Leishmaniasis

Leishmaniasis is a disease found in the tropical jungles of America, as well as in Asia and Africa. Actually, leishmaniasis is a group of diseases caused by different species of the Leishmania parasite, which is divided, according to the medical point of view, into superficial leishmaniasis that mainly affects the skin and mucous membranes, and visceral leishmaniasis, also called kala-azar, that harms the internal organs (liver, spleen, bone marrow). This disease is potentially fatal if left untreated.

Leishmaniasis can be divided into three groups:

• Cutaneous leishmaniasis (CL) causes nodules on the skin infected with the parasite.

• Mucocutaneous Leishmaniasis (MCL) causes ulcers and erodes the mucous membranes and cartilage.

• Visceral Leishmaniasis (VL) is a severe form in which the parasite migrates to the vital organs.

This disease is a serious public health problem, because like Chagas disease, it generates a high rate of morbidity and mortality in the population. Currently, there are approximately 12 million people infected with Leishmaniasis worldwide, however many cases are never reported. Leishmaniasis belongs to the group of diseases associated with poverty, mainly because the people who are infected live in remote areas, but also because they suffer a social stigma due to the facial disfigurement or very noticeable scars caused by this disease. Ultimately, these people suffer permanent psychological damage that impels them to remain hidden. This means that although superficial leishmaniasis is not usually fatal, it can cause the patient's social death.

In 1968, Dr. Jacinto Convit joins research groups to study Leishmaniasis. During his research, he demonstrates that when Cutaneous Leishmaniasis (CL) develops, there is an immunological defect of the patient. This defect was determined to be more related to the disease than other aspects such as the parasite variations, adaptations or mutations, without denying the obvious effect of different parasite strains and other particular features of the parasite. Assuming this concept, of a defect in the immunological system of the patient when developing CL, Dr. Convit started searching preventive methods against the disease and insisted that the patient and his living environment had to be accurately evaluated. This led Dr. Convit to advise international institutions that Leishmaniasis was more than a forgotten disease, as it was known, it was a disease of forgotten people, who lack of good and proper attention. This aimed to develop a new perspective of the health system.

Additionally, Dr. Convit's vision on this new concept of CL development, led him to use the leprosy vaccine as a model to develop a vaccine for Leishmaniasis. So he used a mix of dead Leishmania promastigotes harvested from in vitro cultured parasites plus viable BCG. The effectiveness of the vaccine was mainly evaluated in the localized CL form (LCL), as this was the most frequent form of the disease and the most probable to show an adequate immunological response of the patient to the immunotherapy. Between 1990 and 1999, the experimental application of the vaccine in Venezuela on patients with diagnosed CL, gave rise to the cure of most of the patients, a total success. Hence, a very unexpensive and with no secondary effects vaccine was created, contrary to the chemical drugs that were used.

The main objective of the Foundation is to support the massification and distribution of Dr. Convit's vaccine against leishmaniasis in Venezuela and in other countries affected by this disease, such as Central American countries where Dr. Convit was already applying his vaccine and seeing excellent results.

Additionally, the Foundation aims to include testing of this disease under its Molecular Diagnostic Unit in order to contribute to an early and personalized diagnose of the affected population. At the same time, the Foundation aims to develop new lines of research in this area that include molecular epidemiological studies of the parasites, as well as other therapeutic alternatives for the disease.

¿How do people get Leishmaniasis?

The protozoan parasite is transmitted by the bite of the sand fly or phlebotome of the genus Phlebotomus or Lutzomyia. These insects inhabit humid areas where the average temperature is 20� C, and usually bite any exposed area of the body. Transmission occurs when a sand fly bites an infected mammal, and the now infected sandfly innoculates the parasites into a healthy host through its bite when it tries to feed on the host's blood.

Phlebotomus or Lutzomyia

There are different forms of leishmaniasis:

Cutaneous leishmaniasis affects the skin and mucous membranes. Skin sores usually start at the site of the sandfly bite and can last months or years before they heal by themselves. In a few people, sores may develop on mucous membranes.

Systemic, or visceral, leishmaniasis affects the entire body. This form develops in 2 to 8 months after a person is bitten by the sandfly. Most people do not remember having a skin sore. This form can lead to deadly complications if left untreated. The parasites damage the immune system by decreasing the numbers of disease-fighting cells, thus further weakening the patient.

¿How is Leishmaniasis treated?

The main drugs used to treat leishmaniasis are antimony-containing compounds which include Meglumine antimoniate, Sodium stibogluconate.

However, the immunotherapy or vaccine designed by Dr. Convit, has proven equally effective as the conventional treatment while minimizing the toxic effects and costs much less. This vaccine is currently managed by the Institute of Biomedicine, therefore any information regarding this treatment and its distribution is managed by them. This treatment has also been implemented in parts of South America and Central America.

¿What should I do if I suspect I have Leishmaniasis?

Contact your physician. If you live in the countryside you can ask for the nearest Sanitary Dermatology Service to be examined by their specialists. If you live close to the metropolitan area, you can go to the Institute of Biomedicine Dr. Jacinto Convit to get immediate assistance.

REGIONAL HEALTH SERVICES DERMATOLOGY (UPDATED SEPTEMBER 2019)