Microbiology

Microbiology Study Guide

Clinical and Subclinical Disease A clinical disease is a disease in which the signs and symptoms are explicitly visible and are enough to substantiate the onset of disease. In contrast, subclinical diseases are ones in which the process of disease has been initiated, but the symptoms and signs are not visible. Types of Diseases Communicable and Non-Communicable Disease Diseases can be differentiated on the basis of communicable and non-communicable. Communicable diseases are contagious and can be transmitted from one person to another. Communicable diseases generally result from an infection and the pathogenic agents that reside in the individual host organism are transmitted to infect others. For instance, the common cold and chickenpox are communicable diseases. In contrast, non-communicable diseases are diseases that are not contagious and are not transmitted from one person to another. These diseases are non-infectious in nature. For instance, heart diseases, kidney ailments, cancer, asthma, diabetes, osteoporosis, etc., are some examples of non- communicable diseases. The duration of the non-communicable disease is long and grows slowly. Endemic, Epidemic, and Pandemic Diseases Infections can be endemic, epidemic, and pandemic. An infection is said to be endemic when the entire population suffers from the same disease and the infection is not injected from any outside source. For instance, in the UK, chickenpox is endemic. An epidemic disease is one which is not generally maintained in the population, but new cases of the disease erupt at a higher rate than the one observed during the previous experience. The outbreak of a disease is known as epidemic. The pandemic disease is the kind of epidemic infection that affects a vast population of human beings, such as spreading across many nations, continents, or even affecting most of the world population. Acute and Chronic Diseases A disease can either be acute or chronic. Disease is said to be acute when it begins suddenly or when it occurs for a short time period. In contrast, the disease is said to be chronic when the infection or disease persist for a considerably longer time period. Primary and Secondary Diseases Primary disease is a disease that is not affected or caused by any previous historical ailment, while secondary disease is a disease that is caused as a consequence of the primary disease. For instance, under normal circumstances, catching the flu is a primary disease, but if the flu caused one to have strep throat due to the predisposition of a bacterial infection, it is known as a secondary disease.

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