Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New approach assesses risk of water-borne pathogen disease

22.08.2006
Researchers at the University of California, San Diego (UCSD) School of Medicine, along with colleagues at the University Peruana Cayetano Heredia in Lima, Peru, have developed a novel approach for assessing the risk to humans of acquiring leptospirosis – a severe, water-borne disease that is the common cause of severe jaundice, renal failure and lung hemorrhage in urban areas throughout the developing world – from environmental water exposure.

The approach, which uses advanced molecular methods to measure risk for infection, may also be applicable to other water-borne bacterial diseases. The findings will be published on line August 21 in advance of the September issue of the journal Public Library of Science (PLoS) Medicine.

"What we found supported our hypothesis that severe leptospirosis in the Peruvian Amazon is associated with higher concentrations of more virulent forms of the bacteria at sites of exposure and transmission," said Joseph Vinetz, M.D., Associate Professor of Medicine in UCSD's Division of Infectious Diseases..

This approach to risk assessment of environmental surface waters is globally applicable, and can connect the presence of water-borne pathogens to the risk of mild versus severe human disease, according to the researchers. Scientists will be able to determine if a sample of water contains Leptospira, as well as quantify how many of the bacteria are present. More densely contaminated water sources would be more likely to cause human disease than water with a lower concentration of Leptospira.

"This can have direct policy implications for health departments in monitoring the safety of water for bathing, cleaning and swimming – all ways that diseases are spread, not just by drinking contaminated water," Vinetz said, adding that the next step is to intervene and clean up the water sources, and assess the impact of cleanup on the incidence rate of human leptospirosis.

The researchers successfully used a powerful molecular technology called polymerase chain reaction (PCR) to measure and compare levels of Leptospira in environmental surface waters at urban and rural sites in the Peruvian Amazon region of Iquitos. Leptospirosis, caused by bacteria of the genus Leptospira, is the most common disease in the world transmitted from animals to humans.

Annually, tens of millions of human cases of leptospirosis occur worldwide, and fatality rates can range as high as twenty to twenty-five percent in some regions. It occurs in both industrialized and developing countries, but is particularly prevalent in tropical countries where poor people live under highly crowded conditions, or in rural areas where people are exposed to water contaminated by the urine of Leptospira-infected mammals such as livestock or rats. Transmission also appears to coincide with warm weather and the occurrence of flooding, which washes soil contaminated with animal urine into water sources such as wells and streams.

Recent outbreaks worldwide among adventure athletes, military personnel and travelers highlight the risk for acquiring leptospirosis in tropical environments. Noted risk factors include the use of well or stream water, minding livestock, walking barefoot and the presence of rats and cats in the home.

Previous data from the Peruvian Amazon region indicated that the overall incidence of human leptospirosis was similar in urban and rural sites. However, the severe form of the disease had only been observed in urban areas. Vinetz and his research team tested two hypotheses: first, that concentration of more virulent Leptospira would be higher in urban than in rural environmental surface waters; and that the concentration and species of disease-causing Leptospira in the water would be associated with both the risk of acquiring the disease and its severity.

Standard lab culture-based methods of identifying Leptospira in water and soil sources are time-consuming, laborious, and usually unable to identify pathogenic Leptospira at all. To overcome these limitations, the scientists analyzed relatively small quantities of surface water – for instance water from gutters, wells, puddles and streams – using quantitative real-time PCR assays that amplify small amounts of DNA. By measuring DNA, the researchers were able to effectively describe and quantify the amount of pathogenic bacteria present in the water samples.

The scientists then were able to connect the molecular identification of the bacterial pathogens in the water samples to those actually infecting people and causing acute leptospirosis in rural and urban areas. This approach allowed for a precise mechanistic connection between source of infection and human disease, allowing the researchers to measure the environmental risk for bacterial infection – an approach never used before.

"This study is important because we have connected clinical and basic science to provide a quantitative risk assessment for water-borne diseases," said Vinetz. "This method of risk assessment for infection may also be applicable to other water-borne diseases such as those caused by Shigella, Salmonella, Cryptosporidium, and E. coli."

Debra Kain | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Diamond-like carbon is formed differently to what was believed -- machine learning enables development of new model

19.04.2018 | Materials Sciences

Electromagnetic wizardry: Wireless power transfer enhanced by backward signal

19.04.2018 | Physics and Astronomy

Ultrafast electron oscillation and dephasing monitored by attosecond light source

19.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>