Treatment of human head lice infestations in a single application with a new galenic lotion.

To evaluate the efficiency and safety of a new galenic meta-emulsion for the treatment of human head lice (Pediculus capitis) in a single application. A controlled clinical study was conducted comparing lice infestation and nit hatching observed before and after a treatment in a single application. Eighty-two of the 87 children included completed the study. An infestation control was performed on 36 and 46 children, 8 and 24 h respectively after application. Five days later, a meticulous hair examination was carried out to check that the lice infestation was completely cured. After a single application of the lotion being tested, an examination of the scalp with a head lice detection comb, as well as an examination of the rinsing water and the towel used for drying after washing, showed that out of the total 1285 lice, there were no live lice. The percentage of nits hatching before treatment was close to 70%. In comparison, after an 8-h treatment (t(+8)), the percentage of nits hatching was 2.1%, with only 0.35% of living nymphs. After a 24-h treatment (t(+24)), 1.9% hatched with 0.38% living nymphs. Nymphs were revealed to be non-viable. After 5 days (t(+120)), no living adult or immature lice were found on the subjects tested. Moreover, observation of tolerance levels to this treatment at days 1, 5 and 12 showed no side effects. The specific galenic lotion completely cured head lice infestation in the population studied in a single application. The lotion, a patented meta-emulsion, has a mechanical action that asphyxiates lice and nits. Considering the advantages of the single application, the possibility of complete concomitant therapeutics for a whole school population within only 1 day and the high level of tolerance to this treatment, this approach seems simple and promising.

Visceral leishmaniasis in the hoary zorro Dusicyon vetulus: a case of mistaken identity.

The historical identification of the Brazilian 'north-eastern' zorro as Dusicyon vetulus is questioned in relation to its incrimination as a reservoir of Leishmania chagasi, the agent of American visceral leishmaniasis. Comparative cranial and dental morphology showed that specimens of this north-eastern species more closely resemble the crab-eating zorro Cerdocyon thous, conforming with the documented geographical ranges of the respective species. We conclude that the single 'wild' canid host of L. chagasi in the neotropics in C. thous.

Bubonic leishmaniasis: a common manifestation of Leishmania (Viannia) braziliensis infection in Ceara, Brazil.

Enlarged regional lymph nodes have been reported to accompany the cutaneous lesions of Leishmania (Viannia) braziliensis (= L. braziliensis). A survey in Ceara State, Brazil indicated that 77% of persons (456 of 595) with parasitologically confirmed cutaneous leishmaniasis reported lymphadenopathy in addition to skin lesions. A group of 169 persons with recently diagnosed leishmaniasis and lymph nodes measuring > or = 2 cm in diameter (mean = 3.6 cm, maximum = 10.5 cm) underwent detailed clinical examination. Lymphadenopathy preceded the skin lesions in more than two-thirds of these, on the average by two weeks. Cultures of lymph node aspirates yielded Leishmania more frequently (86%) than cultures of aspirates of skin (53%) or biopsies of skin (74%). Parasites were isolated from the peripheral blood of one patient. Persons with lymphadenopathy gave a history of fever and had enlarged livers or spleens more often than a comparison group of 50 persons with cutaneous lesions but no lymphadenopathy. Persons with lymphadenopathy had more intense leishmanin skin reactions and lymphocyte proliferation following stimulation with specific antigens, whereas persons without lymphadenopathy had a higher frequency of previous infection. Isolates of parasites from both groups were identified as L. braziliensis. These data demonstrate the early spread of L. braziliensis beyond the skin and suggest differences in host immunity between persons with and without lymphadenopathy. Leishmaniasis braziliensis should be considered in cases of unexplained lymphadenopathy in endemic areas.

Sugar meal sources for the phlebotomine sandfly Lutzomyia longipalpis in Ceará State, Brazil.

In the Brazilian village of Boqueirão do Renato Parente, Ceará State, where visceral leishmaniasis is endemic, significant variation in the abundance of phlebotomine sandflies between different types of vegetation was demonstrated by castor oil sticky trap collections. Population densities of Lutzomyia longipalpis (Lutz & Neiva) sandflies were higher in beans and maize crops than in the surrounding open and tree scrub. Significant relationships were detected between the abundances of sandflies and aphids, suggesting aphid honeydew as a potential food source. Sugar meal analysis, using high-performance anion exchange (HPAE) chromatography with pulsed amperometric detection (PAD) and the cold anthrone test, was used to demonstrate that significantly more sandflies fed on bean plants contaminated with aphids and honeydew than on uncontaminated beans. Furthermore, higher concentrations of sugars were detected in flies which fed on aphid/honeydew-contaminated beans, suggesting that sugar was more easily available and/or that honeydew/aphids act as phagostimulants for sandflies. Amongst wild sandflies collected from a bean field, significantly more female sandflies were 'sugar-positive' than males, though the sugar concentrations in positive sandflies were similar for both sexes. The concentrations of di- and trisaccharides in sandfly homogenates, honeydew extracts and phloem exudates were very low.

Cutaneous leishmaniasis in Ceara state in northeastern Brazil: incrimination of Lutzomyia whitmani (Diptera: Psychodidae) as a vector of Leishmania braziliensis in baturite municipality.

Baturite is an important endemic zone of American cutaneous leishmaniasis in the state of Ceara, where an entomologic survey has been carried out to obtain information about transmission of the disease. From October 1989 through August 1991, natural infections with flagellates were detected in 34 of 3,000 Lutzomyia whitmani, five of 1,667 Lu. migonei, three of 5,278 Lu. wellcomei, one of 646 Lu. shannoni, and one of 21 Lu. evandroi. Thirty-five infections were peripylarian (i.e., behind the pylorus in the sand fly gut with a tendency to invade the midgut anterior to the pylorus). Fifteen infections (14 from Lu. whitmani and one from Lu. migonei) have been characterized as Leishmania (Viannia) braziliensis by isoenzyme electrophoresis, incriminating this species as a vector of the parasite in this area. Other possible vectors include Lu. wellcomei, Lu. migonei, and Lu. shannoni. Transmission appears to occur in peridomestic sites, especially around animal enclosures. Most cases of cutaneous leishmaniasis were recorded between September and December in Baturite during the period of study.

American cutaneous leishmaniasis: in situ characterization of the cellular immune response with time.

The cellular nature of the infiltrate in the skin of patients with American cutaneous leishmaniasis was characterized by immunohistochemistry. The study population consisted of patients in Ceara, Brazil, an area where Leishmania braziliensis is endemic. Biopsies were taken from lesions present for 0.5-4 months duration and sections were stained with antibodies to T cells, T cell subsets, B cells, and macrophage markers to quantitate these cell types. The T cells accounted for 37.0 +/- 7.6% (mean +/- SD) of the infiltrate. The average percentages of CD4- and CD8-positive T cells were similar to each other, 20.4 +/- 9.0% and 19.9 +/- 6.7%, respectively. Interleukin-2 receptor-positive cells and B cells were infrequent, 3.7 +/- 3.0% and 2.3 +/- 3.1%, respectively. When the relationship between the age of the lesion at biopsy and the cellular phenotype was examined, it was noted that the percentage of positive cells remained fixed for all cell types except for that of gamma delta cells, which decreased with time. It is likely that gamma delta T cells are important in the early phase of the immune response to L. braziliensis and may, in general, be important in the early immune response of granulomatous diseases.

The identity of Leishmania isolated from sand flies and vertebrate hosts in a major focus of cutaneous leishmaniasis in Baturite, northeastern Brazil.

During a field investigation carried out in Baturite, Brazil from 1989 to 1991, sand flies, sympatric rodents, domestic dogs and humans were surveyed for leishmaniasis. Twenty strains of Leishmania were isolated by in vitro culture from Lutzomyia whitmani, three strains were obtained from Rattus rattus, two strains from dogs, and five strains from humans. The isolates were characterized by isoenzyme electrophoresis by hybridization with kinetoplast DNA-specific probes. All the samples were identified as L. (Viannia) braziliensis. The importance of these results in the dynamics of the Leishmania infection in this focus is discussed.

Potential role for interleukin-10 in the immunosuppression associated with kala azar.

Patients with acute kala azar are generally nonreactive in a number of immunologic assays, including T cell proliferation and generation of macrophage-activating cytokines, principally IFN-gamma, in response to leishmania antigens in vitro. To test for potential immunosuppressive factors, a series of T cell lines and clones were established from patients with acute kala azar, from patients after chemotherapy for kala azar, and from skin test-positive adults from the same endemic region. Although CD4+ T cell lines and clones could be readily established from the skin test-positive adults, lines and clones from acute or treated patients were heavily biased in expression of CD8+. The CD8+ cells from acute patients did not themselves release cytokines in response to leishmania antigens in vitro, but markedly affected the cytokine profile of peripheral blood mononuclear cells isolated 1 yr later after recovery. Addition of the CD8+ cells caused inhibition of lymphoproliferation and IFN-gamma release, with augmentation of IL-6 and IL-10 release. The inhibitory effects of the CD8+ cells could be partially abrogated by antibodies to IL-10 but not by antibodies to IL-4. Analysis of four patients with acute kala azar demonstrated release of IL-10 that could not be demonstrated in supernatants from asymptomatic skin test-positive individuals. Generation of IL-10 may contribute to the profound suppression of IFN-gamma release that occurs during kala azar due to Leishmania chagasi.

Correlates of Leishmania-specific immunity in the clinical spectrum of infection with Leishmania chagasi.

Patients from across the spectrum of clinical manifestations of Leishmania chagasi infection were evaluated for in vitro correlates of immunity. Peripheral blood mononuclear cells were assayed for parasite-specific lymphoproliferation, cytokine generation, and the capacity to activate autologous macrophages to kill intracellular amastigotes. Patients with acute kala-azar were generally unreactive in each of these assays. Children with subclinical infection demonstrated relatively low levels of proliferation and interferon-gamma production, but none went on to develop overt kala-azar during the study. Patients evaluated after therapy for kala-azar demonstrated yet higher levels of lymphoproliferation and cytokine generation and produced low but significant levels of cytokines in vitro in response to parasite antigens, but not during the activation of infected macrophages. Finally, peripheral blood mononuclear cells from adults with positive delayed-type hypersensitivity responses and no history of kala-azar showed the broadest reactivity in vitro. These patients' cells generated the largest amounts of activating cytokines in vitro during the activation of autologous macrophages to a leishmanicidal state.

[Cutaneous parasitism by Leishmania (Leishmania) chagasi during South American visceral leishmaniasis]. / Parasitisme cutané par Leishmania (Leishmania) chagasi au cours de la leishmaniose viscérale sud-américaine.

Eighteen patients from the northeastern Brazilian State of Ceara with proven kala-azar were studied for evidence of skin parasitism: two had ulcerative or papular skin lesions and 16 had clinically normal skin. Punch biopsies (3 mm) of intact paraspinal subscapular skin were performed on all patients; in those with papular or ulcerative lesions biopsies also were taken from an active site. One of each of the subscapsular biopsies and half of each biopsy from an active lesion were studied; the other specimens were seeded on NNN Difco Blood Agar Base Medium for parasite culture. The biopsies revealed a discrete to intense mononuclear inflammatory infiltrate, predominantly perivascular in nature. No amastigotes were observed in any tissue sections but 7 of the 18 patients yielded promastigotes on skin culture identified by monoclonal antibodies and by enzyme electrophoresis as Leishmania (Leishmania) chagasi [L. (L.) chagasi]. The isolation of Leishmania (Leishmania) chagasi, the recognized aetiologic agent of visceral leishmaniasis in the New World, from the skin of nearly 40% of 18 AVL patients proves dermatotropism of L. (L.) chagasi occurs and may be frequent in neotropical human visceral leishmaniasis (AVL.). Infected persons with skin parasites could act as a reservoir of infection and allow human to human transmission.

Epidemiology of visceral leishmaniasis in northeast Brazil.

Epidemiologic aspects of the relationship between infection with Leishmania chagasi and development of clinical visceral leishmaniasis (VL) were studied in all children < 11 years old in a defined, endemic, rural area of the state of Ceará in northeast Brazil. Antileishmanial antibodies were measured in the same subjects by ELISA on six occasions between May 1987 and August 1989. Seroconversion was documented during this period in 108 children, with a cumulative annual incidence of 4.6%. Twelve (11.1%) of these children developed VL. Age < 4 years, hematocrit < 33%, and living in the mountains predicted the development of clinically apparent VL after seroconversion. Despite a high percentage of dogs serologically positive in the region (38%), there was no increased risk of infection for children living in the same household with dogs. Since children in households with a prior case of VL had a threefold increased risk of infection, human-sandfly-human transmission might have been important.

Laboratory evaluation of Brazilian Mesocyclops (Copepoda: Cyclopidae) for mosquito control.

In laboratory tests, four different strains of Mesocyclops aspericornis (Daday) collected in or near Fortaleza, Brazil, showed potential as biological control agents of Aedes aegypti (L.) mosquito larvae but were not as effective against Anopheles or Culex. In contrast, the larger M. longisetus (Thiebaud), collected at Fortaleza, killed 100% of Ae. aegypti and Anopheles farauti (Laveran) (No. 1) at larval densities of 200/liter and Culex quinquefasciatus (Say) at 25/liter. In cage simulations with Ae. aegypti and Mesocyclops, both copepod species eliminated all immatures in earthenware pots by week 3. Owing to the lack of replacement, all Ae. aegypti adults subsequently died by week 8 or 9. Although both M. longisetus and M. aspericornis showed maximum reproductive potential at 25 degrees C, breeding occurred from 20 to 35 degrees C. Based on these laboratory evaluations, M. longisetus has been selected for field trials in rural villages in Ceará to control Ae. aegypti.

Phlebotomine sandfly (Diptera: Psychodidae) fauna survey in an American cutaneous leishmaniasis (ACL) focus in Baturité, Ceará State, northeast Brazil.

From October until July 1991, CDC miniature light traps were set up and man and animal-landing and biting catches were made in 100 different catching zones, in different habitats, throughout the ACL focus of the Serra de Baturité. Female Lutzomyia whitmani and Lu. wellcomei appeared to be highly anthropophilic and were the most prevalent species in man-landing catches in peridomestic sites. Most Lu. migonei were attracted to animals, especially mules. Seasonal fluctuations and habitat preference were noted for the principal populations present.

Canine visceral leishmaniasis in northeast Brazil: assessment of serodiagnostic methods.

Domestic dogs are considered to be a major reservoir of Leishmania donovani chagasi in northeast Brazil, and the elimination of infected dogs is an important part of the control program. We assessed 2 serological methods, IFA and ELISA. Of 405 dogs, 8% were positive by IFA obtained from blood collected by drying onto filter paper followed by elution, 17% were positive by IFA performed using sera, and 38% were positive by ELISA on the same sera. Thirty-five dogs, seropositive by 1 or more of the above tests, were killed and touch preparations were made of liver, spleen, and mesenteric lymph nodes. Samples were cultured in enriched NNN media. The ELISA recognized all dogs with proven infection; IFA detected 10 of 12. Eleven dogs were positive by touch preparations and 7 by culture. In addition, kDNA hybridization was undertaken with probes to L. donovani chagasi, L. braziliensis ssp., and L. mexicana amazonensis. Positive results were obtained from tissue in 19 instances, but 10 culture positive specimens were not recognized.

Evaluation of antibody responses in American visceral leishmaniasis by ELISA and immunoblot.

American visceral leishmaniasis (AVL) is an important disease among children of northeast Brazil. In order to characterize antibody responses during AVL, sera of hospitalized patients were analyzed by ELISA and Western blot using a Leishmania chagasi antigen preparation. The ELISA was positive (absorbance greater than or equal to 0.196) at a serum dilution of 1:1024 in all patients at presentation, and fell to ward control levels over the following year. Only one of 72 control subjects tested positive, and that donor had a sibling with AVL. Immunoblots of the patients' sera recognized multiple bands, the most frequent of which were at approximately 116 kDa, 70 kDa, and 26 kDa. Less frequently observed were bands at approximately 93 kDa, 74 kDa, 62 kDa, 46 kDa and 32 kDa. The ELISA responses and patterns of banding were distinctive for AVL, and could be used to differentiate patients with AVL from those with Chagas' disease or cutaneous leishmaniasis. Sera from six AVL patients followed for up to six weeks after treatment identified no new bands. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of surface iodinated parasite proteins showed one major band and four minor bands, whereas SDS-PAGE of biotinylated parasite proteins revealed a banding pattern similar to those of patient sera. AVL appears to produce characteristic immunoblot patterns which can be used along with a sensitive screening ELISA to diagnose AVL.

Epidemiological studies on American leishmaniasis in Ceará State, Brazil. Molecular characterization of the Leishmania isolates.

Two methods of molecular characterization, using monoclonal antibodies and enzyme electrophoresis, were employed in the identification of 36 stocks of Leishmania isolated from human and canine cases of American visceral (AVL) and cutaneous (ACL) leishmaniases in the northern part of Ceará State, Brazil. Molecular homogeneous strains of Leishmania donovani (chagasi) isolated from both human and canine hosts were detected in 14 municipalities. Two more parasite species, L. braziliensis braziliensis and L. mexicana amazonensis, were also detected in the state. The implication of these results with respect to both the clinical and epidemiological data are discussed.

Human mononuclear phagocyte differentiation: a study of the U-937 cell line by ultrastructural cytochemistry and surface antigen analysis.

U-937 represents a well-established permanent human haematopoietic cell line, which exhibits characteristics of the monocyte/macrophage series. U-937 cells were investigated by peroxidase ultrastructural cytochemistry in order to determine the normal developmental stage to which they correspond. This study was performed in non- and TPA-stimulated cells, in conjunction with surface analysis by monoclonal antibodies. It is concluded: (1) peroxidase-positive U-937 cells are monoblasts and promonocytes involved in myeloperoxidase synthesis; (2) TPA-stimulation caricatures transformation of these cells into monocytes but not into resident macrophages, as far as peroxidase cytochemistry is concerned; (3) the reactivity of myeloperoxidase present in the endoplasmic reticulum of synthesizing cells is inhibited by glutaraldehyde fixation.