New Antibiotic Ointment Prevents Lyme Disease from Tick Bites
A new antibiotic ointment that prevents Lyme disease in animal model studies may be available soon for human use as a topical cream applied directly to a tick bite.
Lyme disease is caused by an infection from the bite of a tick that is infected with the bacterial species Borrelia burgdorferi. Lyme disease is typically easily cured if treated soon after an infection. However, if the infection goes unnoticed and the disease is allowed to progress for a prolonged period, symptoms and treatments become increasingly problematical as the skin, joints, heart and nervous system become severely affected.
Ticks belong to the arachnid family and are related to chiggers, spiders and mites. The most common carrier of Lyme disease in North America is the deer tick. The life cycle of a deer tick follows four stages of development: egg, larva, nymph and adult. When an egg hatches, a 6-legged larval form emerges that appears as tiny as a speck of pepper. This 6-legged larval form is what people commonly refer to as a “seed tick.” After the larval form feeds off a host, it molts into a larger, 8-legged nymph form that lacks sexual differentiation. The nymph form then feeds off of a host and molts into its final adult form that is either male or female. It is the female that then requires a blood meal in order to lay eggs and complete the life cycle.
When bitten by a tick carrying Lyme disease, the most common sign is a red, circular “bulls-eye” rash followed by joint pain and muscle tenderness within a few days to several weeks following the bite. A diagnostic blood test for Lyme disease may show a false-negative due to antibodies from the immune system response may not manifest in the bloodstream until 4 to 6 weeks after a bite. When Lyme disease is suspected, prophylactic antibiotic therapy, either orally or intravenously, is given for several weeks. In 2009, there were approximately 30,000 confirmed cases of Lyme disease and more than 8,500 probable cases.
In 2009, 95% of Lyme disease cases were reported from 12 states:
However, the number of incidences and the treatment for a suspect tick bite may change in the near future. Researchers at the Fraunhofer Institute for Cell Therapy and Immunology in Leipzig, Germany reported recently in the Journal of Antimicrobial Chemotherapy their findings that topical treatment of the antibiotic azithromycin can prevent Lyme disease in animal model studies.
The researchers subjected experimental mice to the bacterial spirochaetal organism Borrelia burgdorferi via their skin in comparison studies through both tick-bites and needle injections. What they found was that in all cases, Lyme disease was prevented. Moreover, that the topical antibiotic azithromycin has protective effects if given even up to 3 days after exposure to the bacterium that causes Lyme disease.
The results are so promising that the efficacy of the researcher’s local antibiotic therapy for the treatment of Lymes disease from tick bites is now in progress in Phase III human clinical trials.
Source: “Evaluation of the preventive capacities of a topically applied azithromycin formulation against Lyme borreliosis in a murine model.” J. Antimicrob. Chemother. (2011) doi: 10.1093/jac/dkr371; Fraunhofer Institute for Cell Therapy and Immunology, Cell Technology/GLP, Perlick Strasse 1, 04103 Leipzig, Germany