New research published in the journal Zoonoses and Public Health reports on the presence of Lyme disease bacteria in Italy and the potential for human infection. Specifically, following a handful of cases of Lyme disease in Ossola Valley, an area of Piemonte in north-west Italy, the scientists took it upon themselves to assess the presence of Borrelia bacteria in ticks in the region.
After dragging for ticks in the mountainous region of Piemonte, during the summer months between April and September, Pintore and colleagues collected and analysed 1662 Ixodes ricinus ticks, known to be a vector for Lyme disease transmission. Lyme disease in Europe is typically caused by a different subspecies of Borrelia bacteria than causes Lyme disease in North America. Instead of Borrelia burgdorferi sensu stricto, European ticks frequently carry a range of Borrelial species.
These scientists examined the 1662 ticks collected after flagging, in addition to 104 ticks collected from 35 hunted wild animals, including 4 chamois, 8 roe deer, and 23 red deer. They ran polymerase chain reaction (PCR) tests on 327 of the flagged ticks and 25 of the ticks taken from the wild animals, looking specifically for the 16S rRNA gene of B. burgdorferi sensu lato (the overarching family to which B. burgdorferi s.s., B. afzelii, and others belong).
Lyme Disease Bacteria Vary in Italian Ticks
The results showed the presence in these ticks of B. afzelii (prevalent in 4% of the ticks), B. garinii (1.5%), B. lusitaniae (4%), and B. valaisiana (0.3%). The positive samples were sequenced after retesting using a PCR assay specific for the 5S-23S rRNA intergenic spacer region. These species of bacteria were found to be capable, in almost all cases, of causing infection in humans, resulting in symptoms of Lyme disease.
Symptoms of Lyme Disease in Europe
Due to the difference in bacteria causing Lyme disease in Europe, the sympomology of the disease is also different. Instead of Lyme arthritis, a typical feature of cases in the US, European Lyme disease symptoms may be more likely to involve the central nervous system, resulting in cognitive symptoms such as confusion.
In addition, it may be that a bite from a European tick will transmit the infection more quickly than a US tick bite as the Ixodes ricinus ticks have been found to carry bacteria in their saliva rather than in their gut.
This latest research in Italy confirms the presence of ticks carrying bacteria responsible for Lyme disease and will hopefully help inform public health policy as regards raising awareness of Lyme disease prevention and management in this region of Italy.
Pintore MD1, Ceballos L, Iulini B, Tomassone L, Pautasso A, Corbellini D, Rizzo F, Mandola ML, Bardelli M, Peletto S, Acutis PL, Mannelli A, Casalone C. Detection of Invasive Borrelia burgdorferi Strains in North-Eastern Piedmont, Italy. Zoonoses Public Health. 2014 Sep 15. doi: 10.1111/zph.12156. [Epub ahead of print]