Statistical and agent-based modelling of the transmissibility of different SARS-CoV-2 variants in England and impact of different interventions.

The English SARS-CoV-2 epidemic has been affected by the emergence of new viral variants such as B.1.177, Alpha and Delta, and changing restrictions. We used statistical models and the agent-based model Covasim, in June 2021, to estimate B.1.177 to be 20% more transmissible than the wild type, Alpha to be 50-80% more transmissible than B.1.177 and Delta to be 65-90% more transmissible than Alpha. Using these estimates in Covasim (calibrated 1 September 2020 to 20 June 2021), in June 2021, we found that due to the high transmissibility of Delta, resurgence in infections driven by the Delta variant would not be prevented, but would be strongly reduced by delaying the relaxation of restrictions by one month and with continued vaccination. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

Women with nausea and vomiting in pregnancy demonstrate worse health and are adversely affected by odours.

The objectives of this study were (1) to determine aversive stimuli that are related to nausea and vomiting in pregnancy (NVP); (2) to determine food and fluid intake in early pregnancy; and (3) to explore relationships between aversive stimuli and health measures. A total of 273 women in an antenatal setting completed a questionnaire survey, incorporating the Nausea and Vomiting in Pregnancy Instrument (NVPI); the General Health Questionnaire (GHQ); measures of perceived mood and illness; food and fluid intake; and open-ended questions relating to perceived aversive and helpful stimuli. Data was subjected to quantitative and qualitative analysis. A total of 57% of women reported aversive stimuli. Of these, the primary sense implicated was olfaction, with 72% reporting food smells. A number of women were affected by the odours of drinks (26%) and other products (31%). Women who were adversely affected by odours had higher severities of NVP, perceived illness and psychopathology scores on the GHQ. In conclusion, odour appears to be an important stimulus related to NVP, with perceived aversive smells related to the severity of nausea. Women severely affected by NVP demonstrated worse health. The role of olfaction in pregnancy and specifically in sufferers of severe NVP should be evaluated further.

Psychological health in early pregnancy: relationship with nausea and vomiting.

The psychological health of women in early pregnancy was investigated in a sample of 273 women (mean gestational age 12.8 weeks, SD=2.8) using the General Health Questionnaire (GHQ) and mood and illness perception visual analogue scales, and compared with the prevalence and severity of nausea and vomiting as measured using the Nausea and Vomiting in Pregnancy Instrument (NVPI). Using a cut-off of 4/5 for the GHQ, 50.5% of pregnant women were found to have potential psychiatric problems. However, perceived mental health and physical illness was significantly better than anticipated. The severity of nausea and vomiting correlated independently with GHQ subscales for somatic symptoms, social dysfunction, anxiety/insomnia and severe depression. The contradiction between high GHQ scored and high perceived wellbeing might be explained through cognitive processing. Nausea and vomiting in early pregnancy is associated with psychiatric morbidity. The causal relationship between the two conditions has not been established.

Development of an instrument to measure nausea and vomiting in pregnancy.

Severity of nausea, retching and vomiting was determined using a newly developed nausea and vomiting in pregnancy instrument (NVPI) in two groups of pregnant women at two gestational time periods. Participants at Time 1 (approximately gestational week 9), completed a postal questionnaire (N = 643) and those at Time 2 (approximately 13 weeks) completed the instrument at the clinic (N = 284). The three scale items forming the instrument had acceptable internal reliability (Time 1 alpha = 0.76; Time 2 alpha = 0.82). It was noted that approximately 60% of women did not vomit, approximately 30% experienced no retching, but 30-40% experienced nausea either all the time or more than once a day. The instrument may prove to be useful as a research tool to study nausea and vomiting in pregnancy.

Farmers' perceptions of the impacts of tsetse and trypanosomosis control on livestock production: evidence from southern Burkina Faso.

Interviews with all the households in the Agropastoral Zone (ZAP) of Yalé, southern Burkina Faso, were conducted in 1994 and again in 1997 to assess the impacts of a tsetse control programme implemented from 1994, using insecticide-impregnated targets and pour-on treatments of all cattle with deltamethrin 1%. In the absence of health and productivity monitoring, data were collected in single-visit surveys in order to generate quantitative estimates of relevant reproductive performance variables for cattle and to assess changes in the inputs used and outputs produced. The results indicate a 25% increase in herd size and an increase in the number of oxen from 0.1 to 1.1 per household; a reduction in mortality from 63.1% to 7.1% and reductions in the rates of abortions and stillbirth of 55.9% and 51.3%, respectively; and an increase in the rate of live births of 57.6% and in the milk yield from 0.2 to 2.2 litres/cow per day in the dry season. These results show the dramatic impacts that trypanosomosis control can have on Zebu cattle exposed to high tsetse challenge. Well-designed surveys can be a cost-effective way to obtain estimates of productivity impacts that can be used to simulate projections of herd growth and meat and milk production in herd models. While there are many confounding factors associated with farmers' perception of a gain in productivity, these estimates form a useful alternative to subjective assessments in modelling the economic benefits of tsetse and trypanosomosis control.

Dentistry for physically handicapped children in the International Year of the Child.

The dental profession has responded to the challenge of the increasing number of physically handicapped children. Originally, the emphasis was on how the physical disability prevented the delivery of dental treatment. Now, it is recognized that preventive care is the only answer to the problem. It is suggested that eventually all children, irrespective of their handicap, will be best treated in general dental practice.