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Common Infectious Diseases

The following is a list of the most common infectious diseases throughout the world today. Accurate caseload numbers are difficult to determine, especially because so many of these diseases are endemic to developing countries, where many people do not have access to modern medical care. Approximately half of all deaths caused by infectious diseases each year can be attributed to just three diseases: tuberculosis, malaria, and AIDS. Together, these diseases cause over 300 million illnesses and more than 5 million deaths each year.

1. Cholera is a acute infection of the intestines spread mostly through contaminated drinking water and unsanitary conditions. It is endemic in the Indian subcontinent and sub-Saharan Africa. Its main symptom is copious diarrhea. Between 5% and 10% of those infected with the disease will develop severe symptoms, which also include vomiting and leg cramps. In its severe form, cholera can cause death by dehydration.

2. Approximately 2 billion people are infected with the Hepatitis B virus (HBV), making it the most common infectious disease in the world today. Over 350 million of those infected never rid themselves of the infection. Hepatitis is an inflammation of the liver that causes symptoms such as jaundice, extreme fatigue, nausea, vomiting, and stomach pain. Chronic infections can cause cirrhosis of the liver or liver cancer in later years.

3. Immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS) is a set of symptoms and infections resulting from the damage to the human immune system caused by the human immunodeficiency virus (HIV). This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to any infection. HIV is transmitted through direct contact with a bodily fluid containing HIV. AIDS is now a pandemic.

4. Malaria: Malaria is a mosquito-borne disease that is most common in tropical and subtropical climates and is found in 90 countries. Most of its victims are children. The first stage consists of shaking and chills, the next stage involves high fever and severe headache, and in the final stage the infected person's temperature drops and he or she sweats profusely. Malaria was almost eradicated 30 years ago; now it is on the rise again.

5. Measles: Measles is a disease that has seen a drastic reduction in countries where a vaccine is readily available, but it is still prevalent in developing countries. Symptoms include high fever, coughing, and a rash; common complications include diarrhea, pneumonia, and ear infections.

6. Meningitis is an infection of the spinal cord. It is usually the result of a viral or bacterial infection. Bacterial meningitis is more severe than viral meningitis and may cause brain damage, hearing loss, and learning disabilities. Symptoms include severe headache, fever, nausea, vomiting, lethargy, delirium, photophobia, and a stiff neck.

7. Tuberculosis causes nearly 2 million deaths every year, and it is estimates that nearly 1 billion people will be infected by 2020 if more effective preventive procedures are not adopted. The TB bacteria are most often found in the lungs, where they can cause chest pain and a bad cough that brings up bloody phlegm. Other symptoms include fatigue, weight loss, appetite loss, chills, fever, and night sweats.

8. Typhoid fever is usually spread through infected food or water. Symptoms include a sudden and sustained fever, severe headache, nausea, severe appetite loss, constipation, and sometimes diarrhea.