Antibodies to Congo-Crimean haemorrhagic fever, Dhori, Thogoto and Bhanja viruses in southern Portugal.

Dhori and Thogoto viruses have been isolated from ticks in Portugal. In this country favourable ecologic conditions exist for other tick-borne viruses such as Bhanja and Congo-Crimean haemorrhagic fever (C-CHF) viruses. A serological survey for antibodies to these 4 tick-borne viruses in 258 human and 141 goat sera was done using the plaque reduction neutralization (PRN) and indirect fluorescent antibody (IFA) tests. Six human sera were found with antibodies to Dhori (2), Thogoto (2) and C-CHF (2) viruses, while seven goat sera had neutralizing antibodies (NA) to Dhori (5) or Bhanja (2) virus. From these results it seems likely that Bhanja and C-CHF, not yet isolated in Portugal, may exist focally in certain areas of southern Portugal.