Unit 1 Sanitation Microbiology.

I. Reading and Speaking Practice Section

1. Guess the meaning of the following international words:

microorganism, risks, virus, historic process, transportation, production, manufacture, regional, demonstrate, bacteria, climatic, result, helminthes, parasites, microscope.

2. Learn the names of pathogen representatives in English with their Russian equivalents:

Salmonella [`salmǝ`nelǝ] cальмонеллы

Picornaviruses [pi`koːrn ǝ` vairǝs ] пикорнавирусы

Rotaviruses [`rotǝ`vairǝs ] ротавирус

HEV hepatitis e virus

Trichophyton ]`trikǝfi`tan] грибок стригущего лишая

E. coli [i ː`kolai] кишечная палочка

Campylobacter [kampǝlǝ`baktǝr] иерсинии Nipah virus [`niːpǝ] вирус Нипах (новый зоонозный вирус,

который передается от животных чело- веку, вызывая тяжелое заболевание мозга) Giardia intestinalis [ʤi`aːr`diǝ] лямблия Cryptosporidium [`kriptǝspǝ`ridiǝm] криптоспоридия Toxoplasma gondii [`taːksǝ`plazmǝ] токсоплазма Trichuris trichuria [tri`kjurǝs] власоглав

Enteroviruses [`entǝrǝ `vairǝs ] энтеровирусы

Text A

Sanitation Microbiology:

Microbiological Hazards

Sanitation microbiology is a science concerned with the detection of risks associated with the production and consumption of food and water. It has been established that environmental factors determine the survival growth as well as the inactivation of microorganisms.

The types of microorganisms present will depend on the way the products have been developed, transported or prepared before eating or drinking. The guarantee of safe foods have an impact in economic, social and sanitary aspects of use.

Pathogen Groups

1. Viruses and Prions

A virus is a small infectious agent that can replicate only inside the living 

cells of an organism. Viruses can infect all types of organisms. The study of viruses is known as virology, a sub-speciality of microbiology. Virus particles (known as virions) consist of two or three parts: 1) the genetic material made from either DNA or RNA, long molecules that carry genetic information; 2) a protein

 coat that protects these genes; and in some cases 3) an envelope of lipids

 that surrounds the protein coat when they are outside a cell. The shapes of viruses range from simple helical  forms to more complex structures. Viruses spread in many ways; viruses in animals can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors. Viruses demonstrate considerable host specificity. Animal viruses with close human relatives, include some enteroviruses, picornaviruses and rota viruses, specific viruses such as HEV and Nipah viruses.

A prion is an infectious agent that is composed primarily of protein in a misfolded form. This would be in contrast to all other known infectious agents (virus/bacteria/fungus/parasite) which must contain nucleic acids. The word prion, coined in 1982 by Stanley B. Prusiner, is derived from the words protein and 

infection.

  Prions are responsible for the transmissible spongiform encephalopathies in a variety of mammals, including bovine spongiform encephalopathy(BSE, also known as "mad cow disease") in cattle.  All known prion diseases affect the structure of the brain or other neural tissue, and all are currently untreatable and are always fatal.

2.  Bacteria

Bacteria constitute a large domain of prokaryotic microorganisms. Bacteria have a wide range of shapes, ranging from spheres to rods and spirals. The study of bacteria is known as bacteriology, a branch of microbiology. If bacteria form a parasitic association with other organisms, they are classed as pathogens. Pathogenic bacteria are a major cause of infections such as tetanus, typhoid fever, diphtheria, syphilis, cholera, foodborne illness, leprosy and tuberculosis.  Bacteria cause   Johne's disease, mastitis, salmonella and anthrax in farm animals. There are several water borne zoonotic bacterial pathogens including Salmonella, E Coli, Campylobacter and Yersinia.. Bacteria are versatile . Their capacity to adapt to varying conditions is well known.

3  Fungi and Microsporidia

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds. Many fungi are parasites on plants, animals (including humans) Some fungi can cause serious diseases. Other fungi can attack eyes, nails, hair, and especially skin and cause local infections such as ringworm. Fungi are not normally considered as zoonotic water borne pathogens. However, there is a significant range of both yeasts and moulds that are zoonotic, including species of Trichophyton. These are generally transmitted by physical contact, ingestion or inhalation via credible waterborne routes.

The microsporidia constitute a phylum (Microspora) of spore-forming

 unicellular parasites. Microsporidia are restricted to animal hosts, Several species also infect humans. Four species of microsporidia have been found in a wide range of animals including humans Microsporidia are more likely to be fungi rather than protozoans.

4. Protozoa.

Protozoa are a diverse group of unicellular eukaryotic organisms, many of which are motile. In general, protozoa are referred to as animal-like protists because of movement (motility).  Protozoa such as the malaria parasites (Plasmodium spp.)

,trypanosomes and leishmania, are important disease causing . Protozoan infections in animals may be caused by organisms in the sub-class Coccidia (disease: Coccidiosis) and species in the genus Besnoitia (disease: Besnoitiosis) A number of water borne zoonotic protozoa exist such as Giardia intestinalis, Cryptosporidium and Toxoplasma gondii.

5 Helminthes

Parasitic worms, often referred to as helminths are a division of eukaryotic 

parasites.  They are worm-like organisms living in and feeding on living hosts, causing weakness and disease. Those that live inside the digestive tract are called intestinal parasites. They can live inside humans and other animals.

Helminthology is the study of parasitic worms and their effects on their hosts.

Zoonotic waterborne helminth infections, including those caused by Ascaris

lumbricoides and Trichuris trichuria, account for millions of human cases

world wide. There are also emerging helminthic parasites, some of which may

occasionally be transmitted by water from a zoonotic reservoir.

EXERCISES TO THE TEXT