Gerbillus nanus (Rodentia: Muridae): a new reservoir host of Leishmania major

Abstract

Gerbillus nanus Blanford, 1875 known as Baluchistan gerbil, is a granivorous solitary naked-footed species. No evidence of its natural infection with the protozoan parasite, Leishmania, has so far been provided. Cutaneous leishmaniasis (CL) is a major public health problem in many parts of the world, including Iran. The annual nationwide incidence of human CL due to Leishmania major (CLM) in endemic rural areas was above 18 000 cases in 2008. The detection of L. major in rodents is of fundamental importance for incriminating them as potential reservoirs of CLM infection. Between April 2007 and April 2008, following detection of 245 clinical cases in Jask region of south-east Iran, wild rodents were captured and checked by the microscopic slide smears for leishmanial infections. Overall, 106 gerbilline rodents were captured from which 17 were identified as Gerbillus nanus. Females of Meriones hurrianae, Tatera indica and G. nanus were found to be naturally infected with L. major. The presence of these parasites in G. nanus has never been reported before. All the amastigote-infected rodents came from the eastern plain of this region, except one T. indica from the western plain which was found to be smear-positive or kinetoplast DNA-positive by PCR. The highest (11·8%) prevalence of infection among rodents confirmed by PCR to be infected with L. major was attributed to Baluchistan gerbil, G. nanus, which is thus incriminated as a potential reservoir host of L. major in Iran.

The meticulous help provided by the anonymous referees is appreciated. The authors are grateful for the precious logistical support given (to carry out the field and laboratory work) by the Tropical and Infectious Diseases Research Centre, HUMS, Bandar Abbas, Iran. We appreciate help with laboratory work from Mr M. Kalantari, initial rodent identification by Ms M. Adnafi and expert verification of rodent identity by Dr Jamshid Darvish. Finally, the authors are also indebted to the Vice-chancellor for Research and Technology at SUMS for permitting the use of facilities at the university. This paper was the result of research plan (No. M/P/251 dated 1-1-2008) carried out under the auspices of HUMS.