Externally validated prediction models for pre-eclampsia: systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the performance of existing externally validated prediction models for pre-eclampsia (PE) (specifically, any-onset, early-onset, late-onset and preterm PE).

METHODS

A systematic search was conducted in five databases (MEDLINE, EMBASE, Emcare, CINAHL and Maternity & Infant Care Database) and using Google Scholar/reference search to identify studies based on the Population, Index prediction model, Comparator, Outcome, Timing and Setting (PICOTS) approach until 20 May 2023. We extracted data using the CHARMS checklist and appraised the risk of bias using the PROBAST tool. A meta-analysis of discrimination and calibration performance was conducted when appropriate.

RESULTS

Twenty-three studies reported 52 externally validated prediction models for PE (one preterm, 20 any-onset, 17 early-onset and 14 late-onset PE models). No model had the same set of predictors. Fifteen any-onset PE models were validated externally once, two were validated twice and three were validated three times, while the Fetal Medicine Foundation (FMF) competing-risks model for preterm PE prediction was validated widely in 16 different settings. The most common predictors were maternal characteristics (prepregnancy body mass index, prior PE, family history of PE, chronic medical conditions and ethnicity) and biomarkers (uterine artery pulsatility index and pregnancy-associated plasma protein-A). The FMF model for preterm PE (triple test plus maternal factors) had the best performance, with a pooled area under the receiver-operating-characteristics curve (AUC) of 0.90 (95% prediction interval (PI), 0.76-0.96), and was well calibrated. The other models generally had poor-to-good discrimination performance (median AUC, 0.66 (range, 0.53-0.77)) and were overfitted on external validation. Apart from the FMF model, only two models that were validated multiple times for any-onset PE prediction, which were based on maternal characteristics only, produced reasonable pooled AUCs of 0.71 (95% PI, 0.66-0.76) and 0.73 (95% PI, 0.55-0.86).

CONCLUSIONS

Existing externally validated prediction models for any-, early- and late-onset PE have limited discrimination and calibration performance, and include inconsistent input variables. The triple-test FMF model had outstanding discrimination performance in predicting preterm PE in numerous settings, but the inclusion of specialized biomarkers may limit feasibility and implementation outside of high-resource settings. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

External validation of prognostic models to predict stillbirth using International Prediction of Pregnancy Complications (IPPIC) Network database: individual participant data meta-analysis

OBJECTIVE

Stillbirth is a potentially preventable complication of pregnancy. Identifying women at high risk of stillbirth can guide decisions on the need for closer surveillance and timing of delivery in order to prevent fetal death. Prognostic models have been developed to predict the risk of stillbirth, but none has yet been validated externally. In this study, we externally validated published prediction models for stillbirth using individual participant data (IPD) meta-analysis to assess their predictive performance.

METHODS

MEDLINE, EMBASE, DH-DATA and AMED databases were searched from inception to December 2020 to identify studies reporting stillbirth prediction models. Studies that developed or updated prediction models for stillbirth for use at any time during pregnancy were included. IPD from cohorts within the International Prediction of Pregnancy Complications (IPPIC) Network were used to validate externally the identified prediction models whose individual variables were available in the IPD. The risk of bias of the models and cohorts was assessed using the Prediction study Risk Of Bias ASsessment Tool (PROBAST). The discriminative performance of the models was evaluated using the C-statistic, and calibration was assessed using calibration plots, calibration slope and calibration-in-the-large. Performance measures were estimated separately in each cohort, as well as summarized across cohorts using random-effects meta-analysis. Clinical utility was assessed using net benefit.

RESULTS

Seventeen studies reporting the development of 40 prognostic models for stillbirth were identified. None of the models had been previously validated externally, and the full model equation was reported for only one-fifth (20%, 8/40) of the models. External validation was possible for three of these models, using IPD from 19 cohorts (491 201 pregnant women) within the IPPIC Network database. Based on evaluation of the model development studies, all three models had an overall high risk of bias, according to PROBAST. In the IPD meta-analysis, the models had summary C-statistics ranging from 0.53 to 0.65 and summary calibration slopes ranging from 0.40 to 0.88, with risk predictions that were generally too extreme compared with the observed risks. The models had little to no clinical utility, as assessed by net benefit. However, there remained uncertainty in the performance of some models due to small available sample sizes.

CONCLUSIONS

The three validated stillbirth prediction models showed generally poor and uncertain predictive performance in new data, with limited evidence to support their clinical application. The findings suggest methodological shortcomings in their development, including overfitting. Further research is needed to further validate these and other models, identify stronger prognostic factors and develop more robust prediction models. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of stillbirth: an umbrella review of evaluation of prognostic variables

BACKGROUND

Stillbirth accounts for over 2 million deaths a year worldwide and rates remains stubbornly high. Multivariable prediction models may be key to individualised monitoring, intervention or early birth in pregnancy to prevent stillbirth.

OBJECTIVES

To collate and evaluate systematic reviews of factors associated with stillbirth in order to identify variables relevant to prediction model development.

SEARCH STRATEGY

MEDLINE, Embase, DARE and Cochrane Library databases and reference lists were searched up to November 2019.

SELECTION CRITERIA

We included systematic reviews of association of individual variables with stillbirth without language restriction.

DATA COLLECTION AND ANALYSIS

Abstract screening and data extraction were conducted in duplicate. Methodological quality was assessed using AMSTAR and QUIPS criteria. The evidence supporting association with each variable was graded.

RESULTS

The search identified 1198 citations. Sixty-nine systematic reviews reporting 64 variables were included. The most frequently reported were maternal age (n = 5), body mass index (n = 6) and maternal diabetes (n = 5). Uterine artery Doppler appeared to have the best performance of any single test for stillbirth. The strongest evidence of association was for nulliparity and pre-existing hypertension.

CONCLUSION

We have identified variables relevant to the development of prediction models for stillbirth. Age, parity and prior adverse pregnancy outcomes had a more convincing association than the best performing tests, which were PAPP-A, PlGF and UtAD. The evidence was limited by high heterogeneity and lack of data on intervention bias.

TWEETABLE ABSTRACT

Review shows key predictors for use in developing models predicting stillbirth include age, prior pregnancy outcome and PAPP-A, PLGF and Uterine artery Doppler.

Can risk prediction models help us individualise stillbirth prevention? A systematic review and critical appraisal of published risk models

BACKGROUND

Stillbirth prevention is an international priority - risk prediction models could individualise care and reduce unnecessary intervention, but their use requires evaluation.

OBJECTIVES

To identify risk prediction models for stillbirth, and assess their potential accuracy and clinical benefit in practice.

SEARCH STRATEGY

MEDLINE, Embase, DH-DATA and AMED databases were searched from inception to June 2019 using terms relevant to stillbirth, perinatal mortality and prediction models. The search was compliant with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

SELECTION CRITERIA

Studies developing and/or validating prediction models for risk of stillbirth developed for application during pregnancy.

DATA COLLECTION AND ANALYSIS

Study screening and data extraction were conducted in duplicate, using the CHARMS checklist. Risk of bias was appraised using the PROBAST tool.

RESULTS

The search identified 2751 citations. Fourteen studies reporting development of 69 models were included. Variables consistently included were: ethnicity, body mass index, uterine artery Doppler, pregnancy-associated plasma protein and placental growth factor. For almost all models there were significant concerns about risk of bias. Apparent model performance (i.e. in the development dataset) was highest in models developed for use later in pregnancy and including maternal characteristics, and ultrasound and biochemical variables, but few were internally validated and none were externally validated.

CONCLUSIONS

Almost all models identified were at high risk of bias. There are first-trimester models of possible clinical benefit in early risk stratification; these require validation and clinical evaluation. There were few later pregnancy models but, if validated, these could be most relevant to individualised discussions around timing of birth.

TWEETABLE ABSTRACT

Prediction models using maternal factors, blood tests and ultrasound could individualise stillbirth prevention, but existing models are at high risk of bias.

Association between chorionicity and preterm birth in twin pregnancies: a systematic review involving 29 864 twin pregnancies

BACKGROUND

The perinatal mortality and morbidity among twins vary by chorionicity. Although it is considered that monochorionicity is associated with an increased risk of preterm birth in twin pregnancies, no systematic review exists evaluating this association.

OBJECTIVES

This systematic review was undertaken to assess the association between preterm birth and chorionicity in twin pregnancies.

SEARCH STRATEGY

We searched the electronic databases from January 1990 to July 2019 without language restrictions.

SELECTION CRITERIA

All studies on twin pregnancies where chorionicity and preterm birth were evaluated were included.

DATA COLLECTION AND ANALYSIS

Findings are reported as odds ratios with 95% confidence intervals. The estimates are pooled using random-effects meta-analysis.

MAIN RESULTS

From 13 156 citations, we included 39 studies (29 864 pregnancies). Monochorionicity was significantly associated with increased risk of preterm birth at ≤28, ≤32, ≤34 and <37 weeks in women asymptomatic and symptomatic for preterm labour (odds ratio [OR] 2.14, 95% CI 1.52-3.02, I²  = 46%, OR 1.55, 95% CI 1.27-1.89 I²  = 68%, OR 1.47, 95% CI 1.27-1.69, I²  = 60%, OR 1.66, 95% CI 1.43-1.93, I²  = 65%, respectively). Among those asymptomatic for preterm labour, significantly increased odds of preterm birth were seen for monochorionicity at gestations ≤34 weeks (OR 1.85, 95% CI 1.42-2.40, I²  = 25%) and <37 weeks (OR 1.75, 95% CI 1.22-2.53, I²  = 61%). Sensitivity analysis showed significantly increased odds of spontaneous preterm birth at ≤34 and <37 weeks for monochorionicity (OR 1.25, 95% CI 1.01-1.55, I²  = 0% and OR 1.41, 95% CI 1.13-1.78, I²  = 0%).

CONCLUSIONS

Monochorionicity is significantly associated with preterm birth at all gestations.

TWEETABLE ABSTRACT

In twin pregnancies, monochorionicity is associated with an increased risk of preterm birth at all gestations.

Virtual reality for acute pain in outpatient hysteroscopy: a randomised controlled trial

OBJECTIVE

To evaluate the effectiveness of virtual reality as a distraction technique in the management of acute pain and anxiety during outpatient hysteroscopy.

DESIGN

Parallel group, prospective randomised controlled trial.

SETTING

UK University Hospital.

METHODS

Forty consenting, eligible women were randomised to virtual reality intervention (immersive video content as a distraction method) or standard care during outpatient hysteroscopy from August to October 2018.

MAIN OUTCOME MEASURES

Pain and anxiety outcomes were measured as a numeric rating score (scale 0-10).

RESULTS

Compared with standard care, women with virtual reality intervention experienced less average pain (score 6.0 versus 3.7, mean difference 2.3, 95% CI 0.61-3.99, P = 0.009) and anxiety (score 5.45 versus 3.3, mean difference 2.15, 95% CI 0.38-3.92, P = 0.02).

CONCLUSION

Virtual reality was effective in reducing pain and anxiety during outpatient hysteroscopy in a mixed-methods randomised control trial. Its wide potential role in ambulatory gynaecological procedures needs further evaluation.

TWEETABLE ABSTRACT

Virtual reality can be used as a part of a multimodal strategy to reduce acute pain and anxiety in patients undergoing outpatient hysteroscopy.

Prediction of pre-eclampsia: review of reviews

OBJECTIVE

Primary studies and systematic reviews provide estimates of varying accuracy for different factors in the prediction of pre-eclampsia. The aim of this study was to review published systematic reviews to collate evidence on the ability of available tests to predict pre-eclampsia, to identify high-value avenues for future research and to minimize future research waste in this field.

METHODS

MEDLINE, EMBASE and The Cochrane Library including DARE (Database of Abstracts of Reviews of Effects) databases, from database inception to March 2017, and bibliographies of relevant articles were searched, without language restrictions, for systematic reviews and meta-analyses on the prediction of pre-eclampsia. The quality of the included reviews was assessed using the AMSTAR tool and a modified version of the QUIPS tool. We evaluated the comprehensiveness of search, sample size, tests and outcomes evaluated, data synthesis methods, predictive ability estimates, risk of bias related to the population studied, measurement of predictors and outcomes, study attrition and adjustment for confounding.

RESULTS

From 2444 citations identified, 126 reviews were included, reporting on over 90 predictors and 52 prediction models for pre-eclampsia. Around a third (n = 37 (29.4%)) of all reviews investigated solely biochemical markers for predicting pre-eclampsia, 31 (24.6%) investigated genetic associations with pre-eclampsia, 46 (36.5%) reported on clinical characteristics, four (3.2%) evaluated only ultrasound markers and six (4.8%) studied a combination of tests; two (1.6%) additional reviews evaluated primary studies investigating any screening test for pre-eclampsia. Reviews included between two and 265 primary studies, including up to 25 356 688 women in the largest review. Only approximately half (n = 67 (53.2%)) of the reviews assessed the quality of the included studies. There was a high risk of bias in many of the included reviews, particularly in relation to population representativeness and study attrition. Over 80% (n = 106 (84.1%)) summarized the findings using meta-analysis. Thirty-two (25.4%) studies lacked a formal statement on funding. The predictors with the best test performance were body mass index (BMI) > 35 kg/m² , with a specificity of 92% (95% CI, 89-95%) and a sensitivity of 21% (95% CI, 12-31%); BMI > 25 kg/m² , with a specificity of 73% (95% CI, 64-83%) and a sensitivity of 47% (95% CI, 33-61%); first-trimester uterine artery pulsatility index or resistance index > 90^th centile (specificity 93% (95% CI, 90-96%) and sensitivity 26% (95% CI, 23-31%)); placental growth factor (specificity 89% (95% CI, 89-89%) and sensitivity 65% (95% CI, 63-67%)); and placental protein 13 (specificity 88% (95% CI, 87-89%) and sensitivity 37% (95% CI, 33-41%)). No single marker had a test performance suitable for routine clinical use. Models combining markers showed promise, but none had undergone external validation.

CONCLUSIONS

This review of reviews calls into question the need for further aggregate meta-analysis in this area given the large number of published reviews subject to the common limitations of primary predictive studies. Prospective, well-designed studies of predictive markers, preferably randomized intervention studies, and combined through individual-patient data meta-analysis are needed to develop and validate new prediction models to facilitate the prediction of pre-eclampsia and minimize further research waste in this field. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome analysis

Objective

To determine the effects on the vaginal microbiota of an oral probiotic preparation administered from early pregnancy.

Design

Randomised, double blind, placebo‐controlled trial.

Setting

Four maternity units in the UK.

Population

Women aged 16 years or older recruited at 9–14 weeks' gestation.

Methods

Participants were randomly allocated to receive oral capsules of probiotic containing Lactobacillus rhamnosus GR‐1 and Lactobacillus reuteri RC‐14 each at 2.5 × 10⁹ colony‐forming units (CFUs) or placebo once daily from recruitment until the end of pregnancy.

Main outcome measure

Rates of bacterial vaginosis (BV, defined as Nugent score ≥7) at 18–20 weeks' gestation compared by logistic regression adjusted for possible confounders.

Results

The primary analysis included 78% (238/304) of participants who initially consented (probiotic group 123, placebo group 115). Of these participants, 95% (227/238) reported an intake of 93% or more of the required number of capsules. The rates of BV did not differ between groups at 18–20 weeks' gestation (15% (19/123) in the probiotic group vs. 9% (10/115) in the placebo group, adjusted odds ratio 1.82, 95% confidence interval 0.64–5.19). There were also no differences between the groups in the proportion of women colonised with the probiotic strains, Escherichia coli, group B streptococci or other vaginal microbiota. There were no differences in the alpha diversity or composition of the bacterial communities between or within the probiotic and placebo groups at 9–14 and 18–20 weeks’ gestation.

Conclusions

Oral probiotics taken from early pregnancy did not modify the vaginal microbiota.

Tweetable abstract

The oral probiotic preparation used in this study does not prevent BV in pregnant women.

The oral probiotic preparation used in this study does not prevent BV in pregnant women.

Serum ferritin thresholds for the diagnosis of iron deficiency in pregnancy: a systematic review

The aim of this review was to understand the landscape of serum ferritin in diagnosing iron deficiency in the aetiology of anaemia in pregnancy. Iron deficiency in pregnancy is a major public health problem leading to the development of anaemia. Reducing the global prevalence of anaemia in women of reproductive age is a 2025 global nutrition target. Bone marrow aspiration is the gold standard test for iron deficiency but requires an invasive procedure; therefore, serum ferritin is the most clinically useful test. We undertook a systematic search of electronic databases and trial registers from inception to January 2016. Studies of iron or micronutrient supplementation in pregnancy with pre‐defined serum ferritin thresholds were included. Two independent reviewers selected studies, extracted data and assessed quality. There were 76 relevant studies mainly of observational study design (57%). The most commonly used thresholds of serum ferritin for the diagnosis of iron deficiency were <12 and <15 ng mL⁻¹ (68%). Most primary studies provided no justification for the choice of serum ferritin threshold used, but 25 studies (33%) used thresholds defined by expert consensus in a guideline development process. There were five studies (7%) using a serum ferritin threshold defining iron deficiency derived from primary studies of bone marrow aspiration. Unified international thresholds of iron deficiency for women throughout pregnancy are required for accurate assessments of the global disease burden and for evaluating effectiveness of interventions addressing this problem.

Development of maternal and neonatal composite outcomes for trials evaluating management of late-onset pre-eclampsia

OBJECTIVE

Pre-eclampsia is associated with significant maternal and neonatal complications, and delivery is often expedited to minimise complications. For randomised trials evaluating interventions in women with late-onset (>34 weeks) mild to moderate pre-eclampsia, no single outcome has been identified to be the most clinically important. Existing composite outcomes with more than one clinically relevant endpoint to evaluate interventions in pre-eclampsia provide limited justification for selection of the components. Our objective was to develop robust, valid composite maternal and neonatal outcome measures for clinical trials evaluating interventions in women with late-onset mild and moderate pre-eclampsia.

STUDY DESIGN

A two-generational Delphi method was used to identify these clinically important maternal and neonatal outcomes. Composite outcomes were developed based on biological plausibility, independence from each other, frequency of occurrence and level of importance.

RESULTS

The final maternal composite outcome included maternal death, eclampsia, stroke or reversible ischaemic neurological deficit, pulmonary oedema, major obstetric haemorrhage, need for positive inotropic support, haemolysis, elevated liver enzymes and low platelets syndrome and placental abruption; and the neonatal composite outcome included neonatal death, respiratory distress syndrome needing ventilator support and neurological outcomes as cystic periventricular leukomalacia and grade III/IV intraventricular haemorrhage.

CONCLUSION

The composite outcomes developed will enable clinical trials to provide robust estimates on the effectiveness of the interventions in women with mild to moderate late onset pre-eclampsia to inform clinical practice. Caution is needed in the interpretation of composite outcomes due to variation in the importance of individual components.

Case report: cystic hygroma

BACKGROUND

Cystic hygroma (CH) is a congenital malformation of the lymphatic system. It most commonly presents in the neck, and aetiological factors include environmental and genetic factors.

CASE REPORT

A 13-year-old female presented with spontaneous dental pain affecting the maxillary left first and second permanent molar teeth. Medical history revealed a history of left sided cervico-facial-thoracic CH. She was diagnosed with periapical peridontitis and required extraction of both teeth. Clinical management was compromised by the CH involving the left face, neck, ear, tongue, larynx, oropharynx and mediastinum and circling the trachea and great vessels.

TREATMENT

Initial management included the placement of obtundant dressings for teeth number 26 and 27 with resolution of dental pain. Intensive prevention was instigated, and teeth number 16 and 17 were restored with composite resin under local analgesia (LA) without incident. Extraction of teeth number 26 and 27 was complicated by significant trismus and the unacceptably high risk associated with general anaesthesia, due to intubation difficulties. It proved impossible to achieve satisfactory local analgesia. Due to her difficult airway, it was decided to treat the patient with inhalational sedation, but administered in an operating theatre by a consultant anaesthetist, and teeth were extracted using articaine LA.

FOLLOW-UP

The patient coped well with this treatment, and was discharged home on the same day. Two year follow-up with intensive prevention showed improved oral health, with no new carious lesions detected.

CONCLUSION

This is the first report to our knowledge describing dental extractions in the immediate vicinity of a cystic hygroma. A potential management strategy and the difficulties of conventional methods in such patients are discussed.

Do sexual health staff know what patients want from services?

Although the 'patient provider partnership' is now supposed to be an integral part of modern clinical care, an assumption is often made by clinicians that they know what patients want from health services. Sexual health care is no different. In order to investigate the accuracy of this supposition, a survey was undertaken in February 2009 of all staff members working in the Department of Reproductive and Sexual Health (doctors, nurses and administrative staff) in Enfield. They were asked to predict what their patients' priorities were when accessing sexual health services. The results showed that nurses were the most accurate at anticipating what patients most valued, by correctly predicting their top three priorities (confidentiality, speed of service and rapid test results). Doctors were the least accurate and only predicted one of the top three patient priorities. These results are now being used locally to ensure that all members of the multidisciplinary team have input into the development of clinic guidelines and service design.

What do patients want most from sexual health services?

Changes to sexual health clinics have recently been driven by government waiting time targets. However, patients' needs and expectations should be equally important when making service alterations. This study sought to determine what patients valued most when attending an integrated sexual health clinic. During February 2009, 252 patients attending a sexual health clinic in outer London completed an anonymous questionnaire. The questionnaire asked for their views on different aspects of sexual health care. The results showed that the most highly valued aspects of care were confidentiality (18.47% of points allocated) followed by speed of service (13.1%) and rapid test results (12.12%). These aspects were more important than being seen within 48 hours (7.78%), technical expertise (6.26%) or other patient-centred aspects of care. These findings, which represent patients' views, have important implications for service design.

Benefit of preformed silos in the management of gastroschisis

Gastroschisis is traditionally managed by primary closure (PC) or delayed closure after surgical silo placement. Bedside insertion of preformed silos (PFS) and delayed closure has become more widespread, although its benefits remain unclear. To identify differences in outcome of infants managed with PFS compared with traditional closure (TC) techniques. Single-centre retrospective review of 53 consecutive neonates admitted between February 2000 and January 2006. Data expressed as median (range). Non-parametric statistical analysis used with P < 0.05 regarded as significant. Forty infants underwent TC and 13 had PFS and delayed closure. Median ventilation time in both groups was 4 days (P = 0.19) however this was achieved with higher mean airway pressures (MAPs) (day 0, 10 (5-16) versus 8 (5-10) cmH(2)O; P = 0.02) and inspired oxygen (40 (21-100) versus 30 (21-60)%; P = 0.03) in TC group. Urine output on day-1 of life was significantly higher in PFS group (1.1 (0.16-3.07) versus 0.45 (0-2.8) ml/kg/h; P = 0.02). Inotrope support was required in 17/40 (43%) of TC versus 0/13 (0%) in PFS (P < 0.01). After exclusion of infants with short bowel syndrome and/or intestinal atresia (n = 9), there was a shorter time to full enteral feeds in the TC group (22 (12-36) versus 27 (17-45); P = 0.07), although there was no difference in the period of parenteral nutrition (PN) (P = 0.1) or overall hospital stay (P = 0.34). No deaths or episodes of necrotizing enterocolitis occurred. The use of PFS for gastroschisis closure is associated with a reduction in pulmonary barotrauma, better tissue perfusion and improved early renal function, consistent with a reduction in abdominal compartment syndrome.

Mediastinitis and retropharyngeal abscess following delayed diagnosis of glass ingestion

Foreign body ingestion is a common occurrence in childhood. We report the outcome of an infant who swallowed a piece of glass. The absence of a foreign body on chest radiograph led to delayed diagnosis and then to the well documented complications of retropharyngeal abscess and mediastinitis. She was admitted to the paediatric intensive care unit a week after her initial presentation, subjected to multiple invasive and non-invasive procedures, and 6 weeks after her initial presentation to the accident and emergency department, was discharged back to her referring hospital having re-established oral feeds.

Some aspects of the biology and control using botanicals of the rice moth, Corcyra cephalonica (Stainton), on some pulses

The life cycle of Corcyra cephalonica was studied under ambient laboratory conditions (temperature range 27.5-30 degrees C and 60-73% r.h.) on groundnut, bambara groundnut and cowpea. The mean developmental period ranged from 33.2+/-0.2 to 45.3+/-1.8 days on whole, broken and powdered forms of the food media. Egg hatchability was found to be 83%, while adult longevity ranged from 1.5+/-0.5 to 11.9+/-1.3 days for males and 1.5+/-0.5 to 16.5+/-1.2 days for females. Sex ratio (male symbol:female symbol) of emerged adults ranged from 1:1 to 1:2.1. Mean fecundities ranged from 128+/-5 to 157+/-8 on the food media. In experiments to assess the insecticidal potential of three plant materials against C. cephalonica, Eichhornia crassipes powder showed a higher efficacy than both Citrus sinensis peel powder and the leaf powder of Chromolaena odorata at dosages of 0.5-2.0 g per 40 g of legume seed. At the higher dosage of 2.5 g, C. sinensis was more effective and reduced the population of C. cephalonica by half when compared to the population in control jars over a period of 1.5 months.

A mycological investigation of phane, an edible caterpillar of an emperor moth, Imbrasia belina

Phane worm (an edible larval stage of the emperor moth Imbrasia belina Westwood) is an important food source, and its harvesting is an economic activity in rural Botswana. When the larva is feeding on leaves and later during processing, phane gets contaminated with fungi from the leaves and soil. We examined 73 jars, each containing approximately 608 g (+/-0.25 g) of processed phane stored under laboratory conditions (temperature range 20 to 24 degrees C and 50 to 80% relative humidity) and combined intestinal contents of five phane squeezed into each of 74 Duran bottles for fungi. Ninety seven percent of 74 samples of intestinal contents and 57.5% of 73 laboratory-stored phane were positive for either molds and/or yeasts. Yeast population in intestinal contents ranged from 2 x 10(1) CFU/g to 5 x 10(3) CFU/g, whereas molds ranged from 1 x 10(1) CFU/g to 2 x 10(2) CFU/g. Laboratory-stored phane had a mold population of 1 x 10(2) CFU/g to 6 x 10(5) CFU/g. Species of Chaetomium 13.8%, Aspergillus 12.4%, Fusarium 5.5%, and Mucor racemosus 4.1% were the most prevalent in intestinal contents of phane, whereas Aspergillus 42.1%, Penicillium 33.9%, and Mucorales 5.7% were predominant in laboratory-stored phane. The important mycotoxigenic fungi A. flavus, A. parasiticus, A. ochraceus, P. aurantiogriseum, P. citrinum, and P. verrucosum were isolated mainly from the laboratory-stored phane. The genera isolated from both intestinal phane contents and laboratory-stored phane were Alternaria, Aspergillus, Chaetomium, Drechslera, Fusarium, Mucor, Phoma, and Penicillium, suggesting recontamination of phane during drying and storage.

Occurrence of aflatoxins, fumonisin B1, and zearalenone in foods and feeds in Botswana

Sorghum and maize form the main dietary staple foods in Botswana. Other products such as peanuts, peanut butter, phane (an edible larval stage of an emperor moth Imbrasia belina Westwood), and pulses (cowpeas and beans) are also widely used as food and for the manufacture of feeds. These important food and feed commodities were analyzed for the presence of aflatoxins, fumonisin B1, and zearalenone. Aflatoxins were detected in 40% of the samples analyzed. The concentration of total aflatoxins ranged from 0.1 to 64 microg/kg. The mean concentration ranged from 0.3 microg/kg in sorghum to 23 microg/kg in peanut butter. Peanut butter samples were the most contaminated (71%). No aflatoxins were detected in maize. Fumonisin B1 was detected in 36% of the samples. Maize samples were the most contaminated (85% of the samples) with the concentration ranging from 20 to 1,270 microg/kg. No fumonisin B1 was detected in peanuts, phane, and beans. Zearalenone was only found in 2.6% of the samples analyzed at 40 microg/kg. Aflatoxins were the most common toxins detected in foods and feeds in Botswana. However, fumonisin B1 was more prevalent in maize than aflatoxins or zearalenone.