The American leishmaniases: some observations on their ecology and epidemiology

Deforestation: effects on vector-borne disease

This review addresses changes in the ecology of vectors and epidemiology of vector-borne diseases which result from deforestation. Selected examples are considered from viral and parasitic infections (arboviruses, malaria, the leishmaniases, filariases, Chagas Disease and schistosomiasis) where disease patterns have been directly or indirectly influenced by loss of natural tropical forests. A wide range of activities have resulted in deforestation. These include colonisation and settlement, transmigrant programmes, logging, agricultural activities to provide for cash crops, mining, hydropower development and fuelwood collection. Each activity influences the prevalence, incidence and distribution of vector-borne disease. Three main regions are considered--South America, West & Central Africa and South-East Asia. In each, documented changes in vector ecology and behaviour and disease pattern have occurred. Such changes result from human activity at the forest interface and within the forest. They include both deforestation and reafforestation programmes. Deforestation, or activities associated with it, have produced new habitats for Anopheles darlingi mosquitoes and have caused malaria epidemics in South America. The different species complexes in South-East Asia (A. dirus, A. minimus, A. balabacensis) have been affected in different ways by forest clearance with different impacts on malaria incidence. The ability of zoophilic vectors to adapt to human blood as an alternative source of food and to become associated with human dwellings (peridomestic behaviour) have influenced the distribution of the leishmaniases in South America. Certain species of sandflies (Lutzomyia intermedia, Lu. longipalpis, Lu. whitmani), which were originally zoophilic and sylvatic, have adapted to feeding on humans in peridomestic and even periurban situations. The changes in behaviour of reservoir hosts and the ability of pathogens to adapt to new reservoir hosts in the newly-created habitats also influence the patterns of disease. In anthroponotic infections, such as Plasmodium, Onchocerca and Wuchereria, changes in disease patterns and vector ecology may be more difficult to detect. Detailed knowledge of vector species and species complexes is needed in relation to changing climate associated with deforestation. The distributions of the Anopheles gambiae and Simulium damnosum species complexes in West Africa are examples. There have been detailed longitudinal studies of Anopheles gambiae populations in different ecological zones of West Africa. Studies on Simulium damnosum cytoforms (using chromosome identification methods) in the Onchocerciasis Control Programme were necessary to detect changes in distribution of species in relation to changed habitats. These examples underline the need for studies on the taxonomy of medically-important insects in parallel with long-term observations on changing habitats.(ABSTRACT TRUNCATED AT 400 WORDS)

Niche breadth in parasites: an evolutionarily stable strategy model, with special reference to the protozoan parasite Leishmania

A parasite's host range essentially defines its niche breadth, which, as foraging theory predicts, is influenced by resource availability. For parasites, the interaction of infection and transmission characteristics with host population dynamics determines host availability. An epidemiological model, involving two host types and describing competition between a "generalist" parasite strain and a related "specialist" strain, is used to examine the interplay among host range, relative host availabilities, and adaptational compromises engendered by increased host range. Results show that the generalist can predominate even when it cannot maintain itself in either host alone, but that the specialist can persist if its reproductive rate attains some threshold relative to either of the generalist's respective rates in its two hosts. The model is in rough, qualitative agreement with observed dynamics of two Leishmania parasite-host systems, and overall results suggest that infection of two species with a common parasite can lead to complex, indirect coevolutionary dynamics.

Leishmaniasis in the Caribbean Islands. A review

A review is presented of the current knowledge relating to leishmaniasis in the West Indies. The only country where an autochthonous focus of cutaneous leishmaniasis has been discovered within the last 20 years is the Dominican Republic. Most of the cases are of the diffuse clinical type, which tend to be anergic to the Montenegro skin test, but subclinical or mild cases are apparently common. The responsible agent is a new species of Leishmania and the suspected vector is Lutzomyia cristophei, the only anthropophilic sandfly on the island; the black rat could be a wild reservoir for the parasite. Sporadic indigenous cases have also been reported in Martinique and in Trinidad. On the latter island, no new cases have been found in the last 60 years, and only an enzootic cycle between rodents and marsupials and Lu. flaviscutellata exists there at present; the responsible parasite in this cycle is L. amazonensis or a closely related species. An apparently indigenous case of visceral leishmaniasis has been reported in Guadeloupe but new studies are needed to confirm if this form of the disease is endemic on the island. The sandfly fauna in some of the larger islands is discussed in relation to the existence of possible vectors and the establishment of the disease. In the case of Haiti, there is no reason for human leishmaniasis not to be present as it is in the neighboring Dominican Republic. In Trinidad, the conditions are present for leishmaniasis to become a true zoonosis at any time, produced by L. amazonensis. In Cuba, conditions seem to be favorable for the introduction of cutaneous leishmaniasis in the near future. No predictions can be made at this time for other islands because of lack of information about the existence of the factors required.

Leishmaniasis epidemiology: the theory catches up

Until recently, almost all studies of leishmaniasis epidemiology were qualitative and descriptive. But now that the natural history of many Leishmania parasites is quite well known, there is growing interest in quantitative analysis. In this paper I use mathematical models in conjunction with field data to try to answer a wider range of questions than has previously been possible with descriptive techniques, and to sharpen some of the outstanding questions for laboratory workers. This is done with reference to the persistence and resilience of canine leishmaniasis, the maintenance of virulence polymorphisms in Leishmania populations, and the possible existence of cycles of human kala-azar. I conclude by posing a set of problems under three headings: diagnosis of infection (as distinct from disease), natural immunity to Leishmania infection in the vertebrate host, and genetic variation in the parasite population. Some solutions from the laboratory can be found in the companion paper by Blackwell (1992).

Cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis in Amazonian Brazil, and the significance of a negative Montenegro skin-test in human infections

The clinical and epidemiological features of 62 cases of cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis, from Pará State, Amazonian Brazil, are discussed. The parasite, isolated in hamster skin and/or blood-agar culture medium, was in each case identified by both biological characteristics and a monoclonal antibody specific for promastigotes of L. (L.) amazonensis. Of the 62 patients, 46 (74.2%) presented with a single cutaneous lesion, and on no occasion was evidence found indicating metastatic spread to either the naso-pharyngeal mucosae or the viscera. Recent claims that this parasite may be responsible for both mucocutaneous leishmaniasis and typical visceral leishmaniasis are discussed. Meglumine antimoniate (Glucantime) proved highly efficient in the treatment of all patients. Of the 62 patients examined by the Montenegro skin test, only 32 (51.6%) gave a positive reaction. The significance of this finding is considered and the hypothesis made that the parasite itself may induce an immunoinhibition. Field studies amply confirmed the role of Lutzomyia flaviscutellata as the major sandfly vector of L. (L.) amazonensis in Amazonia.

The molecular epidemiology of parasites

The explosion of new techniques, made available by the rapid advance in molecular biology, has provided a battery of novel approaches and technology which can be applied to more practical issues such as the epidemiology of parasites. In this review, we discuss the ways in which this new field of molecular epidemiology has contributed to and corroborated our existing knowledge of parasite epidemiology. Similar epidemiological questions can be asked about many different types of parasites and, using detailed examples such as the African trypanosomes and the Leishmania parasites, we discuss the techniques and the methodologies that have been or could be employed to solve many of these epidemiological problems.

[Cutaneous leishmaniasis in Amazonia: isolation of Leishmania (Viannia) lainsoni from the rodent Agouti paca (Rodentia: Dasyproctidae), in the state of Pará, Brazil]

The isolation of Leishmania (V.) lainsoni is recorded for the first time from a wild animal, the rodent Agouti paca (Rodentia: Dasyproctidae), from Pará State, north Brazil. Isolates of the parasite were made from apparently normal skin of 3 specimens of this rodent captured on the Island of Tocantins, in the municipality of Tucuruí, an area subsequently flooded in the formation of the lake associated with the Tucuruí hydroelectric dam. No isolations were made from the viscera. Identification of the parasite was in each case based on morphology of the amastigotes and promastigotes, behavior of the organism in hamsters, isoenzymes profiles and the use of monoclonal antibodies. The inapparent nature of the infection leads us to suggest that the "paca", Agouti paca, represents a primitive host of L. (V.) lainsoni in the Amazon Region.

Molecular cloning and characterization of the immunologically protective surface glycoprotein GP46/M-2 of Leishmania amazonensis

Immunization of mice with the GP46/M-2 membrane glycoprotein has been demonstrated to elicit protection against infection with the parasitic protozoan Leishmania amazonensis. As this molecule is important for future vaccine studies of leishmaniasis, the gene encoding the GP46/M-2 surface membrane glycoprotein of Leishmania amazonensis has been cloned and sequenced. The protein sequence derived from the DNA sequence data is consistent with the known biochemical and immunochemical properties of the protein and indicates a number of structural areas of interest. A repetitive sequence (24 amino acids repeated four times) occurs within the amino-terminal portion of the molecule and constitutes approximately 22% of the total mature protein. The protease-resistant immunodominant carboxyl-terminal domain of the protein comprises approximately half of the molecule and consists of proline-rich and cysteine-rich areas of sequence; the distribution of cysteine residues is suggestive of metal binding motifs. The sequence predicts a hydrophobic leader peptide, and a putative attachment site for a glycosyl-phosphatidylinositol anchor is indicated at the carboxyl terminus, consistent with the membrane location of the protein. Southern blot analyses also indicate the presence of a GP46/M-2 gene family.

Antigenic differences of Leishmania amazonensis isolates causing diffuse cutaneous leishmaniasis

Six geographically distinct isolates of Leishmania amazonensis causing diffuse cutaneous leishmaniasis (DCL) (from Bahia and Maranhão, in Brazil and Guarico, in Venezuela) were characterized by immunoblot analysis to see whether any geographical or strain-related differences existed in antigenic composition. Western blots of promastigote homogenates were reacted with polyclonal sera from patients infected with L. amazonensis with the various forms of clinical disease. The pattern of antigenic reactivity of these strains revealed the presence of shared antigenic components between geographically distinct L. amazonensis isolates causing DCL, when tested with the sera of the infected patients. In certain cases, however, some polyclonal sera also detected antigenic fractions unique to the strains examined. Variation was observed between the antigenic components of some isolates of L. amazonensis that were recognized by a single serum, and between the antigenic components of a single isolate of L. amazonensis that were recognized by the different patients' sera. However, no constant association was found between the antigenic components identified in these isolates and the geographical area of isolation. These results indicate that, although these parasites appear to be closely related antigenically, they also possess some strain-related antigenic differences.

Evolution of nuclear DNA and the occurrence of sequences related to new small chromosomal DNAs in the trypanosomatid genus Endotrypanum

Comparisons of nuclear DNA restriction fragment patterns were used to examine the evolutionary relatedness among 17 strains previously identified as Endotrypanum, a trypanosomatid parasite of sloths. Fragments were obtained with 6 restriction enzymes and analyzed by Southern blotting with hybridization probes from three loci. An estimate of the percent nucleotide sequence divergence among strains, delta, was calculated and used to construct molecular evolutionary trees. The 17 isolates fell into four distinct groups, one of which (group D) showed no more relationship to groups A-C than it did to other genera (Leishmania, Crithidia, Leptomonas, Trypanosoma), being too distant to be resolved with this method. These and other data suggest that group D may not actually be Endotrypanum. Molecular karyotype analysis revealed considerable variation among the chromosomes of these strains. One strain (LV88, group B) contained a linear 70-kb chromosome not evident in other isolates. Hybridization probes specific for this chromosome (LV88-70) were developed and revealed that related sequences were present at high levels in group B isolates and low levels in group A isolates, although a complex hybridization pattern was evident. Sequences related to LV88-70 were not present in groups C and D, nor in Leishmania major, showing that this DNA has a disjunct distribution which curiously parallels that of virus-like particles present in these isolates.

Quantitative study of Leishmania braziliensis braziliensis reactive T cells in peripheral blood and in the lesions of patients with American mucocutaneous leishmaniasis

A limiting dilution analysis (LDA) was utilized to estimate the frequency of L. braziliensis braziliensis reactive T cells (Lbb-T cells) in peripheral blood and in the lesions of patients with mild localized cutaneous leishmaniasis (LCL) or with severe mucosal leishmaniasis (MCL). The frequencies of Lbb-T cells in peripheral blood varied from 1:107300 to 1:3587 and were not significantly different in MCL and LCL patients. However, a significant difference was encountered (P less than 0.02) between the T cells frequencies in cutaneous (1:748 to 1:45) and mucosal lesions (1:152 to 1:13). A positive correlation was also observed between these frequencies and the magnitude of delayed-type hypersensitivity (DTH) (P less than 0.01) and the presence of fibrinoid necrosis and granulomatous reaction in the site of the lesions (P less than 0.05). The lack of correlation between the severity of disease (MCL or LCL) and the frequency of Lbb-T cells in peripheral blood gave no indications towards understanding the physiopathology of severe or mild disease. However, the correlation between high T cell frequencies in the site of the lesions, the magnitude of DTH, the fibrinoid necrosis and the severity of the disease (MCL lesions) points to the possibility that the presence of a strong T cell dependent cellular immune response in the site of the lesions may have a deleterious effect. However, a local well modulated T cell immune response might provide healing of the lesions.

Monoclonal antibodies specific for members of the genus Endotrypanum

Twenty-six monoclonal antibodies were produced against membrane-enriched preparations of Endotrypanum schaudinni or Endotrypanum sp. promastigotes. Fifteen of these monoclonal antibodies (E1-E15) reacted only with the standard strain of E. schaudinni, M6159. Monoclonal antibodies E16-E26 were considered Endotrypanum specific; no cross reactivity was detected with any other genus of the family Trypanosomatidae (Leishmania, Trypanosoma, Leptomonas, Herpetomonas or Crithidia) by dot-blot radioimmune assay. By indirect immunofluorescence assay, the antigens recognized by Endotrypanum specific monoclonal antibodies appear to be associated with the surface of the parasite. Based on Western blot analysis, 4 antigenic molecules ranging in molecular weight from 24 kD to 160 kD were identified by monoclonal antibodies specific for the strain of E. schaudinni, M6159. Monoclonal antibodies specific for the genus Endotrypanum identified an antigen of molecular weight 48 kD as well as a diffuse component migrating with an apparent molecular weight of 64-200 kD.

Membrane glycoprotein M-2 protects against Leishmania amazonensis infection

Previous passive antibody transfer experiments have indicated that immunity to a 46-kilodalton membrane glycoprotein (M-2) of Leishmania amazonensis may protect against infection with this parasite. In the studies described in this paper, we investigated the ability of the purified M-2 molecule to elicit a protective immune response in conjunction with Freund incomplete and complete adjuvants, saponin, and Corynebacterium parvum. Both relatively susceptible (BALB/c and CBA) and resistant (C57BL/6) strains of mice were examined. C. parvum appeared to be the most effective adjuvant in the three mouse strains tested. The level of protection varied with the mouse strain, although all animals received identical preparations of antigen and adjuvant. Immunization of CBA mice with the M-2 glycoprotein and C. parvum resulted in complete protection against a challenge infection of 10(4) and 10(6) late log-phase promastigotes of L. amazonensis. In the BALB/c strain, complete protection was observed in some of the immunized animals (28 to 50%); in the rest of the mice the onset of infection was significantly delayed. Protective immunity for C57BL/6 mice was observed only at the low infecting dose (10(4) L. amazonensis organisms). The level of protection observed is reflected by increased antibody response (immunoglobulins G1 and G2) developed to the M-2 molecule. The relationship of pure T-cell (nonantibody) immunity to this protection remains to be elucidated.

Ecological interactions in the transmission of the leishmaniases

Epidemiological studies on the leishmaniases are disclosing a multiplicity of Leishmania species infecting a wide range of wild mammalian hosts, from marsupials to monkeys. In the primitive, silvatic habitat these parasites are transmitted by an equally wide variety of phlebotomine sandfly species (Diptera: Psychodidae: Phlebotominae). Transmission is not haphazard, however, and available evidence points to the existence of environmental barriers that normally limit the different Leishmania species to specific sandfly vectors, transmitting to certain mammalian species, within distinct ecotopes. In this situation, humans may become infected by a variety of leishmanial parasites when intruding into the different enzootics, if the sandfly vectors are anthropophilic. Many are not, however, and their parasites rarely, if ever, make contact with the human host. Natural or man-made ecological changes may result in modification of the epidemiological pattern of leishmaniasis, leading to either a reduction or an increase in the human disease.

American cutaneous leishmaniasis: presentation and problems of patient management

We report our experience with the diagnosis and treatment of 60 patients with American cutaneous leishmaniasis. They were infected in Panama (55), Brazil (4) or Colombia (I). Among 35 patients with a 3 week exposure in Panama, the mean maximum incubation period was 33 days (range 4-81 days). Diagnosis was delayed an average of 93 days after onset of skin lesions, due to the patient's delay in seeking medical attention (31 days), medical personnel's delay in considering the diagnosis (45 days), and the laboratory's delay in confirming the diagnosis (17 days). Forty-four patients (73%) developed ulcers typical of cutaneous leishmaniasis. Sixteen additional patients (27%) had atypical macular, papular, squamous, verrucous or acneiform skin lesions that were diagnosed only because leishmanial cultures were obtained. Of the 59 patients treated with pentavalent antimonial drugs, only 34 (58%) were cured after the first course of treatment. Lesions which were at least 2 cm in diameter, ulcerated, or caused by Leishmania braziliensis were less likely to be cured after a single course of treatment than were lesions smaller than 2 cm, nonulcerated or caused by Leishmania mexicana or Leishmania donovani.

The status of Leishmania tarentolae/Trypanosoma platydactyli

Taxonomic studies and classification of Leishmania species have developed rapidly in recent years, but controversy still surrounds the relationships between those species infecting lizards and those infecting mammals. Some authorities maintain that the leishmanias o f lizards form a sufficiently distinct group to be ranked as a separate genus - Sauroleishmania(1,2) - while Wallbanks et al. have gone further to suggest that such species might be classified within the genus Trypanosoma(3). This suggestion followed from work showing that promostigote forms of Trypanosoma platydactyli from a gecko, had similar isoenzyme profiles to Leishmania tarentolae, a well-known species from lizards. In this article however, Larry Simpson and George Holz Jr discuss conflicting evidence, concluding from recent studies of DNA and lipid composition that the lizard leishmanias are more closely related to mammalian leishmanias than to trypanosomes.0.

Sporotrichoid leishmaniasis in patients from Saudi Arabia: clinical and histologic features

The clinical and pathologic presentations of cutaneous leishmaniasis in the various countries of the Middle East are well documented. The defined patterns currently encountered in the region emphasize the rarity of local extension of the infection from the bite site. Between 1970 and 1980 we have seen 24 patients with cutaneous leishmaniasis who acquired the infection in Saudi Arabia. In these patients there were several interesting variations from the hitherto described patterns of Oriental sore. The variations include, clinically, the appearance of satellite lesions and the presence of sporotrichoid spread of infection; and histologically, the presence of stellate intradermal abscesses. Such variations in the clinical and pathologic presentations may be due to differences either in the host's immunologic reactivity or in the Leishmania organisms found in Saudi Arabia. Speculative evidence supports the possibility of a different strain and/or species of Leishmania tropica in Saudi Arabia, which in turn may be responsible for this unique clinicopathologic presentation.

Histological and immunohistochemical aspects of cutaneous leishmaniasis in Nicaragua

Sixty skin biopsies of fifty-eight non-treated patients with cutaneous leishmaniasis from Nicaragua were studied. Biopsies were classified according to Ridley's histopathologic groups: 36 (60%) were included in group B (diffuse necrosis), 14 in group C (focal necrosis), 7 (11.6%) in group D (reactive tuberculoid). Only three biopsies remained unclassified. None of our cases could be included in groups A and E. Immunohistochemistry disclosed in 17 cases Russel's bodies secreting IgM and only one IgG positive. There was no correlation between the histopathologic groups and the presence of Russel's bodies. However, we believe the presence of Russel's bodies help the diagnosis of leishmaniasis. Correlation between morphological patterns and the different leishmania species was also considered.

American Leishmania spp: formycin B treatment of cutaneous leishmaniasis in mice

Using foot-pad infection of female C57BL/6, DBA/2J and NMRI-IVIC mice as an animal model for American cutaneous leishmaniasis (ACL), we evaluated the inhibitory effect of Formycin B (FoB) on the infection produced by 7 different Leishmania isolates. When treatment was initiated some days, or even some weeks, after infection a significant leishmanistatic effect was detected on mice infected with all Leishmania isolates, which reached 30-55 weeks for some isolates. The optimal dose schedule was 1.25 mg/kg body weight/day, injected intraperitoneally for 20 consecutive days. Significant differences in the sensitivity of various Leishmania spp. to FoB were found, either in vivo, or in vitro where a high [3H]FoB incorporation rate was found only for certain Leishmania isolates. The low toxicity of this drug and the sensitivity of the 7 Leishmania isolates tested suggest that FoB could be useful in the treatment of ACL.

Characterization of Leishmania species from Peru

Twenty-six isolates of Leishmania parasites of Peruvian origin were studied by isoenzyme electrophoresis of four marker enzymes (ASAT, ALAT, G6PD and GPI), kinetoplast DNA hybridization and monoclonal antibody binding and compared with marker strains of the New World organisms L. b. braziliensis, L. b. guyanensis, L. m. mexicana and L. m. amazonensis. 12 of the isolates studied were of Andean origin; 11 of these were isolated from patients with Andean cutaneous leishmaniasis. The organisms originating from the Peruvian Amazonian forest were isolated from patients with cutaneous (12 cases) or mucocutaneous (2 cases) leishmaniasis. One of the Andean isolates was obtained from an infected phlebotomine vector. 25 of the new isolates were identified as L. braziliensis ssp. according to the three techniques employed. The results of monoclonal antibody binding showed that 23 of the isolates were indistinguishable from L. b. braziliensis. Two isolates identified as L. braziliensis ssp. according to their isoenzyme profiles and k-DNA hybridization patterns could not be classified at the subspecies level. The isolate obtained from the phlebotomine vector could not be identified. No evidence of the existence of parasites of the L. mexicana complex in Peruvian territory was found in this study. The results obtained show a remarkable similarity between Leishmania of Andean origin and L. b. braziliensis.

Leishmaniasis in Brazil. XXIV. Natural flagellate infections of sandflies (Diptera: Psychodidae) in Pará State, with particular reference to the rôle of Psychodopygus wellcomei as the vector of Leishmania braziliensis braziliensis in the Serra dos Carajás

Between July 1983 and December 1984 natural flagellate infections were found in 114 (1%) of 11,586 female phlebotomine sandflies (Diptera: Psychodidae) of 21 species. A further 1084 females of 17 other species were not infected. Identification of the organisms on a number of occasions confirms the exclusive parasite/vector relationship of Leishmania mexicana amazonensis/Lutzomyia flaviscutellata and Le. braziliensis braziliensis/Psychodopygus "wellcomei". Undescribed or unidentified Leishmania spp. were isolated from Lu. shawi, Lu. ubiquitalis, Lu. whitmani, Ps. hirsutus, Ps. paraensis Ps. "wellcomei", and trypanosomes from Lu. nordestina and Lu. trinidadensis. Flagellate infections were recorded in 8 of 21 species examined for the first time, and some were isolated directly from insects into cultures. Le. b. braziliensis was transmitted to a hamster by the bite of a wild-caught, naturally infected Ps. "wellcomei". 7 of the 35 infected Ps. "wellcomei" were allowed to oviposit and the eggs were reared to adults. Four produced Ps. wellcomei males only, confirming the rôle of this species as the major vector of Le. b. braziliensis.

Leishmaniasis and malaria: new tools for epidemiologic analysis

Parasitic diseases are still prevalent in many parts of the world, causing both human suffering and economic loss. Recent developments in biotechnology, such as the use of monoclonal antibodies and recombinant DNA, have the potential for providing both more extensive and detailed information on the parasite in the infected human and in insect vectors. New methods of detection, both in man and insect vectors, have been developed for two parasitic diseases, leishmaniasis and malaria. These new methodologies will be important in epidemiologic studies on the prevalence and transmission of these parasitic diseases.

Leishmania braziliensis: development of primary and satellite lesions in the experimentally infected owl monkey, Aotus trivirgatus

Twelve male and 8 female feral owl monkeys, Aotus trivirgatus, were inoculated intradermally at the dorsal base of the tail with 2 X 10(7) promastigotes (strains WR 128 or WR 539) or 5 X 10(5) amastigotes (strain WR 128) of Leishmania braziliensis panamensis, and the progression and regression of subsequent lesions were examined for up to 13 or 54 weeks after inoculation. Three of these monkeys had been infected previously with L. donovani, had been treated with meglumine antimoniate, and had recovered clinically from visceral leishmaniasis. All monkeys developed a cutaneous nodule at the inoculation site, but the size of the nodule varied (maximum 78 to 326 mm2 between 4 and 16 weeks after inoculation.) The initial nodule became ulcerated after 4 to 8 weeks in 17 of the 20 monkeys, and the ulcers persisted for 4 to 16 weeks until covered by a crust. Primary lesions disappeared by 17 to 52 weeks after inoculation, but satellite lesions, of similar morphology to the primary lesions but smaller, developed after 4 to 21 weeks in 14 of the monkeys. The primary nodule was excised in 4 monkeys at 6 weeks and did not recur nor did satellite lesions subsequently develop. The satellite lesions (median total number of 4, range 1 to 25) were adjacent to or at a maximum distance of 6 cm from the primary lesion, varied in size from 3 to 117 mm2, and persisted for 10 to 37 weeks. At 6 and 8 weeks after inoculation, tissue from the cutaneous leishmanial lesions from five monkeys was excised and examined. The granulomatous leishmanial lesions, located primarily in the dermis and subcutis, consisted of macrophages containing parasites, lymphocytes, plasma cells, and occasionally eosinophils. Satellite lesions at 14 weeks after inoculation were similar grossly and microscopically to the initial nodule. No significant differences were observed between promastigote or amastigote derived infections, between the two strains of L. b. panamensis, or between the course of infection based on the sex, age, karyotype, or country of origin of the owl monkeys. Cutaneous lesions developed when 5 X 10(5) amastigotes of L. b. panamensis (strain WR 128) were inoculated intradermally into the dorsal base of the tail, the upper eyelid, and the thorax of three monkeys. Leishmanial nodules which developed on the thorax regressed rapidly (after 2 to 5 weeks) whereas those on the upper eyelid and at the dorsal base of the tail persisted for 5 to 45 weeks after inoculation.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection and characterization of Leishmania species and strains from mammals and vectors by hybridization and restriction endonuclease digestion of kinetoplast DNA

Leishmania parasites from animals, man or insect vectors were characterized by the gel electrophoresis of restriction endonuclease enzyme-produced mitochondrial (kinetoplast) DNA (kDNA) fragments and/or by DNA-DNA hybridization with 32P-labelled cloned, or uncloned, kDNA fragment probes from type isolates. The electrophoretic separation of kDNA fragments is a sensitive method for detecting genetic similarities and differences among Leishmania. Parasites with similar kDNA restriction fragment patterns belong to the same schizodeme and schizodeme analysis is useful for studying Leishmania populations. Cloned, species-specific kDNA probes detected Leishmania in sandflies and in liver, spleen or blood preparations from infected animals. Cloned DNA probes also hybridized to immobilized kDNA from in vitro cultivated promastigotes and detected as few as 100 parasites in a species-specific manner. Sensitive DNA hybridization probes should be useful in research on the immunology, chemotherapy or epidemiology of animal and human leishmaniasis.

IgE antibody against surface antigens of Leishmania promastigotes in American cutaneous leishmaniasis

As IgE-mediated immune mechanisms participate in the host defence against some types of parasites, we evaluated sera from American cutaneous leishmaniasis (ACL) patients for the presence of this antibody against Leishmania. Using monoclonal antibodies against human IgE and an immunoperoxidase staining technique, 48% of the patients sera tested were found to contain IgE antibody that bound strongly to Leishmania promastigotes. A much lower proportion of sera from non-symptomatic subjects from either endemic or non-endemic areas of the disease contained significant levels of anti-Leishmania IgE antibody (6.5% and 0% respectively). The results indicated that the IgE antibody bound predominantly to surface components of the promastigotes, and reactivity against the intracellular amastigote form of the parasite was rarely detected. Somewhat unexpectedly, in a small proportion of the sera, the IgE antibody showed apparent specificity for L. mexicana or L. braziliensis. This study demonstrates that ACL patients can develop anti-Leishmania IgE antibody responses, that seem to be directed preferentially against surface antigens of promastigotes, and that can be strain specific. This raises the question as to the possible contribution of this antibody to the immune defence mechanisms against the parasite.

Leishmania in the Old World: 2. Heterogeneity among L. tropica zymodemes

Isoenzyme profiles of 27 stocks of Leishmania tropica from widely separated geographical areas were compared with those of reference strains of L. tropica and L. major using starch-gel electrophoresis of 13 enzymes (GPI, GD, ES, PGM, PEPD, NH, ASAT, ALAT, PK, MPI, 6PGD, SOD, MDH). 18 zymodemes were seen. L. tropica showed considerable intraspecific variation which did not correlate with its epidemiological uniformity. Isolates from cases of cutaneous and visceral leishmaniasis and leishmaniasis recidivans were identified as L. tropica. Only one isoenzyme band was held in common with the enzyme profile of the L. major reference strain thus supporting the status of L. tropica as a separate species.

In situ detection of amastigotes in American cutaneous leishmaniasis, using monoclonal antibodies

Using an immunoperoxidase technique we have applied monoclonal antibodies against American Leishmania for the detection of amastigotes in biopsies from cutaneous leishmaniasis patients. The immunocytochemical procedure was notably superior to conventional histological staining in terms of the visualization and definition of the amastigotes. This technique could eventually prove to be of value in epidemiological studies, and possibly have prognostic importance, by allowing the in situ characterization of the species of infecting organism.

Clinical aspects of cutaneous leishmaniasis acquired in Texas

Five patients with cutaneous leishmaniasis are described. Four of these patients acquired leishmaniasis in Texas. Four cases represent acute cutaneous leishmaniasis, and one case probably represents chronic cutaneous leishmaniasis. The classification and treatment of cutaneous leishmaniasis are reviewed. One patient in this report was successfully treated with topical antimony cream. Cutaneous leishmaniasis must be considered in the differential diagnosis of nonhealing ulcerated papules and nodules even in patients who do not have a foreign travel history.

A comparison of selected immunological techniques used to detect anti-leishmanial antibodies in the sera of two reptile species

European green lizards (Lacerta viridis) and spiny-tailed agamids (Agama caudospinosum) were obtained from areas endemic for human leishmaniasis. Serum antibody titres against Leishmania agamae, a reptilian leishmanial species, in normal lizards and lizards injected with Leishmania agamae promastigotes were measured by 5 immunological methods commonly used in the serodiagnosis of the human and mammalian leishmaniasis viz. immobilisation test (IMM), direct agglutination (DA), complement-fixation test (CFT), indirect haemagglutination (IHA) and enzyme-linked immunosorbent assay (ELISA). Correlation coefficients (r) were determined for comparisons between each method and linear regression equations calculated to convert antibody titres by one method to those by another. In each lizard species, the IMM test gave the lowest values while the highest were obtained with ELISA. The highest mean titre obtained by ELISA was between 2 and 10 times that obtained by the other methods for both control and immune sera. The methods of preparing the leishmanial antigen extracts affected the IHA and ELISA titres, while the source of complement was critical in obtaining good CFT values. Correlations ranging from 3% to 77% were found for the control animals but higher values ranging from 65% to 96% were obtained with the immunised lizards. Overall, the best correlation was with IHA and ELISA (r greater than 0.82) and with ELISA values for different antigen preparations compared with each other for both control (r greater than 0.67) and immune (r greater than 0.90) sera. ELISA thus appears the most sensitive method for detection and quantitation of anti-flagellate antibodies in normal lizard serum and for the determination of titres in immune serum. ELISA is the most applicable technique for screening reptiles and other lower vertebrates for anti-parasite immunoglobulins, and for screening potential carriers or reservoirs of infective flagellates in epidemiological studies aimed at disease control, especially in areas where human infections are prevalent.

Human mucocutaneous leishmaniasis in Três Braços, Bahia - Brazil: an area of Leishmania braziliensis braziliensis transmission. II. Cutaneous disease. Presentation and evolution

The clinical records of 182 patients with cutaneous leishmaniasis probably due to Leishmania braziliensis braziliensis are analysed. 68% had a single lesion which was usually an ulceron the lower anterior tibial third. Many had short histories of one to two months and all age groups were represented 13% had closed lesions of a verrucose or plaque like nature. Evolution of these skin lesions after treatment was related to the regularity of antimony therapy. Although healing usually occurred in three months, the time to scarring after commencing treatment was variable and related to the size ofthe lesion (p < 0.01). Usually if sufficient antimony treatment was given the lesion closed. Seven of the ten patients with initially negative leishmanin skin tests converted to positive after treatment. A significant decline of indirect fluorescent antibody titres occurred in patients followed, during and after therapy.

Leishmania mexicana: aspectos taxonómicos y rareza de la infección humana en Três Braços, Bahia, Brasil

Del estúdio de 51 stocks de Leishmania aislados de pacientes humanos de leishmaniasis cutaneomucosa en Três Braços, Bahia, Brasil, los autores describen, en detalle, el análisis de los dos únicos stocks de L. mexicana, identificando uno de ellos como L. mexicana amazonensis. El otro aislado permanece en posición taxonómica no definida pues considerándosele como un miembro de L. mexicana, encuéntranse dificultades para su identificación subespecífica. Evaluan también los parâmetros biológicos e isoenzimáticos y discuten el papel de los anticuerpos monoclonales en la tipificación de éstos stocks. Los autores remarcan la rareza de la transmisión de parásitos del complejo L. mexicana en esta región, aun cuando estudien epidemiológicamente por mais de 8 anos la infección humana.