Tick-borne diseases are a major public health problem around the world. Ticks carry and transmit a variety of microbes that cause disease. These illnesses, which include Lyme disease, Rocky Mountain spotted fever, and Tularemia, can cause a variety of symptoms, often serious and sometimes deadly.
Now, just in time for spring and the explosion of ticks in forests, lawns and trails, a new study by researchers from China and the University of Maryland School of Medicine (UM SOM) has uncovered a never-before-seen illness transmitted by ticks. It's possible that the disease could be a "substantial health threat" to humans and animals in areas where the carrier tick is common, the authors write in the paper.
J. Stephen Dumler, MD, a professor of pathology at the school, helped identify the newly discovered bacterial species, which the researchers named Anaplasma capra. The paper was published in the latest issue of the journal Lancet Infectious Disease.
"This is an entirely new species of bacteria," said Dr. Dumler, an expert on tick-borne diseases who has worked all over the world. "This had never been seen in humans before. We still have a lot to learn about this species, but it may be that this bacteria is infecting humans over a wide area." He collaborated on the paper with scientists at several Chinese institutions: the Beijing Institute of Microbiology and Epidemiology, the Mudanjiang Forestry Central Hospital, and the Shanghai Institute of Medical Genetics at Shanghai Jiaotong University. The lead author of the study was Wu-Chun Cao, MD, PhD, of the Beijing Institute.
The researchers tested 477 patients in northeastern China who had been bitten by a tick over a month-long period in the spring of 2014. Of those, 28, six percent, were found to have been infected by the new species of bacteria. This microbe is related to other Anaplasma bacteria, some of which can cause illness when transmitted from ticks to humans. Dr. Dumler himself discovered one such disease, human anaplasmosis, two decades ago.
The symptoms of A capra infection include fever, headache, and tiredness, dizziness and muscle aches. The researchers successfully treated the infection with antibiotics, particularly doxycycline.
Because no one knew the bacteria existed, no one has looked for it, and it is not clear how widespread it is. In China, the species appears to be common in goats - the researchers decided to call it "capra" because the word means "goat" in Latin. But it may also infect other animals. Currently, it is difficult to diagnose infection - there is no simple blood test.
The bacterium is probably transmitted via a tick species known as the taiga tick. This species, which is closely related to the deer tick, lives in Eastern Europe and across Russia and Asia, including China and Japan. If this tick species transmits A capra throughout this area, human infection may be common. Dumler notes that about a fifth of the world's population, more than a billion people, live in areas where the tick resides.
"Dr. Dumler continues to distinguish himself as an international leader in scientific discovery related to tick-borne illnesses," said Dean E. Albert Reece, MD, PhD, MBA, who is also the vice president for Medical Affairs, University of Maryland, and the John Z. and Akiko K. Bowers Distinguished Professor and Dean of the School of Medicine. "As we understand more about these diseases, we are able to better address this growing international public health problem, as we have begun to do with Dr. Dumler's previous discoveries."
About the University of Maryland School of Medicine
The University of Maryland School of Medicine was chartered in 1807 and is the first public medical school in the United States and continues today as an innovative leader in accelerating innovation and discovery in medicine. The School of Medicine is the founding school of the University of Maryland and is an integral part of the 11-campus University System of Maryland. Located on the University of Maryland's Baltimore campus, the School of Medicine works closely with the University of Maryland Medical Center and Medical System to provide a research-intensive, academic and clinically based education. With 43 academic departments, centers and institutes and a faculty of more than 3,000 physicians and research scientists plus more than $400 million in extramural funding, the School is regarded as one of the leading biomedical research institutions in the U.S. with top-tier faculty and programs in cancer, brain science, surgery and transplantation, trauma and emergency medicine, vaccine development and human genomics, among other centers of excellence. The School is not only concerned with the health of the citizens of Maryland and the nation, but also has a global presence, with research and treatment facilities in more than 35 countries around the world.
The Lancet Infectious Diseases