Spotlighting Leprosy's Stealthy Return in 28 Mexican States

Leprosy is an infectious and curable disease; with proper detection and care, the patient can be prevented from having disfiguring or disabling lesions, says María del Rosario Morales Espinosa, an academic from the Department of Microbiology and Parasitology of the UNAM School of Medicine.

She stresses that it has not been eradicated and in Mexico there are cases in 28 states, so the population must be aware of its existence. Doctors should also be prepared so that, starting at the first level of care, they can identify it, adds the specialist on the occasion of World Leprosy Day, which is commemorated on the last Sunday of January.

In addition, it is possible to prevent it by monitoring patients' contacts. One person can have thousands in a certain period of time, which is why epidemiological studies are necessary: to locate the patient, find out which places and who they visited, and guide them as to what to do if they present any type of lesion, to rule out that it is the result of leprosy infection, she explains.

Last year, the Ministry of Health issued an alert in the country because at the end of 2022 it registered 618 cases in post-treatment surveillance and 300 in treatment, in 28 states of the Mexican Republic. In seven of them -Jalisco, Michoacán, Morelos, Nuevo León, Oaxaca, Sinaloa and Yucatán- there were municipalities with a prevalence rate higher than one case per 10,000 inhabitants.

Morales Espinosa affirms that they are lower than those detected in previous decades, but what increased was their prevalence, indicating that it is tending to rise.

Another problem, he says, is that during the COVID-19 health emergency, leprosy was one of the many diseases “that were forgotten”.

Its diagnosis is not simple because the signs and symptoms can appear five or even 20 years after being in contact with a person with the disease and can be confused with any skin lesion. One may think that one does not have it, but it is incubating, and when it appears, the disease has already been established, she warns.

The UNAM academic explains that not all the patients' contacts develop it, but only the most susceptible ones, for example, those who have a compromised immune system with a debilitating disease such as cancer, immunosuppression syndromes, chronic degenerative diseases such as diabetes, and children, since their immune system is not at its full potential.

“This disease is produced by the bacterium Mycobacterium leprae and is very slow growing. Transmission is by close contact, although it is not known exactly whether it is through skin-to-skin or skin-to-mucosa contact. Some authors even indicate that quantities of bacilli are shed through secretions from the nose and can be inoculated through the skin or mucous membranes,” he points out.

One of the first manifestations are skin lesions, which are usually discolored, reddish spots or with active borders, but the warning sign is the lack of sensitivity in the area.

Depending on the progress of the disease, the bacillus can invade more deeply or to the sides of the tissue; if it invades the sebaceous glands, the lesions will appear dry; if the sweat glands are affected, moisture is lost in the affected area; the bacillus has an affinity for the nerve trunks, resulting in thickening of the affected trunks and, therefore, loss of sensitivity in the entire area that they innervate.

“If leprosy is suspected and one is in an area where there are cases, any skin lesion should be explored to determine whether sensitivity is present or absent, the first thing that is lost is sensitivity to heat or cold and then to pain. If there is a suspicion of a lesion caused by leprosy, the person should be referred to a specialist at a dermatology center for further confirmation studies”, adds the university expert.

There are countries where these patients are still stigmatized, such as in India or in parts of Africa or Asia. This is since, by losing sensitivity, the person can self-inflict wounds that he/she does not notice because they do not hurt and result in mutilations that aggravate his/her appearance.

In Mexico, the expert explains, the most common type of leprosy is tuberculoid and is, to a certain extent, benign leprosy. “This depends on the individual's competent immune system, which allows controlling the replication of the bacillus by confining it to a granuloma and without so much tissue destruction”.

There is also lepromatous leprosy, he continues, which is the malignant form; it manifests more frequently in continents such as Africa and Asia. Patients have a hyporeactive immune system, so there is no control of the bacillus, which generates lesions in the form of grains or mounds with numerous bacilli and involvement of tissue, nerves, bones and cartilage, causing deformities, especially in the pinnae of the ears, the nasal septum, the distal phalanges of both hands and feet.

It is based on drugs, depending on the type of leprosy and its evolution. “Basically, there are two drugs combined, and it must be given under surveillance. They are administered for up to 12, 24 months, depending on the severity of the disease,” he says.

After five or six months, the lesions begin to disappear, and it is common for patients to abandon the treatment, given how long it takes. However, it is important to finish it, since there may be reactivation of the disease.

The UNAM academic comments that there is a network called TAE, of monitored and controlled treatment, where health personnel -either nurses and/or social workers or social workers, even doctors-supervise that the patient takes the medication and, on occasions, they schedule an appointment at the health center; if they do not go, they look for them at home.

“We have to prevent this disease and once it is diagnosed, give treatment, but not forget it because if we do, when we least expect it, we are going to have a multiplication of cases. Leprosy can be prevented, controlled and cured,” he insists.

This disease, recalls Morales Espinosa, has accompanied human beings throughout their evolution, it is documented in biblical passages in which it is mentioned how society behaved with these patients, they were confined to certain places.