Via Nature News & Comment: The growing global battle against blood-sucking ticks. Excerpt:
On a balmy day in late June, Scott Williams waits for a white-footed mouse (Peromyscus leucopus) to fall asleep. Williams, a wildlife biologist with the Connecticut Agricultural Experiment Station in New Haven, has just transferred the animal from a trap to a plastic bag containing a cotton ball doused in anaesthetic.
As soon as the mouse's breathing slows to one breath per second, Williams will take it out, draw blood, weigh it, put an ear tag on it for identification and check the animal for ticks, saving any that are engorged with blood. He must work quickly. The mouse will wake up in about two minutes, and she might be grumpy.
Williams is testing whether vaccinating mice against Borrelia burgdorferi, the bacterium that causes Lyme disease in the United States, can reduce the proportion of ticks that are infected. Health officials are looking on with interest. Connecticut has one of the highest rates of human Lyme disease in the country, and June is peak time for transmission. Borrelia burgdorferi infects an estimated 329,000 people in the United States each year, according to the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.
And although most people who get prompt treatment recover quickly — Williams has had Lyme three times — up to one in five develops long-term and potentially life-threatening symptoms, including heart, vision or memory problems, or debilitating joint pain.
Williams's approach is one of several strategies being tested in an attempt to thwart the spread of tick-borne diseases. Some, like the mouse vaccine, interrupt the pathogen's ecological circuitry by targeting the wild animals that pass along and amplify the disease. Others, such as efforts to revive a human Lyme vaccine, aim to protect people from infection directly.
A more radical approach could hamper the ability of ticks to bite humans or animals, potentially protecting against dozens of illnesses spreading across the United States, Europe, Africa and Asia.
That the field needs creative solutions is clear. Many long-recommended interventions, such as pesticide application or controlling populations of deer, which are an important host for adult ticks, have had mixed success in scientific studies. Even the time-honoured protective strategies that most people use are not evidence-based.
“We tell people to wear repellents, to do tick checks and to shower if they've been in the field, but there's very little data to show that these things reduce human illness,” explains Ben Beard, chief of the CDC's bacterial-diseases branch in the division of vector-borne diseases.