Phaeocystis: A Global Enigma.

The genus Phaeocystis is globally distributed, with blooms commonly occurring on continental shelves. This unusual phytoplankter has two major morphologies: solitary cells and cells embedded in a gelatinous matrix. Only colonies form blooms. Their large size (commonly 2 mm but up to 3 cm) and mucilaginous envelope allow the colonies to escape predation, but data are inconsistent as to whether colonies are grazed. Cultured Phaeocystis can also inhibit the growth of co-occurring phytoplankton or the feeding of potential grazers. Colonies and solitary cells use nitrate as a nitrogen source, although solitary cells can also grow on ammonium. Phaeocystis colonies might be a major contributor to carbon flux to depth, but in most cases, colonies are rapidly remineralized in the upper 300 m. The occurrence of large Phaeocystis blooms is often associated with environments with low and highly variable light and high nitrate levels, with Phaeocystis antarctica blooms being linked additionally to high iron availability. Emerging results indicate that different clones of Phaeocystis have substantial genetic plasticity, which may explain its appearance in a variety of environments. Given the evidence of Phaeocystis appearing in new systems, this trend will likely continue in the near future.

The question of the early diagnosis of asymptomatic and subpatent malaria in pregnancy: Implications for diagnostic tools in a malaria endemic area.

Objectives: Malaria in pregnancy (MIP) is a major healthcare challenge in low-income countries with high malaria endemicity. Early but accurate diagnosis and appropriate treatment is the hallmark of preventing disease progression/adverse outcomes in the mother, foetus and neonates. We assessed the comparative diagnostic performance of Malaria Rapid Diagnostic Test (mRDT), microscopy and PCR for malaria diagnosis in pregnant women for early detection of asymptomatic malaria in pregnant women. Study design: Five hundred and twenty Pregnant women attending study clinics within Ikene and Remo North LGAs with gestational age between 16 and 29 weeks, willing and consented; were enrolled into the study. Blood samples collected via venepuncture were screened for malaria using microscopy, mRDTs kits, and PCR techniques on their first visit (V1) and at delivery. The parasite positivity rates, sensitivity and specificity were calculated and compared for each technique using PCR as the standard. Data was entered into REDCap® online database and analysis done using Stata and MedCalc®. Results and conclusions: Average age of enrolled women was 28.8 years and mean gestational age was 21.0 weeks. The parasite positivity rates were 4.3%, 8.8% and 25.0% for microscopy, mRDT and PCR at V1 and was 2.4%, 3.4% and 43.4% at delivery, respectively. Sensitivity for microscopy and mRDT was 11.2% and 30.3% respectively at V1, while specificity was 98.2% and 98.5%. At delivery, the sensitivity reduced to 1.6% and 4.9%; while specificity was 96.9% and 97.6% respectively. Only 2.3% cases correlated with all three diagnostic methods. Our data showed a decrease in sensitivity of the diagnostic methods as pregnancy progressed, which may be due to very low parasitaemia, but high specificity. Our study demonstrated a high rate of subpatent parasitaemia amongst pregnant women. This finding therefore raises the question of the effect of subpatent parasitaemia on the health of the mother and foetus.

Elucidating colony bloom formation mechanism of a harmful alga Phaeocystis globosa (Prymnesiophyceae) using metaproteomics.

Phaeocystis is a globally distributed Prymnesiophyte genus and usually forms massive harmful colony blooms, which impact marine ecosystem, mariculture, human health, and even threaten coastal nuclear power plant safety. However, the mechanisms behind the colony formation from the solitary cells remain poorly understood. Here, we investigated metabolic processes of both solitary and non-flagellated colonial cells of Phaeocystis globosa at different colony bloom stages in the subtropical Beibu Gulf using a metaproteomic approach. Temperature was significantly correlated with Phaeocystis colony bloom formation, and the flagellated motile solitary cells with abundant flagellum-associated proteins, such as tubulin and dynein, were the exclusive cellular morphotype at the solitary cell stage featured with temperatures ≥21 °C. When the temperature decreased to <21 °C, tiny colonies appeared and the flagellum-associated proteins were down-regulated in both solitary and non-flagellated colonial cells, while proteins involved in biosynthesis, chain polymerization and aggregation of glycosaminoglycan (GAG), a key constituent of gelatinous matrix, were up-regulated, indicating the central role of active GAG biosynthesis during the colony formation. Furthermore, light utilization, carbon fixation, nitrogen assimilation, and amino acid and protein synthesis were also enhanced to provide sufficient energy and substrates for GAG biosynthesis. This study highlighted that temperature induced re-allocation of energy and substances toward GAG biosynthesis is essential for colony bloom formation of P. globosa.

The impact assessment of desalination plant discharges on heavy metal pollution in the coastal sediments of the Persian Gulf.

In recent decades the development of desalination plants (DPs) for desalination of seawater has increased dramatically, while little attention has been paid to the effects of this activity on the accumulation of heavy metals (HMs) in the sediments of affected ecosystems. The present study was implemented to evaluate (1) heavy metal accumulation in sediments impacted by DPs discharges, (2) spatial and temporal changes of HMs and the contamination degree by different types of pollution indexes (single and integrated indices), and (3) ecological risk assessment of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) in sediments affected by DPs discharges. A total of 288 sediment samples were collected seasonally at 24 stations from November 2019 to October 2020. Analysis of HMs concentrations in sediments near the desalination plant discharge provided evidence of local contamination. Maximum concentration of Cu and Pb elements were found in sediments near the desalination plant discharge point. Hierarchical cluster analysis revealed clear segregation of stations impacted by desalination plant discharges and away from discharges. The values of PLI index in sediments of all sampling stations were < 1, indicating that there was no metal pollution by this index. The potential ecological risk index (PERI) ranged from 5.33 ± 0.51 to 11.81 ± 4.98 in sampling sediments and were classified as "low potential ecological risk". These results demonstrate that the DPs discharge increased HMs concentrations in the sediments in close proximity to outlets. The necessary and practical regulations and policies regarding the rejection of the DPs discharge and disposal of chemical compounds must be implemented and enforced.

Bacterial Composition Associated With Giant Colonies of the Harmful Algal Species Phaeocystis globosa.

The cosmopolitan algae Phaeocystis globosa forms harmful algal blooms frequently in a number of tropical and subtropical coastal regions in the past two decades. During the bloom, the giant colony, which is formed by P. globosa, is the dominant morphotype. However, the microenvironment and the microbial composition in the intracolonial fluid are poorly understood. Here, we used high-throughput 16S rRNA amplicon sequencing to examine the bacterial composition and predicted functions in intracolonial fluid. Compared with the bacterial consortia in ambient seawater, intracolonial fluids possessed the lower levels of microbial richness and diversity, implying selectivity of bacteria by the unique intracolonial microenvironment enclosed within the P. globosa polysaccharide envelope. The bacterial consortia in intracolonial fluid were dominated by Balneola (48.6% of total abundance) and Labrezia (28.5%). The bacteria and microbial function enriched in intracolonial fluid were involved in aromatic benzenoid compounds degradation, DMSP and DMS production and consumption, and antibacterial compounds synthesis. We suggest that the P. globosa colonial envelope allows for the formation of a specific microenvironment; thus, the unique microbial consortia inhabiting intracolonial fluid has close interaction with P. globosa cells, which may benefit colony development.

The Impact of Early Life Exposure to Cannabis: The Role of the Endocannabinoid System.

Cannabis use during pregnancy has continued to rise, particularly in developed countries, as a result of the trend towards legalization and lack of consistent, evidence-based knowledge on the matter. While there is conflicting data regarding whether cannabis use during pregnancy leads to adverse outcomes such as stillbirth, preterm birth, low birthweight, or increased admission to neonatal intensive care units, investigations into long-term effects on the offspring's health are limited. Historically, studies have focused on the neurobehavioral effects of prenatal cannabis exposure on the offspring. The effects of cannabis on other physiological aspects of the developing fetus have received less attention. Importantly, our knowledge about cannabinoid signaling in the placenta is also limited. The endocannabinoid system (ECS) is present at early stages of development and represents a potential target for exogenous cannabinoids in utero. The ECS is expressed in a broad range of tissues and influences a spectrum of cellular functions. The aim of this review is to explore the current evidence surrounding the effects of prenatal exposure to cannabinoids and the role of the ECS in the placenta and the developing fetus.

Seasonal resource pulses and the foraging depth of a Southern Ocean top predator.

Seasonal resource pulses can have enormous impacts on species interactions. In marine ecosystems, air-breathing predators often drive their prey to deeper waters. However, it is unclear how ephemeral resource pulses such as near-surface phytoplankton blooms alter the vertical trade-off between predation avoidance and resource availability in consumers, and how these changes cascade to the diving behaviour of top predators. We integrated data on Weddell seal diving behaviour, diet stable isotopes, feeding success and mass gain to examine shifts in vertical foraging throughout ice break-out and the resulting phytoplankton bloom each year. We also tested hypotheses about the likely location of phytoplankton bloom origination (advected or produced in situ where seals foraged) based on sea ice break-out phenology and advection rates from several locations within 150 km of the seal colony. In early summer, seals foraged at deeper depths resulting in lower feeding rates and mass gain. As sea ice extent decreased throughout the summer, seals foraged at shallower depths and benefited from more efficient energy intake. Changes in diving depth were not due to seasonal shifts in seal diets or horizontal space use and instead may reflect a change in the vertical distribution of prey. Correspondence between the timing of seal shallowing and the resource pulse was variable from year to year and could not be readily explained by our existing understanding of the ocean and ice dynamics. Phytoplankton advection occurred faster than ice break-out, and seal dive shallowing occurred substantially earlier than local break-out. While there remains much to be learned about the marine ecosystem, it appears that an increase in prey abundance and accessibility via shallower distributions during the resource pulse could synchronize life-history phenology across trophic levels in this high-latitude ecosystem.

Alterations of Circulating Biomarkers During Late Term Pregnancy Complications in the Horse Part I: Cytokines.

Equine abortions are attributed to both infectious and noninfectious causes. Clinical extrapolations are often made from the experimental model for ascending placentitis towards other causes of fetal compromise, including various markers of inflammation, including the cytokines IL-2, 5, IL-6, IL-10, IFNγ, and TNF. It is unknown if these cytokine changes are noted under field conditions, or if they increase preceding other pregnancy related complications. To assess this, Thoroughbred mares (n = 702) had weekly blood obtained beginning in December 2013 and continuing until parturition. Fetal membranes were submitted to the UKVDL for complete gross and pathologic assessment and classified as either ascending placentitis (n = 6), focal mucoid placentitis (n = 6), idiopathic abortion (n = 6) or control (n = 20). Weekly serum samples were analyzed via immunoassay for concentrations of IL-2, IL-5, IL-6, IL-10, IFNγ, and TNF. For both focal mucoid placentitis and ascending placentitis, an increase (P < .05) in the concentrations of IL-2, IL-5, IL-6, IL-10, IFNγ, and TNF was noted preceding parturition in comparison to controls. Cytokine profiles preceding idiopathic abortion did not differ from controls. In conclusion, serum cytokines may be considered potential biomarkers for the prediction of placental infection, while no changes in cytokine profiles were noted when noninfectious causes of abortion occurred. Additionally, this is the first study to report an increase in cytokines during the disease process of focal mucoid placentitis, the etiology of which includes Nocardioform placentitis.

Delta-9-tetrahydrocannabinol inhibits invasion of HTR8/SVneo human extravillous trophoblast cells and negatively impacts mitochondrial function.

Prenatal cannabis use is a significant problem and poses important health risks for the developing fetus. The molecular mechanisms underlying these changes are not fully elucidated but are thought to be attributed to delta-9-tetrahydrocannabinol (THC), the main bioactive constituent of cannabis. It has been reported that THC may target the mitochondria in several tissue types, including placental tissue and trophoblast cell lines, and alter their function. In the present study, in response to 48-h THC treatment of the human extravillous trophoblast cell line HTR8/SVneo, we demonstrate that cell proliferation and invasion are significantly reduced. We further demonstrate THC-treatment elevated levels of cellular reactive oxygen species and markers of lipid damage. This was accompanied by evidence of increased mitochondrial fission. We also observed increased expression of cellular stress markers, HSP70 and HSP60, following exposure to THC. These effects were coincident with reduced mitochondrial respiratory function and a decrease in mitochondrial membrane potential. Taken together, our results suggest that THC can induce mitochondrial dysfunction and reduce trophoblast invasion; outcomes that have been previously linked to poor placentation. We also demonstrate that these changes in HTR8/SVneo biology may be variably mediated by cannabinoid receptors CB1 and CB2.

The imbalance of the Th17/Treg axis following equine ascending placental infection.

Ascending placentitis is a leading cause of abortion in the horse, but adaptive immune response to this disease is unknown. To evaluate this, sub-acute placentitis was experimentally-induced via trans-cervical inoculation of S. zooepidemicus, and endometrium and chorioallantois was collected 8 days later (n = 6 inoculated/n = 6 control). The expression of transcripts relating to Th1, Th2, Th17, and Treg maturation was assessed via RNASeq. IHC of transcription factors relating to each subtype in the same tissues (Th1: TBX21, Th2: GATA3, Th17: IRF4, Treg: FOXp3). An immunoassay was utilized to assess circulating cytokines (Th1: IFNg, IL-2; Th2: IL-4, IL-5; Th17: IL-17, IL-6; Treg: IL-10, GM-CSF). An increase in Th1 and Th17-related transcripts were noted in the chorioallantois, although no alterations were seen in the endometrium. Th2 and Treg-related transcripts altered in a dysregulated manner, as some transcripts increased in expression while others decreased. Immunolocalization of Th1, Th2, and Th17 cells was increased in diseased chorioallantois, while no Treg cells were noted in the diseased tissue. Secreted cytokines relating to Th1 (IFNg, IL-2), Th17 (IL-6), Th2 (IL-5), and Treg (IL-10) populations increased in maternal circulation eight days after inoculation. In conclusion, the Th1/Th17 response to ascending placentitis occurs primarily in the chorioallantois, indicating the adaptive immune response to occur in fetal derived placental tissue. Additionally, ascending placentitis leads to an increase in the helper T cell populations (Th1/Th17/Th2) while decreasing the Treg response. This increase in Th17-related responses alongside a diminishing Treg-related response may precede or contribute to fetal demise, abortion, or preterm labor.

Pathways of the family stress model in midlife on physical health in later adulthood.

The current study examined economic adversity and physical health outcomes in line with the family stress model (FSM) for husbands and wives in enduring marriages. Data came from 243 husbands and wives who participated from early middle to later adulthood. Assessments included observational and self-report measures. Economic hardship and economic pressure were assessed in early middle adulthood. Feelings of hostility and observed harsh couple interaction were examined in middle adulthood, and physical impairment was assessed in later adulthood. Results indicated that economic hardship related to economic pressure. In addition, economic pressure indirectly related to physical impairment via hostility and harsh couple interaction. For husbands, economic pressure was also directly associated with their own physical impairment in later adulthood. Finally, economic pressure was indirectly associated with husband to wife harsh couple interaction through wife hostility. Similarly, economic pressure was indirectly associated with wife to husband harsh couple interaction through husband hostility. Results suggest that economic adversity as experienced in early middle adulthood has long-term health consequences into later adulthood. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Delta-9-tetrahydrocannabinol disrupts mitochondrial function and attenuates syncytialization in human placental BeWo cells.

The psychoactive component in cannabis, delta-9-tetrahydrocannabinol, can restrict fetal growth and development. Delta-9-tetrahydrocannabinol has been shown to negatively impact cellular proliferation and target organelles like the mitochondria resulting in reduced cellular respiration. In the placenta, mitochondrial dysfunction leading to oxidative stress prevents proper placental development and function. A key element of placental development is the proliferation and fusion of cytotrophoblasts to form the syncytium that comprises the materno-fetal interface. The impact of delta-9-tetrahydrocannabinol on this process is not well understood. To elucidate the nature of the mitochondrial dysfunction and its consequences on trophoblast fusion, we treated undifferentiated and differentiated BeWo human trophoblast cells, with 20 µM delta-9-tetrahydrocannabinol for 48 hr. At this concentration, delta-9-tetrahydrocannabinol on BeWo cells reduced the expression of markers involved in syncytialization and mitochondrial dynamics, but had no effect on cell viability. Delta-9-tetrahydrocannabinol significantly attenuated the process of syncytialization and induced oxidative stress responses in BeWo cells. Importantly, delta-9-tetrahydrocannabinol also caused a reduction in the secretion of human chorionic gonadotropin and the production of human placental lactogen and insulin growth factor 2, three hormones known to be important in facilitating fetal growth. Furthermore, we also demonstrate that delta-9-tetrahydrocannabinol attenuated mitochondrial respiration, depleted adenosine triphosphate, and reduced mitochondrial membrane potential. These changes were also associated with an increase in cellular reactive oxygen species, and the expression of stress responsive chaperones, HSP60 and HSP70. These findings have important implications for understanding the role of delta-9-tetrahydrocannabinol-induced mitochondrial injury and the role this might play in compromising human pregnancies.

Reactive oxygen species from mitochondria impacts trophoblast fusion and the production of endocrine hormones by syncytiotrophoblasts.

The placenta, a tissue that is metabolically active and rich in mitochondria, forms a critical interface between the mother and developing fetus. Oxidative stress within this tissue, derived from the dysregulation of reactive oxygen species (ROS), has been linked to a number of adverse fetal outcomes. While such outcomes have been associated with mitochondrial dysfunction, the causal role of mitochondrial dysfunction and mitochondrially generated ROS in altering the process of placentation remains unclear. In this study, mitochondrial complex I activity was attenuated using 10 nM rotenone to induce cellular oxidative stress by increasing mitochondrial ROS production in the BeWo choriocarcinoma cell line. Increased mitochondrial ROS resulted in a significant decrease in the transcripts which encode for proteins associated with fusion (GCM1, ERVW-1, and ERVFRD-1) resulting in a 5-fold decrease in the percentage of BeWo fusion. This outcome was associated with increased indicators of mitochondrial fragmentation, as determined by decreased expression of MFN2 and OPA1 along with an increase in a marker of mitochondrial fission (DRP1). Importantly, increased mitochondrial ROS also resulted in a 5.0-fold reduction of human placental lactogen (PL) and a 4.4-fold reduction of insulin like growth factor 2 (IGF2) transcripts; hormones which play an important role in regulating fetal growth. The pre-treatment of rotenone-exposed cells with 5 mM N-acetyl cysteine (NAC) resulted in the prevention of these ROS mediated changes in BeWo function and supports a central role for mitochondrial ROS signaling in the maintenance and function of the materno-fetal interface.

Prevention is better than cure: Persian Gulf biodiversity vulnerability to the impacts of desalination plants.

Due to extremely high rates of evaporation and low precipitation in the Persian Gulf, discharges from desalination plants (DPs) can lead to ecological stresses by increasing water temperatures, salinities, and heavy metal concentrations, as well as decreasing dissolved oxygen levels. We discuss the potential ecological impacts of DPs on marine organisms and propose mitigating measures to reduce the problems induced by DPs discharges. The daily capacity of DPs in the Persian Gulf exceeds 11 million m3 per day, which is approximately half of global daily freshwater production; multistage flash distillation (MSF) is the dominant desalination process. Results from field and laboratory studies indicate that there are potentially serious and chronic threats to marine communities following exposure to DP discharges, especially within the zoobenthos, echinodermata, seagrasses, and coral reefs. DP discharges can lead to decreases in sensitive species, plankton abundance, hard substrate epifauna, and growth rates of seagrasses. However, the broad applicability of any one of these impacts is currently hard to scale because of the limited number of studies that have been conducted to assess the ecological impacts of DP discharge on Persian Gulf organisms. Even so, available data suggest that appropriately sited, designed, and operated DPs combined with current developments in impingement and entrainment reduction technology can mitigate many of the negative environmental impacts of DPs.

The role of the endocannabinoid system in female reproductive tissues.

There has been increasing interest in the role of endocannabinoids as critical modulators of the female reproductive processes. Endocannabinoids are natural ligands of cannabinoid, vanilloid, and peroxisome proliferator-activated receptors. Together with their receptors, enzymes and downstream signaling targets, they form the endocannabinoid system (ECS). While the ECS is known to modulate pain and neurodevelopment, it is also known to impact the female reproductive system where it affects folliculogenesis, oocyte maturation, and ovarian endocrine secretion. In addition, the ECS affects oviductal embryo transport, implantation, uterine decidualization and placentation. There is a complex interplay between the ECS and the hypothalamic-pituitary-ovarian axis, and an intricate crosstalk between the ECS and steroid hormone production and secretion. Exogenous cannabinoids, derived from plants such as Cannabis sativa, are also ligands for cannabinoid receptors. These have been shown to have clinical outcomes related to ECS dysregulation, including multiple sclerosis, Alzheimer's disease, and amyotrophic lateral sclerosis, along with adverse effects on female reproduction. The aim of this review is to describe and discuss data from human, animal, and in vitro studies that support the important role of the endocannabinoid system in female reproductive tissues and processes. In particular, we will discuss some of the mechanisms by which endocannabinoid signaling can affect ovarian function in both physiological and pathophysiological states.

Vasculitis hipocomplementémica urticarial no dolorosa que debuta con astenia severa: informe de caso / Hypocomplementemic urticarial vasculitis not painful due to severe astennia: case report

La vasculitis urticarial es una enfermedad clinicopatológica que se caracteriza por episodios recurrentes de urticaria y vasculitis leucocitoclástica; en este trabajo se presenta la variante síndrome urticarial vasculítico hipocomplementémica, que afecta a los vasos pequeños y está asociado con anticuerpos anti-C1q y caracterizado, principalmente, por lesiones urticariales no pruriginosas de más de 24 horas de evolución preferentemente en mujeres en la cuarta década de la vida). Se presenta una paciente femenina de 33 años de edad que debutó con astenia severa y lesiones dermatológicas de tipo maculopapular de morfología anular no dolorosa, no pruriginosas, en el Hospital Medical Center de Tegucigalpa, Honduras, con un tiempo medio de evolución de la enfermedad de 24 meses. Se enviaron muestras séricas a laboratorios en los Estados Unidos de América para completar estudios inmunológicos y se envió muestra de biopsia de lesión dermatológica al Quest Diagnostics Incorporated Nichols Institute para inmunohistoquímica, que informó vasculitis por complemento bajo con tinción inmunohistoquímica positiva para antígeno anti C1q. El correcto diagnóstico ante un síndrome vasculítico dependerá de la exclusión de causas secundarias mediante el uso adecuado de los diferentes métodos diagnósticos y una alta sospecha clínica que garantice la certeza del abordaje diagnóstico(AU)

Model peptide studies of Ag+ binding sites from the silver resistance protein SilE.

Using model peptides, each of the nine MX2H or HXnM (n = 1, 2) motifs of the silver resistance protein SilE has been shown to coordinate to one Ag+ ion by its histidine and methionine residues with Kd in the µM range. This suggests an Ag+ buffering role for SilE in the case of high Ag+ overload.

Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota.

Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed.

The oceanography and ecology of the Ross Sea.

The continental shelf of the Ross Sea exhibits substantial variations in physical forcing, ice cover, and biological processes on a variety of time and space scales. Its circulation is characterized by advective inputs from the east and exchanges with off-shelf regions via the troughs along the northern portions. Phytoplankton biomass is greater there than anywhere else in the Antarctic, although nitrate is rarely reduced to levels below 10 µmol L(-1). Overall growth is regulated by irradiance (via ice at the surface and by the depths of the mixed layers) and iron concentrations. Apex predators reach exceptional abundances, and the world's largest colonies of Adélie and emperor penguins are found there. Krill are represented by two species (Euphausia superba near the shelf break and Euphausia crystallorophias throughout the continental shelf region). Equally important and poorly known is the Antarctic silverfish (Pleuragramma antarcticum), which is also consumed by most upper-trophic-level predators. Future changes in the Ross Sea environment will have profound and unpredictable effects on the food web.

CHOLERA EPIDEMIOLOGY IN ZAMBIA FROM 2000 TO 2010: IMPLICATIONS FOR IMPROVING CHOLERA PREVENTION AND CONTROL STRATEGIES IN THE COUNTRY.

OBJECTIVE: To review the cholera epidemiology in Zambia from 2000 to 2010 in order to highlight the key lessons learned. Based on our findings, we make recommendations for improving cholera prevention and control in country. DESIGN: Ten years descriptive cholera data was extracted from the national IDSR database and analysed. SETTING: The study was conducted in Zambia using national epidemiology data which were disaggregated by Province. SUBJECTS: None. RESULTS: Starting from 2003, there has been a progressive increase in yearly incidence of cholera in the country. In 2010, 6794 cases (500% increase compared to 2003) and 115 deaths (CFR 1.6%) of the disease were reported with Lusaka Province accounting for 85% of the total cases. Outbreaks start between epidemiological weeks 40 to 45 of the year and ends between weeks 20 to 25 of the following year (which corresponds to the Zambian rainy season). Outbreaks are largely confined to the peri-urban areas of Lusaka, Luapula, Southern and Copperbelt Provinces. CONCLUSION: In the last 10-20 years, the epidemiology of cholera in Zambia has changed; Laboratory confirmation of Vibrio cholerae in the country on a yearly basis in the last ten years suggests that the country is now endemic for cholera hence the need to review current cholera prevention and control strategies.