The Effects of Nutrient Enrichment and Herbivore Abundance on the Ability of Turf Algae to Overgrow Coral in the Caribbean

Turf algae are multispecies communities of small marine macrophytes that are becoming a dominant component of coral reef communities around the world. To assess the impact of turf algae on corals, we investigated the effects of increased nutrients (eutrophication) on the interaction between the Caribbean coral Montastraea annularis and turf algae at their growth boundary. We also assessed whether herbivores are capable of reducing the abundance of turf algae at coral-algae boundaries. We found that turf algae cause visible (overgrowth) and invisible negative effects (reduced fitness) on neighbouring corals. Corals can overgrow neighbouring turf algae very slowly (at a rate of 0.12 mm 3 wk−1) at ambient nutrient concentrations, but turf algae overgrew corals (at a rate of 0.34 mm 3 wk−1) when nutrients were experimentally increased. Exclusion of herbivores had no measurable effect on the rate turf algae overgrew corals. We also used PAM fluorometry (a common approach for measuring of a colony's “fitness”) to detect the effects of turf algae on the photophysiology of neighboring corals. Turf algae always reduced the effective photochemical efficiency of neighbouring corals, regardless of nutrient and/or herbivore conditions. The findings that herbivores are not capable of controlling the abundance of turf algae and that nutrient enrichment gives turf algae an overall competitive advantage over corals together have serious implications for the health of Caribbean coral reef systems. At ambient nutrient levels, traditional conservation measures aimed at reversing coral-to-algae phase shifts by reducing algal abundance (i.e., increasing herbivore populations by establishing Marine Protected Areas or tightening fishing regulations) will not necessarily reduce the negative impact of turf algae on local coral communities. Because turf algae have become the most abundant benthic group on Curaçao (and likely elsewhere in the Caribbean), new conservation strategies are required to mitigate their negative impact on coral communities

The significance of mosquito saliva in arbovirus transmission and pathogenesis in the vertebrate host

Due to changes in climate, numerous mosquito species are continuously extending their geographical distributions, posing potential new public health threats as arbovirus infections emerge in these new areas. During probing and feeding on the vertebrate host, a mosquito can inject both arbovirus and saliva into the skin of the host. The presence of mosquito saliva in the host skin during arbovirus transmission contributes to high viral titers in the skin, enhanced viremia, and rapid dissemination of the virus to target organs. This enhanced phenotype effectuated by the presence of mosquito saliva in the skin can be partly ascribed to a polarization of the local immune balance towards a Th2 response, an increased permeability of the dermal endothelium, and the influx of virus-susceptible immune cells to the bite site. However, the complete identification and characterization of immunomodulatory salivary proteins from different mosquito species and the mechanisms by which these salivary proteins exert their effects synergistically or antagonistically remains to be further explored. Moreover, the effect of new virus-vector combinations on the outcome of arbovirus infection in a new host is limited. Here, we review the immunomodulatory effects of mosquito saliva in the skin and the proposed mechanisms by which mosquito saliva enhances arbovirus pathogenesis in the vertebrate host, and discuss potential differences between Aedes and Culex mosquito species, the main vectors for medically important arboviruses. Gaining more insight into the effect of mosquito saliva in the vector-virus-host triad aids in predicting the potential transmission risk and disease severity of emerging vector-borne diseases

Electromyographically recorded patellar reflex in normotensive pregnant women and patients with preeclampsia

ObjectiveTo define reference values of the patellar reflex in normotensive pregnant and postpartum women and to compare these with values in women with preeclampsia. DesignObservational study. SettingUniversity teaching hospital in the Netherlands. PopulationNormotensive non-pregnant women, pregnant women and preeclamptic women. MethodsIn normotensive pregnant women the patellar reflex was cross-sectionally recorded using surface electromyography at four time points during pregnancy and six to eight weeks postpartum. In non-pregnant normotensive women this was recorded once. Preeclamptic women were recorded during pregnancy and postpartum. Main outcome measuresLatency and amplitude of the compound muscle action potential of the patellar reflex. ResultsLatency and amplitude of the compound muscle action potential during normotensive pregnancies showed no changes compared with the non-pregnant state during reproductive age. Latency of the compound muscle action potential was increased in pregnancies with severe preeclampsia compared with normotensive pregnancies. These differences disappeared postpartum. ConclusionsDuring pregnancy, the patellar reflex can be assessed using surface electromyography. Latency and amplitude show no changes during normotensive pregnancies and are no different from the postpartum or non-pregnant values. In severely preeclamptic women, latency is increased. The clinical value of this is limited

Abandon of intramuscular administration of rabies immunoglobulin for post-exposure prophylaxis in the revised guidelines in the Netherlands in 2018: Cost and volume savings

The World Health Organization (WHO) issued an updated position paper on rabies in 2018, mainly focusing on simplification of vaccination schedules and use of rabies immunoglobulin (RIG). The maximum amount of RIG anatomically feasible should be infiltrated exclusively in and around the wound and will no longer be calculated solely based on body weight. We describe the practical guideline implementing the revised RIG policy in the Netherlands on how to determine the amount of RIG for local administration. We calculated savings achieved through the revised WHO policy. We used information from a national database including rabies consultations in the Netherlands and clinical information from a public health service, clinical practitioners and national data on the amount of distributed RIG. Between 2008 and 2019, 5,164 consultations were registered. The most frequently affected anatomical location was hand or leg (43%). Around 80% concerned minor injuries (< 2 cm). From January 2016 to end December 2019, 7,361 mL RIG were distributed for 1,042 possible rabies exposures (EUR 1.4 million). Since implementing the revised policy, the amount of RIG distributed per order has sharply decreased (59%). Infiltrating RIG only locally saved large quantities of human RIG (EUR 1.1 million during 4 years) in the Netherlands

Abandon of intramuscular administration of rabies immunoglobulin for post-exposure prophylaxis in the revised guidelines in the Netherlands in 2018: cost and volume savings.

The World Health Organization (WHO) issued an updated position paper on rabies in 2018, mainly focusing on simplification of vaccination schedules and use of rabies immunoglobulin (RIG). The maximum amount of RIG anatomically feasible should be infiltrated exclusively in and around the wound and will no longer be calculated solely based on body weight. We describe the practical guideline implementing the revised RIG policy in the Netherlands on how to determine the amount of RIG for local administration. We calculated savings achieved through the revised WHO policy. We used information from a national database including rabies consultations in the Netherlands and clinical information from a public health service, clinical practitioners and national data on the amount of distributed RIG. Between 2008 and 2019, 5,164 consultations were registered. The most frequently affected anatomical location was hand or leg (43%). Around 80% concerned minor injuries (< 2 cm). From January 2016 to end December 2019, 7,361 mL RIG were distributed for 1,042 possible rabies exposures (EUR 1.4 million). Since implementing the revised policy, the amount of RIG distributed per order has sharply decreased (59%). Infiltrating RIG only locally saved large quantities of human RIG (EUR 1.1 million during 4 years) in the Netherlands

The dinucleotide composition of the Zika virus genome is shaped by conflicting evolutionary pressures in mammalian hosts and mosquito vectors

Most vertebrate RNA viruses show pervasive suppression of CpG and UpA dinucleotides, closely resembling the dinucleotide composition of host cell transcriptomes. In contrast, CpG suppression is absent in both invertebrate mRNA and RNA viruses that exclusively infect arthropods. Arthropod-borne (arbo) viruses are transmitted between vertebrate hosts by invertebrate vectors and thus encounter potentially conflicting evolutionary pressures in the different cytoplasmic environments. Using a newly developed Zika virus (ZIKV) model, we have investigated how demands for CpG suppression in vertebrate cells can be reconciled with potentially quite different compositional requirements in invertebrates and how this affects ZIKV replication and transmission. Mutant viruses with synonymously elevated CpG or UpA dinucleotide frequencies showed attenuated replication in vertebrate cell lines, which was rescued by knockout of the zinc-finger antiviral protein (ZAP). Conversely, in mosquito cells, ZIKV mutants with elevated CpG dinucleotide frequencies showed substantially enhanced replication compared to wild type. Host-driven effects on virus replication attenuation and enhancement were even more apparent in mouse and mosquito models. Infections with CpG- or UpA-high ZIKV mutants in mice did not cause typical ZIKV-induced tissue damage and completely protected mice during subsequent challenge with wild-type virus, which demonstrates their potential as live-attenuated vaccines. In contrast, the CpG-high mutants displayed enhanced replication in Aedes aegypti mosquitoes and a larger proportion of mosquitoes carried infectious virus in their saliva. These findings show that mosquito cells are also capable of discriminating RNA based on dinucleotide composition. However, the evolutionary pressure on the CpG dinucleotides of viral genomes in arthropod vectors directly opposes the pressure present in vertebrate host cells, which provides evidence that an adaptive compromise is required for arbovirus transmission. This suggests that the genome composition of arbo flaviviruses is crucial to maintain the balance between high-level replication in the vertebrate host and persistent replication in the mosquito vector.</p

Factorial ANOVA results of the effects of neighbour type (CCA or turfalgae) and nutrient enrichment on turfalgal overgrowth.

<p>ns  =  not significant.</p

Overgrowth rates when turf algae are present (Turf) or absent, i.e., corals border crustose coralline algae (CCA).

<p>The treatment in which corals bordered CCA's served as “controls” for the turf algal treatment. The presence and absence of added nutrients is indicated by +Nut and -Nut respectively and the presence (+Hbv) or absence (-Hbv) of herbivores is indicated using the same methodology. Letters above the markers indicate significant groupings based on post-hoc analyses.</p