Borrelia burgdorferi

Hi everyone, and welcome to this short recording where we will be considering Borrelia burgdorferi, the clinical condition that this organism is associated with and the virulence factors that it produces to ensure that it is a successful pathogen.

Now, we need to think about the clinical condition that Borrelia burgdorferi causes and this is Lyme disease. Now, we haven't known about Lyme disease for a long time. It was first identified in 1977, in Lyme, in Connecticut and there were a cluster of cases of patients suffering from symptoms that resembled juvenile rheumatoid arthritis. Five years later, Burgdorfer discovered the causative organism and that's why the organism is called Borrelia burgdorferi because it's named after the individual that discovered it. Now, if we think about Lyme disease actually, in the UK, in certain areas, particularly in Hampshire, we are a hotspot for Lyme disease. One of the reasons for this is because it's spread by a tick, the Ixodes tick. It's associated with deer. Now, if we think about a Borrelia burgdorferi infected tick, what will happen is the tick will bite the skin. If the tick is infected with Borrelia burgdorferi, the bacteria will enter the skin as the tick bites the individual, it will also inject virulence factors that will disrupt the immune response. Bacteria will multiply and migrate to the dermis. So, remember the epidermis is the top layer of the skin and the dermis is the deeper layer of the skin. Now, because the virulence factors have also been injected into the skin, these will disrupt the immune response, so we will have no immune response. There will be no neutrophils present, no eradication of the organism, and then the organism is able to spread to other areas of the body. Now, if the patient does not receive treatment, Borrelia burgdorferi can cause problems in the joints, the central nervous system, and other skin sites. So, when we think about Lyme disease, this is what we call an enzootic cycle. It's associated with a tick. Obviously, it will cycle between the tick, which is the vector and us, as the host. It's very much associated with mice and deer because we often find ticks on these animals and also natural areas as well. So, a good example in the UK within Hampshire is the new forest because patients can come into contact with ticks and actually can then end up putting themselves at risk of Lyme disease.