Bacteria and dementia: a short historical overview
There are many known causes of dementia, with bacteria being one of them. Despite the historic and modern significance of bacterial influence in the research of dementia and memory loss, they are currently commonly ignored. Hundreds of years ago, there was only one known reason for dementia was known: syphilis, which is also caused by bacteria. In the progress of this disease, initally nerves become infected, and eventually infection reaches the brain and starts doing damage from the inside. The last stage of syphilis is dementia, also called neurosyphilis. Alois Alzherimer himself only wrote on dementia present in neurosyphilis, and it was only the head of psychiatry department where Alzheimer worked, Emil Kraepelin, who has introduced a new classification scheme and a disease entity called Alzheimer’s disease.
At the beginning of 20th century syphilis was so prevalent that up to one in four mental patients suffered from syphilitic dementia. Additionally, the disease used to reap a deadly harvest before the introduction of penicillin in 1943.
Lyme disease and dementia
In present times, the main bacterial danger contributing to dementia is Lyme disease, caused by the borrelia burgdorferi bacteria. Humans become infected through tick bites, while ticks become infected by feeding on the blood of diseased birds, which carry the disease to various parts of the world. Presently we know of 23 species of ticks which have the potential to carry Lyme disease or similar diseases (such as ones caused by the borrelia bissetti bacteria).
Dementia causes a decline in mental faculties and memory loss, which have a severe negative impact on everyday lives of the diseased, their interpersonal relations, or earning capability. Lyme disease-caused dementia contributes to the problem by causing long-and short-term memory problems which are not only frustrating, but it also increases the confusion in the afflicted and those surrounding them. Remembering what they did yesterday, while normally taking no longer than a few seconds, becomes an effort which requires full concentration – and is not always successful. Alongside with problems with remembering past events, there are difficulties in remembering the present ones. The diseased confess, that they feel as if their capability to learn new things has been blocked. For example, they find it simple to read a book, but understanding and storing the information becomes nearly impossible. Even reading multiple times may not prevent the acquired contents from simply disappearing.
Spread of Lyme disease
Lyme disease is the most common animal-borne disease in the northern hemisphere, and the problem is growing continuously. It does not only weaken the body, but also contributes to dementia, also called the Lyme dementia. The mechanisms of its development are not yet known. While Robert Bransfield, an American psychiatrist, does possess documented cases of neurological symptoms, there is not enough drive among the scientific community to analyze his findings. Ernie Murakami, retired physician, monitors the spread of Lyme disease in the world. Ticks carrying the disease are present in over 65 countries, making Lyme disease a pandemic. The frequency of reporting cases is varied: in Canada it is one person per million, but 13 cases in 10.000 in Slovenia. In the USA, the CDCs report an increase of 329 thousand infected per year. To make matters worse, only about 10% of the cases are ever reported, since doctors do not recognize Lyme disease correctly. An estimated number of yearly infection is higher than hepatitis C, HIV, colon cancer and breast cancer combined. Lyme disease constitutes about 90% of all reported cases of animal-borne diseases.
Preventing a pandemic
In order to stop a pandemic, a two-part strategy is necessary. First, to cure clinical effects of the disease. Second, to eliminate the root causes. The latter task, however, is highly difficult and poses a large challenge for the scientific community.
Harvard Medical School Center reports, that habitats suitable for ticks will quadruple by 2080. Currently, the main problem is deforestation and shifting of habitats of ticks and malaria-bearing mosquitoes, caused by climate change. The increase in number of cities located near forests, reforestation after abandonment of agriculture, and an increase in number of deer, mice, or squirrels (being some of the animals which carry ticks) all contribute to the growing danger.
This is why it is believed, that the number of cases of Lyme disease and malaria will keep increasing. Even if we consider the most conservative estimates of its spread: the whole USA, part of Canada, whole Europe, Near East and China – over a half of human population will be at risk for Lyme disease and the resulting dementia.
While dementia and memory problems caused by Lyme disease do exist, an upside, if one can call it that, is that they respond well to antibiotic treatments. Are we ready to solve this rising problem?