Summary During mammalian pregnancy, the placenta acts as a barrier between the maternal and fetal compartments. The recently observed association between Zika virus (ZIKV) infection during human pregnancy and fetal microcephaly and other anomalies suggests that ZIKV may bypass the placenta to reach the fetus. This led us to investigate ZIKV infection of primary human trophoblasts (PHT), which are the barrier cells of the placenta. We discovered that PHT cells from full-term placentas are refractory to ZIKV infection. In addition, medium from uninfected PHT cells protects non-placental cells from ZIKV infection. PHT cells constitutively release the type III interferon (IFN) IFNλ1, which functions in both a paracrine and autocrine manner to protect trophoblast and non-trophoblast cells from ZIKV infection. Our data suggests that for ZIKV to access the fetal compartment, it must evade restriction by trophoblast-derived IFNλ1 and other trophoblast-specific antiviral factors and/or use alternative strategies to cross the placental barrier.

This article describes a school-based mental health service established to help psychologically distressed refugee pupils. The primary school involved was situated in an inner London borough and had a high proportion of refugee and immigrant children. Teachers identified refugee pupils with psychological difficulties and referred them to an outreach mental health worker who provided treatment on the school site. In addition to clinical interview the strengths and difficulties questionnaire was used as an assessment and outcome measure. In total 14 children (12 boys) were referred to the project. The children had been exposed to high levels of past violence and losses, and experienced ongoing socioeconomic adversity. The children mostly had disorders related to these adversities, but a small number also appeared to have specific learning or scholastic difficulties. The difficulties mostly presented in the class as inattention and over-activity. A range of psychological and family interventions were offered, which included seeing the teachers initially, the children alone and relatives. Overall children were helped by the intervention with a reduction in SDQ scores (21.3 to 15.7) and some children showed dramatic benefit. This model seemed acceptable to the children, families and school. The implications of the project are discussed.

Neurotropic viral infections are significant sources of global morbidity and mortality. The blood-brain barrier (BBB) is composed in part of a layer of microvascular endothelial cells and functions to restrict viral access to the brain. In vitro models that recapitulate many of the properties of the human BBB endothelium are lacking, particularly with respect to the unique cellular and immunological mechanisms by which these cells restrict viral infections of the brain. Here, we developed a three-dimensional cell culture model that recapitulates many of the morphological and functional properties of the BBB microvasculature and apply this model to the study of RNA virus infections. The model we describe can therefore be used to study a variety of aspects of BBB physiology, including the mechanisms by which viruses might access the CNS, and could be used for the development and screening of antiviral therapeutics to limit this important step in viral pathogenesis.

Macrophages and other immune cells are important contributors to obesity‐associated inflammation; however, the cellular identities of these specific populations remain unknown. In this study, we identified individual populations of myeloid cells found in mouse epididymal/visceral adipose tissue by single‐cell RNA sequencing, immunofluorescence, and flow cytometry. Multiple canonical correlation analysis identified 11 unique myeloid and myeloid‐associate cell populations. In obese mice, we detected an increased percentage of monocyte‐derived pro‐inflammatory cells expressing Cd9 and Trem2, as well as significantly decreased percentages of multiple cell populations, including tissue‐resident cells expressing Lyve1, Mafb, and Mrc1. We have identified and validated a novel myeloid/macrophage population defined by Ly6a expression, exhibiting both myeloid and mesenchymal characteristics, which increased with obesity and showed high pro‐fibrotic characteristics in vitro. Our mouse adipose tissue myeloid cell atlas provides an important resource to investigate obesity‐associated inflammation and fibrosis.

What are coliform bacteria? COLIFORM is a 'catch all' term used to describe several species of lactose fermenting bacilli which inhabit the gut. The most commonly encountered is Escherichia coli and approximately 80 per cent of coliform isolates tested at the National Institute for Research in Dairying are E coli. Other coliform species implicated in bovine mastitis include Klebsiella pneumoniae, K oxytoca, Enterobacter cloacae, E aerogenes and Citrobacter freundii. All are 'gut associated' but some, notably K pneumoniae and Enterobacters, may be free-living in forest environments or soil and be introduced into a dairy herd with wood products used for cattle litter. When grown on sheep or calf blood agar, the usual medium for examination of milk samples, colonies 3 to 4 mm in diameter are produced after overnight incubation. Mastitis strains of E coli are usually non-haemolytic and the colonies tend to be a grey colour. Klebsiella and Enterobacter species are most often a green-brown colour by reflected light. Confirmation of the identification is most easily achieved by streaking the organism onto MacConkeys agar or inoculating into a tube of MacConkeys broth. After incubation at 30°C to 37°C pink colonies will appear on the plate or acid and gas will be produced in the broth. Although most E coli will produce the acid and gas reaction at 45°C this is not the case for some other coliform species. Further differentiation into species can be achieved with a range of biochemical tests but is of little clinical significance under most circumstances. Epidemiological studies show that many strains may produce mastitis in a single herd, reflecting the various strains present in the gut and the environment. The only prerequisite for udder pathogenicity of a coliform is resistance to the bactericidal activity of normal bovine serum. Unfortunately, some 80 per cent of environmental strains of E coli are resistant and, therefore, potentially pathogenic. Some coliforms, including E coli, are motile and may be toxigenic. Exotoxins can be elaborated, for example, the enterotoxins. The lipopolysaccharide element of the cell wall, termed endotoxin, is also highly toxic for the bovine. How common is coliform mastitis? Comparisons of the statistics relating to the incidence of udder infection can be misleading because of variations in the size or distribution of the population studied or the diagnostic methods employed. However, trends can be detected if suitable bench mark studies are examined. Coliform mastitis can be examined from two viewpoints: the proportion of quarters which are infected at a given time (ie, level of infection) or, more significantly, the frequency Ecolion blood agar from a mastitis case (left) and the characteristic reaction of Ecolion MacConkey's agar (centre) or in MacConkey's broth (right)