Experimental effect of feeding on ricinus communis and bougainvillea glabra on the development of the sand fly phlebotomus papatasi [diptera: psychodidae] from Egypt

Plants are promising sources of agents useful for the control of vectors of human diseases including leishmaniasis. The effect of Ricinus communis [Euphorbiaceae] and Bougainvillea glabra [Nyctaginaceae] on transmission of leishmaniasis was investigated using them as diets for Phlebotomus papalasi to monitor their effect on life-history traits. P. papatasi were allowed to feed separately on both plants then offered a blood-meal. Fed-females were observed daily for egg-laying and subsequent developmental stages. P. papatasi was able to feed on B. glabra [29.41% females and 46.30% males] and R. communis [5.80% females and 10.43% males]. 34.28% of females died within 24-48 hours post-feeding on R. communis, whereas, it was 16.5% in females fed on B. glabra. Overall fecundity of surviving females was reduced compared to controls, reared on standard laboratory diet; however there was no effect on the sex ratio of progeny. Female P. papatasi in the control group had significantly longer life span compared to plant-fed group. Feeding on these plants not only decreased sand fly survival rates but incurred negative effects on fecundity. Findings indicate that planting high densities of R. communis and B. glabra in sand flies-endemic areas will reduce population sizes and reduce the risk of Leishmania major infections

Avaliação do papel do receptor marco na infecção de macrófagos murinos por Leishmania major / Evaluation of the role of the receptor in March infection of murine macrophages with Leishmania major

Camundongos CBA são resistentes à infecção por Leishmania major e permissivos à infecção por L. amazonensis. Adicionalmente, macrófagos de camundongos CBA controlam à infecção por L. major, mas não por L. mazonensis in vitro. Em estudo comparativo realizado por nosso grupo foi demonstrado que o receptor scavenger MARCO teve expressão aumentada em resposta à infecção por L. major, mas não na infecção por L. amazonensis. Ainda, o bloqueio do receptor com o anticorpo específico reduziu a infecção por L. major em 30%, indicando que esta proteína tem participação no reconhecimento de promastigotas de L. major em macrófagos de CBA. Assim, nossa hipótese é que o receptor MARCO participa do reconhecimento e fagocitose de L. major por macrófagos, direcionando o curso da infecção. O objetivo do presente estudo consistiu em evidenciar o papel do receptor MARCO na infecção de macrófagos por L. major. Inicialmente, células J774 foram transfectadas com os vetores pcDNA3.1-MARCO (J774-MARCO) ou pcDNA3.1 (J774-MOCK)...

CBA mice are resistant to Leishmania major yet permissive to L. amazonensis infection. In addition, CBA macrophages control L. major, but not L. amazonensis infection in vitro. In a comparative study performed by our group increase in expression of the scavenger receptor MARCO has been detected in response to L. major, but not to L. amazonensis infection. Moreover, ED31 monoclonal antibody against MARCO reduced by 30% L. major infection in CBA macrophages. These findings indicate that MARCO plays a role in L. major recognition by CBA macrophages. We hypothesized that MARCO receptor participates in the recognition and phagocytosis of L. major by macrophages, directing the outcome of infection. In the present study, we aimed to further disclose the role MARCO plays in L. major infection of murine macrophages. First J774 cells were transfected with pcDNA3.1-MARCO vector (MARCO-J774) or pcDNA3.1 vector (MOCK-J774)...

Vectorial competence of phlebotomus papatasi [diptera: psychodidae] to transmit two old world leishmania species: leishmania major and L. tropica

The vectorial competence of Phlebotomus papatasi for two old world Leishmania species, L. major and L. tropica was investigated. Phlebotomus papatasi originally collected from Suez Governorate, were membrane fed on homogenized hamster's lesion infected with L. major, MHOM/EG/06/RTC-63, and L. tropica, MGER/EG/06/RTC-74 identified from patients with suspected CL in Northern Sinai, Egypt. Fed flies were dissected at different time intervals and examined microscopically to determine the infection rate and parasite intensity. The feeding rate of P. papatasi on L. major [58.69%] was found higher than on L tropica [45.99%]. Infection rate with L. major [60.19%] was significantly higher than that with L. tropica [39.73%]. Transmission by bites in case of P. papatasi/L. tropica failed. A characteristic L. major lesion was developed on the foot pads region 120 days post infective bites on healthy hamster. It is therefore concluded that P. papatasi is a much more effective vector for L. major than for L. tropica

[Identification of species of leishmania isolated from patients with cutaneous leishmaniasis in Kermanshah; using RAPD-PCR technique]

Annually many numbers of pationts with Cutaneous Leishmaniasis [CL] have been reported in Kermanshah province- IRAN. The study aimed to identify species of Leishmania isolated from patients with CT in Kermanshah. Seven isolates of Leishmania obtained from patients with CL, without any travelling to other provinces, were cultured in NNN medium. After mass production of leptomonads in RPMI 1640 medium DNA was purified and the species were diagnosed using RAPD-PCR technique. The study of electrophoretic fingerprints of the product of RAPD-PCR in seven isolates showed that Leshmania major was the causative agent of CL patients in Kermanshah province. More studies in this field recommended

Evaluation of miltefosine against Leishmania major [MRHO/IR/75/ER]: In vitro and vivo studies

Cutaneous leishmaniasis is endemic in 88 different countries. There are an estimated 1.5 million new cases each year, with over 90% occurring in Afghanistan, Algeria, Iran, Iraq, Saudi Arabia, Syria [Old World] and in Brazil and Peru [New World]. Miltefosine is effective in vitro and in vivo against Leishmania species and it was demonstrated efficacy in animals via the oral route. This study is the first one for evaluating the effect of miltefosine on cutaneous leishmaniasis of L. major [MRHO/IR/75/ER] by in vivo and in vitro studies in the BALB/c mouse model. As it was shown, miltefosine has a better effect on reduction of size of lesion compared to Glucantime[R], also it was not significant by statistical analysis. The results of this study show that miltefosine has a good activity against the proliferation of amastigotes of L. major. The results suggest that oral miltefosine might be a promising approach for developing new anti-Leishmanial drugs. [c] 2008 Tehran University of Medical Sciences. All rights reserved

Epidemiological study in a new focus of cutaneous leishmaniasis in the Islamic Republic of Iran

An outbreak of cutaneous leishmaniasis [CL] in Sabzevar county prompted this study of the epidemiology and the ecology of vectors and reservoirs. Examination of 541 schoolchildren showed rates of 9.4% for scars and 5.9% for ulcers. Among 807 inhabitants of 4 villages, 10.4% had scars and 3.0% had active lesions. The most highly infected age group was 0-4 years with a rate of 5.9%. A total of 12 849 sandflies representing 7 species were collected in the study area. Leptomonad infection was found in Phlebotomus papatasi, P. caucasicus and Sergentomyia sintoni. Parasites from man, P. papatasi and Rhombomys opimus, were isolated and characterized as Leishmania major. Based on this survey, this is an epidemic of zoonotic CL, with R. opimus the main reservoir host, and P. papatasi the main vector

Characterization of acid phosphatase in the promastigotes of three isolates of Leishmania major

Acid phosphatase [ACP] is suggested to be one of the virulence factors in leishmania and a correlation has been reported between Leishmanial acid phosphatase [ACP] activity and the severity of the disease in all types of leishmaniasis including zoonotic cutaneous leishmaniasis [ZCL], which is a polymorphic disease. Characterization of leishmania and its correlation with the severity of the skin lesions in zoonotic cutaneous leishmaniasis. Promastigotes were isolated from 30 patients with scaly flat ulcers [LP1], volcano-shaped lesions [LP2] and papular forms [LP3] of ZCL. The Km and Vmax values of ACP in the supernatant of lysed promastigotes were calculated in presence and absence of the enzyme inhibitors, fluoride, tartarate, phosphate and salicylate. The Michaelis-Menten substrate saturation kinetics exhibited Km values of 12.5, 16.0, 26.6 M and Vmax values of 8.78, 5.26 and 1.51 M/min/mg protein for LP1, LP2 and LP3, respectively. In all isolates, the ACP was inhibited by all four inhibitors but the percentage inhibition was different and each inhibitor showed a particular inhibition pattern for each promastigote preparation. ACP content of LP1 was more sensitive to all four inhibitors and fluoride was more potent inhibitor of the enzyme in three isolates. The differences in ACP kinetics may be interpreted as being consistent with the severity of the skin lesions in Leishmania major infection

Caracterização dos leucócitos e da produção de quimiocinas envolvidas na resposta imuno-inflamatória in situ de camundongos CBA infectados com Leishmania major ou Leishmania amazonensis / Characterization of leukocytes and production of chemokines involved in immune-inflammatory response in situ of CBA mice infected with Leishmania major or Leishmania amazonensis

Camundongos CBA infectados com L. major ou L. amazonensis apresentam perfis morfológicos distintos de resposta tecidual, relacionados, respectivamente, com resistência ou susceptibilidade. O perfil Th1, de resistência, é caracterizado por um infiltrado mononuclear misto, com aumento do número de linfócitos, necrose fibrinóide e formação de granulomas que culmina com cura das lesões. O perfil Th2, de susceptibilidade, apresenta um infiltrado macrofágico difuso, monomórfico, com intenso parasitismo e áreas de necrose lítica que resulta na morte dos animais. Esses diferentes perfis histopatológicos são determinados pelas células efetoras da resposta imuno-inflamatória e por citocinas e quimiocinas. A caracterização da resposta imuno-inflamatória relacionada com infecção por diferentes espécies de Leishmania pode trazer informações importantes quanto a patogênese das mesmas e oferecer subsídios à sua modulação. Avaliamos comparativamente a infecção de camundongos CBA com L. major (Lm), L. amazonensis (La), em diferentes períodos, em relação à constituição celular nos linfonodos popliteos e a caracterização do infiltrado inflamatório das lesões através das técnicas de imunohistoquímica e RT-PCR. Nos linfonodos de drenagem das lesões foi observado aumento no número de células MAC-1+ nos grupos infectados. No grupo La houve aumento no número de células T CD4+ e S, enquanto no grupo Lm houve aumento crescente na quantidade de células T CD8+. Nos infiltrados inflamatórios das lesões, foi observada uma maior expressão de RNAm para as moléculas TNF-a, MIG e CRG-2 no grupo Lm. Somente a expressão de RNAm para IL-4, detectada na fase tardia, foi maior...

Adjuvant effect of leishmania major promerstigotes on the immune response of mice to ovalbumin

The immune responses of mice immunized with ovalbumin [OVA] together with killed L. major [KLM] promastigotes as adjuvant were studied. Three doses [5 ' 107, 1 ' 108 and 2 ' 108] of KLM combined with OVA [100 micro g] were injected into the groups of C57BL/6 mice. BCG and complete Freund's adjuvant [CFA] were used as control adjuvants. Lymphocyte proliferation and antibody titers were determined, and IFN-gamma and IL-4 were measured in the supernatants of lymph node cell cultures. Results showed that immunization using OVA mixed with KLM enhanced the in vitro proliferative response of T-cells to the antigen and resulted in the production of increased levels of IFN-gamma [2800-3700 pg/ml] relative to the mice injected with OVA alone [1750 pg/ml]. In the mice receiving OVA + 5 ' 107 KLM, the production of IL-4 remained lower [18, 20 pg/ml] than OVA alone [105, 109 pg/ml] and almost was similar to that of observed in mice inoculated with OVA + BCG, leading to high IFN-gamma /IL-4 ratios. Using higher doses of KLM [1 ' 108], the IL-4 responses were of the same magnitude as or higher than the responses of mice inoculated with OVA + CFA. Antibody titers to OVA were also strongly boosted at the highest KLM dose. These findings indicate that KLM may function as an adjuvant, and its dose plays a role in the eventual outcome of the response. Inoculation of the mice with a low dose of KLM [5 ' 107] tends to promote a Th1-type response

Vector-host-parasite inter-relationships in leishmaniasis. II-Influence of blood meal from natural vertebrate hosts with and without leishmaniasis infantum and L. major on the proteolytic activity in the gut of phlebotomus langeroni [diptera: Psychodidae]

Proteolytic activity in the gut of Phlebotomus langeroni [Nitzulescu] was studied at 4 subsequent 24-hour intervals post feeding on human, dog [Canis familiaris], rat [Rattus rattus] and turkey [Melagris gallopava] blood with and without Leishmania infantum or L. Major promastigotes. The gut proteolytic activity increased gradually after feeding to reach a maximum at 48 hours post feeding on any of the 12 studied blood meals. In all cases, the activity declined after 48 hours and almost terminated by 96 hours. In case of normal blood, the proteolytic activity, at 48 hours post feeding, was the highest in case of the dog, followed by human, rat and turkey, respectively. Promastigotes were alive and active in fresh gut smears of P. langeroni fed on human, dog and rat blood mixed with either L. infantum or L. major, throughout the digestion period [1 - 4 days]