Preliminary study on investigation of zoonotic visceral leishmaniasis in endemic foci of Ethiopia by detecting Leishmania infections in rodents

Wossenseged Lemma; Asrat Bizuneh; Habte Tekie; Habtamu Belay; Hirut Wondimu; Aysheshm Kassahun; Welelta Shiferaw; Meshesha Balkew; Ibrahim Abassi; Gad Baneth; Asrat Hailu

doi:10.1016/j.apjtm.2017.03.018

Preliminary study on investigation of zoonotic visceral leishmaniasis in endemic foci of Ethiopia by detecting Leishmania infections in rodents

Asian Pac J Trop Med. 2017 Apr;10(4):418-422. doi: 10.1016/j.apjtm.2017.03.018. Epub 2017 Apr 6.

Authors

Affiliations

¹ Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia. Electronic address: [email protected].
² Department of Microbiology, Immunology and Parasitology, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
³ Department of Zoological Sciences, College of Natural Science, Addis Ababa University, Addis Ababa, Ethiopia.
⁴ Department of Parasitology, Faculty of Science, Charles University in Prague, Vinicna 7, 12844, Prague 2, Czech Republic.
⁵ Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
⁶ Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Centre for the Study of Infectious and Tropical Diseases, The Hebrew University - Hadassah Medical School, Jerusalem, Israel.
⁷ School of Veterinary Medicine, Hebrew University, P.O. Box 12, Rehovot, 76100, Jerusalem, Israel.

PMID: 28552113
DOI: 10.1016/j.apjtm.2017.03.018

Abstract

Objective: To investigate the zoonotic visceral leishmaniasis (ZVL) by identification of the most probable reservoir hosts using parasite isolation and analysis of a possible transmission dynamics of the disease in extra-domestic agricultural fields and rural villages.

Methods: Rodents were collected from selected study sites in kala-azar endemic areas based on information for localities of kala-azar cases for screening of Leishmania infections using parasitological, serological and polymerase chain reaction (PCR) from March, 2013 to January, 2014. Ketamine (Clorketam Veterinary) was used to anaesthesize the rodents according the prescribed dosage (average 2 mg/kg for intra-venous route). The blood obtained using sterile needle was dropped into sterile filter paper and allowed to air dry before sealing in plastic bags. The tissues from liver, spleen and skin were macerated in Locke's solution before transferring them into NNN medium. Blood and touch smears of liver, spleen, skin and bone marrow were prepared for fixing using methanol and staining by Giemsa stain for microscopy. These tissues were also used for DNA extractions and PCR amplification of Leishmania infection.

Results: A total of 335 rodents (13 species) were analyzed by sampling internal organs. The infection rate by PCR was 11.1% (6/54) for Arvicanthis nilothicus compared to 17.6% (3/17) and 12.5% (2/16) for Acomys cahirinus and Tarera (G) robustus respectively. Almost all the infections were found from bone marrow samples (8/48 or 16.7%) compared with 1/91 (1.1%) liver, 2/87 (2.2%) spleen and 0/87 (0%) skin. In all study sites with past human VL cases, rodents and proved vectors shared similar habitats.

Conclusions: Leishmania donovani might circulate among different species of rodents in kala-azar endemic lowlands and valleys of Ethiopia by Phlebotomus orientalis and Phlebotomus martini. Detailed studies to substantiate the preliminary data on the possible role of these rodents are urgently needed.

Keywords: Ethiopia; Leishmania donovani; Phlebotomus martini; Phlebotomus orientalis; Reservoir hosts; Zoonotic visceral leishmaniasis.