Infectious Diseases

An infectious disease is a clinically evident disease resulting from the presence of pathogenic microbial agents, including viruses, bacteria, fungi, protozoa, multicellular parasites and aberrant proteins known as prions. These pathogens are able to cause disease in animals and/or plants.

Infectious pathologies are usually qualified as contagious diseases (also called communicable diseases) due to their potentiality of transmission from one person or species to another. Transmission of an infectious disease may occur through one or more of diverse pathways including physical contact with infected individuals. These infecting agents may also be transmitted through liquids, food, body fluids, contaminated objects, airborne inhalation, or through vector-borne spread.

An infection however, is not synonymous with an infectious disease, as an infection may not cause important clinical symptoms or impair host function.

AIDS/HIV

Human immunodeficiency virus, or HIV, is the retrovirus that causes acquired immune deficiency syndrome (AIDS). The syndrome was first recognized in 1981. The virus weakens a person's ability to fight infections and cancer. People with HIV are said to have AIDS when they develop certain infections or cancers or when their CD4 count is less than 200. CD4 count is determined by a blood test in a doctor's office.

Having HIV does not always mean that you have AIDS. It can take many years for people with the virus to develop AIDS. HIV and AIDS cannot be cured. An entire HIV regimen that was once complex, involving multiple agents (20 to 40 pills and capsules) taken at different times of the day is now as compact and simple as one pill, once a day. Twenty-five percent of individuals in the US with HIV do not know their status. They often present very late in disease. There are over 40,000 new infections annually in the U.S.. The HIV positive but unaware individuals account for about 54 to 70 percent of the new infections. The Centers for Disease Control recognizes the significant benefits to an individual in terms of decreased morbidity and mortality when therapy is initiated earlier in disease and the potential to reduce ongoing HIV transmission. The CDC now recommends that HIV testing be incorporated into routine health care for all individuals.

Cholera

Cholera is an acute infectious disease caused by the bacterium Vibrio cholerae, which lives and colonizes in the small intestine but does not destroy or invade the intestinal tissue. The major symptom of cholera is massive watery diarrhea that occurs because the bacteria’s toxin stimulates the small intestine to secret fluid. There are several strains of V. cholerae and the severity of the disease is based on the particular infectious strain. Cholera is not a difficult disease to treat and most people recover well with hydration. However, if the disease goes untreated, it can rapidly lead to shock, as a result of fluid and electrolyte loss and to life-threatening complications.