Rates of asymptomatic respiratory virus infection across age groups.

Respiratory viral infections are a leading cause of disease worldwide. A variety of respiratory viruses produce infections in humans with effects ranging from asymptomatic to life-treathening. Standard surveillance systems typically only target severe infections (ED outpatients, hospitalisations, deaths) and fail to track asymptomatic or mild infections. Here we performed a large-scale community study across multiple age groups to assess the pathogenicity of 18 respiratory viruses. We enrolled 214 individuals at multiple New York City locations and tested weekly for respiratory viral pathogens, irrespective of symptom status, from fall 2016 to spring 2018. We combined these test results with participant-provided daily records of cold and flu symptoms and used this information to characterise symptom severity by virus and age category. Asymptomatic infection rates exceeded 70% for most viruses, excepting influenza and human metapneumovirus, which produced significantly more severe outcomes. Symptoms were negatively associated with infection frequency, with children displaying the lowest score among age groups. Upper respiratory manifestations were most common for all viruses, whereas systemic effects were less typical. These findings indicate a high burden of asymptomatic respiratory virus infection exists in the general population.

Ethephon induced oxidative stress in the olive leaf abscission zone enables development of a selective abscission compound.

BACKGROUND: Table olives (Olea europaea L.), despite their widespread production, are still harvested manually. The low efficiency of manual harvesting and the rising costs of labor have reduced the profitability of this crop. A selective abscission treatment, inducing abscission of fruits but not leaves, is crucial for the adoption of mechanical harvesting of table olives. In the present work we studied the anatomical and molecular differences between the three abscission zones (AZs) of olive fruits and leaves. RESULTS: The fruit abscission zone 3 (FAZ3), located between the fruit and the pedicel, was found to be the active AZ in mature fruits and is sensitive to ethephon, whereas FAZ2, between the pedicel and the rachis, is the flower active AZ as well as functioning as the most ethephon induced fruit AZ. We found anatomical differences between the leaf AZ (LAZ) and the two FAZs. Unlike the FAZs, the LAZ is characterized by small cells with less pectin compared to neighboring cells. In an attempt to differentiate between the fruit and leaf AZs, we examined the effect of treating olive-bearing trees with ethephon, an ethylene-releasing compound, with or without antioxidants, on the detachment force (DF) of fruits and leaves 5 days after the treatment. Ethephon treatment enhanced pectinase activity and reduced DF in all the three olive AZs. A transcriptomic analysis of the three olive AZs after ethephon treatment revealed induction of several genes encoding for hormones (ethylene, auxin and ABA), as well as for several cell wall degrading enzymes. However, up-regulation of cellulase genes was found only in the LAZ. Many genes involved in oxidative stress were induced by the ethephon treatment in the LAZ alone. In addition, we found that reactive oxygen species (ROS) mediated abscission in response to ethephon only in leaves. Thus, adding antioxidants such as ascorbic acid or butyric acid to the ethephon inhibited leaf abscission but enhanced fruit abscission. CONCLUSION: Our findings suggest that treating olive-bearing trees with a combination of ethephon and antioxidants reduces the detachment force (DF) of fruit without weakening that of the leaves. Hence, this selective abscission treatment may be used in turn to promote mechanized harvest of olives.

Bacterial vaginosis in early pregnancy is associated with low birth weight and small for gestational age, but not with spontaneous preterm birth: a population-based study on Danish women.

OBJECTIVE: To analyze the association between bacterial vaginosis (BV) in early pregnancy and preterm birth, low birth weight (LBW) and small for gestational age (SGA) in a Danish population. METHODS: A geographically defined population-based prospective study of Danish-speaking pregnant women over18 years of age enrolled before week 24 and followed until delivery. BV was diagnosed by Amsel's clinical criteria at enrolment. RESULTS: At enrolment, 13.7% had BV. BV was not associated with an increased risk of spontaneous preterm birth (crude OR 0.8 (0.5-1.5)). Nulliparity was found to affect birth weight to such a degree that this variable was used for stratification. In nulliparous women BV was associated with LBW (adj. OR 4.3 (1.5-12)) and SGA (adj. OR 1.6 (0.7-3.1)) compared to nulliparous without BV. No such associations were seen for multiparous women with BV. CONCLUSIONS: BV was not associated with spontaneous preterm birth, but was associated with both LBW and SGA in nulliparous women.

Acquisition and elimination of bacterial vaginosis during pregnancy: a Danish population-based study.

OBJECTIVES: the aim was to examine factors associated with acquisition and elimination of bacterial vaginosis in pregnancy. METHODS: a group of 229 pregnant women were randomly selected from a population-based prospective cohort study of 2927. They were examined at enrollment (mean gestational weeks 16w+0d) and again in mid-third trimester (mean gestational age 32w+3d). MEASURES: BV (Amsel's clinical criteria), microbiological cultures of the genital tract and questionnaire data. RESULTS: BV prevalence decreased from 17% in early second trimester to 14% in mid-third trimester due to a tenfold higher elimination rate (39%) than incidence rate (4%). Heavy smokers (>10/d) in early pregnancy were at increased risk (5.3[1.1-25]) for the acquisition of BV during pregnancy, as were women receiving public benefits (4.8[1.0-22]), having a vaginal pH above 4.5(6.3[1.4-29]) or vaginal anaerobe bacteria (18[2.7-122]) at enrollment. A previous use of combined oral contraceptives was preventive for the acquisition of BV (0.2[0.03-0.96]). Elimination of BV in pregnancy tended to be associated with a heavy growth of Lactobacillus(3.2[0.8-13]) at enrollment. CONCLUSIONS: acquisition of BV during pregnancy is rare and is associated with smoking, while the presence of anaerobe bacteria and a vaginal pH >4.5 are interpreted as steps on a gradual change towards BV. In the same way heavy growth of Lactobacillus spp in early pregnancy may be an indicator of women on the way to eliminate BV.

Five challenges in evolution and infectious diseases.

Evolution is a key aspect of the biology of many pathogens, driving processes ranging from immune escape to changes in virulence. Because evolution is inherently subject to feedbacks, and because pathogen evolution plays out at scales ranging from within-host to between-host and beyond, evolutionary questions provide special challenges to the modelling community. In this article, we provide an overview of five challenges in modelling the evolution of pathogens and their hosts, and point to areas for development, focussing in particular on the issue of linking theory and data.

Risk factors for bacterial vaginosis in pregnancy: a population-based study on Danish women.

BACKGROUND: No larger population-based study of bacterial vaginosis in pregnancy has previously been available. The objective of this study was to examine risk factors for bacterial vaginosis in pregnancy. DESIGN: From a prospective population-based cohort of 3,596 eligible pregnant women, 2,927 (81.4%) completed the study. METHODS: Women were asked to participate in this study at their first prenatal visit at 17 gestational weeks (range 7 + 3 - 24 + 0). Samples from the genital tract were taken at enrollment. Bacterial vaginosis was determined by Amsel's clinical criteria (3 out of 4: pH > 4.5, homogenous discharge, clue cells, and positive amine test). Data were collected from three questionnaires completed during the second and third trimesters and correlated with the diagnosis of bacterial vaginosis. Crude and adjusted relative risks (reproductive, medical, behavioral, sexual, and sociodemographic factors) were computed. RESULTS: At enrollment, bacterial vaginosis was diagnosed in 13.7% of Danish pregnant women. Significant risk factors for bacterial vaginosis were: daily coitus (adjusted relative risk 2.09 [1.43-3.04]), being single (1.76 [1.21-2.56]), smoking more than 10 cigarettes daily at conception (1.59 [1.29-1.93]), previous genital infection with Chlamydia trachomatis or Neisseria gonorrhoeae (1.39 [1.07-1.79]), and consuming 2 or more drinks per week (1.33 [1.02-1.74]) after control for confounding factors. CONCLUSION: In pregnancy, women who have daily coitus, are single, smokers, with a previous sexually transmitted disease, or with high alcohol consumption in pregnancy are at increased risk for bacterial vaginosis. Information on these risk factors may be important when planning preventive and treatment strategies of bacterial vaginosis in pregnancy.

[Mycoplasma genitalium--a new challenge in sexually transmitted diseases]. / Mycoplasma genitalium--en ny udfordring i seksuelt overført infektion.

Although Mycoplasma genitalium was described 20 years ago, the knowledge concerning it is still limited. The publications in the area are surprisingly few in number, especially considering that the pathogen is rather common and has been connected with a number of different urogenital diseases. The PCR technique has made it possible to perform investigations on a large scale, which might elucidate the pathogenic role of M. genitalium in the urogenital tract. However, it seems well established that M. genitalium causes non-gonococcal urethritis (NGU). The mycoplasma behaves almost identically to Chlamydia trachomatis with respect to routes of infection and inflammatory response, but no further relationship between the two organisms seems obvious. M. genitalium is believed to produce urethritis with almost the same frequency as C. trachomatis. In the female genital tract, M. genitalium is strongly incriminated as a primary cause of cervicitis, endometritis and salpingitis, the latter complicated by tubal damage. The role of the organisms in epididymitis, prostatitis and neonatal infections is unclear. In the case of urethritis and upper genital tract infections in the female, it is recommended to test for M. genitalium using molecular biological assays and in the event of a positive result institute antimicrobial therapy.