A total of 128 ticks of the genus
Amblyomma
were recovered from 5 marsupials (
Didelphis albiventris
) - with 4 recaptures - and 17 rodents (16
Bolomys lasiurus
and 1
Rattus norvegicus
) captured in an urban forest reserve in Campo Grande, State of Mato Grosso
do Sul, Brazil. Of the ticks collected, 95 (78.9%) were in larval form and
22 (21.1%) were nymphs; the only adult (0.8%) was identified as
A. cajennense
. Viewed under dark-field microscopy in the fourth month after seeding,
9 cultures prepared from spleens and livers of the rodents, blood of the
marsupials, and macerates of
Amblyomma
sp. nymphs revealed spiral-shaped, spirochete-like structures resembling
those of
Borrelia
sp. Some of them showed little motility, while others were non-motile. No
such structures could be found either in positive Giemsa-stained culture
smears or under electron microscopy. No PCR amplification of DNA from those
cultures could be obtained by employing
Leptospira
sp.,
B. burgdorferi
, and
Borrelia
sp. primers. These aspects suggest that the spirochete-like structures found
in this study do not fit into the genera Borrelia or Leptospira, requiring
instead to be isolated for proper identification.
