Canada may see new tick-borne threat: Babesia
Last year, Canadian public health officials and legislators made great strides in recognizing the existence and threat within their country of Borrelia burgdorferi (Bb), the tick-borne organism which causes Lyme disease. Now, there’s evidence that Babesia, a parasite which infects red blood cells and is transmitted primarily through the bite of black-legged ticks, may have reached Canada, as well.
The topic of ‘chronic’ Lyme disease had been hotly debated among medical groups, with infectious disease specialists coming under fire during a 2014 Senate hearing when one participant suggested that the growing number of Lyme disease cases were, in fact, cases ofchronic fatigue. Nonetheless, in mid-December, the Canadian Senate unanimously passed Bill C-442, the Federal Framework on Lyme Disease Act.
Now, there’s evidence that Babesia, a parasite which infects red blood cells and is transmitted primarily through the bite of black-legged ticks, may have reached Canada, as well. The organism is believed to be carried by ticks also infected with Borrelia burgdorferi.
Researchers have identified the first known case of Babesia microti in Manitoba, a province of Canada. Authors from the University of Manitoba reported recently in the Canadian Journal of Infectious Diseases and Medical Microbiology that a “7-year-old boy with a complicated medical history that included asplenia, acquired an infection with Babesia microti in the summer of 2013 and had not travelled outside of Manitoba.”
The boy was successfully treated with six weeks of Atovaquone and Azithromycin.
The University of Manitoba entomologists point out that 88 cases of Babesia were reported in Canada’s neighboring states of Minnesota, Wisconsin, and North Dakota.
The University of Manitoba entomologists also highlighted the following evidence that Babesia has already reached Canada.
• Blacklegged-ticks infected with Babesia microti have been collected from six different localities in Manitoba as early as 2010.
• The prevalence of Babesia microti ticks ranged from 1.8% to as high as 10% in other locations.
• Babesia microti has also been detected in the tissues from field collected rodents at two sites.
• Infected ‘bird-borne’ ticks had been observed in Ontario.
Researchers from the Yale School of Pubic Health believe human Babesiosis is reaching new regions. They recently demonstrated that mice infected with Lyme disease and Babesia could enhance the geographic spread of the disease. According to Maria Diuk-Wasser, senior author of the Yale School of Public Health study, “The findings provide a possible answer as to why human babesiosis is only emerging in areas where Lyme disease is well established.”
“We found that B. burgdorferi and B. microti co-occur in ticks more frequently than expected, resulting in enhanced human exposure” — Maria Diuk-Wasser, senior author of Yale study.
Unfortunately, like many of the other tick-borne illnesses, Babesia can be difficult to diagnose. And, it cannot be effectively treated with antibiotics such as doxycycline, amoxicillin and azithromycin, which are used to treat Lyme disease, Ehrlichia and Anaplasmosis.
Typically, a co-infection of Babesia with Lyme disease can increase the severity and duration of illness. In YaleNews, Diuk-Wasser points out that multiple infections “can cause more severe symptoms and sometimes make diagnosis more difficult.”
Meanwhile, authors of a 2014 study, published in PLOS One, warn physicians to evaluate patients closely for both Lyme disease and Babesia. “Given that co-infection for these two pathogens can exacerbate symptoms and requires distinct treatment, medical practitioners should be aware of the tendency for B. microti and B. burgdorferi to co-occur when diagnosing and treating tick-borne illness.”
There are over 100 known species of Babesia, a parasite, but only a few warrant concern for humans. Most cases involve Babesia microti and Babesia duncani. The severity of Babesiosis infections can vary, but it can be life-threatening to patients with weakened immune systems and the elderly.
Some individuals can present with flu-like symptoms, which include irregular fevers, chills, sweats, lethargy, headaches, nausea, body aches and fatigue. The disease can cause a specific type of anemia, called hemolytic anemia, since the parasites infect and destroy red blood cells. There are individuals who are asymptomatic, as well.
In early cases, Babesia parasites can be seen inside red blood cells using a thick smear test, according to the CDC. But, only a third of patients with Babesiosis were diagnosed microscopically in a study in the Northeastern US by Krause and colleagues in 1997–2000. The remaining Babesia patients were diagnosed with PCR and IgM antibody testing.
Babesia in the 7-year-old child was effectively treated with a 6-week combination of Atovaquone and Azithromycin. A combination of Atovaquone and Azithromycin was much better tolerated than Clindamycin and Quinine in a trial by Krause et al. Metronidazole and Tinidazole are examples of treatment for Babesia that have been suggested for individuals who do not tolerate or cannot afford the combination of Atovaquone with Azithromycin. The ideal regimen has yet to be determined.
It’s important to point out that unlike Lyme disease, its been documented that Babesia can be transmitted person-to-person through blood transfusions, making the disease particularly concerning. According to a study published in the September, 2014 issue of Transfusion, “cases of transfusion-transmitted babesiosis have been increasingly recognized. To date, no Babesia test has been licensed for screening US blood donors.”
The risk of Babesia for the U.S. and Canada will be addressed during a Lyme Disease Fundamentals Course to be held in Banff, Alberta on February 6th and 7th, sponsored by the International Lyme and Associated Diseases Society (ILADS).