Infectious disease specialist warns about pertussis-causing bacteria

Pertussis is a special infectious disease that develops gradually and passes through three periods, said Andrei Pozdnyakov, candidate of medical sciences, infectious diseases doctor at Invitro. He told Izvestia on February 18 about how to distinguish the onset of pertussis from the usual cold or ARVI, what bacteria cause the disease and how effective modern vaccination is.

"Whooping cough is characterized by cyclicity: periods of rising incidence are replaced by periods of decline. Currently, we are in an upswing phase. The COVID-19 pandemic had a significant impact: during the self-isolation, many people, including children, missed routine vaccination. It is important to note that vaccination against pertussis is included in the calendar of childhood vaccinations, "- explained the doctor.

The causative agent of pertussis - the bacterium Bordetella pertussis (Bordetella pertussis) remains practically unchanged for a long time. No significant mutations have occurred in its structure, which could affect the clinical manifestations of the disease, the general picture of the disease and the resistance of the microorganism to treatment.

"What is particularly interesting about the causative agent of pertussis is its paradoxical nature. The bacterium itself is incredibly sensitive to external factors, we can say that it is "tender as a rose" and extremely poorly adapted to survival in the external environment. However, despite this, the microorganism has developed very effective mechanisms of human-to-human transmission," the specialist added.

The insidiousness of pertussis is that the onset of the disease is very deceptive. Unlike acute infections like influenza, measles or whooping cough, pertussis starts imperceptibly, with mild respiratory symptoms. The first period, called the period of a simple cough, is characterized by the usual signs of a cold - lasting about a week to a week and a half.

After 1.5 to 2 weeks comes the second period, when the cough becomes spasmodic, with characteristic reprisals (audible breaths between coughing fits).

"The fact is that Bordetella produces a strong toxin that affects the cough center in the brain. This mechanism is part of the microbe's evolutionary strategy: a strong spasmodic cough helps the bacteria spread the maximum distance, increasing the chances of infecting others. The period of spasmodic cough can last up to 1-1.5 months, and even if at this time to apply antibiotics and destroy the pathogen, the cough will still continue for the prescribed period because of the already produced toxin, "- said Pozdnyakov.

The period of spasmodic cough is the most agonizing for patients with whooping cough. It is especially severe in moderate and severe forms of the disease. Coughing attacks can provoke various factors: temperature fluctuations, neuropsychiatric irritants, food intake, any external stimuli.

Coughing is especially severe in young children. Often attacks end with vomiting with the departure of a small amount of viscous sputum. Night attacks are particularly debilitating, accompanied by vomiting, spasms, apnea (breath-holding), the expert added.

Young children are at particular risk because of the possibility of prolonged periods of apnea, which can lead to hypoxia of the central nervous system and brain. Such conditions require urgent medical attention.

"Speaking about the effectiveness of pertussis vaccines, it is important to note the peculiarities of the traditional DPT vaccine. This vaccine had a number of significant disadvantages: firstly, it caused certain side effects, mainly related to the pertussis component, and secondly, the immunity formed was not always sufficiently persistent," said the infectious disease specialist.

According to him, modern vaccines, both Russian-made and foreign, demonstrate higher efficiency in the formation of immune response and provide more reliable protection.

"However, it should be recognized that even DPT does not guarantee full protection against pertussis infection. This is confirmed by the existence in Russian medical practice of the diagnosis "pertussis in the vaccinated"," the doctor added.

According to him, the most common complications of pertussis are secondary bacterial infections of various parts of the respiratory tract, among which a special place is occupied by pertussis pneumonia. However, no less dangerous complication is considered the development of apnea during spasmodic coughing. Patients with cardiovascular pathology, especially in neglected stages, deserve special attention. These patients, as a rule, are already in a state of chronic hypoxia, and any additional decrease in oxygen levels caused by apnea attacks during whooping cough can lead to serious consequences for their health.

Earlier, on February 1, Tatyana Simonova, a therapist at SberZdorovye medical company, said that the prevention of viral and infectious diseases is to follow a number of measures, among which is the organization of an optimal microclimate in the apartment. Physical activity is also important.