Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Diseases of Another Kind

24.07.2014

In a new paper, UCSB researchers scrutinize a distinctive and prevalent type of infectious agent

The drought that has the entire country in its grip is affecting more than the color of people’s lawns. It may also be responsible for the proliferation of a heat-loving amoeba commonly found in warm freshwater bodies, such as lakes, rivers and hot springs, which the drought has made warmer than usual this year.

Legionella pneumophila

Legionella pneumophila, the bacteria responsible for Legionnaires' disease.

Photo Credit: iStock

A 9-year-old Kansas girl recently died of an infection caused by this parasite after swimming in several area lakes. The amoeba enters the body through the nose of an individual and travels to the brain. Nose plugs can lower the odds of this rare but fatal pathogen entering the body.

The amoeba, Naegleria fowleri, is classified as a sapronosis, an infectious disease caused by pathogenic microorganisms that inhabit aquatic ecosystems and/or soil rather than a living host. Scientists at UC Santa Barbara studying infectious disease transmission published their findings in the latest issue of the journal Trends in Parasitology.

 “Sapronoses do not follow the rules of infectious diseases that are transmitted from host to host,” said lead author Armand Kuris, a professor in UCSB’s Department of Ecology, Evolution and Marine Biology (EEMB). “They are categorically distinct from the way we think infectious diseases should operate. The paper tries to bring this group of diseases into sharp focus and get people to think more clearly about them.”

A well-known example of a sapronosis is Legionnaires’ disease, caused by the bacteria Legionella pneumophila, which can be transmitted by aerosolized water and/or contaminated soil. The bacteria can even live in windshield-wiper fluid. Legionnaires’ disease acquired its name in July 1976, when an outbreak of pneumonia occurred among people attending an American Legion convention at the Bellevue-Stratford Hotel in Philadelphia. Of the 182 reported cases, mostly men, 29 died.

A major group of emerging diseases, sapronotic pathogens can exist independently in an environmental reservoir like the cooling tower of the Philadelphia hotel’s air conditioning system. Some, like the cholera protozoa, rely on mosquitoes to find disease hosts for them. Zoonoses, by contrast, require a human host.

According to Kuris, diseases borne by a vector — a person, animal or microorganism that carries and transmits an infectious pathogen into another living organism — are more or less virulent depending on how efficiently they are transmitted. As a result, virulence evolves to a level where it is balanced with transmission in order to maximize the spread of the virus.  However, Kuris noted that there is no virulence trade-off for sapronotic disease agents. Transmission of a sapronosis pathogen is able to persist regardless of any changes in host abundance or transmission rates.

 To quantify the differences between sapronoses and conventional infectious diseases, the researchers developed a mathematical model using population growth rates. Of the 150 randomly selected human pathogens examined in this research, one-third turned out to be sapronotic — specifically 28.6 percent of the bacteria, 96.8 percent of the fungi and 12.5 percent of the protozoa.

“The fact that almost all of the fungi we looked at are sapronotic is a noteworthy generalization,” Kuris said.

“You can’t model a sapronosis like valley fever with classic models for infectious diseases,” said co-author Kevin Lafferty, adjunct faculty in EEMB and a marine ecologist with the Western Ecological Research Center of the U.S. Geological Survey. “To combat sapronoses, we need new theories and approaches. Our paper is a start in that direction.”

Julie Cohen | Eurek Alert!
Further information:
http://www.news.ucsb.edu/2014/014332/diseases-another-kind

More articles from Life Sciences:

nachricht MACC1 Gene Is an Independent Prognostic Biomarker for Survival in Klatskin Tumor Patients
31.08.2015 | Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft

nachricht Fish Oil-Diet Benefits May be Mediated by Gut Microbes
28.08.2015 | University of Gothenburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

Im Focus: Self-healing landscape: landslides after earthquake

In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.

These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...

Im Focus: FIC Proteins Send Bacteria Into Hibernation

Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.

For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Production research by Fraunhofer IAO honored with three awards at the ICPR 2015

31.08.2015 | Awards Funding

Single-Crystal Phosphors Suitable for Ultra-Bright, High-Power White Light Sources

31.08.2015 | Materials Sciences

Manchester Team Reveal New, Stable 2D Materials

31.08.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>