Autism spectrum disorder (ASD) is an umbrella term for neurological disorders in which some aspect of communication, forming relationships with others, or responding to environmental stimuli is impaired. Although the exact causes of ASD are unknown, several factors appear to play a role, including inherited genetic patterns, exposure to chemicals or heavy metals, and certain biological agents. Infections have been found to play an important role in the development of ASD, as various pathogens — viruses, bacteria, and fungi — have been detected in samples from many patients diagnosed with ASD. For example, the parasite Taenia solium is one of the causes of neurocysticercosis, whose common symptoms include epilepsy, headaches, dizziness, stroke, and neuropsychiatric disorders. This condition develops when cysts form in the brain as the infection spreads. Toxoplasmosis is caused by Toxoplasma gondii, a protozoan. It usually does not cause significant symptoms in adults. It is typically contracted by consuming undercooked food containing cysts, through contact with infected cat feces, or transplacentally — that is, from mother to child during pregnancy if the mother is infected. (1)

At first glance, autism spectrum disorder and Lyme disease may not seem similar, yet in young children several characteristic symptoms overlap. Among neurological symptoms, such overlaps include disorientation, brain fog, confusion, light sensitivity, muscle twitching, communication difficulties, and both physical and mental developmental delays. There are also psychological symptoms that may appear in both conditions, though these are more complex to recognize: anxiety, mood swings, and behavioral disturbances. Physical symptoms such as joint inflammation, rash, and muscle weakness are also seen in both Lyme disease and autism spectrum disorder, and even gastrointestinal symptoms do not provide a clear distinction between the two diagnoses: food allergies, bloating, constipation or diarrhea, and general lower abdominal pain. Of course, other illnesses may present with similar symptoms as well — for example, most gastrointestinal complaints are typical of autoimmune diseases, and in adults Lyme disease is often misdiagnosed as arthritis or fibromyalgia.

Lyme disease is the most common vector-borne illness, typically transmitted through the bite of ticks — specifically, in Europe, ticks of the Ixodes species. The incidence of Lyme borreliosis is steadily increasing, and several factors may contribute to this rise. One of these factors is the possibility of mother-to-fetus transmission. The first scientific evidence was described in 1985, when a vertically transmitted Lyme infection was confirmed in both a mother and her newborn. There is well-established scientific evidence that the spirochete bacterium causing Lyme disease, Borrelia, is capable of crossing the placenta from mother to fetus. The well-known TORCH acronym — used in textbooks describing congenital infectious diseases — has since been expanded to TORCHES-CLAP, where the letter “L” stands for Lyme disease. (T: Toxoplasma, R: Rubella, C: Cytomegalovirus, H: Herpes simplex, E: Enterovirus, S: Syphilis, C: Chickenpox, L: Lyme, A: AIDS, P: Parvovirus B19.) (8)

One still unclear but plausible explanation for the development of autism spectrum disorder is vertical transmission — that is, fetal infection during pregnancy. Bransfield and colleagues proposed this theory and identified 24 infections and co-infections that may contribute to the early childhood onset of autism spectrum disorder. If this is the case, several unanswered questions arise: Is the primary form of infection acquired in infancy or during pregnancy? Is the underlying cause of the disorder the direct infection of neural tissue, or a secondary immune reaction to an infection — or possibly both?

An American study drew attention to a possible connection between Lyme disease / tick-borne illnesses and certain childhood neuropsychiatric disorders. Among the states with the highest rates of autism, 15 reported more Lyme disease cases than the national average. Conversely, among the states with the lowest autism rates, not a single one reported above-average Lyme disease incidence. This suggests a form of correlation between the occurrence of the two conditions. (2)

Although clinicians have previously suggested the possibility of a link between Lyme disease and autism spectrum disorder, the first research in this field provided a comprehensive picture of the medical history of 102 cases of Lyme disease during pregnancy. 9%of the subjects were diagnosed with autism, and most of them were found to have some kind of developmental disorder. As a control group, 66 mothers with Lyme disease who received antibiotics before and during pregnancy were studied: all of them gave birth to healthy newborns. In 25% of children who develop autism spectrum disorder, the causative agent of Lyme disease, Borrelia burgdorferi, can be detected. (3)

Tick-borne diseases — such as infection with Borrelia burgdorferi, the bacterium that causes Lyme disease — may facilitate the development of additional infections and create a weakened, vulnerable, and immunologically unprotected state during fetal and early infant development, which can favor the emergence of autism spectrum disorder. These disturbances can reinforce one another and, in the presence of other factors, may trigger immune reactions that, in susceptible individuals, lead to inflammation, molecular mimicry, alterations in the kynurenine metabolic pathway, elevated quinolinic acid levels, reduced serotonin levels, oxidative stress, mitochondrial dysfunction, and excitotoxicity. All of these impair the development of the amygdala and other neural structures and networks, potentially resulting in partial Klüver–Bucy syndrome, autism spectrum disorder, and other neuropsychiatric conditions.

This hypothesis is supported by numerous cases of pregnant women with Lyme disease and children diagnosed with autism spectrum disorder, as well as by fetal neurological abnormalities associated with tick-borne diseases. In addition, the similarities between tick-borne illnesses and autism spectrum disorder — including symptoms, pathophysiology, immune responses, temporal lobe pathology, and neuroimaging findings — are also noteworthy. (7)

In a study focusing on congenital Lyme disease, Charles Ray Jones and his colleagues observed that treating Lyme disease and other tick-borne infections during pregnancy may prevent the development of autism and other developmental disorders caused by these infections. (4)

A study of the effects of long-term antibiotic therapy conducted by Mason Kuhn et al. objectively demonstrated that antibiotic treatment reduces symptoms of autism spectrum disorder associated with Lyme disease/tick-borne disease. (5)

We also present data that have not yet been published in an official journal but were shown at a conference: a pediatrician specializing in autism — who is also a Lyme expert — shared his clinical observations. He administered combined antibiotic therapy to more than 100 children diagnosed with both autism and Lyme disease. In nearly 60 percent of the cases, the symptoms of autism (partly overlapping with Lyme disease) improved, while in 8 percent the symptoms worsened — the latter was resolved by adding an antifungal medication to the treatment.

Another “mysterious” childhood disease that has been linked to fetal Lyme disease is SMA, or spinal muscular atrophy. Recent studies also suggest a possible connection between ALS (amyotrophic lateral sclerosis) and SMA (spinal muscular atrophy). (6)

In a previous summary article published on Weborvos, the possible mother-to-fetus transmission of Lyme disease was described in detail, which—as it appears—may be closely related to the explanation of the connection between Lyme disease and autism spectrum disorder (8).

Further interesting video materials:

The case of a young boy diagnosed with autism, who also tested positive for Lyme disease, babesiosis, and mycoplasmosis: Youtube

A 2008 interview with Dr. Luc Montagnier — awarded the Nobel Prize in Physiology or Medicine for the discovery of the HIV virus — in which he discusses his research at the time on the potential link between autism and Lyme disease. (French audio with English subtitles.) Youtube

Sources:

1. M Zubair Alam, Q Alam, M Amjad Kamal, A Ahmad Jiman-Fatani, EI Azhar, M Azhar Khan…Infectious agents and neurodegenerative diseases: exploring the links .Current topics in medicinal chemistry, 2017 [PubMed]
2. Kuhn M, Grave S, Bransfield R, Harris S. Long term antibiotic therapy may be an effective treatment for children co-morbid with Lyme disease and Autism Spectrum Disorder. Med Hypotheses. (2012) 78:606–15. 10.1016/j.mehy.2012.01.037 [PubMed] [Google Scholar]
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6. Cetin B. A new complication of lyme disease; spinal muscular atrophy. Eur J Biomed Pharm Sci. (2019) 6:464–8.: MALSG
7. RC Bransfield, JS Wulfman, WT Harvey, AI Usman The association between tick-borne infections, Lyme borreliosis and autism spectrum disorders- Medical hypotheses, 2008 – Elsevier [PubMed]
8. The review article of Weborvos, based on several scientific publications Weborvos