6320 research outputs found
Sort by
Antiviral compounds show enhanced activity in HIV-1 single cycle pseudovirus assays as compared to classical PBMC assays
No full textHIV-1 Env pseudotyped viruses (PV) are an attractive tool for studying the antiviral activities of compounds interfering with virus entry into a target cell. To investigate whether results obtained in PV assays are relevant biologically, the antiviral activity of 6 reference compounds was compared on 5 virus isolates of different clades using three assays: (1) replicating virus in peripheral blood mononuclear cells (PBMCs), (2) PV in CD4 and CCR5- or CXCR4 co-receptor expressing Ghost cells, and (3) PV in PBMCs. A significant linear relationship was found between both single-cycle PV assays (P<0.0001, R2=0.75). Moreover, both assays showed enhanced sensitivity to the antiretrovirals tested (P=0.013 and 0.015, respectively) as compared to the PBMC assay with replication-competent virus. Most importantly, results from the latter assay could be predicted significantly from both PV assays, in which either Ghost target cells (P<0.0001, R2=0.61) or PBMCs (P<0.0001, R2=0.55) were used. The usefulness of the PV assay was demonstrated further by investigating the impact of the HIV-1 Env subtype on the antiviral activity of five new compounds derived from the entry inhibitor BMS806
Assessment of the occurrence of trypanocidal drug resistance in trypanosomes of naturally infected cattle in the Adamaoua region of Cameroon using the standard mouse test and molecular tools
No full textFrom May to November 2005, a study was carried out to assess the occurrence of trypanocidal drug resistance (DR) in trypanosomes of naturally infected cattle of the Adamaoua region of Cameroon. Two distinct Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) procedures were used together with an Allele specific-PCR (AS-PCR) and the standardized single-dose mouse test. Using the mouse test, 3 of the 13 Trypanosoma brucei isolates and all 14 tested Trypanosoma congolense isolates were resistant to ISM. However, only 11 of the 25 T. congolense isolates were diagnosed as resistant to ISM using the MboII-PCR-RFLP. Resistance to DA was identified in 1 of the 13 T. brucei isolates and all 11 T. congolense isolates which were tested with the mouse test. Using the AS-PCR or BclI-PCR-RFLP, 3 of the 13 T. brucei isolates and all 25 T. congolense isolates respectively were found resistant. The data presented in this study prove that DR is widespread in the Adamaoua Department of Cameroon. The problem appears to be more serious in T. congolense than in T. brucei. Appropriate measures need to be taken in order to control bovine trypanosomosis in this area
Chile's neoliberal health reform: an assessment and a critique
No full textSummary Points:
The Chilean health system underwent a drastic neoliberal reform in the 1980s, with the creation of a dual system: public and private health insurance and public and private provision of health services.
This reform served as a model for later World Bank–inspired reforms in countries like Colombia.
The private part of the Chilean health system, including private insurers and private providers, is highly inefficient and has decreased solidarity between rich and poor, sick and healthy, and young and old.
In spite of serious underfinancing during the Pinochet years, the public health component remains the backbone of the system and is responsible for the good health status of the Chilean population.
The Chilean health reform has lessons for other countries in Latin America and elsewhere: privatisation of health insurance services may not have the expected results according to neoliberal doctrine. On the contrary, it may increase unfairness in financing and inequitable access to quality care
Bionomics, taxonomy, and distribution of the major malaria vector taxa of {Anopheles} subgenus Cellia in Southeast Asia: an updated review
No full textThere is high diversity of Anopheles mosquitoes in Southeast Asia and the main vectors of malaria belong to complexes or groups of species that are difficult or impossible to distinguish due to overlapping morphological characteristics. Recent advances in molecular systematics have provided simple and reliable methods for unambiguous species identification. This review summarizes the latest information on the seven taxonomic groups that include principal malaria vectors in Southeast Asia, i.e. the Minimus, Fluviatilis, Culicifacies, Dirus, Leucosphyrus, and Sundaicus Complexes, and the Maculatus Group. Main issues still to be resolved are highlighted. The growing knowledge on malaria vectors in Southeast Asia has implications for vector control programs, the success of which is highly dependant on precise information about the biology and behavior of the vector species. Acquisition of this information, and consequently the application of appropriate, sustainable control measures, depends on our ability to accurately identify the specific vectors
High failure rates of melarsoprol for sleeping sickness, Democratic Republic of Congo
No full textA retrospective chart review of 4,925 human African trypanosomiasis patients treated with melarsoprol in 2001-2003 in Equateur Nord Province of the Democratic Republic of Congo showed a treatment failure rate of 19.5%. This rate increased over the 3 years. Relapse rates were highest in the central part of the province
Bulk staining of smears: no demonstrated risk of bacilli transfer from a positive to a negative smear
No full textDespite a theoretical risk of transfer of bacilli from a positive to a negative smear, bulk staining is routinely performed in many laboratories. To assess this risk in our laboratory, two smears were made from each sputum specimen and stained with auramine: one smear was stained on a rack and the second using the bulk method. Smears were read blind using a fluorescence microscope. A total of 811 sputum specimens were analysed. No acid-fast bacilli transfer was observed even when staining solution jars had not been renewed for 3 days. Bulk staining is rapid and cheap, and could be used in laboratories with a high workload in low-resource settings
The efficacy of indoor CDC light traps for collecting the sandfly Phlebotomus argentipes, vector of Leishmania donovani
No full textThe efficacy of light traps for collecting sandflies (Diptera: Psychodidae) varies both inter-specifically and intra-specifically (by gender and physiological status) as a result of significant differences in phototropic and other behavioural characteristics. The efficacy of miniature CDC light traps for collecting Phlebotomus argentipes Annandale & Brunetti, a vector of Leishmania donovani Laveran & Mesnil (Kinetoplastida: Trypanosomatidae), was assessed in the Indian state of Bihar. Sandflies were collected during the night from 16 houses in each of three villages over 3 months (four times at fortnightly intervals) using CDC light traps indoors, and by aspirator collection (carried out by one person for 30 min/house) from the walls of the same houses the following morning. Incidence rate ratios (IRRs) between CDC light trap collections and aspirator collections were obtained through a negative binomial regression with household as random effect. CDC light traps were especially effective in catching males (IRR 3.08, 95% confidence interval [CI] 2.12-4.46) and unfed females (IRR 3.50, 95% CI 2.37-5.16) of P. argentipes, and to a lesser extent gravids (IRR 1.77, 95% CI 1.07-2.93). However, only a relatively small proportion of all blood-fed P. argentipes were collected by light trap (IRR 0.45, 95% CI 0.28-0.73). Despite its limitations in collecting blood-fed female sandflies, the CDC light trap appears to trap a sufficient proportion of the indoor population of sandflies for sampling purposes, and as this light trap is also more convenient and more easily standardized than the aspirator method, we conclude that it is the most efficient method for monitoring P. argentipes populations in the Indian subcontinent
Prevalence of Taenisolium cysticercosis in swine from community-based study in 21 villages of the Eastern Cape Province, South Africa
No full textThe pork tapeworm, Taenia solium, causative organism of porcine cysticercosis and human neurocysticercosis is known to occur in areas of South Africa including Eastern Cape Province but, despite increasing reports of its occurrence throughout the subregion, the prevalence is yet to be clearly established. The parasite presents a potentially serious agricultural problem and public health risk in endemic areas. The human populations considered to be at highest risk of infection with this zoonotic helminth are people living in rural areas most of whom earn their livelihood wholly or partially through livestock rearing. Here we report on initial results of a community-based study of pigs owned by resource-poor, emerging pig producers from 21 villages in the Eastern Cape Province. Lingual examination (tongue palpation) in live pigs, two enzyme-linked immunosorbent assays (ELISAs), which detect parasite antigen (B158/B60 Ag-ELISA and HP10 Ag-ELISA) and an enzyme immunotransfer blot (EITB) assay, which detects antiparasite antibody, were used to verify endemicity and estimate apparent prevalence. In the absence of a gold standard true prevalence was obtained, using a Bayesian approach, with a model that uses both available data and prior information. Results indicate that the parasite is indeed present in the study villages and that true prevalence was 64.6%. The apparent prevalences as measured by each of the four tests were: 11.9% for lingual examination, 54.8% for B158/B60 Ag-ELISA, 40.6% for HP10 Ag-ELISA and 33.3% for EITB. This base-line knowledge of the prevalence of T. solium in pigs provides information essential to the design and monitoring of sustainable and appropriate interventions for cysticercosis prevention and control
Novel markers for treatment outcome in late-stage Trypanosoma brucei gambiense trypanosomiasis
No full textBACKGROUND: To date, no biological marker for treatment outcome in human African trypanosomiasis (HAT) has been described. The accuracy of biological markers for prediction of treatment outcome of HAT caused by Trypanosoma brucei gambiense was assessed. METHODS: Cerebrospinal fluid (CSF) white blood cell (WBC) count and immunoglobulin M (IgM), trypanosome-specific antibody, total protein, and interleukin-10 levels were determined before and up to 24 months after treatment of late-stage HAT. RESULTS: Treatment failure was experienced by 48 of 260 patients. Pretreatment CSF WBC counts > or = 102 cells/microL, IL-10 concentrations > or = 37 pg/mL, LATEX/IgM end titers > or = 1:32, LATEX/T. b. gambiense end titers > or = 1:2, and protein concentrations > or = 674 mg/L were associated with treatment failure. Six months after treatment, patients with CSF WBC counts 0.93). After 12 months, the combination of CSF WBC count > or = 8 cells/microL and LATEX/IgM end titer > or = 1:4 predicted treatment failure with 97% specificity and 79% sensitivity. Eighteen months after treatment, each marker accurately predicted treatment outcome. The combination of CSF WBC count > or = 8 cells/microL and LATEX/IgM end titer > or = 1:4 was 100% specific for treatment failure after 18 and 24 months. CONCLUSIONS: HAT-affected patients with elevated pretreatment CSF levels of WBC, interleukin-10, IgM, trypanosome-specific antibody, and total protein are at risk of treatment failure. Six months after treatment, patients with CSF WBC counts < or = 5 cells/microL can be considered to be cured. The assessment of a combination of CSF WBC count and LATEX/IgM level allowed accurate prediction of outcome beginning at 12 months after treatment, as did each individual marker at 18 months after treatment
Orientation of bovine CTL responses towards PIM, an antibody-inducing surface molecule of Theileria parva, by DNA subunit immunization
No full textEast Coast fever, an acute lymphoproliferative disease of cattle, is caused by the apicomplexan parasite Theileria parva. Protective immunity is mediated by CD8+ cytotoxic T lymphocytes directed against schizont-infected cells. The polymorphic immunodominant molecule, although an antibody-inducing surface molecule of the schizont, has been hypothesized to play a role in protective immunity. In order to evaluate the immunogenicity of PIM for inducing CTL, cattle were immunized with PIM in isolation from other T. parva antigens, forcing the presentation of PIM-derived epitopes on the MHC class I molecules. Although parasite-specific cytotoxicity was induced in both vaccinated animals, their immune response was clearly different. One animal generated MHC-restricted parasite-specific CTL against PIM while the other calf exhibited a strong PIM-specific proliferative response but non-MHC-restricted parasite-specific cytotoxicity. Only calf 1 survived a lethal sporozoite challenge. This DNA immunization technique with an antigen in isolation of CTL-immunodominant antigens might open possibilities for directing CTL responses against predefined antigens, such as strain cross-reacting CTL antigens