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Susan C Welburn

Publications and source records attributed to Susan C Welburn.

10 recordsLinked to original sources
PubMed2006

Death of a trypanosome: a selfish altruism.

African trypanosomes and some related parasitic protozoa are affected by a form of programmed cell death (PCD) that shows typical hallmarks of apoptosis. Although it has been speculated that PCD has a function in life-cycle progression and the struggle for survival of these parasites, no satisfactory model has yet been proposed for the molecular mechanism(s) of PCD in protozoa, raising questions about its physiological relevance in these organisms. As we discuss here, the most important point that needs to be addressed is whether a single-celled organism can undertake a process that is considered altruistic.

Animals↗
PubMed2006

Crisis, what crisis? Control of Rhodesian sleeping sickness.

There is an urgent need for cost-effective strategies for the sustainable control of Trypanosoma brucei rhodesiense (Rhodesian) sleeping sickness, which is a fatal zoonotic disease that has caused devastating epidemics during the past century. Sleeping sickness continues to be controlled by crisis management, using active case detection, treatment and vector control - activities that occur only during major epidemics; during the intervening periods, farmers and communities must fend for themselves. There are several methods for assessing the burden of this disease and there is a series of farmer-led methodologies that can be applied to reduce the burden of human and animal trypanosomiases.

Animal Husbandry↗
PubMed2005

Sleeping sickness in Uganda: a thin line between two fatal diseases.

OBJECTIVE: To determine, through the use of molecular diagnostic tools, whether the two species of parasite that cause human African trypanosomiasis have become sympatric. DESIGN: Blood sampling of all available patients between June 2001 and June 2005 in central Uganda and between July and September 2003 in northwest Uganda and analysis of subcounty sleeping sickness records in Uganda between 1985 and 2005. SETTING: Sleeping sickness treatment centres in central and northwest Uganda and in south Sudan. PARTICIPANTS: Patients presenting at the treatment centres and diagnosed as having sleeping sickness. MAIN OUTCOME MEASURE: Classification of parasites from patients from each disease focus as either Trypanosoma brucei rhodesiense (acute form) or T b gambiense (chronic form). RESULTS: Blood from 231 patients with sleeping sickness in central Uganda and from 91 patients with sleeping sickness in northwest Uganda and south Sudan were screened for T b rhodesiense (detection of SRA gene) and T b gambiense (detection of TgsGP gene). All samples from central Uganda were classified as T b rhodesiense, and all samples from northwest Uganda and south Sudan were identified as T b gambiense. CONCLUSIONS: The two focuses of human African trypanosomiasis remain discrete, but the area of Uganda affected by the acute form of human sleeping sickness has increased 2.5-fold since 1985, spreading to three new districts within the past five years through movement of infected livestock. Without preventive action targeted at the livestock reservoir of this zoonotic disease, it is likely that the two disease focuses will converge. This will have a major impact on diagnosis and treatment of this neglected disease. Real time monitoring is recommended, using molecular diagnostic tools (at a regional surveillance centre, for example) targeted at both livestock and human patients.

Animals↗
PubMed2005

Using remote sensing and geographic information systems to identify villages at high risk for rhodesiense sleeping sickness in Uganda.

Geographic information systems (GIS) and remote sensing were used to identify villages at high risk for sleeping sickness, as defined by reported incidence. Landsat Enhanced Thematic Mapper (ETM) satellite data were classified to obtain a map of land cover, and the Normalised Difference Vegetation Index (NDVI) and Landsat band 5 were derived as unclassified measures of vegetation density and soil moisture, respectively. GIS functions were used to determine the areas of land cover types and mean NDVI and band 5 values within 1.5 km radii of 389 villages where sleeping sickness incidence had been estimated. Analysis using backward binary logistic regression found proximity to swampland and low population density to be predictive of reported sleeping sickness presence, with distance to the sleeping sickness hospital as an important confounding variable. These findings demonstrate the potential of remote sensing and GIS to characterize village-level risk of sleeping sickness in endemic regions.

Animals↗
PubMed2005

The rapid isolation and growth dynamics of the tsetse symbiont Sodalis glossinidius.

Sodalis glossinidius is known exclusively in endosymbiosis with tsetse flies (Genus: Glossina) and is one of the few insect bacterial symbionts that have been successfully cultured in vitro. This study details improved isolation and solid culture protocols that allow for a standardised and rapid preparation/maintenance of clonal material from individual flies. The isolation and culture of S. glossinidius was confirmed by partial sequencing of the 16S rDNA gene and specific PCR. In addition, the growth dynamics and changes in cell viability during liquid culture are described. The potential for culture of other endosymbiont taxa is discussed.

Aedes↗
PubMed2003

Cattle owners' perceptions of African bovine trypanosomiasis and its control in Busia and Kwale Districts of Kenya.

A study using a structured questionnaire was conducted in Busia District, Western Kenya and Kwale District, Coastal Kenya to obtain qualitative and quantitative information from 256 cattle owners about their production systems, their perceptions of the diseases encountered in their cattle, the drugs used, and other measures adopted to control trypanosomiasis in cattle. The predominant production system was mixed crop-livestock with farmers owning 2-11 local cattle on holdings between 2 and 5 ha. Approximately 15% of disease episodes in cattle were perceived to be trypanosomiasis, although the farmers' ability to make diagnoses was limited in that over half of the diagnoses were inconsistent with the clinical signs described. Drugs were generally obtained from agro-veterinary shops, and the farmers themselves administered slightly more than half of these. One third of drug treatments given to sick cattle were trypanocides, but over half of these trypanocidal treatments were given to cattle believed to have diseases other than trypanosomiasis.

Agriculture↗
PubMed2002

Characterisation of the QM gene of Trypanosoma brucei.

The QM protein has been reported to have roles in both tumour suppression and transcription factor regulation in vertebrate cells, and in ribosome stability in both yeast and mammals. The present study isolated the QM gene of Trypanosoma brucei and determined its sequence. Alignment with QM sequences from Saccharomyces cerevisiae, Arabidopsis thaliana, Drosophila melanogaster and Homo sapiens revealed greater than 60% identity. Southern blot analysis revealed multiple copies of QM within the trypanosome genome. An epitope tag was inserted into the C-terminus of the T. brucei QM and the protein expressed under inducible control in procyclic form trypanosomes. Immune fluorescence microscopy revealed co-localisation with the GPI:protein transamidase component, GPI8, a distribution indicative of ribosome association with the rough endoplasmic reticulum.

Amino Acid Sequence↗
PubMed2002

Recent developments in human African trypanosomiasis.

PURPOSE OF REVIEW: Sleeping sickness has re-emerged as a serious problem in sub-Saharan Africa, with an estimated 100000 deaths each year. South Sudan, the Democratic Republic of Congo and Angola have experienced serious epidemics of the Gambian form of the disease. The control of Gambian sleeping sickness, which relies primarily on active case finding followed by chemotherapy, is being threatened by problems of drug resistance. Recently, Rhodesian sleeping sickness has also posed a health risk to travellers visiting game parks in East Africa. RECENT FINDINGS: Because of war-related constraints, which have prevented case detection, the prevalence of Gambian sleeping sickness commonly exceeds 5% and reached 29% in one focus in south Sudan. The incidence of Gambian infections refractory to melarsoprol treatment has also risen sharply in northern Uganda, northern Angola and southern Sudan, with failure rates as high as 26.9%. Molecular techniques based on the gene for human serum resistance (SRA) have enabled the identification of human infective parasites in the domestic animal reservoir. This molecular tool has shown that the Rhodesian form of the disease is being carried in cattle northwards in Uganda towards areas endemic for the Gambian form. The coalescence of distributions of the chronic and acute forms of the disease will present problems for both control and treatment. SUMMARY: This review surveys the molecular tools that are improving our understanding of the epidemiology of sleeping sickness, and highlights the search for new diagnostics and drugs to deal with the disease.

Africa South of the Sahara↗