Diseases, Conditions, Syndromes

How diarrhea pathogens switch into attack mode at body temperature

Many bacterial pathogens excrete toxins as soon as they have entered the host in order to suppress its immune response. Researchers at Ruhr-Universität Bochum (RUB) have analyzed what happens on the molecular level when ...

Diseases, Conditions, Syndromes

Bacteria spread by ticks affected by humidity and mutual competition

Researchers at the University of Helsinki, the University of Zurich and the University of Exeter have carried out modelling on how environmental factors affect the occurrence of human-pathogenic bacteria found in the sheep ...

Immunology

Insights into a versatile molecular death switch

The enzyme caspase-8 induces a molecular cell death programme called pyroptosis without involving its enzymatic activity, a new study by Hamid Kashkar published in Nature shows. In order to safeguard healthy and functioning ...

Obstetrics & gynaecology

Infection likely cause of one in eight stillbirths

(HealthDay)—Most cases of infection-related stillbirth may be due to bacterial pathogens, according to a study published online Nov. 4 in Obstetrics & Gynecology.

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Pathogen

A pathogen (from Greek πάθος path "suffering, passion", and γἰγνομαι (γεν-) gignomai (gen-) "I give birth to"), infectious agent, or (more commonly) germ, is a biological agent that causes disease or illness to its host. There are several substrates and pathways whereby pathogens can invade a host; the principal pathways have different episodic time frames, but soil contamination has the longest or most persistent potential for harboring a pathogen.

The body contains many natural defenses against some of the common pathogens (such as Pneumocystis) in the form of the human immune system and by some "helpful" bacteria present in the human body's normal flora. However, if the immune system or "good" bacteria is damaged in any way (such as by chemotherapy, human immunodeficiency virus (HIV), or antibiotics being taken to kill other pathogens), pathogenic bacteria that were being held at bay can proliferate and cause harm to the host. Such cases are called opportunistic infection.

Some pathogens (such as the bacterium Yersinia pestis, which may have caused the Black Plague, the Variola virus, and the Maleria protozoa) have been responsible for massive numbers of casualties and have had numerous effects on afflicted groups. Of particular note in modern times is HIV, which is known to have infected several million humans globally, along with the Influenza virus. Today, while many medical advances have been made to safeguard against infection by pathogens, through the use of vaccination, antibiotics, and fungicide, pathogens continue to threaten human life. Social advances such as food safety, hygiene, and water treatment have reduced the threat from some pathogens.

Not all pathogens are negative. In entomology, pathogens are one of the "Three P's" (predators, pathogens, and parasitoids) that serve as natural or introduced biological controls to suppress arthropod pest populations.

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