IntroductionThermal stress experiments on corals from habitats with contrasting environmental regimes in understudied regions, such as South Africa, are essential to elucidate the mechanisms underlying coral resilience/susceptibility to thermal stress. This study examined the thermal resilience/susceptibility of Anomastraea irregularis (massive morphology) and Pocillopora verrucosa (branching morphology) collected from environmentally variable intertidal and more stable subtidal habitats from the east coast of South Africa.MethodsCorals were maintained in closed recirculating aquaria and exposed to two thermal stress conditions (28°C and 30°C) for three months, followed by recovery at control conditions (26°C) for two months. Rates of respiration, photosynthesis, and growth were measured monthly. The Symbiodiniaceae density, chlorophyll-a concentration, and lipid concentration were analysed at the start and end of the thermal stress and at the end of the recovery period.ResultsThe treatments induced bleaching in both species from both habitats with an associated decrease in photosynthetic and growth rates. Inherent differences across all measured physiological parameters, including variation in survival, were observed between the species and habitat throughout the experiment, highlighting that environmental origin and possibly morphology can influence thermal tolerance. The intertidal corals were more tolerant than their subtidal conspecifics, and A. irregularis appeared more tolerant than P. verrucosa in both treatments. The intertidal corals decreased their respiration rates to control levels by the end of thermal stress and, both initially and throughout the study, maintained higher Symbiodiniaceae densities, chlorophyll-a, and lipid concentrations than their subtidal conspecifics.DiscussionThe tolerance of A. irregularis may stem from thicker tissue which allowed higher Symbiodiniaceae density and lipid concentrations and lower P:R ratios consistent with a more heterotrophic nature. The photosynthetic and growth rates, Symbiodiniaceae density, chlorophyll-a concentration, and lipid concentration of both species from both habitats did not recover two months after thermal stress indicating that restoration of physiological homeostasis following prolonged thermal stress likely requires substantially longer periods. Therefore, the results in this study should be interpreted as evidence of differential tolerance and early recovery responses rather than complete resilience. These findings provide insight into the physiological mechanisms underpinning thermal tolerance in high-latitude corals, highlighting that corals persisting in environmentally variable environments can exhibit traits critical for understanding resilience to climate change. An important caveat to consider, despite regular water changes, the closed recirculating systems may accumulate metabolic waste products over time, which can independently affect coral physiology and confound thermal stress responses.

During live export, abalone are transported in air, exposing them to environmental hypoxia for extended periods. Hypoxia-inducible factor-1 (HIF-1), a fundamental moderator of hypoxia, activates a variety of genes in response to hypoxic stress, including inducible nitric oxide synthase (iNOS), which is involved in vasodilation, which ultimately can lead to improved perfusion. This study hypothesized that Haliotis midae, the South African abalone, recruits the under-perfused left gill during hypoxia via HIF-1 and iNOS induction whereas changing metabolic rates, transitions to anaerobic respiration and maintaining circulating oxygen by means of reverse Bohr shift that contribute to alleviating tissue hypoxia during 24-h air exposure. Haliotis midae were exposed to air for 24 h as a proxy for hypoxia and were reimmersed in water for 1 h for recovery before the HIF-1 alpha protein expression, iNOS gene expression and 14C inulin space were measured in the gills. We also measured oxygen consumption rates, hemolymph d-lactate levels, pH, and Po2. We found no evidence of HIF-mediated iNOS induction, but abalone hypometabolism and the presence of lactic acid in circulation during the short recovery indicate some reliance on anaerobiosis.

Non-invasive techniques for measuring the physiological performance of corals in situ are important for understanding responses to changing environmental conditions. Two such methods are the 'flexi-chamber' and three-dimensional (3D) photogrammetry. While these have been verified for coral colonies, they have not been tested on coral fragments which are commonly used in field experiments. This study aimed to determine if these methods can effectively measure respiration, photosynthesis, and growth of fragments of massive and sub-massive coral species in the intertidal and subtidal habitats in Park Rynie, South Africa (30.3167 degrees S, 30.7333 degrees E). Differences in respiration and photosynthesis rates between species and habitat were successfully measured using the flexi-chambers. The coral fragments did not show any visual signs of stress (excess mucus production or loss of pigmentation) during the 3-h incubations or an hour after the incubations. 3D models were successfully constructed for all fragments. This study showed that flexi-chambers and 3D photogrammetry can be effectively used to measure the respiration, photosynthesis, and growth of individual coral fragments (3 cm > 4 cm) of different morphology and habitats. The combination of the two methods permits measures of fundamental physiological processes to be attained at relatively low cost and low complexity. This will facilitate studies of a wide range of coral species in situ generating more knowledge on responses to environmental variability.

With increasing urbanization, particularly in developing countries, it is important to understand how local biota will respond to such landscape changes. Bats comprise one of the most diverse groups of mammals in urban areas, and many species are threatened by habitat destruction and land use change. Yet, in Africa, the response of bats to urban areas is relatively understudied. Therefore, we collated data on urban presence, phylogenetic relationship, and ecological traits of 54 insectivorous bats in Africa from available literature to test if their response to urbanization was phylogenetically and/or ecologically driven. Ancestral state reconstruction of urban tolerance, defined by functional group and presence observed in urban areas, suggests that ancestral African bat species could adapt to urban landscapes, and significant phylogenetic signal for urban tolerance indicates that this ability is evolutionarily conserved and mediated by pre-adaptations. Specifically, traits of high wing loading and aspect ratio, and flexible roosting strategies, enable occupancy of urban areas. Therefore, our results identify the traits that predict which bat species will likely occur in urban areas, and which vulnerable bat clades conservation efforts should focus on to reduce loss of both functional and phylogenetic diversity in Africa. We, additionally, highlight several gaps in research that should be investigated in future studies to provide better monitoring of the impact urbanization will have on African bats.

The uMgeni River is one of the most polluted freshwater ecosystems in KwaZulu-Natal. The study aims to assess the response of Clarias gariepinus to water contamination at the Nagle and Inanda dams using selected biomarkers. Samples were collected and preserved as per the analyses to be carried out. Generally, Nagle Dam showed good quality water compared to Inanda Dam. The Inanda Dam population showed a relatively higher prevalence of alterations in the gills and liver than that from Nagle Dam. The degree of alterations showed some variability within each population, however, there was no significant difference (p>0.05) between the two populations. Organ indices of 20 denoting moderate alterations were observed for both populations. Although the mean AChE activity and VtG induction showed no significant difference between the two populations (p>0.05); the lowest AChE activity and the highest VtG level, were observed in the Inanda Dam populations. Both histopathologic and biochemical biomarkers show signs of severely compromised fish health in the Inanda Dam compared to those from Nagle Dam. It is thus, evident that the tributaries feeding the uMgeni River downstream of Nagle Dam are resulting in the increase of pollution level in the Inanda Dam.

Small endotherms commonly use daily torpor to maintain energetic homeostasis. During daily torpor, rewarming rates have a large impact on overall energy savings because they influence heat loss in this energetically costly phase of torpor. These rates are affected by both intrinsic and extrinsic ecological factors; however, data on rewarming rates along temporal and spatial scales between and within species are scant. We investigated how seven insectivorous bat species differing in body size and thermal stability of preferred roosts vary in rewarming rates along an altitude gradient (0-1400 m.a.s.l.) in South Africa, predicting that rewarming rates would increase with altitude. We kept individuals overnight at 15 degrees C and monitored their surface temperature during induced rewarming with infrared thermal imaging to calculate rewarming rates. In contrast to our prediction, we found no significant variation between species or altitudes despite differences in body mass and life history traits. However, we did find evidence that males rewarmed more rapidly than females at low temperatures despite the higher energetic cost of slow rewarming, possibly due to reluctance of females to initiate active rewarming at low ambient temperatures. We found some support for the prediction that cool temperatures at high altitude result lower initial surface temperatures during cold-exposure, as an adaptation to mitigate heat loss through thermal conductance to the ambient environment. This is particularly important for small insectivorous bats given their high surface area to volume ratios.

New insecticidal genes and approaches for pest control are a hot research area. In the present study, we explored a novel strategy for the generation of insecticidal proteins. The midgut cadherin of Helicoverpa armigera (H. armigera) was used as a target to screen materials that have insecticidal activity. After three rounds of panning, the phage-displayed human domain antibody B1F6, which not only binds to the H. armigera cadherin CR9-CR11 but also significantly inhibits Cry1Ac toxins from binding to CR9-CR11, was obtained from a phage-displayed human domain antibody (DAb) library. To better analyze the relevant activity of B1F6, soluble B1F6 protein was expressed by Escherichia coli BL21 (DE3). The cytotoxicity assays demonstrated that soluble B1F6 induced Sf9 cell death when expressing H. armigera cadherin on the cell membrane. The insect bioassay results showed that soluble B1F6 protein (90 μg/cm2) caused 49.5 ± 3.3% H. armigera larvae mortality. The midgut histological results showed that soluble B1F6 caused damage to the midgut epithelium of H. armigera larvae. The present study explored a new strategy and provided a basic material for the generation of new insecticidal materials.

Mammals, born with a near-sterile intestinal tract, are inoculated with their mothers’ microbiome during birth. Thereafter, extrinsic and intrinsic factors shape their intestinal microbe assemblage. Wastewater treatment works (WWTW), sites synonymous with pollutants and pathogens, receive influent from domestic, agricultural and industrial sources. The high nutrient content of wastewater supports abundant populations of chironomid midges (Diptera), which transfer these toxicants and potential pathogens to their predators, such as the banana bat Neoromicia nana (Vespertilionidae), thereby influencing their intestinal microbial assemblages. We used next generation sequencing and 16S rRNA gene profiling to identify and compare intestinal bacteria of N. nana at two reference sites and two WWTW sites. We describe the shared intestinal microbiome of the insectivorous bat, N. nana, consisting of seven phyla and eleven classes. Further, multivariate analyses revealed that location was the most significant driver (sex, body size and condition were not significant) of intestinal microbiome diversity. Bats at WWTW sites exhibited greater intestinal microbiota diversity than those at reference sites, likely due to wastewater exposure, stress and/or altered diet. Changes in their intestinal microbiota assemblages may allow these bats to cope with concomitant stressors.

Small cell lung cancer (SCLC) is a highly aggressive, predominantly cigarette smoke-induced tumour with poor prognosis. The glucocorticoid receptor (GR), a SCLC tumour suppressor gene, is typically reduced in SCLC. We now show that SCLC cells express high levels of DNA methyltransferase 1 (DNMT1) which accumulates at the GR promoter. DNMT1 expression is further increased by exposure to the tobacco carcinogen NNK. In the untransformed human lung fibroblast cell line, MRC-5, short term NNK treatment decreases GRα mRNA and protein expression due to accumulation of DNMT1 at the GR promoter. Long term NNK treatment results in persistently augmented DNMT1 levels with lowered GR levels. Long term exposure to NNK slows cell proliferation and induces DNA damage, while the GR antagonist RU486 stimulates proliferation and protects against DNA damage. Although both NNK and RU486 treatment increases methylation at the GR promoter, neither are sufficient to prevent senescence in this context. NNK exposure results in accumulation of DNMT1 at the GR promoter in untransformed lung cells mimicking SCLC cells, directly linking tobacco smoke exposure to silencing of the GR, an important step in SCLC carcinogenesis.

Increasing rates of urbanisation cause ubiquitous infrastructures that remove anthropogenic contaminants - particularly Wastewater Treatment Works (WWTWs) - to become stressed, and hence pollute surrounding water systems. Neoromicia nana bats are suitable models to study the effects of pollution in these environments because they exploit abundant pollutant-tolerant chironomid midges that breed at WWTWs, and consequently accumulate metals such as iron, copper and zinc in their livers and kidneys. If these metals persist in their circulatory systems, and cross the blood brain barrier (BBB) they can have adverse effects on critical functions such as flight and echolocation. The aim of this study was to investigate the potential neurological effects on N. nana foraging at WWTWs versus bats at reference sites in Durban, South Africa. Our objectives were to 1) compare trace metal levels in brain and hair samples (as a proxy for circulating metals) between N. nana foraging at WWTWs and reference sites to determine if excess metals pass through the BBB via the circulatory system; and 2) compare biomarkers of neuron function (acetylcholinesterase activity), protection (antioxidant capacity), DNA integrity (DNA fragmentation), lipid integrity (lipid peroxidation) and cell viability (caspase-3 activity) between N. nana foraging at WWTW and reference sites. We found a significantly higher concentration of arsenic in hair (p < 0.05) and brain tissue (p < 0.1) of WWTW bats compared to bats at reference sites. By contrast, acetylcholinesterase activity did not differ in bats among sites and there was no evidence of significant differences in lipid peroxidation, compromised DNA integrity or apoptosis in the brains between WWTW bats and reference site bats. However, total antioxidant capacity was significantly lower in brains of WWTW bats than bats at reference sites suggesting that antioxidant protection may be compromised. Long-term exposure to environmental pollutants at WWTWs may therefore affect cellular processes and protection mechanisms in brains of N. nana bats. It may also affect other mechanisms and functions in the brain such as mitochondrial efficiency and other neurotransmitters but that remains to be tested. (C) 2017 Elsevier B.V. All rights reserved.

Small cell lung cancer (SCLC), an aggressive tumour with very poor prognosis, has a 5 year survival rate of less than 7%. The ubiquitously expressed glucocorticoid receptor (GR) is epigenetically silenced by methylation caused by an accumulation of the DNA methyltransferase 1 (DNMT1) enzyme at the GR promoter region. Application of the highly potent demethylating agent, 5-aza-2’-deoxycytidine (5-aza), restores GR expression causing apoptotic death of SCLC cell lines and xenografts. While highly effective, 5-aza has cytotoxic effects. The aim of this work was to determine whether genistein, a natural bioactive food component able to inhibit DNMT1 activity, is able to modulate GR expression in SCLC at dietary concentrations. Two SCLC cell lines (DMS79 and DMS53) and two controls (A549, non-SCLC and HEK293, GR deficient cell line) were exposed to low concentrations of genistein, similar to dietary concentrations, for either 6 or 72h. Cell lines were evaluated for genistein cytotoxicity using the MTS assay. Quantitative PCR was performed to determine the effect of genistein on GR isoform and DNMT1 expression, GR protein expression was determined by western blot analysis and the ability of genistein to induce apoptosis was assessed by flow cytometric analysis following genistein treatment alone or in combination with the GR antagonist, RU486 or the GR agonist, dexamethasone. MTS cell proliferation assays showed that genistein treatment did not have significant cytotoxic effects on any of the cell lines. Genistein treatment of the SCLC cell line, DMS79, resulted in a significant reduction of DNMT1 expression and a time dependent exposure increased expression of the GR isoforms, GRα and GR-P. These changes at the RNA level were not translated to the protein level. This was not due to excess GR protein being targeted for degradation as proteasome blockade did not affect GR protein levels. Unlike 5-aza treatment which caused a significant increase in the usage of specific GR promoters, genistein treatment did not show a significant increase in usage at 72h. The low concentrations of genistein used in this study induced apoptotic cell death in DMS79 cells. This induction was slightly influenced by co-treatment with RU486. We, therefore conclude that genistein is able to epigenetically modulate GR expression at the mRNA level but not at the protein level. Genistein, at dietary concentrations, is able to induce apoptotic death in a cell line dependent manner, possibly through interaction with the GR.

Hydrogen peroxide (H2O2) is used routinely by the abalone farming industry to induce spawning of adult abalone. The aim of the current study was to quantify DNA integrity of adult hemolymph cells as well as germ cells (oocytes and sperm) with different recovery times between spawning events. In addition, fertilization success of exposed germ cells was quantified. The results indicate that spawning events separated by short recovery (2-6 wk) will not provide sufficient recovery from H2O2-induced DNA fragmentation in adult hemocytes. It is recommended that the industry should ideally allow 6-8 wk between spawning events to prevent accumulation ofDNAstrand breaks in adults over time and to ensure adequate fertilization success to maximize farm production.

Anthropogenic environmental stress imposes increasing pressure on ecosystems. Wastewater treatment works (WWTWs) are major stressors in urban environments and are associated with high levels of pollutants that bioaccumulate and elicit stress responses in animals such as bats. Stress responses are linked with increased metabolic rate and may result in energy store depletion. In this study we measured the effects of WWTWs on energy stores and leptin levels in the insectivorous bat, Neoromicia nana . Energy stores including glucose, glycogen, lipids and proteins were measured in the storage tissues (liver and pectoral muscles) and blood of bats. Further, lactic acid was measured in the pectoral muscles to provide an indirect measure of anaerobic respiration and stress. Leptin, the hormone associated with satiation, and hypoxia inducible factor 1α (Hif-1α) were measured in the interscapular brown adipose tissue (iBrAT). Bats caught at WWTWs exhibited significantly higher pectoral glucose and lactic acid concentrations than bats at reference sites, indicating a stress induced increase in glucose demand and increased reliance on gluconeogenesis to fuel this response. However, glycogen, lipid and protein stores were not depleted in WWTW bats. This may be due to their fat-rich diet at WWTW sites. Moreover, this high polyunsaturated fatty acid (PUFA) diet may be responsible for the unexpectedly high leptin levels in WWTW bats. Lactic acid concentrations were elevated in the pectoral muscles of bats at WWTW sites, indicating some degree of oxidative stress although there was no increase in iBrAT Hif-1α levels. These results show that in the face of environmental stresses, N. nana is able to maintain energy stores.

In this study we tested the hypothesis that the decrease in habitat quality at wastewater treatment works (WWTW), such as limited prey diversity and exposure to the toxic cocktail of pollutants, affect fatty acid profiles of interscapular brown adipose tissue (iBrAT) in bats. Further, the antioxidant capacity of oxidative tissues such as pectoral and cardiac muscle may not be adequate to protect those tissues against reactive molecules resulting from polyunsaturated fatty acid auto-oxidation in the WWTW bats. Bats were sampled at two urban WWTW, and two unpolluted reference sites in KwaZulu-Natal, South Africa. Brown adipose tissue (BrAT) mass was lower in WWTW bats than in reference site bats. We found lower levels of saturated phospholipid fatty acids and higher levels of mono- and polyunsaturated fatty acids in WWTW bats than in reference site bats, while C18 desaturation and n-6 to n-3 ratios were higher in the WWTW bats. This was not associated with high lipid peroxidation levels in pectoral and cardiac muscle. Combined, these results indicate that WWTW bats rely on iBrAT as an energy source, and opportunistic foraging on abundant, pollutant-tolerant prey may change fatty acid profiles in their tissue, with possible effects on mitochondrial functioning, torpor and energy usage.

The Banana Bat, Neoromicia nana, exploits pollution-tolerant chironomids at wastewater treatment works (WWTWs). We investigated how pollutant exposure impacts the detoxification organs, namely the liver and kidney of N. nana. (i) We performed SEM-EDS to quantify metal content and mineral nutrients, and found significant differences in essential metal (Fe and Zn) content in the liver, and significant differences in Cu and one mineral nutrient (K) in the kidneys. (ii) We performed histological analysis and found more histopathological lesions in detoxification organs of WWTW bats. (iii) We calculated hepatosomatic/renalsomatic indices (HSI/RSI) to investigate whole organ effects, and found significant increases in organ size at WWTWs. (iv) We quantified metallothionein 1E (MT1E), using Western Blot immunodetection. Contrary to predictions, we found no significant upregulation of MT1E in bats at WWTWs. Ultimately, N. nana exploiting WWTWs may suffer chronic health problems from sub-lethal damage to organs responsible for detoxifying pollutants.

Wastewater Treatment Works (WWTWs) are a ubiquitous feature of the urban landscape. The Banana Bat, Neoromicia nana specifically exploits the high abundance of chironomid midge prey available at WWTWs but these populations also have higher levels of non-essential metals (Cd, Cr and Ni) in their tissues than bats foraging at unpolluted sites. Pollutant exposure may elicit primary physiological responses such as DNA damage and haematological changes. We investigated whether pollutant exposure from foraging at WWTWs impacts haematological and genotoxic parameters in N. nana. We compared four measures of haematological/genotoxic damage between N. nana foraging at three WWTWs and two unpolluted sites located in KwaZulu-Natal, South Africa: DNA damage measured by the Comet assay, total antioxidant capacity as indicated by the FRAP assay, chromosomal aberration indicated by micronuclei formation and blood oxygen capacity based on haematocrits. There was significantly higher DNA damage in N. nana at WWTWs than in bats from unpolluted sites, suggesting inadequate repair to double stranded DNA breaks. In addition, WWTW bats had a significantly lower antioxidant capacity than bats from unpolluted sites. This suggests that bats at WWTWs may have a diminished capacity to cope with the excess reactive oxidative species (ROS) produced from pollutants such as metals. There was no increase in micronucleus frequency in WWTW bats, indicating that cellular functioning has not yet been disrupted by chemical exposure. Haematocrits, however, were significantly higher in WWTW bats, possibly due to erythrocyte production in response to certain pollutants. Thus, effects of pollutant exposure in bats foraging at WWTWs elicit sub-lethal haematological and genotoxic responses which may pose serious long-term risks. This provides evidence that WWTWs, that are aimed to remove pollutants from the environment, can themselves act as a source of contamination and pose a threat to animals exploiting these habitats.

Marine invertebrates have evolved multiple responses to naturally variable environmental oxygen, all aimed at either maintaining cellular oxygen homeostasis or limiting cellular damage during or after hypoxic or hyperoxic events. We assessed organismal (rates of oxygen consumption and ammonia excretion) and cellular (heat shock protein expression, anti-oxidant enzymes) responses of juvenile and adult abalone exposed to low (~83% of saturation), intermediate (~95% of saturation) and high (~115% of saturation) oxygen levels for one month. Using the Comet assay, we measured DNA damage to determine whether the observed trends in the protective responses were sufficient to prevent oxidative damage to cells. Juveniles were unaffected by moderately hypoxic and hyperoxic conditions. Elevated basal rates of superoxide dismutase, glutathione peroxidase and catalase were sufficient to prevent DNA fragmentation and protein damage. Adults, with their lower basal rate of anti-oxidant enzymes, had increased DNA damage under hypoxic and hyperoxic conditions, indicating that the antioxidant enzymes were unable to prevent oxidative damage under hypoxic and hyperoxic conditions. The apparent insensitivity of juvenile abalone to decreased and increased oxygen might be related to their life history and development in algal and diatom biofilms where they are exposed to extreme diurnal fluctuations in dissolved oxygen levels.

When ectotherms are exposed to high temperatures, cellular oxygen demand increases. When oxygen demand exceeds oxygen availability, animals may experience functional hypoxia regardless of environmental oxygen levels.In the current study, we aimed to assess if oxidative or thermal restrictions exist when winter-acclimated Haliotis midae juveniles are re-acclimated to temperatures within their thermal tolerance range, but with one temperature outside the average daily temperatures they would experience in winter. At each acclimation temperature (14, 16 and 19 degrees C), we also manipulated dissolved oxygen levels to obtain oxygen saturation levels of 82%, 98% and 126%.Our results indicate growth restrictions and hypometabolism at all oxygen treatments at 19 degrees C. Efficiency of mitochondrial respiration, as indicated by an increase in cytochrome c oxidase subunits 1 and 2 (cox1 and cox2) transcript level, was improved at 19 degrees C, 98% oxygen. A change in substrate utilisation, from a glycogen/lipid-driven metabolism to almost exclusively protein-driven metabolism provided the fuel for more effective cellular respiration. A further decrease in metabolic rate at 19 degrees C, 126% oxygen, this time without an increase in cox1 and cox2 transcripts, may indicate some improvement in gas exchange, but without improvement in growth.We propose that 19 degrees C is nearing a long-term limiting temperature for winter-acclimated SA abalone, and that animals survive this condition by re-allocating available energy to survival mechanisms instead of growth. This species, already threatened by over-harvesting, may be further threatened by increases in surface seawater temperatures. (C) 2013 Elsevier Ltd. All rights reserved.

Drinking water quality was investigated at source and corresponding point-of-use in 2 peri-urban areas receiving drinking water either by communal water tanker or by delivery directly from the distribution system to household-based groundtanks with taps. Water quality variables measured were heterotrophic bacteria, total coliforms, E. coli, conductivity, turbidity, pH, and total and residual chlorine. Water quality data were analysed together with an existing epidemiological database to investigate links between microbial quality of drinking water, household demographics, health outcomes, socio-economic status, hygiene and sanitation practices. Groundtank households had better quality drinking water than households using storage containers filled from communal tankers. Uncovered storage containers had the poorest microbial water quality among all storage containers. All stored water did not meet drinking water standards, although mains water did. Households with children under 5 years and using open-topped containers had the poorest water quality overall. Households with groundtanks had the best water quality at point-of-use, but did not have the lowest occurrence of health effects. Although groundtanks were supplied together with urine diversion (UD) toilets and hygiene education, groundtank households showed overall poorer hygiene practices than tanker-supplied households, and some groundtank households with UD toilets preferred to continue using open defecation. Households that practised open defecation had higher levels of E. coli in their drinking water and higher rates of adverse health outcomes. Poorer socio-economic standing and lower educational standard were associated with poorer water quality, poorer hygiene practices and higher rates of diarrhoea and vomiting.

Recent studies of long-distance migratory birds show that behavioural and physiological changes associated with predictable or unpredictable challenges during the annual cycle are distinctively regulated by hormones. Corticosterone is the primary energy regulating hormone in birds. Corticosterone levels are elevated during stresses but they are also modulated seasonally according to environmental conditions and life-history demands. We measured the baseline and stress-induced levels of corticosterone in the barn swallow (Hirundo rustica L.) just before spring and autumn migrations in South Africa and Finland, respectively. Barn swallows completing their pre-breeding moult had low body condition (residual body mass) and high baseline corticosterone levels in the wintering grounds. In contrast, baseline corticosterone levels in Finland were low and not related to residual mass. These data contradict the first prediction of the migration modulation hypothesis (MMH) by showing no association with baseline corticosterone levels and pre-migratory fuelling. Yet, the adrenocortical response to the capture and handling stress was notably blunted in South Africa compared to a strong response in Finland. Further, individuals that had started fuelling in Finland showed a reduced response to the handling stress. Taken together, elevated baseline corticosterone levels and high residual mass may blunt the adrenocortical response in long-distance migrants and aerial feeders such as the barn swallow. This observation lends support to the second prediction of the MMH.