pertussis

pertussis
Name	Pertussis
Synonyms	Whooping cough
Field	Infectious disease
Symptoms	Paroxysmal coughing, inspiratory whoop, posttussive vomiting
Complications	Pneumonia, seizures, encephalopathy, apnea in infants
Onset	Gradual after incubation period
Duration	Weeks to months (can be prolonged)
Causes	Bordetella pertussis
Diagnosis	Clinical assessment, culture, PCR, serology
Prevention	Vaccination with DTaP, Tdap; cocooning strategies
Treatment	Macrolide antibiotics; supportive care, hospitalisation for severe cases

pertussis is an acute respiratory infection caused by the bacterium Bordetella pertussis. It classically produces prolonged paroxysmal coughing and an inspiratory "whoop" and is vaccine-preventable, yet remains a cause of morbidity and mortality worldwide, particularly among infants and unimmunized populations. Public health responses involve immunization programs, surveillance by agencies such as the World Health Organization, and outbreak control measures used in settings ranging from schools to long-term care facilities.

Introduction

Pertussis is characterized by a biphasic clinical course following an incubation period after exposure in settings such as households, daycare centers, military barracks, and correctional facilities. Historically recognized in clinical descriptions by physicians in the 16th to 19th centuries, the bacterium Bordetella pertussis was isolated in the early 20th century, prompting vaccine development that involved investigators and institutions like Louis Pasteur-era laboratories and later national public health institutes. Modern control relies on immunization policies implemented by ministries such as the United States Department of Health and Human Services and agencies like the Centers for Disease Control and Prevention.

Signs and symptoms

The illness often progresses through catarrhal, paroxysmal, and convalescent phases described in clinical manuals used at hospitals such as Mayo Clinic, Johns Hopkins Hospital, and Great Ormond Street Hospital. Early catarrhal symptoms resemble common upper respiratory infections seen in clinics associated with Harvard Medical School and University College London, including rhinorrhea, low-grade fever, and mild cough, which can be mistaken for infections caused by pathogens monitored by the European Centre for Disease Prevention and Control. The paroxysmal phase features repeated violent coughing fits, the classic inspiratory whoop, and posttussive vomiting noted in pediatric wards at institutions like Boston Children's Hospital and SickKids Hospital, with high risk of apnea and cyanosis among neonates treated in neonatal intensive care units at centers such as Necker–Enfants Malades Hospital. Convalescence may be protracted, with cough lasting weeks to months documented in longitudinal cohorts run by universities including Stanford University and University of Melbourne.

Cause and pathophysiology

Pertussis is caused by the gram-negative coccobacillus Bordetella pertussis, which adheres to ciliated epithelial cells of the respiratory tract using adhesins studied in laboratories at institutions such as Pasteur Institute, Imperial College London, and Max Planck Society research groups. Key virulence factors include pertussis toxin, filamentous hemagglutinin, and tracheal cytotoxin, biochemical mechanisms investigated by teams affiliated with Johns Hopkins University, University of Oxford, and Karolinska Institutet. These toxins disrupt mucociliary clearance and modulate immune responses, producing lymphocytosis and local tissue damage observed in pathology departments at Mayo Clinic and comparative studies by the National Institutes of Health. Transmission occurs via respiratory droplets in community settings tracked by municipal health departments in cities such as New York City, London, and Melbourne.

Diagnosis

Diagnosis combines clinical criteria used in guidelines from organizations like the World Health Organization, Centers for Disease Control and Prevention, and national public health agencies, with microbiological tests performed in reference laboratories such as those at Public Health England and Statens Serum Institut. Polymerase chain reaction assays and bacterial culture from nasopharyngeal specimens are standard in clinical microbiology units at hospitals including Cleveland Clinic and Karolinska University Hospital, while serology may be used in later stages in research programs at universities like University of Toronto and University of Copenhagen. Differential diagnosis includes respiratory infections caused by agents investigated by centers such as Pasteur Institute and Institut Pasteur de Dakar, and clinicians in emergency departments at institutions like Mount Sinai Hospital must distinguish pertussis from conditions seen in pediatric clinics at Royal Children's Hospital.

Prevention and vaccination

Prevention centers on immunization with whole-cell and acellular vaccines developed through collaborations among manufacturers, research institutes, and public health agencies such as GlaxoSmithKline, Sanofi, Centers for Disease Control and Prevention, and national immunization programs run by ministries like the Australian Department of Health. Childhood schedules using DTaP, and adolescent/adult boosters with Tdap, are recommended by advisory committees such as the Advisory Committee on Immunization Practices and implemented in national programs in countries including United States, United Kingdom, Australia, and Japan. Strategies such as maternal vaccination during pregnancy, postpartum cocooning promoted by hospitals like Karolinska University Hospital, and school-entry requirements enforced by local authorities in jurisdictions such as California aim to protect infants. Vaccine effectiveness, waning immunity, and antigenic changes in circulating strains have been topics of study at institutions including Oxford Vaccine Group, University of Cambridge, and CDC surveillance networks.

Treatment and management

Treatment includes macrolide antibiotics—such as azithromycin, clarithromycin, and erythromycin—recommended in clinical practice guidelines from bodies like World Health Organization and Infectious Diseases Society of America and used in hospital formularies at centers such as Massachusetts General Hospital and Singapore General Hospital. Early antibiotic therapy reduces transmission and may attenuate symptoms if given in the catarrhal phase; supportive care for complications involves respiratory support available in intensive care units at hospitals like Great Ormond Street Hospital and Robert Wood Johnson University Hospital. Prophylactic antibiotics for close contacts and outbreak control measures are coordinated by public health agencies such as Public Health England and state health departments in the United States.

Epidemiology and history

Pertussis incidence has fluctuated with vaccine introduction, policy changes, and pathogen evolution, documented in epidemiological reports from the World Health Organization, European Centre for Disease Prevention and Control, and national agencies such as the Centers for Disease Control and Prevention. Major outbreaks occurred historically in urban centers such as London, Paris, and New York City, and contemporary resurgences have been reported in regions including California, Australia, and parts of Europe despite high vaccine coverage, prompting research at universities like University of Oxford, Johns Hopkins University, and Monash University. Mortality historically affected infants and the elderly, with reductions following mass immunization campaigns coordinated by organizations such as UNICEF and national ministries of health. Ongoing surveillance, vaccine research, and public health interventions involve collaborations among academic institutions, manufacturers, and agencies including WHO, CDC, and European Medicines Agency.

Category:Infectious diseases