In this Module we will explore communicable diseases. These are diseases that basically spread from one person to another or from an animal to a person. The spread often happens via airborne viruses or bacteria, but also through blood or other bodily fluid. The terms infectious and contagious are also used to describe communicable disease. We will learn about the most serious CDs (HIV/AIDS, Tuberculosis, Hepatitis, Malaria, Polio etc.) and what is being done on a global level to combat them.

At the end of this Module you should be able to articulate the following:

Critical Skills

1. Identify the most serious IDs in the world.

2. Describe the trend and distribution of these diseases globally.

3. Apply the concepts of social determinants of health to explain the persistence of the diseases in some countries.

4. Be able to identify the causes of CDs.

5. Understand and explain some of the programs/efforts being made to combat CDs.

6. Be familiar with at least two development organizations/NGOsand their work around CDs.

Communicable Diseases

As argued in Jacobsen (2014) and Merson et al (2012), collectively, CDs have undoubtedly been the single most important contributors to human morbidity and mortality throughout history. According to WHO(2008), more than 9.5 million people die each year due to infectious diseases, nearly all of whom live in low-and middle- income countries. Mortality attributable to CDs has declined in high-income countries. Merson et al (2012) discusses many CDs but as a summary I will highlight three serious IDs:

HIV/AIDS

HIV/AIDS is one of the serious CD the world faces. Human immunodeficiency virus (HIV) impairs the immune system of the people it infects. As the immune system weakens individuals become more at risk to infections. As condition progresses, the immune system becomes weaker and the individual becomes more at risk to acquired immunodeficiency syndrome (AIDS), the most advanced stage of HIV. According to WHO in 2009 close to 33million people were infected with HIV, with most of the cases (22 million) being in Sub-Saharan Africa. Many factors explain this high prevalence of HIV/AIDS in sub-Saharan Africa: Can you think of at least four causes? Although it is heavy in some parts of the world, HIV/AIDS has spread to almost every corner of the planet. People and their diseases are very mobile, making HVI/AIDS a concern of many countries. Because of the burden of disease associated with HIV/AIDS and its threat of continuing to affect other populations, the global health community is actively working to fight the HIV/AIDS epidemic on several levels:

• Education and outreach to stop the spread of HIV
• Research to develop new drugs to both prevent infection and address the symptoms of those already infected
• Support for children and families who have been affected through the loss of one or both parents

Some of the efforts have been successful. For example, because of advances in and availability of medicines (antiretroviral drugs), many people with HIV live for 15 years or more before symptoms of AIDS appear.According to WHO, close to 6.6 million people in low- and middle-income countries were receiving antiretroviral therapy (ART) for HIV/AIDS at the end of 2010. The U.S. President's Emergency Plan for AIDS Relief (PEPFAR) has been instrumental in making this possible. Many of the families in poor countries would not have benefited from these drugs were it not of programs that make them cheaper and available in these countries.
Hepatitis

Viral hepatitis is a major global health challenge. Viral hepatitis, which affects the liver, is a group of infections referred to as hepatitis A, B, C, D, and E. It is responsible for more than 1.4 million deaths annually, mostly in low- and middle- income countries. According to WHO, this public health threat rivals the annual number of deaths from HIV/AIDS (1.7 million), tuberculosis (1.4 million) and malaria (700,000). Worldwide, about 240 million people live with chronic HBV (Hepatitis B), 150 million people are chronically infected with hepatitis C virus, and there are about 1.4 cases of hepatitis A every year.

Major concern about viral hepatitis is hepatitis virus co-infection among people living with HIV, which can increase the risk of both serious liver disease and more rapidly progressive HIV infection. Thus health practitioners must pay close attention to viral hepatitis when implementing global programs on HIV/AIDS.

During World Hepatitis Day (28 July 2013) WHO and partners highlighted the fact that the burden of disease caused by viral hepatitis is growing, YET, little is being done about it. The question becomes are policymakers as well as health workers ignoring it or is it still largely unknown?

Here in the U.S. the government engages in multiple activities through various agencies and departments to prevent, fight, and treat hepatitis. Some of the agencies include: CDC, National Cancer Institute, National Institute on Drug Abuse, U.S Department of Veterans Affairs, and National Digestive Diseases Information Clearing House.

Tuberculosis (TB)

This is a disease caused by bacteria spread through the air from one person to another and affects mostly the lungs though it can also attack other parts of the body. Close to 33.3% of world population is estimated/believed to be infected with TB. TB can be latent, and persons with latent TB do not spread the disease unless it is active in the body.

Unfortunately, just as with many of the diseases, of all TB cases in the world, 85 percent occur in just 22 countries. Of these 22 countries, 9 are in sub-Saharan Africa and over 1.5 million cases of TB occur in Africa each year. Sub-Saharan Africa is really inflicted with a host of health issues - HIV/AIDS, TB, Malaria, poverty, poor SDH indicators etc. the convergence of such a host of diseases in one region increases chances of co-infections which make treating the diseases difficult. As you will learn from the cases for this Module, treatment failures result in drug resistance including multi-drug resistance. Actually, TB/HIV co-infections are a huge concern in Africa and are one of the main causes of morbidity and mortality.

According to the key findings of the WHO Global Health Tuberculosis Report 2012:

• TB care has increased substantially. In the past fifteen years 51 million people have been cured from TB and 20 million people have been saved from TB.

• There has been progress in expanding access to TB care, reducing cases and deaths, implementing collaborative TB/HIV activities, and developing new drugs and vaccines.

• TB death rate has dropped more than 40 percent between 1990 and 2011 and the incidence of TB has been decreasing by 2 percent each year

• Despite these improvements, the global burden of TB is still large.

• Critical funding gaps for TB care, control, research, and development still remain as well as slow progress in responding to multidrug-resistant TB (MDR-TB).

A note on Natural Disasters and CDs

Though there are many causes of CDs, natural disasters put those affected at a high risk of CDs. Natural disasters include earthquakes, volcanic eruptions, landslides, tsunamis, floods and drought. The potential impact of communicable diseases is often presumed to be very high in the chaos that follows natural disasters - think of the disruptions caused by the earthquake in Haiti, or the Japanese tsunami. Again, developing countries are disproportionately affected because of their lack of resources, infrastructure and disaster preparedness systems - hence in the case of a disaster they are at a higher risk of dealing with associated CDs.