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C R E A T I N G A N D D E L I V E R I N G B E T T E R S O L U T I O N S Water Microbiology Presented by Gilles Wendling, Ph.D., P.Eng. E B A E N G I N E E R I N G C O N S U L T A N T S L T D .
Outline • Why should we be concerned? • Brief history • What is the problem • Status in BC • Outbreaks and pathogenes • Bacteria and viruses • Definition • Characteristics • Other waterborne • Algae and fungi • Symptoms and illnesses • What can we do about it? • treatment
Treatment: started ~100 years ago • Began in early 1900’s in England (1908 in Chicago and Jersey City) • Continuous application of chlorine • Waterborne disease such as typhoid fever was prevalent. • Major cities were suffering 100 or more typhoid deaths a year per 100,000 persons. • 1910 – 1920: thousands of drinking water treatment plants initiated chlorine disinfection • The typhoid death rate fell simultaneously.
Treatment (cont’d) • The number of typhoid fever cases is now insignificant • In developed countries • However, >250 000 children died in Bangladesh in 2000 due to waterborne diseases
Table 3. Waterborne Pathogens Bacteria Viruses Protozoa Campylobacter Norwalk-like Cryptosporidium parvum Escherichia coli Entero (poliomyelitis,coxsackie, echo, rotavirus) Giarda lamblia Salmonella (nontyphoid) Hepatitis A Entamoeba histolytica Shigella Reovirus Yersinia Vibrio (noncholera) Salmonella (typhoid) Vibrio (cholera) Legionella
Etiologic Agents Most Frequently Identified in Waterborne Outbreaks of Infectious Diseases in USA 1971-1992 *Toxigenic E. coli, Yersinia, rotavirus, S. typhi, V. cholera and others
Outline • Why should we be concerned? • Outbreaks and pathogenes • Bacteria and viruses • Definition • Characteristics
Pore Size Silt Sand Gravel http://micro.magnet.fsu.edu/cells/index.html
Pore Fungi Bacteria Virus
Classification • Until 1800s, two classes of living organisms • Plants or animals (many people still have this perception) • In 1866, Ernst Haeckel proposed a third kingdom, Protista, which included all microorganisms, such as bacteria, protozoans, and certain fungi and algae.
Classification • Five-kingdom classification of living organisms • H.R. Whittaker of Cornell University (1969) • Alternative seven- and eight-kingdom classifications • Recently • Due to many factors (electron microscopy and gene sequencing, etc.) • Now, the five-kingdom system is commonly used
Bacteria • A fundamental biological distinction is made between bacteria and all other organisms. • genetic material (DNA and RNA) is NOT contained in a membrane-enclosed nucleus.
Nitrifying bacteria cross sectionPhoto credit: Mary Ann Bruns, Center for Microbial Ecology, Michigan State
Bacteria • Single-celled, with each cell carrying out all of the cell functions. • Bacteria have three basic shapes: • spherical, termed cocci (singular: coccus); • rod shaped, termed bacilli (singular:bacillus); and • spiral shaped. • Bacteria can group themselves in distinctive ways. For example, cocci that form grape-like clusters are termed staphylococci and those that form chains are called streptococci Streptococcus pyogenes
Waterborne Bacteria • Potential pathogens include Vibrio cholerae, Campylobacter jejuni, Salmonella species, and Escherichia coli (E. coli). • Why pathogenes? • secrete toxins that cause inflammation of the stomach and intestinal linings.
Color-enhanced scanning electron micrograph of Salmonella typhimurium (red) invading cultured human cells. Photo Source: Photo by Rocky Mountain Laboratories, NIAID, NIH with information from The National Institute of Allergy and Infectious Diseases
E-coli • Universally used in standard tests as indicators of fecal contamination. • E. coli strains vary widely in their pathogenicity. People tend to have a degree of immunity to local strains brought about by exposure (not visitors...! - tourista) • More dangerous strains: i.e., E. coli 0157:H7, can cause hemorrhagic colitis that results in thousands of life-threatening illnesses and hundreds of deaths a year. • (Although most are associated with food contamination, not contaminated drinking water)
E. coli O157:H7 http://www.microscopyconsulting.com/
Protozoans • Genetic material enclosed in a distinct membrane-covered nucleus. • Protozoans have a flexible outer covering, rather than a semi-rigid cell wall like bacteria.
Protozans • Play key roles in the environment: • decay of organic matter to constituting a large portion of plankton • Protozoans become dessicated easily and require damp or aquatic environments. • They are generally much larger than bacteria • some overlap between the largest bacteria and the smallest protozoans.
Protozoans – Important Feature • Capable of producing cysts under adverse conditions: • lack of moisture, food, or oxygen, or in the presence of toxic chemicals. • In the case of parasitic protozoans, the cyst allows the organism to survive outside a host (days to weeks), which is crucial for those protozoans whose life cycle requires multiple hosts. • Cysts present some challenges for water treatment because they are resistant to disinfection.
Protozoans and Cyst cycle giardia troph
Protozoa: Giardia • Giardia lamblia • possibly the most common cause of waterborne diarrheal disease in the north America • commonly endemic in day-care centers • more than 5% of adults and children are carriers who shed cysts in their feces, yet may have no symptoms. • Infection is usually through cyst-contaminated water.
Giardia Cyst in Stool Photo Source: www-medlib.med.utah.edu/parasitology/glambim.html
Protozoa: Cryptosporidium • Cryptosporidium • widespread in the natural environment • probably of greater concern than Giardia • because its smaller size makes it harder to filter • it is more resistant to disinfection.
Other Protozoae • Cyclospora and Microsporidia • recently emerging protozoal pathogens. • Cyclospora: • cysts are bigger than those of Cryptosporidium, must be mature before they are infectious. So, if cysts are shed from the body before maturation, the host can avoid infections. • Microsporidia: • less known and it is likely that cases may be underreported.
Viruses: Definition • Viruses fall into an entirely different category. • In fact, they may not qualify to be called organisms.
Viruses: Definition • All living organisms contain both DNA and RNA. Viruses may have DNA or RNA, but not both. • Unlike true living organisms, their nucleic acids are inactive outside of host cells. • once they enter host cells, their nucleic acids become active, and they are able to replicate.
Photo Caption: This is a slide of a type B viral Hepatitis as shown in its chronic stage.Photo Source: Transplant Pathology at the University of Pittsburgh,tpis.upmc.edu/
Viruses: Characteristics • Viruses in general are much smaller than bacteria. • can be viewed only by electron microcroscopes. • there is some overlap in size between the largest viruses and the smallest bacteria. • Their small size and resistance to environmental stress creates water treatment challenges. • viruses are less easily filtered by soil than bacteria, • viruses have been detected in groundwater that was absent of fecal indicator bacteria.
Viruses: Types • Enteric viruses that have been associated with waterborne disease outbreaks • Hepatitis A virus, Hepatitis E virus, Norwalk and Norwalk-type viruses, Rotaviruses, and Enteroviruses. ( large group that includes Polioviruses).
Viruses: Testing and Treatment • Difficult to test for the presence and concentration of viruses • Water systems that use surface water or groundwater that is directly under the influence of surface water are required to use a combination of treatment options and disinfection that will result in a four-log (99.99 percent) reduction or inactivation of viruses.
Outline • Why should we be concerned? • Outbreaks and pathogenes • Bacteria and viruses • Other waterborne • Algae and fungi
Fungi • have eucaryotic cells (genetic material in membrane-enclosed nucleus) • no chlorophyll • obtain nutrition by absorbing soluble substances across their cell walls • Fungi that are multi-cellular fall into the Fungi kindgom, which includes mushrooms and most molds.
Algae • The term “algae” has no officially recognized biological meaning. • Referred to any simple aquatic plant. Most biologists now use algae (singular: alga) to refer to organisms that have no true roots, stems, or leaves • Have chlorophyll and are capable of photosynthesis.
Mixed bloom of Dinophysis acuta and D. norvegica co-occurring with a bloom of Ceratium furca
Algae • Largely viewed mainly as the cause of taste, odor, and color problems • Some algae (cyanobacteria Microcystis, Cylindrospermopsis, and Anabaena) have recently come under more scrutiny in the U.S. for their health effects (linked to nerve and liver damage).
Algae • Algae and their toxins are currently unregulated by the Safe Drinking Water Act. However, they are included on EPA’s Drinking Water Candidate Contaminant List (CCL). • Australia has a regulatory program in place for cyanotoxins and the World Health Organization has a 1.0 microgram per liter guideline for microcystin.
Outline • Why should we be concerned? • Outbreaks and pathogenes • Bacteria and viruses • Other waterborne • Symptoms and illnesses
Illnesses Associated with Waterborne Pathogens • Bacteria and protozoa generally induce gastrointestinal disorders with a wide range of severity. Bacteria also cause life-threatening diseases such as typhoid and cholera. • Viruses cause serious diseases such as aseptic meningitis, encephalitis, poliomyelitis, hepatitis, myocarditis and diabetes.