Infectious diseases are illnesses caused by the spread of microorganisms (bacteria, viruses, fungi or parasites) or prions to humans from other humans, animals or the environment, including food and water. Some infections are mild and barely noticeable, but others are severe and life-threatening, and some are resistant to treatment. Infection can be transmitted in a variety of ways. The immune system is an effective barrier against infectious agents, but colonies of pathogens may grow too large for the immune system to fight. At this stage, infections become harmful. Facts: Infection is the effect of a foreign organism in the body. Types of infection include bacterial, fungal, viral, protozoan, parasitic, and prion disease. They are classified by the type of organism causing the infection. Infections can range from mild inflammation in one person to an epidemic.

An autoimmune disorder occurs when the body's immune system attacks and destroys healthy body tissue by mistake. There are more than 80 types of autoimmune disorders. The blood cells in the body's immune system help protect against harmful substances. Examples include bacteria, viruses, toxins, cancer cells, and blood and tissue from outside the body. These substances contain antigens. The immune system produces antibodies against these antigens that enable it to destroy these harmful substances. When you have an autoimmune disorder, your immune system does not distinguish between healthy tissue and potentially harmful antigens. As a result, the body sets off a reaction that destroys normal tissues. The exact cause of autoimmune disorders is unknown. One theory is that some microorganisms (such as bacteria or viruses) or drugs may trigger changes that confuse the immune system. This may happen more often in people who have genes that make them more prone to autoimmune disorders.

Chronic respiratory diseases (CRDs) are diseases of the airways and other structures of the lung. Some of the most common are chronic obstructive pulmonary disease (COPD), asthma, occupational lung diseases and pulmonary hypertension. In addition to tobacco smoke, other risk factors include air pollution, occupational chemicals and dusts, and frequent lower respiratory infections during childhood. CRDs are not curable, however, various forms of treatment that help dilate major air passages and improve shortness of breath can help control symptoms and increase the quality of life for people with the disease.

A chronic disease is a condition you can control with treatment for months. Asthma, Cancer, Heart Diseases, Hepatitis, Kidney, Diabetes, HIV/AIDS and depression are common examples. Often, they don't have a cure, but you can live with them and manage their symptoms. Four of the most prominent chronic diseases – cardiovascular diseases (CVD), cancer, chronic obstructive pulmonary disease and type 2 diabetes – are linked by common and preventable biological risk factors, notably high blood pressure, high blood cholesterol and overweight, and by related major behavioural risk factors: unhealthy diet, physical inactivity and tobacco use. Action to prevent these major chronic diseases should focus on controlling these and other key risk factors in a well-integrated manner.

Alzheimer's disease is a type of dementia that causes problems with memory, thinking and behaviour. Symptoms usually develop slowly and get worse over time, becoming severe enough to interfere with daily tasks. The causes of dementia can vary, depending on the types of brain changes that may be taking place. Other dementias include Lewy body dementia, frontotemporal disorders, and vascular dementia. It is common for people to have mixed dementia—a combination of two or more types of dementia. For example, some people have both Alzheimer’s disease and vascular dementia.

Oral health is essential to general health and well-being at every stage of life. A healthy mouth enables not only nutrition of the physical body, but also enhances social interaction and promotes self-esteem and feelings of well-being. The mouth serves as a “window” to the rest of the body, providing signals of general health disorders. For example, mouth lesions may be the first signs of HIV infection, aphthous ulcers are occasionally a manifestation of Coeliac disease or Crohn’s disease, pale and bleeding gums can be a marker for blood disorders, bone loss in the lower jaw can be an early indicator of skeletal osteoporosis, and changes in tooth appearance can indicate bulimia or anorexia. The presence of many compounds (e.g., alcohol, nicotine, opiates, drugs, hormones, environmental toxins, antibodies) in the body can also be detected in the saliva. Oral conditions have an impact on overall health and disease. Bacteria from the mouth can cause infection in other parts of the body when the immune system has been compromised by disease or medical treatments (e.g., infective endocarditis). Systemic conditions and their treatment are also known to impact on oral health (e.g., reduced saliva flow, altered  balance of oral microorganisms).

Crohn's disease is a chronic, or long-term, condition that causes inflammation of the digestive tract. It is a type of inflammatory bowel disease. Crohn's disease can be painful, debilitating, and, sometimes, life-threatening. Crohn's disease, also called ileitis or enteritis, can affect any part of the gut, from the mouth all the way down to the anus. In the majority of cases, however, the lower part of the small intestine - the ileum - is affected. Epilepsy is a chronic noncommunicable disease of the brain that affects around 50 million people worldwide. It is characterized by recurrent seizures, which are brief episodes of involuntary movement that may involve a part of the body (partial) or the entire body (generalized) and are sometimes accompanied by loss of consciousness and control of bowel or bladder function. Seizure episodes are a result of excessive electrical discharges in a group of brain cells. Different parts of the brain can be the site of such discharges. Seizures can vary from the briefest lapses of attention or muscle jerks to severe and prolonged convulsions. Seizures can also vary in frequency, from less than 1 per year to several per day.

Rheumatic diseases affect your joints tendons, ligaments, bones, and muscles. Among them are many types of arthritis, a term used for conditions that affect your joints. Sometimes they’re called musculoskeletal diseases. Common symptoms include: Joint pain Loss of motion in a joint or joints, Inflammation swelling, redness, and warmth in a joint or affected area. Orthopedists use medical, physical and rehabilitative methods as well as surgery and are involved in all aspects of heath care pertaining to the musculoskeletal system. It is a specialty of incredible breadth and variety. Orthopedists treat a immense variety of diseases and conditions, including fractures and dislocations, torn ligaments, sprains and strains tendon injuries, pulled muscles and bursitis ruptured disks, sciatica, low back pain, and scoliosis knock knees, bow legs, bunions and hammer toes, arthritis and osteoporosis, bone tumors, muscular dystrophy and cerebral palsy, club foot and unequal leg length abnormalities of the fingers and toes, and growth abnormalities. In general, orthopedists are skilled in the: Diagnosis of your injury or disorder, Treatment with medication, exercise, surgery or other treatment plans, Rehabilitation by recommending exercises or physical therapy to restore movement, strength and function, Prevention with information and treatment plans to prevent injury or slow the progression of diseases. 

Angiology is the medical specialty which studies the diseases of the circulatory system and of the lymphatic system, i.e., arteries, veins and lymphatic vessels, and its diseases. Allergies are an abnormal and specific reaction of the immune system and with regard to substances foreign to the body, the allergens. The allergens can be of various kinds: pollen, dust, mold, food, occupational agents, mites, insect venom, animal fur. In allergic subjects, allergens induce the production of antibodies of the IgE type that, during exposure to allergens, causing the release of various substances by certain immune system cells, mast cells and basophils. The main substance released during exposure to the allergens is histamine. It induces an excessive reaction of the blood vessels and smooth muscle tissue and then the appearance of allergic symptoms that varies depending on the part of the body involved.

Chronic disease epidemiology unit addresses the etiology, prevention, distribution, natural history, and treatment outcomes of chronic health disorders, including cancer (particularly breast, colon, lung, prostate, ovary and pancreas), cardiovascular disease, diabetes, gastrointestinal and pulmonary disease, and obesity. Host, pathogen and environmental factors are monitored to determine the dynamics of infection, the ultimate goal of which is to devise intervention strategies. Molecular methods, such as phylogenomics, can be used to accurately track pathogens. Infectious diseases can cause many different symptoms. Some are so mild that you may not even notice any symptoms, while others can be life-threatening. There are treatments for some infectious diseases, but for others, such as some viruses.

Non-communicable diseases (NCDs) include diseases which are not infectious. Such diseases mainly result from life-style related factors such as unhealthy diet, lack of physical activity, tobacco use, etc. Changes in life-styles, behavioural patterns, demographic profile (ageing population), socio-cultural and technological advancements are leading to sharp increase in the prevalence of Non-Communicable Diseases like Diabetes, Cardiovascular diseases, Stroke, Cancer, etc. These diseases can be prevented by making simple changes in the way we live their out or simply by changing our life-style. One of the most serious concerns is that it affects people in their most productive years of life. It is, therefore, vital that increasing importance of chronic diseases is anticipated and acted upon urgently. NCDs have emerged as a major public health problem in recent years.