TY - JOUR JF - Acarologia T1 - Histological observations on Borrelia burgdorferi growth in naturally infected female Ixodes ricinus VL - 39 IS - 1 SP - 11 EP - 22 PY - 1998 SN - 0044-586X SN - 2107-7207 PB - Les Amis d'Acarologia AU - Zhu, Z. UR - https://www1.montpellier.inrae.fr/CBGP/acarologia/article.php?id=228 DA - 1998-06-15 KW - Borrelia burgdorferi KW - growth KW - spirochaetal transmission KW - Ixodes ricinus female KW - systemic infection KW - histology KW - silver stain KW - ultrastructure AB - Borrelia burgdorferi in naturally infected, flat, blood-feeding and replete females was visualized by direct immunofluorescence assay, silver stain and electron microscopy. In the majority of flat females, borreliae were detected in the midget only. During blood-feeding, midgut lumen infection was only present in females fed for 0.5 and 1 day on rabbits. All infected females fed for 2 days or more, including engorged ticks, contained bacteria within all tissues other than midgut lumen. These phenomena indicate that, if regurgitation can occur as a mode of B. burgdorferi transmission, it must probably takes place at the beginning of blood-feeding. The demonstration of numerous spirochaetes in the tissue of acini and ducts of salivary glands in all systemically infected blood-feeding females, provides further support for the salivary transmission of the bacterium. Although systemic borreliae could be found intracellularly within different tick tissues, they were predominantly situated in the extracellular site. Penetration of host cells by B. burgdorferi was often detected in the basal region of the hypodermis and midgut and ovarian epithelium. The results indicate that B. burgdorferi multiplies in various tick tissues during and after blood-feeding. ER -