Reaching those at risk: Active case detection of leprosy and contact tracing at Kokosa, a hot spot district in Ethiopia

Abstract

Introduction: Leprosy is a chronic mycobacterial disease of public health importance. It is one of the leading causes of permanent physical disability. The prevalence of leprosy in Ethiopia has remained stagnant over the last decades. The aim of the study was to identify new leprosy cases and trace household contacts at risk of developing leprosy by active case detection. The study area was Kokosa district, West Arsi zone, Oromia region, Ethiopia.

Method: A prospective longitudinal study was conducted from June 2016-September 2018 at Kokosa district. Ethical approvals were obtained from all relevant institutions. Health extension workers screened households by house-to-house visits. Blood samples were collected and the level of anti-PGL-I IgM measured at two-time points.

Results: More than 183,000 people living in Kokosa district were screened. Dermatologists and clinical nurses with special training on leprosy confirmed the new cases, and their household contacts were included in the study. Of the 91 new cases diagnosed and started treatment, 71 were recruited into our study. Sixty-two percent were males and 80.3% were multibacillary cases. A family history of leprosy was found in 29.6% of the patients with cohabitation ranging from 10 to 30 years. Eight new leprosy cases were diagnosed among the 308 household contacts and put on multi-drug therapy. The New Case Detection Rate increased from 28.3/100,000 to 48.3/100,000 between 2015/2016 and 2016/2017. Seventy one percent of leprosy patients and 81% of the household contacts' level of anti-PGL-I IgM decreased after treatment. In conclusion,the results of the study showed the importance of active case detection and household contact tracing. It enhances early case finding, and promotes early treatment, thereby interrupting transmission and preventing potential disability from leprosy.

Fig 1. Flow diagram of study participant’s recruitment at Kokosa District.

Fig 2. Age and sex distribution of patients affected by leprosy in Kokosa District.

X-axis represents age group and Y-axis represents frequency.

Fig 3. Leprosy patients enrolled in Kokosa ACD study.

A and B = MB patients.>5 cutaneous lesions; C = PNL, no cutaneous lesions; D = MB (LL) with numerous nodules; E = PB with< 5 cutaneous lesions [(Photos by Tsehaynesh Lema (PI)].

Fig 4. Clinical characteristics of patients at enrolment.

G0D = grade 0 disabilities, G1D: Grade 1 disabilities, G2D: Grade 2 disabilities, ***9.9% of the patients are PNL cases without cutaneous manifestations.

Fig 5. Leprosy patients diagnosed with G2D in Kokosa ACD study [(Photos by Tsehaynesh Lema (PI)].

Fig 6. Level of biomarkers before and after treatment.

a) The levels of anti-PGL-I IgM in the plasma of leprosy patients before and after MDT. b) The levels of anti-PGL-I IgM among HHCs at enrollment and after a year (after the index patients completed MDT, 12 months for MB and 6 months for PB).