Expansion of the Cassava Brown Streak Disease Epidemic in Eastern Democratic Republic of Congo.

Cassava plays a key role in ensuring food security and generating income for smallholder farmers throughout Central Africa, particularly in the Democratic Republic of Congo (DRC). This status is threatened, however, by cassava brown streak disease (CBSD), which has expanded its incidence and range in eastern DRC. The study described here comprises the first extensive assessment of temporal change in the occurrence of CBSD and its causal viruses in DRC, based on surveys conducted during 2016 and 2018. Cassava fields were inspected in Ituri, Nord-Kivu, Sud-Kivu, Tanganyika, and Haut-Katanga provinces within eastern DRC to record foliar incidence and severity of CBSD. Leaf samples were collected for virus detection and species-level identification. New occurrences of CBSD, confirmed by virus diagnostic tests, were recorded in two provinces (Haut-Katanga and Sud-Kivu) and nine previously unaffected territories, covering an area of >62,000 km2, and at up to 900 km from locations of previously published reports of CBSD in DRC. Overall, average CBSD incidence within fields was 13.2% in 2016 and 16.1% in 2018. In the new spread zone of Haut-Katanga, incidence increased from 1.7 to 15.9%. CBSD is now present in provinces covering 321,000 km2, which is approximately 14% of the total area of DRC. This represents a major expansion of the CBSD epidemic, which was only recorded from one province (Nord-Kivu) in 2012. Both Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus were detected in Ituri, Nord-Kivu, and Sud-Kivu, but only CBSV was detected in Haut-Katanga. Overall, these results confirm the increasing threat that CBSD poses to cassava production in DRC and describe an important expansion in the African pandemic of CBSD.

Spatial Analysis of Temporal Changes in the Pandemic of Severe Cassava Mosaic Disease in Northwestern Tanzania.

To improve understanding of the dynamics of the cassava mosaic disease (CMD) pandemic front, geospatial approaches were applied to the analysis of 3 years' data obtained from a 2-by-2° (approximately 222-by-222 km) area of northwestern Tanzania. In total, 80 farmers' fields were assessed in each of 2009, 2010, and 2011, with 20 evenly distributed fields per 1-by-1° quadrant. CMD-associated variables (CMD incidence, CMD severity, vector-borne CMD infection, and vector abundance) increased in magnitude from 2009 to 2010 but showed little change from 2010 to 2011. Increases occurred primarily in the two westernmost quadrants of the study area. A pandemic "front" was defined by determining the values of CMD incidence and whitefly abundance where predicted disease gradients were greatest. The pandemic-associated virus (East African cassava mosaic virus-Uganda) and vector genotype (Bemisia tabaci sub-Saharan Africa 1-subgroup 1) were both present within the area bounded by the CMD incidence front but both also occurred ahead of the front. The average speed and direction of movement of the CMD incidence front (22.9 km/year; southeast) and whitefly abundance front (46.6 km/year; southeast) were calculated, and production losses due to CMD were estimated to range from US$4.3 million to 12.2 million.

Prevalence of pulmonary tuberculosis in adult population of Tanzania: a national survey, 2012.

SETTING: Tanzania is classified as one of the 22 high tuberculosis (TB) burden countries; however, the true burden of TB disease in the country remains unknown. OBJECTIVE: To assess the prevalence of bacteriologically confirmed pulmonary TB (PTB) in the adult population. DESIGN: This was a community-based cluster randomised survey with proportional-to-population-size selection of primary sampling units (districts). Participants were screened for TB using a symptom questionnaire and chest X-ray (CXR). Those with abnormal CXR and/or at least one symptom suggestive of TB were classified as individuals with presumptive TB, and asked to submit three sputum specimens for smear microscopy and culture. RESULTS: The weighted prevalence for sputum smear-positive TB cases was 249 per 100 000 adult population (95%CI 192-305) and that for bacteriologically confirmed TB cases was 293/100 000 (95%CI 228-358). Individuals aged ⩾45 years comprised 55% (71/129) of the identified smear-positive cases, but just 28% (6793/24 648) of the notified TB cases. CXR screening identified more TB cases than symptom screening. When weighted for human immunodeficiency virus prevalence among notified new smear-positive cases, the overall case detection of incident TB cases in 2012 was between 37% and 48%. CONCLUSIONS: The prevalence of sputum smear-positive PTB and bacteriologically confirmed PTB in the adult population was higher than previous World Health Organization estimates. There is a potential underestimation of the number of bacteriologically confirmed PTB cases in the adult population. The age distribution of prevalent cases suggests an epidemiological shift towards the older generations, which has been a sign of successful TB control activities in the past. However, the survey shows that many infectious TB cases are currently missed by the National Tuberculosis Programme.

National anti-tuberculosis drug resistance study in Tanzania.

OBJECTIVE: To assess the prevalence of anti-tuberculosis drug resistance in a national representative sample of tuberculosis (TB) patients in Tanzania according to recommended methodology. DESIGN: Cluster survey, with 40 clusters sampled proportional to size, of notified TB patients from all diagnostic centres in the country. RESULTS: The survey enrolled 1019 new and 148 retreatment patients. The adjusted prevalence of Mycobacterium tuberculosis strains resistant to any of the four first-line drugs in new patients was 8.3%, while the prevalence of multidrug-resistant TB (MDR-TB) was 1.1%. In retreatment patients, the crude prevalence for any resistance and for MDR-TB was respectively 20.6% and 3.9%. The prevalence of drug resistance did not differ in relapse patients compared to failure patients. These estimates are among the lowest in those African countries with an estimated level of drug resistance in the last 5 years. CONCLUSION: The low levels of drug resistance in Tanzania are likely due to a well performing TB control programme and the absence of noticeable involvement of the private sector in TB treatment.

Information and socioeconomic factors associated with early breastfeeding practices in rural and urban Morogoro, Tanzania.

UNLABELLED: A cross-sectional study was undertaken in a rural and an urban area in Tanzania with the aim of identifying factors related to early infant feeding practices. The study included 320 mothers from each area with infants below 7 mo of age. A significant proportion of both rural and urban mothers had erroneous beliefs about infant feeding practices. None of the socioeconomic, demographic or biological variables studied were associated with feeding practices. Urban residence was positively associated with the duration of exclusive but not predominant breastfeeding. Better knowledge about specific breastfeeding issues was positively associated with the duration of both exclusive and predominant breastfeeding. Ownership of a radio was positively associated with both exclusive and predominant breastfeeding in the rural area. Although both rural and urban mothers had a high antenatal clinic attendance rate, 65% of the rural and 14% of the urban mothers delivered at home. Urban mothers informed about breastfeeding at the antenatal clinic had better feeding practices. CONCLUSION: We hypothesize that exclusive breastfeeding is not a traditionally recognized practice and thus its duration is mainly associated with information and knowledge about breastfeeding. This suggests that information programmes to provide knowledge, beginning at antenatal visits, may reduce premature complementation, though additional support may also be required.

Exclusive breast-feeding is rarely practised in rural and urban Morogoro, Tanzania.

OBJECTIVE: To investigate and compare feeding practices among infants of less than 7 months of age in a rural and an urban area in Tanzania. DESIGN: Cross-sectional, questionnaire-based interview of mothers and focus group discussions with extension workers and community leaders. SETTING: Eleven villages in a rural district and 10 wards in an urban district in the Morogoro region, Tanzania, west of Dar es Salaam. SUBJECTS: Probability samples of mothers with infants of less than 7 months of age from each area). RESULTS: Exclusive breast-feeding was rarely practised in either the rural or urban areas investigated. However, the urban mothers initiated breast-feeding earlier, discarded colostrum less frequently, breast-fed exclusively for a longer period, gave breast milk as the first feed more often and delayed the introduction of solid foods for longer than their rural counterparts. The rural mothers, on the other hand, breast-fed their previous infants slightly longer than the urban mothers. CONCLUSIONS: The better performance of urban mothers could be partly due to sustained breast-feeding support in hospital settings and other campaigns which may not have reached the rural areas. In both the rural and urban areas more efforts are needed to encourage exclusive breast-feeding, to avoid premature complementation and, in the case of the urban areas, to protect extended breast-feeding.

Food consumption in rural and urban Tanzania.

Food consumption of 177 rural and 94 urban subjects (98 aged 12 years, 105 aged 35-44 years, and 68 aged 65-74 years) was studied in rural and urban Ilala district, Dar-es-Salaam, Tanzania, to characterize rural-urban differences in the meal and snack patterns and intakes of energy and nutrients. Food consumption of each subject was studied using 24 h dietary recall once during the rainy season and once during the dry season. Micro Nutrica PC database, expanded with East African food composition tables, was used in the nutrient intake analyses. All urban and 92% of rural subjects had three daily meals, and snacks were as commonly eaten in both areas of the survey. Foods of animal origin, e.g. meat and milk, were seldom used by the rural subjects. The WHO/FAO recommended minimal daily allowances of energy and protein were not reached by 26 and 15% of the rural subjects, respectively (10 and 4% of the urban subjects). Mean intake of folic acid by rural subjects was clearly below that of the urban subjects. Intakes of sucrose, mono- and disaccharides combined, polysaccharides, fibre and cholesterol differed markedly in all age groups in rural and urban circumstances (P < 0.05). Intake of fat and saturated fat was extremely low in all age groups, particularly in the rural subjects. The data suggest that (sub)clinical protein-energy malnutrition is prevelant in Tanzania, and that the high intakes of sucrose and cholesterol and the low intake of fibre by the urban subjects may increase the prevalence of dental caries and cardiovascular diseases in that population.