Effect Measure

The mortgage crisis and disease

Like most public health scientists I am fascinated by the complicated relationship between the environment and disease. You build a military base somewhere and sexually transmitted diseases follow. You build a dam in Egypt and urinary schistosomiasis, a chronic debilitating disease that also predisposes to bladder cancer, entrenches itself in an area because infected workers are attracted from far away endemic areas. They work and often urinate in the water, seeding the shallows of rivers and lakes with schistosome eggs. When the eggs get into the snails, they germinate, the schistosome matures and eventually finds its way to humans by water contact.

In fact any vector borne disease can be affected by the environment in unexpected ways. Here I am including the social environment in the equation. Consider the current mortgage crisis in the US:

Foreclosures are increasing West Nile virus dangers because of stagnant swimming pools behind abandoned homes.

The foul pools are breeding grounds for mosquitoes, which can pass West Nile to humans and horses. The spike in mosquitoes comes earlier than the usual summertime appearance of the pest.

The Greater Los Angeles County Vector Control District got 288 service requests last month, nearly double the 145 in May 2007.
Agency spokeswoman Truc Dever says “all of the evidence is pointing to a very active West Nile season.” (AP)

West Nile fever is caused by a bird virus (sound familiar?). The birds are infected by mosquitoes who transfer the virus from bird to bird. The mosquitoes that bite birds are not usually the same as the ones that bite humans, but there are so-called bridge vectors, mosquitoes that bite both. Apparently it is these viruses the vector control folks are concerned about in the swimming pools. It remains to be seen if the pools and abandoned houses will have any significant effect on the transmission of West Nile disease. We still don’t understand the factors that make one season much worse than another for this disease. But it’s plausible.

West Nile infection has a broad spectrum of severity, from virtually asymptomatic to severe neurological infection with chronic disabilities or even a fatal outcome. So if the proposed effect of abandoned swimming pools is valid, it is reasonable to say that along with the other miseries of these foreclosures, we can add fatal disease to the toll.

Our world is interconnected in surprising and often hazardous ways.


  1. #1 wenchacha
    June 7, 2008

    Revere: We’ve had West Nile here in the WNY area for several years now. The news was frightening at first, then people realized that West Nile is not lurking in every dark corner to jump out and bite you. Still, we are notified if a number of crows are found dead in an area; it may be a result of active WN in the area.

    Will Public Health agencies in California launch any sort of program to reduce the disease? Draining pools would be a good way, obviously, or at least adding anti-mosquito dunks to standing bodies of water.

    It’s sort of funny, really. People who wish to retain property values in their neighborhoods might have incentive to maintain the abandoned homes down the street, just for the sake of dollars. Here, they have extra incentive to reduce illness that can happen to anyone, anywhere, regardless of whether you can meet your mortgage payments or not.

    Maybe it could provide a model for demonstrating the importance of the public in Public Health. Every man for himself doesn’t work too well in a situation like this. At least no anti-vax nutters can fuss about it.

  2. #2 revere
    June 7, 2008

    wenchacha: I think they are putting Gambusia (larvae eating minnows) in the pools.

  3. #3 Douglas
    June 8, 2008

    West Nile bike brigade
    City hires cyclists to spread anti-mosquito pellets

    Cecilia M. Vega, Chronicle Staff Writer

    Wednesday, August 17, 2005

    With images of giant mosquitoes emblazoned on their yellow vests, they looked more like crime-fighting superheroes than insect abaters.

    A fleet of bicyclists descended upon San Francisco on Tuesday, armed with bike helmets, rubber gloves and the mosquito equivalent of kryptonite — small pellets they dropped into mosquito havens around the city in an attempt to combat the spread of West Nile virus.

    “I’m not afraid,” said Jim Henning, who when he initially applied for the job thought it involved being a bike messenger for a pest-control company. “That’s what this stuff is for, to make us safer.”

    The effort came one day after San Francisco announced the city’s first human case of West Nile virus. On Tuesday, health officials said they might never know whether the victim, a middle-age man whose identity was not made public, had contracted the illness in the city or elsewhere.

    As cyclists zipped in and out of traffic depositing the potent pellets into curbside catch basins, targeting the standing-water spots where mosquitoes typically breed, health officials continued their message of public awareness.

    “It’s not as though you can walk down the street and catch it from another person,” said Eileen Shields, spokeswoman for the city’s Department of Public Health.

    The virus, which is transmitted to humans and animals through mosquito bites, was first detected in the United States in 1999 in New York.

    On Monday, Butte County health officials announced the death of an elderly man, California’s fifth West Nile-related fatality.

    Hoping to avoid such a casualty, San Francisco will spend about $130,000 on its most recent effort to stop the insects from multiplying. Between August and October, 13 cyclists will target the city’s 16,000 catch basins, those dank spots that sit at the bottom of storm drains and collect water and debris.

    “We need to prevent West Nile virus from spreading to the extent that it is possible,” said Jared Blumenfeld, director of the city’s Department of the Environment.

    Abiding by a city law that forbids departments from using toxic pesticides unless absolutely necessary, the pellets dropped in the catch basins are nontoxic and attack larvae by preventing mosquitoes from maturing, without affecting water quality.

    The pellets, a larvicide called Altosid, target only mosquitoes and will not disturb fish or other animals, health officials said. Cyclists will drop about 150 to 200 pellets a day and will distribute them multiple times to various catch basins throughout mosquito season, which runs through October.

    “Just the idea of having a helicopter going over Lake Merced spraying is antithetical to what residents would allow,” Blumenfeld said, referring to tactics regularly employed by other counties, including Sacramento.

    Being San Francisco, the mosquito abatement program is not only environmentally conscious, it’s high-tech, too.

    The catch basins are linked to Global Positioning System tracking devices that allow city officials to identify those spots that have already been treated or still need to be. The cyclists also carry satellite devices that allow them to make continual updates on the status of certain basins.

    As more human cases of West Nile virus arise around the state, counties are searching for ways to control the spread of virus-carrying mosquitoes.

    Contra Costa and Sacramento counties also use the nontoxic pellets, and many others, including San Mateo, distribute small mosquito-eating fish to residents who use them in places like backyard ponds.

  4. #4 wenchacha
    June 8, 2008

    Douglas, what an excellent program! The cost of mosquito abatement is negligible in comparison to the results.

    Thanks for posting this.

  5. #5 floormaster squeeze
    June 9, 2008

    The health affects of stress related to high mortgage debt and foreclosure are much greater than the threats of increased West Nile virus activity.

    I wanted to post related to this on your thoughtful DailyKos-inspired discussion of public health last week. There are many economic issues “upstream” to the public health interventions and policy choices that many people make. While I am sure many people here are aware of this and sensitive I am always surprised how little is said and done about income disparity/education in relation to public health.

    “As to the cause of our illness
    One glance at our rags would
    Tell you more. It is the same cause that wears out
    Our bodies and our clothes.”

    Bertolt Brecht