Pertussis

The incubation period varies from 7 to 14 days. It is a disease of childhood with 90% of cases occurring below 5 years of age. 

The disease manifests in 3 stages: first is the catarrhal stage, followed by the paroxysmal stage and lastly, the convalescent stage. During the catarrhal stage, patients are highly infectious and their cultures from respiratory secretions are positive in most of the cases.

Malaise, anorexia, coryza, mild cough, mucoid rhinorrhoea and conjunctivitis are present. Paroxysms of cough begin about a week later. Paraoxysms with the classic inspiratory whoop are seen mainly in younger children in whom the lumen of the respiratory tract is compromised by mucosal secretion and mucosal oedema. The whoop results from air being forcefully drawn through the narrowed tract.

The disease runs an atypical course in partially immunised older children and in adults in whom cough is persistent and prolonged often without a whoop which makes diagnosis difficult for them.

Paraoxysms usually end in vomiting. Paraoxysmal stage lasts for about 2-6 weeks. Diminishing intensity and frequency of cough indicate the onset of the convalescent stage which may continue for 1-2 weeks.

Infants and young children are more sensitive to complications. Respiratory complications include otitis media, pneumonia either due to Bordetella pertussis or bacterial pneumonia.

At the peak of the disease, seizures and encephalopathy may occur. Malnutrition is often the end result in infancy and early childhood.

The diagnosis is suggested after a clinical examination, a characteristic whoop and a history of contact with infected individual will be noted. On examination, a typical whoop will be heard. Patient may be febrile. Signs of coryza will be observed. Conjunctival suffusion and petechia and ulceration of the frenulum of the tongue are usual.

Blood reports will show lymphocytosis due to elaboration of lymphocyte promoting factor which is a characteristic of B. petussis. Lymphocytes may account for 90% of total WBC. Low erythrocyte sedimentation rate (ESR) may be noted.

Specific diagnosis depends upon recovery of pertussis from nasopharyngeal swab or cough plate cultures. Cultures are usually positive in early stage of the disease. Direct fluorescent antibody and counter immune electrophoresis are methods of rapid diagnosis, though these are rarely used in clinical practice.

Immediate treatment should be started to prevent any respiratory or neurological complications which are serious in infants. Any complication or dehydration is an immediate indication for hospitalisation. Good nutrition and adequate hydration are important.

Antibiotics, mainly erythromycin, should be started early immediately in catarrhal stage as it will abort or reduce the intensity of the infection. It also terminates respiratory tract carriage of pertussis thus reducing the communicability. In the paroxysmal stage, antibiotics have little role to play in altering the course of the disease. Complications should be managed symptomatically [8].

The main objective of treatment is to reduce the spread of infection, ameliorate symptoms and prevent further compications. Thus, with proper diagnosis and prompt treatment the outlook of pertussis is very good with complete recovery. The chronic cough will resolve within 3 months.

Recurrence of cough and symptoms may occur after 6 months. In adolescents, adults and a little older children prognosis [6] is very good. Infants less than a year have a higher risk of complications, mainly bacterial pneumonia. Mortality of pertussis is mainly due to infants who have not received vaccination [7].

The causative agent of this infection is Bordetella pertussis which is a Gram-negative coccobacillus. These bacteria are spread by droplet infection, as a result of an infected person’s sneeze or cough, these droplets are released in the air. This is a highly infectious disease which spreads to infants or children through the family members who may not even be aware of the infection. On inhalation of this infection, the bacteria attach to the nasopharyngeal epithelium, proliferate and spread through the ciliated epithelium.

There are a number of risk factors which facilitate its transmission, mainly individuals who are not immunised, infants and children who are in close contact with infected people and parents who refuse to give vaccination to their children due to misconceptions [2].

Health care providers who are in close contact with infected individuals are also at a risk. In case of an epidemic outbreak, all individuals staying in crowded areas, schools or hospitals are at high risk of contracting this infection.

Pertussis occurs worldwide and continues to be a global problem in spite of vaccination being widely available. The post vaccination era has seen a 20 fold decline in the incidence. Periodic epidemics [3] however continue to occur worldwide.

Recent studies from WHO suggested that 260,000 children under the age of 5 years die from pertussis every year. Thus in spite of primary vaccination, pertussis continues to be a health hazard. Prior to vaccination, pertussis was a common cause of illness and death.

Pertussis occurs all throughout the year but is noticed more in summer. Pertussis affects all ages, males and females are equally affected. Children and infants are affected more, especially in the age range from 6 months to a year. A study in Australia reported that adults with obesity or asthma were more likely to have pertussis [4].

With improved vaccines, cases have been reported more in adults and adolescents. Infants maybe infected before vaccination. Alternatively, post vaccination immunity may wane in older children, who may suffer from a mild or modified form of the disease which is difficult to recognize.

The organism is spread by droplets from infected, untreated patients. Pertussis main pathogenesis is due to the toxin that it elaborates. Clinical features depend upon the host response to various antigens, the capsule, cell wall and cytoplasm of the organism.

The bacterium gets adhered to the respiratory epithelium and destroys the ciliated epithelium which results in the first catarrhal stage. A lymphocytosis promoting factor probably plays an important role. Endotoxin does not seem to contribute to the pathogenesis. Bacteria also seem to invade the tissue and are seen in alveolar macrophages.

Pathological changes induce inflammation of the mucosal lining of the respiratory tract. Debris gets accumulated in the respiratory tract. Bronchopneumonia develops, with necrosis and desquamation of the superficial epithelium of the bronchi.
Bronchiolar obstruction and atelectasis can result from accumulation of secretions. Bronchiectasis may develop and persist. Due to accumulation of mucus secretions, coughing occurs.

Changes in brain and liver are seen in severe disease especially in infants and the cause is anoxia. The bacteria are not detected in blood culture [5].

Strict respiratory isolation is desirable for 6-7 days after starting antibiotic therapy, thus reducing contact with other indiviuals. Chemoprophylaxis with erythromycin is ideal for immunised contacts under 2 years of age.

Routine primary immunisation at 6, 10, 14 weeks along with booster doses at 18 months and 5 years are a must [9].
Side effects of vaccination include fever, injection site pain, erythema and irritability.

All health care professionals should also take the vaccine.
Pertussis is an easily preventable disease as effective active immunisation is available [10].

Pertussis is an acute infectious disease caused by Bordetella pertussis. B. pertussis [1] is a Gram-negative coccobacillus. This is a serious infection common in infancy and childhood with serious complications. Pertussis occurs worldwide and epidemic outbreaks are common. Humans are both natural hosts and reservoirs of this infection.

Pertussis is highly communicable and spreads by droplet infection. It is also known as whooping cough or ‘cough of 100 days’. The symptoms at the start are mild and can be confused with other upper respiratory infections. It presents in 3 stages where it starts with an inflammatory coryza and later progresses onto severe episodes of coughing spasms.

Prevention is in the form of vaccination which is of great importance especially in children due to severity of secondary bacterial infections. The mainstay of treatment is antibiotics to reduce the severity of the disease.

It is known as whooping cough for the distinct ’whoop’ sound produced while coughing which is of a very high pitch and usually occurs when inhalation is attempted.

Pertussis or whooping cough is an acute infectious disease caused by a bacterium called as Bordetella pertussis. This is a highly contagious disease spread by close contact, sneezing, and coughing. This infection results in severe violent episodes of coughing with a characteristic whoop sound when the patient attempts to breathe.

The bacteria can cause a serious upper respiratory tract infection especially in infants which can result in severe complications and can even be fatal. When an infected person sneezes or coughs, small mucus droplets containing the Bordetella pertussis bacteria get released and the infection easily spreads to other people.

This infection persists for at least 6-8 weeks. It starts with symptoms similar to common cold and later on progresses to severe episodes of spasmodic coughing which are uncontrollable. Coughing can end in vomiting.

Immediate medical care should be provided as it helps to reduce the transmission of this infection as well as reduces severity and the complications which can occur. Antibiotics are started and infected individuals are kept separate especially away from infants and non-vaccinated individuals.

Blood tests are done but diagnosis is usually made after a good clinical examination. Infants need strict supervision as they have the highest risk of developing respiratory complications.

Prevention is the best approach for this disease. Vaccination is the most effective way of prevention against pertussis. All children should be vaccinated according to the immunisation schedule regularly. Booster doses should also be given. Adults above 65 years can take the adult vaccine especially in case of a pertussis epidemic.

With prompt antibiotics there is complete recovery. Pertussis has a good outlook provided immunisation is followed.

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