Types of Infectious Diseases

The human body is susceptible to a variety of different diseases, many of which are infectious. These diseases are often treatable by a physician, but not all of them are curable. They are often caused by viral, fungal, protozoan or bacterial infections. These infections can be transmitted person-to-person or animal-to-person.

Influenza

Influenza is more commonly known as the flu. It is an extremely contagious viral infection and most often occurs during the winter months. It affects the upper respiratory system and is characterized by muscle aches, non-productive coughing, a sore throat and fever. For most people, influenza resolves within several days, but for some it may also lead to death. It is an airborne disease that is passed from one person to the other either by coughing or sneezing. It can live on objects for a period of time, which makes it easy to contract the illness from items such as doorknobs and keyboards. It is recommended that children, the elderly and people with compromised immune systems should get vaccinated with the flu shot yearly. However, the efficacy of the vaccine depends on the strain of flu that is currently circulating during any given year.

Infectious Mononucleosis

Infectious mononucleosis, or mono, is commonly referred to as the kissing disease. It is caused by the Epstein-Barr virus, which is a type of herpes virus. Symptoms of the infection are sore throat, fatigue and fever. It is most often diagnosed in adolescents, primarily ages 15 to 17. It is spread by direct person-to-person contact, most often through a transfer of saliva from kissing, but it may also be spread by sneezing or coughing.

West Nile Virus

The West Nile virus is a flavivirus that is spread by mosquitoes. In addition to affecting humans it also can affect other mammals such as horses. Signs of West Nile are similar to having the flu and include fever, body aches, headaches, skin rashes and swollen lymph glands. Extreme cases can result in serious and even life-threatening illnesses, such as inflammation of the brain. There may also be long-term effects of the disease such as depression, some memory loss and irritability. The first case of the West Nile virus in the United States occurred in New York in 1999. Incidences can occur year round in southern climates and during the late summer and early fall in more temperate zones. The death rate ranges between 3 to 15 percent.