Travel Medicine and Infectious Disease
Eradicating leprosy in Saudi Arabia: Outcome of a ten-year surveillance (2003–2012)
Introduction
Leprosy is a public health problem because of its long incubation period, difficulties in its diagnosis, its transmission potential and its capacity to cause permanent disabilities with their social consequences of discrimination and stigma [1], [2], [3]. Worldwide prevalence of leprosy has fallen substantially in the past 50 years due to international, national and sub national campaigns, and the disease has been eliminated globally according to the WHO's definition [4], [5]. Introduction of MTD, improved early diagnosis and treatment, integration of primary leprosy services and effective collaborations and partnerships have led to a considerable reduction in leprosy burden. Nevertheless, new cases continue to occur in almost all endemic countries and high-burden pockets can exist against a low-burden background. Official figures from 115 countries show the global registered prevalence of leprosy at 189,018 at the end of 2012 and during the same year 232,857 new cases were reported. Of these 95% were from 16 countries (mainly in Asia, Africa, and South America) [6].Leprosy is a chronic granulomatous infection, principally affecting the skin and peripheral nerves, caused by the obligate intracellular organism Mycobacterium leprae [1], [2]. The damage to peripheral nerves results in sensory and motor impairment with characteristic deformities and disability [1]. Most people with leprosy are non-infectious as the mycobacterium remains intracellular. Patients with lepromatous leprosy, however, excrete M. leprae from their nasal mucosa and skin and are infectious [3]. The mode of transmission is still not conclusively proven, although person-to-person spread via nasal droplets is believed to be the main route [7].
Leprosy is more common among males than females. This is a well reported fact of leprosy epidemiology and is not thought to be related to under diagnosis in women, although in some countries it is accentuated by delayed presentation by female patients, which results in higher rates of deformity [2]. Generally, after the age of puberty, the male to female ratio of leprosy range between 1.5 and 2:1 [2]. However the proportion of females among new cases of leprosy can fluctuate by country. For example, in 2010, the proportion of females among new cases ranged from 57.5% in Liberia to 20.8% in Madagascar [6].
There are 2 systems used to classify leprosy patients. The Ridley-Jopling system [8] uses clinical and histopathological features and the bacteriological index. The different categories (tuberculoid leprosy, lepromatous leprosy and borderline leprosy) correlate with the activity of the host immune response. The WHO introduced a simplified classification system that uses the number of skin lesion to classify disease to simplify diagnosis, facilitate treatment, and decentralize leprosy services to primary health units as much as possible. This system uses the term paucibacillary (PB) when a person has up to five lesions, and multibacillary (MB) for more than 5 lesions [1].
Patients with MB leprosy are more infectious than those with PB leprosy: the risk of disease in contacts of cases with MB leprosy is twice as high as that in contacts of patients with PB leprosy [3]. In addition, patients with MB leprosy have a higher risk of developing reversal reactions and impairment of nerve function [9]. And if these patients relapse, they resume the ability to transmit the organism to others [3]. This WHO classification is widely used to guide treatment decisions.
The diagnosis of leprosy remains a clinical one and is complicated by the long incubation period and the unavailability of laboratory investigation methods. It can be difficult to diagnose leprosy especially in non-endemic regions or where the prevalence is very low. Late diagnosis leads to continued transmission and to increased risk of disability [10]. Factors associated with late diagnosis include delay by patients in presenting especially due to stigma and delay by health services in making a diagnosis [3]. Multidrug therapy (MDT), which is effective in eradicating M. leprae in most patients, was introduced in the early 1980s after the emergence of resistance to dapsone-only regimens [11]. In 1995, a resolution was passed to provide free MDT to all leprosy patients worldwide [3].
Treatment of leprosy in KSA is free for all Saudi patients. However, non-Saudi patients are treated for only one month and then deported to their countries of origin in accordance with the law in the Saudi Arabia. They are advised to continue treatment in their home countries while Saudi patients continue to receive treatments in their regions. Complicated cases of leprosy are referred to Ibn Sina hospital, the only reference hospital in Saudi Arabia for the treatment of leprosy. This hospital is located in the Makkah region where the country has the largest concentration of both legal and illegal immigrants.
The World Health Assembly passed a resolution in 1991 to “eliminate leprosy as a public health problem” by 2000; it defined elimination as reducing prevalence to less than 1 case per 10,000 population [4]. Elimination of leprosy globally was achieved in the year 2000 and the disease has been eliminated from 119 countries out of the 122 where it was considered as a public health problem in 1985 [5], [12]. However, leprosy was not eliminated from all countries and pockets of high endemicity in some areas of many countries still exist and transmission continues. A consensus has been reached by the WHO that close disease surveillance for leprosy is necessary, and a new target was introduced. The new target stressed that the number of new cases with grade 2 disability in 2015 should be 35% lower than in 2010 [13].
Leprosy is known to have existed in Saudi Arabia for a very long time and as part of the worldwide eradication program of the disease, the country has made leprosy one of the notifiable diseases since 1963 [14].
Previous reports on leprosy in Saudi Arabia showed incidence of the disease to be within the WHO's definition of 1 case per 10,000 population for countries classified as being in the phase of elimination [13], [15]. Nevertheless, new cases of leprosy are registered yearly in the country suggesting that Saudis continue to be infected. Therefore an improved epidemiological surveillance system for capturing all cases of leprosy in the country was established in 2003. This surveillance system was designed to also include zero-cases reporting and active case findings to assure close monitoring of the disease. Also as part of the public health interventions, the treatment of leprosy cases was integrated in the nationwide network of Primary Health Care Centers.
The objective of this paper is to give an epidemiological description of all cases of leprosy reported in KSA over a ten-year period and to estimate its yearly incidence. This will help identify any challenge to the successful elimination of leprosy in the Kingdom.
Section snippets
Method
This is a retrospective epidemiological study of all newly registered cases of leprosy captured in the country's surveillance system over a 10-year period from 2003 to 2012.
Results
Over the 10-year surveillance period there were 242 cases of leprosy reported to the central public health office in the Saudi MoH (Table 1). Most cases (98.3%) were in persons post puberty (≥15 years old) with 162 cases (67%) in those aged between 15 and 44 years of age. No cases were identified in children less than 1 year old. Seventy-seven% of cases were in males, and 57% of cases were in non-Saudi nationals. PB leprosy accounted for slightly more cases than MB at 51%. Most cases (75%) were
Discussion
In our study of the leprosy surveillance system for the KSA for the 10-years period of 2003–2012, we found that the total of number of reported leprosy cases was only 35% of the total number of cases reported during a similar period of 1995–2005; 242 versus 683 [14]. And was only 31% of the 792 cases reported during the 4-year period between 1986 and 1989 [17]. The incidence rate per 10,000 ranged from a low of 0.005 in 2009 and 2102, to a high of 0.018 in 2003, with a mean of 0.096. Given that
Funding
None.
Conflict of interest
None to declare.
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College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.