By Renata Trister DO
Bartonella are gram negative bacteria and are difficult to isolate in the laboratory. These bacteria can live inside cells and in various locations in the body, protected from the immune system and antibiotics.
Generally, three conditions caused by bartonella, cat scratch fever (Bartonella henselae), trench fever (Bartonella quintana), and Carrion’s disease (Bartonella bacilliformis), but research over the past 20 years has shown that bartonella is much more complex.
Bartonella species are widespread in all mammals. Bartonella is typically spread by biting insects (fleas, ticks, mosquitoes, sandflies, lice, chiggers, biting flies, scabies, mites, and even louse-eating spiders), but can also be transmitted by contaminated animal bites and scratches.
The most common bartonella is Bartonella henselae. It is the cause of cat scratch fever. Classically, a scratch from a cat carrying B. henselae develops a rash followed by symptoms including low grade fever, headache, sore throat, and conjunctivitis about 3 to 10 days after the scratch. Swollen lymph nodes are typical and takes weeks to months to subside. Symptoms are not generally debilitating and resolve without treatment in most cases.
When bartonellosis with B. henselae is caused by an insect bite (ticks, fleas, mosquitoes) the symptoms are complex and highly variable.
Bartonella quintana, another common species of bartonella, is the cause of trench fever. The name comes from the trenches of WWI where soldiers lived in desperate and debilitating conditions. B. quintana, spread by body lice, causes symptoms of severe fever, headache, muscle aches, leg and back pain, skin rashes, conjunctivitis, and rarely, heart failure. Today, B. quintana is common in homeless people; again, transmitted by body lice. About 10-20% of homeless populations (3.5 million people in the US) harbor chronic infection with B. quintana.
After entering the body (by whatever means), bartonella infects specialized white blood cells called CD 34+. These blood cells are precursors for cells that line blood vessels and other tissues (endothelial cells). The microbe enters the cell and creates a cyst around itself to gain protection. It also turns off the ability of the cell to self-destruct. Chemical messengers stimulated by bartonella cause additional CD 34+ cells to congregate. These messengers simultaneously suppress other parts of the immune response. CD 34+ travel throughout the body and replace damaged endothelial cells. Bartonella becomes established inside blood vessels and uses red blood cells as a nutrient source.
If the person’s immune system is healthy, the cells of the immune system quickly gain the upper hand, and microbe is dispatched within a couple of weeks. In patients with compromised immune systems and other infections, a chronic condition can develop.
Typical Symptoms of Chronic Infection
Skin rash at the site of initial infection, low-grade fever (100-102), and swollen lymph nodes (near the initial infection site) are hallmarks of initial infection. Lymph nodes can be filled with pus and drain in severe cases. Other common symptoms include severe fatigue, muscle pain, body aches, and eye infection (conjunctivitis). Liver and spleen enlargement can occur acutely and with chronic infection. Chronic infection can be associated with relapsing low-grade fever. Chronic eye problems include blurred vision, photophobia and eye irritation. Bartonella commonly infects bone marrow with resulting bone pain. Another symptom of bartonella is pain in the soles of feet upon waking in the morning. This is associated with trauma to blood vessels in the soles of the feet.
Anemia can occur from bartonella scavenging nutrients from red blood cells.
Small vessel disease can affect the brain and nervous system. Headaches and depression may be linked to chronic bartonella infection. Poor stress tolerance and anxiety are also reported.
Small vessel disease can affect function of the autonomic nervous system (sympathetic and parasympathetic systems) resulting in postural orthostatic tachycardia syndrome (POTS).
Chronic bartonella infection affects the entire vascular system. Infection of cells lining the heart (endocarditis) can cause chest pain, shortness of breath, palpitations, and in some cases, damage to heart valves. Respiratory symptoms can include unexplained cough.
Bartonella can affect the urogenital region causing irritable bladder, kidney disease, pelvic pain, and infertility. There is evidence that bartonella can be passed during pregnancy and between partners.
Severely immunocompromised individuals (mainly AIDS) can develop cranberry-like skin lesions from proliferation of infected blood vessels under the skin.
Symptoms are highly variable and often not severely debilitating. The spectrum of symptoms widely overlaps with other low virulence microbes. An average doctor would mark it off as simply aging and offer only prescriptions to control the symptoms, nothing more. For this reason this infection is often overlooked.
Diagnosis and treatment of Bartonella
Indirect fluorescence assay (IFA) tests for antibodies (IgG and IgM) to bartonella. IFA is not very sensitive because antibodies levels tend to be low. Also testing is species specific and generally only tests for the most common species of bartonella. Frye Laboratories (Scottsdale, Az) offers both IFA and standard PCA.
Standard PCR tests for bartonella DNA in the blood. Because concentrations of the microbe are very low with chronic infection, this test is unreliable.
Fluoroquinolones and doxycycline are sometimes successful in treating bartonellosis. However, some doctors report the need to use several antibiotics in combination.