Global and regional annual 'new case detection' of leprosy reported by World Health Organization.

Ministries of Health from endemic countries report ‘new cases detection’ (NCD) of leprosy to the World Health Organization (WHO) yearly. The number of countries reporting varies so making comparisons between one year and another, and between the rates unreliable. However, the numbers of new cases detected and reported are the main indicator of the global leprosy burden and also the main indicator of disease incidence. The Weekly Epidemiological Record (WER) publishes these data periodically and references are reported below. – 9 At global level data are available from 1985 to 2006 (Figure 1). The analysis of the global annual NCD of leprosy reported by WHO shows that this indicator has been relatively stable between the years 1985 and 1997 varying between 550,000 and 700,000 cases. Two major peaks were reported in 1998 and 2001; this last one with 763,262 new cases registered. Since 2001 there has been a steady decrease with 259,017 cases reported in 2006 (Table 1). The analysis of the regional data of the same indicator is possible for a shorter period, from 1991 to 2006 and shows differences. Leprosy is still an important public health problem in three WHO regions, namely South-East Asia, the Americas and Africa. The South-East Asian region reports the highest number of newly detected leprosy cases; 67% of the global cases are here. The annual trend in this region is very similar to the global one (Figure 2). Two major peaks occurred in 1998 and in 2001; this last one with 668,658 new cases registered. Since then a steady decrease has taken place, with 174,118 cases reported in 2006 (Table 1). Leprosy is a disease that includes among its characteristics chronicity, very long incubation time, subtle early symptoms and signs, and difficult to establish time of onset of the disease. Often when anti-leprosy treatment is started patients have already released in the environment leprosy bacilli that may cause new cases later on, so one expects that the impact of treatment on reduction of NCD would be slow. The decrease reported in South-East Asia from 2001 to 2006 is faster than expected and needs to be studied further. In this region 80% of the cases are in India. Figure 3 shows the annual leprosy NCD trend in this country. Also here two major peaks are evident in 1998 and in 2001 and then a steady decrease. Lepr Rev (2008) 79, 124–127