Biotech April 2006 Water Newsletter

Text Box: Legionella Incidence Rates The percentage isolation rates for water samples positive for Legionella during 2003 to 2006 are shown in the graph below. The average isolation rate for the previous 2005 was 10.8% (compared to 8.8% for 2004). Of the positive samples in 2005, 6.7% had a Legionella count in excess of 1,000 CFU/mL, 54.9% had a count in the range 100 to less than 1,000 CFU/mL and 38.5% had a count below 100 CFU/mL. 93.3% of isolates were Legionella pneumophila.

Biological Testing Reg No. 2787

Cert No. 7176 – 10

Editor: Glen Pinna

Text Box: Recent Legionella Outbreaks (Source: http://members.dodo.net.au/~jamgreen/legionnaires_disease_outbreaks_2006.htm) Sydney, Australia. March 2006. Two women were diagnosed with Legionnaires’ Disease and are recuperating in Royal North Shore Hospital. The only common link between the women is that they shopped at a Chatswood shopping centre. The NSW Health Department are reviewing cooling towers in the area. Orduña. Spain. March 2006.
The Basque Health department has closed a Hotel in Orduña following four people: three men and a woman, being diagnosed with Legionella. It is believed that the thermal baths were the source of the infections. Lakeside, USA. March 2006. Two residents of Otterbein North Shore Retirement Living Community have been diagnosed with possible cases of Legionnaires' disease, prompting Otterbein to relocate residents of its assisted-living unit. Officials said "four or five" other assisted-living residents who had shown some symptoms of the infection were tested but did not have Legionnaires'. All 35 people who live in the assisted-living unit at the facility just outside the Lakeside gates have been relocated to other parts of the campus, other health-care facilities, or to family members' homes. Melbourne, Australia. February 2006. Nine residents of Melbourne’s northern suburbs have been diagnosed with Legionnaires Disease. One man has died. The Health Department is yet to pinpoint the source of the outbreak. Legionellosis in Australia (Source: http://www9.health.gov.au/cda/source/cda-index.cfm) Following are the figures of legionellosis cases in Australia during 2005. The number of cases per State or Territory were: Victoria 56, Western Australia 71, South Australia 58, New South Wales 88, Queensland 48, Northern Territory 3, Australian Capital Territory 0 and Tasmania had 3 cases.

April 2006

Issue No.

Text Box: There is an internet newsgroup for Legionella established at http://groups.yahoo.com/group/legionnaires_disease/ I would request that all experts in water treatment and concerned people go to this site, join the group and visit it to ask and answer questions posted by others.

Text Box: Biotech Laboratories Pty Ltd Level 2, Administration Building, Greenslopes Private Hospital, Newdegate Street, Greenslopes Qld 4120 PO Box 505 Indooroopilly Qld 4068 Ph: (07) 3847 9488 Facsimile: (07) 3847 9890 E-mail: general@biotechlab.com.au Web site: http://www.biotechlab.com.au/

A variety of micro-organisms that can cause illness have been found in water. These can be introduced into the body by drinking and inhalation, or by exposure to skin or mucous membrane. They include bacteria, protozoa, algae and viruses. This discussion will cover the description, significance, water treatment required for elimination and health significance where applicable.

Vibrio

Vibrio cholerae and other pathogenic Vibrio species should be absent from drinking water. Vibrio species may be water-borne and there is some evidence to suggest that Vibrio cholerae may occur naturally in some surface waters. Cholera outbreaks have occurred from drinking water contaminated with Vibrio cholerae 01. Outbreaks can also occur from food contamination and person-to-person spread in areas of extreme overcrowding and poor hygiene.

Vibrio species have been isolated from a number of surface waters in Queensland, but not from reticulated waters. Although there has been no associations between isolations of these bacteria from source water and community infections.

Standard treatment of reticulated water is effective against Vibrio cholerae 01provided the water turbidity is low. It is recommended that if water from a river, creek, dam, spring or bore must be used, then boiling the water for 5 minutes is recommended.

Vibrio species occur naturally in brackish and saline waters but only a few species are capable of surviving in fresh water ecosystems. Most species, including the pathogenic species, are not, normally, able to grow except under highly eutrophic conditions. Vibrio species have been reported in tropical waters where the temperature remains reasonably constant at about 25 °C.

Symptoms of cholera may vary from a mild, watery diarrhoea to an acute diarrhoea, with characteristic rice water stools. Onset of the illness is generally sudden, with incubation periods varying from 6 hours to 5 days. Abdominal cramps, nausea, vomiting, dehydration, and shock; after severe fluid and electrolyte loss, death may occur. Illness is caused by the ingestion of viable bacteria, which attach to the small intestine and produce cholera toxin. The production of cholera toxin by the attached bacteria results in the watery diarrhoea associated with this illness.

Infective dose -- Human volunteer feeding studies utilizing healthy individuals have demonstrated that approximately one million organisms must be ingested to cause illness. Antacid consumption markedly lowers the infective dose.

Specific testing for Vibrio species in drinking water is not routinely required. The presence of Vibrio cholerae 01 from water used for drinking is of major health significance. However, other serogroups of Vibrio cholerae are part of the normal flora of some waters. Faecal coliforms, E. coli and to a lesser extent, coliforms, is regarded as a useful tool in determining the possible presence of Vibrio species in a water supply.

The next BioTalk will deal with Yersinia species.

Source: Australian Drinking Water Guidelines - 6: 1996. National Health and Medical Research Council of Australia & Agriculture and Resource Management Council of Australia and New Zealand. Foodborne Microorganisms of Public Health Significance. 5th Edition. 1997. AIFST (NSW Branch Food Microbiology Group. And US. FDA Foodborne Pathogenic Microorganisms and Natural Toxins Handbook.