Leprosy is a contagious bacterial disease. Although 95% of the world’s population has a natural immunity to the germ responsible for the disease, that still leaves 5% (more than 350 million people) susceptible to this curable, yet chronically disabling disease. Although researchers and experts still don’t completely understand leprosy, they do have a pretty good handle on it. Here’s a look at the transmission and causes of leprosy.
What Bacteria is Responsible for Leprosy?
Leprosy is also called Hansen’s disease, in homage to the doctor who first saw the microscopic germ. Mycobacterium leprae is thought to be passed through droplets that spread when the infected person coughs or sneezes -- although exactly what happens isn’t completely understood. Additionally, leprosy has an extremely lengthy incubation period. It can take decades before signs of leprosy first appear, which means you may be coughing and sneezing bacterium all over the place without even realizing it.
How is Leprosy Transmitted?
Leprosy is not highly contagious in the way that infections with the potential of turning into an epidemic are. Most people don’t become infected simply by touching doorknobs an infected person touched or being in a waiting room near someone with Hansen’s disease, but rather because of long-term contact with someone who has contracted the disease, but is likely still unaware of the fact. Because of this, you could say the incubation period of leprosy is when it poses the most dangerous for others -- although for those already infected, the later symptoms are by far the most incapacitating.
What Are the Types of Leprosy?
The two most common types of leprosy are tuberculoid and lepromatous, the latter of which the most severe. Rather than developing as a result of two different strains of bacteria, they develop as a result of the infected person’s immune system. Stronger immune systems tend to develop tuberculoid type, while a less effective immune response results in lepromatous type. Clinically, the Ridley-Jopling system is used to diagnose leprosy based on six different classifications, depending on the severity of symptoms.
What Are the Chances of Contracting Leprosy?
Less than 100 cases of Hansen’s disease were reported in the United States in 2015, and mostly in states that stay warm much of the year (such as Hawaii or California). Of the countries with more cases of Hansen’s disease, most of these are temperate and tropical areas. In 1991, the World Health Organization (WHO) started a campaign to eradicate leprosy which has been largely successful. In fact, WHO states that over the past 30 years, “the prevalence rate of the disease has dropped by 99%: from 21.1 per 10 000 in 1983 to persons to 0.24 per 10 000 in 2014.”
Nonetheless, one of the more frightening aspects of modern leprosy is the resistance to antibiotics that has been developing amongst the microbes in recent years. The treatment approach to curing leprosy is multidrug therapy (MDT), in which a variety of different antibiotics are given at the same time. This had been working well, until the bacteria began to evolve. Although this has caused a slight increase in the amount of people who develop leprosy in some areas of the world, ultimately leprosy is still well controlled.
