Habitat shifts in response to predation risk are constrained by competition within a grazing guild

Predators can affect prey not only by killing them, but also by causing them to alter their behavior, including patterns of habitat selection. Prey can reduce the risk of predation by moving to habitats where predators are less likely to detect them, less likely to attack, or less likely to succeed. The interaction of such responses to risk with other ecological processes remains relatively unstudied, but in some cases, changes in habitat use to avoid predation may be constrained by competition: larger, dominant competitors should respond freely to predation risk, but the responses of smaller, subordinate competitors may be constrained by the responses of dominant competitors. For large grazing herbivores, an alternative hypothesis proposes that smaller prey species are vulnerable to more predators, and thus should respond more strongly to predation risk. Here, we tested these two hypotheses with 775 observations of habitat selection by four species of obligate grazers (zebra, wildebeest, puku and oribi) in the immediate presence or absence of four large carnivores (lion, spotted hyena, African wild dog and cheetah) in three ecosystems (Greater Liuwa, Greater Kafue and Luangwa Valley). Patterns of predation within this set were described by observation of 1,105 kills. Our results support the hypothesis that responses to predation risk are strongest for larger, dominant competitors. Even though zebras were killed least often, they showed the strongest shift into cover when carnivores were present. Wildebeest, puku and oribi showed weaker habitat shifts, even though they were more frequently killed. These patterns remained consistent in models that controlled for differences in the hunting mode of the predator (stalking, coursing, or intermediate) and for differences among ecosystems. There was no evidence that smaller species were subject to predation by a broader set of predators. Instead, smaller prey were killed often by smaller predators, and larger prey were killed often by larger predators. Broadly, our results show that responses to predation risk interact with interspecific competition. Accounting for such interactions should help to explain the considerable variation in the strength of responses to predation risk that has been observed

Taenia solium Infections in a Rural Area of Eastern Zambia-A Community Based Study

Taenia solium taeniosis/cysticercosis is a zoonotic infection endemic in many developing countries, with humans as the definitive host (taeniosis) and pigs and humans as the intermediate hosts (cysticercosis). When humans act as the intermediate host, the result can be neurocysticercosis, which is associated with acquired epilepsy, considerable morbidity and even mortality. In Africa, most studies have been carried out in pigs with little or no data in humans available. In this human study, conducted in a rural community in Eastern Zambia, prevalences for taeniosis and cysticercosis were determined at 6.3% and 5.8% respectively, indicating the hyperendemicity of the area. Cysticercosis infection was strongly related with age, with a significant increase in prevalence occurring in individuals from the age of 30 onward. A collected tapeworm was confirmed to be T. solium. Risk factors associated with the transmission and maintenance of the parasite such as free roaming pigs, households without latrines, backyard slaughter of pigs without inspection and consumption of undercooked pork were also present. The findings of this work have identified the need for further research in the transmission dynamics and the burden that this infection has on the resources of poor local people

Confirmation by necropsy of a high prevalence of porcine cysticercosis in a rural district of Madagascar

Neurocysticercosis is recognized as an important health issue in the Malagasy population. To date, investigations into prevalence of infection with the causative agent, Taenia solium, in the parasite's natural animal intermediate hosts, have relied on serological methods which have been found to be non-specific. We determined the prevalence of porcine cysticercosis among pigs from a contiguous area of the Betafo and Mandoto administrative districts, Vakinankaratra Region, Madagascar. One hundred and four slaughter-weight pigs were examined by detailed necropsy examination including slicing of the heart, tongue, masseter muscles, diaphragm and carcase musculature. Thirty-seven animals (35.6%) were found infected with T. solium, representing one of the highest rates of infection ever reported, worldwide. These findings highlight the importance of T. solium in Madagascar and support the need for increased efforts to prevent the parasite's transmission to reduce its burden on the health of the Malagasy population

The Zambian Preterm Birth Prevention Study (ZAPPS): Cohort characteristics at enrollment [version 2; referees: 2 approved]

Background:Sub-Saharan Africa bears a disproportionate burden of preterm birth and other adverse outcomes. A better understanding of the demographic, clinical, and biologic underpinnings of these adverse outcomes is urgently needed to plan interventions and inform new discovery.  Methods:The Zambian Preterm Birth Prevention Study (ZAPPS) is a prospective observational cohort established at the Women and Newborn Hospital (WNH) in Lusaka, Zambia. We recruit pregnant women from district health centers and the WNH and offer ultrasound examination to determine eligibility. Participants receive routine obstetrical care, lab testing, midtrimester cervical length measurement, and serial fetal growth monitoring. At delivery, we assess gestational age, birthweight, vital status, and sex and assign a delivery phenotype. We collect blood, urine, and vaginal swab specimens at scheduled visits and store them in an on-site biorepository. In September 2017, enrollment of the ZAPPS Phase 1 – the subject of this report – was completed. Phase 2 – which is limited to HIV-uninfected women – reopened in January 2018.  Results:Between August 2015 and September 2017, we screened 1784 women, of whom 1450 (81.2%) met inclusion criteria and were enrolled. The median age at enrollment was 27 years (IQR 23–32) and thee median gestational age was 16 weeks (IQR 13–18). Among parous women (N=866; 64%), 21% (N=182) reported a prior miscarriage, 49% (N=424) reported a prior preterm birth, and 13% (N=116) reported a prior stillbirth. The HIV seroprevalence was 24%. Discussion:We have established a large cohort of pregnant women and newborns at the WHN to characterize the determinants of adverse birth outcomes in Lusaka, Zambia. Our overarching goal is to elucidate biological mechanisms in an effort to identify new strategies for early detection and prevention of adverse outcomes. We hope that findings from this cohort will help guide future studies, clinical care, and policy

Development and external validation of machine learning algorithms for postnatal gestational age estimation using clinical data and metabolomic markers

Background Accurate estimates of gestational age (GA) at birth are important for preterm birth surveillance but can be challenging to obtain in low income countries. Our objective was to develop machine learning models to accurately estimate GA shortly after birth using clinical and metabolomic data. Methods We derived three GA estimation models using ELASTIC NET multivariable linear regression using metabolomic markers from heel-prick blood samples and clinical data from a retrospective cohort of newborns from Ontario, Canada. We conducted internal model validation in an independent cohort of Ontario newborns, and external validation in heel prick and cord blood sample data collected from newborns from prospective birth cohorts in Lusaka, Zambia and Matlab, Bangladesh. Model performance was measured by comparing model-derived estimates of GA to reference estimates from early pregnancy ultrasound. Results Samples were collected from 311 newborns from Zambia and 1176 from Bangladesh. The best-performing model accurately estimated GA within about 6 days of ultrasound estimates in both cohorts when applied to heel prick data (MAE 0.79 weeks (95% CI 0.69, 0.90) for Zambia; 0.81 weeks (0.75, 0.86) for Bangladesh), and within about 7 days when applied to cord blood data (1.02 weeks (0.90, 1.15) for Zambia; 0.95 weeks (0.90, 0.99) for Bangladesh). Conclusions Algorithms developed in Canada provided accurate estimates of GA when applied to external cohorts from Zambia and Bangladesh. Model performance was superior in heel prick data as compared to cord blood data

Animal influence on water, sanitation and hygiene measures for zoonosis control at the household level: A systematic literature review

Neglected zoonotic diseases (NZDs) have a significant impact on the livelihoods of the world’s poorest populations, which often lack access to basic services. Water, sanitation and hygiene (WASH) programmes are included among the key strategies for achieving the World Health Organization’s 2020 Roadmap for Implementation for control of Neglected Tropical Diseases (NTDs). There exists a lack of knowledge regarding the effect of animals on the effectiveness of WASH measures. This review looked to identify how animal presence in the household influences the effectiveness of water, hygiene and sanitation measures for zoonotic disease control in low and middle income countries; to identify gaps of knowledge regarding this topic based on the amount and type of studies looking at this particular interaction

Effect of african potato (hypoxis hemerocallidea) extract on oxidative stress induced by chloroquine in albino rats

This study evaluated the antioxidant and protective effects of Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm ('African potato') water extract (HH) against chloroquine induced oxidative stress in albino rats. Chloroquine has been known to generate oxidative stress when used for different types of treatment like malaria, prophylactic treatment and treatment of rheumatoid arthritis. There is also biomedical evidence that African potato corm extracts possess anti-inflammatory,anti-nociceptive, antioxidant and anti-diabetic properties in vivo and in vitro. Twenty five albino rats were used for this study and were divided into five groups; chloroquine control group (CQ) received choroquine (25 mg/kg every day), normal control group (NC) received distilled water every day, normal experimental group (HYP) received water decoction of corm (10 ml/kg), two experimental groups (E1 and E2) received chloroquine (25 mg/kg) plus 10 ml and 20 ml of extract kg-1 body weightrespectively. The experiment was conducted for a period of 30 days after which the rats were killed under ether anaesthesia, blood collected and liver removed for the measurement of thiobarbituric acid reactive substance, serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, reduced glutathione, superoxide dismutase, glutathione per-oxidase and tocopherol. The result showed thatthe water extract maintained the normal non enzymatic and enzymatic anti oxidants status and thus protected the rats in two experimental groups from oxidative stress generated due to chloroquine in dose dependant manner (

Effect Of African Potato ( Hypoxis Hemerocallidea ) Extract On Oxidative Stress Induced By Chloroquine In Albino Rats

This study evaluated the antioxidant and protective effects of Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm ('African potato') water extract (HH) against chloroquine induced oxidative stress in albino rats. Chloroquine has been known to generate oxidative stress when used for different types of treatment like malaria, prophylactic treatment and treatment of rheumatoid arthritis. There is also biomedical evidence that African potato corm extracts possess anti-inflammatory, anti-nociceptive, antioxidant and anti-diabetic properties in vivo and in vitro. Twenty five albino rats were used for this study and were divided into five groups; chloroquine control group (CQ) received choroquine (25 mg/kg every day), normal control group (NC) received distilled water every day, normal experimental group (HYP) received water decoction of corm (10 ml/kg), two experimental groups (E1 and E2) received chloroquine (25 mg/kg) plus 10 ml and 20 ml of extract kg-1 body weight respectively. The experiment was conducted for a period of 30 days after which the rats were killed under ether anaesthesia, blood collected and liver removed for the measurement of thiobarbituric acid reactive substance, serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, reduced glutathione, superoxide dismutase, glutathione per-oxidase and tocopherol. The result showed that the water extract maintained the normal non enzymatic and enzymatic anti oxidants status and thus protected the rats in two experimental groups from oxidative stress generated due to chloroquine in dose dependant manner (P≤0.001). The extract also increased the levels of reduced glutathione and tocopherol in HYP group (P≤0.0001). It appears that under normal condition, H hemerocallidea acts as booster plant to antioxidant system increasing the levels of GSH and tocopherol. Thus from this study it can be concluded that H. hemerocallidea has potentials to protect the organism from oxidative stress generated by chloroquine and also to strengthen the antioxidant system under normal conditions