Infectious diseases are the most common types of diseases. According to statistics, every person has an infectious disease at least once a year. The reason for this prevalence of these diseases lies in their diversity, high infectiousness and resistance to external factors.
Classification of infectious diseases
The classification of infectious diseases according to the mode of transmission of infection is widespread: airborne, fecal-oral, domestic, transmissible, contact, transplacental. Some of the infections can be related to different groups at the same time, because they can be transmitted in different ways. In the place of localization, infectious diseases are divided into 4 groups:
- Infectious intestinal diseases, in which the pathogen lives and multiplies in the intestine. The diseases of this group include: salmonellosis, typhoid fever, dysentery, cholera, botulism.
- Infections of the respiratory system, in which the mucous membrane of the nasopharynx, trachea, bronchi and lungs is affected. This is the most common group of infectious diseases, which causes epidemic situations every year. This group includes: ARVI, a variety of types of influenza, diphtheria, chicken pox, angina.
- Skin infections transmitted through touch. This includes: rabies, tetanus, anthrax, erysipelas.
- Infections of the blood, transmitted by insects and through medical manipulation. The causative agent lives in lymph and blood. To blood infections include: typhus, plague, hepatitis B, encephalitis.
Features of infectious diseases
Infectious diseases have common features. In different infectious diseases, these features manifest themselves in varying degrees. For example, the variability of chicken pox can reach 90%, and immunity is formed for life, while the infectiousness of ARVI is about 20% and forms a short-term immunity. Common for all infectious diseases are such features:
- Infectiousness, which can cause epidemic and pandemic situations.
- The cyclicity of the course of the disease: the incubation period, the appearance of harbingers of the disease, the acute period, the recession of the disease, recovery.
- Common symptoms include fever, general malaise, chills, headache.
- Formation of immune defense in relation to the disease.
Causes of infectious diseases
The main cause of infectious diseases are pathogens: viruses, bacteria, prions and fungi, however, in all cases, the entry of a harmful agent leads to the development of the disease. In this case, such factors will be important:
- what infectious diseases are infectious;
- how many agents got into the body;
- what is the toxicity of the microbe;
- what is the general state of the body and the state of the human immune system.
Periods of infectious disease
From the time the pathogen enters the body and until complete recovery takes some time. During this period a person passes through such periods of an infectious disease:
- The incubation period is the interval between the entry of a harmful agent into the body and the beginning of its active action. This period ranges from several hours to several years, but is usually 2-3 days.
- The prodormal period is characterized by the appearance of symptoms and blurred clinical picture.
- The period of the development of the disease , in which the symptoms of the disease are amplified.
- A period of heat , in which the symptoms are expressed as brightly as possible.
- The period of extinction - symptoms decrease, the condition improves.
- Exodus. Often it is recovery - the complete disappearance of signs of the disease. The outcome can also be different: transition to a chronic form, death, relapse.
The spread of infectious diseases
Infectious diseases are transmitted in such ways:
- Air-drip - when sneezing, coughing, when particles of saliva with a microbe are inhaled by a healthy person. In this way, there is a massive spread of infectious disease among people.
- Fecal-oral - microbes are transmitted through contaminated foods, dirty hands.
- Subject - the transmission of infection occurs through household items, dishes, towels, clothes, bed linens.
- The transmissible source of infection is an insect.
- Contact - transmission of infection occurs through sexual contact and infected blood.
- Transplacental - the infected mother transmits the infection to the baby in utero.
Diagnosis of infectious diseases
Since the types of infectious diseases are manifold and numerous, physicians have to apply a complex of clinical and laboratory-instrumental methods of research to establish the correct diagnosis. At the initial stage of diagnosis, an important role is played by the collection of anamnesis: the history of previous diseases and this, the conditions of life and work. After the examination, making an anamnesis and setting the initial diagnosis, the doctor prescribes a laboratory study. Depending on the expected diagnosis, it can be different blood tests, cell tests and skin tests.
Infectious Diseases - List
Infectious diseases are the leaders among all diseases. The causative agents of this group of diseases are various viruses, bacteria, fungi, prions and parasites. The main infectious diseases are diseases that have a high degree of infectiousness. The most common are such infectious diseases:
- infections of the lower respiratory tract;
- intestinal diseases;
- ARVI;
- HIV;
- tuberculosis;
- Hepatitis B;
- dysentery ;
- candidiasis;
- toxoplasmosis;
- salmonellosis.
Bacterial diseases of man - list
Bacterial diseases are transmitted through infected animals, a sick person, contaminated foods, objects and water. They are divided into three types:
- Intestinal infections. Especially common in the summer. Caused by bacteria of the genus Salmonella, Shigella, E. coli. Intestinal diseases include: typhoid fever, paratyphoid, food toxicoinfection, dysentery, escherichiosis, campylobacteriosis.
- Respiratory tract infections. They are localized in the respiratory organs and can be complications of viral infections: FLU and ARVI. Bacterial infections of the respiratory tract are: angina, tonsillitis, sinusitis, tracheitis, epiglottitis, pneumonia.
- Infections of the outer integument caused by streptococci and staphylococci. The disease can occur due to the ingress of harmful bacteria to the skin from the outside or due to a violation of the balance of skin bacteria. To infections of this group are: impetigo, carbuncles, furuncles, erysipelas.
Viral diseases - list
Human viral diseases are highly infectious and prevalent. The source of the disease is a virus transmitted from a sick person or animal. Infectious disease agents spread rapidly and can reach people on a vast territory, leading to epidemic and pandemic situations. They manifest themselves fully in the autumn-spring period, which is associated with weather conditions and weakened people's organisms. The ten most common infections include:
- ARVI;
- influenza ;
- rabies;
- chickenpox;
- viral hepatitis;
- cytomegalovirus infection ;
- herpes simplex;
- Infectious mononucleosis;
- rubella;
- viral pneumonia .
Fungal diseases
Fungal infectious diseases of the skin are transmitted by direct contact and through contaminated objects and clothing. Most fungal infections have similar symptoms, so a diagnosis of skin scrapings is required to clarify the diagnosis. Common fungal infections include:
- candidiasis;
- keratomycosis: lichen and trichosporia;
- dermatomycosis: mycosis, favus;
- pyoderma : furunculosis, ulcers;
- exanthema: papilloma and herpes.
Protozoal diseases
Protozoal diseases are diseases caused by parasitic protozoa. Among the protozoal diseases are common: amoebiasis, giardiasis, toxoplasmosis and malaria. The carriers of the infection are domestic animals, livestock, malarial mosquitoes, flies of Tzece. Symptoms of these diseases are similar to intestinal and acute viral diseases, but in some cases the disease can go without symptoms. To clarify the diagnosis, laboratory diagnosis of feces, blood smears or urine is necessary.
Prion diseases
Among the prion diseases, some of the diseases are infectious. Prions, proteins with a changed structure, penetrate the body together with contaminated food, through dirty hands, non-sterile medical instruments, contaminated water in reservoirs. Prion infectious diseases of people are serious infections that practically do not lend themselves to treatment. These include: Creutzfeldt-Jakob disease, kuru, fatal familial insomnia, Gerstman-Straussler-Sheinker syndrome. Prion diseases affect the nervous system and the brain, leading to dementia.
The most dangerous infections
The most dangerous infectious diseases are diseases in which the chance to recover is a fraction of a percent. The five most dangerous infections include:
- Kreutzfeldt-Jakob disease, or spongiform encephalopathy. This rare prion disease is transmitted from animal to human, leads to brain damage and death.
- HIV. The virus of immunodeficiency is not fatal until it has passed to the next stage - AIDS .
- Rabies. Curing of the disease is possible by vaccination, until the symptoms of rabies have appeared. The appearance of symptoms indicates an imminent death.
- Hemorrhagic fever. This includes a group of tropical infections, among which are heavily diagnosed and not treatable.
- Plague. This disease, which once mouthed whole countries, is now rare and can be treated with antibiotics. Only some forms of plague are lethal.
Prevention of infectious diseases
Prevention of infectious diseases consists of such components:
- Enhance the body's defenses. The stronger the immunity of a person, the less often he will get sick and heal faster. To do this, it is necessary to lead a healthy lifestyle, eat right, play sports, fully rest, try to be optimistic. A good effect for improving immunity is hardening.
- Vaccination. In the period of epidemics, a positive result gives an aiming vaccination against a specific fever. Vaccinations against certain infections (measles, mumps, rubella, diphtheria, tetanus) are included in the mandatory vaccination schedule.
- Contact protection. It is important to avoid infected people, use protective individual means during epidemics, often wash their hands.