Presence of Borrelia spp. DNA in ticks, but absence of Borrelia spp. and of Leptospira spp. DNA in blood of fever patients in Madagascar

- Borrelia spp. DNA was detected in Amblyomma (A.) variegatum ticks and Rhipicephalus (R.) microplus ticks in Madagascar.
- DNA of a Borrelia (B.) theileri-related borreliae was detected in R. microplus for the first time in Madagascar.
- Only low amounts of Borrelia spp. DNA were detected in the assessed ticks, indicating low numbers of organisms and indicating an at the most limited risk of transmission to humans.
- Borrelia spp. DNA was absent in the blood of fever patients from the highlands in Madagascar.
- Leptospira (L.) spp. DNA was absent in the blood of fever patients from the highlands in Madagascar.

The occurrence of tick-borne relapsing fever and leptospirosis in humans in Madagascar remains unclear despite the presence of their potential vectors and reservoir hosts.We screened 255 Amblyomma variegatum ticks and 148 Rhipicephalus microplus ticks from Zebu cattle in Madagascar for Borrelia-specific DNA. Borrelia spp. DNA was detected in 21 Amblyomma variegatum ticks and 2 Rhipicephalus microplus ticks. One Borrelia found in one Rhipicephalus microplus showed close relationship to Borrelia theileri based on genetic distance and phylogenetic analyses on 16S rRNA and flaB sequences. The borreliae from Amblyomma variegatum could not be identified due to very low quantities of present DNA reflected by high cycle threshold values in real-time-PCR. It is uncertain whether these low numbers of Borrelia spp. are sufficient for transmission of infection from ticks to humans.In order to determine whether spirochaete infections are relevant in humans, blood samples of 1009 patients from the highlands of Madagascar with fever of unknown origin were screened for Borrelia spp. − and in addition for Leptospira spp. − by real-time PCR. No target DNA was detected, indicating a limited relevance of these pathogens for humans in the highlands of Madagascar.