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Stages of development of an infectious disease

Transmission of pathogens into the human body is referred to as infectioninfectioninfection. After infection, the disease incubation period occurs, in which viruses or bacteria multiply intensely and attack various organs. During this time, the germ carrier generally does not feel any symptoms. The first symptoms usually appear after a few days and are of general character, such as headaches, muscles, joints, chills, weakness, increased body temperature. Then, characteristic symptoms for a specific disease are revealed.

A runny nose and a strong cough mean respiratory tract infections. Gastrointestinal infections are often associated with nausea, vomiting and diarrhea. The symptoms of diseases such as smallpox and rubella are rashes, pimples and spots on the skin. Upon development of the characteristic symptoms, the doctor is able to make a medical diagnosis and commission appropriate medications. The time and course of the disease depends on the efficiency of the immune system, treatment methods used and the psychological attitude of the patient. Rest and positive thinking usually facilitate recovery and a return to full fitness.

The most susceptible to infection are people whose body is weakened by previous infections, excessive physical exertion, stress or improper diet associated with e.g. slimming, and chronically ill people.

Sources and ways of spreading infectious and parasitic diseases

Pathogenic agents can penetrate into the body through body orifices, mucous membranes and wounds. The germs permeate into these places in different ways.

One can get infected with numerous diseases by inhalation through the air. Infections of this type are referred to as droplet infections. In this way the following diseases are spread: flu, tuberculosis, smallpox, measles, diphtheria. The possibility of becoming infected with these diseases grows with the increase in the density of human communities. That is why the outbreaks of droplet‑borne diseases very often occur in kindergartens and schools.

Another way to spread the disease is oral exposure. Food and water consumed by humans may contain viruses, pathogenic bacteria, protozoa or parasitic eggs. This is how the following diseases are spread: tuberculosis, typhoid, hepatitis A, ascariasis, food poisoning. These diseases are sometimes referred to as the diseases of dirty hands, because the reason for their spread is the lack of hygiene in the preparation and consumption of meals.

Infectious agents may also permeate into the body through injured skin. A non‑sterile syringe or tattoo tool may also cause a risk of transferring such serious diseases as hepatitis B and C or HIV infection. Together with the soil, tetanus bacteria may get into the wound. In some cases, pathogens penetrate even through intact skin. Shaking hands with a patient with scabies poses a risk of parasite infection.

As a result of sexual intercourse syphilis and gonorrhoea pass through the mucous membranes of the reproductive organs, and protozoa, the same as vaginal trichomoniasis, as well as hepatitis HBV and HCV, human papillomavirus HPV and HIV are spreading.

Animals play a big role in the spread of infectious diseases. Flies can carry germs of typhoid fever and tuberculosis, and whipworm eggs from contaminated areas. Some ticks carry a dangerous and difficult to cure disease – borreliosis. Being bitten by an animal suffering from rabies can be dangerous for humans.

An infected person or animal in which pathogens multiply becomes a source of infection. A special kind of a source of infection are reservoir hostsreservoir hostreservoir hosts. These are people or animals in which, despite the presence of an infectious agent in the body, no symptoms of the disease are observed.

Summary

• Infectious diseases are caused by pathogenic organisms and spread through direct contact with the sick person, they can also be airborne, foodborne or sexually transmitted.

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Grafika przedstawiająca tablicę szkolną, na której znajdują się zdania do dokończenia. Finish selected sentences. 1 It was easy for me (uzupełnij). 2 It was difficult for me (uzupełnij). 3 Today I learned (uzupełnij). 4 I understood that (uzupełnij). 5 It surprised me (uzupełnij).

Grafika przedstawiająca tablicę szkolną, na której znajdują się zdania do dokończenia. Finish selected sentences. 1 It was easy for me (uzupełnij). 2 It was difficult for me (uzupełnij). 3 Today I learned (uzupełnij). 4 I understood that (uzupełnij). 5 It surprised me (uzupełnij).

How was this lesson? Did you like it? Finish selected sentences.

Keywords

contagious disease, infection

Glossary