Respuesta :
Answer:
The agents which cause disease are called pathogens. They fall into five groups: bacteria, fungi, virus, protozoa, algal and new class of pathogens prions.The FDA lists over 40 types of bacteria, viruses, parasites, and fungi that contaminate foods and cause illness, but they have singled out 6 that are the most contagious and cause the most severe symptoms. They are E coli, Hepatitis A, Nontyphoidal Salmonella, Norovirus, Shigella, Salmonella Typhi
Explanation:
- Bacteria:Bacteria can often be killed by antibiotics, which are usually designed to destroy the cell wall. This expels the pathogen's DNA, making it incapable of producing proteins and causing the bacteria to die. A class of bacteria without cell walls is mycoplasma (a cause of lung infections). A class of bacteria which must live within other cells (obligate intracellular parasitic) is chlamydia (genus), the world leader in causing sexually transmitted infection (STI).Pathogenic bacteria also cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy.
- Virus :Some of the diseases that are caused by viral pathogens include smallpox, influenza, mumps, measles, chickenpox, ebola, and rubella. Pathogenic viruses are diseases mainly of the families of: Adenoviridae, Picornaviridae, Herpesviridae, Hepadnaviridae, Flaviviridae, Retroviridae, Orthomyxoviridae, Paramyxoviridae, Papovaviridae, Polyomavirus, Rhabdoviridae, Togaviridae. Viruses typically range between 20 and 300 nanometers in length .
- Fungi: Fungi comprise a eukaryotic kingdom of microbes that are usually saprophytes (consume dead organisms) but can cause diseases in humans, animals and plants. Fungi are the most common cause of diseases in crops and other plants. The typical fungal spore size is 1–40 micrometers in length.
- Prions:According to the prion theory, prions are infectious pathogens that do not contain nucleic acids. These abnormally folded proteins are found characteristically in some diseases such as scrapie, bovine spongiform encephalopathy (mad cow disease) and Creutzfeldt–Jakob disease
- Protozoa:Some eukaryotic organisms, including a number of protozoa and helminths, are human parasites (i.e., they cause various infectious diseases.(eg. Amoeba and Paramoecium)
- Algal :Examples of algae acting as a mammalian pathogen are known as well, notably the disease protothecosis. Protothecosis is a disease found in dogs, cats, cattle, and humans caused by a type of green alga known as prototheca that lacks chlorophyll.
