Pertussis (Whooping Cough)

Introduction

Pertussis, commonly known as Whooping Cough, is a highly contagious bacterial infection of the respiratory tract. It mainly affects infants and young children, but adults can also get infected. The disease is named for the characteristic “whooping” sound made when the patient gasps for air after a severe coughing fit.

What Is Pertussis (Whooping Cough)?

Pertussis is a respiratory infection caused by the bacterium Bordetella pertussis. It attacks the lining of the respiratory tract, leading to inflammation and severe coughing spells. The disease spreads through airborne droplets when an infected person coughs or sneezes.

The infection progresses slowly — starting with mild cold-like symptoms before advancing to severe coughing fits that can last for weeks or even months. That’s why pertussis is sometimes called the “100-day cough.

Causative Agent: Bordetella Pertussis

• Scientific name: Bordetella pertussis
• Type: Small, Gram-negative coccobacillus
• Transmission: Airborne droplets
• Survival: It does not survive long outside the human body
• This bacterium produces toxins that damage the respiratory lining and interfere with the immune system, leading to prolonged coughing.

Mode of Transmission

1. Coughing or Sneezing: Infected droplets enter the air and can be inhaled by others.
2. Close Contact: Direct contact with respiratory secretions (like saliva).
3. Crowded Places: Schools, hospitals, and daycare centers are common transmission sites.

One infected person can spread the bacteria to up to 12–15 other people, making it one of the most contagious diseases in children.

Incubation Period

The incubation period for pertussis ranges from 7 to 10 days (can be up to 21 days). During this time, the bacteria multiply in the respiratory tract before symptoms appear.

Stages of Pertussis

Pertussis infection occurs in three clinical stages:

1. Catarrhal Stage (1–2 weeks)

• Runny nose
• Mild cough
• Low-grade fever
• Sneezing
• Fatigue
• This is the most contagious stage.

2. Paroxysmal Stage (2–6 weeks or more)

• Severe and repetitive coughing fits (paroxysms)
• Characteristic “whooping” sound when inhaling after cough
• Vomiting after coughing
• Cyanosis (bluish lips or face due to lack of oxygen)
• Exhaustion after coughing fits
• Infants may experience apnea (brief pauses in breathing)

3. Convalescent Stage (2–3 weeks or longer)

• Gradual recovery
• Cough decreases in frequency and severity
• However, mild coughing may persist for several weeks

Symptoms of Pertussis

• Infants (<6 months) Apnea (breathing pauses), poor feeding, minimal cough, cyanosis
• Children (1–10 years) Intense coughing fits, “whoop” sound, vomiting, exhaustion
• Teens & Adults Persistent dry cough, mild “whooping,” sore ribs from coughing

Other symptoms can include:

• Nasal congestion
• Watery eyes
• Sore throat
• Trouble breathing after cough spells

Complications of Pertussis

In Infants and Children:

• Pneumonia (most common complication)
• Seizures
• Apnea (temporary breathing pauses)
• Encephalopathy (brain inflammation due to lack of oxygen)
• Dehydration and weight loss from vomiting

In Adults:

• Rib fractures from intense coughing
• Hernias
• Urinary incontinence

Diagnosis of Pertussis

Diagnosis involves clinical evaluation and laboratory tests.

1. Clinical Examination

• Doctors check for characteristic “whooping” cough and prolonged cough spells.
• Medical history and vaccination status are also reviewed.

2. Laboratory Tests

• Nasopharyngeal swab or aspirate: Collected from the back of the nose and throat.
• Culture test: Gold standard for pertussis diagnosis (results in 7–10 days).
• Polymerase Chain Reaction (PCR): Detects bacterial DNA quickly.
• Serology (Blood test): Checks for antibodies (useful in late stages).

Treatment of Pertussis

Early treatment can reduce the severity and spread of infection.

1. Antibiotic Therapy

Macrolide antibiotics are most effective:

• Azithromycin
• Clarithromycin
• Erythromycin
• In infants below 1 month, azithromycin is preferred due to safety.

2. Supportive Care

• Keep the patient in a calm, quiet environment.
• Provide adequate fluids to prevent dehydration.
• Use a cool mist humidifier to ease breathing.
• Frequent, small meals help avoid vomiting.

3. Hospitalization

• Required for infants under 6 months or patients with breathing difficulties.
• Oxygen therapy may be needed in severe cases.
• Isolation to prevent spreading the infection.

Vaccination Against Pertussis

• Vaccination is the most effective way to prevent whooping cough.
• DTaP Vaccine (for children)
• Protects against Diphtheria, Tetanus, and Pertussis
• Given at ages:

1. 2 months
2. 4 months
3. 6 months
4. 15–18 months
5. 4–6 years

• Tdap Vaccine (for adolescents & adults)
• Booster dose recommended at 11–12 years and once every 10 years thereafter.
• Pregnant women should receive Tdap during each pregnancy (between 27–36 weeks) to protect newborns.

Prevention of Pertussis

1. Maintain Good Hygiene:

• Cover mouth and nose while coughing or sneezing.
• Use tissues or elbows instead of hands.
• Dispose of used tissues properly.

2. Avoid Close Contact:

• Keep infected individuals away from infants and unvaccinated people.

3. Isolation of Infected Patients:

• Avoid attending school or work until at least 5 days after starting antibiotics.

4. Early Diagnosis and Treatment:

• Timely medical care helps control community outbreaks.

5. Public Awareness:

• Educating parents about vaccination schedules and symptoms ensures early protection.

Epidemiology of Pertussis

• Despite global vaccination programs, pertussis still causes millions of cases each year worldwide.
• WHO estimates: Around 24 million cases and 160,000 deaths annually, mostly among infants.
• Outbreaks occur every 3–5 years even in developed countries.
• Unvaccinated and partially vaccinated children are most vulnerable.

Pertussis in India

In India, pertussis remains a public health concern due to:

• Incomplete immunization coverage
• Limited awareness among parents
• Misdiagnosis as common cough or cold
• The Universal Immunization Program (UIP) includes DPT vaccine (Diphtheria, Pertussis, Tetanus) as part of routine childhood immunization, helping to reduce cases significantly.

Home Remedies and Care Tips

1. Humidified Air: Use a vaporizer to soothe airways.
2. Hydration: Give plenty of fluids like water, soups, and juices.
3. Rest: Encourage adequate rest and sleep.
4. Avoid Irritants: Keep away from smoke, perfumes, or dust.
5. Small Meals: To prevent vomiting after cough spells.

Prognosis (Recovery and Outlook)

• With proper treatment and vaccination, most patients recover fully.
  However:
• Infants under 6 months are at higher risk of complications.
• Cough may persist for up to 3 months after recovery.
• Immunity fades over time, so booster doses are essential.

---

Public Health Importance

Pertussis control requires:

• Early diagnosis
• Timely vaccination
• Community awareness
• Health authorities must conduct mass immunization programs, monitor outbreaks, and ensure vaccines are available even in rural areas.

---

Key Facts about Pertussis

• Caused by Bordetella pertussis bacterium.
• Highly contagious respiratory infection.
• Preventable through DTaP/Tdap vaccination.
• Early antibiotic treatment helps reduce severity.
• Infants are most at risk of severe complications.
• Immunity from vaccination or infection fades with time.