It is now established that both the incidence and geographical range of Lyme disease is increasing. This tick-borne illness occurs in temperate regions of North America, Europe and Asia. If left untreated, it can cause a wide range of symptoms such as joint pain, severe headaches and neck stiffness, inflammation of the brain and spinal cord, Bell’s palsy and heart palpitations.
In North America, Lyme disease is predominantly caused by the bacterium Borrelia burgdorferi. Conversely, in Europe this disease is caused by five different bacterial species: B. burgdorferi, B. afzelii, B. garinii, B. spielmanii, and B. bavariensis.
The spread of Lyme disease is influenced by a variety of different ecological factors. For example, the rising incidence of Lyme disease in the northeastern US is thought to have been propelled by reforestation and recovery of deer populations occurring in the 20th century. In the present day, climate change is thought to be exerting a positive impact upon incidence of this disease by expanding the area of habitat suitable for ticks and other host species.
Lyme disease diagnosis
The bacteria that cause Lyme disease are transmitted from reservoir host species to humans via ticks, such as the black-legged tick (or deer tick), which act as vectors. Different reservoir host species can be more or less influential to the spread of Lyme disease, depending on the geographical region in question.
The white-footed mouse is a natural reservoir and extremely efficient transmitter of Lyme disease. Although bacteria such as B. burgdorferi cause Lyme disease in humans, studies suggest they have little to no effect on the tick burden or survival of these small mammals. In addition to mice, various other mammals are also capable of acting as hosts for Lyme disease including deer, shrews, chipmunks, squirrels and woodrats.
Much uncertainty remains regarding what specific underlying ecological factors are most important for the spread of Lyme disease. This lack of knowledge has made prevention and/or control of the disease difficult.
Furthermore, it is acknowledged that Lyme disease is an underreported condition that is harder to diagnose than many other infectious diseases.
One of the hallmark characteristics of Lyme disease is an erythema migrans or bull’s-eye rash. However, this rash does not develop in all patients. Furthermore, while in vitro diagnostic (IVD) devices do exist for the detection of Lyme disease, they are not currently used as a sole basis for diagnosis. This is due to concerns about false positive results and the fact that these tests are known to have low sensitivity in the early stages of the disease.
It is expected that the incidence of Lyme disease cases will continue to rise over the next decade. Public awareness of Lyme disease is also increasing and, with it, demand for accurate and efficient IVD devices.
There are currently 31 active pipeline products for Lyme disease at various stages of clinical development. Should any of these new products provide a clear benefit to patients, it is likely that they will be rapidly adopted.