Tesfaye Teferi

Individual, household and environmental risk factors for malaria infection in Amhara, Oromia and SNNP regions of Ethiopia

We assessed malaria infection in relation to age, altitude, rainfall, socio-economic factors and coverage of control measures in a representative sample of 11437 people in Amhara, Oromia and SNNP regions of Ethiopia in December 2006-January 2007. Surveys were conducted in 224 randomly selected clusters of 25 households (overall sample of 27884 people in 5708 households). In 11538 blood slides examined from alternate households (83% of those eligible), malaria prevalence in people of all ages was 4.1% (95% CI 3.4-4.9), with 56.5% of infections being Plasmodium falciparum. At least one mosquito net or one long-lasting insecticidal net (LLIN) was present in 37.0% (95% CI 31.1-43.3) and 19.6% (95% CI 15.5-24.5) of households, respectively. In multivariate analysis (n=11437; 82% of those eligible), significant protective factors were: number of LLINs per household (odds ratio [OR] (per additional net)=0.60; 95% CI 0.40-0.89), living at higher altitude (OR (per 100 m)=0.95; 95% CI 0.90-1.00) and household wealth (OR (per unit increase in asset index)=0.79; 95% CI 0.66-0.94). Malaria prevalence was positively associated with peak monthly rainfall in the year before the survey (OR (per additional 10 mm rain)=1.10; 95% CI 1.03-1.18). People living above 2000 m and people of all ages are still at significant risk of malaria infection.

A novel electronic data collection system for large-scale surveys of neglected tropical diseases.

Background Large cross-sectional household surveys are common for measuring indicators of neglected tropical disease control programs. As an alternative to standard paper-based data collection, we utilized novel paperless technology to collect data electronically from over 12,000 households in Ethiopia. Methodology We conducted a needs assessment to design an Android-based electronic data collection and management system. We then evaluated the system by reporting results of a pilot trial and from comparisons of two, large-scale surveys; one with traditional paper questionnaires and the other with tablet computers, including accuracy, person-time days, and costs incurred. Principle Findings The electronic data collection system met core functions in household surveys and overcame constraints identified in the needs assessment. Pilot data recorders took 264 (standard deviation (SD) 152 sec) and 260 sec (SD 122 sec) per person registered to complete household surveys using paper and tablets, respectively (P = 0.77). Data recorders felt a lack of connection with the interviewee during the first days using electronic devices, but preferred to collect data electronically in future surveys. Electronic data collection saved time by giving results immediately, obviating the need for double data entry and cross-correcting. The proportion of identified data entry errors in disease classification did not differ between the two data collection methods. Geographic coordinates collected using the tablets were more accurate than coordinates transcribed on a paper form. Costs of the equipment required for electronic data collection was approximately the same cost incurred for data entry of questionnaires, whereas repeated use of the electronic equipment may increase cost savings. Conclusions/Significance Conducting a needs assessment and pilot testing allowed the design to specifically match the functionality required for surveys. Electronic data collection using an Android-based technology was suitable for a large-scale health survey, saved time, provided more accurate geo-coordinates, and was preferred by recorders over standard paper-based questionnaires.

Intestinal parasite prevalence in an area of ethiopia after implementing the SAFE strategy, enhanced outreach services, and health extension program.

Background The SAFE strategy aims to reduce transmission of Chlamydia trachomatis through antibiotics, improved hygiene, and sanitation. We integrated assessment of intestinal parasites into large-scale trachoma impact surveys to determine whether documented environmental improvements promoted by a trachoma program had collateral impact on intestinal parasites. Methodology We surveyed 99 communities for both trachoma and intestinal parasites (soil-transmitted helminths, Schistosoma mansoni, and intestinal protozoa) in South Gondar, Ethiopia. One child aged 2–15 years per household was randomly selected to provide a stool sample of which about 1 g was fixed in sodium acetate-acetic acid-formalin, concentrated with ether, and examined under a microscope by experienced laboratory technicians. Principal Findings A total of 2,338 stool specimens were provided, processed, and linked to survey data from 2,657 randomly selected children (88% response). The zonal-level prevalence of Ascaris lumbricoides, hookworm, and Trichuris trichiura was 9.9% (95% confidence interval (CI) 7.2–12.7%), 9.7% (5.9–13.4%), and 2.6% (1.6–3.7%), respectively. The prevalence of S. mansoni was 2.9% (95% CI 0.2–5.5%) but infection was highly focal (range by community from 0–52.4%). The prevalence of any of these helminth infections was 24.2% (95% CI 17.6–30.9%) compared to 48.5% as found in a previous study in 1995 using the Kato-Katz technique. The pathogenic intestinal protozoa Giardia intestinalis and Entamoeba histolytica/E. dispar were found in 23.0% (95% CI 20.3–25.6%) and 11.1% (95% CI 8.9–13.2%) of the surveyed children, respectively. We found statistically significant increases in household latrine ownership, use of an improved water source, access to water, and face washing behavior over the past 7 years. Conclusions Improvements in hygiene and sanitation promoted both by the SAFE strategy for trachoma and health extension program combined with preventive chemotherapy during enhanced outreach services are plausible explanations for the changing patterns of intestinal parasite prevalence. The extent of intestinal protozoa infections suggests poor water quality or unsanitary water collection and storage practices and warrants targeted intervention.

Evaluation of three years of the SAFE strategy (Surgery, Antibiotics, Facial cleanliness and Environmental improvement) for trachoma control in five districts of Ethiopia hyperendemic for trachoma:

Trachoma surveys were conducted at baseline in five districts of Amhara National Regional State, Ethiopia (7478 participants in 1096 households) and at 3-year evaluation (5762 participants in 1117 households). Uptake of SAFE was assessed with programme monitoring data and interviews, and children (1-6 years) were swabbed for detection of ocular Chlamydia. At evaluation, 23,933 people had received trichiasis surgery; 93% of participants reported taking azithromycin at least once; 67% of household respondents (range 46-93) reported participation in trachoma health education; and household latrine coverage increased from 2% to 34%. In children aged 1-9 years percentage decline, by district, for outcomes was: 32% (95% CI 19-48) to 88% (95% CI 83-91) for trachomatous inflammation-follicular (TF); 87% (95% CI 83-91) to 99% (95% CI 97-100) for trachomatous inflammation-intense (TI); and 31% increase (95% CI -42 to -19) to 89% decrease (95% CI 85-93) for unclean face; and in adults percentage decline in trichiasis was 45% (95% CI -13 to 78) to 92% (95% CI 78-96). Overall prevalence of swabs positive for ocular Chlamydia was 3.1%. Although there were substantial reductions in outcomes in children and adults, the presence of ocular Chlamydia and TF in children suggests ongoing transmission. Continued implementation of SAFE is warranted.

Risk factors for active trachoma in children and trichiasis in adults: a household survey in Amhara Regional State, Ethiopia

Identification of risk factors is essential for planning and implementing effective trachoma control programmes. We aimed to investigate risk factors for active trachoma and trichiasis in Amhara Regional State, Ethiopia. A survey was undertaken and eligible participants (children aged 1-9 years and adults aged 15 years and above) examined for trachoma. Risk factors were assessed through interviews and observations. Using ordinal logistic regression, associations between signs of active trachoma in children and potential risk factors were explored. Associations between trichiasis in adults and potential risk factors were investigated using conventional logistic regression. A total of 5427 children from 2845 households and 9098 adults from 4039 households were included in the analysis. Ocular discharge [odds ratio (OR)=5.9; 95% CI 4.8-7.2], nasal discharge (OR=1.6; 95% CI 1.3-1.9), thatch roof in household (OR=1.3; 95% CI 1.0-1.5), no electricity in household (OR=2.4; 95% CI 1.3-4.3) and increasing altitude (Ptrend<0.001) were independently associated with severity of active trachoma. Trichiasis was associated with increasing age (ORper 5 year increase=1.5; 95% CI 1.4-1.7), female gender (OR=4.5; 95% CI 3.5-5.8), increasing prevalence of active trachoma in children (Ptrend=0.003) and increasing altitude (Ptrend=0.015).

Performance of local light microscopy and the ParaScreen Pan/Pf rapid diagnostic test to detect malaria in health centers in Northwest Ethiopia.

Background Diagnostic tests are recommended for suspected malaria cases before treatment, but comparative performance of microscopy and rapid diagnostic tests (RDTs) at rural health centers has rarely been studied compared to independent expert microscopy. Methods Participants (N = 1997) with presumptive malaria were recruited from ten health centers with a range of transmission intensities in Amhara Regional State, Northwest Ethiopia during October to December 2007. Microscopy and ParaScreen Pan/Pf® RDT were done immediately by health center technicians. Blood slides were re-examined later at a central laboratory by independent expert microscopists. Results Of 1,997 febrile patients, 475 (23.8%) were positive by expert microscopists, with 57.7% P.falciparum, 24.6% P.vivax and 17.7% mixed infections. Sensitivity of health center microscopists for any malaria species was >90% in five health centers (four of which had the highest prevalence), >70% in nine centers and 44% in one site with lowest prevalence. Specificity for health center microscopy was very good (>95%) in all centers. For ParaScreen RDT, sensitivity was ≥90% in three centers, ≥70% in six and <60% in four centers. Specificity was ≥90% in all centers except one where it was 85%. Conclusions Health center microscopists performed well in nine of the ten health centers; while for ParaScreen RDT they performed well in only six centers. Overall the accuracy of local microscopy exceeded that of RDT for all outcomes. This study supports the introduction of RDTs only if accompanied by appropriate training, frequent supervision and quality control at all levels. Deficiencies in RDT use at some health centers must be rectified before universal replacement of good routine microscopy with RDTs. Maintenance and strengthening of good quality microscopy remains a priority at health center level.

Effect of a community intervention with pit latrines in five districts of Amhara, Ethiopia:

Objective  To evaluate the change in household latrine coverage and investigated predictors of latrine uptake after 3 years of implementation of trachoma control interventions in Dera, Ebinat, Estie, Enebsie Sarmedir and Huleteju Enese districts of Amhara, Ethiopia.

Estimation of effects of community intervention with Antibiotics, Facial cleanliness, and Environmental improvement (A,F,E) in five districts of Ethiopia hyperendemic for trachoma.

Aims The WHO recommends the SAFE (surgery, antibiotics, facial cleanliness and environmental improvement) strategy for trachoma control. We aimed to investigate the association between active trachoma and community intervention with antibiotics, facial cleanliness, environmental improvement (A,F,E) components of SAFE in five trachoma hyperendemic districts of Amhara region, Ethiopia. Methods Cluster random surveys were undertaken to evaluate SAFE following 3 years of interventions. Children aged 1–9 years were examined for trachoma signs using the WHO simplified grading system and structured questionnaires used to assess uptake of A, F and E. Active trachoma signs (trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI)) were used to derive an ordinal severity score where TI was considered more severe than TF. Associations between active trachoma and potential factors were investigated using ordinal logistic multilevel regression models. Results A total of 1813 children aged 1–9 years were included in the analysis. Factors independently associated with reduced odds of active trachoma signs were: number of times treated with azithromycin (p-trend=0.026); months since last mass azithromycin distribution (p-trend<0.001); clean face (OR=0.6; 95% CI 0.5 to 0.8); and household pit latrine (OR=0.8; 95% CI 0.7 to 0.9). Conclusion These findings are important, since they make the case for continued implementing the A,F,E interventions simultaneously, and suggest appropriate timing of SAFE evaluations within 6–12 months after the last mass azithromycin distribution.

Trachoma among children in community surveys from four African countries and implications of using school surveys for evaluating prevalence

BACKGROUND School surveys provide a convenient platform to obtain large child cohorts from multiple communities and are widely used as a proxy to determine community prevalence of neglected tropical diseases. The purpose of this study was to compare trachoma prevalence between preschool- and school-aged children and children who attend and do not attend school. METHODS We analysed data from community-based trachoma surveys conducted from 2008-2011 in Ethiopia, Mali, Niger and Nigeria. The surveys utilised a cross-sectional, randomised cluster design. Individual-level data on school attendance was collected. RESULTS Overall, 75 864 children aged 1-15 years from 2100 communities were included in the analysis. The prevalence of trachomatous inflammation follicular (TF) among these children in surveyed districts was 19.1% (95% CI 17.9-20.2%) in Ethiopia, 6.2% (95% CI 5.4-6.9%) in Niger, 4.6% (95% CI 4.2-4.9%) in Mali and 4.2% (95% CI 3.5-4.9%) in Nigeria. Controlling for age, sex and clustering, the OR of TF for school-attendees compared to non-attendees was 0.64 (95% CI 0.56-0.73) in Ethiopia, 0.67 (95% CI 0.56-0.80) in Mali, 1.03 (95% CI 0.81-1.16) in Niger and 1.06, (95% CI 0.65-1.73) in Nigeria. CONCLUSION Estimating the prevalence of trachoma through examination of only school-going children risks underestimating the true prevalence.

Prevalence of trachoma at sub-district level in Ethiopia: Determining when to stop mass azithromycin distribution:

Background To eliminate blinding trachoma, the World Health Organization emphasizes implementing the SAFE strategy, which includes annual mass drug administration (MDA) with azithromycin to the whole population of endemic districts. Prevalence surveys to assess impact at the district level are recommended after at least 3 years of intervention. The decision to stop MDA is based on a prevalence of trachomatous inflammation follicular (TF) among children aged 1–9 years below 5% at the sub-district level, as determined by an additional round of surveys limited within districts where TF prevalence is below 10%. We conducted impact surveys powered to estimate prevalence simultaneously at the sub-district and district in two zones of Amhara, Ethiopia to determine whether MDA could be stopped. Methodology Seventy-two separate population-based, sub-district surveys were conducted in 25 districts. In each survey all residents from 10 randomly selected clusters were screened for clinical signs of trachoma. Data were weighted according to selection probabilities and adjusted for correlation due to clustering. Principal Findings Overall, 89,735 residents were registered from 21,327 households of whom 72,452 people (80.7%) were examined. The prevalence of TF in children aged 1–9 years was below 5% in six sub-districts and two districts. Sub-district level prevalence of TF in children aged 1–9 years ranged from 0.9–76.9% and district-level from 0.9–67.0%. In only one district was the prevalence of trichiasis below 0.1%. Conclusions/Significance The experience from these zones in Ethiopia demonstrates that impact assessments designed to give a prevalence estimate of TF at sub-district level are possible, although the scale of the work was challenging. Given the assessed district-level prevalence of TF, sub-district-level surveys would have been warranted in only five districts. Interpretation was not as simple as stopping MDA in sub-districts below 5% given programmatic challenges of exempting sub-districts from a highly regarded program and the proximity of hyper-endemic sub-districts.