Evaluation of the effectiveness of a latrine intervention in the reduction of childhood diarrhoeal health in Nyando District, Kisumu County, Kenya.

Community-led total sanitation (CLTS) is an intervention that strives to end the practice of open defaecation. This study measured the effectiveness of CLTS in Nyando District by examining the association between community open defaecation-free (ODF) status and childhood diarrhoeal illness. A cross-sectional study design was used among households with children ⩽5 years old to ascertain information on acute diarrhoea in the past year (outcome), sanitation and health behaviours. Water testing was conducted to determine Escherichia coli and turbidity levels for 55 water sources. Data were obtained from 210 parents or caregivers from an ODF community and 216 parents or caregivers in a non-ODF community. The non-ODF participants reported a non-significant 16% increased risk of diarrhoea compared with the participants from the ODF community. Children's HIV positivity (adjusted prevalence ratio (aPR) = 2.29; 95% CI 2.07-2.53), unsafe child stool disposal (aPR = 1.92; 95% CI 1.74-2.12) and low household income (aPR = 1.93; 95% CI 1.46-2.56) were associated with diarrhoea, in the non-ODF community. The ODF location had a higher percentage of E. coli in the drinking water compared with the non-ODF location (76.7% vs. 60%). Diarrhoeal disease rates in children ⩽5 years old did not differ by whether a latrine intervention was implemented. Water sampling findings suggest water safety may have decreased the effectiveness of the CLTS' improvement of childhood diarrhoea. Improved water treatment practices, safe stool disposal and education may improve the CLTS intervention in ODF communities and therefore reduced the risk of childhood diarrhoea.

South African National Cancer Registry: Effect of withheld data from private health systems on cancer incidence estimates.

BACKGROUND: The National Cancer Registry (NCR) was established as a pathology-based cancer reporting system. From 2005 to 2007, private health laboratories withheld cancer reports owing to concerns regarding voluntary sharing of patient data. OBJECTIVES: To estimate the impact of under-reported cancer data from private health laboratories. METHODS: A linear regression analysis was conducted to project expected cancer cases for 2005-2007. Differences between actual and projected figures were calculated to estimate percentage under-reporting. RESULTS: The projected NCR case total varied from 53,407 (3.8% net increase from actual cases reported) in 2005 to 54,823 (3.7% net increase) in 2007. The projected number of reported cases from private laboratories in 2005 was 26,359 (19.7% net increase from actual cases reported), 27,012 (18.8% net increase) in 2006 and 27,666 (28.4% net increase) in 2007. CONCLUSION: While private healthcare reporting decreased by 28% from 2005 to 2007, this represented a minimal impact on overall cancer reporting (net decrease of <4%).

Origins and environmental mobility of antibiotic resistance genes, virulence factors and bacteria in a tidal creek's watershed.

AIMS: To compare bacterial compositions of watershed run-offs released by a human settlement and a forested area, and to evaluate their role as carriers of antibiotic resistance and virulence genes. METHODS AND RESULTS: Run-offs from a forested area and a small settlement in a tidal creek' s watershed were compared for bacterial composition and profiles of 16 tetracycline resistance (TRG), eight virulence (VG) and integrase1 and 2 genes. Integrase 1 gene was detected only once. No integrase 2 gene was observed. VGs were detected only in settlement's run-offs, and TRG incidence frequency there was twice as high as in the forest's run-offs. Gene incidences revealed a positive correspondence to the rainfall, and weak correlations to water parameters. Metagenomic, Principle Coordinates and Shannon analyses together revealed distinctive bacterial compositions of the forest's and settlement's run-offs. Passage of the latter through a salt marsh resulted in the elimination of TRGs and three-fold decrease in VG incidence, and their bacterial composition was shifted towards that of the tidal creek. CONCLUSIONS: The settlement was a major source of TRGs and VGs in the watershed, but these contaminants were mitigated by a salt marsh system. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data revealed the role of small settlements in biological contamination of the coastal waters. They also indicated that salt marshes are capable of reducing not only chemical but also biological contamination of run-offs.

Vitamin D receptor gene polymorphisms and sputum conversion time in pulmonary tuberculosis patients.

A cohort of pulmonary tuberculosis (TB) patients in a South African admixed population was investigated to determine if the vitamin D receptor gene (VDR) polymorphisms FokI, ApaI, and TaqI are associated with TB susceptibility or time to sputum conversion, and to investigate other clinical and demographic factors affecting the rate of response to treatment. Firstly, a case-control association study of 249 TB cases and 352 healthy controls was carried out to investigate association of VDR polymorphisms with TB susceptibility. Secondly, a cohort of pulmonary tuberculosis patients with conversion times for both sputum smear (n=220) and culture (n=222) were analysed to determine factors contributing to mycobacterial resolution in sputum. Age and gender adjusted Cox regression models were constructed. Our results indicate that the extent of disease at diagnosis was predictive of both smear and culture conversion times in the final models. Smoking status and VDR genotype contributed independently to smear conversion time, with ApaI 'AA' genotype and TaqI 'T'-containing genotypes predictive of a faster response to TB chemotherapy. We did not find an association between VDR genotype and TB in the case-control study. We conclude that the time taken for an individual to convert to sputum negativity while on antituberculosis therapy can be independently predicted by the VDR genotype.

SP110 polymorphisms are not associated with pulmonary tuberculosis in a South African population.

Susceptibility to tuberculosis (TB) in mice has recently been attributed to the Ipr1 gene. Polymorphisms in the human homologue, SP110, have been investigated in various populations with only one study finding an association with TB susceptibility. We investigated eight SP110 polymorphisms in a South African population, including two novel polymorphisms. No significant association was found with any of the polymorphisms investigated, including two polymorphisms that were previously found to be associated with TB susceptibility in West African populations.

HLA class II disease associations in southern Africa.

Southern Africa harbors several population groups representing a diversity of gene pool origins. This provides a unique opportunity to study genetic disease predisposition in these populations against a common environmental background. Human leukocyte antigen (HLA) association studies of these populations could improve knowledge on inter-population variation and HLA-related disease susceptibility. The aim of this paper is to review HLA class II disease associations reported for southern African population groups, compare them with findings in other populations and identify those unique to southern Africa. A number of HLA class II disease associations appear to be unique to southern African populations. These include DRB1*14011 association with insulin-dependent diabetes mellitus susceptibility in the Xhosa and DRB1*10 and DQB1*0302 with rheumatoid arthritis susceptibility in the South African (SA) Indian and SA Coloreds, respectively. A noteworthy similarity in class II disease association was observed among southern African Caucasoid and their European parental populations. Unique HLA class II disease associations observed in southern Africa are consistent with the notion that unique environmental and natural selective factors have resulted in certain ethnic-specific HLA class II disease associations, while common HLA class II disease associations found across different populations support the notion that common diseases are caused by common, ancient alleles present in indigenous African populations.

Biomagnetic neurosensors.

Non-invasive measurement of the neuromodulatory activity of certain analytes is now possible through the use of biomagnetic stimulation and detection techniques. The timely development of room-temperature instrumentation and of more effective techniques for coupling neurons to transducers are the critical elements for rapid progress in this field.

Biomagnetic neurosensors. 4. Design and optimization for analytical use.

Biomagnetic neurosensors based on magnetic stimulation and magnetic detection of neural events depend critically upon the effective matching of the magnetic transducers and the neural tissue employed. Although the properties of wire-wrapped ferrite core transducers can be predicted from electromagnetic fundamentals, meaningful analytical measurements using real nerves as molecular recognition elements require additional calibration and optimization steps in order to achieve good system response and lifetimes. This note provides some design guidelines and experimental test procedures to enable potential users to employ biomagnetic neurosensors in other laboratories.

Biomagnetic neurosensors. 3. Noninvasive sensors using magnetic stimulation and biomagnetic detection.

A noninvasive biomagnetic sensor system that uses magnetic toroids for both neural stimulation and detection is described. It is shown that analytical signals obtained by direct magnetic detection (no signal averaging) compare favorably with electrical monitoring and that dose-response curves for local anesthetics correlate well between the two methods. Neural lifetimes are significantly extended when the noninvasive biomagnetic sensing system is used.

Biomagnetic neurosensors. 2. Magnetically stimulated sensors.

We report the generation of action potentials in crayfish neurons by magnetic pulses for analytical purposes. A copper wire toroid, containing a ferrite core, was placed around the nerve bundle, and square wave current pulses were sent through the wire to generate a magnetic field. The magnetic field generated an action potential in the neuron that was detected downfield by a pickup microelectrode. The biosensor was used to detect local anesthetics by monitoring the time necessary for complete blockage of the action potential. Techniques for improving the efficiency and lifetimes of neural biosensors are discussed.

Development and persistence of antibody in a high risk institutionalized population given plasma-derived hepatitis B vaccine.

Three hundred and twenty-two (322) persons with severe mental handicaps were given plasma-derived hepatitis B vaccine (20 micrograms dose at 0, 1 and 6 months). Following the third injection, 95% of the vaccinees were positive for anti-HBs, while 92% achieved a protective level of antibody (greater than or equal to 10 mIU ml-1) with a geometric mean titre of 2568 mIU ml-1. Females responded better than males. Antibody responses declined with increasing age in both sexes, but they were not significantly influenced by body weight. Persistence of antibody in responders was followed over 4 years. The proportion of responders maintaining greater than or equal to 10 mIU ml-1 was a function of initial antibody titre but was not significantly affected by sex, age or body weight. Overall, 76% of the responders are estimated to have greater than or equal to 10 mIU ml-1 of anti-HBs 4 years after the first injection of vaccine.

Low prevalence of hepatitis B infections among residents of an institution for the mentally retarded in New Mexico.

Residential institutions for the mentally retarded are considered high-risk settings for hepatitis B (HB) infection. Accordingly, HB vaccine is recommended for susceptible clients and selected staff of such facilities. However, a serologic screening program among 364 residents of Los Lunas Hospital and Training School (LLHTS) in New Mexico found only 11 residents to be anti-HBc positive (3%) and only one of these residents was also HBsAg-positive (0.3%). The unexpectedly low prevalence of HB infections at LLHTS probably reflects infrequent HB introductions into the institution. Using these serologic data, a vaccination program was instituted to prevent HB infection among LLHTS residents, thereby eliminating the need for mass screening and HB vaccination of LLHTS employees. Serologic screening among residents of other smaller institutions for the mentally retarded is recommended before design of HB prevention programs for clients and staff.

Role of coagulopathy in newborn intracranial hemorrhage.

Fifty newborn infants of less than 33 weeks' gestation were followed prospectively from birth with serial coagulation and real-time ultrasound studies. A significant association of hypocoagulability in the first four hours of life with subsequent onset or progression of intraventricular or other clinical hemorrhages was documented. Abnormalities included lower values for fibrinogen, platelet count, antithrombin III, and factor VIII with higher values for fibrin monomer and longer Laidlaw whole blood clotting times. These abnormalities tended to correct spontaneously in surviving infants. An association between gestational complications and incidence of hypocoagulability and intracranial hemorrhage (ICH) was noted. Babies of preeclamptic mothers had fewer abnormalities and babies born to mothers with premature rupture of membranes and suspected amnionitis manifested more hypocoagulability and more severe intracranial hemorrhages.