Colombian National Army Develops Methodology to Fight Leishmaniasis
By Dialogo March 04, 2016
Colombian Troops are constantly exposed to the mosquito that transmits leishmaniasis, a disease whose clinical manifestations range from scarring cutaneous ulcers to severe inflammation of the liver and spleen. The World Health Organization (WHO) estimates that every year there are 1.3 million new cases and 20,000 to 30,000 deaths related to the disease worldwide.
Cases of leishmaniasis have been widespread in Latin America, particularly in Colombia, Peru, Bolivia, and Brazil. In Colombia, the National Army has reported an average of 4,000 to 5,000 new cases annually.
Early detection of the disease is important to allow for the appropriate prognosis and follow-up treatment. Lieutenant Colonel Claudia Méndez, who heads the Army Health Directorate Research Center's laboratory, develops tools to improve diagnosis, optimize the monitoring of patients, and reduce the adverse effects related to treatment of the disease, such as myalgia, arthralgia, and impaired liver function, among others.
“Cutaneous leishmaniasis is the most common disease transmitted by insect vectors to Soldiers in Colombia, well above zika, chikungunya, chagas disease, dengue and other diseases,” Lt. Col. Méndez said. “While it is not fatal, it affects the Troops because it leaves scarring lesions on the face and other parts of the body. If not treated in time, the parasite can advance and produce mucocutaneous leishmaniasis, which deforms and pierces the septum, and damages the lining of the mouth, among other symptoms."
Lesions within three weeks
After being bitten by the mosquito that carries the disease – the Lutzomyia Psychoidae
– one to three weeks will pass before the development of a papule that can grow from 0.5 to three centimeters in diameter. Most patients have one or two of these lesions on their face, hands, or legs.
Samples to determine the disease's existence should be taken by a direct swab and analyzed by a microscope, according to Lt. Col. Méndez. However, platoons do not always have a bacteriologist who can perform the procedure and accurately diagnose patients, often making cases hard to diagnose.
“When the papules are present but the test for leishmaniasis is negative, the patient needs to go to the nearest town, where a biopsy is taken," Lt. Col. Méndez said. “The samples are then sent to the Military Hospital in Bogotá. This process takes about three weeks and is very expensive. It also causes a very slow recovery in patients.”
Lt. Col. Méndez and her team implemented an innovative procedure to address this issue. “In places that are difficult to access, combat nurses are trained to take the sample on filter paper,” she explained. “The patient takes the filter paper out of a hermetically sealed plastic bag, makes an imprint on the leishmaniasis lesion, and sends it to our laboratory in Bogotá. In two days, we have the diagnosis ready.”
The new methodology featuring Conventional Polymerase Chain Reaction (PCR) technology was implemented in 2012. And in June 2014, real-time PCR was added, greatly simplifying the diagnosis of leishmaniasis among Colombian Troops.
The medication used to treat the disease can cause harmful effects. In Colombia, physicians treat leishmaniasis with Glucantime, a medicine whose toxicity can cause myalgia, arthralgia, weakness, and vomiting, and if used for a prolonged period, kidney and heart damage.
Lt. Col. Méndez's research is focused on the quantification of the parasite load in cutaneous leishmaniasis through real-time PCR to characterize the circulating strains of Leishmania and determine the effective treatment for each patient. PCR is a molecular technique that utilizes the parasite’s DNA to obtain very specific results.
In the case of Colombia, there are different strains of reference: L.braziliensis, L.panamensis, L.guayanensis, L.colombiensis, L.amazonensis, L.mexicana,
. Based on the displacement speed of each one at different temperatures during the test, it is possible to determine the species of Leishmania that is affecting the patient.
“We work with real-time PCR," Lt. Col. Méndez stated. "This methodology allows us to quantify and identify the parasites in each patient and determine whether Glucantime treatment will be effective. We monitor them from day 0 to day 10 and on day 20 of the treatment, and establish a timeline for the behavior of parasites at the molecular level. If the patient is resistant to treatment, we can provide alternatives.”
Pentamidine and Amphotericin are some alternative treatments that doctors can prescribe instead of Glucantime. This dual functionality of the PCR methodology for leishmaniasis, species identification, and parasite quantification, has involved analyzing samples from 200 patients at the Research Center. In April, the study is scheduled to run with funding from the Army’s Office of Education and Doctrine.
Leishmaniasis in Latin America
Leishmaniasis is linked to environmental changes such as deforestation, dam construction, irrigation systems, and urbanization, according to the WHO. In the Americas, cases have been reported everywhere from northern Argentina to southern Texas, with the exception of Chile and Uruguay.
Leishmaniasis covers a group of diseases caused by a parasite belonging to the genus Leishmania. The main forms of leishmaniasis are visceral (the most severe), cutaneous (the most common), mucocutaneous, disseminated, and diffuse. Leishmaniasis is a zoonosis (a disease transmitted from vertebrate animals to humans), which is transferred through the bite of an insect vector.
Human infection can occur through parasites from an animal source (zoonotic cycle) or through parasites from another human host (anthroponotic cycle). Dogs are the most common hosts of cutaneous leishmaniasis, though it is also present in other small mammals. Due to the proximity of Soldiers to canines during humanitarian demining and other activities, it is important to also treat animals, who are cared for by the National Army’s veterinarians.
Good day I suffered from leishmaniasis I was ill a year and a half here there are vaccinations Maracaibo and Trujillo they are made here the parasite doesnâ€™t exist any more thank you