Original article

Low infectiousness of a wildlife host of Leishmania infantum: the crab-eating fox is not important for transmission

O.  COURTENAY  a1 a2 c1, R. J.  QUINNELL  a1 a3, L. M.  GARCEZ  a4 and C.  DYE  a1 a5
a1 Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
a2 Ecology and Epidemiology Group, Department of Biological Sciences, University of Warwick, Coventry, UK
a3 School of Biology, University of Leeds, Leeds, UK
a4 Instituto Evandro Chagas, Belém, Pará, Brazil
a5 Communicable Diseases, World Health Organization, Geneva, Switzerland

Article author query
courtenay o   [PubMed][Google Scholar] 
quinnell r   [PubMed][Google Scholar] 
garcez l   [PubMed][Google Scholar] 
dye c   [PubMed][Google Scholar] 


The epidemiological role of the crab-eating fox Cerdocyon thous in the transmission of Leishmania infantum is assessed in a longitudinal study in Amazon Brazil. A total of 37 wild-caught foxes were immunologically and clinically monitored, and 26 foxes exposed to laboratory colonies of the sandfly vector Lutzomyia longipalpis, over a 15-month period. In total 78% (29/37) of foxes were seropositive for anti-Leishmania IgG on at least 1 occasion, and 38% (8/37) had infections confirmed by PCR and/or by culture. Point prevalences were 74% (serology), 15% (PCR), and 26% (culture). No signs of progressive disease were observed. None of the foxes were infectious to the 1469 sandflies dissected from 44 feeds. A conservative estimate of the possible contribution of foxes to transmission was 9% compared to 91% by sympatric domestic dogs. These results show that crab-eating fox populations do not maintain a transmission cycle independently of domestic dogs. The implication is that they are unlikely to introduce the parasite into Leishmania-free dog populations.

(Received April 30 2002)
(Revised June 26 2002)
(Accepted June 26 2002)

Key Words: Leishmania infantum; infectiousness; Cerdocyon thous; Brazil, fox.

c1 Corresponding author: Ecology and Epidemiology Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK. Tel: +44 24 7652 4550. Fax: +44 24 7652 4619. E-mail: