A Zika virus protein expression screen in Drosophila to investigate targeted host pathways during development

In the past decade, Zika virus (ZIKV) emerged as a global public health concern. Although adult infections are typically mild, maternal infection can lead to adverse fetal outcomes. Understanding how ZIKV proteins disrupt development can provide insights into the molecular mechanisms of disease caused by this virus, which includes microcephaly. In this study, we generated a toolkit to ectopically express ZIKV proteins in vivo in Drosophila melanogaster in a tissue-specific manner using the GAL4/UAS system. We used this toolkit to identify phenotypes and potential host pathways targeted by the virus. Our work identified that expression of most ZIKV proteins caused scorable phenotypes, such as overall lethality, gross morphological defects, reduced brain size and neuronal function defects. We further used this system to identify strain-dependent phenotypes that may have contributed to the increased pathogenesis associated with the outbreak of ZIKV in the Americas in 2015. Our work demonstrates the use of Drosophila as an efficient in vivo model to rapidly decipher how pathogens cause disease and lays the groundwork for further molecular study of ZIKV pathogenesis in flies.

A Zika virus protein expression screen in Drosophila to investigate targeted host pathways during development

In the past decade, Zika virus (ZIKV) emerged as a global public health concern. While adult infections are typically mild, maternal infection can lead to adverse fetal outcomes. Understanding how ZIKV proteins disrupt development can provide insights into the molecular mechanisms of symptoms caused by this virus including microcephaly. In this study, we generated a toolkit to ectopically express Zika viral proteins in vivo in Drosophila melanogaster in a tissue-specific manner using the GAL4/UAS system. We use this toolkit to identify phenotypes and host pathways targeted by the virus. Our work identified that expression of most ZIKV proteins cause scorable phenotypes, such as overall lethality, gross morphological defects, reduced brain size, and neuronal function defects. We further use this system to identify strain-dependent phenotypes that may contribute to the increased pathogenesis associated with the more recent outbreak of ZIKV in the Americas. Our work demonstrates Drosophila's use as an efficient in vivo model to rapidly decipher how pathogens cause disease and lays the groundwork for further molecular study of ZIKV pathogenesis in flies.

Drosophila functional screening of de novo variants in autism uncovers damaging variants and facilitates discovery of rare neurodevelopmental diseases

Individuals with autism spectrum disorder (ASD) exhibit an increased burden of de novo mutations (DNMs) in a broadening range of genes. While these studies have implicated hundreds of genes in ASD pathogenesis, which DNMs cause functional consequences in vivo remains unclear. We functionally test the effects of ASD missense DNMs using Drosophila through "humanization" rescue and overexpression-based strategies. We examine 79 ASD variants in 74 genes identified in the Simons Simplex Collection and find 38% of them to cause functional alterations. Moreover, we identify GLRA2 as the cause of a spectrum of neurodevelopmental phenotypes beyond ASD in 13 previously undiagnosed subjects. Functional characterization of variants in ASD candidate genes points to conserved neurobiological mechanisms and facilitates gene discovery for rare neurodevelopmental diseases.

306 Anterior Cruciate Ligament Graft Rupture: Analysis of Anteromedial Versus Trans-Tibial Portal Technique for Femoral Tunnel Placement in 473 Patients

Introduction

Correct femoral tunnel position in anterior cruciate ligament reconstruction (ACLR) is critical in obtaining good clinical outcomes. We aimed to delineate whether any difference exists between the anteromedial and trans-tibial portal femoral tunnel placement techniques on the primary outcome of ACLR, graft rupture.

Method

Adult patients (>18 years old) who underwent primary ACLR between January 2011 - January 2018 were identified and divided based on portal technique (anteromedial v trans-tibail). The primary outcome measure was graft rupture. Univariate analysis was used to delineate association between independent variables and outcome. Binary logistic regression was utilised to delineate odds ratios of significant variables.

Results

473 patients were analysed. Median age at surgery was 27 years old (range 18-70). 152/473 (32.1%) patients were anteromedial group compared to 321/473 (67.9%) trans-tibial. 25/473 (5.3%) patients sustained graft rupture. Median time to graft rupture was 12 months (IQR 9). A higher odd for graft rupture was associated with the anteromedial group, which trended towards significance (OR 2.03; 95% CI 0.90 - 4.56, p = 0.081).

Conclusions

There is no statistically significant difference in ACLR graft rupture rates when comparing anteromedial and trans-tibial portal technique for femoral tunnel placement. There was a trend towards higher rupture rates in the anteromedial portal group.

Compartmentalized oskar degradation in the germ plasm safeguards germline development

Partitioning of mRNAs into ribonucleoprotein (RNP) granules supports diverse regulatory programs within the crowded cytoplasm. At least two types of RNP granules populate the germ plasm, a cytoplasmic domain at the posterior of the Drosophila oocyte and embryo. Germ granules deliver mRNAs required for germline development to pole cells, the germ cell progenitors. A second type of RNP granule, here named founder granules, contains oskar mRNA, which encodes the germ plasm organizer. Whereas oskar mRNA is essential for germ plasm assembly during oogenesis, we show that it is toxic to pole cells. Founder granules mediate compartmentalized degradation of oskar during embryogenesis to minimize its inheritance by pole cells. Degradation of oskar in founder granules is temporally and mechanistically distinct from degradation of oskar and other mRNAs during the maternal-to-zygotic transition. Our results show how compartmentalization in RNP granules differentially controls fates of mRNAs localized within the same cytoplasmic domain.

Hepatitis A vaccination options for Australia

The epidemiology of hepatitis A is changing, with an increasing proportion of the population becoming susceptible to infection. The burden of hepatitis A is comparable to that of other vaccine-preventable diseases for which new vaccines are available. Options for vaccination include selective programmes for high-risk groups, which could involve screening prior to vaccination, or universal programmes for infants and/or adolescents. Selective programmes have been shown to be highly cost-effective if well implemented, but there is evidence that they might be poorly implemented. If a universal vaccination programme were considered for Australia, an infant programme, with doses at 18 months and 2 years, possibly with an additional adolescent programme, would be the recommended option. Universal hepatitis A vaccination for infants and/or adolescents is of comparable cost-effectiveness compared with other preventive strategies, but needs to be considered in the context of competing vaccination options.

Coverage of work related fatalities in Australia by compensation and occupational health and safety agencies

AIMS

To determine the levels of coverage of work related traumatic deaths by official occupational health and safety (OHS) and compensation agencies in Australia, to allow better understanding and interpretation of officially available statistics.

METHODS

The analysis was part of a much larger study of all work related fatalities that occurred in Australia during the four year period 1989 to 1992 inclusive and which was based on information from coroners' files. For the current study, State, Territory, and Commonwealth OHS and compensation agencies were asked to supply unit record information for all deaths identified by the jurisdictions as being due to non-suicide traumatic causes and which were identified by them as being work related, using whatever definitions the agencies were using at the relevant time. This information was matched to cases identified during the main study.

RESULTS

The percentage of working deaths not covered by any agency was 34%. Only 35% of working deaths were covered by an OHS agency, while 57% were covered by a compensation agency. The OHS agencies had minimal coverage of work related deaths that occurred on the road (to workers (8%) or commuters (3%)), whereas the compensation system covered these deaths better than those of workers in incidents that occurred in a workplace (65% versus 53%). There was virtually no coverage of bystanders (less than 8%) by either type of agency. There was marked variation in the level of coverage depending on the industry, occupation, and employment status of the workers, and the type of injury event involved in the incident.

CONCLUSIONS

When using data from official sources, the significant limitations in coverage identified in this paper need to be taken into account. Future surveillance, arising from a computerised National Coroners Information System, should result in improved coverage of work related traumatic deaths in Australia.

Cooperative transformation and coexpression of bovine papillomavirus type 1 E5 and E7 proteins

Productively infected bovine fibropapillomas were examined for bovine papillomavirus type 1 (BPV-1) E7 localization. BPV-1 E7 was observed in the cytoplasm of basal and lower spinous epithelial cells, coexpressed in the cytoplasm of basal cells with the E5 oncoprotein. E7 was also observed in nucleoli throughout the basal and spinous layers but not in the granular cell layer. Ectopic expression of E7 in cultured epithelial cells gave rise to localization similar to that seen in productive fibropapillomas, with cytoplasmic and nucleolar expression observed. Consistent with the coexpression of E7 and E5 in basal keratinocytes, BPV-1 E7 cooperated with E5 as well as E6 in an anchorage independence transformation assay. While E5 is expressed in both basal and superficial differentiating keratinocytes, BPV-1 E7 is only observed in basal and lower spinous epithelial cells. Therefore, BPV-1 E7 may serve to modulate the cellular response of basal epithelial cells to E5 expression.

Vaccine preventable diseases and vaccination coverage in Australia, 1993-1998

BACKGROUND

Since the introduction of childhood vaccination for diphtheria in 1932 and the widespread use of vaccines to prevent tetanus, pertussis (whooping cough) and poliomyelitis in the 1950s, deaths in Australia from vaccine preventable diseases (VPDs) have declined by more than 99%. It is important, however, that the downward trend in morbidity and mortality from VPDs is maintained and carefully monitored, and that changes are interpreted in relation to vaccination coverage.

AIM

This report aimed to bring together three national sources of routinely collected data on the morbidity and mortality (notifications, hospitalisations and deaths) from VPDs during the period 1993-1998 for the 8 diseases then on the routine childhood vaccination schedule, and for 4 other diseases potentially preventable by childhood vaccination. It also examined vaccination coverage for the same period.

METHODS

Data sources included notifications from the National Notifiable Diseases Surveillance System (NNDSS), hospitalisation data from the Australian Institute of Health and Welfare (AIHW) National Hospital Morbidity Database, deaths from the Australian Bureau of Statistics (ABS) Causes of Death Collection and vaccination coverage according to the Australian Childhood Immunisation Register (ACIR). All data sources were expected to have some limitations, the most important being under-reporting for notifications and vaccination encounters, and coding errors in the hospital morbidity data.

RESULTS

Notifications for the 8 diseases covered by the routine schedule declined by 42%, from an average of 11,537 cases each year in 1993-1997 to 6700 in 1998, and hospitalisations fell by 12%, from an average of 1745 per year to 1536 in 1997/1998, while deaths remained unchanged at 7 each year over the period of review (Table 1). Tetanus caused 1 or 2 of the deaths each year. However, 6 of the 7 deaths in 1997 were in infants during a major outbreak of pertussis. Pertussis caused most of the notifications, hospitalisations and deaths during the review period. While most of these were in children, 46% of the notifications and 13% of the hospitalisations occurred in persons aged 15 years or more. There were notable declines in the numbers of notifications of invasive Haemophilus influenzae type b (Hib) disease in children under 5 years of age (77%), measles (87%) and rubella (75%), and there were no notifications of diphtheria or poliomyelitis. Vaccination coverage estimated using ACIR data increased during the review period. Coverage for the first 3 doses of diphtheria, tetanus, pertussis and Hib vaccines, assessed at 1 year of age, increased from 75% to 85%, while coverage for measles-mumps-rubella (MMR) vaccine, assessed at 2 years of age, increased from 83% to 86%. It is likely that these data underestimated coverage by 5-10%, and that the increase in coverage partly reflected better reporting to the ACIR by providers.

L20B cells simplify culture of polioviruses from clinical samples

Culture of polioviruses from clinical samples is the gold-standard method for virological surveillance in the world-wide initiative to eradicate wild-type polioviruses. Two poliovirus-sensitive cell lines of human origin were used originally by the laboratories of the World Health Organisation (WHO) global poliovirus network. However, the cell lines used, Hep2 and RD, also support cytopathic growth of a variety of non-poliovirus enteroviruses. This can make detection of polioviruses in samples with mixtures of viruses difficult and time consuming. The development of mouse cell lines that express the gene for the human cellular receptor for polioviruses allows selective poliovirus culture, because very few non-poliovirus enteroviruses grow in these murine cells. A WHO Collaborative Study was initiated to test one such cell line, L20B, and to compare under routine conditions the sensitivity and selectivity of L20B cells against RD and Hep2 cells. Five laboratories in countries endemic or recently endemic for wild polioviruses participated. A total of 425 samples were tested prospectively in all three cell lines and there was a clear and consistent trend for greater sensitivity for polioviruses in L20B cells. Overall, 148/160 polioviruses were detected in L20B cells compared with 89/160 in RD and 98/ 160 in Hep2. In part, this finding was due to detection in L20B cells of polioviruses from samples that also contained non-poliovirus enteroviruses in which the poliovirus was masked in RD or Hep2 cells. However, L20B cells were also significantly more sensitive for poliovirus than either RD or Hep2 cells in three of the five study laboratories. The L20B cells were completely selective for polioviruses, as 0/89 wild type non-poliovirus enteroviruses produced cytopathic effect in L20B cells. Finally, L20B cells provided a diagnosis of poliovirus infection in the same time as RD and Hep2 cells from samples that contained poliovirus only, but substantially more quickly for samples that contained another enterovirus. Taken together, these data indicate that L20B cells simplify primary diagnosis of poliovirus from clinical samples and as a result they have been introduced for routine use by laboratories of the WHO global poliovirus network.

Health status and exposure of workers at a pilot brown coal liquefaction plant in Australia, 1985-1991

In 1985, Brown Coal Liquefaction (Victoria) Pty Ltd (BCLV) commenced operation of a pilot plant that investigated the feasibility of producing oil from brown coal. The plant operated for five years. This study aimed to use exposure and health information routinely collected by the company to characterize various health parameters of the workforce and to investigate whether any adverse health measures were exposure-related. About 1680 persons were employed at some time or other by BCLV, and the primary study population consisted of 408 workers who had a medical examination at the end of employment and who consented to being in an epidemiological study. Reported photosensitivity was associated with higher cumulative skin exposure (RR = 1.85; 95% CI = 1.22-2.78), with an exposure-response relationship of increasing risk with increasing skin exposure being suggested. There was no consistent evidence that chemical exposure at BCLV had any negative effect on the haematological, biochemical, endocrine or lung function of workers at the plant. However, the maximum follow-up period of less than eight years limits the ability of the study to detect any emerging chronic effects.

Sylvatic yellow fever activity in Trinidad, 1988-1989

Of a total of 18,068 mosquitoes (361 pools) collected in south-eastern Trinidad forests from December 1988 to May 1989, 47 species belonging to 14 genera were identified. Five yellow fever virus isolates were made from Haemagogus janthinomys and one from Sabethes chloropterus. All the other pools of mosquitoes examined were negative for the virus. The mosquito isolates were made in December and January. In addition, in late February and early March, 2 infected howler monkeys (Alouatta sp.) were detected. Since March, despite continued surveillance, no yellow fever virus has been detected in mosquitoes or monkeys. There has been no reported human infection.

An outbreak of acute flaccid paralysis in Jamaica associated with echovirus type 22

An outbreak of acute flaccid paralysis in Jamaica in 1986 associated with echovirus type 22 is described. Six patients aged 1 to 27 years developed acute onset of severe flaccid paralysis, with inability to walk. Three cases had facial weakness, four required intensive care with assisted ventilation, and two died. Echovirus type 22 was isolated from the stool of two patients who showed a significant increase in antibody titre. Echovirus type 22 was also isolated from the stool of another patient who had aseptic meningitis without any neurological deficit. There was no evidence of poliovirus infection in any of these patients, most of whom were fully immunized. Of the four surviving cases with flaccid paralysis, three had residual weakness in their lower limbs and walked with an abnormal gait 3 years after the acute paralytic attack. This is the first report in the literature of acute flaccid paralysis associated with type 22 echovirus.

Polio immunization and serological status in children and adolescents in Jamaica (1985)

A survey of immunization status and serological immunity to polio was carried out in 5 parishes in Jamaica in 1985. A sample of 2,506 children and adolescents aged 1-19 years was chosen by selecting clusters of children in enumeration districts (EDs) in each parish from the 1980 Census. Immunization status was verified by examining immunization records. Serological assay for antibodies to Polio Types 1, 2, and 3 was done. A positive neutralization test at dilution of 1:8 was taken as immunity to the polio virus. Of the 1,819 children whose immunization status was confirmed, coverage with 3 or more doses of oral polio vaccine was highest in the 1-4 year age group with 79.7% and lowest in the 15-19-year age group with 37.4%. Of the 2,506 children 81.4%, 94.7% and 72.3% were seropositive for Polio Types 1, 2 and 3 respectively. There was a significant difference in the prevalence of seropositives between individuals with and those without a history of vaccinations. No urban/rural or sex differences were noted. The study indicated a higher level of immunization status than previous surveys and a high level of serological immunity to polio.

Hemolysis, elevated liver enzymes, and low platelet count syndrome: nursing care of the critically ill obstetric patient

Although patients with severe preeclampsia and eclampsia are infrequently admitted to critical care areas, it is important that the critical care nurse be aware of the HELLP syndrome. The case presentations demonstrated hemolysis, liver dysfunction, and abnormal platelet consumption. Knowledge of the clinical and laboratory findings will assist in nursing assessment and intervention for these critically ill obstetric patients.

Natural Transovarial Transmission of Dengue 4 Virus in Aedes Aegypti in Trinidad

The isolation of dengue 4 virus from adult Aedes aegypti, reared from eggs collected in nature, is reported for the first time. From the locality where the isolate was made, 25 pools consisting of 1,848 Ae. aegypti reared from eggs were processed. In this study, 10 different localities were sampled and a total of 10,957 Ae. aegypti adults, collected as eggs or larvae in nature, were processed for virus isolation. From a total of 158 mosquito pools tested, one recovery of dengue 4 virus was made. The isolation of dengue 4 virus from this field-collected material gives further evidence that transovarial transmission of dengue viruses occurs in nature.

The reconstitution of living skin

A living-skin equivalent useful as a skin replacement and as a model system for basic studies has been fabricated and tested extensively. It consists of two components: (1) a dermal equivalent made up of fibroblasts in a collagen matrix that is contracted and modified by the resident cells, and (2) an epidermis that develops from keratinocytes "plated" on the dermal equivalent. A multilayered keratinizing epidermis with desmosomes, tonofilaments, and hemidesmosomes forms. Basement lamella formation occurs within 2 weeks in vitro when rat cells are used. With human cells, crypt or pseudofollicular morphogenesis is observed in vitro within 3 weeks after plating cells on the dermal equivalent. Autografts and isografts of rat-skin equivalents made with cultured cells from biopsies are rapidly vascularized, block wound contraction, and persist essentially for the lifespan of the host. Seven to 9 days after grafting, donor cells become activated biosynthetically and mitotically. By 1 year, the dermal population decreases to a normal level and the matrix has been extensively remodeled. The grafts remain free of hair and sebaceous glands. Grafts to rats have been in place for over 2 years. Now, allografts of dermal equivalents have been made across a major histocompatibility barrier and are not rejected. The persistence of cellular elements of the grafts is monitored by use of a genetic marker. Challenge of the allograft with a second skin-equivalent graft after 1 month does not result in rejection of the original graft or of the second skin-equivalent graft. We propose that allografts of tissue equivalents are tolerated because cells with class II antigens are selected against during in vitro cultivation and are excluded from the graft. Thus the fabrication of skin-equivalent tissues or of other equivalent tissues with parenchymal cells that do not bear class II antigens may render transplants of such tissues immunologically acceptable despite the presence of allogeneic cells. The capacity to graft across major histocompatibility barriers using living tissue equivalents may have important clinical significance.

Regulation of proliferation of fibroblasts of low and high population doubling levels grown in collagen lattices

While IMR 90 and AG 1519 fibroblasts of low and high population doubling levels grow to confluency when plated on plastic surfaces, they cease to divide within four days when incorporated into collagen lattices. Growth inhibition in the lattices is not due to exhaustion of the medium or isotope, or to contact inhibition; nor is it due to impermeability of the lattice to the materials in the medium. While cells in a lattice arrest in G0, this state is reversible when cells are permitted to leave the lattice and populate a plastic substrate. We conclude that fibroblasts in tissue-like lattices may be responsive to some of the same controls as cells in connective tissues.

Development and use of a living skin equivalent

We have developed a living skin equivalent, which serves as a skin substitute in experimental animals. On application it is rapidly vascularized, it inhibits wound contraction, and it is immunologically tolerated and persists for as long as it is allowed to remain in place. It comes to resemble normal skin, although it lacks secondary derivatives, the cells for which may in time be available for incorporation into the fabricated tissue.

Serological evidence of dengue virus activity in children on the Northern Leeward Islands (Netherlands Antilles)

An arbovirus serologic survey of school children on the Northern Leeward Islands (Saba, St. Eustatius and St. Maarten) using haemagglutination inhibition (HI) detected a high proportion of reactors to dengue types 1,2, and 3. Analysis in relation to age showed an increasing proportion to be positive with increasing age. The results of an all-age survey on St. Eustatius 1970 led to the hypothesis of possible dengue serotype 1 activity on St. Eustatius around 1900, whilst it is thought that dengue type 2 was endemic at other times. In view of the continuous high endemic dengue activity the (re)-appearance of dengue serotype 1 next to type 2 and 3 may be the prelude to the occurrence of the dengue shock syndrome.