First molecular epidemiological study of cutaneous leishmaniasis in Libya

Abstract

Background: Cutaneous leishmaniasis (CL) is a major public health problem in Libya. The objective of this study was to investigate, for the first time, epidemiological features of CL outbreaks in Libya including molecular identification of parasites, the geographical distribution of cases and possible scenarios of parasite transmission.

Methodology/principal findings: We studied 450 patients that came from 49 areas distributed in 12 districts in north-west Libya. The patients' ages ranged from 9 months to 87 years (median age 25 years); 54% of the cases were males. Skin scrapings spotted on glass slides were collected for molecular identification of causative agent. The ribosomal internal transcribed spacer 1 (ITS1) was amplified and subsequently characterized by restriction fragment length polymorphism (RFLP) analysis. In total, 195 samples were successfully identified of which 148 (75.9%) were Leishmania major, and 47 (24.1%) Leishmania tropica. CL cases infected with L. major were found in all CL areas whereas L. tropica cases came mainly from Al Jabal Al Gharbi (46.4%), Misrata (17.8%) and Tarhuna districts (10.7%). A trend of seasonality was noticed for the infections with L. major which showed a clear peak between November and January, but was less pronounced for infections by L. tropica.

Conclusion: The first molecular study on CL in Libya revealed that the disease is caused by L. major and L. tropica and the epidemiological patterns in the different foci were the same as in other Mediterranean foci of CL.

Figure 1. Geographical distribution of CL in Libya.

The map of Libya showing the areas endemic for CL. •Districts. ▴Endemic areas.

Figure 2. Molecular identification of causative CL species.

Restriction fragment length polymorphism (RFLP) analysis of the amplified internal transcribed spacer 1 region (ITS1) digested with restriction enzyme HaeIII and analysed by electrophoresis on 2.5% agarose gels. Three reference strains were used for comparison; Lane 1 = L. major: MHOM/PS/01/ISL659, Lane 2 = L. tropica: MHOM/PS/02/63JnF21 and Lane 3 = L. infantum MHOM/TN/1980/IPT1. 1 kb = molecular size marker. All other lanes show digested PCR product from clinical materials; lanes 4–7 = L. tropica cases from Al Jabal Al Gharbi, Misrata and Tarhuna districts; lanes 8–11 = L.major cases from Tripoli, Sirt, Misrata, Al Murqub.

Figure 3. Seasonal distribution of CL in Libya.

A. Seasonal distribution of CL cases as reported by the Libyan National Centre for Infectious Diseases and Control (1995–2008). The highest peak was from November till February. B. Seasonal distribution of CL cases caused by L.major showing a peak from November till January and by L.tropica that peaked in February. These results are based on data collected form 1995 to 2008.