**4. Vaccines against Leishmaniasis**

**Structural form Chemical/commercial name**

382 Leishmaniasis - Trends in Epidemiology, Diagnosis and Treatment

Pentamidine Isethionate [13]/

Amphotericin B [13]/ Fungizone

Paromomycin [13]/ Humatin

Lomidine

Miltefosine [21]

**Table 3.** Other chemicals used in leishmaniasis therapy, with their respective chemical and commercial names.

Association of some drugs used in leishmaniasis treatment within lipid vesicles called liposomes is one of the alternatives used to reduce the undesirable effects. This association increases the efficiency and the concentrations of these drugs in the tissues, reducing drasti‐ cally their toxicity [22, 23]. The mechanism that could explain the effectiveness of liposomes

One practical exemple of this association happens with Amphotericin B, a compound used for the treatment of calazar patients that are resistant to pentamidine. Amphotericin B can be toxic because they can associate with human cell cholesterol as they do to the ergosterol in the parasite plasmatic membrane [6]. To reduce this inappropriate recognition, there are some commercial formulations that associate the Amphotericin B to lipids (Ambisome, Abelcet, Amphotec). Besides their effectiveness in reducing this drug toxicity, they are very expensive

However, there are some studies searching some low-cost methods of producing these drugs. One example is a formulation with a similar lipid composition to Abelcet, but with some different variables, such as conformation and molecular weight, that may influence the drug release and action in the organism [26]. This formulation was found to be much more effective and less toxic than Abelcet and, although it is less efficient than Ambisome, it is also less

is that they inhibit oxygen consumption by the parasite membrane [24].

and their use becomes basically impractical in poor countries [25].

expensive for use in leishmaniasis treatment.

**3. Alternative treatments**

Studies for the achievement of a vaccine for leishmaniasis immunization are accomplished since 1940 [27]. In the firsts vaccination process against this disease, scientists didn't know that they were dealing with a microbian ill. This vaccine method was based in the injection of the active wound secretion from one patient to another that was not ill.

From this vaccine, other techniques were developed aiming the raise of the prophylactic efficiency and to avoid some troubles caused by the emergence of a wound. Thus, specialized literature reports four types of vaccines against different types of leishmaniasis: the vaccine based on dead parasites, the vaccine based on living but attenuated parasites, the vaccine with antigenic fragments, and the genic vaccine based on DNA [28].

In a few countries, some clinical trials were already performed but none of the vaccines showed a level of efficiency higher than 80%, a fact that makes unfeasible human tests. This lack of security may be associated to the differentiation between *Leishmania* species [29], and this differentiation hampers the accomplishment of a wide immunization field.

New investments to the manufacture of a vaccine against leishmaniasis depend on an active biomass of these protozoa. This way, when in contact with the target it may generate an immunological response without generating the disease. But nowadays, the methods for obtaining this biomass [30, 31] are very expensive with low profitability, since it generates a very small sample with an inefficient outcome.
