Communicable diseases in India: tuberculosis and lower respiratory infections
Part of the double burden of respiratory disease in India is caused by communicable diseases. Communicable diseases are developed after infection, which can be transmitted between animals and people. The World Health Organization (WHO) stated that infectious diseases are now spreading faster than ever.
Within the communicable diseases, this blog will be focusing on communicable diseases affecting the respiratory system. Numerous communicable diseases affect the respiratory system, such as COVID-19, influenza, measles, chickenpox, tuberculosis (TB) and lower respiratory infections. Currently, the most prevalent communicable diseases in India are the respiratory disease & TB (figure 1). Therefore, this blog will focus on the last two communicable diseases affecting the respiratory system, tuberculosis and lower respiratory infections.
Figure 1: The ranking of causes of the burden of disease in India from 1990 to 2019
Tuberculosis (TB) in India
As of 2019, 2.64 million people in India (193 per 100 000 persons) are infected with TB. Tuberculosis is caused by the Mycobacterium tuberculosis and can be found in multiple parts of the body such as the lungs, heart and the vertebrae. We will be talking about pulmonary tuberculosis, which affects the lungs and occurs 55% of the time, according to the Dutch National Institute for Public Health and the Environment.
Picture 1: The spread of tuberculosis (TB)
Tuberculosis spreads through the air between different people, through coughing, breathing or speaking (picture 1). When someone breathes in the contaminated air, they can become infected by the tuberculosis bacteria. There are multiple risk factors that increase the tuberculosis hazard, such as HIV, nutrition, smoking and diabetes mellitus.
Certain symptoms that can occur when someone is infected by TB, are coughing (blood), sputum, breathlessness, persistent fever, fatigue, weight loss and night sweats. The diagnosis of a person with TB in India can be confirmed by examining a smear of sputum, chest radiography (X-ray) or the CB-NAAT test. The latter is a molecular test for TB and also shows if the patient is drug-resistant.
To prevent someone from getting infected with the TB, they can be vaccinated with the BCG vaccine. If someone is infected, tuberculosis can be treated by multiple antimicrobial drug therapy over a course of 6 months. However, if someone is infected by multidrug-resistant tuberculosis (MDR-TB) this may take up to 20 months. Antimicrobial resistance in the case of tuberculosis will be explained in a separate blog post.
Lower respiratory diseases in India
Lower respiratory infections contribute to the leading cause of mortality and morbidity among infants and children under five year in developing countries. There are about 12 million under-five hospitalizations and 1–2 million deaths worldwide due to LRIs. In India , 17% of the deaths in children under 5 years are due to pneumonia, which is the most common cause of mortality associated with LRIs. Research has shown that the direct costs of an LRI- hospitalizations in India are 34% of the per capita income per year, as can be seen LRIs, have a high economic and disease burden.
LRIs include pneumonia, bronchiolitis and bronchitis. Pathogens of LRIs can be bacteria or viruses. Viruses mostly cause bronchiolitis and bronchitis. The most common bacterial agent in community-acquired pneumonia is Streptococcus pneumoniae. Agents that cause atypical pneumonias are Chlamydia spp, Coxiella burnetti, Legionella and Mycoplasma pneumoniae.
The pathogen enters the distal airway by aspiration, inhalation or hematogenous seeding. Then the organism multiplies on or in the epithelium, which leads to increased mucus secretion, impaired mucociliary function and inflammation. In severe bronchiolitis, necrosis and inflammation of the epithelium could block small airways resulting in airway obstruction. Risk factors associated with LRIs are low birth weight, malnutrition, poverty, overcrowding, inadequate breastfeeding, indoor and outdoor air pollution.
The symptoms of LRIs include fever, cough, chest pain, sputum production and tachypnea. Patients who have pneumonia could also experience non-respiratory symptoms like headache, abdominal pain, vomiting, confusion, myalgia, diarrhea and nausea.
For most of the viral infections a symptomatic treatment is used and for bacterial pneumonia antibacterial is used. It is recommended for people with high risk to vaccinate against 23 serotypes of Streptococcus pneumoniae.
This blog post was co-written by Caitlin MacMillan Maartens and Charmain Kemper
