Coinfection by Toxoplasma gondii and Leishmania spp. in domestic cats (Felis catus) in State of Mato Grosso do Sul

Introduction Leishmaniasis and toxoplasmosis are important to public health. Methods Antibodies for Toxoplasma gondii and Leishmania spp. were evaluated in cats from Campo Grande, State of Mato Grosso do Sul, Brazil, a region endemic for canine visceral leishmaniasis. Serum samples from 50 asymptomatic cats were titrated for T. gondii by the immunofluorescence antibody test and modified agglutination test and for Leishmania spp. by the immunofluorescence antibody test. Results These two agents coinfected two (4%) of the 50 tested animals. Conclusions These findings demonstrate the concomitant presence of two important zoonoses in cats from Brazilian endemic regions for canine visceral leishmaniasis.

Leishmania, Babesia and Ehrlichia in urban pet dogs: co-infection or cross-reaction in serological methods?

INTRODUCTION: The present study was designed to assess the occurrence of co-infection or cross-reaction in the serological techniques used for detecting the anti-Leishmania spp., -Babesia canis vogeli and -Ehrlichia canis antibodies in urban dogs from an area endemic to these parasites. METHODS: The serum samples from dogs were tested for the Babesia canis vogeli strain Belo Horizonte antigen and Ehrlichia canis strain São Paulo by immunofluorescence antibody test (IFAT) and by anti-Leishmania immunoglobulin G (IgG) antibody detection to assess Leishmania infection. We used the following four commercial kits for canine visceral leishmaniasis: ELISA, IFAT, Dual Path Platform (DPP) (Bio Manguinhos(r)/FIOCRUZ/MS) and a rK39 RDT (Kalazar Detect Canine Rapid Test; Inbios). RESULTS : Of 96 serum samples submitted to serological assays, 4 (4.2%) were positive for Leishmania as determined by ELISA; 12 (12.5%), by IFAT; 14 (14.6%) by rK39 RDT; and 20 (20.8%), by DPP. Antibodies against Ehrlichia and Babesia were detected in 23/96 (23.9%) and 30/96 (31.2%) samples, respectively. No significant association was identified between the results of tests for detecting Babesia or Ehrlichia and those for detecting Leishmania (p-value>0.05). CONCLUSIONS: In the present study, we demonstrated co-infection with Ehrlichia or Babesia and Leishmania in dogs from Minas Gerais (Brazil); we also found that the serological tests that were used did not cross-react.

Expression of annexin A1 in Leishmania-infected skin and its correlation with histopathological features

ABSTRACTINTRODUCTION:The aim of this study was quantify annexin A1 expression in macrophages and cluster of differentiation 4 (CD4) + and cluster of differentiation 8 (CD8)+ T cells from the skin of patients with cutaneous leishmaniasis (n=55) and correlate with histopathological aspects.METHODS:Infecting species were identified by polymerase chain reaction-restriction fragment length polymorphism, and expression of annexin A1 was analyzed by immunofluorescence.RESULTS:All patients (n = 55) were infected with Leishmania braziliensis . Annexin A1 was expressed more abundantly in CD163 + macrophages in infected skin (p < 0.0001) than in uninfected skin. In addition, macrophages in necrotic exudative reaction lesions expressed annexin A1 at higher levels than those observed in granulomatous (p < 0.01) and cellular lesions p < 0.05). This difference might be due to the need to clear both parasites and necrotic tissue from necrotic lesions. CD4 + cells in cellular lesions expressed annexin A1 more abundantly than did those in necrotic (p < 0.05) and granulomatous lesions (p < 0.01). Expression in CD8 + T cells followed the same trend. These differences might be due to the pervasiveness of lymphohistiocytic and plasmacytic infiltrate in cellular lesions.CONCLUSIONS:Annexin A1 is differentially expressed in CD163 + macrophages and T cells depending on the histopathological features of Leishmania -infected skin, which might affect cell activation.

Predictive factors for Leishmania infantum infection in dogs examined at a veterinary teaching hospital in Teresina, State of Piauí, Brazil

Abstract: INTRODUCTION: In Brazil, culling of seropositive dogs is one of the recommended strategies to control visceral leishmaniasis. Since infectiousness is correlated with clinical signs, control measures targeting symptomatic dogs could be more effective. METHODS: A cross-sectional study was carried out among 1,410 dogs, predictive models were developed based on clinical signs and an indirect immunofluorescence antibody test. RESULTS: The validated predictive model showed sensitivity and specificity of 86.5% and 70.0%, respectively. CONCLUSIONS: Predictive models could be used as tools to aid control programs in focusing on a smaller fraction of dogs contributing more to infection dissemination.

Isolation of an enriched plasma membrame subpellicular microtubule fraction of Leishmania mexicana amazonensis

A cell fractionation procedure previously developed for Trypanosoma cruzi was applied to isolated the plasma membrane of promastigotes of Leishania mexicana amazonensis. The cell, swollen in an hypotonic mediun, were disrupted in the presence of a nonionic detergent and the membrane fraction isolated by differencial centrifugation. Electron microscopy showed that the fraction consisted of pieces of the plasma membrane associated with subpellicular microtubules. It was also shown that this fraction is able to induce cell-mediated immune response in mice.

Studies on the relationship between lectin binding carbohydrates and different strains of Leishmania from the New World

The culture forms of L. mexicana pifanoi (LRC L-90), L. mexicana mexicana (LRC L-94, M-379); L. braziliensis braziliensis (LRC L-77, L-1, M-2903, H-LSS) and L. mexicana amazonensis (H-JMMO, M-JOF, H-21, H-PLL,M-1696) were tested with the following lectins: Canavalia ensiformis, Ricinus communis-120, Axinella polypoides, Phaseolus vulgaris, Evonymus europaeus, lotus tetragonolobus, Dolichos biflorus, Aaptos papillata II, Laburnum alpinum, Ulex europaeus, Arachis hypogaea and Soja hispida. All examined strains of Leishmania were agglutinated by C. ensiformis, R. communis-120 and A. popypoides. No agglutination reactions were observed with P. vulgaris, D.biflorus, A. papillata II, E. europaeus and L. tetragonolobus. Only L. m. pifanoi and the L. m. amazonensis strains H-JMMO and MJOF showed agglutination reactions with S. hispida, U. europaeus, L. alpinum and A. hypogaea, while L. m. mexicana (LRC L-94; M-379) strains, L. b. braziliensis H. LSS, LRC L-77; L-1; M-2903 and the L. m. amazonensis strains, H-PLL, H-21, M-1696 showed no agglutination reactions with these four lectins.

Morfometria amastigotica y desarrollo de cuatro aislados de Leishmania mexicana pifanoi de Venezuela em Lutzomyia townsendi

Utilizando parámetros biométricos de la fase amastigota y el tipo de desarrollo de los parásitos en el flebótomo Lutzomyia townsendi, se han estudiado cuatro aislados de Leishmania obtenidos de pacientes con leishmaniasis cutánea difusa, comparándolos con otros aislados de L. mexicana mexicana y L. braziliensis. Los resultados muestran una estrecha semejanza entre los cuatro aislados de pcientes anérgicos y la L. mexicana mexicana y sugieren que el nombre de L. mexicana pifanoi no parece sostenible; los cuatro aislados, por el contrario, podrían identificarse como L. mexicana amazonensis.

Bases experimentales para la identificacion de Leishmania spp. de America por morfometria de amastigotos

Estudios morfométricos sobre los amastigotos de dieciocho poblaciones de cuatro aislados pertenecientes a dos especies venezolanas de Leishmania (L. braziliensis y L. garnhami) indican que la posición del einetoplasto nose modifica en modo estadísticamente significativo cuando los parásitos son sometidos a pasajes por hamsteres y ratones,cultivos en medio NNN o por infección en un vector (Lu. townsendi). La posición del cinetoplasto, medido como la distancia entre el extremo posterior del amastigoto al cinetoplasto, dividido entre la distancia del organoide al extremo anterior de la célula, permite diferenciar a L. braziliensis de L. mexicana y L. garnhami. Los otros parámetros morfométricos no son tan confiables.

Factores dermicos que condicionan la infeccion de Lutzomyia townsendi (Ortiz, 1959) por Leishmania spp. de Venezuela

Se estudia la susceptibilidad de Lutzomyia townsendi a la infección con Leishmania spp. sobre lesiones experimentales de hamsteres. Se estudia la frecuencia y distribución de los amastigotos en la dermis, relacionándola con la profundidad que alcanza el estilete bucal del insecto. Una correlación positiva, con significante coeficiente de correlación, se establece entre la frecuencia de los parásitos a una profundidad de 100-150 nm en la dermis y el éxito de la infección de los flebótomos.

Ensayos metodologicos para la investigacion de reservorios de Leishmania spp en los Andes venezolanos

Se describen dos técnicas, presuntiva y confirmativa, para la investigación de mamíferos que pudieran ser reservorios de Leishmania que parasitan al hombre. Se investigan los cambios en los títulos de inmovilización y aglutinación de promastigotos de cultivo por los sueros de animales normales y expuestos una o varias veces a la inoculación intradérmica de pequeñas dosis de promastigotos vivos. Se registra una caída de los títulos de aglutinación en los sueros de hamsteres, de Holochilus venezuelae y de Didelphis marsupialis después de la inoculación con L. mexicana mexicana de Panamá y de L. gamhami de la región de los Andes venezolanos. Se discute la natureza de estos fenómenos. Se han hecho xenodiagnósticos con Lutzomyia townsendi en Holochilus venezuelae y Sigmodon hispidus infectados experimentalmente com L. mexicana mexicana, L. mexicana amazonensis, L. braziliensis y L. garnhami. Las pruebas fueron leidas mediante el examen microscópico de las gotitas de heces excretadas entre las 108 y 132 horas después de la ingesta infectante, tras colorearlas con Giemsa. Se obtuvieron resultados positivos en 23% de los experimentos usando mamíferos con lesiones localizadas, dejando a los flebótomos ingurgitarse libremente sobre animales anestesiados que poseian una hasta varias lesiones localizadas.

Atypical epidermal alterations in chronic Leishmania mexicana mexicana lesions fo C3H mice

C3H mice chronically infected with Leishmania m. mexicana, and in some groups treated with BCG or levamisole, presented atypical epidermal alterations, including pseudoepitheliomatous hyperplasia, hyperkeratosis and dysplasia. These alterations increased in frequency and intensity during the course of infection, but were not related to lesion size or tissue parasite load. Age matched normal, BCG and levamisole treated control mice, examined simultaneously, did not show epidermal modifications. In infected mice the dermis and hypodermis presented an inflammatory infiltrate of histiocytes, lymphocytes and plasma cells, accompanied at times by neutrophils and eosinophils, which did not vary with duration of infection.

Interaction of avirulent Leishmania species with rat peritoneal macrophages

An "in vitro" system has been developed for study of host cell-parasite interaction in visceral and cutaneous leishmaniasis. Avirulent promastigotes of L. brasiliensis and L. donovani, from strains originally isolated from human cases and mantained by serial culture in Davis' Medium were allowed to infect cultured macrophages from rat peritoneal exudate. Challenge of the macrophages by parasites took place in 199 medium, at 33ºC for L. brasiliensis and at 37ºC for L. donovani. Although the rat is resistant to infections by Leishmania spp., the promastigotes not only invaded the host cells, but transformed into amastigotes and later mutiplied, from 10 min after challenge to 24 hours later.

Host factors influencing outcome of Leishmania mexicana infection in mice

Studies were undertaken to determine the influence of several host-related parameters on the course of Leishmania mexicana mexicana infection in inbred C57B1/10 (C57) and outbred albino (OA) mice. An important influence of the following variables was demonstrated: Host strain: lesions in C57s were significantly less variable in size and outcome than those of OAs under the conditions studied and even when persistent developed at a slower rate. Host age: Subcutanous injection of 2 x 10 [raised to the power of 4] to 2 x 10 [raised to the power of 6] amastigotes into the dorsum of the rear paw produced significantly larger lesions which healed more slowly in 2 mo. old C57s than in 4 mo. old mice. Reduced healing ability was observed in older (8 mo. old) female C57s, and low mortality occurred after 15 months of age in infected mice of both sexes. Lesion site: Following amastigote infection, lesions in paws of most C57s regress within 15 - 25 wks. In contrast, perinasal legions produced with the same number of parasites tend to persist for the life of the animal as slowly spreading irregular nodules. In animals infected in both locations, each lesion site behaves similarly to that in singly infected animals of the same age, i.e. regression in the two sites is independent. Our results indicate that while host strain may strongly influence infection outcoem, such variables as lesion site and host age play important roles and may explain, in part, reported inter- and intraexperimental variability in responses of murine hosts to a given leishmanial parasite.