• UCSBgauchos twitter avatar
    What a way to start off the season! @UCSBMensSoccer tops No.5 Stanford 1-0 Friday. RECAP >>> http://t.co/gPhjHwqFP0 http://t.co/z7Z90RLG5D
    17 hours 13 min ago
  • UCSBgauchos twitter avatar
    The Gauchos start the 2015 season off in style, hold No. 8 Stanford scoreless to win 1-0. @UCSBMensSoccer first win over Stanford since 2004
    18 hours 22 min ago
  • UCSBgauchos twitter avatar
    Stanford trying desperately to get on the board but UCSB's backline can't be beat. Gauchos lead 1-0 with 5 minutes to go
    18 hours 29 min ago
  • UCSBgauchos twitter avatar
    Ahinga Selemani beats his defender to set up Geoffrey Acheampong beautifully in the box, but the lefty's shot goes wide of the post
    18 hours 56 min ago
  • UCSBgauchos twitter avatar
    Stanford with a pair of good chances with just under 30 minutes to go but UCSB still finds a way to keep them off the board and lead 1-0
    19 hours 1 min ago
  • UCSBgauchos twitter avatar
    .@UCSBMensSoccer leading No. 8 Stanford 1-0 at the half thanks to a goal by who else, Nick DePuy. Great first half for the Gauchos
    19 hours 29 min ago
  • UCSBgauchos twitter avatar
    GOAL! Seo-In Kim sends a cross far post and Nick DePuy heads it in to put the Gauchos up 1-0 with 3 minutes left in the half
    19 hours 37 min ago
  • UCSBgauchos twitter avatar
    Women's Soccer: San Jose State 1, UC Santa Barbara 1 (Final - 2OT) UCSB, San Jose State Battle to 1-1 Tie http://t.co/KolrGPE4AY
    19 hours 50 min ago
  • UCSBgauchos twitter avatar
    Big save by Vom Steeg to keep the game scoreless! 25 min left in 1st half @UCSBMensSoccer
    20 hours 2 min ago
  • UCSBgauchos twitter avatar
    Stanford has the advantage in the run of play through 10 minutes but it's still 0-0. @UCSBMensSoccer
    20 hours 10 min ago
  • UCSBgauchos twitter avatar
    WVB: UCSB Opens Season with Back-to-Back Sweeps! #GoGauchos http://t.co/yye1PtugDW
    20 hours 38 min ago
  • UCSBgauchos twitter avatar
    Heres UCSB's starting lineup against Stanford: Vom Steeg, Quezada, Strong, Backus, Jome, Espana, Feucht, Murphy, Acheampong, Selemani, DePuy
    20 hours 38 min ago
  • UCSBgauchos twitter avatar
    Don't miss @UCSBMensSoccer season opener against Stanford. Kickoff in 10 minutes!
    20 hours 46 min ago
  • UCSBgauchos twitter avatar
    @UCSBWomenSoccer ties San Jose St. 1-1 in home season opener behind early goal by Mallory Hromatko
    20 hours 56 min ago
  • UCSBgauchos twitter avatar
    RT @UCSB_Volleyball: Make that two sweeps on opening day! We topped UIW 3-0 and are now 2-0!… https://t.co/iybbM7N1tn
    21 hours 30 min ago

Diseases of Another Kind

In a new paper, UCSB researchers scrutinize a distinctive and prevalent type of infectious agent
Wednesday, July 23, 2014 - 09:30
Santa Barbara, CA

Legionella pneumophila.jpg

Legionella pneumophila

Legionella pneumophila, the bacteria responsible for Legionnaires' disease.

 

Photo Credit: 

iStock

armand_and_kevin_ENH.jpg

Armand Kuris and Kevin Lafferty

Armand Kuris and Kevin Lafferty

Photo Credit: 

Sonia Fernandez

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.

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.”

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