Cassava chips quality as influenced by cultivar, blanching time and slice thickness

Cassava forms part of diets in Kenya with both the roots and leaves being consumed as food. The short shelf-life of 72 hours and cyanogenic glucosides limit the extent of utilization. Currently, fried cassava chips and crisps are increasingly being consumed as snacks; and fried cassava chips are produced by street processors. The quality and safety of these products is not known, therefore, the current study was to establish the influence of cassava cultivar, blanching time and slice thickness on quality of fried cassava chips. Moisture, vitamin C and cyanide content in the raw cassava cultivars were determined before processing. The three raw cassava cultivars coded as MH95/0183, MM96/2480 and Fumba chai were washed, peeled and sliced into thickness of 6 mm, 10 mm and 20 mm. Equal groups of the slices were blanched at 950C for 0 minutes, 5 minutes and 10 minutes each and then subjected to frying temperature of 1700C. The physico-chemical and sensory properties of fried cassava chips were determined. Dry matter content, vitamin C content and cyanide levels significantly (p < 0.05) differed among the three raw cultivars except in MH95/0183 and MM96/2480. A strong positive relationship (r = 0.98) existed between moisture and cyanide contents in the raw cultivars. Mean cyanide levels in the three roots was: 37.04 mg/kg, 16.37 mg/kg and 48.48 mg/kg in MH95/0183, MM96/2480 and Fumba chai, respectively. Dry matter content was 36.79 %, 37.69 % and 30.42 % in MH95/0183, MM96/2480 and Fumba chai. The physico-chemical and sensory properties significantly (p < 0.05) differed within and across the cultivars as affected by processing conditions. Mean cyanide range was 1.4 - 11 mg/kg, oil content ranged 3.78 - 18.48 % and vitamin C content ranged 7.59 - 50.48 mg/100 g. Significant (p < 0.05) relationship (r = 0.707) existed between slice thickness and the redness color parameter. Cultivar, slice thickness and blanching time form important yardsticks in processing fried cassava chips. Proper choice of these parameters is, therefore, important in processing quality and safe cassava fries. Slice thickness of 6 mm combined with long blanching time of 10 minutes result in fried cassava chips with low and acceptable cyanide content as well as satisfactory consumer preference based on color, texture, oiliness and overall acceptability.Key words: cyanide, quality, cassava, slice thickness, cultivar, blanching, consumer preferenc

Effect of strikes by health workers on mortality between 2010 and 2016 in Kilifi, Kenya: a population-based cohort analysis

BACKGROUND: Health workers' strikes are a global occurrence. Kenya has had several strikes by health workers in recent years but their effect on mortality is unknown. We assessed the effect on mortality of six strikes by health workers that occurred from 2010 to 2016 in Kilifi, Kenya. METHODS: Using daily mortality data obtained from the Kilifi Health and Demographic Surveillance System, we fitted a negative binomial regression model to estimate the change in mortality during strike periods and in the 2 weeks immediately after strikes. We did subgroup analyses by age, cause of death, and strike week. FINDINGS: Between Jan 1, 2010, and Nov 30, 2016, we recorded 1 829 929 person-years of observation, 6396 deaths, and 128 strike days (median duration of strikes, 18·5 days [range 9-42]). In the primary analysis, no change in all-cause mortality was noted during strike periods (adjusted rate ratio [RR] 0·93, 95% CI 0·81-1·08; p=0·34). Weak evidence was recorded of variation in mortality rates by age group, with an apparent decrease among infants aged 1-11 months (adjusted RR 0·58, 95% CI 0·33-1·03; p=0·064) and an increase among children aged 12-59 months (1·75, 1·11-2·76; p=0·016). No change was noted in mortality rates in post-strike periods and for any category of cause of death. INTERPRETATION: The brief strikes by health workers during the period 2010-16 were not associated with obvious changes in overall mortality in Kilifi. The combined effects of private (and some public) health care during strike periods, a high proportion of out-of-hospital deaths, and a low number of events might have led us to underestimate the effect. FUNDING: Wellcome Trust and MRC Tropical Epidemiology Group

Invasive Salmonellosis in Kilifi, Kenya.

BACKGROUND: Invasive salmonelloses are a major cause of morbidity and mortality in Africa, but the incidence and case fatality of each disease vary markedly by region. We aimed to describe the incidence, clinical characteristics, and antimicrobial susceptibility patterns of invasive salmonelloses among children and adults in Kilifi, Kenya. METHODS: We analyzed integrated clinical and laboratory records for patients presenting to the Kilifi County Hospital between 1998 and 2014. We calculated incidence, and summarized clinical features and multidrug resistance. RESULTS: Nontyphoidal Salmonella (NTS) accounted for 10.8% and 5.8% of bacteremia cases in children and adults, respectively, while Salmonella Typhi accounted for 0.5% and 2.1%, respectively. Among 351 NTS isolates serotyped, 160 (45.6%) were Salmonella Enteritidis and 152 (43.3%) were Salmonella Typhimurium. The incidence of NTS in children aged <5 years was 36.6 per 100 000 person-years, being highest in infants aged <7 days (174/100 000 person-years). The overall incidence of NTS in children varied markedly by location and declined significantly during the study period; the pattern of dominance of the NTS serotypes also shifted from Salmonella Enteritidis to Salmonella Typhimurium. Risk factors for invasive NTS disease were human immunodeficiency virus infection, malaria, and malnutrition; the case fatality ratio was 22.1% (71/321) in children aged <5 years and 36.7% (11/30) in adults. Multidrug resistance was present in 23.9% (84/351) of NTS isolates and 46.2% (12/26) of Salmonella Typhi isolates. CONCLUSIONS: In Kilifi, the incidence of invasive NTS was high, especially among newborn infants, but typhoid fever was uncommon. NTS remains an important cause of bacteremia in children <5 years of age

Engaging Men in Prevention and Care for HIV/AIDS in Africa

Ed Mills and colleagues argue that a more balanced approach to gender is needed so that both men and women are involved in HIV treatment and prevention

Controlled Human Malaria Infection in Semi-Immune Kenyan Adults (CHMI-SIKA): a study protocol to investigate in vivo Plasmodium falciparum malaria parasite growth in the context of pre-existing immunity [version 2; peer review: 2 approved]

Malaria remains a major public health burden despite approval for implementation of a partially effective pre-erythrocytic malaria vaccine. There is an urgent need to accelerate development of a more effective multi-stage vaccine. Adults in malaria endemic areas may have substantial immunity provided by responses to the blood stages of malaria parasites, but field trials conducted on several blood-stage vaccines have not shown high levels of efficacy. We will use the controlled human malaria infection (CHMI) models with malaria-exposed volunteers to identify correlations between immune responses and parasite growth rates in vivo. Immune responses more strongly associated with control of parasite growth should be prioritized to accelerate malaria vaccine development. We aim to recruit up to 200 healthy adult volunteers from areas of differing malaria transmission in Kenya, and after confirming their health status through clinical examination and routine haematology and biochemistry, we will comprehensively characterize immunity to malaria using >100 blood-stage antigens. We will administer 3,200 aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (PfSPZ Challenge) by direct venous inoculation. Serial quantitative polymerase chain reaction to measure parasite growth rate in vivo will be undertaken. Clinical and laboratory monitoring will be undertaken to ensure volunteer safety. In addition, we will also explore the perceptions and experiences of volunteers and other stakeholders in participating in a malaria volunteer infection study. Serum, plasma, peripheral blood mononuclear cells and whole blood will be stored to allow a comprehensive assessment of adaptive and innate host immunity. We will use CHMI in semi-immune adult volunteers to relate parasite growth outcomes with antibody responses and other markers of host immunity. / Registration: ClinicalTrials.gov identifier NCT02739763

Estimating Loss to Follow-Up in HIV-Infected Patients on Antiretroviral Therapy: The Effect of the Competing Risk of Death in Zambia and Switzerland

BACKGROUND: Loss to follow-up (LTFU) is common in antiretroviral therapy (ART) programmes. Mortality is a competing risk (CR) for LTFU; however, it is often overlooked in cohort analyses. We examined how the CR of death affected LTFU estimates in Zambia and Switzerland. METHODS AND FINDINGS: HIV-infected patients aged ≥18 years who started ART 2004-2008 in observational cohorts in Zambia and Switzerland were included. We compared standard Kaplan-Meier curves with CR cumulative incidence. We calculated hazard ratios for LTFU across CD4 cell count strata using cause-specific Cox models, or Fine and Gray subdistribution models, adjusting for age, gender, body mass index and clinical stage. 89,339 patients from Zambia and 1,860 patients from Switzerland were included. 12,237 patients (13.7%) in Zambia and 129 patients (6.9%) in Switzerland were LTFU and 8,498 (9.5%) and 29 patients (1.6%), respectively, died. In Zambia, the probability of LTFU was overestimated in Kaplan-Meier curves: estimates at 3.5 years were 29.3% for patients starting ART with CD4 cells <100 cells/µl and 15.4% among patients starting with ≥350 cells/µL. The estimates from CR cumulative incidence were 22.9% and 13.6%, respectively. Little difference was found between naïve and CR analyses in Switzerland since only few patients died. The results from Cox and Fine and Gray models were similar: in Zambia the risk of loss to follow-up and death increased with decreasing CD4 counts at the start of ART, whereas in Switzerland there was a trend in the opposite direction, with patients with higher CD4 cell counts more likely to be lost to follow-up. CONCLUSIONS: In ART programmes in low-income settings the competing risk of death can substantially bias standard analyses of LTFU. The CD4 cell count and other prognostic factors may be differentially associated with LTFU in low-income and high-income settings

Impact of health workers’ strikes on mortality between 2010-2016 in Kilifi, Kenya: a population-based cohort analysis

Background Health workers’ strikes are a global phenomenon with reports of 620 such strikes in sub-Saharan Africa over a 20-year period. Kenya has had several strikes in recent years, but their impact on mortality is unknown. We assessed the effect on mortality of six strikes that occurred from 2010-2016 in Kilifi, Kenya using data from the Kilifi Health and Demographic Surveillance System. Methods Using daily mortality data from January 2010 to November 2016, we fitted a negative binomial regression model to estimate the change in mortality during strike periods, and in the two weeks immediately after strikes. We conducted subgroup analyses by age, cause of death and strike week. Findings There were 1,892,099 person-years of observation, 6,396 deaths and 128 strike days (median duration 19 days). In the primary analysis, there was no change in all-cause mortality during the strike periods [adjusted Rate ratio (aRR) 0.93, 95% CI 0.81, 1.08; p=0.338]. There was weak evidence of variation in mortality rates by age-group with an apparent decrease among 1-11-month-olds (aRR 0.58 CI 0.33, 1.03 p=0.064) and an increase among 12-59-month-olds (aRR 1.75, 95% CI 1.11, 2.76; p=0.016). There was no change in mortality rates in the post-strike period and for any cause of death category. Interpretation The brief health workers’ strikes during the 2010-2016 period were not associated with obvious changes in overall mortality in Kilifi. The combined effects of private and some public health care (at a paediatric High Dependency Unit) during strike periods, a high proportion of out-of-hospital deaths, and limited number of events may have led us to underestimate the effect