The best way to prevent the spread of leprosy is to treat all patients with multidrug therapy. MDT kills the bacteria and stops the spread of the disease.
The mechanism of infection is not fully understood but it is generally thought to be by droplet spread through the upper respiratory tract. The incubation period is long, usually between two and eight years but it can be up to 20 years in some cases.
Casual contact with a person affected by leprosy does not seem to lead to infection. The evidence suggests that living for several years in an endemic area increases the risk of infection. The current strategy to control leprosy involves early diagnosis and treatment with multidrug therapy with the overall aim of stopping transmission of the disease to new contacts.
An effective strategy to prevent the spread of leprosy is to diagnose all patients early in the disease and treat them with MDT. MDT kills the bacteria and stops the spread of the disease after the treatment has started. However, transmission may occur before treatment has started and so early detection is essential. The development of a diagnostic test to detect early leprosy before it becomes clinically apparent is an exciting new development in reducing transmission.
For further information please read Ishii, Norihisa MD PhD. (2003). Recent advances in the treatment of leprosy. Dermatology Online Journal, 9(2). Retrieved from: http://escholarship.org/uc/item/1td1j7ft
Chemoprophylaxis and vaccination
There are other methods to prevent the transmission of leprosy: chemoprophylaxis and vaccines. Chemoprophylaxis given as a single dose of antibiotic to contacts of new cases has been shown to reduce the incidence of leprosy and there are pilot projects under way in many countries to introduce this in regular programmes. BCG(1) is also effective at preventing leprosy by boosting immunity. It is given at birth in many countries and also to contacts of people affected by leprosy in a number of countries. Early vaccine trials are underway to test a new vaccine for leprosy.
1 Bacillus Calmette-Guerin vaccine which provides protection against tuberculosis and other illnesses.