Tuberculosis and HIV Co-infection - Epidemiology, Pathogenesis, and Treatment

Introduction

Tuberculosis (TB) is a serious infectious disease that can pose a threat to humans. If it occurs in HIV-infected individuals, the co-infection can pose certain diagnostic and prognostic challenges to the medical field. HIV-infected people are more prone to catch TB infection as compared to other people. It has been estimated that TB and HIV co-infection is one of the most common causes of death in people globally.

Tuberculosis and HIV (human immunodeficiency virus) comprise the majority of health problems in poor countries and developing nations. The prevalence rate is found to be very high worldwide. The co-infection exerts huge pressure on the healthcare system. Tuberculosis is caused by the bacterium Mycobacterium tuberculosis.

What Is the Epidemiology of Tuberculosis and HIV Co-infection?

• WHO (World Health Organization) has suggested that there are greater than 2 to 3 million deaths every year globally.

• The number of new infected active cases exceeds 10 million.

• The co-infection is mainly prevalent in the nations of Asia and Africa.

• There is a four to five times higher risk of acquiring TB infection in people who are in the early phase of HIV infection.

• The chances of encountering TB infection increase twenty times in advanced AIDS (Acquired Immunodeficiency Syndrome) cases.

• In patients receiving antiretroviral therapy, the risk is up to three to four times.

What Is the Cause of Tuberculosis and HIV Co-infection?

The human immunodeficiency virus threatens the host’s immune system in an infected individual. Since the immunity of the host deteriorates, the host’s body is not able to fight against other microbes like bacteria, parasites, fungi, and other viruses. As the infection progresses, the person enters into an advanced stage. This stage is known as AIDS (Acquired immunodeficiency syndrome).

On the other hand, tuberculosis occurs due to the infection of the bacterium Mycobacterium tuberculosis. This bacterium can invade the respiratory system along with other systems of the body, including the central and peripheral nervous system and the digestive system. It can also spread to the skin, bones, and other tissues. HIV-infected patients become more susceptible to TB infection because of the compromised immunity of the host. If left untreated, both infectious diseases might advance into severe states, thereby affecting the health of the body. They can compromise the organ functioning in the host, finally causing death.

What Is the Pathogenesis of Tuberculosis and HIV Co-infection?

• CD4+ T cells and macrophages are attacked by the HIV virus. Mycobacterium tuberculosis mainly invades the macrophages. Since there is a reduction in the number of CD4+ cells due to HIV, the macrophages are not able to eliminate the bacterial infection efficiently. As a result, there becomes a greater risk of being infected with TB infection in HIV patients.

• The macrophages are the cells that are mainly responsible for the phagocytosis of microbial pathogens. The killing of intracellular pathogens is also compromised due to the co-infection, thereby depleting the immune response of the individual.

• As the TB and HIV co-infection progresses, the overall health of the individual starts deteriorating.

• Also, TB is a chronic inflammatory infectious disease. Therefore, it aids in the deadly HIV virus propagation within more cells throughout the body. This can further worsen the condition of the patient.

• Therefore, in other words, it can be said that the two microbial pathogens potentiate each other. HIV co-infection is the most dangerous risk factor for TB.

• It is also thought that the HIV virus helps to reactivate the latent Mycobacterium tuberculosis infection in individuals.

What Are the Symptoms of Tuberculosis and HIV Co-infection?

It is difficult to diagnose the symptoms of TB in an HIV-infected person. However, some of the symptoms that can be present include:

• Chronic, persistent cough.

• Long-term fever with chills followed by night sweats.

• Feeling of weakness.

• Body malaise.

• Loss of appetite.

• Chest pain.

• Weight loss.

• Tiredness.

• Tender and swollen lymph nodes.

• Muscle and joint pain.

• Throat pain.

• Headaches.

• Rashes on the body.

• Nausea and vomiting.

How to Manage Tuberculosis and HIV Co-infection?

The affected person should receive medical care (HIV care) immediately as soon as he discovers the symptoms. It is very critical to start the treatment at once to prevent the worsening of the condition. It is important for healthcare workers to diagnose the infection at an early stage. Early identification of the infection would lead to a better prognosis.

WHO recommends the following measures:

• In individuals living with HIV, the search should be increased to quickly find TB-infected patients. Once the patients have been detected, treatment for TB should begin in these people.

• Isoniazid and Rifapentine medicines are usually self-administered for 12 weeks (once a week) for TB and HIV co-infection. This is the latest therapeutic regime being followed by doctors in patients who are on antiretroviral medications.

• In people diagnosed with TB, it is crucial to do an intense screening of all the probable and affected TB cases for HIV.

• For those who are diagnosed with co-infection, antiretroviral therapy is given along with Cotrimoxazole.

• Regular visits to the doctor are required for quick recovery.

How to Prevent Tuberculosis and HIV Co-infection?

• In order to prevent co-infection, follow-ups should be done regularly.

• Chest x-rays and sputum examinations should be done on a regular basis to identify TB infection in an HIV patient.

• The healthcare clinician usually recommends one Isoniazid tablet for a minimum period of six months to prevent the occurrence of TB infection in AIDS patients.

• Stay away from closed, unventilated places.

• TB vaccination (BCG vaccine) of an individual is an effective way of preventing the disease.

• Early and repeated screening of the patients is very important to prevent the disease.

• A facemask should be used in case of persistent coughing.

Conclusion

To conclude, tuberculosis and HIV co-infection is a serious condition that requires a comprehensive and coordinated approach to deal with. Though vaccination is available for TB, it is not effective enough to fight the co-infection. Therefore, researchers should discover a combination vaccine that could prevent the occurrence of co-infection. Better therapeutic and diagnostic methods should be incorporated into the healthcare system. Along with this, rapid and repeated screening of all HIV-infected people should be done to prevent further complications. Early treatment is important to minimize the mortality rate. If left untreated, the condition can become a dual epidemic, thereby increasing the number of deaths worldwide.