Epidemiological and molecular investigation of resurgent cutaneous leishmaniasis in Sudan

Abstract

Objectives: Local health personnel have drawn attention to an apparent increase in incidence and severity of cutaneous leishmaniasis (CL) in Sudan. The objective of this study was to investigate CL burden and surveillance.

Methods: Surveillance data were compiled from the KalaCORE programme, Leishmania coordinators in Northern Kordofan and Southern Darfur, and Khartoum Dermatology Hospital. CL lesions were sampled from 14 suspected cases from Northern Kordofan and the Hospital for Tropical Diseases in Omdurman. PCR-restriction fragment length polymorphism analysis and multilocus sequencing were used to characterize the disease agent.

Results: All sites reported substantial increases from 2014 to 2016/7, far exceeding World Health Organization case reports for 2014, consistent with a widespread outbreak. Single seasonal peak incidence was observed, except for two peaks in Southern Darfur. In Northern Kordofan, the odds ratio for CL in the 35-44 years age group was 2.6 times higher than in the >45 years age group (p<0.0001); in Southern Darfur, the OR was 2.38 greater in males than females (p<0.0001). Lesions included severe presentations, despite chemotherapy. Leishmania major was identified as the agent.

Conclusions: Active surveillance is required to understand the extent of CL in Sudan, as well as training to standardize surveillance, diagnosis, reporting, and quality control. Point-of-care rapid diagnosis would be valuable. Genotyping and phenotyping are required to monitor the emergence of pathogenic strains, drug resistance, outbreaks, and changes in severity.

Keywords: Cutaneous leishmaniasis; Epidemiology; Leishmania major; Sudan.

Figure 1

KalaCORE data. (A) Geographical sources of data. (B) KalaCORE cutaneous leishmaniasis data for 2016 (blue bars), with temperature and rainfall data for 2015 overlaid, indicating a decrease in case reports with rising rainfall. (C) KalaCORE individual state data showing that Southern Darfur had additional peaks of case reports in May and October.

Figure 2

Southern Darfur and Northern Kordofan Ministry of Health data. (A) Southern Darfur Ministry of Health cutaneous leishmaniasis case reports showing differing profiles in 2016 (blue line) and 2017 (orange line). (B) Northern Kordofan cutaneous leishmaniasis cases reports by the Ministry of Health – Health Information System between 2010 and June 2016 (blue bars), and by hospital line listing from July 2016 to July 2017 (red bars), showing a sharp increase from 2015. (C) Northern Kordofan State cutaneous leishmaniasis case reports between July 2016 and July 2017, for which the month was reported, showing a peak in winter (February); 46 cases were excluded as the month was not reported. (D) Age distribution of cases, Southern Darfur (blue bars) and Northern Kordofan (orange bars).

Figure 3

Cutaneous leishmaniasis lesions. (A)–(C) Northern Kordofan State: (A) CL05, (B) CL06, (C) CL08. (D) and (E) Hospital for Tropical Diseases, Omdurman: (D) CL11, 3-year-old lesion, reported as Pentostam-resistant with multiple secondary infections, (E) CL12, a 2-year-old cutaneous lesion on the ankle of a sickle cell anaemia patient, also not responding to treatment. (F) Straw huts in a remote farming village near Barrah, North Kordofan State. Leishmania major was identified in samples from this location (CL05 and CL06).

Figure 4

PCR-RFLP identification of Leishmania species from cutaneous leishmaniasis lesions. (A) DNA extracted from ATL buffer, CL05 and CL06 produced the RFLP pattern characteristic of Leishmania major, with band sizes as described in the text. (B) DNA extracted from culture of the isolate from CL08 (MHOM/SD/2017/ELOBIED) also gave the pattern typical of L. major; PCR-RFLP of L. tropica was included as control. The L. major identification was verified by DNA sequencing (see text).