Leishmaniasis in Brazil. V. Studies on the epidemiology of cutaneous leishmaniasis in Mato Grosso State, and observations on two distinct strains of Leishmania isolated from man and forest animls

Presence of trypanosomatids, with emphasis on Leishmania, in Rodentia and Didelphimorphia mammals of a rural settlement in the central Amazon region

BACKGROUND

Trypanosomatids are widespread and cause diseases - such as trypanosomiasis, sleeping sickness, Chagas disease, and cutaneous and visceral leishmaniasis - in animals and humans. These diseases occur in both rural and urban regions due to unplanned growth and deforestation. Thus, wild and synanthropic reservoir hosts living in residential areas are risk factors.

OBJECTIVE

We aimed to evaluate the diversity of small mammals (rodents and marsupials), and the occurrence of trypanosomatids, especially Leishmania, in the rural settlement of Presidente Figueiredo, Amazonas.

METHODS

Animals were collected using Sherman, Tomahawk, and Pitfall traps along 16 trails in four landscapes: continuous forest, forest with planting, planting, and peridomiciliar. Leishmania sp. was detected in liver samples by polymerase chain reaction targeting kDNA.

FINDINGS

Diversity was higher in forests with planting and lower around residences. In total, 135 mammals (81 rodents and 54 marsupials covering 14 genera) were captured. Rodents presented infection rates (IR) of 74% and marsupials of 48%. Rodents in domicile landscapes presented a higher IR (92.9%), while marsupials showed a higher IR in forests (53.3%).

MAIN CONCLUSIONS

The results suggest high prevalence of trypanosomatids across 12 mammalian genera possibly involved as reservoir hosts in the enzootic transmission of leishmaniasis in the Amazon’s rural, peridomiciliar landscape.

Leishmania in synanthropic rodents (Rattus rattus): new evidence for the urbanization of Leishmania (Leishmania) amazonensis

This study aimed to detect parasites from Leishmania genus, to determine the prevalence of anti-Leishmania spp. antibodies, to identify circulating species of the parasite, and to determine epidemiological variables associated with infection in rats caught in urban area of Londrina, Paraná, Brazil. Animal capture was carried out from May to December 2006, serological and molecular methods were performed. DNA was extracted from total blood, and nested-PCR, targeting SSu rRNA from Leishmania genus, was performed in triplicate. The positive samples were sequenced twice by Sanger method to species determination. In total, 181 rodents were captured, all were identified as Rattus rattus and none showed clinical alterations. Forty-one of the 176 (23.3%) animals were positive for Leishmania by ELISA and 6/181 (3.3%) were positive by IFAT. Nine of 127 tested animals (7.1%) were positive by PCR; seven were identified as L. (L.) amazonensis, one as L. (L.) infantum. Four rats were positive using more than one test. This was the first description of synanthropic rodents naturally infected by L. (L.) amazonensis (in the world) and by L. (L.) infantum (in South Brazil). Regarding L. (L.) amazonensis, this finding provides new evidence of the urbanization of this etiological agent.

Natural infection of Leishmania (Viannia) braziliensis in Mus musculus captured in Mato Grosso, Brazil

We report natural infection by Leishmania (Viannia) braziliensis in Mus musculus and Necromys lasiurus using molecular analyses (PCR-RFLP) of femoral bone marrow and skin fragments. The aim of this study was to detect infection by pathogenic species of Leishmania in small mammals in the state of Mato Grosso, Brazil. The animals were captured in Peixoto de Azevedo, a cutaneous leishmaniasis-endemic region located in the north of the state, from October 30 to November 3, 2008. Natural infection by Leishmania in synanthropic rodents may be a threat to humans due to cohabitation of human domiciles in this area.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

Leishmania (Viannia) braziliensis is the prevalent species infecting patients with tegumentary leishmaniasis from Mato Grosso State, Brazil

The frequency of Leishmania (Viannia) braziliensis infection among patients of Mato Grosso, Brazil was estimated by polymerase chain reaction-PCR, DNA hybridization and by isoenzyme electrophoresis. Analysis of DNA polymorphism was carried out using random amplified polymorphic DNA-PCR (RAPDPCR) with five different primers. The patients were attended from May 1997 to February 1998 at the Reference Ambulatory for American Tegumentary Leishmaniasis at Júlio Müller University Hospital of the Federal University of Mato Grosso, Brazil. In a first screening by PCR and DNA hybridization 94.1% of 68 patients, from whom parasites were isolated in culture medium, were found to be infected with species of the Le. braziliensis complex. Only four patients (5.9%) were infected with species of Le. mexicana complex. Thirty-three samples of Le. braziliensis complex and three of Le. mexicana complex were typed by isoenzyme analysis as Le. (V.) braziliensis sensu stricto and Le. (Leishmania) amazonensis, respectively. The predominant species was Le. (V.) braziliensis, although most of the patients of this study came from the northern area of Mato Grosso, which is part of the Amazonian region of Brazil, where other known species of both subgenus Viannia (Le. braziliensis complex) and Leishmania (Le. mexicana complex) are present. The results of RAPD showed higher genetic variability among the Le. (V.) braziliensis samples from Mato Grosso. The importance of these results concerning the taxonomic status of New World Leishmania, and their implications for both clinical and epidemiological data is discussed.

PCR-based diagnosis for detection of Leishmania in skin and blood of rodents from an endemic area of cutaneous and visceral leishmaniasis in Brazil

The technique of polymerase chain reaction (PCR) associated to hybridization was used to screen 123 samples collected from wild and synanthropic rodents captured in a cutaneous and visceral leishmaniasis endemic area in the State of Minas Gerais, Brazil. The detection of Leishmania spp in naturally infected rodents is of fundamental importance for incriminating them as possible reservoir hosts of the diseases in Minas Gerais. A total of 62 specimens belonging to wild (Thrichomys apereoides, Oryzomys subflavus, Galea spixii, Bolomys lasiurus and Wiedomys pyrrhorhinos) and synanthropic (R. rattus) rodent species were captured in different ecotopes. Blood and skin samples were submitted for PCR analyses followed by molecular hybridization with specific probes for the three Leishmania-species complexes. Fifteen samples were found positive after PCR-hybridization and identified as follows: nine belonging to the L. mexicana complex, three to the L. braziliensis complex and three to the L. donovani complex. Positive PCR results were found in 11 out of the 61 (18%) blood samples and in four out of the 62 (6.4%) skin fragments screened. R. rattus and T. apereoides were the most abundant species in the area also presenting high prevalence of natural infection. The presence of parasite DNA belonging to L. braziliensis, L. mexicana and L. donovani complexes was confirmed in several individuals of a rodent species, R. rattus. This work is the first report of the detection of L. (L.) chagasi in a naturally infected T. apereoides. The utility of filter paper as a substrate for PCR analyses and the efficacy of the procedure associated to the hybridization is emphasized.

Intradermal inoculations of low doses of Leishmania major and Leishmania amazonensis metacyclic promastigotes induce different immunoparasitic processes and status of protection in BALB/c mice

In order to simulate the natural long term parasitisms which may occur in mammals infected with Leishmania, cutaneous leishmaniases due to Leishmania major or Leishmania amazonensis were induced using a model based on the inoculation of 10-1000 metacyclic promastigotes into the ear dermis of BALB/c mice. The final outcome of these parasitisms was dependent upon the number of inoculated parasites. Only some of the mice inoculated with ten parasites displayed cutaneous lesions, whereas most mice infected with 100 metacyclics and all mice infected with 1000 metacyclics developed progressive lesions. We found, using the latter experimental conditions, that the onset of the pathology was associated with: (a) parasite multiplication in the inoculation site and the draining lymph node correlating with an increase of the lymph node cell number, especially in L. major-infected mice; and (b) the detection of lymph node cells, at least in part CD4(+) T lymphocytes, able to produce high levels of interferon-gamma, interleukin (IL)-4, IL-10 and IL-13. Thereafter, mice infected by L. major harboured few parasites in the ear and had a 100-fold reduction in lymph node parasite load between 23 and 40 weeks post-inoculation. In contrast, the parasite loads of L. amazonensis-infected mice remained stable in the ear and increased in nodes during the same period of time. Only L. major-infected mice that exhibited cutaneous lesions in the primary site were resistant to the re-inoculation of 1000 metacyclic promastigotes, whereas all L. amazonensis-primary infected mice remained susceptible to a second homologous challenge. These results are the first to document that a status of resistance to re-infection, referred to concomitant immunity, is coupled to the development of primary progressive lesions in L. major-infected BALB/c mice. Such a protective status is absent in L. amazonensis-infected BALB/c mice.

Wild and synanthropic hosts of Leishmania (Viannia) braziliensis in the endemic cutaneous leishmaniasis locality of Amaraji, Pernambuco State, Brazil

Evidence of Leishmania infection was found in small mammals captured between 1996 and 2000 in the Amaraji region, Pernambuco State, Brazil. The kDNA polymerase chain reaction (PCR), using primers specific for subgenus L. (Viannia), was positive for 43/153 water rats (Nectomys squamipes), 13/81 black rats (Rattus rattus), 15/103 grass mice (Bolomys lasiurus), 1/14 marsh mice (Holochilus scieurus), 2/50 field mice (Akodon arviculoides), 2/12 woolly opossums (Marmosa sp.), and 5/37 common opossums (Didelphis albiventris). This same kDNA PCR was positive for 12/61 dog and 8/58 horse skin samples. In paired PCR tests of 203 small mammals, 18.7% were positive with the kDNA primers and 18.2% with rDNA primers. Amastigotes were seen in 26/460 and L. (V.) braziliensis was isolated from 5 grass mice and 1 black rat. We concluded that small mammals, particularly rodents, are infected with parasites of the subgenus L. (Viannia). The isolation of L. (V.) braziliensis zymodeme IOC/Z74 from 6 rodents and the fact that all the other described L. (Viannia) species that commonly infect humans have never been found in rodents or marsupials leads us to suggest that the positive PCRs indicate infections of L. (V.) braziliensis. The isolation of zymodeme IOC/Z74 from humans reinforces our hypothesis that small, ground-loving mammals, such as rodents are the primary reservoirs of L. (V.) braziliensis.

[A canine survey in a recent focus of cutaneous leishmaniasis in the city of Sabará, the metropolitan area of Belo Horizonte]

In 1992, a dog naturally infected with Leishmania was found in a periurban area of Sabará, state of Minas Gerais, where human cutaneous leishmaniasis had been previously described. The parasite was classified as Leishmania, subgenus Viannia, which L. braziliensis, the main species of parasite present in the southeast Brazil, also belongs. In order to assess the importance of the dog in the transmission cycle of the disease, a canine survey was undertaken. Six hundred thirty-one dogs were examined and the prevalence of seropositive dogs for crude Leishmania amazonensis antigen was 3.2%. The presence of infected people and seropositive dogs either near or in the same house was observed. This fact suggests some transmission in the domiciliary environment, with the dogs being a risk factor for human infection in that periurban area. In the other hand, the low percentage of seropositive dogs points towards a secondary importance of these animals in the transmission of Leishmaniasis in that recent focus of the disease.

[Ecological aspects of American tegumentary leishmaniasis: 8. Evaluation of the enzootic activity of Leishmania (Viannia) braziliensis, in forest and peridomiciliary environments of the Ribeira Valley region, São Paulo State, Brazil]

The evidence of mucocutaneous leishmaniasis transmission in the non-forest environment in the Ribeira Valley region, São Paulo, Brazil, has made this epidemiologic four years' study possible, viewing the enzootic activity of L. (V.) braziliensis. Furthermore, the natural infection in small mammals and the domestic dog population has been completed in collecting of phlebotomine sandflies in the forest and peridomiciliar environments. Positive test-results have only been found in resident dogs (Canis familiaris) with a rate of 5.6 and 2.4% for serological and parasitological test respectively. Among silvatic and synanthropic rodents collected, Oryzomys (Olygoryzomys) and Rattus rattus are pre-eminent having both been collected in equal proportions, in peridomiciliar environment. The sandfly Lutzomyia intermedia has contributed only with 166 feminine specimens due to insecticide (DDT) application on and in the human and domestic habitations. From the general epidemiologic standpoint the fragile L. (V.) braziliensis cycle in the unforested areas as well as the canine and small mammals roles as a domiciliar infection source are discussed, and their potencial in the dispersion of this parasite in the researched area is analysed too.

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.

The use of DNA probes in the identification of leishmanias: discrimination between isolates of the Leishmania mexicana and L. braziliensis complexes

Kinetoplast DNA (kDNA), initially characterized by buoyant density, from ten reference isolates of the Leishmania braziliensis and L. mexicana complexes has been radio-actively labelled and used as hybridization probes. Filters containing endonuclease digested, electrophoresed, Southern transferred fragments of kDNA from reference and other isolates sent to us for DNA typing have been tested for kDNA sequence homology. We record a complete lack of sequence homology between kDNA of any isolate of the L. braziliensis complex and kDNA of any isolate of the L. mexicana complex. L. b. braziliensis, L. b. guyanensis and L. b. panamensis have kDNA sequences in common with each other and with a number of test isolates from Brazil, Panama, Venezuela and Peru. L. b. panamensis (1.695 g/ml) can be separated from L. b. braziliensis or L. b. guyanensis (1.691-1.693 g/ml) by differences in buoyant density of kDNA. L. m. mexicana and L. m. pifanoi have kDNA sequences in common with each other but kDNA of L. m. amazonensis has insignificant homology with kDNA of other reference isolates of the L. mexicana complex. We conclude that the kDNAs of species of the L. mexicana complex are sufficiently different from kDNA of species of the L. braziliensis complex to make kDNA sequence homology identification a feasible proposition.

The American leishmaniases: some observations on their ecology and epidemiology

As the first species of Leishmania encountered were the agents of human visceral and cutaneous leishmaniasis, it is understandable that studies on these parasites for a long time concentrated on those organisms commonly causing disease in man. Epidemiological studies over the past 20 years or so, however, have led to the inescapable conclusion that the genus Leishmania is comprised of numerous species of well adapted parasites, in a wide range of mammals, throughout most of those tropical and subtropical regions of the world where phlebotomine sandflies exist (Diptera: Psychodidae). Many of the leishmanias probably never gain entrance into man: due either to an incapacity to survive in his tissues, or (more likely) because the natural sandfly vectors do not feed on him. The leishmanias that do infect man are, nevertheless, among the greatest protozoological scourges of mankind, and a better understanding of their life-cycles may well help in future prevention or control of the diseases they cause. With few exceptions the leishmaniases are zoonoses, with a major source of infection in wild or domestic animals. In the Americas, the disease is essentially a rural one, and most commonly acquired by those penetrating forested or wooded regions. The following paper deals with the better known human leishmaniases of the New World, and some new ones, and discusses the major historical events in the laborious task of elucidating their ecology and epidemiology.

Leishmaniasis in Brazil: XX. Prevalence of "enzootic rodent leishmaniasis" (Leishmania mexicana amazonensis), and apparent absence of "pian bois" (Le. braziliensis guyanensis), in plantations of introduced tree species and in other non-climax forests in eastern Amazônia

In Amazonian Brazil most human leishmaniasis is due to Leishmania braziliensis s.l. and is acquired during the clearing of primary climax forest. One of the largest deforestation projects has taken place on the JARI property where plantations of exotic tree species are grown for paper pulp. The ability of the regional leishmaniasis enzootics to invade plantations was investigated. CDC light-trap catches indicated the phletobomine vectors of Le. b. guyanensis (causing "pian bois" in man) to be very scarce in JARI plantations compared to native-forest controls. It is concluded (drawing on other observations) that the vectors of "pian bois" are unlikely to thrive in any secondary forest. In contrast, catches from mammal traps and rodent-baited (Disney) traps demonstrated the presence in JARI plantations of infected Proechimys guyannensis and large populations of Lutzomyia flaviscutellata, respectively the major rodent reservoir and sandfly vector of Le. mexicana amazonensis. Alone amongst the local vectors of human cutaneous leishmaniasis, Lu. flaviscutellata is adapted to non-climax forests (primary or secondary, natural or man-made; synopsis given). It is predicted that the public health importance of Le. m. amazonensis is unlikely to diminish following the development of Amazônia. This is worrying because ca. 30% of Le. m. amazonensis infections in man cause highly-disfiguring, incurable "diffuse cutaneous leishmaniasis".

Leishmaniose tegumentar alviericana na Ilha Grande, Rio de Janeiro: III. reservatórios silvestres e comensais

Em 203 animais silvestres e comensais examinados na Praia Vermelha, Ilha Grande, município de Angra dos fíeis, RJ, durante o estudo de um surto de Leishmaniose Tegumentar Americana, foram encontrados 2 exemplares de Proechimys dimidiatus, com lesões hipocrômicas nas extremidades das orelhas, e 1 exemplar de Rattus norvegicus norvegicus, com úlcera de dorso, cuja histopatologia revelou a presença de Leishmania sp. nos 3 exemplares.

Leishmaniose tegumentar americana na Ilha Grande, Rio de Janeiro: IV. reservatórios doméstios

Durante um surto de Leishmaniose Tegumemar Americana (LTA) na Praia Vermelha, Ilha Grande, município de Angra dos Reis, RJ, durante o ano de 1976, os autores examinaram 64 animais domésticos sendo 38 cães e 28 gatos. Nos 38 cães examinados, constatou-se, através de exames histopatolúgicos, infecção natural pela Leishmaniose Tegumentar Americana em 4 (10,52%) cães que apresentavam úlceras com invasão de mucosas localizadas no focinho.

Leishmaniasis in Brazil: XVI. Isolation and identification of Leishmania species from sandflies, wild mammals and man in north Para State, with particular reference to L. braziliensis guyanensis causative agent of "pian-bois"

A total of 125 wild mammals (14 different species) were examined for evidence of infection with Leishmania in an area of primary forest highly endemic for "pian-bois", due to Leishmania braziliensis guyanensis, in north Pará State, Brazil. Parasites isolated were characterized biologically, and biochemically on enzymic profiles. L. b. guyanensis was isolated from the viscera of one lesser anteater (Tamandua tetradactyla) and one opossum (Didelphis marsupialis), and the skin of one rodent (Proechimys guyannensis). The isolates were indistinguishable from 10 others previously made from the sandfly vectors Lutzomyia umbratilis (five) and Lu. whitmani (five), and nine isolates from field-workers who became infected during these studies. Leishmania mexicana amazonensis was obtained from the skin of 21 animals, including three species of opossums (D. marsupialis, Philander opossum and Metachirus nudicaudatus) and two species of rodents (proechimys guyannensis and Dasyprocta sp.). A peripylarian Leishmania isolated from the viscera of two armadillos (Dasypus novemcinctus) was shown to be different, biologically and biochemically, from L. b. guyanensis and L. m. amazonensis. Four other isolates of Leishmania, from the rodents Rhipidomys leucodactylus (one) and P. guyannensis (three) have yet to be characterized owing to their very poor growth in both hamster skin and in vitro culture: they appear closest, however, to L. braziliensis braziliensis. The complexity of Amazonian leishmaniasis is discussed, and attention drawn to the importance of edentates as reservoir hosts of some leishmanias in the New World. Whereas L. mexicana subspecies appear largely restricted to the skin of their natural hosts, subspecies of L. braziliensis are commonly found in the viscera.

Leishmania in phlebotomid sandflies. VII. On the taxonomic status of Leishmania peruviana, causative agent of Peruvian 'uta', as indicated by its development in the sandfly, Lutzomyia longipalpis

The name Leishmania peruviana was given by Velez (1913) to the parasite responsible for a form of cutaneous leishmaniasis known as 'uta'; this disease occurs in the Peruvian Andes. Clinical similarities between uta and 'oriental sore', which is caused by Leishmania tropica of the Eastern Hemisphere, have, however, led to the suggestion that uta is simply due to L. tropica, which was introduced into Latin America by African slaves or European immigrants. Leishmania species are divisible into three distinct sections, according to their pattern of development in their natural (phlebotomine) vectors. One of these sections, the PERIPYLARIA, contains the subspecies of Leishmania braziliensis, and is characterized by parasites that undergo a phase of development attached to the wall of the hindgut (pylorus and ileum), in addition to multiplication in the midgut and subsequent invasion of the foregut. Such development is unknown in any other group of leishmaniae, including those groups of the section SUPRAPYLARIA, which includes parasites of the L. tropica complex. Three isolates of L. peruviana were studied in laboratory-bred sandflies, Lutzomyia longipalpis (Lutz & Neiva), and all showed consistent and prolific development of rounded or stumpy flagellates attached to the wall of the hindgut and, in some instances, growth of free, elongate promastigotes throughout the midgut. Development of both L. tropica and L. major, in the same insect, was restricted to massive development of free flagellates in the midgut, up to the cardial valve. From the behaviour of L. peruviana in the sandfly, its slow growth in hamster skin and the small size of its amastigotes, it is concluded that this parasite is (a) distinctly different from both L. tropica and L. major, and (b) closely related to subspecies of L. braziliensis within the section PERIPYLARIA. On this evidence it is also concluded that L. peruviana is indigenous to the American continent. The specific name is best retained for the time being (rather than L. braziliensis peruviana).

Epidemiology of dermal leishmaniasis in the Rio Doce Valley, State of Minas Gerais, Brazil

Dermal leishmaniasis is prevalent in the predominantly settled agricultural areas in the Rio Doce Valley in the eastern part of the State of Minas Gerais, Brazil. The disease has been recorded almost equally in both sexes. Cases have been confirmed in all age groups but youths aged ten to 14 years form the population segment at greatest risk to infection. Cases of single cutaneous lesions, multiple cutaneous lesions and muco-cutaneous lesions have been recorded in the area. Isolates of parasites include representatives of the Leishmania mexicana and L. braziliensis complexes and at least one parasite that does not fit into either category. Infections have not been detected in small mammals (mainly rodents) but about 3% of dogs are infected. The phlebotomine fauna includes no species (or close relatives of species) previously incriminated as vectors of mexicana and braziliensis infections in Brazil. In the complex and confusing epidemiological situation in the Rio Doce Valley it seems unwise to apply traditional specific names to Leishmania of the area.

Leishmania in phlebotomid sandflies. IV. The transmission of Leishmania mexicana amazonensis to hamsters by the bite of experimentally infected Lutzomyia longipalpis

Leishmania mexicana amazonensis was cyclically transmitted in the laboratory from hamster to hamster by single bites of experimentally infected Lutzomyia longipalpis . The sandflies were denied suitable conditions for oviposition and were induced to take a second, infecting, meal while still gravid. In three transmissions, cutaneous lesions developed rapidly on two hamsters, whereas that on the third remained small for 8 months, almost disappeared, and then grew to the usual large size. In some infected flies, parasites migrated to the pharynx and buccal cavity but then died and disintegrated; in others, healthy parasites were attached to the cuticular intima of the oesophagus and pharynx by hemidesmosomes. The common failure of leishmaniae to become established in the foregut of many experimentally infected sandflies may be because parasites die after migration and not because they fail to migrate. One cause of the death may be a lack of plant juices, a food of sandflies in nature. At the second potentially infecting feed, sandflies usually probed many times and took either no blood or only a small meal. It is suggested that parasites in the foregut block the pores of cibarial sensilla which probably control engorgement; such an interference would be an advantage in the evolution of Leishmania .

[Notes on natural infection of Oryzomys capito laticeps in an euzootic focus of cutaneous leishmaniasis in the Estado de São Paulo, Brazil]

Assinala-se o isolamento de cepa de Leishmania braziliensis braziliensis em exemplar de Oryzomys capito laticeps capturado em foco enzoótico do Estado de São Paulo, Brasil. A identificação do parasita fez-se de acordo com o seu comportamento em inoculação experimental feita em hamsters. Pela primeira vez, relata-se possível papel de reservatório natural, desempenhado por esse roedor, em relação à leishmoniose cutâneo-mucosa.

Infecções naturais de mamíferos silvestres em área endêmica de leishmaniose tegumentar do Estado de São Paulo, Brasil

Descreve-se a presença de foco de leishmaniose tegumentar no vale do rio Moji-Guaçú, em região comum aos municípios de Luiz Antonio, São Carlos, Rincão e Santa Rita do Passa Quatro, no Estado de São Paulo, Brasil. Os casos humanos apresentavam formas clínicas caracterizadas por lesões úlcero-vegetantes, de evolução lenta e pobres em parasitos. As investigações sobre infecção natural em animais silvestres levou ao isolamento de roedores, de três cepas em cultura, duas procedentes de Akodon arviculoides e uma de Oryzomys nigripes. As provas de inoculação em hamsters foram, até o momento, positivas para duas delas, mas com evolução lenta, com manifestações clínicas muito discretas e pobres em parasitos. Pelos dados disponíveis até o momento, parece tratar-se de cepas filiáveis à raça "lenta", à qual se atribui papel na etiologia da forma cutaneo-mucosa da leishmaniose.