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Leishmaniasis as an Emerging Infection

2001; Elsevier BV; Volume: 6; Issue: 3 Linguagem: Inglês

10.1046/j.0022-202x.2001.00038.x

1529-1774

Christine M. Choi, Ethan A. Lerner,

Trypanosoma species research and implications

Leishmaniasis is a protozoan disease whose diverse clinical manifestations are dependent both on the infecting species of Leishmania and the immune response of the host. Transmission of the disease occurs by the bite of a sand fly infected with Leishmania parasites. Infection may be restricted to the skin in cutaneous leishmaniasis, limited to the mucous membranes in mucosal leishmaniasis, or spread internally in visceral leishmaniasis or kala azar. The overall prevalence of leishmaniasis is 12 million cases worldwide, and the global yearly incidence of all clinical forms approaches 2 million new cases (World Health Organization WHO/LEISH/200.42, Leishmania/HIV Co-Infection in Southwestern Europe 1990–98: Retrospective Analysis of 965 Cases, 2000). In the last two decades, leishmaniasis, especially visceral leishmaniasis, has been recognized as an opportunistic disease in the immunocompromised, particularly in patients infected with human immunodeficiency virus. Leishmaniasis is a protozoan disease whose diverse clinical manifestations are dependent both on the infecting species of Leishmania and the immune response of the host. Transmission of the disease occurs by the bite of a sand fly infected with Leishmania parasites. Infection may be restricted to the skin in cutaneous leishmaniasis, limited to the mucous membranes in mucosal leishmaniasis, or spread internally in visceral leishmaniasis or kala azar. The overall prevalence of leishmaniasis is 12 million cases worldwide, and the global yearly incidence of all clinical forms approaches 2 million new cases (World Health Organization WHO/LEISH/200.42, Leishmania/HIV Co-Infection in Southwestern Europe 1990–98: Retrospective Analysis of 965 Cases, 2000). In the last two decades, leishmaniasis, especially visceral leishmaniasis, has been recognized as an opportunistic disease in the immunocompromised, particularly in patients infected with human immunodeficiency virus. cutaneous leishmaniasis human immunodeficiency virus mucocutaneous leishmaniasis visceral leishmaniasis The increases in travel and the number of immunocompromised individuals allows leishmaniasis to be considered an "emerging disease". The purpose of this paper is to highlight selected clinical, histopathologic, and immunologic features of leishmaniasis as well as therapies and vector biology. The cutaneous afflictions of leishmaniasis have been known since antiquity (Peters, 1988Peters W. Royal Society of Tropical Medicine and Hygiene presidential address. Manson House, 15 October, 1987. "The little sister" – a tale of Arabia.Trans R Soc Trop Med Hyg. 1988; 82: 179-184Abstract Full Text PDF PubMed Scopus (18) Google Scholar). Descriptions of the cutaneous disease in the Old World are found from the first century AD. New World pottery from Peru and Ecuador dating from AD 400–900 illustrates faces afflicted with a process consistent with leishmaniasis (Lainson and Shaw, 1987Lainson R. Shaw J.J. Evolution classification and geographical distribution.in: Peters Wkillick-Kendrick R. The Leishmaniases in Biology and Medicine. San Diego, Academic Press1987: 1-120Google Scholar). The first description in English of a lesion resembling leishmaniasis was made in 1756 by Russell, who described the "Aleppo evil" from Syria. In 1885, Cunningham observed organisms in macrophages from lesions of "Delhi boil" in India. A Russian army physician named Borovsky noted the protozoal nature of the organism in 1898 in biopsy specimens from skin lesions. In 1903 Leishman published his identification of the parasite in the spleen of an English private who had died of Dumdum fever in Dum-Dum, India in 1900. A few months later Donovan described identical organisms in a splenic puncture specimen from a living child. The distinctive histologic feature of this 2–5 µm parasite was the presence of both a nucleus and a smaller rod-shaped structure consisting of mitochondrial DNA called the kinetoplast. Ross named the parasite "Leishmania donovani" later the same year. Other names of leishmaniasis include Oriental sore, Aleppo evil, Delhi boil, Baghdad sore, Rose of Jericho, Chiclero's ulcer, uta, espundia (mucous form), forest yaws, Dumdum fever (visceral form), kala-azar, and black fever. Leishmaniasis in its various forms is present on all continents except Australia and Antarctica (Lerner and Von Lichtenburg, 1991Lerner E.A. Von Lichtenburg F.C. Case records of the Massacusetts General Hospital: a 21 year old woman with a persistent rash on the elbow after a sojourn in Central America (Leishmaniasis).New Engl J Med. 1991; 324: 476-485Crossref PubMed Google Scholar). LCL is widespread throughout the Old World and is primarily caused by the organisms Leishmania tropica and Leishmania major. New world LCL is endemic in Central and South America. Two independent species or "complexes" of parasites are responsible for New World LCL: Leishmania braziliensis and Leishmania mexicana. LCL usually affects unclothed parts of the body easily bitten by the sand fly vector, including the face, neck, and arms. New World leishmaniasis commonly presents with a solitary primary lesion, whereas multiple primary lesions are often found in Old World disease. After an average incubation period of 1 wk to 3 mo, a red papule appears that enlarges to a plaque or nodule. The lesion often develops into an ulcer, which is well circumscribed with a violaceous border. The ulcer base is granulomatous and crusted, and the margins are hypertrophic but without extensive undermining (Figure 1). Painless, rubbery subcutaneous nodules or cords rarely develop around the ulcer due to local lymphangitic spread of the organism. Draining lymph nodes may be enlarged and reveal parasites on biopsy (Al-Gindan et al., 1989Al-Gindan Y. Kubba R. el-Hassan A.M. Omer A.H. Kutty M.K. Saeed M.B. Dissemination in cutaneous leishmaniasis, 3. Lymph node involvement.Int J Dermatol. 1989; 28: 248-253Crossref PubMed Scopus (46) Google Scholar). Occasionally, inflammatory satellite papules and subcutaneous induration may develop around the primary lesion representing a reaction to local dissemination of the parasite or its antigenic products (Kubba et al., 1987Kubba R. El-Hassan A.M. Al-Gindan Y. Omer A.H. Kutty M.K. Saeed M.B. Dissemination in cutaneous leishmaniasis, 1. Subcutaneous nodules.Int J Dermatol. 1987; 26: 300-304Crossref PubMed Scopus (50) Google Scholar,Kubba et al., 1988Kubba R. Al-Gindan Y. el-Hassan A.M. Omer A.H. Kutty M.K. Saeed M.B. Dissemination in cutaneous leishmaniasis. 2. Satellite papules and subcutaneous induration.Int J Dermatol. 1988; 27: 702-706Crossref PubMed Scopus (40) Google Scholar). Itching and pain are mild, if present. The wound may become superinfected, leading to misdiagnosis. Between 1 and 36 mo, depending upon both the patient and the infecting organism, the ulcer spontaneously regresses leaving a scar with hypo- or hyper-pigmentation. Immunity is considered complete but one study in a Saudi Arabian population found subsequent re-infection in up to 10% of individuals (Killick-Kendrick et al., 1985Killick-Kendrick R. Bryceson A.D. Peters W. Evans D.A. Leaney A.J. Rioux J.A. Zoonotic cutanous leishmaniasis in Saudi Arabia; lesions healing naturally in man followed by a second infection with the same zymodeme of Leishmania major.Trans R Soc Trop Med Hyg. 1985; 79: 363-365Abstract Full Text PDF PubMed Scopus (36) Google Scholar). DCL is an anergic variant of LCL in which lesions are disseminated, resembling lepromatous leprosy. Infection may be caused by Leishmania aethiopica or, in Central and South America, Leishmania amazonensis. The disease usually begins with an initial primary lesion and then disseminates to involve other areas of the skin. The lesions are nonulcerative nodules full of parasites, which are often scattered over the limbs, buttocks, and face. Unlike lepromatous leprosy, there is no nerve involvement. The disease does not invade internal organs, but responds only partially to treatment and often relapses, becoming chronic. PKDL is primarily caused by Leishmania donovani and is endemic in East Africa and India. In Africa, PKDL occurs in up to 50% of patients recovering from visceral leishmaniasis (Zijlstra et al., 1994Zijlstra E.E. El-Hassan A.M. Ismael A. Ghalib H.W. Endemic Kala-azar in eastern Sudan: a longitudinal study on the incidence of clinical and subclinical infection and post-kala-azar dermal leishmaniasis.Am J Trop Med Hyg. 1994; 51: 826-836PubMed Google Scholar) The rash generally consists of discrete skin-colored or hyperpigmented papules on the cheeks, chin, ears, and extensor aspects of forearms. Most lesions heal spontaneously over a few months. In contrast to African PKDL, Indian PKDL occurs in 20% of patients approximately 1–2 y after recovery (Rees and Kager, 1987Rees P.H. Kager P.A. Visceral leishmaniasis and post kala-azar dermal leishmaniasis.in: Peters Wkillick-Kendrick R. The Leishmaniases in Biology and Medicine. vol. 2. London, Academic Press1987: 848-907Google Scholar). Small hypopigmented macules are usually the first manifestation of PKDL and these enlarge to form large irregular patches. Lesions are often bilateral and symmetrical. The pigmentary loss is never complete, and there is no pigment change in the hair overlying the lesions. Erythematous macules develop next, often on the face in a malar distribution, but may also develop in other areas, especially in the hypopigmented patches. Finally, soft, painless, nonulcerative, yellowish-pink nodules replace the hypopigmented and erythematous macules, and sometimes develop de novo. Nodules most commonly affect the face, earlobes, trunk, and genitalia, and less frequently occur on the hands and feet. Cases of PKDL are difficult to treat, requiring longer duration of systemic medication. Hypopigmented areas almost never completely repigment. MCL is most commonly reported in the New World (Abdalla et al., 1975Abdalla R.E. El hadi A. Ahmed M.A. El Hassan A.M. sudan mucosal leishmaniasis.Trans R Soc Trop Med Hyg. 1975; 69: 443-449Abstract Full Text PDF PubMed Scopus (27) Google Scholar;Marsden, 1986Marsden P.D. Muscosal Leishmaniasis ("espundia" Escomel, 1911).Trans R Soc Trop Med Hyg. 1986; 80: 859-876Abstract Full Text PDF PubMed Scopus (286) Google Scholar). Leishmania braziliensis is the most common etiologic agent although there have been several reports of mucocutaneous disease due to Leishmania panamensis, increasing the risk that travelers to Central America could potentially develop MCL (Melby et al., 1992Melby P.C. Kreutzer R.D. McMahon-Pratt D. Gam A.A. Neva F.A. Cutaneous Leishmaniasis: Review of 59 cases seen at the National Institutes of Health.Clin Infect Dis. 1992; 15: 924-937Crossref PubMed Scopus (85) Google Scholar). Fifty per cent of patients develop mucocutaneous lesions within 2 y of the initial cutaneous lesions, and 90% within 10 y (Figure 2). Approximately one-third of patients have no prior history of skin lesions. MCL typically affects a small percentage (approximately 3%) of individuals previously infected with L. braziliensis subspecies, although a prevalence as high as 34% in endemic areas has been reported (Kerdel-Vegas, 1982Kerdel-Vegas F. American leishmaniasis.Int J Dermatol. 1982; 21: 291-303Crossref PubMed Scopus (24) Google Scholar). Mucous membrane involvement probably develops due to hematogenous or lymphatic dissemination, or occasionally from direct extension of nearby skin lesions. The disease often begins in the nasal septum which becomes inflamed and infiltrated and subsequently perforates. Malnutrition and pneumonia are the leading causes of death in patients with MCL. Kala-azar or VL is a systemic disease caused by the dissemination of Leishmania donovani or Leishmania infantum. The advent of human immunodeficiency virus (HIV) has increased the population of individuals afflicted by VL and is discussed later in this report. Characteristic signs and symptoms include fever, splenomegaly, lymphadenopathy, emaciation, pancytopenia, and hyperglobulinemia. The primary lesion of VL is rarely seen but consists of a small erythematous papule sometimes referred to as a "leishmanioma". During the active period of VL a diffuse blackening of the skin appears that is the origin of the name "kala-azar", meaning "black fever". After an incubation period of 2–4 mo, VL runs an insidious chronic course until treated. Although the disease is associated with an increase in serum IgG and IgM, there is a depression of cell-mediated immunity that predisposes the host to multiple secondary infections (Haldar et al., 1983Haldar J.P. Ghose S. Saha K.C. Ghose A.C. Cell-mediated immune response in Indian kala-azar and post kala-azar dermal leishmaniasis.Infect Immun. 1983; 42: 702-707PubMed Google Scholar). Treatment is usually successful in the absence of immunodeficiency but relapses have been reported (Berman, 1997Berman J.D. Human leishmaniasis: clinical, diagnostic, and chemotherapeutic developments in the last 10 years.Clin Infect Dis. 1997; 24: 684-703Crossref PubMed Scopus (706) Google Scholar). One source of such relapses is the observation that parasites have been demonstrated to persist up to 11 y following clinical cure (Schubach et al., 1998Schubach A. Marzochi M.C. Cuzzi-Maya T. et al.Cutaneous scars in American tegumentary leishmaniasis patients: a site of Leishmania (Viannia) braziliensis persistence and viability eleven years after antimonial therapy and clinical cure.Am J Trop Med Hyg. 1998; 58: 824-827PubMed Google Scholar). Leishmania tropica, which had been thought to cause cutaneous disease exclusively, was found to be the causative organism in several cases of VL reported in soldiers of Operation Desert Storm returning from Saudi Arabia (Magill et al., 1993Magill A.J. Grogl M. Gasser R.A.J. Sun W.C.N. Visceral infection caused by Leishmania tropica in veterans of Operation Desert Storm.N Eng J Med. 1993; 328: 1383-1387Crossref PubMed Scopus (335) Google Scholar). The clinical presentations were distinct from visceral leishmaniasis caused by L. donovani and incuded high fever, malaise, intermittent diarrhea, and abdominal pain. Histopathologic studies reveal epidermal and/or dermal changes, depending on the type and stage of the disease (Kurban et al., 1966Kurban A.K. Malak J.A. Farah F.S. Chaglassian H.T. Histopathology of cutaneous leishmaniasis.Arch Dermatol. 1966; 93: 396-401Crossref PubMed Scopus (60) Google Scholar). The diagnostic histopathologic changes of leishmaniasis, however, are usually present in the dermis. There is a predominantly mononuclear dermal infiltrate consisting primarily of lymphocytes and histiocytes. The histiocytes may be filled with Leishman-Donovan (L-D) bodies, which are 2–4 µm oval encapsulated protozoa with a large peripheral nucleus and a smaller rod-shaped kinetoplast of mitochondrial DNA. L-D bodies are numerous in early lesions of LCL and PKDL, very abundant in DCL, but scanty in MCL, VL, and leishmaniasis recidivans, an unusual form of the disease not discussed here in detail. The lymphohistiocytic infiltrate is arranged diffusely in cutaneous forms of leishmaniasis, except in PKDL and leishmaniasis recidivans where well-organized granulomas are seen. Langerhan's epithelial giant cells may be present within the granulomas. Plasma cells may also be abundant, especially in MCL. The infiltrate extends from the upper to lower dermis, sometimes around a central necrotic zone where fibrinoid degeneration of vessels may be present. Immunophenotypic analysis of cell subsets in LCL lesions reveals an abundance of T cells with an activated phenotype, expressing interleukin-2 (CD25+), transferrin receptors (CD71+), or major histocompatibility complex class II molecules on their surface (Esterre et al., 1992Esterre P. Dedet J.P. Fremay C. Chevallier M. Grimaud J.A. Cell populations in the lesion of human cutaneous leishmaniasis: a light microscopical, immunohistochemical and ultrastructural study.Virchows Arch a Pathol Anat. 1992; 421: 239-247Crossref Scopus (48) Google Scholar). Equal numbers of CD4+ and CD8+ lyphocytes are present in LCL lesions. In addition, whereas the majority of T cells in control skin biopsies bear the TCR α β complex, 20%-30% of the T cells in early LCL lesions bear the TCR γ δ complex (Modlin et al., 1989Modlin R.L. Pirmez C. Hofman F.M. et al.Lymphocytes bearing antigen-specific gd T-cell receptors accumulate in human infectious disease lesions.Nature. 1989; 339: 544-548Crossref PubMed Scopus (500) Google Scholar;Lima et al., 1994Lima H. Vasconceles W. David J.R. Lerner E.A. American cutaneous leishmaniasis: In situ characterization of the cellular immune response over time.Am J Trop Med Hyg. 1994; 50: 743-747PubMed Google Scholar). The arthropod vector of all forms of leishmaniasis is the female sand fly (Swaminath et al., 1942Swaminath C.S. Shortt H.E. Anderson L. Transmission of Indian kala-azar to man by bites of Phlebotomus argentipes, ann. & brun.Indian J Med Res. 1942; 30: 473-477Google Scholar). The disease is transmitted by flies of the genus Phlebotomus in the Old World and in the New World it is transmitted primarily by Lutzomyia and rarely by Psychodopygus. The transmission cycle of the leishmania organisms requires an arthropod vector and a mammalian reservoir. The parasite assumes two distinct forms during the life cycle: an extracellular, flagellated promastigote form, and a nonflagellated obligate intracellular form called the amastigote. During the course of probing the skin, the sand fly injects saliva containing the promastigote form of leishmania. The promastigote is taken up by macrophages and transformed into the round amastigote form. The parasite then resides in the phagolysosome of the macrophage and proliferates despite the presence of lysosomal enzymes. When a sand fly bites an infected host, amastigotes taken up during the blood meal transform back to the promastigote form in the gut of the fly, completing the life cycle. In hyperendemic regions, such as Israel, Jordan, and Saudi Arabia, L. major promastigotes are occasionally recoverable from 20% to 50% of female sand flies, but in other areas less than 1% of sand flies are infected (Norton et al., 1992Norton S.A. Frankenburg S. Klaus S.N. Cutaneous leishmaniasis acquired during military service in the middle east.Arch Dermatol. 1992; 128: 83-87Crossref PubMed Scopus (38) Google Scholar). Humans are usually accidental hosts of leishmaniasis, because they live in endemic zones and are thereby exposed to infected sand flies. The zoonotic reservoir includes sloths, anteaters, rodents, foxes, and dogs. Transmission of leishmania infection occurs almost exclusively via the bite of an infected sand fly; however, other possible modes of transmission (e.g., direct contact) have been reported (Nanji and Greenway, 1985Nanji A.A. Greenway D.C. Leishmania braziliensis infection of the nipple.Br Med J. 1985; 290: 433-434Crossref PubMed Scopus (82) Google Scholar;Yadav et al., 1989Yadav T.P. Gupta H. Satteya U. Kumar R. Mittal V. Congenital kala-azar.Ann Trop Med Parasitol. 1989; 83: 535-537PubMed Google Scholar;Eltoum et al., 1992Eltoum I.A. Zijlstra E.E. Ali M.S. Ghalib H.W. Satti M.M. Eltoum B. el-Hassan A.M. Congenital kala-azar and leishmaniasis in the placenta.Am J Trop Med Hyg. 1992; 46: 57-62Crossref PubMed Scopus (83) Google Scholar). Leishmaniasis is characterized by a spectrum of disease phenotypes that corresponds to the strength of the host's cell-mediated immune response. Both susceptible and resistant phenotypes exist within human populations. For example, many people in endemic regions develop positive skin tests without ever manifesting signs of clinical disease. Spontaneously healing lesions are associated with positive antigen-specific T cell responsiveness, diffuse cutaneous and visceral disease with T cell nonresponsiveness, and mucocutaneous disease with T cell hyperresponsiveness. (Blackwell, 1992Blackwell J.M. Leishmaniasis epidemiology: all down to the DNA.Parasitology. 1992; 104: S19-S34Crossref PubMed Scopus (25) Google Scholar) Current research is focused on determining the extent to which this spectrum of host response to leishmaniasis is genetically determined. An extensive literature exists on the immunology of leishmaniasis. The reader is referred to this literature with respect to cytokines, T cells of the Th1 and Th2 subtypes, killer T cells, humoral responses, and nitric oxide. (Pirmez et al., 1993Pirmez C. Yamamura M. Uyemura K. Paes-Oliveira M. Conceicao-Silva F. Modlin R.L. Cytokine patterns in the pathogenesis of human leishmaniasis.J Clin Invest. 1993; 91: 1390-1395Crossref PubMed Scopus (325) Google Scholar;Bardaró and Johnson, 1993Bardaró R. Johnson W.D.J. The role of interferon-g in the treatment of visceral and diffuse cutaneous leishmaniasis.J Inf Dis. 1993; 167: S13-S17Crossref PubMed Scopus (101) Google Scholar;Kemp et al., 1993Kemp M. Kurtzhals J.A. Bendtzen K. et al.Leishmania donovani-reactive Th1- and Th2-like T-cell clones from individuals who have recovered from visceral leishmaniasis.Infect Immun. 1993; 61: 1069-1073PubMed Google Scholar;Assreuy et al., 1994Assreuy J. Cunha F.Q. Epperlein M. Noronha-Dutra A. O'Donnell C.A. Liew F.Y. Moncada S. Production of nitric oxide and superoxide by activated macrophages and killing of Leishmania major.Eur J Immunol. 1994; 24: 672-676Crossref PubMed Scopus (238) Google Scholar;Stenger et al., 1994Stenger S. Thuring H. Rollinghoff M. Bogdan C. Tissue expression of inducible nitric oxide synthase is closely associated with resistance to Leishmania major.J Exp Med. 1994; 180: 783-793Crossref PubMed Scopus (266) Google Scholar;Davidson, 1998Davidson R.N. Practical guide for the treatment of leishmaniasis.Drugs. 1998; 56: 1009-1018Crossref PubMed Scopus (102) Google Scholar;Lezama-Davila et al., 1998Lezama-Davila C.M. Isaac-Marquez A.P. Padierna-Olivos J. Aguilar-Torrentera F. Chapa-Ruiz R. Immunomodulation of Chiclero's ulcer. Role of eosinophils, T cells, tumour necrosis factor and interleukin-2.Scand J Immunol. 1998; 47: 502-508Crossref PubMed Scopus (10) Google Scholar;Maasho et al., 1998Maasho K. Sanchez F. Schurr E. Indications of the protective role of natural killer cells in human cutaneous leishmaniasis in an area of endemicity.Infect Immun. 1998; 66: 2698-2704PubMed Google Scholar;Etges and Muller, 1998Etges R. Muller I. Progressive disease or protective immunity to Leishmania major infection: the result of a network of stimulatory and inhibitory interactions.J Mol Med. 1998; 76: 372-390Crossref PubMed Scopus (40) Google Scholar;Jones et al., 1998Jones D.E. Elloso M.M. Scott P. Host susceptibility factors to Cutaneous leishmaniasis.Frontier Bioscience. 1998; 15: D117-D180Google Scholar;Herwaldt, 1999Herwaldt B.L. Leishmaniasis.Lancet. 1999; 354: 1191-1199Abstract Full Text Full Text PDF PubMed Scopus (1374) Google Scholar;Mossalayi et al., 1999Mossalayi M.D. Arock M. Mazier D. Vincendeau P. Vouldoukis I. The human immune response during cutaneous leishmaniasis: NO problem.Parasitol Today. 1999; 15: 342-345Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). In endemic areas, the diagnosis is often made on clinical grounds alone, based on the following observations: (a) small number of lesions (1–3); (b) lesions situated on exposed areas; (c) lesions present for a number of months; (d) lesions resistant to all types of attempted treatments, and (e) usually no pain or itching. Multiple diagnostic techniques are available. Historically, microscopy and culture have been the standard for diagnosis. A punch or wedge biopsy may be performed, preferably from the indurated border of a lesion and not from a necrotic center. A touch prep or Giemsa-stained tissue impression slide may be done on excised tissue, scalpel scrapings, slit skin smears, or dermal cells obtained using a root canal file. Fine needle aspiration of a lesion may be done after injection of sterile saline. In cases of suspected VL, splenic aspirates are used. Specimens from a biopsy or aspirate may be cultured on NNN blood agar (Nicolle's modification of Novy and McNeal's medium) or rabbit blood agar, with the growth of promastigotes apparent between 2 d and 2 wk. The identification of the specific species of parasite responsible for infection is important for the diagnosis of disease, evaluation of therapy, and prognosis. Consequently, a number of molecular biology techniques have been developed that are designed for species-specific identification of parasites within the genus Leishmania. Monoclonal antibodies (McMahon-Pratt et al., 1982McMahon-Pratt D. Bennett E. David J.R. Monoclonal antibodies that distinguish subspecies of Leishmaniasis braziliensis.J Immunol. 1982; 129: 926-927PubMed Google Scholar) and isoenzyme analysis (Kilgour et al., 1974Kilgour V. Gardener P.J. Godfrey D.G. Peters W. Demonstration of electrophoretic variation of two aminotransferases in Leishmania.Ann Trop Med Parasitol. 1974; 68: 245-246PubMed Google Scholar) have been used. Oligonucleotide primers based on kDaNA sequences have been used in the polymerase chain reaction (PCR) (de Bruijn and Barker, 1992de Bruijn M.H. Barker D.C. Diagnosis of New World Leishmaniasis: specific detection of species of the Leishmania braziliensis complex by amplification of kinetoplast DNA.Acta Tropica. 1992; 52: 45-58Crossref PubMed Scopus (212) Google Scholar;Katakura et al., 1998Katakura K. Kawazu S. Naya T. et al.Diagnosis of kala-azar by nested PCR based on amplification of the Leishmania mini-exon gene.J Clin Microbiol. 1998; 36: 2173-2177PubMed Google Scholar;El Tai et al., 2001El Tai N.O. El Fari M. Mauricio I. Leishmania donovani: intraspecific polymorphism of Sudanese isolates revealed by PCR-based analyses and DNA sequencing.Exp Parasitol. 2001; 97: 35-44Crossref PubMed Scopus (129) Google Scholar). Species identification has been achieved in a variety of ways, such as multiplexing and using nested PCR (Aransay et al., 2000Aransay A.M. Scoulica E. Tselentis Y. Detection and identification of Leishmania DNA within naturally infected sand flies by seminested PCR on minicircle kinetoplastic DNA.Appl Environ Microbiol. 2000; 66: 1933-1938Crossref PubMed Scopus (192) Google Scholar). The widespread clinical usefulness of these techniques remains to be implemented. Over the past decade, leishmaniasis has been increasingly documented in immunocompromised patients, namely those infected with HIV (Machado et al., 1992Machado E.S. Braga MdP Da Cruz A.M. et al.Disseminated American muco-cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis in a patient with AIDS. a case report.Mem Inst Oswaldo Cruz. 1992; 87: 487-492Crossref PubMed Scopus (55) Google Scholar;Gillis et al., 1995Gillis D. Klaus S. Schnur L.F. Piscopos P. Maayan S. Okon E. Engelhard D. Diffusely disseminated cutaneous Leishmania major infection in a child with acquired immunodeficiency syndrome.Pediatr Infect Dis J. 1995; 14: 247-249Crossref PubMed Scopus (42) Google Scholar;Coutinho et al., 1996Coutinho S.G. Da-Cruz A.M. de Oliveira M.P. Mendonca S.C. De Bertho A.L. Luca P. CD4+ and CD8+ T cell immune responses of immunocompetent and immunocompromised (AIDS) patients with American tegumentary leishmaniasis.Mem Inst Oswaldo Cruz. 1996; 91: 381-384Crossref PubMed Scopus (12) Google Scholar;Kubar et al., 1998Kubar J. Marty P. Lelievre A. Quaranta J.F. Staccini P. Caroli-Bosc C. LeFicoux Y. Visceral leishmaniosis in HIV-positive patients: primary infection, reactivation and latent infection. Impact of CD4+ T-lymphocyte counts.AIDS. 1998; 12: 2147-2153Crossref PubMed Scopus (86) Google Scholar;Mattos et al., 1998Mattos M. Caiza A. Fernandes O. Goncalves A.J. Pirmez C. Souza C.S. Oliveira-Neto M.P. American cutaneous leishmaniasis associated with HIV infection: report of four cases.J Eur Acad Dermatol Venereol. 1998; 10: 218-225Crossref PubMed Google Scholar;Castellano et al., 1999Castellano V.M. Rodriguez-Peralto J.L. Alonso S. Gomez-De la Fuente E. Ibarrola C. Dermatofibroma parasitized by Leishmania in HIV infection: a new morphologic expression of dermal Kala Azar in an immunodepressed patient.J Cutan Pathol. 1999; 26: 516-519Crossref PubMed Scopus (20) Google Scholar;Lachaud et al., 2000Lachaud L. Dereure J. Chabbert E. et al.using patient blood samples for diagnosis and follow-up of visceral Leishmaniasis, with special reference to AIDS patients.J Clin Microbiol. 2000; 38: 236-240PubMed Google Scholar;Santos-Gomes et al., 2000Santos-Gomes G. Gomes-Pereira S. Campino L. Araujo M.D. Abranches P. Performance of immunoblotting in diagnosis of visceral Leishmaniasis in human immunodeficiency virus-Leishmania sp.-coinfected patients.J Clin Microbiol. 2000; 38: 175-178PubMed Google Scholar). Although leishmaniasis has been reported in other immunodepressed states, such as diabetes (Figure 3), PKDL in renal transplant recipients, or in those taking corticosteroids, the greater magnitude of the former problem compels us to focus our discussion on concomitant Leishmania and HIV infections (Alrajhi et al., 1998Alrajhi A.A. Saleem M. Ibrahim E.A. Gramiccia M. Leishmaniasis of the tongue in a renal transplant recipient.Clin Infect Dis. 1998; 27: 1332-1333Crossref PubMed Google Scholar;Roustan et al., 1998Roustan G. Jiminez J.A. Gutierrez-Solar B. Gallego J.L. Alvar J. Patron M. Post-kala-azar dermal leishmaniasis with mucosal involvement in a kidney transplant recipient: treatment with liposomal amphotericin B.Br J Dermatol. 1998; 138: 526-528Crossref PubMed Scopus (40) Google Scholar). Co- infection is most frequently manifested as VL (WHO, 2000WHO Leishmania/HIV Co-Infection in Southwestern Europe 1990–98: Retrospective Analysis of 965 Cases. 2000Google Scholar). The increased appearance of leishmaniasis in developed countries can be attributed to several factors: increased overseas