Causes. A reduction over time in a region’s population can be caused by sudden adverse events such as outbursts of infectious disease, famine, and war or by long-term trends, for example sub-replacement fertility, persistently low birth rates, high mortality rates, and continued emigration.

The factors that slowed population growth in China until the 1300s were epidemics and warfare. China’s population had a growing tendency until the 1300s when a couple of factors reverse the tendency. One of them was epidemics.

The decline in U.S. population growth is likely due to a confluence of factors: lower levels of immigration, population aging, and declining fertility rates. A drop in net immigration to the United States is a key factor in the country’s declining population growth rate.

Birth rate, environment and government policy.

2 Population is growing rapidly, far outpacing the ability of our planet to support it, given current practices. Overpopulation is associated with negative environmental and economic outcomes ranging from the impacts of over-farming, deforestation, and water pollution to eutrophication and global warming.

In a closed population, birthrate and death rate are the only factors that affect the size of the population.

Two important measures of a population are population size, the number of individuals, and population density, the number of individuals per unit area or volume. Uniform means that the population is evenly spaced, random indicates random spacing, and clumped means that the population is distributed in clusters.

Intensity, duration of the causative agent determines the severity of disease. Body factors: Severity of disease also depends on the age, sex, gender, weight, race, comorbid conditions (coexisting diseases), habits (smoking) etc. Resistance:The Resistance of the human body system, immunization status.

It is the quantity of the disease causing microbes that determines the severity of disease manifestation. Our immune system is a major factor that determines the number of microbes surviving in the body.

Answer: The number of disease-causing microbes in the body decide the severity of disease manifestation. If the number of microbes is very small, the disease manifestations may be minor and even go unnoticed. But if the number of microbes is large, the disease can be severe.

Which two factors determine the severity of the diseases?

• Infection level, if infection is low than disease manifestation will also be less.
• Health status.
• Inflammatory responses.
• Level of the damage of the organ infected.

Signs and symptoms are abnormalities that can indicate a potential medical condition. Whereas a symptom is subjective, that is, apparent only to the patient (for example back pain or fatigue), a sign is any objective evidence of a disease that can be observed by others (for example a skin rash or lump).

While there are differences between signs and symptoms, they are both ultimately methods the body uses to communicate health problems and trigger the search for a solution. It is important not to ignore symptoms you discover by yourself or any signs found by a doctor.

A disease is any condition that causes discomfort, pain, distress or death to the person afflicted by it. A disease may be caused, by pathogens (virus, bacteria etc.) or, internally due to the failure of the immune system or a hormonal imbalance.

What does the word “syndrome” mean? Well, Webster’s Dictionary defines a syndrome as a group of signs and symptoms that occur together and characterize a particular abnormality or condition. Another definition is a set of concurrent things, such as emotions or actions, that form an identifiable pattern.

Disorder: Irregularity, disturbance, or interruption of normal functions. Syndrome: A number of symptoms occurring together and characterizing a specific disease.

Disability/Illness Description: CHARGE syndrome (or CHARGE Association) is a very rare disorder that includes people who share a specific set of challenges present at birth. The word “CHARGE” comes from the first letters of some of the most common features seen in these individuals.

Despite the high risk for Marfan related cardiovascular problems, the average life expectancy of those with Marfan syndrome is nearly 70 years. The life expectancy in this syndrome has increased to greater than 25% since 1972.

Study Patients. Their ages when the Marfan syndrome was first diagnosed ranged from 32 to 72 years (mean age, 46 years). Of these 28 patients, 7 were older than 50 years of age at the time of initial diagnosis.