Parasitology Unit

Berlin, Germany

Parasitology Unit

Berlin, Germany

Time filter

Source Type

Annoura T.,Jikei University School of Medicine | Kenthirapalan S.,Parasitology Unit | Matuschewski K.,Max Planck Institute for Infection Biology | Ramesar J.,Leiden University | And 3 more authors.
Molecular Microbiology | Year: 2016

Multidrug resistance (MDR) proteins belong to the B subfamily of the ATP Binding Cassette (ABC) transporters, which export a wide range of compounds including pharmaceuticals. In this study, we used reverse genetics to study the role of all seven Plasmodium MDR proteins during the life cycle of malaria parasites. Four P. berghei genes (encoding MDR1, 4, 6 and 7) were refractory to deletion, indicating a vital role during blood stage multiplication and validating them as potential targets for antimalarial drugs. Mutants lacking expression of MDR2, MDR3 and MDR5 were generated in both P. berghei and P. falciparum, indicating a dispensable role for blood stage development. Whereas P. berghei mutants lacking MDR3 and MDR5 had a reduced blood stage multiplication in vivo, blood stage growth of P. falciparum mutants in vitro was not significantly different. Oocyst maturation and sporozoite formation in Plasmodium mutants lacking MDR2 or MDR5 was reduced. Sporozoites of these P. berghei mutants were capable of infecting mice and life cycle completion, indicating the absence of vital roles during liver stage development. Our results demonstrate vital and dispensable roles of MDR proteins during blood stages and an important function in sporogony for MDR2 and MDR5 in both Plasmodium species. © 2016 John Wiley & Sons Ltd.


Hamainza B.,Operational Research Unit | Moonga H.B.,Parasitology Unit | Chalwe V.,Tropical Diseases Research Center | Pagnoni F.,World Health Organization
Malaria Journal | Year: 2011

Background: Access to prompt and effective treatment is a cornerstone of the current malaria control strategy. Delays in starting appropriate treatment is a major contributor to malaria mortality. WHO recommends home management of malaria using artemisininbased combination therapy (ACT) and Rapid Diagnostic tests (RDTs) as one of the strategies for improving access to prompt and efective malaria case management. Methods. A prospective evaluation of the effectiveness of using community health workers (CHWs) as delivery points for ACT and RDTs in the home management of malaria in two districts in Zambia. Results: CHWs were able to manage malaria fevers by correctly interpreting RDT results and appropriately prescribing antimalarials. All severe malaria cases and febrile non-malaria fevers were referred to a health facility for further management. There were variations in malaria prevalence between the two districts and among the villages in each district. 100% and 99.4% of the patients with a negative RDT result were not prescribed an antimalarial in the two districts respectively. No cases progressed to severe malaria and no deaths were recorded during the study period. Community perceptions were positive. Conclusion: CHWs are effective delivery points for prompt and effective malaria case management at community level. Adherence to test results is the best ever reported in Zambia. Further areas of implementation research are discussed. © 2011 Chanda et al; licensee BioMed Central Ltd.


Hamainza B.,Operational Research Unit | Moonga H.B.,Parasitology Unit | Chalwe V.,Tropical Diseases Research Center | Banda P.,Ministry of Health | Pagnoni F.,World Health Organization
Malaria Journal | Year: 2011

Background: Malaria case management is one of the key strategies to control malaria. Various studies have demonstrated the feasibility of home management of malaria (HMM). However, data on the costs and effectiveness of artemisinin-based combination therapy (ACT) and rapid diagnostic tests via HMM is limited. Method. Cost-effectiveness of home management versus health facility-based management of uncomplicated malaria in two rural districts in Zambia was analysed from a providers' perspective. The sample included 16 community health workers (CHWs) and 15 health facilities. The outcome measure was the cost per case appropriately diagnosed and treated. Costs of scaling-up HMM nationwide were estimated based on the CHW utilisation rates observed in the study. Results: HMM was more cost effective than facility-based management of uncomplicated malaria. The cost per case correctly diagnosed and treated was USD 4.22 for HMM and USD 6.12 for facility level. Utilization and adherence to diagnostic and treatment guidelines was higher in HMM than at a health facility. Conclusion: HMM using ACT and RDTs was more efficient at appropriately diagnosing and treating malaria than the health facility level. Scaling up this intervention requires significant investments. © 2011 Chanda et al; licensee BioMed Central Ltd.


PubMed | Parasitology Unit and AZ Electronic
Type: | Journal: Parasitology international | Year: 2016

During its intra-erythrocytic development, the malaria parasite Plasmodium falciparum synthesizes insoluble hemozoin (HZ) crystals that are released into the circulation upon rupture of parasitized red blood cells, and rapidly phagocytized by host mononuclear cells. Here, HZ persists undigested, causing functional impairment and possibly leading to increased host susceptibility to secondary infections. In patients with malaria and visceral leishmaniasis (VL) co-infections, HZ-loaded macrophages are likely to co-harbor Leishmania donovani parasites, but whether this might influence the course of the Leishmania infection is unknown. In this study, L. donovani amastigote growth was monitored in mouse RAW 264.7 macrophages and PMA-differentiated THP-1 cells previously exposed to increasing amounts of HZ or its synthetic analogue -hematin (BH). Latex beads were used as a phagocytic control. Data demonstrate that phagocytosis of HZ and BH by RAW 264.7 cells promoted infection therein by L. donovani parasites in a dose-dependent fashion. Similar results were not observed when using THP-1 cells, despite a clear persistence of undigested heme up to 48h after phagocytosis. Conditioning with lipopolysaccharide (LPS)/interferon (IFN)- prior to Leishmania infection triggered the release in RAW 264.7 cells of nitric oxide (NO), a highly leishmanicidal metabolite. However, neither HZ nor BH pre-ingestion were able to inhibit NO production following stimulation with LPS/IFN-, suggesting that the HZ- and BH-promoting effect on L. donovani infection occurred with an NO-independent mechanism. In conclusion, these preliminary findings highlight a possible detrimental effect of HZ on the course of VL, warranting further investigation into the clinical relevance of the current models.


Igbeneghu C.,Ladoke Akintola University of Technology | Odaibo A.B.,Parasitology Unit | Olaleye D.O.,University of Ibadan
Medical Principles and Practice | Year: 2011

Objective: To determine the prevalence of asymptomatic malaria among prospective blood donors and its effect on some hematological parameters. Subjects and Methods: Six hundred sixty-eight seemingly healthy individuals (501 men and 167 women) ≥16 years of age and without clinical symptoms in Iwo, Southwestern Nigeria, were screened for this study. A sample of 5 ml of blood was drawn from each participant for examination of malaria parasites and a full blood count. Thick and thin Giemsa-stained blood smears were prepared for malaria parasite identification and quantification. Estimations of hematocrit, hemoglobin concentration, and platelet and leukocyte counts were made using an automated Coulter counter (STKS model). Results: Out of the 668 participants examined, 141 (21.1%) were positive for malarial parasitemia. The parasite rate was significantly higher in men (25.5%) than in women (7.8%) (χ 2 = 23.29, p < 0.001) and it was significantly associated with age (χ 2 = 33.69, p < 0.001). Parasitemic participants had significantly lower mean values of hematocrit, hemoglobin concentration, and total leukocyte and platelet counts compared to aparasitemic individuals (t = 3.5, p < 0.001; t = 2.0, p = 0.04; t = 4.4, p < 0.001, and t = 5.3, p < 0.001, respectively). A low platelet count (<150 × 10 9/l) was significantly associated with malarial infection (OR 4.0; 95% CI 2.6-6.1). A person with a platelet count <150 × 10 9/l was 4 times more likely to have asymptomatic malarial infection than one with a count ≥150 × 10 9/l. Conclusion: Asymptomatic malaria is prevalent among blood donors in the study area and is associated with thrombocytopenia. Copyright © 2011 S. Karger AG, Basel.


Mendes R.E.,University of Cordoba, Spain | Perez-Ecija R.A.,University of Cordoba, Spain | Zafra R.,University of Cordoba, Spain | Buffoni L.,Parasitology Unit | And 4 more authors.
Vaccine | Year: 2010

Protection against Fasciola hepatica in goats immunized with Peroxiredoxin (Prx) was assessed. The experimental trial consisted of three groups of seven animals; group 1 were unimmunized and uninfected, group 2 were immunized with adjuvant only and group 3 were immunized with recombinant Prx in adjuvant (immunized and infected). Immunization with Prx in Quil A adjuvant, group 3, induced a reduction in fluke burden of 33.04% when compared to adjuvant control, group 2, although this difference was not significant. The hepatic gross and microscopical morphometric study revealed lower damage in the Prx-immunized compared to group 2 (p < 0.05). Furthermore, immunohistochemical studies revealed that the Prx-immunized group exhibited reduced infiltration of CD4+, CD8+, IFN-γ+ and TCR+ (p < 0.05); and CD2+ and IL-4+ (p < 0.001) in hepatic lesions. Levels of anti-Prx serum IgG in group 3 showed a significant increase at the 4th week after challenge infection compared with group 2 (p < 0.0001). This is the first report of ruminant immunization with recombinant Prx of F. hepatica. The study shows that this vaccine significantly reduces hepatic damage and encourages further studies to improve the vaccine efficacy. © 2010 Elsevier Ltd.


PubMed | Parasitology Unit, Dr Burhan Nalbantoglu Governmental Hospital and Near East University
Type: Journal Article | Journal: The American journal of tropical medicine and hygiene | Year: 2016

Visceral leishmaniasis (VL) is a vector-borne disease widespread in the Mediterranean basin, including Cyprus. During the last decades no cases were notified from northern Cyprus, but herein three cases of VL (female: 2, male: 1, median age: 24.6 months) diagnosed during their hospital admission between January 2011 and December 2012 are reported. Diagnosis was based on clinical findings; 1 1/64 titer positivity of immunofluorescence antibodies, Leishmania amastigotes in Giemsa-stained slides of bone marrow, as well as molecular identification confirmed that in all three the infecting pathogen was Leishmania infantum Fever, splenomegaly, and hepatomegaly were the typical clinical findings. First-line treatment with liposomal amphotericin B (AmBisome


Ruiz A.,Parasitology Unit | Guedes A.C.,Parasitology Unit | Munoz M.C.,Parasitology Unit | Molina J.M.,Parasitology Unit | And 8 more authors.
Parasitology Research | Year: 2012

Coccidiosis is probably the main parasitic disease affecting goat kids around the weaning period, leading to high economic losses in goat production due to deaths and delayed growth rates of infected animals. A total of 101 kids of 2-4 weeks of age, naturally infected with Eimeria spp., were divided into five groups and studies were conducted to analyse the effects of metaphylactic administration of diclazuril (Vecoxan®) on parasitological and productive parameters. Two different doses of diclazuril (1 and 2 mg/kg BW, p.o.) were given either at 3 weeks (single treatment) or at 3 and 5 weeks of life (double treatment). The faecal oocyst shedding and the body weights of the animals were monitored at 2-weeks intervals for 6 consecutive weeks. Treatments of goat kids with diclazuril were effective against the three most predominant Eimeria species recorded in this study (E. arloingi, E. ninakohlyakimovae and E. christenseni) and also against other minor species found in faecal examinations, including E. alijevi, E. caprina, E. jolchijevi, E. caprovina, E. hirci and E. aspheronica). In consequence, OPG values lower than 1×10 3 were detected in 90 to 100% of the animals up to 15-20 days post-treatment depending on the treatment regimen. Even a single dose of 1 mg/kg BW p.o. resulted in an increase of growth rates in treated animals and therefore should be considered as a control strategy in farms precluding coccidian infections, whilst double and multiple dose treatments could be the recommendation for environments heavily contaminated with Eimeria oocysts. In relation to the OPG reduction and increased growth rates, the severity of the clinical signs (i.e., diarrhoea) was ameliorated in treated animals during the course of infection compared to that of non-treated or control kids. The precise timing of treatment appears crucial in order to prevent severe clinical coccidiosis and thereby enabling the adequate development of protective immune response against Eimeria challenge infections. © Springer-Verlag 2011.


Sadeghi H.,Parasitology Unit | Borji H.,Ferdowsi University of Mashhad
Asian Pacific Journal of Tropical Disease | Year: 2015

Objective: To study the distribution of intestinal parasites in a population in Qazvin city in north of Iran. Methods: A retrospective cross-sectional study of patients with suspicious intestinal parasitic infections referred to the Zakaria Razi Laboratory in Qazvin, north of Iran, was conducted from April 21, 2009 to October 20, 2012. A total of 5 739 stool specimens from 4 053 (70.6%) males and 1 686 (29.3%) females were examined for intestinal parasites using direct wet mounting, formol-ether concentration and modified acid-fast staining techniques. Results: The overall infection rate of intestinal parasite was 5.8% (3.7% in males and 2.1% in females). The distribution of intestinal parasites detected in stool specimens was as follows: 116 (2.0%) Entamoeba coli, 110 (1.9%) Giardia lamblia, 49 (0.85%) Blastocystis hominis, 30 (0.5%) Enodolimax nana, 12 (0.2%) Iodamoeba butschlii, 2 (0.03%) Trichomonas hominis, 9 (0.1%) Hymenolepis nana, 1 (0.01%) Strongyloides stercoralis, 1 (0.01%) Dicrocoelium dendriticum, and 1 (0.01%) Trichuris trichura. Parasites detected in cellophane tape specimens included 5 (0.08%) Enterobius vermicularis. Conclusions: In this regard, findings of this study can be used as a basis to develop strategies and preventive programs for targeting groups at greater risk of intestinal parasitic infections. © 2015 by the Asian Pacific Journal of Tropical Disease.


Mondal D.,Parasitology Unit | Khan M.G.M.,Parasitology Unit
Current Opinion in Infectious Diseases | Year: 2011

Purpose of Review: Post-kala-azar dermal leishmaniasis (PKDL) is a challenge for clinicians and researchers, because its burden is poorly investigated and pathogenesis is disputable. However, recent studies contributed to understanding of the pathogenesis of PKDL especially its association with host immunological factors, and also how to improve its diagnosis and treatment. This review focuses on recent advances in diagnosis, new insights into pathogenesis and case management. Recent Findings: Information regarding the burden of PKDL, especially in Bangladesh, is now available. Association between skin parasite burden and different clinical forms of PKDL has been explored. The diagnostic importance of detection of Leishmania donovani DNA in the peripheral blood buffy coat and in skin specimens by PCR has been studied. Variable effects of different antileishmanial drugs on immune response have been observed. Finally, high efficacy of miltefosine for treatment of PKDL has been demonstrated. Summary: The incidence of PKDL is reducing in India after introduction of miltefosine and amphotericin B for treatment of visceral leishmaniasis. It remains higher in Bangladesh and in Sudan. Parasite burden is higher in nodular and papular forms of PKDL compared to the macular form of the disease. The demonstration of Leishmania DNA in peripheral blood buffy coat and in skin specimens can help to diagnose 40-75% clinically suspected PKDL individuals. An initial cure rate of 95% has been achieved with miltefosine for treatment of PKDL. However, the efficacy of combination therapy should be explored to reduce the treatment duration and hence to improve treatment compliance. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Loading Parasitology Unit collaborators
Loading Parasitology Unit collaborators