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PubMed2000

Screening Congo Red and its analogues for their ability to prevent the formation of PrP-res in scrapie-infected cells.

Transmissible spongiform encephalopathies (TSEs) are incurable, fatal diseases. The dye Congo Red (CR) can cure cells infected with agents of the sheep TSE, scrapie, but is not used as a therapeutic or prophylactic agent in vivo, as its effects are small, possibly due to low blood-brain barrier permeability, and complicated by its intrinsic carcinogenicity. In this paper, the development is described of a structure-activity profile for CR by testing a series of analogues of this dye for their ability to inhibit the formation of the protease-resistant prion protein, PrP-res, a molecular marker for the infectious agent, in the scrapie-infected, SMB cell line. It was found that the central benzidine unit in CR, which gives the molecule potential carcinogenicity, can be replaced by other, less toxic moieties and that the sulphonate groups on the core molecule can be replaced by carboxylic acids, which should improve the brain permeability of these compounds. However, detailed dose-response curves were generated for several derivatives and they revealed that, while some compounds showed inhibition of PrP-res accumulation at high concentrations, at low concentrations they actually stimulated levels of PrP-res above control values.

Animals↗
PubMed1999

Colony morphotypes on Congo red agar segregate along species and drug susceptibility lines in the Mycobacterium avium-intracellulare complex.

Isolates of the Mycobacterium avium-intracellulare complex (MAC) have long been known to segregate into transparent opaque and rough colony morphotypes that differ from each other in clinically important parameters including drug susceptibility and virulence. Here the authors report additional morphotypic variation that occurs on two levels: interspecific (between M. avium and M. intracellulare) and intraspecific (within individual M. avium isolates). Clinical isolates of M. avium grown on Congo red (CR) plates formed red, pink or mixed (red and white) opaque colonies, while M. intracellulare isolates formed purely white opaque colonies. A quantitative CR binding assay showed that this interspecific differential applies to transparent as well as opaque colony variants; however, it was less pronounced among laboratory reference strains than among recent clinical isolates. Opaque colonies of M. avium isolates with 'mixed' phenotypes segregated into stable opaque red and white variants with shared IS1245 banding patterns (intraspecific segregation). White segregants of M. avium were more flocculent and significantly more resistant to ciprofloxacin and rifamycin drugs than were red segregants. Thus, cultivation on CR agar revealed a previously unknown multidrug resistant colony morphotype of M. avium.

Anti-Bacterial Agents↗
PubMed2007

Petrotoga halophila sp. nov., a thermophilic, moderately halophilic, fermentative bacterium isolated from an offshore oil well in Congo.

A novel thermophilic, moderately halophilic, rod-shaped bacterium, strain MET-B(T), with a sheath-like outer structure (toga) was isolated from an offshore oil-producing well in Congo, West Africa. Strain MET-B(T) was a Gram-negative bacterium with the ability to reduce elemental sulfur, but not sulfate, thiosulfate or sulfite into sulfide. The optimum growth conditions were 60 degrees C, pH 6.7-7.2 and 4-6 % NaCl. The DNA G+C content was 34.6 mol%. Strain MET-B(T) was phylogenetically related to members of the genus Petrotoga; Petrotoga miotherma, Petrotoga olearia and Petrotoga mexicana were the closest relatives, with type strains exhibiting more than 99 % identity in an analysis of small-subunit rRNA gene sequences. The values for DNA-DNA relatedness between the type strains of these three species and strain MET-B(T) were less than 42 %. As MET-B(T) was found to be genetically and physiologically different from other species of the genus Petrotoga, this strain is proposed as representing a novel species, for which the name Petrotoga halophila sp. nov. is proposed. The type strain is MET-B(T) (=DSM 16923(T)=CCUG 50214(T)).

Bacterial Typing Techniques↗
PubMed2003

Genetic variability of Crimean-Congo haemorrhagic fever virus in Russia and Central Asia.

Hyalomma marginatum ticks (449 pools, 4787 ticks in total) collected in European Russia and Dermacentor niveus ticks (100 pools, 1100 ticks in total) collected in Kazakhstan were screened by ELISA for the presence of Crimean-Congo haemorrhagic fever virus (CCHFV). Virus antigen was found in 10.2 and 3.0 % of the pools, respectively. RT-PCR was used to recover partial sequences of the CCHFV small (S) genome segment from seven pools of antigen-positive H. marginatum ticks, one pool of D. niveus ticks, four CCFH cases and four laboratory virus strains. Additionally, the entire S genome segments of the CCHFV strains STV/HU29223 (isolated from a patient in European Russia) and TI10145 (isolated from H. asiaticum in Uzbekistan) were amplified, cloned and sequenced. Phylogenetic analysis placed all CCHFV sequences from Russia in a single, well-supported clade (nucleotide sequence diversity up to 3.2 %). Virus sequences from H. marginatum were closely related or identical to those recovered from patients in the same regions of southern Russia. Newly described CCHFV strains from Central Asian countries fell into two genetic lineages. The first lineage was novel and included closely related virus sequences from Kazakhstan and Tajikistan (nucleotide sequence diversity up to 3.2 %). In contrast, a newly described CCHFV strain from Uzbekistan, strain TI10145, clustered on the phylogenetic trees with strains from China.

Animals↗
PubMed2004

Evidence of segment reassortment in Crimean-Congo haemorrhagic fever virus.

The complete nucleotide sequences of the small (S) and medium (M) segments of three independent strains of Crimean-Congo haemorrhagic fever (CCHF) virus isolated in Uzbekistan, Iraq and Pakistan have been determined. Partial S and M segment sequences from two additional strains and partial large segment sequences from five strains of CCHF virus have also been obtained. These data have been compiled and compared with published full-length and partial sequences of other CCHF virus strains. Analysis of virus strains for which complete and partial S and M segment sequences are available reveals that the phylogenetic grouping of some strains differ between these two segments. Data provided in this report suggest that this discrepancy is not the result of recombination, but rather the consequence of reassortment events that have occurred in some virus lineages. Although described in other genera of the Bunyaviridae family, this is the first report of segment reassortment occurring in the Nairovirus genus.

Base Sequence↗
PubMed2005

A novel simian immunodeficiency virus from black mangabey (Lophocebus aterrimus) in the Democratic Republic of Congo.

In order to understand primate lentivirus evolution, characterization of additional simian immunodeficiency virus (SIV) strains is essential. Here, an SIV from a black mangabey (Lophocebus aterrimus) originating from the Democratic Republic of Congo was analysed phylogenetically. The monkey had cross-reactive antibodies against human immunodeficiency virus type 1 (HIV-1) and HIV-2. The viral pol region sequence was amplified by nested PCR and sequence analysis confirmed that it was related to known SIV sequences. This is the first report to characterize genetically an SIV from the monkey genus Lophocebus. Phylogenetic analysis of the pol region revealed that this novel SIV, designated SIVbkm, fell into the SIVsyk and SIVgsn virus group, containing viruses isolated from the genus Cercopithecus, and suggests that cross-species transmission has occurred between species of the genera Lophocebus and Cercopithecus.

Animals↗
PubMed2005

Evidence for recombination in Crimean-Congo hemorrhagic fever virus.

Crimean-Congo hemorrhagic fever (CCHF) virus has attracted considerable attention recently and a number of phylogenetic studies have been published, based mostly on partial sequences of S and M RNA segments. In this study, available full-length S, M and L segment sequences of CCHF virus were checked for recombination. Similarity plots and bootscan analysis of the S segment suggested multiple recombination events between southern European, Asian and African CCHF virus strains, with additional evidence provided by phylogenetic trees, the hidden Markov model and probabilistic divergence measures methods. No unambiguous signs of recombination were observed for M and L segments; however, the results did not exclude the possibility of this. These findings, coupled with a recent report on reassortment in CCHF virus, suggest caution when assessing CCHF virus phylogeny based on short sequence fragments.

Animals↗
PubMed2005

Co-evolutionary patterns of variation in small and large RNA segments of Crimean-Congo hemorrhagic fever virus.

The genus Nairovirus of the family Bunyaviridae includes the Crimean-Congo haemorrhagic fever (CCHF) species group. The species is predominated by the hazard-group 4 pathogens, from which the name and majority of strain entries are derived. Additionally, the species embraces hazard-group 2 viruses that are classified as members by antigenic cross-reactivity. CCHF viruses have a tripartite RNA genome consisting of large (L), medium (M) and small (S) segments. Here, the sequence characterization of previously undescribed L and S segments from novel strains originating in the Middle East and Africa is reported. Further scrutiny of this data with phylogenetic tools, in the context of other publicly available sequence information, reveals analogous grouping patterns between the L and S segments. These groups correlate with the geographical distribution of strain isolation and indicate that the L and S segments of CCHF viruses have evolved together.

Africa↗
PubMed2006

The effects of sodium sulfate, glycosaminoglycans, and Congo red on the structure, stability, and amyloid formation of an immunoglobulin light-chain protein.

Light-chain amyloidosis (AL) is characterized by immunoglobulin light-chain fragments aggregating into amyloid fibrils that deposit extracellularly in vital organs such as the kidney, the heart, and the liver, resulting in tissue degeneration and organ failure, leading to death. Cardiac involvement is found in 50% of AL patients and presents the most severe cases with a life expectancy of less than a year after diagnosis. In this study, we have characterized the variable domain of a cardiac AL patient light chain called AL-09. AL-09 folds as a beta-sheet and is capable of forming amyloid fibrils both in the presence of sodium sulfate and in self-seeded reactions under physiological conditions. Glycosaminoglycans such as dermatan sulfate and heparin promote amyloid formation of self-seeded AL-09 reactions, while the glycosaminoglycan chondroitin sulfate A stabilized oligomeric intermediates and did not elongate the preformed fibrils (nucleus) present in the reaction. Finally, the histological dye Congo red, known to bind to the cross beta-sheet structure of amyloid fibrils, inhibits AL-09 amyloid fibril formation in the presence of sodium sulfate and in self-seeded reactions. This paper provides insight into the impact of different reagents on light-chain stability, structure, amyloid fibril formation, and inhibition.

Amyloid↗
PubMed2003

Mortality, violence and lack of access to healthcare in the Democratic Republic of Congo.

The people of the Democratic Republic of Congo for decades have been living in a situation of chronic crisis. Violence, population displacement and the destruction of infrastructure and health services have devastated the health of the population. In 2001, Médicins Sans Frontières conducted a survey in five areas of western and central DRC to assess mortality, access to health-care, vaccination coverage and exposure to violence. High mortality rates were found in front-line zones, mainly due to malnutrition and infectious diseases. In Basankusu approximately 10 per cent of the total population and 25 per cent of the under-five population had perished in the year before the survey. Humanitarian needs remain acute across the country, particularly near the front line. Infectious-disease control and treatment are a priority, as is increasing access to health-care. Humanitarian assistance must be increased considerably, especially in rural areas and zones that have been affected directly by conflict.

Adult↗
PubMed2006

Democratic Republic of the Congo: undoing government by predation.

This paper draws on two periods of field research, conducted in 2004, to consider the state of governance in the Democratic Republic of the Congo (DRC). The first measures the paralysing impact of illegal taxation on riverine trade in the western provinces; the second documents civilian attempts to seek safety from violence in the troubled east, and evaluates third-party efforts to provide protection and security. Analysis of study findings suggests that the DRC's current governance crisis is neither historically novel nor driven exclusively by mineral resources, extraction rights or trafficking. Rather, government by predation is an endemic and systematic feature of the civil and military administration, ensuring the daily economic survival of soldiers and officials, who are able to wield their authority in a 'riskfree' environment, without oversight or accountability. The paper's conclusion tries to make sense of the persistence of corruption in social and political life, and assess the capacity of ordinary citizens to reverse their predicament.

Democratic Republic of the Congo↗
PubMed1991

Chrysops silacea and C.dimidiata seasonality and loiasis prevalence in the Chaillu mountains, Congo.

Seasonal activity of the loiasis vectors Chrysops dimidiata Wulp and Chrysops silacea Austen (Diptera: Tabanidae) was studied during 1987-89 in villages and surrounding forest of the Chaillu Mountains, Congo. Chrysops were captured mainly in the hot rainy season (November-May) and densities of both species were higher in the forest than in villages. C.silacea predominated at all sites and C.dimidiata was rarely found in villages. In the rain forest, between 07.00 and 18.00 hours, 12 times more C.silacea and 3 times more C.dimidiata were collected with hand-nets (range 15-81 per man-day) than were caught in landing/biting collections on human bait. Chrysops man-biting rates were higher in villages closer to the forest, but variations in loiasis prevalence among villagers (microfilaraemia rates 16-37%) were not proportional to the intensity of contact between people and vectors in the villages, indicating that the majority of loiasis transmission probably occurs when people go into the forest.

Animals↗
PubMed2004

The effectiveness of active population screening and treatment for sleeping sickness control in the Democratic Republic of Congo.

BACKGROUND: The human African trypanosomiasis (HAT) control programme of the Democratic Republic of Congo (DRC) uses mass screening with the card agglutination test for trypanosomes (CATT). We looked at the contribution of CATT and improved parasitological confirmation to the effectiveness of screening and treatment. METHOD: The effectiveness of the screening and treatment process is measured by the percentage of HAT cases that is effectively cured after a single round of screening. The process is analysed in five steps: (i) the attendance at the screening, (ii) the sensitivity of the screening procedure, (iii) the sensitivity of the parasitological confirmation, (iv) the proportion of the confirmed cases that effectively receive treatment and (v) the cure rate of the treatment. We used a simplified model that multiplies proportions of infected persons that go through each step. We estimated these parameters using a combination of routine data collected by the national control programme over the period January 1997 to December 1998 and published data. For varying attendance rates we compared the effectiveness of screening strategies based on CATT or on CATT combined with improved parasitological confirmation by mini anion exchange column technique (mAECT) with the previously used strategy based on palpation of neck glands and microscopy alone. RESULTS: The model shows that overall effectiveness of the active case detection and treatment strategy is <50% under most scenarios. Attendance rates averaged 74% but showed considerable regional variability and are a major problem in some areas of DRC. The CATT and replacing traditional parasitology by mAECT increases the sensitivity of the screening but a substantial part of the gains are lost at other stages of the screening process. CONCLUSION: Improvements of the HAT screening process such as introduction of CATT or mAECT only make sense if other parameters and attendance rate in particular are optimized at the same time.

Agglutination Tests↗
PubMed2006

Artesunate + amodiaquine and artesunate + sulphadoxine-pyrimethamine for treatment of uncomplicated malaria in Democratic Republic of Congo: a clinical trial with determination of sulphadoxine and pyrimethamine-resistant haplotypes.

We undertook a trial of artesunate + amodiaquine (AS + AQ) and artesunate + sulphadoxine-pyrimethamine (AS + SP) in 180 children of age 6-59 months with uncomplicated malaria in Democratic Republic of Congo. Children were randomly allocated to receive 3 days observed treatment of AS + AQ (n = 90) or 3 days of AS + SP (n = 90). Primary efficacy outcomes were 28-day parasite recurrence rates, and recrudescence rates were adjusted by genotyping to distinguish new infection and recrudescence. In addition, we determined the prevalence of molecular markers of resistance to sulphadoxine and pyrimethamine. Day 28 parasite recurrence rates were 16.9% (14/83; 95% CI: 9.5-26.7) in the AS + AQ group and 34.6% (28/81; 95% CI: 24.3-46.0) in the AS + SP group (P = 0.009). After PCR correction, recrudescence rates were 6.7% (5/74; 95% CI: 2.2-15.1) for AS + AQ and 19.7% (13/66; 95% CI: 10.9-31.3) for AS + SP (P = 0.02). There was no significant difference between the two arms in time to parasite clearance, fever clearance and gametocyte clearance. Parasite genotyping showed high frequencies of dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) molecular SP-resistance markers, with 57% of the samples showing more than three mutations linked to SP resistance, and 27% with triple-dhfr/double-dhps haplotype, confirming that SP treatment failure rates are likely to be high. AS + AQ had significantly higher efficacy than AS + SP. These results contributed to the subsequent change to AS + AQ as first-line regimen in the country. Efforts to properly implement the new protocol and maintain adherence at acceptable levels should include health staff and patient sensitization. The 6.8% recrudescence rate indicates that AS + AQ should be monitored closely until a more effective artemisinin combination therapy regimen is needed and can be introduced.

Amodiaquine↗
PubMed2007

Quality control of active ingredients in artemisinin-derivative antimalarials within Kenya and DR Congo.

OBJECTIVES: Artemisinin-derivative drugs are widely used to treat Plasmodium falciparum malaria and very few studies have investigated the quality of these medicines in Africa. We analysed the active ingredient contents of artemisinin-derivative drugs marketed in Kenya and DR Congo. METHODS: We analysed tablets, capsules, dry suspensions and injections (IM) containing either artemether (AM), arteether (AE), artesunate (ARS) or dihydroartemisinin (DHA). The content of active ingredients and preservatives was determined quantitatively using validated HPLC-UV methods. All analyses were done according to European pharmacopoeia requirements. RESULTS: Labelled active ingredients were identified in all samples, however with varying dosages. Nine of the 24 drug samples analysed did not comply with the pharmacopoeial requirements of 95-105%: seven samples were underdosed and two were slightly overdosed. DHA was the active ingredient in 57% of the underdosed samples. AE injections had the lowest drug content (77%). Two-thirds of the dry powder suspensions were either substandard or fake. Tablets were up to 23% out of range. Unidentified peaks were observed on the chromatograms of AE IM injections and a DHA dry powder. CONCLUSIONS: Counterfeit or substandard artemisinin-derivative drugs are being sold in parts of Africa, presenting a potential route for resistance development in the future. Appropriate measures need to be taken to maintain proper and safe use of these medicines.

Antimalarials↗
PubMed2006

Analysis of risk-factors among patients with Crimean-Congo haemorrhagic fever virus infection: severity criteria revisited.

The aim of this study was to determine the predictors of mortality among patients infected with Crimean-Congo haemorrhagic fever (CCHF) virus. Among patients with acute febrile syndrome, characterised by malaise, bleeding, leukopenia and thrombocytopenia, who were admitted to hospital during the spring and summer of 2002-2004, 54 had positive IgM and/or PCR results for CCHF virus in blood or tissue. The overall case fatality rate was 7.4%. Among the fatalities, haematemesis (p 0.009), melaena (p 0.001) and somnolence (p 0.022) were more common, the median platelet count was significantly lower (10,600/mL vs. 20,000/mL; p 0.038), the mean prothrombin time (27 s vs. 16 s; p 0.002) and mean activated partial thromboplastin time (73 s vs. 44 s; p < 0.001) were longer, and the mean alanine transferase (ALT) level (1,125 vs. 331; p < 0.001), the mean aspartate transferase (AST) level (3,118 vs. 913; p 0.004) and the mean fibrinogen level (119 vs. 340; p 0.012) were higher. Serum IgM and IgG against CCHF virus was detected in 25% and 0%, respectively, of fatal cases, compared with 94% and 62%, respectively, of cases with favourable outcomes. Oral ribavirin was prescribed to 22 (41%) patients. Of the four fatal cases, it was the intention to prescribe ribavirin to three patients, but this was not possible because of haematemesis and melaena. Higher levels of AST (>or= 700 U/L) and ALT (>or= 900 U/L) are suggested for use as severity criteria. Oral ribavirin was not effective for patients with haematemesis, and intravenous ribavirin is necessary for treatment of CCHF.

Adult↗
PubMed1990

Use of a modified cupric acetate method for the detection and quantitation of xylanolytic activities: a comparative study with the congo red method.

A modified cupric acetate method for the screening and quantitation of xylanolytic activities was comparable with the more widely used congo red method with respect to sensitivity and ease of use and was shown to have points of merit over the latter. The use of a non-linear correction, in comparison to the conventional linear one, for the effect of dilution on the quantitative plate assay was evaluated.

Bacillus↗
PubMed2006

Species protection, the changing informal economy, and the politics of access to the bushmeat trade in the Democratic Republic of Congo.

Our understanding of the linkages between the bushmeat trade and the wider informal economy is limited. This lack of knowledge is particularly problematic for conservation under conditions of political instability, when the informal economy can be highly dynamic and impacts on wildlife populations can be severe. To explore these interlinked processes, we conducted a study of the bushmeat trade in Garamba National Park, Democratic Republic of Congo, through a combination of market surveys, semistructured interviews, and direct observation. We focused on the sale of protected and unprotected species in urban and rural markets, and the bushmeat commodity chains that supplied these markets, under conditions of political stability and armed conflict. During peacetime, protected species from the park (predominantly elephant and buffalo) rarely appeared in the rural markets, but they comprised more than half of all bushmeat sales in the urban markets. This pattern reflected differences in the rural and urban commodity chains. Automatic weapons were urban trade. The use of such weapons was discouraged by the traditional chiefs, who administered the village markets. During wartime, the sales of protected species in the urban markets increased fivefold because the military officers fled, leaving behind an open-access system that led to a massive increase in the exploitation of protected species. In contrast, the rural markets remained relatively stable because of the continued authority of the village chiefs. Our results indicate that sociopolitical factors can be an important determinant of species offtake and, therefore, that knowledge of the bushmeat commodity chain can be vital to controlling theprocesses that drive species extraction. In addition, our findings suggest that traditional authorities can be potentially valuable partners for bushmeat management.

Animals↗