9 research outputs found
Biopsy case mix and diagnostic yield at a Malawian central hospital
Cancer is a major disease burden worldwide resulting in high morbidity and mortality. It is the leading cause of mortality in developed countries and is one of the three leading causes of death for adults in developing countries. Pathological examination of tissue biopsies with histological confirmation of a correct cancer diagnosis is central to cancer care. Without an accurate and specific pathologic diagnosis, effective treatment cannot be planned or delivered. In addition, there are marked geographical variations in incidence of cancer overall, and of the specific cancers seen. Much of the published literature on cancer incidence in developing countries reflects gross estimates and may not reflect reality. Performing baseline studies to understand these distributions lays the groundwork for further research in this area of cancer epidemiology. Our current study surveys and ranks cancer diagnoses by individual anatomical site at Queen Elizabeth Central Hospital (QECH) which is the largest teaching and referral hospital in Malawi. A retrospective study was conducted reviewing available pathology reports over a period of one full year from January 2010 to December 2010 for biopsies from patients suspected clinically of having cancer. There were 544 biopsies of suspected cancer, taken from 96 anatomical sites. The oesophagus was the most common biopsied site followed by breast, bladder, bone, prostate, bowel, and cervical lymph node. Malignancies were found in biopsies of the oesophagus biopsies (squamous cell carcinoma, 65.1%; adenocarcinoma, 11.6%), breast (57.5%), bladder (squamous cell carcinoma, 53.1%) and stomach (37.6%). Our study demonstrates that the yield of biopsy for clinically suspected malignancy was greater than 50% for the 11 most common sites and provides a current survey of cancer types by site present in the population reporting to our hospital
Ancient DNA and deep population structure in sub-Saharan African foragers
Multiple lines of genetic and archaeological evidence suggest that there were major demographic changes in the terminal Late Pleistocene epoch and early Holocene epoch of sub-Saharan Africa(1-4). Inferences about this period are challenging to make because demographic shifts in the past 5,000 years have obscured the structures of more ancient populations(3,5). Here we present genome-wide ancient DNA data for six individuals from eastern and south-central Africa spanning the past approximately 18,000 years (doubling the time depth of sub-Saharan African ancient DNA), increase the data quality for 15 previously published ancient individuals and analyse these alongside data from 13 other published ancient individuals. The ancestry of the individuals in our study area can be modelled as a geographically structured mixture of three highly divergent source populations, probably reflecting Pleistocene interactions around 80-20 thousand years ago, including deeply diverged eastern and southern African lineages, plus a previously unappreciated ubiquitous distribution of ancestry that occurs in highest proportion today in central African rainforest hunter-gatherers. Once established, this structure remained highly stable, with limited long-range gene flow. These results provide a new line of genetic evidence in support of hypotheses that have emerged from archaeological analyses but remain contested, suggesting increasing regionalization at the end of the Pleistocene epoch.
DNA analysis of 6 individuals from eastern and south-central Africa spanning the past approximately 18,000 years, and of 28 previously published ancient individuals, provides genetic evidence supporting hypotheses of increasing regionalization at the end of the Pleistocene.info:eu-repo/semantics/publishedVersio
Trends in tuberculosis and the influence of HIV infection in northern Malawi, 1988-2001.
OBJECTIVE: To document the changing incidence and patterns of tuberculosis (TB) in rural Africa and the extent to which they are influenced by HIV. METHODS: As part of longstanding epidemiological studies in Karonga District, Malawi, a series of case control studies of TB and HIV were conducted from 1988 onwards. Data from these studies, from a total population survey, and from the Malawi national census have been used to reconstruct the changes in the TB epidemic in the area from 1988 to 2001, examining the role of HIV. RESULTS: The incidence of all confirmed TB, and of new smear-positive TB, in adults increased to peak in the late 1990s but appears to have decreased since. Two-thirds of cases are now HIV positive. The rise in incidence was greatest in the 30-44-year-old age group and was particularly marked for women, leading to a decrease in the male : female ratio for TB incidence from 1.3 to 0.8. The proportion of new smear-positive TB cases attributable to HIV increased from 17% in 1988-1990 to 57% in 2000-2001, but the estimated rate of smear-positive TB in the absence of HIV decreased from 0.78/1000 to 0.45/1000. CONCLUSIONS: Without HIV the incidence of smear-positive TB would have fallen in this population. Instead it has risen and is predominantly affecting young adults and women. There is some evidence that the HIV-associated TB epidemic may have passed its peak
Invasive Non-typhoid Salmonellae Establish Systemic Intracellular Infection in HIV-Infected Adults: An Emerging Disease Pathogenesis
Background. Salmonellae are facultative intracellular pathogens. Non-typhoid salmonellae (NTS) cause selflimiting
mucosal disease in immunocompetent adults but invasive, recurrent disease among human immunodeficiency
virus (HIV)âinfected adults in Africa. The importance of intracellular NTS infection in HIV is unknown.
Methods. We performed quantitative pour-plate culture of blood samples obtained during febrile events among
495 Malawian adults on 871 occasions, and NTS were isolated at 158 events. Ninety-eight percent were HIV
infected, with a median CD4 count of 67 cells/mL. Lysis of pour plates and gentamicin exclusion testing were used
to investigate the presence of intracellular NTS in blood and bone marrow.
Results. Total viable NTS counts in blood were low (1 colony-forming unit [CFU]/mL) but correlated independently
with lower CD4 count and with IL-10 and IL-6 levels, especially at recurrence, suggesting failure to
clear intracellular infection. Viable NTS load in blood and bone marrow were closely correlated at index events,
but NTS were significantly concentrated in bone marrow, compared with blood samples, at recurrences (6 vs 1
CFU/mL), suggesting systemic tissue replication. Both lysis-pour-plating and gentamicin exclusion testing demonstrated
intracellular infection with 11 CFU/cell in both blood and bone marrow specimens. Intracellular bacteria
were demonstrated in bone marrow at both index and recurrent events, showing that this is an early and enduring
feature of pathogenesis, but intracellular NTS were detected in blood only at index events, particularly in patients
with a CD4 count !50 cells/mL. Intravascular NTS at recurrence may therefore reflect extracellular âoverspillâ from
an intracellular sanctuary site, following failure of immunological control.
Conclusions. Invasive NTS have established a new and emerging pathogenesis in the context of HIV infection in Africa
Recommended from our members
Rootâsoilâmicrobe interactions mediating nutrient fluxes in the rhizosphere
Plant roots have both direct and indirect effects on nutrient availabilities and fluxes in rhizosphere soil. Direct effects include impacts that are a consequence of root growth, water/nutrient uptake and secretion of compounds that promote solubility of poorly available elements such as phosphorus and iron. Indirect effects are largely a consequence of plantâmicrobe interactions, mediated by the release of organic compounds from roots that both shape rhizosphere microbial community structure and promote microbial nutrient cycling activity. In recent years, significant advances have been made in the quantification of root-mediated impacts on soil biogeochemical processes, demonstrating the importance of these interactions for nutrient cycling to support plant productivity and as a critical control point for the response of soils to environmental change. This is now supplemented with an appreciation that there is a strong element of regulation, both plant and microbial, in how the underlying interactions are established and maintained. This raises the exciting possibility that management of rootâmicrobiota interactions could be a realistic means of improving plant health and productivity, while potentially also mitigating environmental impacts. This chapter discusses progress in quantifying root impacts on soil processes and parallel advances in characterising the specificity of the plant-driven selection of associated microbiota. A clear opportunity for future research is to combine these approaches, functional -omics technologies and bioinformatics to guide next-generation crop breeding that targets both the plant and its associated microbiota (i.e. the holobiont), for productivity and resilience in sustainable agricultural systems