Infectious diseases in the context of "Preventive healthcare"

Preventive healthcare, or prophylaxis, is the application of healthcare measures to prevent diseases. Disease and disability are affected by environmental factors, genetic predisposition, disease agents, and lifestyle choices, and are dynamic processes that begin before individuals realize they are affected. Disease prevention relies on anticipatory actions that can be categorized as primal, primary, secondary, and tertiary prevention.

Each year, millions of people die of preventable causes. A 2004 study showed that about half of all deaths in the United States in 2000 were due to preventable behaviors and exposures. Leading causes included cardiovascular disease, chronic respiratory disease, unintentional injuries, diabetes, and certain infectious diseases. This same study estimates that 400,000 people die each year in the United States due to poor diet and a sedentary lifestyle. According to estimates made by the World Health Organization (WHO), about 55 million people died worldwide in 2011, and two-thirds of these died from non-communicable diseases, including cancer, diabetes, and chronic cardiovascular and lung diseases. This is an increase from the year 2000, during which 60% of deaths were attributed to these diseases.)

Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and many are beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are considered part of the gut flora, with a few hundred species present in each individual human's digestive tract.

The body is continually exposed to many species of bacteria, including beneficial commensals, which grow on the skin and mucous membranes, and saprophytes, which grow mainly in the soil and in decaying matter. The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms.

Infant mortality is the death of an infant before the infant's first birthday. The occurrence of infant mortality in a population can be described by the infant mortality rate (IMR), which is the number of deaths of infants under one year of age per 1,000 live births. Similarly, the child mortality rate, also known as the under-five mortality rate, compares the death rate of children up to the age of five.

In 2013, the leading cause of infant mortality in the United States was birth defects. Other leading causes of infant mortality include birth asphyxia, pneumonia, neonatal infection, diarrhea, malaria, measles, malnutrition, term birth complications such as abnormal presentation of the fetus, umbilical cord prolapse, or prolonged labor. One of the most common preventable causes of infant mortality is smoking during pregnancy. Lack of prenatal care, alcohol consumption during pregnancy, and drug use also cause complications that may result in infant mortality. Many situational factors contribute to the infant mortality rate, such as the pregnant woman's level of education, environmental conditions, political infrastructure, and level of medical support. Improving sanitation, access to clean drinking water, immunization against infectious diseases, and other public health measures can help reduce rates of infant mortality.

Hygiene is a set of practices performed to preserve health.According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refers to maintaining the body's cleanliness. Hygiene activities can be grouped into the following: home and everyday hygiene, personal hygiene, medical hygiene, sleep hygiene, and food hygiene. Home and every day hygiene includes hand washing, respiratory hygiene, food hygiene at home, hygiene in the kitchen, hygiene in the bathroom, laundry hygiene, and medical hygiene at home.

Many people equate hygiene with "cleanliness", but hygiene is a broad term. It includes such personal habit choices as how frequently to take a shower or bath, wash hands, trim fingernails, and wash clothes. It also includes attention to keeping surfaces in the home and workplace clean, including bathroom facilities. Adherence to regular hygiene practices is often regarded as a socially responsible and respectable behavior, while neglecting proper hygiene can be perceived as unclean or unsanitary, and may be considered socially unacceptable or disrespectful, while also posing a risk to public health.

Climate change affects human health in many ways, including an increase in heat-related illnesses and deaths, worsened air quality, the spread of infectious diseases, and health risks associated with extreme weather such as floods and storms. Rising global temperatures and changes in weather patterns are increasing the severity of heat waves and extreme weather events. These events in turn have direct and indirect impacts on human health. For example, when people are exposed to higher temperatures for longer time periods they might experience heat illness and heat-related death.

In addition to direct impacts, climate change and extreme weather events cause changes in biomes. Certain diseases that are carried and spread by living hosts such as mosquitoes and ticks (known as vectors) may become more common in some regions. Affected diseases include dengue fever and malaria. Contracting waterborne diseases such as diarrhoeal disease will also be more likely.

In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire continent. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent. Outbreaks include many epidemics, which is a term normally only used for infectious diseases, as well as diseases with an environmental origin, such as a water or foodborne disease. They may affect a region in a country or a group of countries. Pandemics are near-global disease outbreaks when multiple and various countries around the Earth are soon infected.

Typhus, also known as typhus fever, is a group of infectious diseases that include epidemic typhus, scrub typhus, and murine typhus. Common symptoms such as fever, headache, and a rash typically begin one to two weeks after exposure.

The diseases are caused by specific types of bacterial infection. Epidemic typhus is caused by Rickettsia prowazekii spread by body lice, scrub typhus is caused by Orientia tsutsugamushi spread by chiggers, and murine typhus is caused by Rickettsia typhi spread by fleas.