**1. Introduction**

Mycobacterium leprae (*M. leprae*) is an acid fast bacilli that is the causative agent of leprosy disease which mainly effects the skin and peripheral nerves. In olden times leprosy was common in temperate climates (e.g. Europe), today it is mainly confined to tropical and subtropical regions. Mode of transmission in leprosy is mainly through inhalation of droplets containing the bacteria. But skin contact is also claimed by many leprologists. The disabilities and deformities associated with leprosy due to neuropathy leads to long-term consequences, including. This in turn is associated with stigma.

The immunity of the host plays an important role in disease progress and control. Thus, fortunately 95% of patients exposed to *M. leprae* will not develop this disease. The variation in incubation period ranges from 2 to 20 years, or even longer.

Leprosy has been successfully eliminated as a public health problem in 2000 globally and at the national level in 113 countries out of 122 by 2005 [1]. Elimination of leprosy is defined by World Health Organization as a point prevalence below 1 per 10,000 population [2]. However, the number of new patients diagnosed with leprosy is still significant, at more than 200,000 in 2016 globally. The new case detection rate of the disease (NCDR) is only slowly declining (**Figure 1**) [3].

The long incubation period, silent symptoms, long duration MDT and unavailability of effective vaccine makes this disease difficult to identify, treat and eradicate. To add to the misery the stigma associated with the disease is another challenge. In such circumstances, prevention and control of disease gains utmost importance.

#### **Figure 1.**

*Trend in case detection and case detection rate, by WHO region, 2006–2016 [3].*

## **2. Burden of disease**

In 2017, 192,713 patients were on treatment globally which makes the prevalence rate of 0.25 per 10,000 population [4]. Total of 210,671 new cases were reported in same year from 150 countries making NCDR of 2.77 per 100,000 population. **Figure 2** below shows the trends over the past decade (2008–2017) in new case detection of leprosy cases globally in the reporting countries of World Health Organization (WHO) [4].

**133**

*Leprosy: Prevention and Control*

**3. Control of leprosy**

1.Medical measures

3.Program management

**4.1 Estimation of the burden of leprosy**

2.Social support

4.Evaluation

**4. Medical measures**

**4.2 Early Case Detection**

*DOI: http://dx.doi.org/10.5772/intechopen.92089*

The three main goals of control of leprosy are

b.To prevent the transmission to the others.

c.To prevent the disabilities and other complications.

a.To detect the pathology early and treat the patient completely.

Thus the following modalities are adopted to control leprosy:

The control of leprosy starts with the estimation of size and magnitude of the problem. Most common epidemiological survey method of collection of data is "Quick random sample survey." Information about the prevalence of leprosy, age and sex-wise distribution, various forms of leprosy and the health facilities available should be gathered. Roughly the total prevalence of leprosy in an area would be about 4 times that of the cases found among school children [5, 6]. These estimates are essential to plan, implement and to evaluate the results of the control program.

The objective is to detect all the cases as early as possible and to register them. Active case finding is important as the disease is symptomless in the early stages. Cases can be detected by the Contact surveys, Group surveys and Mass surveys. Contact surveys consists of examination of all household contacts with a lepromatous case, particularly children, in areas with prevalence less than 1 per 1000. Contact surveillance of households is recommended for a minimum period of 10 years after case is declared bacteriologically negative, and for 5 years in households with a non-lepromatous case from the time of diagnosis of the index case. Group surveys are done in areas where prevalence of leprosy is more than 1 in 1000 population. This consists of screening certain groups such as school children, slum dwellers, military recruits, industrial workers, etc. through "Skin camps." Lastly, mass surveys consists of examination of each and every individual by house-tohouse visits in hyperendemic areas (prevalence – 10 or more per 1000 population). These are generally carried out by repeated annual examinations of school children which yield better results at relatively low cost [5, 6]. The data of each case is

entered in the standardized proforma developed by WHO.
