex (P = 0.013), younger age (P = 0.01), and lower blood neutrophil count (P = 0.032).

CONCLUSIONS

HBoV can be detected alone and in co-infection respiratory samples of children with an acute respiratory tract infection. A cause-effect relationship between HBoV and respiratory infection is not clear, so further studies are needed to clarify this point.

Neonatal Pertussis, an Under-Recognized Health Burden and Rationale for Maternal Immunization: A Systematic Review of South and South-East Asian Countries

Pertussis is an under-recognized cause of neonatal morbidity and mortality. To review information on the epidemiology and disease burden of neonatal pertussis in South and Southeast Asian countries, a systematic literature review of three bibliographic databases was undertaken. Peer-reviewed original studies on neonatal pertussis epidemiology and burden published since 2000, with a geographical scope limited to South and Southeast Asian countries, were included. Data were systematically extracted based on parameters defined a priori. Our findings show that the burden of neonatal pertussis and its complications is substantial. An increase in the number of pertussis cases has been noted since early 2000, ranging from 61 to 92.9% in infants 0-3 months old. The most common symptoms an infant is likely to present with are cough with or without paroxysms, cyanosis, apnea, tachypnea, difficulty in breathing and leukocytosis. In addition, it can lead to hospitalization (length of stay: 5-7 days), complications (e.g., pneumonia, seizures) and mortality ranging from 5.6 to 14.7%. Other observations indicate that diagnosis is challenging because of non-specific clinical symptoms. Specifically, for obstetricians and gynecologists, the information available for making informed decisions on the prevention of neonatal pertussis is unreliable. Maternal immunization against pertussis during late stages of pregnancy has proven to be efficacious and well tolerated. A high burden of neonatal pertussis, as well as its complications, is observed in South and Southeast Asian countries. There is a need to intensify efforts to protect this vulnerable population with maternal vaccination.Funding: GlaxoSmithKline Biologicals SAPlain Language Summary: Plain language summary available for this article. Please see Fig. 1 and the following link: https://doi.org/10.6084/m9.figshare.7951187 .

Rapid and Accurate Diagnosis of the Respiratory Disease Pertussis on a Point-of-Care Biochip

BACKGROUND

Pertussis is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis (B. pertussis). The infection is difficult to diagnose especially in underserved or resource-limited areas. We developed a low-cost and instrument-free diagnostic method for rapid and accurate detection of B. pertussis on a point-of-care (POC) testing device.

METHODS

We developed a paper/polymer hybrid microfluidic biochip integrated with loop-mediated isothermal amplification (LAMP) method for the rapid and accurate detection of B. pertussis. This microfluidic approach was validated by testing 100 de-identified remnant clinical nasopharyngeal swabs and aspirates, which were confirmed to be either positive or negative for B. pertussis by a validated real-time PCR assay at the Children's Hospital Los Angeles.

FINDINGS

The instrument-free detection results could be successfully read by the naked eye within 45 min with a limit of detection (LOD) of 5 DNA copies per well. Our optimized bacterial lysis protocol allowed the direct testing of clinical samples without any complicated sample processing/preparation (i.e. DNA extraction) or the use of any equipment (e.g. centrifuges). The validation of the microfluidic approach was accomplished by testing 100 clinical samples. High sensitivity (100%) and specificity (96%) with respect to real-time PCR were achieved.

INTERPRETATION

This microfluidic biochip shows great potential for point-of-care disease diagnosis in various venues including schools and physician's offices, especially in low-resource settings in developing nations.

FUNDING

NIH/NIAID under award number R21AI107415, NIH RCMI Pilot Grant, the Philadelphia Foundation, the Medical Center of the Americas Foundation.

Acute exacerbation of idiopathic pulmonary fibrosis induced by pertussis: the first case report

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is a severe condition with limited treatment strategies. Although respiratory infection is a major cause of AE-IPF, no reports have indicated pertussis infection as a cause. Here we report two cases of pertussis infection-induced AE-IPF.

CASE PRESENTATION

Both patients presented with a chief complaint of acute respiratory distress and were previously diagnosed with idiopathic pulmonary fibrosis (IPF). Neither patient had received any pertussis vaccination since adolescence. Both patients were diagnosed with AE-IPF accompanying acute pertussis infection based on chest computed tomography and serum pertussis toxin antibody > 100 EU/mL. Both patients were treated with macrolide antibiotics and systemic corticosteroids. Both patients were able to be discharged and return home.

CONCLUSIONS

The presence of pertussis infection in AE-IPF can present a diagnostic challenge, as coughing accompanying pertussis may be difficult to distinguish from IPF-associated coughing. Pertussis infection should be assayed in AE-IPF patients. Since pertussis can be prevented with vaccination and is expected to be affected by antibiotics, consideration of pertussis infection as a causative virulent factor of AE-IPF may be important for management of subjects with IPF.

Systematic review and meta-analysis of pertussis epidemiology in Latin America and the Caribbean: 1980-2015

OBJECTIVES

In Latin America and the Caribbean (LAC), pertussis disease incidence has reportedly increased since 2000 despite high vaccine coverage. A systematic review of pertussis literature and a meta-analysis was conducted to understand the burden of disease in LAC.

METHODS

A systematic literature review was completed, using relevant search terms. Original articles describing pertussis epidemiology and vaccine coverage in LAC published between 1980 and 2015 were identified. Applying a Bayesian meta-analysis random-effects model, we calculated pooled estimates and corresponding 95% credible intervals (95% CrIs) for pertussis incidence, case fatality ratio (CFR), pertussis prevalence among contacts, and coverage with three doses of diphtheria, tetanus, and pertussis (DTP) vaccine (DTP3).

RESULTS

A total of 59 studies meeting our selection criteria were identified, representing 15 countries. Of the 59, 15 of them provided incidence data, with 7 of the 15 reporting a pertussis case definition. The pertussis incidence estimate for the 1980-1999 period was 17.8 cases per 100 000 persons (95% CrI: 5.9-29.7); for the 2000-2015 period, it was 2.5 cases per 100 000 persons (95% CrI: 1.8-3.2). For the 1980-2015 period, the CFR, in 19 studies reviewed, was 3.9% (95% CrI: 2.9%-4.9%); for that same period, in 5 studies reviewed, pertussis prevalence among contacts was 24.9% (95% CrI: 13.7%-36.1%). Pooled DTP3 vaccine coverage estimates, in a total of 20 studies reviewed for the following three time periods, were: 1980-1990, 72.4% (95% CrI: 64.6%-80.2%); 1991-2000, 79.0% (95% CrI: 66.1%-91.9%); and 2001-2015, 90.0% (95% CrI: 87.7%-92.3%).

CONCLUSION

A decrease in pertussis incidence and an achievement of moderately high DTP3 vaccine coverage since the early 2000s was observed. The review highlights the need for increased publication of pertussis data at the country level and for LAC as a whole in order to better understand the true burden of the disease. Application of a standardized case definition and use of active case finding would aid in obtaining more accurate estimates of the disease burden in LAC.

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.

Block V RTX Domain of Adenylate Cyclase from Bordetella pertussis: A Conformationally Dynamic Scaffold for Protein Engineering Applications

The isolated Block V repeats-in-toxin (RTX) peptide domain of adenylate cyclase (CyaA) from Bordetella pertussis reversibly folds into a β-roll secondary structure upon calcium binding. In this review, we discuss how the conformationally dynamic nature of the peptide is being engineered and employed as a switching mechanism to mediate different protein functions and protein-protein interactions. The peptide has been used as a scaffold for diverse applications including: a precipitation tag for bioseparations, a cross-linking domain for protein hydrogel formation and as an alternative scaffold for biomolecular recognition applications. Proteins and peptides such as the RTX domains that exhibit natural stimulus-responsive behavior are valuable building blocks for emerging synthetic biology applications.

Epidemiology of pertussis in Casablanca (Morocco): contribution of conventional and molecular diagnosis tools

Background

Pertussis, a vaccine preventable disease, is still responsible of significant morbidity and mortality around the world, mostly in newborns. The aim of the present study was (1) to introduce pertussis surveillance in the major pediatric hospital of Casablanca (2) to analyze the prevalence of pertussis among children under 14 years of age and their entourage in Casablanca, Morocco.

Methods

This is a prospective and non-case controlled study, including children suspected of Pertussis admitted at the Abderrahim Harouchi Pediatric Hospital in Casablanca, from January 2013 to June 2015. Nasopharyngeal samples were obtained for Bordetella spp. culture and Real time PCR detection (RT-PCR) with specific primers of Bordetella spp., B. pertussis, B. parapertussis and B. holmesii. The detection of Bordetella spp. was also performed in some household contacts of the children suspected of pertussis.

Results

During the 2.5-years period, a total of 282 samples were collected from hospitalized children (156) and in some of their contacts (126). Among 156 samples from the children (from whom 57% were under 2 month of age), Bordetella DNA was detected in 61% (96/156) by RT-PCR. Among these positive samples, 91.7% (88/96) corresponded to B. pertussis DNA. Furthermore, in 39.5% (38/96) of the Bordetella positive samples, B. holmesii DNA was also detected. B. parapertussis DNA was detected in only one sample (1/156). Out of the 156 samples collected from the hospitalized children, only 48 were tested by culture, and 4 B. pertussis were isolated (8.3%). Among the 126 samples from the contacts of the children, mostly mothers (115 cases), Bordetella DNA was detected in 47% (59/126), 90% (53/59) being B. pertussis DNA. Moreover, B. holmesii DNA was also detected in 18.6% (11/59) of the Bordetella positive samples, and coexistence of B. pertussis and B. holmesii DNA in 36.5% (35/96). Two B. pertussis were isolated by culture performed on 43 samples of the contacts of the children (4.6%).

Conclusions

This study highlights the circulation of B. pertussis but also of B. holmesii in Casablanca-Morocco with a high proportion of co-infections B. holmesii/B. pertussis in infants and their mothers, indicate that infection of non-vaccinated infants could be more associated with young parents. Moreover, the RT- PCR provides a sensitive and specific diagnosis of B. pertussis infections and distinguishes it from other Bordetella species, and is therefore suitable for implementation in the diagnostic laboratory.

Pertussis outbreak in Polish shooters with adverse event analysis

In addition to different injuries, infections are the most common reason for giving up training altogether or reducing its volume and intensity, as well as a lack of opportunities to participate in sports competitions. Nowadays, a slow but constant re-emergence of pertussis, especially among teenagers and young adults, including athletes, can be observed. This paper describes an outbreak of pertussis among professional Polish shooters, focusing on the transmission of Bordetella pertussis infection between members of the national team, its influence on performance capacity and adverse event analysis. From 9 June, 2015 to 31 July, 2015, a total of 4 confirmed and suspected cases of pertussis were reported among members of the Polish Sport Shooting National Team, their relatives and acquaintances. Pertussis significantly decreased exercise performance of the first athlete, a 35-year-old woman, interrupted her training, and finally resulted in failure to win a medal or quota place. Pertussis also significantly decreased performance of the second athlete, a 25-year-old shooter. The other cases emerged in their families. Whooping cough is a real threat to athletes and should be prevented. Preventive measures include appropriate immunization, constant medical supervision, as well as early isolation, diagnostic tests and treatment of all infected sport team members. Regular administration of booster doses of the acellular pertussis vaccine (Tdpa) every 5 years seems reasonable.

[Clinical, laboratorial and radiographic predictors of Bordetella pertussis infection]

OBJECTIVE

To identify clinical, laboratorial and radiographic predictors for Bordetella pertussis infection.

METHODS

This was a retrospective study, which analyzed medical records of all patients submitted to a molecular diagnosis (qPCR) for B. pertussis from September 2011 to January 2013. Clinical and laboratorial data were reviewed, including information about age, sex, signs/symptoms, length of hospitalization, blood cell counts, imaging findings, coinfection with other respiratory pathogens and clinical outcome.

RESULTS

222 cases were revised. Of these, 72.5% had proven pertussis, and 60.9% were under 1 year old. In patients aging up to six months, independent predictors for B. pertussis infection were cyanosis (OR 8.0, CI 95% 1.8-36.3; p=0.007) and lymphocyte count >10(4)/μL (OR 10.0, CI 95% 1.8-54.5; p=0.008). No independent predictors of B. pertussis infection could be determined for patients older than six months. Co-infection was found in 21.4% of patients, of which 72.7% were up to six months of age. Adenovirus was the most common agent (40.9%). In these patients, we were not able to identify any clinical features to detect patients presenting with a respiratory co-infection, even though longer hospital stay was observed in patients with co-infections (12 vs. 6 days; p=0.009).

CONCLUSIONS

Cyanosis and lymphocytosis are independent predictors for pertussis in children up to 6 months old.

Prior exposure to Bordetella species as an exclusion criterion in the baboon model of pertussis

The baboon model of Bordetella pertussis infection is the newest and most clinically accurate model of the human disease to date. However, among the 15 experimentally infected baboons in this study, a subset of baboons did not exhibit the expected high bacterial colonization levels or increase in white blood cell count. Moreover, cultures of nasopharyngeal wash samples from several baboons suggested B. bronchiseptica coinfection. Analysis of serum antibodies recognizing filamentous hemagglutinin, pertussis toxin and B. pertussis lipo-oligosaccharide indicated that several baboons had likely been previously exposed to Bordetella species and that prior exposure correlated with partial protection from B. pertussis infection. Notably, all animals with a baseline Fha titer of 5 IU/ml or below exhibited symptoms typical of the model, suggesting this value can be used as inclusion criteria for animals prior to study enrollment. While B. pertussis infection is endemic to human populations and B. bronchiseptica is common in wild small mammals, this study illustrates that baboons can readily harbor both organisms. Awareness of Bordetella species that share antigens capable of generating protective immune responses and tracking of prior exposure to those species is required for successful use of the baboon model of pertussis.

Pertussis: Microbiology, Disease, Treatment, and Prevention

Pertussis is a severe respiratory infection caused by Bordetella pertussis, and in 2008, pertussis was associated with an estimated 16 million cases and 195,000 deaths globally. Sizeable outbreaks of pertussis have been reported over the past 5 years, and disease reemergence has been the focus of international attention to develop a deeper understanding of pathogen virulence and genetic evolution of B. pertussis strains. During the past 20 years, the scientific community has recognized pertussis among adults as well as infants and children. Increased recognition that older children and adolescents are at risk for disease and may transmit B. pertussis to younger siblings has underscored the need to better understand the role of innate, humoral, and cell-mediated immunity, including the role of waning immunity. Although recognition of adult pertussis has increased in tandem with a better understanding of B. pertussis pathogenesis, pertussis in neonates and adults can manifest with atypical clinical presentations. Such disease patterns make pertussis recognition difficult and lead to delays in treatment. Ongoing research using newer tools for molecular analysis holds promise for improved understanding of pertussis epidemiology, bacterial pathogenesis, bioinformatics, and immunology. Together, these advances provide a foundation for the development of new-generation diagnostics, therapeutics, and vaccines.

Rediscovering Pertussis

Pertussis, caused by Bordetella (B.) pertussis, a Gram-negative bacterium, is a highly contagious airway infection. Especially in infants, pertussis remains a major health concern. Acute infection with B. pertussis can cause severe illness characterized by severe respiratory failure, pulmonary hypertension, leucocytosis, and death. Over the past years, rising incidence rates of intensive care treatment in young infants were described. Due to several virulence factors (pertussis toxin, tracheal cytotoxin, adenylate cyclase toxin, filamentous hemagglutinin, and lipooligosaccharide) that promote bacterial adhesion and invasion, B. pertussis creates a unique niche for colonization within the human respiratory tract. The resulting long-term infection is mainly caused by the ability of B. pertussis to interfere with the host's innate and adaptive immune system. Although pertussis is a vaccine-preventable disease, it has persisted in vaccinated populations. Epidemiological data reported a worldwide increase in pertussis incidence among children during the past years. Either acellular pertussis (aP) vaccines or whole-cell vaccines are worldwide used. Recent studies did not detect any differences according to pertussis incidence when comparing the different vaccines used. Most of the currently used aP vaccines protect against acute infections for a period of 6-8 years. The resurgence of pertussis may be due to the lack of herd immunity caused by missing booster immunizations among adolescents and adults, low vaccine coverages in some geographic areas, and genetic changes of different B. pertussis strains. Due to the rising incidence of pertussis, probable solution strategies are discussed. Cocooning strategies (vaccination of close contact persons) and immunizations during pregnancy appear to be an approach to reduce neonatal contagiousness. During the past years, studies focused on the pathway of the immune modulation done by B. pertussis to provide a basis for the identification of new therapeutic targets to enhance the host's immune response and to probably modulate certain virulence factors.

Surveillance of pertussis: methods and implementation

INTRODUCTION

Pertussis or whooping cough is a respiratory disease caused by Bordetella pertussis or, to a lesser extent, by B. parapertussis. Vaccines against pertussis have been widely used for more than 50 years and have led to a significant reduction of morbidity and mortality. However, even in countries with a high vaccine coverage, the disease is still not well controlled. Surveillance is urgently needed.

AREAS COVERED

This review summarizes surveillance methods and gives examples that may be used when setting up a surveillance program or analyzing an outbreak. Expert commentary: Pertussis surveillance is urgently required in order to define the burden of disease, to adapt vaccine strategies according to the type of pertussis vaccine used and to follow the evolution of the bacteria.

Hospitalizations and deaths due to pertussis in children from 1996 to 2013

OBJECTIVES

To assess temporal trends of hospitalizations and deaths from pertussis in Brazilian children in the period of 1996-2013.

METHODS

This was a descriptive ecological study of temporal trends, based on the DATASUS database. The number of hospitalizations and deaths from pertussis in children up to 19 years of age from January 1996 to December 2013 was obtained. Descriptive statistics were applied for data analysis.

RESULTS

During the study period, a total of 19,047 hospital admissions from pertussis were recorded, of which 88.2% occurred in infants younger than 1 year. In the period 1996-2010, the mean annual number of admissions was 755, ranging from a maximum of 1179 in 2004 to a minimum of 400 in 2010. There was an increase of admissions in the last three consecutive years (2011, 2012, and 2013) with 1177, 2954 and 3589 hospitalizations, respectively. There were 498 deaths from pertussis throughout the study period, of which 96.8% occurred in children younger than one year. There was an increase in the number of deaths from pertussis in children in the years 2011, 2012, and 2013, with 40, 93, and 87 recorded deaths, respectively. The increase in hospitalizations and deaths from pertussis in children occurred in all regions of the country, with the highest increase observed in the Southeast, North and Northeast regions.

CONCLUSIONS

There was a substantial increase in hospitalizations and deaths from pertussis in children for three consecutive years (2011, 2012, and 2013) in all Brazilian regions. The most affected age group was that of children younger than one year.

Protecting Newborns Against Pertussis: Treatment and Prevention Strategies

Pertussis is a potentially severe respiratory disease, which affects all age groups from young infants to older adults and is responsible for an estimated 195,000 deaths occurred globally in 2008. Active research is ongoing to better understand the pathogenesis, immunology, and diagnosis of pertussis. For diagnosis, molecular assays (e.g., polymerase chain reaction) for detection of Bordetella pertussis have become more widely available and support improved outbreak detection. In children, pertussis vaccines have been incorporated into routine immunization schedules and deployed for pertussis outbreak control. Lower levels of vaccine coverage are now being observed in communities where vaccine hesitancy is rising. Additionally, recognition that newborn babies are at risk of pertussis in the USA and UK has led to recommendations to immunize pregnant women. Among adolescents and older adults in the USA, Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular pertussis (Tdap) Vaccines are recommended, but substantial individual- and system-level barriers exist that will make achieving national Healthy People 2020 targets for immunization challenging. Current antimicrobial regimens for pertussis are focused on reducing the severity of disease, reducing rates of sequelae, and minimizing transmission of infection to susceptible individuals. Continued surveillance for pertussis will be important to identify opportunities for reducing young infants' exposure and reducing the impact of outbreaks among school-aged children. Laboratory-based surveillance for newly emerging strains of B. pertussis will be important to identify strains that may evade protection elicited by currently available vaccines. Efforts to develop new-generation pertussis vaccines should be considered now in anticipation of vaccine development programs, which may require ten or more years to deliver a licensed vaccine.

Laboratory-based surveillance of pertussis using multitarget real-time PCR in Japan: evidence for Bordetella pertussis infection in preteens and teens

Between January 2013 and December 2014, we conducted laboratory-based surveillance of pertussis using multitarget real-time PCR, which discriminates among Bordetella pertussis, Bordetella parapertussis, Bordetella holmesii and Mycoplasma pneumoniae. Of 355 patients clinically diagnosed with pertussis in Japan, B. pertussis, B. parapertussis and M. pneumoniae were detected in 26% (n = 94), 1.1% (n = 4) and 0.6% (n = 2), respectively, whereas B. holmesii was not detected. It was confirmed that B. parapertussis and M. pneumoniae are also responsible for causing pertussis-like illness. The positive rates for B. pertussis ranged from 16% to 49%, depending on age. Infants aged ≤ 3 months had the highest rate (49%), and children aged 1 to 4 years had the lowest rate (16%, p < 0.01 vs. infants aged ≤ 3 months). Persons aged 10 to 14 and 15 to 19 years also showed high positive rates (29% each); the positive rates were not statistically significant compared with that of infants aged ≤ 3 months (p ≥ 0.06). Our observations indicate that similar to infants, preteens and teens are at high risk of B. pertussis infection.

Laboratory Diagnosis of Pertussis

The introduction of vaccination in the 1950s significantly reduced the morbidity and mortality of pertussis. However, since the 1990s, a resurgence of pertussis has been observed in vaccinated populations, and a number of causes have been proposed for this phenomenon, including improved diagnostics, increased awareness, waning immunity, and pathogen adaptation. The resurgence of pertussis highlights the importance of standardized, sensitive, and specific laboratory diagnoses, the lack of which is responsible for the large differences in pertussis notifications between countries. Accurate laboratory diagnosis is also important for distinguishing between the several etiologic agents of pertussis-like diseases, which involve both viruses and bacteria. If pertussis is diagnosed in a timely manner, antibiotic treatment of the patient can mitigate the symptoms and prevent transmission. During an outbreak, timely diagnosis of pertussis allows prophylactic treatment of infants too young to be (fully) vaccinated, for whom pertussis is a severe, sometimes fatal disease. Finally, reliable diagnosis of pertussis is required to reveal trends in the (age-specific) disease incidence, which may point to changes in vaccine efficacy, waning immunity, and the emergence of vaccine-adapted strains. Here we review current approaches to the diagnosis of pertussis and discuss their limitations and strengths. In particular, we emphasize that the optimal diagnostic procedure depends on the stage of the disease, the age of the patient, and the vaccination status of the patient.

Pertussis Accompanying Recent Mycoplasma Infection in a 10-Year-Old Girl

Recently, the incidence of pertussis has been increasing; however, reports on mixed infection of pertussis with other respiratory pathogens are rare in highly immunized populations. We report the case of a 10-year-old girl who presented with cough, post-tussive emesis, and fever. She was subsequently diagnosed with bronchopneumonia. Although she had received five doses of diphtheria-tetanus-acellular pertussis vaccine, polymerase chain reaction of her nasopharyngeal aspirate confirmed Bordetella pertussis infection. In addition, serologic testing for Mycoplasma pneumoniae was also positive. The patient was treated with roxithromycin without any complications. This is the first report of mixed B. pertussis and M. pneumoniae infection in Korea. To avoid under-diagnosis, pertussis should be considered in patients with chronic cough even when other respiratory pathogens have been documented.

Pertussis Prevalence in Korean Adolescents and Adults with Persistent Cough

We investigated the prevalence of pertussis in Korean adolescents and adults with persistent cough. Study population was adolescents (aged 11-20 yr) and adults (≥ 21 yr old) who showed persistent cough of 1-8 weeks' duration. Pertussis was diagnosed by culture, polymerase chain reaction (PCR), and serology. A total of 310 subjects participated in this study, and 76 cases (24.5%) met the criteria for laboratory-confirmed pertussis. The majority of the pertussis cases (66/76) were confirmed by serology, while 3 cases (1.0%) were diagnosed with culture, and 10 cases (3.2%) were detected with PCR. Of the 76 subjects diagnosed with pertussis, 20/86 cases were adolescents and 56/224 cases were adults. Neither adolescents nor adults received adolescent-adult booster against pertussis within the previous 5 yr. Pertussis can be a primary cause of persistent cough in Korean adolescents and adults.

Pertussis prevalence and its determinants among children with persistent cough in urban Uganda

BACKGROUND

We determined prevalence of pertussis infection and its associated host and environmental factors to generate information that would guide strategies for disease control.

METHODS

In a cross-sectional study, 449 children aged 3 months to 12 years with persistent cough lasting ≥14 days were enrolled and evaluated for pertussis using DNA polymerase chain reaction (PCR) and ELISA serology tests.

RESULTS

Pertussis prevalence was 67 (15% (95% Confidence Interval (CI): 12-18)) and 81 (20% (95% CI: 16-24)) by PCR and ELISA, respectively among 449 participating children. The prevalence was highest in children with >59 months of age despite high vaccination coverage of 94% in this age group. Study demographic and clinical characteristics were similar between pertussis and non-pertussis cases. Of the 449 children, 133 (30%) had a coughing household member and 316 (70%) did not. Among 133 children that had a coughing household member, sex of child, sharing bed with a coughing household member and having a coughing individual in the neighborhood were factors associated with pertussis. Children that had shared a bed with a coughing household individual had seven-fold likelihood of having pertussis compared to children that did not (odds ratio (OR) 7.16 (95% CI: 1.24-41.44)). Among the 316 children that did not have a coughing household member, age <23 months, having or contact with a coughing individual in neighborhood, a residence with one room, and having a caretaker with >40 years of age were the factors associated with pertussis. Age <23months was three times more likely to be associated with pertussis compared to age 24-59 months (OR 2.97 (95% CI: 1.07-8.28)).

CONCLUSION

Findings suggest high prevalence of pertussis among children with persistent cough at a health facility and it was marked in children >59 months of age, suggesting the possibility of waning immunity. The factors associated with pertussis varied by presence or absence of a coughing household member.

Pertussis serosurveillance study in Izmir, Turkey

Pertussis is a life-threatening, vaccine-preventable infection. Adults who can be asymptomatic may infect infants. The aim of this study is to determine the IgG antibody levels against pertussis toxin (PT) and filamentous hemagglutinin from 6 months to ≥60 years in Izmir, Turkey. A cluster sample design developed by Expanded Programme on Immunization of the World Health Organization was carried out for the selection of the study population, which consisted of 399 healthy subjects. In-house ELISA was studied in Turkish Public Health Institution. Antibody levels of <10 EU/ml, ≥10 EU/ml and ≥100 EU/ml were accepted as non-immune, immune and possible acute/recent infection, respectively. Anti-PT antibody levels were 8.5% <10 EU/ml, 68.2% 10-100 EU/ml and 23.3% ≥100 EU/ml; the latter was correlated with possible acute/recent infection. Results showed that pertussis is endemic, particularly among adolescents and adults, which is a threat for infants who have not completed their primary immunization.

Clinical and laboratory features of pertussis in hospitalized infants with confirmed versus probable pertussis cases

BACKGROUND

The clinical presentations of pertussis infection have considerable variation. Many infections and illnesses can cause prolonged repetitive paroxysmal cough that could be confused with Bordetella pertussis infection.

AIM

This retrospective study was designed to compare the clinico-laboratory findings between two groups of hospitalized infants with confirmed, and those who have clinical pertussis disease; to identify the possible additional diagnostic clues "for the diagnosis of confirmed pertussis disease".

SUBJECTS AND METHODS

The study population consisted of infants ≤12 months of age with clinical diagnosis of pertussis that fulfilled the World Health Organization definition for pertussis or those diagnosed by physicians. Clinico-laboratory findings were compared between two groups of patients (confirmed vs. clinical cases).

RESULTS

From a total of 118 infants admitted with a clinical diagnosis of pertussis, 16% (19/118) were confirmed by laboratory to have confirmed pertussis. Twelve of 19 (63%) and 71.99% of confirmed and clinical cases were younger than 6 months of age, respectively. For most patients, the duration of symptoms before hospitalization was <14 days. There were no significant differences between two groups of patients for paroxysmal cough and facial discoloration. However, whoop and apnea were more common among confirmed pertussis cases: P = 0.01, and P = 0.02, respectively. Leukocytosis (≥16,000/ml) (P = 0.01) and lymphocytosis (≥11,000) (P = 0.02) were reported significantly more frequently in confirmed pertussis cases.

CONCLUSION

Given the unavailability of a highly sensitive diagnostic test, in every afebrile patient with paroxysmal cough lasting for ≥7 days associated with whoop and/or apnea, particularly if accompanied by leukocytosis/lymphocytosis, pertussis disease should be considered. In this situation, prompt administration of empiric treatment for cases, and providing control measures to prevent infection transmission to contacts are recommended.

Clinical, laboratorial and radiographic predictors of Bordetella pertussis infection

OBJECTIVE: To identify clinical, laboratorial and radiographic predictors for Bordetella pertussis infection.METHODS: This was a retrospective study, which analyzed medical records of all patients submitted to a molecular dignosis (qPCR) for B. pertussis from September 2011 to January 2013. Clinical and laboratorial data were reviewed, including information about age, sex, signs/symptoms, length of hospitalization, blood cell counts, imaging findings, coinfection with other respiratory pathogens and clinical outcome.RESULTS: 222 cases were revised. Of these, 72.5% had proven pertussis, and 60.9% were under 1 year old. In patients aging up to six months, independent predictors for B. pertussisinfection were (OR 8.0, CI 95% 1.8-36.3; p=0.007) and lymphocyte count >104/µL (OR 10.0, CI 95% 1.8-54.5; p=0.008). No independent predictors of B. pertussisinfection could be determined for patients older than six months. Co-infection was found in 21.4% of patients, of which 72.7% were up to six months of age. Adenovirus was the most common agent (40.9%). In these patients, we were not able to identify any clinical features to detect patients presenting with a respiratory co-infection, even though longer hospital stay was observed in patients with co-infections (12 vs. 6 days; p=0.009).CONCLUSIONS: Cyanosis and lymphocytosis are independent predictors for pertussis in children up to 6 months old.

Pertussis resurgence in a highly vaccinated population, Mazandaran, North of Iran 2008-2011: an epidemiological analysis

OBJECTIVE

To describe the epidemiological characteristics of pertussis cases reported to Mazandaran Center for Diseases Control and Prevention (P-CDC) during the years 2008-2011 in Mazandaran, North of Iran.

METHODS

The patients included were those who fulfilled the WHO definition for pertussis or those clinically diagnosed by physicians. The demographic features of cases, their vaccination status, the incidence rate per 100,000 population, the relative proportion of cases for each age group, and their relation to vaccination status of the patients were all determined.

RESULTS

During the study period, a total of 518 cases of pertussis were reported; of which 43 were confirmed. The highest incidence rate and the largest proportion were 135.5 cases/100,000 and 37.7 %, respectively, observed in infants <12 mo of age. Almost 35.7 % of the cases were under vaccinated, however 54.4 % of them were fully vaccinated.

CONCLUSIONS

Pertussis infection has re-emerged in Mazandaran. It has caused a significant health problem in the susceptible young infants, and also among completely vaccinated children. Implementing strategies to protect these vulnerable infants and studies to evaluate the immunogenicity and efficacy of pertussis vaccine in Iran is recommended. It was difficult to confirm pertussis in the majority of cases, therefore, providing and improving laboratory diagnostic methods seems to be an urgent requirement.

Pertussis may be the cause of prolonged cough in adolescents and adults in the interepidemic period

Objective

This study was aimed to evaluate the prevalence of pertussis in adolescents and adults with cough lasting more than 14 days and less than 30 days.

Methods

This is a prospective observational study in interepidemic period of pertusis. Ten public health outpatient clinics in the city of Recife, Brazil, were randomly selected for the study. The study population consisted of individuals aged 10 years and over with cough that had lasted between 14 and 30 days. Nasopharyngeal swabs were collected for culture and PCR in order to identify Bordetella pertussis. We adopted the Centers for Disease Control and Prevention in the US (CDC) definition of cases of pertussis.

Results

A total of 192 individuals were identified as suspected cases. Their mean age was 40.7 years. Pertussis was confirmed in 10 of the 192 suspected cases, with an estimated prevalence of 5.21% (95% confidence interval 2.03–8.38). All cases met the clinical case definition for pertussis; one suspect had both culture and PCR positive. PCR confirmed 100% of the cases, 7/10 by PCR and 3/10 by epidemiological linkage with a case confirmed by PCR.

Conclusion

During an interepidemic period, 1 in 20 cases of prolonged cough had pertussis, suggesting this is an important cause of prolonged cough in adolescents and adults.

Diagnosis and laryngeal complications of Bordatella pertussis infection in the ambulatory adult population

Bordatella pertussis infection leads to a chronic, debilitating, and paroxysmal cough that can last for months to years. Incidence of B pertussis in the immunized adult population is rising nationwide, but many otolaryngologists are unfamiliar with the diagnosis and management of this disease. Adults often present late in the disease process when traditional diagnostic testing is ineffective and without the classic pediatric symptoms of whooping cough. As a result, B pertussis infections in adults are often overlooked or misdiagnosed as asthma exacerbations or viral bronchitis, leading to increased morbidity, unnecessary testing, and additional exposure of vulnerable populations to the pathogen. This commentary describes 3 adult cases of B pertussis confirmed with serum testing in the ambulatory population and describes varied presentations based on time from initial infection. Specific emphasis is presented on the physical manifestations of the disease in laryngeal structures, methods of diagnosis, and recommendations for treatment.

Prevalence of Bordetella infection in a hospital setting in niamey, niger

Bordetella pertussis still poses an important health threat in developing countries. In Niger, notified pertussis cases are few despite the low diphtheria-tetanus-pertussis/pentavalent vaccine coverage. We aimed to estimate the prevalence of B. pertussis in children aged <5 years consulting at a pediatric ward. A 5-month study in 2011 recruited 342 children with respiratory symptoms at the National Hospital of Niamey. Nasopharyngeal aspirates were tested by culture and real-time polymerase chain reaction. Overall, 34 (11.2%) of the 305 available nasopharyngeal aspirates tested by real-time polymerase chain reaction were positive for a Bordetella spp., with an estimated prevalence of 8.2 cases per 1000 children aged <5. None was notified to the surveillance network. A single specimen was positive on culture. This study, the first to provide laboratory-confirmed data on pertussis in Niger, highlights the need to sensitize health care personnel to actively notify clinical cases and to integrate laboratory diagnosis in the existing surveillance system.