Giants of the Amazon: How does environmental variation drive the diversity patterns of large trees?

For more than three decades, major efforts in sampling and analyzing tree diversity in South America have focused almost exclusively on trees with stems of at least 10 and 2.5 cm diameter, showing highest species diversity in the wetter western and northern Amazon forests. By contrast, little attention has been paid to patterns and drivers of diversity in the largest canopy and emergent trees, which is surprising given these have dominant ecological functions. Here, we use a machine learning approach to quantify the importance of environmental factors and apply it to generate spatial predictions of the species diversity of all trees (dbh ≥ 10 cm) and for very large trees (dbh ≥ 70 cm) using data from 243 forest plots (108,450 trees and 2832 species) distributed across different forest types and biogeographic regions of the Brazilian Amazon. The diversity of large trees and of all trees was significantly associated with three environmental factors, but in contrasting ways across regions and forest types. Environmental variables associated with disturbances, for example, the lightning flash rate and wind speed, as well as the fraction of photosynthetically active radiation, tend to govern the diversity of large trees. Upland rainforests in the Guiana Shield and Roraima regions had a high diversity of large trees. By contrast, variables associated with resources tend to govern tree diversity in general. Places such as the province of Imeri and the northern portion of the province of Madeira stand out for their high diversity of species in general. Climatic and topographic stability and functional adaptation mechanisms promote ideal conditions for species diversity. Finally, we mapped general patterns of tree species diversity in the Brazilian Amazon, which differ substantially depending on size class.

Numerical and experimental study on mechanical behaviour of the AlSi10Mg aluminium structures manufactured additively and subjected to a blast wave

The paper is related to energy absorptive properties of additively manufactured metallic cellular structures. The samples of Honeycomb, Auxetic, rhomboidal Lattice and a regular Foam are subjected to a dynamic compression due to the blast tests. The cuboidal samples are manufactured by the Direct Metal Laser Sintering (DMLS) method using AlSi10Mg aluminium powder. The experimental tests are performed by means of an Explosive Driven Shock Tube (EDST). The measured results of the transmitted forces in relation to the shortening of the samples allow to analyse the deformation processes of each selected geometry. In addition, the evaluation of the structural responses leads to identification of the structure properties, such as the equivalent stress over equivalent strain or the energy absorption per a unit of mass. Moreover, the process of compression is modelled numerically using the explicit code LS-DYNA R9.0.1. The obtained simulations provide the complete analysis of the experimentally observed mechanisms.

Tree mode of death and mortality risk factors across Amazon forests

The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted-modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth-survival trade-off in driving tropical tree mortality.

The Forest Observation System, building a global reference dataset for remote sensing of forest biomass

Forest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (AGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. AGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world's forests. All plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS-based biomass products while developing new synergies between the RS and ground-based ecosystem research communities.

Analysis of radioprotection and antimutagenic effects of Ilex paraguariensis infusion and its component rutin

DNA repair pathways, cell cycle checkpoints, and redox protection systems are essential factors for securing genomic stability. The aim of the present study was to analyze the effect of Ilex paraguariensis (Ip) infusion and one of its polyphenolic components rutin on cellular and molecular damage induced by ionizing radiation. Ip is a beverage drank by most inhabitants of Argentina, Paraguay, Southern Brazil, and Uruguay. The yeast Saccharomyces cerevisiae (SC7Klys 2-3) was used as the eukaryotic model. Exponentially growing cells were exposed to gamma rays (γ) in the presence or absence of Ip or rutin. The concentrations used simulated those found in the habitual infusion. Surviving fractions, mutation frequency, and DNA double-strand breaks (DSB) were determined after treatments. A significant increase in surviving fractions after gamma irradiation was observed following combined exposure to γ+R, or γ+Ip. Upon these concomitant treatments, mutation and DSB frequency decreased significantly. In the mutant strain deficient in MEC1, a significant increase in γ sensitivity and a low effect of rutin on γ-induced chromosomal fragmentation was observed. Results were interpreted in the framework of a model of interaction between radiation-induced free radicals, DNA repair pathways, and checkpoint controls, where the DNA damage that induced activation of MEC1 nodal point of the network could be modulated by Ip components including rutin. Furthermore, ionizing radiation-induced redox cascades can be interrupted by rutin potential and other protectors contained in Ip.

Continuous soil carbon storage of old permanent pastures in Amazonia

Amazonian forests continuously accumulate carbon (C) in biomass and in soil, representing a carbon sink of 0.42-0.65 GtC yr^-1 . In recent decades, more than 15% of Amazonian forests have been converted into pastures, resulting in net C emissions (~200 tC ha^-1 ) due to biomass burning and litter mineralization in the first years after deforestation. However, little is known about the capacity of tropical pastures to restore a C sink. Our study shows in French Amazonia that the C storage observed in native forest can be partly restored in old (≥24 year) tropical pastures managed with a low stocking rate (±1 LSU ha^-1 ) and without the use of fire since their establishment. A unique combination of a large chronosequence study and eddy covariance measurements showed that pastures stored between -1.27 ± 0.37 and -5.31 ± 2.08 tC ha^-1  yr^-1 while the nearby native forest stored -3.31 ± 0.44 tC ha^-1  yr^-1 . This carbon is mainly sequestered in the humus of deep soil layers (20-100 cm), whereas no C storage was observed in the 0- to 20-cm layer. C storage in C4 tropical pasture is associated with the installation and development of C3 species, which increase either the input of N to the ecosystem or the C:N ratio of soil organic matter. Efforts to curb deforestation remain an obvious priority to preserve forest C stocks and biodiversity. However, our results show that if sustainable management is applied in tropical pastures coming from deforestation (avoiding fires and overgrazing, using a grazing rotation plan and a mixture of C3 and C4 species), they can ensure a continuous C storage, thereby adding to the current C sink of Amazonian forests.

Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils

Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground biomass), and dynamics (growth, mortality, aboveground wood productivity) of nutrient-poor tropical forests. Most variables did not covary with site-level changes in soil nutrient content, indicating that nutrient-cycling mechanisms other than the direct absorption from soil (e.g. the nutrient uptake from litter, the resorption, or the storage of nutrients in the biomass), may strongly control forest structure and dynamics. Ecosystem-level adaptations to low soil nutrient availability and long-term low levels of disturbance may help to account for the lower productivity and higher accumulation of biomass in nutrient-poor forests compared to nutrient-richer forests.

HMGB1 mediates splenomegaly and expansion of splenic CD11b+ Ly-6C(high) inflammatory monocytes in murine sepsis survivors

BACKGROUND

More than 500,000 hospitalized patients survive severe sepsis annually in the USA. Recent epidemiological evidence, however, demonstrated that these survivors have significant morbidity and mortality, with 3-year fatality rates higher than 70%. To investigate the mechanisms underlying persistent functional impairment in sepsis survivors, here we developed a model to study severe sepsis survivors following cecal ligation and puncture (CLP).

METHODS

Sepsis was induced in mice by CLP and survivors were followed for twelve weeks. Spleen and blood were collected and analyzed at different time points post-sepsis.

RESULTS

We observed that sepsis survivors developed significant splenomegaly. Analysis of the splenic cellular compartments revealed a major expansion of the inflammatory CD11b+ Ly-6CHigh pool. Serum high-mobility group box 1 (HMGB1) levels in the sepsis surviving mice were significantly elevated for 4-6 weeks after post-sepsis, and administration of an anti-HMGB1 monoclonal antibody significantly attenuated splenomegaly as well as splenocyte priming. Administration of recombinant HMGB1 to naive mice induced similar splenomegaly, leukocytosis and splenocyte priming as observed in sepsis survivors. Interestingly analysis of circulating HMGB1 from sepsis survivors by mass spectroscopy demonstrated a stepwise increase of reduced form of HMGB1 (with known chemo-attractant properties) during the first 3 weeks, followed by disulphide form (with known inflammatory properties) 4-8 weeks after CLP.

DISCUSSION

Our results indicate that prolonged elevation of HMGB1 is a necessary and sufficient mediator of splenomegaly and splenocyte expansion, as well as splenocyte inflammatory priming in murine severe sepsis survivors.

Nouvelles connaissances sur la dynamique globale de la biomasse après exploitation en forêt nord amazonienne

L'article présente les effets de l'exploitation forestière sur la dynamique de la biomasse aérienne à partir des résultats issus de l'exploitation commerciale au sein de deux forêts : Cikel dans l'Est du Pará au Brésil et Paracou en Guyane française. L'objectif principal a été de comparer l'impact de ce type d'exploitation sur la régénération de la biomasse aérienne dans ces deux forêts dont les caractéristiques sont différentes en termes de structure et de croissance. Dans les deux sites, l'intensité de l'exploitation s'avère être un facteur essentiel déterminant de la perte de biomasse et le temps nécessaire à sa régénération. À Paracou, la régénération de la biomasse aérienne perdue lors des coupes d'abattage de 10 arbres par hectare prendra 45 ans et plus de 100 ans en cas d'exploitation à plus forte intensité (21 arbres par hectare). À la Cikel, la biomasse aérienne se régénérera au bout de 49 ans après exploitation à raison de 6 arbres par hectare et au bout de 87 ans après prélèvement de 8 arbres par hectare. Cette régénération prendra donc autant de temps sur les deux sites, mais avec un moindre nombre d'arbres exploités à la Cikel, les arbres abattus étant de plus grande taille avec une biomasse aérienne individuelle plus importante qu'à Paracou. Après le passage en coupe, l'étude a établi une corrélation directe de la dynamique de la biomasse aérienne avec la structure initiale de la forêt ainsi qu'avec les paramètres de la dynamique forestière : mortalité, croissance et recrutement. L'accumulation de biomasse aérienne par la croissance globale des peuplements après coupe s'avère être un paramètre clé pour le stockage net du carbone, toutefois la contribution du recrutement ne devient significative à Paracou qu'au bout de 10 ans après exploitation. Il s'agit donc de favoriser la croissance des arbres résiduels après la coupe, grâce aux traitements sylvicoles tels que l'éclaircie sélective ou l'élimination de lianes. Alors que les deux forêts sont géographiquement assez proches, leurs capacités de régénération ne sont pas identiques et, en raison de la différence significative de taille des arbres, la forêt guyanaise pourrait tolérer une plus forte intensité d'exploitation.

WHO guidelines for the programmatic management of drug-resistant tuberculosis: 2011 update

The production of guidelines for the management of drug-resistant tuberculosis (TB) fits the mandate of the World Health Organization (WHO) to support countries in the reinforcement of patient care. WHO commissioned external reviews to summarise evidence on priority questions regarding case-finding, treatment regimens for multidrug-resistant TB (MDR-TB), monitoring the response to MDR-TB treatment, and models of care. A multidisciplinary expert panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to develop recommendations. The recommendations support the wider use of rapid drug susceptibility testing for isoniazid and rifampicin or rifampicin alone using molecular techniques. Monitoring by sputum culture is important for early detection of failure during treatment. Regimens lasting ≥ 20 months and containing pyrazinamide, a fluoroquinolone, a second-line injectable drug, ethionamide (or prothionamide), and either cycloserine or p-aminosalicylic acid are recommended. The guidelines promote the early use of antiretroviral agents for TB patients with HIV on second-line drug regimens. Systems that primarily employ ambulatory models of care are recommended over others based mainly on hospitalisation. Scientific and medical associations should promote the recommendations among practitioners and public health decision makers involved in MDR-TB care. Controlled trials are needed to improve the quality of existing evidence, particularly on the optimal composition and duration of MDR-TB treatment regimens.

Drought-mortality relationships for tropical forests

*The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. *We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. *In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. *These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

Modeling decay rates of dead wood in a neotropical forest

Variation of dead wood decay rates among tropical trees remains one source of uncertainty in global models of the carbon cycle. Taking advantage of a broad forest plot network surveyed for tree mortality over a 23-year period, we measured the remaining fraction of boles from 367 dead trees from 26 neotropical species widely varying in wood density (0.23-1.24 g cm(-3)) and tree circumference at death time (31.5-272.0 cm). We modeled decay rates within a Bayesian framework assuming a first order differential equation to model the decomposition process and tested for the effects of forest management (selective logging vs. unexploited), of mode of death (standing vs. downed) and of topographical levels (bottomlands vs. hillsides vs. hilltops) on wood decay rates. The general decay model predicts the observed remaining fraction of dead wood (R2 = 60%) with only two biological predictors: tree circumference at death time and wood specific density. Neither selective logging nor local topography had a differential effect on wood decay rates. Including the mode of death into the model revealed that standing dead trees decomposed faster than downed dead trees, but the gain of model accuracy remains rather marginal. Overall, these results suggest that the release of carbon from tropical dead trees to the atmosphere can be simply estimated using tree circumference at death time and wood density.

Dynamics of aboveground carbon stocks in a selectively logged tropical forest

The expansion of selective logging in tropical forests may be an important source of global carbon emissions. However, the effects of logging practices on the carbon cycle have never been quantified over long periods of time. We followed the fate of more than 60 000 tropical trees over 23 years to assess changes in aboveground carbon stocks in 48 1.56-ha plots in French Guiana that represent a gradient of timber harvest intensities, with and without intensive timber stand improvement (TSI) treatments to stimulate timber tree growth. Conventional selective logging led to emissions equivalent to more than a third of aboveground carbon stocks in plots without TSI (85 Mg C/ha), while plots with TSI lost more than one-half of aboveground carbon stocks (142 Mg C/ha). Within 20 years of logging, plots without TSI sequestered aboveground carbon equivalent to more than 80% of aboveground carbon lost to logging (-70.7 Mg C/ha), and our simulations predicted an equilibrium aboveground carbon balance within 45 years of logging. In contrast, plots with intensive TSI are predicted to require more than 100 years to sequester aboveground carbon lost to emissions. These results indicate that in some tropical forests aboveground carbon storage can be recovered within half a century after conventional logging at moderate harvest intensities.

Results of the feasibility test of the Practical Approach to Lung Health in the Syrian Arab Republic

We assessed implementation of the Practical Approach to Lung Health (PAL) in primary care facilities in the Syrian Arab Republic and its short-term impact on respiratory care in patients aged 5+ years. After training on PAL for 76 general practitioners in 75 health centres, referrals and sputum smear examinations for patients increased. The mean number of drugs prescribed per patient decreased by 14.8% and that of antibiotics by 33.3%, while prescriptions for inhaled medications increased. The mean cost of drug prescriptions fell by 26.2%.

TB contact investigations: 12 years of experience in the National TB Programme, Morocco 1993-2004

We reviewed data collected from 1993 to 2004 as part of the routine activities of the national tuberculosis (TB) control programme (NTP) in Morocco. More than 1 million household TB contacts were identified in approximately 200,000 investigations. On average, 77% of identified contacts were screened every year; overall prevalence was 2.5%. The proportion of TB cases identified in household contacts of registered cases was 5.6%. This was significantly higher in children under 10 years and in patients registered and diagnosed with symptomatic primary complex. Performing TB contact investigations as part of the routine activities of NTP services is feasible in low-middle-income countries.

Feasibility test results of the Practical Approach to Lung Health in Bishkek, Kyrgyzstan

SETTING

Ambulatory health centres in Bishkek, Kyrgyzstan.

OBJECTIVE

To assess the results of training family doctors in Practical Approach to Lung Health (PAL) techniques.

DESIGN

Comparison of the results of two surveys, before (baseline) and after (impact) training on PAL guidelines. Both surveys were carried out according to the same protocol.

RESULTS

A total of 86 family physicians working in three ambulatory health centres participated in both surveys. Respectively 893 and 992 respiratory patients were registered in the baseline and impact surveys. Baseline survey patients had longer duration of symptoms, were older and had more concomitant health conditions than impact survey patients. Findings suggest that PAL training has resulted in a decrease by one third in referrals to hospital or specialists or for diagnostic tests. Data do not show any improvement in tuberculosis case detection. However, in the impact survey, the number of drugs prescribed per patient decreased by 13.6% and the average cost of prescription of any drug per patient was reduced by 32.2%.

CONCLUSION

The study suggests that training in standardised PAL guidelines is likely to reduce referral as well as drug prescription costs for respiratory patients. These findings need to be confirmed by further studies.

Drought sensitivity of the Amazon rainforest

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.

Training on the Practical Approach to Lung Health: effect on drug prescribing in PHC settings in Jordan

This study assessed whether training physicians on the Practical Approach to Lung Health (PAL) reduces drug prescribing and the cost of drugs prescribed to respiratory patients in the primary health care setting. Data were compared before and after training general practitioners on standard guidelines for case management of respiratory conditions in primary care. A total of 56 general practitioners practising in 25 health centres in 3 out of 12 governorates of Jordan participated in both the baseline survey (n = 6260 respiratory patients) and the impact survey (n = 2709 patients). Training in PAL decreased by 12.2% the number of drugs prescribed per patient, increased the prescription of inhaled medications and reduced the mean cost of a drug prescription per patient by 8.7%.

Seasonal water stress tolerance and habitat associations within four neotropical tree genera

We investigated the relationship between habitat association and physiological performance in four congeneric species pairs exhibiting contrasting distributions between seasonally flooded and terra firme habitats in lowland tropical rain forests of French Guiana, including Virola and Iryanthera (Myristicaceae), Symphonia (Clusiaceae), and Eperua (Caesalpiniaceae). We analyzed 10-year data sets of mapped and measured saplings (stems >150 cm in height and <10 cm diameter at breast height [dbh]) and trees (stems > or =10 cm dbh) across 37.5 ha of permanent plots covering a 300-ha zone, within which seasonally flooded areas (where the water table never descends below 1 m) have been mapped. Additionally, we tested the response of growth, survival, and leaf functional traits of these species to drought and flood stress in a controlled experiment. We tested for habitat preference using a modification of the torus translation method. Strong contrasting associations of the species pairs of Iryanthera, Virola, and Symphonia were observed at the sapling stage, and these associations strengthened for the tree stage. Neither species of Eperua was significantly associated with flooded habitats at the sapling stage, but E. falcata was significantly and positively associated with flooded forests at the tree stage, and trees of E. grandiflora were found almost exclusively in nonflooded habitats. Differential performance provided limited explanatory support for the observed habitat associations, with only congeners of Iryanthera exhibiting divergent sapling survival and tree growth. Seedlings of species associated with flooded forest tended to have higher photosynthetic capacity than their congeners at field capacity. In addition, they tended to have the largest reductions in leaf gas exchange and growth rate in response to experimental drought stress and the least reductions in response to experimental inundation. The corroboration of habitat association with differences in functional traits and, to a lesser extent, measures of performance provides an explanation for the regional coexistence of these species pairs. We suggest that specialization to seasonally flooded habitats may explain patterns of adaptive radiation in many tropical tree genera and thereby provide a substantial contribution to regional tree diversity.

Improving the quality of cohort analysis by incorporating treatment outcomes of 'transferred in' TB cases

Treatment outcomes of patients with tuberculosis (TB) who move between TB units ('transferred out') are often not incorporated in the annual cohort analysis. Experience from Morocco shows that using a simple method, the outcomes of these patients, notified as 'transferred in' cases, can be easily taken into account when compiling the annual report on treatment outcomes. With this method the treatment success rate increased in Morocco by a median of 5.8% (range 5.0-6.7), indicating that the country reached the global target of curing at least 85% of the new smear-positive TB cases detected during the period 1995-2003.

Human resources for control of tuberculosis and HIV-associated tuberculosis

The global targets for tuberculosis (TB) control were postponed from 2000 to 2005, but on current evidence a further postponement may be necessary. Of the constraints preventing these targets being met, the primary one appears to be the lack of adequately trained and qualified staff. This paper outlines: 1) the human resources and skills for global TB and human immunodeficiency virus (HIV) TB control, including the human resources for implementing the DOTS strategy, the additional human resources for implementing joint HIV-TB control strategies and what is known about human resource gaps at global level; 2) the attempts to quantify human resource gaps by focusing on a small country in sub-Saharan Africa, Malawi; and 3) the main constraints to human resources and their possible solutions, under six main headings: human resource planning; production of human resources; distribution of the work-force; motivation and staff retention; quality of existing staff; and the effect of HIV/AIDS. We recommend an urgent shift in thinking about the human resource paradigm, and exhort international policy makers and the donor community to make a concerted effort to bridge the current gaps by investing for real change.

Spatial and temporal co-structure analyses between ichthyofauna and environment: an example in the tropics

Ichthyofauna distribution and habitat characteristics of Thalassia beds in the Grand Cul-de-Sac marin lagoon in Guadeloupe were studied during a one-year survey. Environmental variables (9) were measured monthly in ten sites along with collection of fish communities. The environmental data set, analysed alone through between-within group 'principal component analysis' (PCA), exhibited a significant spatial and temporal variability. The fish data set, however, presented only a significant spatial structure, stable over the year. Given the lack of temporal variability in fish distribution, a 'between-site co-structure analysis' (BSCA) was used to compare the faunistic and environmental structures in space. The co-inertia structure was reduced to one axis representing a strong coast-reef gradient, the major common phenomena to both data sets. Environment and fish distribution allowed to distinguish sites directly under mangrove influence (characterised by high seagrasses, high concentration of chlorophyll a and high densities of zooplankton), to sites under reef influence (with short but dense seagrasses, clear water, and poor nutriments). For that purposes, the BSCA summarised efficiently what in common the fauna spatial structure and the environment spatial structure may present.

Leprosy chemoprophylaxis in Micronesia

A programme of chemoprophylaxis was introduced as a component of the leprosy control programme in the Federated States of Micronesia (FSM), beginning in 1996. The entire population of the country was to be screened, and a single dose of 600 mg rifampicin, 400 mg ofloxacin and 100 mg minocycline (ROM) was to be administered to the entire population. Two rounds of screening the entire population were carried out, approximately 1 year apart, and chemoprophylaxis was administered at the time of each screening. Ninety percent of the population were screened at least once, and 55% were screened in both rounds; 87% of the population received at least one dose, and 54% received two doses. In the course of the first round, 322 new cases were detected, whereas only 80 new cases were detected during the second round, of whom only 12 had received chemoprophylaxis in the course of the first round. A third round of screening, confined to a small number of villages in both Chuuk and Pohnpei, in which states leprosy endemicity was high, was carried out approximately 2 years after the second. Only 16 new cases were detected during the third round of screening, whereas 102 new cases had been detected in this same population during the first round of screening, and 32 new cases during the second. Six of the 16 newly detected cases stated that they had been administered chemoprophylaxis at least once; however, this information may not be reliable.

DOTS in Cambodia. Directly observed treatment with short-course chemotherapy

SETTING

Since the 1970s, Cambodia, a country of 10 million people in South East Asia, has experienced war, genocide and the virtual dismantling of the health system. It has a severe tuberculosis (TB) problem, with a new tuberculosis case notification rate, all forms, of about 150 per 100000 population and a tuberculosis programme, established in the early 1980s, achieving cure rates of only 40-50% in the last decade.

OBJECTIVE

To describe the implementation of a DOTS programme (directly observed treatment with short-course chemotherapy) under difficult conditions and its rapid success on a nation-wide scale.

DESIGN

The World Health Organisation's recommended strategy was implemented in a phased manner throughout the country from 1994. The resources for TB drugs and running costs came from 13 sources. The DOTS strategy was gradually introduced after training and with regular supervision into 120 TB units inside general public hospitals at provincial and district level, after a mapping exercise; 75% of tuberculosis cases, all forms, are hospitalized during the entire initial phase and 85% of the total number of tuberculosis cases received free food from the World Food Programme.

RESULTS

Two and a half years after the start of the new programme, DOTS was implemented in 85% of all public hospitals. In 1996, case-detection rates had reached 127 smear-positive PTB (pulmonary tuberculosis) and 149 PTB all forms per 100000 inhabitants; 90% of all tuberculosis patients received DOTS. From January 1994 to June 1995, 4164 new cases started category 1 treatment (2ERHZ/6EH). Of these, 89% were cured or completed treatment, 5% defaulted, 3% died, 1% were treatment failures and 2% transferred out.

CONCLUSION

The DOTS strategy can be successfully implemented in even very difficult conditions such as those found in Cambodia.

Relapses after a single dose of rifampin in skin-smear negative multibacillary patients after dapsone monotherapy

Between 1982 and 1985, a single 1500 mg dose of rifampin (RMP) was given to 136 multibacillary leprosy patients who had become clinically inactive and skin-smear negative after various durations of dapsone monotherapy, and then antileprosy chemotherapy was totally stopped. By the end of June 1992, 15 relapses were detected among these patients. The overall relapse rate was 11%; the relapse rate per 100 patient-years was 2.1%, which was the highest among those published to date; the cumulative risk of relapse at year 7 of follow up was 8.8%. All of these figures indicate that the relapse rate among this group was at least the same as in other studies where patients received dapsone monotherapy only. Therefore, the administration of a single large dose of RMP could neither prevent relapse nor reduce its rate among multibacillary patients who had already become clinically and skin-smear negative after dapsone monotherapy.