When a group of travelers get together, there are a lot of stories and helpful tips shared. A favorite cafe, a hotel with a great location and places to visit are always on the top of the list. I rarely hear people discussing leishmaniasis and this is the point of a recent article in the Emerging Infectious Diseases journal. This illness is becoming more and more prevalent, especially in Southern Europe and the Mediterranean, and is an infection that most travelers know little about.
If you are just hearing about leishmania for the first time, here is a quick run down:
Basics: Two main types of this disease exist, cutaneous (aka Baghdad boil) and visceral (aka Kala Azar). Visceral disease primarily involves the liver and spleen with fever while the cutaneous form is known for blisters and poorly healing skin sores. Different species of Leishmania are geographically based. The life-cycle is complex and often relies on multiple hosts. Approximately 2 million new cases per year are estimated.
Location: New World Cutaneous Leishmaniasis is found in Central and South America (Mexico, Guatemala, Belize, Brazil, Venezuela, Ecuador, Peru, Honduras, Colombia and Costa Rica) in rural forests. Old World Cutaneous Leishmaniasis is found in the Middle East, Mediterranean Basin, Southwest Asia, and Sub-Saharan Africa. Visceral Leishmaniasis can be seen in the Mediterranean basin, India, China, East Africa, Central and South America.
Transmission/ Incubation: Acquired from the bite of an infected Phlebotamine Sandflies. Dogs and rodents are primary animal reservoirs. A 2-6 month incubation from infection to cutaneous nodules/lesions is observed. Visceral forms can have a 2-8 month incubation.
Prevention: Vector and reservoir control, prevention of insect bites
Diagnosis: Demonstration of organism in smear of cutaneous lesion or bone marrow biopsy showing amastigotes in visceral form of disease. The Montenegro skin test is positive in chronic infection.
Treatment: The drug class to know is “Pentavalent Antimonials”. Generally a self-limited disease, cutaneous leishmaniasis treatment has to be compared to the toxicity of the medicine. Stibogluconate (Pentosam) 20mg/kg/day for 3 weeks is standard and can be given IM or IV. Ketoconazole has also been shown to be effective as second line treatment, along with Pentamidine. Cryotherapy (freezing) and surgical excision for early lesions may reduce scarring. For visceral leishmaniasis, stilboglucaonate is also used at the above dose but given IV for 28 days.
So, now that we are all on the same page with the illness, back to the article. The authors point out that the majority of cases, in Southern Europe, are of the visceral form (most severe). Given the recent increase in vector borne illnesses in Europe, such as Chikungunya virus in Italy, this parasite needs to be recognized as an “up and coming” issue in Europe.
Anyone who has spent some time in the European side of the Mediterranean Basin can attest to large amounts of dogs and cats. These aren’t exactly wild and they don’t really belong to one person. They are a kind of “town pet” that is looked after by many people who live nearby. This is part of the culture and charm of the area. This is also one of the major ways leishmania can survive. In fact, the authors of this particular article cited a separate source that found the way Leishmania was imported to South America was with the pet dogs of the conquistadors!
Parasites require vectors to travel around. These vectors are the sand flies, in the case of leishmania. There are many different species of “sand flies” and not all are capable of carry the parasite. However, as in the case of P. Papatasi, a fly commonly found in Europe, studies have shown it to be a carrier. Thus, a potentially new carrier of leishmaniasis is primed and ready to assist with spreading the disease futher accross Europe.
One other concerning point raised was of the possibility of drug resistence. A drug called Miltefosine was recently approved for treatment of dogs in Portugal, Spain, Italy, Greece and Cyprus. The authors suggest that due to the long half-life of the drug and the fact that dogs are never fully cleared of the parasite, drug resistence may emerge. This could render a very powerful medicine useless to treat humans infected with leishmaniasis. Some species of leishmania have already become resistent to antimonial drugs, in certain areas. Antimonial drugs are considered a “first-line” treatment.
There is a saying in medicine that goes, “If it is not in your differential, you cannot diagnose it”. Basically, you have to be thinking about something to find it. Clinicians and travelers alike do not commonly consider the risks of leishmaniasis in Europe. I feel that it is a risk and should be considered by any traveler in the areas. A very cool site: www.Leishrisk.net can give some more information on treatments and control methods. Also, a big thanks to the authors of the article: Spread of vector borne diseases and neglect of leishmaniasis, Europe for their efforts and a very thought provoking article.