An experiment suggests potential for greater spread of tick-borne illness as temperatures rise
Climate change could turn some dog ticks into suckers for humans instead of canines.At temperatures around 38° Celsius (100° Fahrenheit), some brown dog ticks were more attracted to people than to dogs, experiments show. The ticks can carry the pathogen that causes deadly Rocky Mountain spotted fever.
“We can expect more frequent and larger disease outbreaks of Rocky Mountain spotted fever when hot weather occurs, and when we get hot weather more often,” says Laura Backus, a researcher at the University of California, Davis School of Veterinary Medicine. Patients with Rocky Mountain spotted fever can die if they don’t receive antibiotic treatment within five days. Around 5 to 10 percent of people infected succumb to the disease.
Previous research in Europe had suggested that ticks are more aggressive toward people in hot weather. To find out whether brown dog ticks’ preference of host depends on temperature, Backus and her colleagues captured babies and adults of two genetically distinct groups, or lineages, of the species Rhipicephalus sanguineus. One lineage hailed from a hot region in Arizona, and was considered a tropical tick. The other lineage, from Oklahoma, tolerates colder weather and is considered temperate.
