How Common is Lyme Disease Globally and in Urban Settings?

Discussion Lyme disease (LD) is caused by several genospecies of Borrelia burgdorferi senu lato that are transmitted by ticks of the Ixodes ricinus complex. In the U.S. and Europe it is the most common vector-borne disease. It is named for Lyme, Connecticut in the 1970s when it was “discovered,” but there are reports of LD-type disease in Europe since 1883. There are 18 distinct genospecies with B. afzelii, B. garinii and B. burgdorferi sensu stricto being the 3 most common ones causing human infection. There are many species of Ixodes ticks but only 4 commonly bite humans. Ixodes ricinus mainly in Europe, I, persultcatus in Asia, I. scapularis in the eastern and central US, and I. pacificus in the western US and Canada. However I. pacificus is rarely infected and accounts for very few human infections. I. scapularis lives for approximately 2 years and eats blood meals at each of its 3 stages, larval, nymph and adult. Ticks are not infected when they hatch from eggs (a single female can produce > 2000 larvae). They become infected from the blood they feed upon. For I. scapularis, reservoir hosts for larva and nymphs are small mammals (i.e. mice, shrews) and birds. Adults like larger mammals such as deer and dogs. (Dogs are used as sentinels for epidemiological studies of Borrelis sp. in the environment). Humans are dead-end hosts as the spirochetes are not sustainable in human tissues in large numbers. I. scapularis ticks need attachment to transmit LD (usuall...
Source: PediatricEducation.org - Category: Pediatrics Authors: Tags: Uncategorized Source Type: news