Incidence of Lyme disease in North America has risen rapidly in the last ten years, and research indicates that this trend will continue. According to one study, variables related to climate change could cause the number of Lyme disease cases to go up 20% by mid-century.
As the amount of people affected by Lyme disease grows, so does our need to gain a better understanding of this complicated condition. At this point, most of us know that Lyme disease is transmitted by ticks called Ixodes, deer, or black-legged ticks. These ticks are vectors of a corkscrew-shaped bacterium called Borrelia burgdorferi that causes Lyme disease.
While we have a pretty good grasp on the basics of Lyme disease transmission, health care professionals and the general public alike are still learning about the dangers of Lyme co-infections. Along with Borrelia burgdorferi, ticks can carry many other bacteria as well as viruses, protozoans, and fungi – all of which can be transmitted in one single bite. This means that a person who contracts Lyme disease after being bitten by a tick may also be infected with other illnesses called co-infections and not even know it.
Like Lyme disease itself, Lyme co-infections are easy to miss and difficult to treat. This is especially true since many physicians who have only a basic knowledge of Lyme disease don’t even know about the existence of these co-infections, let alone what signs and symptoms they should be looking for.
In the interest of furthering the public understanding of Lyme co-infections, let’s take a closer look at one of the more common ones: Bartonellosis.
What is Bartonellosis?
Bartonellosis is a Lyme co-infection caused by Bartonella bacteria. These bacteria are mainly found in the lining of blood vessels, and they can infect humans as well as some animals. Bartonella often infect humans through exposure to cats that harbor the bacteria, resulting in serious illnesses like cat-scratch disease and endocarditis. But strong circumstantial evidence indicates that ticks can also carry Bartonella, and the bacteria may be transmitted through the same bite that infects a person with Lyme disease. This transmission could lead to Bartonellosis.
It was only recently that scientists began to see the link between tick bites and Bartonella, since the bacteria had previously been thought of as being carried primarily by cats. However, a number of patients who weren’t exposed to cats but reported having been bitten by a tick have been co-infected with Lyme disease and Bartonella bacteria. And the Centers for Disease Control and Prevention (CDC) reported in 2016 that they had identified six strains of Bartonella in patients with tick bites who experienced chronic symptoms associated with Lyme disease.
What are the symptoms of Bartonellosis?
Some of the early symptoms of Bartonellosis resemble those of Lyme disease. These include fever, headache, changes in appetite, and fatigue. Like Lyme disease, Bartonellosis can also cause a rash, although it is said to look more like stretch marks caused by pregnancy than the “bullseye” rash typically associated with Lyme disease.
People infected with Bartonellosis may also experience neurological symptoms such as:
- Memory loss
- Blurred vision
- Loss of balance
- Numbness in arms and legs
- Unsteady gait (ataxia)
- Psychiatric manifestations
People experiencing these types of symptoms are often inclined to seek the advice of a neurologist, but neither these doctors nor the patients themselves are likely to make the connection to Bartonellosis. That’s one of the reasons why this Lyme co-infection is so frequently misdiagnosed.
How is Bartonellosis diagnosed and treated?
Even if a physician is aware of the possibility that a patient may be co-infected with Bartonellosis, it’s a very difficult condition to diagnose. Standard blood tests are reportedly insensitive to Bartonella bacteria, and false negatives can occur. Polymerase chain reaction (PCR) and tissue biopsy are other diagnostic options, but they’re not always effective, either. T-cell/ELISPOT testing is also a promising option for the near future, but for now, in the absence of laboratory confirmation of Bartonellosis, a clinical diagnosis is sometimes a physician’s best choice.
As with Lyme disease, Bartonellosis is typically treated with antibiotics. Although some experts believe that uncomplicated infection by Bartonella bacteria may resolve on its own, it is generally agreed that more serious cases of Bartonellosis warrant antibiotic therapy. Courses of doxycycline or fluoroquinolones are often used individually to treat Bartonellosis, but some doctors report needing use various combinations of antibiotics for effective treatment.
As we expand our understanding of how Lyme disease is transmitted, there is still much to be done in the study of Lyme co-infections. Knowing that co-infections like Bartonellosis can be transmitted through the same tick bite as Lyme disease is an important first step, and learning to recognize signs and symptoms can help us determine the best way to diagnose and treat these illnesses.