6320 research outputs found
Sort by
The invariant surface glycoprotein ISG75 gene family consists of two main groups in the Trypanozoon subgenus
No full textIn Trypanosoma brucei brucei, an invariant surface glycoprotein of molecular weight 75 kDa (ISG75) is uniformly distributed over the surface of a trypanosome and is specific for bloodstream-form parasites. For the other taxa of the Trypanozoon subgenus no data about this surface molecule are available. Therefore, we investigated the ISG75 in the genomes of several pathogenic Trypanozoon by Southern blot, PCR and RT-PCR and sequence analysis. This study reveals that (i) all members of the Trypanozoon subgenus, i.e. T. b. brucei, T. b. gambiense, T. b. rhodesiense, T. evansi and T. equiperdum, harbour ISG75 as multiple gene copies with at least 4-16 copies per genome; (ii) ISG75 gDNA and cDNA sequences are distributed in 2 groups that share at least 75% and 77% identity respectively; (iii) sequences from both groups are transcribed in all species and subspecies of the Trypanozoon subgenus; (iv) the main differences between group I and group II are located in the variable region at the amino-terminus of the putative proteins; (v) however, all the sequences in both groups have some well-conserved features, such as the cysteine residues, an amino-terminal cleavable signal peptide, a single alpha-helix transmembrane domain and a cytoplasmic domain at the carboxy-terminus
The challenge of diagnosing atopic diseases: outcomes in Cuban children depend on definition and methodology
No full textBACKGROUND: Prevalences of childhood asthma and other atopic diseases are increasing worldwide, and so is the number of diagnostic methods and definitions used. We determined the occurrence of atopic diseases in Cuban children with a range of diagnostic approaches commonly used or proposed in epidemiological studies, and compared the different outcome measures. METHODS: A total of 398 Cuban schoolchildren between 5 and 13 years of age were diagnosed by International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, clinical examination, pre- and post-exercise spirometry, and skin prick testing. All results were considered separately, as well as jointly by using scores and definitions as described in the literature. RESULTS: Using questionnaire-based approaches, 21-39% of the children were positive for asthma, 9-19% for atopic dermatitis, and 15-46% for rhinoconjunctivitis. With spirometry, 7% of the children had asthma. Definitions based on a combination of questionnaire and spirometry results yielded asthma rates of 5%. Of all children, 6% wheezed on clinical examination, and only one child showed clinical signs of atopic dermatitis. Eleven percent of the children had a positive skin prick test. In total, 254 children (64%) had an atopic disease as based on the ISAAC questionnaire, and 263 (66%) based on all approaches used. CONCLUSION: Diagnostic outcomes on atopic diseases vary considerably depending on definition and methodology. Our results clearly demonstrate the need for consensus on diagnosing asthma and other atopic diseases in epidemiological studies. Based on the most commonly used ISAAC questionnaire, our data suggest prevalences of atopic diseases in Cuban children that rival those found in some other Latin American countries and developed nations with the highest prevalences in the world
Assessment of routine inspection methods for porcine cysticercosis in Zambian village pigs
No full textThe value of tongue and meat inspection as diagnostic tools for porcine cysticercosis was assessed in 65 Zambian village pigs by comparing the results with carcass dissections. In addition, the intensity of infections, distribution and viability of cysts in infected pigs were measured. Five pigs (7.7%) were positive on tongue examination, while routine meat inspection showed 12 (18.5%) positives. However, carcass dissections detected cysticerci in 31 (47.7%) pigs. The range in number of cysticerci was 1 to 14,662 per carcass. Cysticerci were distributed throughout the carcass with the highest concentration in the heart, tongue and hind legs. In one animal 13 viable cysts were detected only in the brain. Fourteen pigs had more than 100 viable cysts, six between 2 and 100, and four had single cyst infections. Seven animals harboured only calcified cysts. These findings demonstrate the serious shortcomings of routine detection methods for porcine cysticercosis. While the specificity of tongue palpation and meat inspection was 100%, these tests failed to detect the infection in 83.9% and 61.3% of infected pigs, respectively
Taeniasis-cysticercosis in southern Ecuador: assessment of infection status using multiple laboratory diagnostic tools
No full textTaenia solium-taeniasis and cysticercosis were studied in the human and porcine populations of a rural community in the Southern Ecuadorian Andes. From the 1059 inhabitants, 800 serum samples and 958 stool samples could be collected. In addition, 646 from the estimated 1148 pigs were tongue inspected. Circulating antigen was detected by enzyme linked immunosorbent assay (Ag-ELISA) in 2.25% of the human population, whereas intestinal taeniasis was detected in 1.46% by the formalin-ether technique. Following treatment and recovery of tapeworm fragments these were all identified as T. solium. Porcine cysticercosis was diagnosed in 3.56% of the pigs by tongue inspection. In addition, enzyme linked immunoelectrotransfer blot (EITB) was performed on a subset group of 100 humans to confirm the results of the Ag-ELISA. One hundred serum samples from pigs were also analysed by EITB. It appeared that 43 and 74% of humans and pigs had antibodies against T. solium cysticerci, respectively. It is concluded that contrary to the high exposure of the human population to T. solium that is suggested by EITB, the number of active cysticercosis cases, diagnosed by Ag-ELISA, was low, which may indicate endemic stability. The further use of complementary diagnostic methods for a better understanding of the epidemiology of T. solium is suggested
Pathways of Mycobacterium ulcerans infection: a review
No full textBuruli ulcer (BU), an often-deforming skin ulceration caused by Mycobacterium ulcerans (MU), is now considered by the World Health Organization to be the third most common mycobacterium infection. However, the reservoir of MU in the environment and the epidemiology of BU are poorly understood. The disease is prevalent in riverine, slow-flowing and swampy areas of several tropical and subtropical regions of the world, especially in West Africa where the disease is rapidly increasing in incidence. This paper presents a review of published literature concerning epidemiology of, transmission and susceptibility to MU infection. It considers several endemic natural environments and their influence on infection
Transmission of simian immunodeficiency virus SIVcpz and the evolution of infection in the presence and absence of concurrent human immunodeficency virus type 1 infection in chimpanzees
No full textCurrent data suggest that the human immunodeficiency virus type 1 (HIV-1) epidemic arose by transmission of simian immunodeficiency virus (SIV) SIVcpz from a subspecies of common chimpanzees (Pan troglodytes troglodytes) to humans. SIVcpz of chimpanzees is itself a molecular chimera of SIVs from two or more different monkey species, suggesting that recombination was made possible by coinfection of one individual animal with different lentiviruses. However, very little is known about SIVcpz transmission and the susceptibility to lentivirus coinfection of its natural host, the chimpanzee. Here, it is revealed that either infected plasma or peripheral blood mononuclear cells readily confer infection when exposure occurs by the intravenous or mucosal route. Importantly, the presence of preexisting HIV-1 infection did not modify the kinetics of SIVcpz infection once it was established by different routes. Although humoral responses appeared as early as 4 weeks postinfection, neutralization to SIVcpz-ANT varied markedly between animals. Analysis of the SIVcpz env sequence over time revealed the emergence of genetic viral variants and persistent SIVcpz RNA levels of between 10(4) and 10(5) copies/ml plasma regardless of the presence or absence of concurrent HIV-1 infection. These unique data provide important insight into possible routes of transmission, the kinetics of acute SIVcpz infection, and how readily coinfection with SIVcpz and other lentiviruses may be established as necessary preconditions for potential recombination
Evaluation of a rapid culture method for tuberculosis diagnosis; a Latin American multi-center study
No full textSETTINGS: Tuberculosis (TB) diagnostic laboratories in Latin America. OBJECTIVES: Evaluation of thin-layer agar (TLA) compared to Löwenstein-Jensen (LJ) culture for the diagnosis of TB. DESIGN: Phase II prospective study in six laboratories. Samples included sputum and extra-pulmonary specimens from patients with a clinical diagnosis of TB. Respiratory samples were decontaminated using NaOH/ NALC; all samples were centrifuged, stained with Ziehl-Neelsen for acid-fast bacilli (AFB), cultured on LJ and TLA and identified according to recommended procedures. Sensitivity and likelihood ratios (LR), growth detection time and contamination rate were calculated for both media. RESULTS: A total of 1118 clinical specimens were studied. Cultures detected Mycobacterium tuberculosis in all AFB-positive samples, whereas for AFB-negative specimens LJ detected 3.2% and TLA 4.4%. Sensitivity was 92.6% (95%CI 87.9-95.9) and 84.7% (95%CI 78.8-89.0) for TLA and LJ, respectively. Positive and negative LRs were similar. Contamination was 5.1% for TLA and 3.0% for LJ. Median time to detection of a positive culture was 11.5 days (95%CI 9.3-15.0) for TLA and 30.5 days (95%CI 26.9-39.0) for LJ (P < 0.0001). CONCLUSION: Difference in the characteristics of the participating laboratories, the disease prevalence and the number and type of specimens processed did not affect the overall performance of TLA as compared to LJ, supporting the robustness of the method and its feasibility in different laboratory settings