Pests Pose Double Threat
In the spring, a young man's fancy turns to thoughts of love; a young tick's to thoughts of lunch. (Which, should he happen to be an outdoorsy type, could well be that young man.) Prodigious in wooded and grassy areas and in sandy soil near rivers, ticks carry several pathogens that can be transmitted to humans via their bite. The best-known is Borrelia burgdorferi, the microorganism that causes Lyme disease, which initially presents as flu-like symptoms and, left untreated, can cause persistent joint pain, cognitive deficits and, in rare cases, cardiac arrhythmia. But there are others. In 2010, the National Academy of Sciences Institute of Medicine called ticks "the Swiss Army knife of disease vectors."
In a study published in March in the journal Emerging Infectious Disease, Dan Salkeld, a disease ecology research associate at the Woods Institute for the Environment, encountered a newly identified human pathogen, Borrelia miyamotoi, along with B. burgdorferi, in nearly all the Bay Area recreation areas he and his collaborators examined. B. miyamotoi had previously been known to infect ticks, but it was only in 2013 that the first human cases in the United States were reported, and those were in New England. Given that little is known about the transmissibility of B. miyamotoi from ticks to humans and its health consequences, it's possible that other cases may have gone undiagnosed.
Stanford students taking the Conservation Medicine in Practice course taught by Salkeld and Woods senior fellow Eric Lambin in the spring of 2012 aided the research effort by collecting tick samples from the Jasper Ridge Biological Preserve and neighboring communities. Salkeld then expanded the study to include a total of 12 locations in Santa Cruz, Santa Clara, San Mateo, Marin, Mendocino and Contra Costa counties. Across all sites, 3.6 percent of the ticks were infected with Borrelia species, a relatively low prevalence compared with Northeastern states. Still, the Lyme-causing variant, B. burgdorferi, was detected at four sites, while B. miyamotoi was found at seven sites.
The surprising findings are "an important step toward dispelling the perception that you cannot acquire Lyme disease in California," says Ana Thompson, executive director of the Bay Area Lyme Foundation, which funded the research.
Fighting Food Allergies
An estimated 4 percent of adults in the United States suffer from a food allergy; for children under the age of 18 the rate is twice as high. Among those with food allergies, 30 percent react to multiple food groups, the most common being cow's milk, eggs, wheat, soy, peanuts, tree nuts, fish and shellfish. Reactions to the offending food(s) can range from mild, such as an itchy mouth or rash, to severe, including anaphylaxis and cardiac arrest.
While these risks can be minimized through constant vigilance—strict avoidance of the foods (even minuscule amounts can trigger a reaction) and carrying epinephrine at all times in case of accidental contact—there is no cure. But building on previous successes with a protocol known as oral immunotherapy, Stanford researchers led by Kari Nadeau are developing new tools for doctors that may help patients manage their food allergies more effectively.
Oral immunotherapy turns the notion of avoidance on its head. Under a doctor's supervision, patients ingest tiny amounts of the food or foods they are allergic to in powder form every day, gradually increasing the dose to build tolerance. (The process can take years for a single allergen.) The goal is to desensitize an allergy sufferer to the offending food(s) so that accidental contact won't provoke as severe a reaction. Once they are desensitized, patients must continue to consume a small amount of the food daily to maintain the protection.
In the latest pair of studies, published online in the journal Allergy, Asthma & Clinical Immunology in February, Nadeau, an associate in the division of immunology and allergy at the School of Medicine and Lucile Packard Children's Hospital, and Philippe Bégin, a research associate in her lab, established that simultaneous oral immunotherapy for multiple food allergens was feasible and safe. They also demonstrated that concurrent treatment with omalizumab, a drug approved for asthma, hastened desensitization. The combined therapy could reduce the duration of treatment and number of doctor's visits, potentially saving patients a substantial amount of money (even factoring in the cost of omalizumab).
However, the researchers emphasize that the studies were "proof of concept" and were not intended to examine the effectiveness of the regimen. Nadeau's team is currently recruiting subjects for a larger phase-2, randomized, controlled trial at Stanford and possibly other sites around the country.
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