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Pertussis


Pertussis, also known as whooping cough, is an acute and extremely contagious disease that affects between 5,000 to 7,000 people in the United States each year. It is caused by a gram-negative bacterium known as Bordatella pertussis, the culprit of 30 to 50 million Pertussis cases worldwide that result in over 300,000 deaths annually.

Despite there being available DTP (Diptheria-Tetanus-Pertussis) and DtaP ( Diptheria-Tetanus-accelular-Pertussis) vaccines for the disease, pertussis still remains one of the leading causes of infant deaths worldwide, with a 90% mortality rate in developing countries. This is due to the failure to vaccinate infants to protect them against the disease.

PERTUSSIS SIGNS AND SYMPTOMS

While infants with a lack of or incomplete immunization belong to the highest risk group, adolescents and adults whose past vaccinations have worn off are also susceptible. Having had a previous vaccination or infection is still not a guarantee of long-term immunity from the disease. As a result, even older children and adults can get Pertussis, although the symptoms may be milder if there have been previous vaccinations.

Whooping cough is a respiratory infection that is characterized by a harsh hacking cough. This is followed by an intake of breath making the sound of a 'whoop', hence its name. In infants and children the whoop is characteristically higher in pitch compared to adults.

PERTUSSIS CAUSES

Pertussis can be passed on by direct contact with an infected person's respiratory discharges, such as mucus or saliva, particularly when a person inadvertently inhales infected droplets conveyed by a cough or sneeze.

As soon as the bacteria enters the system, it multiplies and creates toxins which compromises the respiratory tract's immunity. There is a two-day incubation period in which the infected persons exhibit symptoms of a mild respiratory infection like coughing, sneezing or a runny nose. This is known as the the catarrhal stage, the first stage of Pertussis.

After a week or two, the second stage of the infection begins and the tone of the cough changes. The thick mucus that an infected person accumulates in the airways will cause frequent coughing fits followed by a “whooping” sound whenever they gasp for breath. This is caused by an inflammation that results in a narrowing of the trachea, or windpipe.

The coughing fits usually peak during the nighttime, and can be brought about by simple stretching, laughing, yawning or yelling. Infants or children who have the whooping cough will often turn blue in the face due to lack of oxygen, and experience episodes of choking because of the struggle to breathe after going through the coughing spells. These coughing spells almost always cause exhaustion in infants and children. Sometimes the paroxysms of coughing can be so intense, they are immediately followed by vomiting. Frequent vomiting from whooping cough symptoms can eventually lead to malnutrition and dehydration.

Other symptoms of Pertussis include nasal congestion and a runny nose, sneezing, a slight fever, dry cough, thick phlegm, and loss of appetite. There are numerous instances when the severity of the cough is such that small blood vessels in the upper body's skin surface rupture, resulting in tiny red spots. Small broken blood vessels may also appear in the whites of the eyes.

PERTUSSIS COMPLICATIONS

Complications of Pertussis include ear infections, seizures, pneumonia, slowed or stopped breathing, and even brain damage due to lack of oxygen (encephalitis) in infants. In children, the coughing fits may result in injury to the chest wall muscles and the development of a hernia (the protrusion of an intestinal loop through weak abdominal muscles). Adults may also acquire hernias, as well as bruised or broken ribs.

After one to two months, and sometimes after as long as 10 weeks, the disease enters its third stage where the coughing fits slowly diminish. This is known as the convalescent stage where the cough eventually disappears after two to three weeks, but is liable to reoccur from time to time for several months during this gradual recovery.

pertussis
Image: Pertussis

PERTUSSIS DIAGNOSIS

It may be difficult to diagnose Pertussis in its early stages because its symptoms resemble the more common respiratory ailments like a cold or the flu, and sometimes even bronchitis. Doctors may need to order several medical tests to make an accurate diagnosis of whooping cough.

One of these tests include a nose or throat culture, where the doctor takes swabs of the secretions from the mucus membranes of the nose or throat. This culture will be subjected to laboratory testing for the presence of the Bordatella pertussis bacterium.

The doctor may also order a blood sample to check the patient's white blood cell count. White blood cells are responsible for fighting infections within the body, and a higher white blood cell count may signal the presence of an infection. Another test is a chest X-ray to check for fluid in the lungs whenever there is a secondary complication of pneumonia, as well as other related respiratory infections.

PERTUSSIS TREATMENT

As Pertussis is a contagious disease, the doctor may recommend avoiding contact with other people to prevent passing the infection. Generally, treatment will depend upon the age of the patient, the stage of the disease and the symptoms exhibited. Administering antibiotic medications like erythromicin, clarithromycin or azithormycin will shorten the duration of the disease and period of communicability, and if administered during the catarrhal stage, symptoms are likely to be less severe.

Infants younger than 3 months and older babies will usually require hospital care to lessen the risks of dangerous complications which can occur as long as the infection exists. Infants who are hospitalized are usually isolated to prevent the spread of the bacteria. They will receiv intravenous antibiotics for the infection and cortiscosteriod medication to reduce the inflammation of the airways. More often than not, very young infants may need to have their breathing constantly monitored, and a suction may be applied to remove the thick mucus. Sometimes oxygen may even be needed.

Older children, adolescents, and adults are likely to be given a prescription of erythromycin or azithromycin and advised to take bed rest, drink plenty of fluids, use a vaporizer to soothe irritated lungs, and don a mask to prevent spreading the infection. However, there is still no effective treatment to eradicate the severe coughing spells that come with Pertussis.

The most effective way to prevent Pertussis is to have infants immunized with the Pertussis vaccine. This vaccine is usually given together with the Diptheria and Tetanus vaccines in DTP or DtaP. Three shots of this vaccine are needed for full immunity against whooping cough, although pediatricians recommend an additional five shots as soon as the child reaches his 6th year.


As this childhood vaccine immunity wears off by the time a child turns 11, there is also a booster vaccine available for adolescents and teenagers called the Tdap (Diptheria and Pertussis vaccine). According to the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention, it is also recommended that adults, particularly those who have babies and children, should receive a Tdap booster shot every 10 years to protect them from the disease as well as to lower the risk of transmitting it.

Whooping cough is a potentially fatal disease that causes a high mortality rate in infants who have had no or incomplete vaccination against the bacteria. In adults and older children, it is not an ailment which will last for only a week or so. The duration of a Pertussis bacterial infection can run for up to 6 weeks or longer.

While the current Pertussis vaccines have proven to be very effective, scientists are experimenting with new molecular typing methods to identify the different strains of the bacteria, apply and evaluate newly-developed diagnostic tests, and study the effectiveness of acelluar pertussis vaccines in order to control any possible outbreaks.



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