Seroprevalence of contagious bovine pleuropneumonia (CBPP) in cattle from Karamoja region, North-eastern Uganda.

BACKGROUND: Contagious bovine pleuropneumonia [CBPP] is a transboundary animal disease of cattle caused by Mycoplasma mycoides subsp. mycoides [Mmm]. CBPP causes severe economic losses to livestock producers in sub-Saharan Africa mainly due to high mortality, morbidity, reduction in productivity as well as livestock trade restrictions. This study aimed at determining seroprevalence of Mmm in cattle from Karamoja region, north-eastern Uganda; data that are required to design and implement risk based CBPP control program. METHODS: We randomly collected blood samples from 2,300 cattle spread across Karamoja region. Serum was extracted and screened for antibodies against Mycoplasma mycoides subsp. mycoides [Mmm] using the competitive enzyme linked immunosorbent assay [cELISA]. RESULTS: A quarter [25.4%; 95% CI: 23.7-27.3] of the screened cattle [n = 2,300] were sero-positive for Mmm. Amudat and Kaabong districts recorded the lowest [12.3%] and highest [30.7%] Mmm seroprevalence respectively. Increasing age, overnight stay in cattle kraals and location [certain districts, villages, herds and sub counties] of the cattle herds, the factors that promote animal commingling, were the most significant risk factors of seroconversion with Mmm. CONCLUSION: Results from this study indicated a higher seroprevalence of Mmm in Karamoja region cattle herds. This could be due to the increased frequency of CBPP outbreaks in recent years. To be effective, CBPP vaccination programs should target high risk herds along the international borders and other hotspot areas [e.g., parishes or sub counties] where cattle commingling is high.

Age-associated alterations of brain mitochondria energetics.

The study aimed to explore the role of age-associated elevated cytosolic Ca2+ in changes of brain mitochondria energetic processes. Two groups of rats, young adults (4 months) and advanced old (24 months), were evaluated for potential alterations of mitochondrial parameters, the oxidative phosphorylation (OxPhos), membrane potential, calcium retention capacity, activity of glutamate/aspartate carrier (aralar), and ROS formation. We demonstrated that the brain mitochondria of older animals have a lower resistance to Ca2+ stress with resulting consequences. The suppressed complex I OxPhos and decreased membrane potential were accompanied by reduction of the Ca2+ threshold required for induction of mPTP. The Ca2+ binding sites of mitochondrial aralar mediated a lower activity of old brain mitochondria. The altered interaction between aralar and mPTP may underlie mitochondrial dysregulation leading to energetic depression during aging. At the advanced stages of aging, the declined metabolism is accompanied by the diminished oxidative background.

Odour mapping and air quality analysis of a wastewater treatment plant at a seaside tourist area.

Although wastewater treatment plants (WWTPs) play a fundamental role in protecting the aquatic environment as they prevent organic matter, nutrients and other pollutants from reaching the natural ecosystems, near residential areas they can generate unpleasant smells and noise. The plant studied in the present work is in a seaside tourist area in the Valencian Community, Spain. The main aim was to detect any possible perceptible H2S concentrations from the WWTP by experimental measurement campaigns (including sensor readings and olfactometry measurements by two experts) plus mathematical modelling. After a thorough data analysis of the essential variables involved, such as wind speed, wind direction and H2S concentrations (the main odorant) and comparing their temporal patterns, it was found that the probability of affecting the residential area was highest from June to August before noon and in the late evening. The hourly H2S concentration, influent flow rate and temperature showed a positive correlation, the strongest (R2 = 0.89) being the relationship between the H2S concentration and influent flow rate. These two variables followed a similar daily pattern and indicated that H2S was emitted when influent wastewater was being pumped into the biological reactor. The H2S median concentration at the source of the emission was below 1393.865 µg/m3 (1 ppm), although concentrations 10 times higher were occasionally recorded. The observed H2S peak-to-mean ratio (1 min to 1 h of integration times) ranged from 1.15 to 16.03. This ratio and its attenuation with distance from the source depended on the atmospheric stability. Both H2S concentrations and variability were considerably reduced after submerging the inlet. The AERMOD modelling framework and applying the peak-to-mean ratio were used to map the peak H2S concentration and determine the best conditions to eliminate the unpleasant odour.

The impact of seasonal and event-based infiltration on transition metals (Cu, Ni, Co) in tropical cave drip water.

RATIONALE: The first-row transition metals Cu, Ni, and Co show a strong binding affinity to natural organic matter. Compared to dissolved elements and stable water isotopes, they may be transported rapidly through the soil and host rock into caves in response to infiltration events. This study aims to assess the potential of transition metal ratios as indicators for infiltration changes in response to the seasonal and/or event-based rainfall variation. METHODS: We developed a protocol to analyze Cu, Ni, and Co in the cave drip water using collision cell ICP-QMS without extensive sample pretreatment. The high Ca matrix leads to significant isobaric interferences on all isotope masses. Our method includes a correction of these matrix effects and yields results with comparable accuracy and reproducibility to other published methods. We applied this protocol to drip water samples from Larga Cave (Puerto Rico) covering at least two full annual cycles between 2014 and 2019 on a bimonthly scale. RESULTS: The analysis of external reference materials yielded a reproducibility between 4.7% and 9.2% (relative standard deviation), validating the accuracy of the matrix correction method. The limit of detection is <0.04 ppb for Cu, <0.02 ppb for Ni, and <0.008 ppb for Co. The analysis of drip water samples from Larga Cave reveals pronounced changes of several orders of magnitude in all Element (El) to Ca, Cu/Ni, and Cu/Co ratios in response to seasonal infiltration changes. In addition, we observe a partly even stronger response after major tropical storms and heavy precipitation events of the period of record, for example, tropical storm "Bertha" (2014) and the category 5 hurricanes "Irma" and "Maria" (both 2017). CONCLUSIONS: Transition metal ratios can be accurately measured in cave drip waters with high Ca matrix. At our tropical site, these are promising tracers of infiltration changes in response to changes in the amount of rainfall, providing the first step toward tropical cyclone reconstruction using trace elements in speleothems.

Phylogeographic analysis of foot-and-mouth disease virus serotype O dispersal and associated drivers in East Africa.

The continued endemicity of foot and mouth disease virus (FMDV) in East Africa has significant implications for livestock production and poverty reduction, yet its complex epidemiology in endemic settings remains poorly understood. Identifying FMDV dispersal routes and drivers of transmission is key to improved control strategies. Environmental heterogeneity and anthropogenic drivers (e.g., demand for animal products) can impact viral spread by influencing host movements. Here, we utilized FMDV serotype O VP1 genetic sequences and corresponding spatiotemporal data in order to (i) infer the recent dispersal history, and (II) investigate the impact of external factors (cattle density, human population density, proximity to livestock markets, and drought) on dispersal velocity, location, and direction of FMDV serotype O in East Africa. We identified statistical evidence of long-distance transmission events, and we found that FMDV serotype O tends to remain circulating in areas of high cattle density, high human population density, and in close proximity to livestock markets. The latter two findings highlight the influence of anthropogenic factors on FMDV serotype O spread in this region. These findings contribute to the understanding of FMDV epidemiology in East Africa and can help guide improved control measures.

Rabies in Uganda: rabies knowledge, attitude and practice and molecular characterization of circulating virus strains.

BACKGROUND: Rabies is a deadly preventable viral disease that affects all warm-blooded animals and widespread in many regions including Africa. The disease remains of major public health importance in Uganda. The purpose of this study was to establish Knowledge, Attitude, Practice (KAP) of Rabies in Moyo and Ntoroko districts and to characterize Rabies virus (RABV) strains from seven districts of Uganda with consistent prevalence of rabies. METHODS: KAP survey data were collected based on animal biting history by interviewing the head of the veterinary departments, the medical centers and selected households from the study sites. Data were obtained from 84 households in Ntoroko and Moyo districts. Thirty-five (35) brain samples were collected from bovine, dogs, goats, foxes, jackals ad sheep between 2011 and 2013. Samples were tested using fluorescent antibody test (FAT), One step RT-PCR (following RNA extraction) and partial RABV N gene was sequenced by Sanger method before phylogenetic and phylogeographic analyses of sequences. RESULTS: Scarcity of post-exposure prophylaxis services in the health centers was noted. Poor attitude of wound washing and deficiency of knowledge on how to handle wounds related to dog bites and the significance among household participants lacked. There is a high risk of rabies infection due to a limited dog's vaccination. Dog biting episodes in humans were of 75.00 and 62.50% in Moyo and Ntoroko districts respectively. Twenty-seven (27) samples tested positive for rabies by FAT and PCR. Ugandan sequences were closely related (97% nucleotide id) to the rabies virus sequences from Tanzania, Rwanda, Burundi, Nigeria, Central African Republic and Sudan with both the "Africa 1A" and "Africa 1B" RABV clades represented. A putative new clade 1D was also detected. CONCLUSIONS: Rabies remains a public health hazard in Uganda. There is urgent need to establish advocacy programs in both schools and communities to curtail the spread of rabies. Increasing the knowledge regarding wound washing, post-exposure prophylaxis and dogs vaccination would enhance prevention of rabies. A strong collaboration between medical and veterinary sectors under a one health platform is required to ensure sufficient preventative services to the communities.

Molecular detection and phylogenetic analysis of lumpy skin disease virus from outbreaks in Uganda 2017-2018.

BACKGROUND: Lumpy skin disease (LSD) is an infectious viral disease of cattle caused by a Capripoxvirus. LSD has substantial economic implications, with infection resulting in permanent damage to the skin of affected animals which lowers their commercial value. In Uganda, LSD is endemic and cases of the disease are frequently reported to government authorities. This study was undertaken to molecularly characterize lumpy skin disease virus (LSDV) strains that have been circulating in Uganda between 2017 and 2018. Secondly, the study aimed to determine the phylogenetic relatedness of Ugandan LSDV sequences with published sequences, available in GenBank. RESULTS: A total of 7 blood samples and 16 skin nodule biopsies were screened for LSDV using PCR to confirm presence of LSDV nucleic acids. PCR positive samples were then characterised by amplifying the GPCR gene. These amplified genes were sequenced and phylogenetic trees were constructed. Out of the 23 samples analysed, 15 were positive for LSDV by PCR (65.2%). The LSDV GPCR sequences analysed contained the unique signatures of LSDV (A11, T12, T34, S99, and P199) which further confirmed their identity. Sequence comparison with vaccine strains revealed a 12 bp deletion unique to Ugandan outbreak strains. Phylogenetic analysis indicated that the LSDV sequences from this study clustered closely with sequences from neighboring East African countries and with LSDV strains from recent outbreaks in Europe. It was noted that the sequence diversity amongst LSDV strains from Africa was higher than diversity from Eurasia. CONCLUSION: The LSDV strains circulating in Uganda were closely related with sequences from neighboring African countries and from Eurasia. Comparison of the GPCR gene showed that outbreak strains differed from vaccine strains. This information is necessary to understand LSDV molecular epidemiology and to contribute knowledge towards the development of control strategies by the Government of Uganda.

Spatial and temporal distribution of lumpy skin disease outbreaks in Uganda (2002-2016).

BACKGROUND: Lumpy skin disease (LSD) is a devastating transboundary viral disease of cattle which causes significant loss in production. Although this disease has been reported in Uganda and throughout East Africa, there is almost no information about its epidemiology, spatial or spatio-temporal distribution. We carried out a retrospective study on the epidemiology of LSD in Uganda between the years 2002 and 2016, using data on reported outbreaks collected monthly by the central government veterinary administration. Descriptive statistics were computed on frequency of outbreaks, number of cases, vaccinations and deaths. We evaluated differences in the number of reported outbreaks across different regions (agro-ecological zones), districts, months and years. Spatial, temporal and space-time scan statistics were used to identify possible epidemiological clusters of LSD outbreaks. RESULTS: A total of 1161 outbreaks and 319,355 cases of LSD were reported from 55 out of 56 districts of Uganda. There was a significant difference in incidence between years (P = 0.007) and across different regions. However, there was no significant difference in the number of outbreaks per month (P = 0.443). The Central region reported the highest number of outbreaks (n = 418, 36%) followed by Eastern (n = 372, 32%), Southwestern (n = 140, 12%), Northern (n = 131, 11%), Northeastern (n = 37, 3%), Western (n = 41, 4%) and Northwestern (n = 22, 2%) regions. Several endemic hotspots for the circulation of LSD were identified in the Central and Eastern regions using spatial cluster analyses. Outbreaks in endemic hotspots were less seasonal and had strikingly lower mortality and case-fatality rates than the other regions, suggesting an underlying difference in the epidemiology and impact of LSD in these different zones. CONCLUSION: Lumpy Skin disease is endemic in Uganda, with outbreaks occurring annually in all regions of the country. We identified potential spatial hotspots for LSD outbreaks, underlining the need for risk-based surveillance to establish the actual disease prevalence and risk factors for disease maintenance. Space-time analysis revealed that sporadic LSD outbreaks tend to occur both within and outside of endemic areas. The findings from this study will be used as a baseline for further epidemiological studies for the development of sustainable programmes towards the control of LSD in Uganda.

6-Hydroxydopamine impairs mitochondrial function in the rat model of Parkinson's disease: respirometric, histological, and behavioral analyses.

Mitochondrial defects have been shown to be associated with the pathogenesis of Parkinson's disease (PD). Yet, experience in PD research linking mitochondrial dysfunction, e.g., deregulation of oxidative phosphorylation, with neuronal degeneration and behavioral changes is rather limited. Using the 6-hydroxydopamine (6-OHDA) rat model of PD, we have investigated the potential role of mitochondria in dopaminergic neuronal cell death in the substantia nigra pars compacta by high-resolution respirometry. Mitochondrial function was correlated with the time course of disease-related motor behavior asymmetry and dopaminergic neuronal cell loss, respectively. Unilateral 6-OHDA injections (>2.5 µg/2 µl) into the median forebrain bundle induced an impairment of oxidative phosphorylation due to a decrease in complex I activity. This was indicated by increased flux control coefficient. During the period of days 2-21, a progressive decrease in respiratory control ratio of up to -58 % was observed in the lesioned compared to the non-lesioned substantia nigra of the same animals. This decrease was associated with a marked uncoupling of oxidative phosphorylation. Mitochondrial dysfunction, motor behavior asymmetry, and dopaminergic neuronal cell loss correlated with dosage (1.25-5 µg/2 µl). We conclude that high-resolution respirometry may allow the detection of distinct mitochondrial dysfunction as a suitable surrogate marker for the preclinical assessment of potential neuroprotective strategies in the 6-OHDA model of PD.

Sero-prevalence of syphilis and associated risk factors among pregnant women attending antenatal care at an urban-poor health centre in Kampala, Uganda: a cross-sectional study.

Introduction: syphilis and its outcomes remain a healthcare system burden with adverse consequences such as stillbirths, neonatal deaths and spontaneous abortions among others. The situation might have worsened because the COVID-19 pandemic has caused a major attention drift from other diseases. Additionally, much as testing for syphilis is a routine practice among pregnant mothers, its proportion is not known in urban health care setting. A study to determine the prevalence of syphilis among pregnant mothers in an urban poor setting is warranted. Methods: a cross-sectional study was conducted among pregnant women who attended antenatal care at Kawaala Health Centre IV in Kampala Capital City between December 2019 to March 2020. Informed consent was sought from study participants prior to data collection using structured questionnaires. Whole blood was collected and tested using SD Bioline HIV/syphilis duo rapid test kit (SD Standard Diagnostics, INC, Korea). Data analysis was done using STATA 14.2. Results: one thousand one hundred and sixty-nine pregnant women participated in the study, with a mean age of 25 years. About 27% of them had completed only primary-level education. Approximately 6% of the participants were HIV seropositive. The prevalence of syphilis was 5.9% (69/1169). HIV positivity (aOR: 4.13, 95%CI: 2.05-8.34), elevated blood pressure (aOR: 2.84, 95%CI: 1.42-5.69), and status of previous pregnancy (aOR: 0.21, 95%CI: 0.05-0.89) were significant predictors of the risk of syphilis among pregnant women in this setting. Conclusion: the prevalence of syphilis among pregnant women in urban poor settings is not low and so must not be underestimated. The potential drivers of syphilis among pregnant women are HIV, elevated blood pressure, and status of previous pregnancy. There should be increased awareness about routine syphilis testing among pregnant mothers attending antenatal care.

Acaricide resistance status of livestock ticks from East and West Africa and in vivo efficacy of acaricides to control them.

Through a collaborative effort across six Sub-Saharan African countries, using recognized international assessment techniques, 23 stocks of three tick species (Rhipicephalus microplus, Rhipicephalus appendiculatus and Amblyomma variegatum) of economic importance for rural small holder farming communities from East and West Africa were collected from cattle, and evaluated in in vitro larval packet tests (LPT). The results demonstrated medium to high resistance to chlorfenvinphos and amitraz across species. Rhipicephalus microplus demonstrated high level alpha-cypermethrin and cypermethrin resistance. Stocks of A. variegatum (West Africa) and R. appendiculatus (Uganda) demonstrated medium level ivermectin resistance. The four least susceptible stocks (East and West African R. microplus, A. variegatum and R. appendiculatus) were taken into in vivo controlled cattle studies where fipronil was found effective against West and East African R. microplus isolates although persistent efficacy failed to reach 90%. Cymiazole and cypermethrin, and ivermectin based acaricides were partially effective against R. microplus without persistent efficacy. Flumethrin spray-on killed A. variegatum within 72 h for up to 10 days posttreatment, however product application was directly to tick attachment sites, which may be impractical under field conditions. A flumethrin pour-on formulation on goats provided persistent efficacy against A. variegatum for up to one-month. Therapeutic control was achieved against R. appendiculatus through weekly spraying cattle with flumethrin, amitraz or combined cymiazole and cypermethrin. A fipronil pour-on product offered four-week residual control against R. appendiculatus (with slow onset of action). Few studies have assessed and directly compared acaricidal activity in vitro and in vivo. There was some discordance between efficacy indicated by LPT and in vivo results. This observation calls for more research into accurate and affordable assessment methods for acaricide resistance. No single active or product was effective against all three tick species, emphasising the need for the development of alternative integrated tick management solutions.

Complex effects of 17ß-estradiol on mitochondrial function.

Existing literature on estradiol indicates that it affects mitochondrial functions at low micromolar concentrations. Particularly blockade of the permeability transition pore (PTP) or modulation of the enzymatic activity of one or more complexes of the respiratory chain were suspicious. We prepared mitoplasts from rat liver mitochondria (RLM) to study by single-channel patch-clamp techniques the PTP, and from rat astrocytes to study the potassium BK-channel said to modulate the PTP. Additionally, we measured respiration of intact RLM. After application of 17ß-estradiol (ßE) our single-channel results reveal a transient increase of activity of both, the BK-channel and the PTP followed by their powerful inhibition. Respiration measurements demonstrate inhibition of the Ca(2+)-induced permeability transition, as well, though only at higher concentrations (≥30µM). At lower concentrations, we observed an increase of endogenous- and state 2-respiration. Furthermore, we show that ßE diminishes the phosphorylating respiration supported by complex I-substrates (glutamate/malate) or by the complex II-substrate succinate. Taken together the results suggest that ßE affects mitochondria by several modes, including partial inhibition of the activities of ion channels of the inner membrane and of respiration. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).

The control of brain mitochondrial energization by cytosolic calcium: the mitochondrial gas pedal.

This review focuses on problems of the intracellular regulation of mitochondrial function in the brain via the (i) supply of mitochondria with ADP by means of ADP shuttles and channels and (ii) the Ca(2+) control of mitochondrial substrate supply. The permeability of the mitochondrial outer membrane for adenine nucleotides is low. Therefore rate dependent concentration gradients exist between the mitochondrial intermembrane space and the cytosol. The existence of dynamic ADP gradients is an important precondition for the functioning of ADP shuttles, for example CrP-shuttle. Cr at mM concentrations instead of ADP diffuses from the cytosol through the porin pores into the intermembrane space. The CrP-shuttle isoenzymes work in different directions which requires different metabolite concentrations mainly caused by dynamic ADP compartmentation. The ADP shuttle mechanisms alone cannot explain the load dependent changes in mitochondrial energization, and a complete model of mitochondrial regulation have to account the Ca(2+) -dependent substrate supply too. According to the old paradigmatic view, Ca(2+) (cyt) taken up by the mitochondrial Ca(2+) uniporter activates dehydrogenases within the matrix. However, recently it was found that Ca(2+) (cyt) at low nM concentrations exclusively activates the state 3 respiration via aralar, the mitochondrial glutamate/aspartate carrier. At higher Ca(2+) (cyt) (> 500 nM), brain mitochondria take up Ca(2+) for activation of substrate oxidation rates. Since brain mitochondrial pyruvate oxidation is only slightly influenced by Ca(2+) (cyt) , it was proposed that the cytosolic formation of pyruvate from its precursors is tightly controlled by the Ca(2+) dependent malate/aspartate shuttle. At low (50-100 nM) Ca(2+) (cyt) the pyruvate formation is suppressed, providing a substrate limitation control in neurons. This so called "gas pedal" mechanism explains why the energy metabolism of neurons in the nucleus suprachiasmaticus could be down-regulated at night but activated at day as a basis for the circadian changes in Ca(2+) (cyt) . It also could explain the energetic disadvantages caused by altered Ca(2+) (cyt) at mitochondrial diseases and neurodegeneration.

Prevalence of African swine fever virus in apparently healthy domestic pigs in Uganda.

BACKGROUND: African swine fever (ASF) is a contagious viral disease which can cause up to 100% mortality among domestic pigs leading to serious socio-economic impact on people's livelihoods. ASF is endemic in Uganda and there is paucity of information on the epidemiology of the disease. The major aim of this study was to determine the seroprevalence and prevalence of African swine fever virus (ASFV) in apparently healthy slaughter pigs at Wambizi slaughterhouse in Kampala city, Uganda. We also estimated the presence of ASFV antibodies and circulating viral antigens in pigs from selected districts of Uganda during targeted surveillance. We analysed 540 and 181 blood samples collected from slaughter pigs and pigs from targeted surveillance districts respectively. RESULTS: The prevalence of ASFV in slaughter pigs was 52.96% (95% CI, 48.75-57.14) and 11.5% (95% CI, 9.06-14.45) by ELISA and PCR respectively. In surveillance districts, the proportion of ASFV positive pigs was 53.59% (95% CI, 46.33-60.71) and 0.55% (95% CI, 0.1-3.06) by ELISA and PCR respectively. CONCLUSION: The study has found out a high seroprevalence of ASFV antibodies in apparently healthy slaughter pigs and also a high proportion of ASFV antibody seropositive pigs in surveyed districts in Uganda indicating exposure to ASFV. However, there was a lower prevalence of ASFV infection implying that there could be low virulent strains of ASFV circulating in domestic pigs in Uganda which requires further investigation.

Cytosolic Ca2+ regulates the energization of isolated brain mitochondria by formation of pyruvate through the malate-aspartate shuttle.

The glutamate-dependent respiration of isolated BM (brain mitochondria) is regulated by Ca2+(cyt) (cytosolic Ca2+) (S0.5=225±22 nM) through its effects on aralar. We now also demonstrate that the α-glycerophosphate-dependent respiration is controlled by Ca2+(cyt) (S0.5=60±10 nM). At higher Ca2+(cyt) (>600 nM), BM accumulate Ca2+ which enhances the rate of intramitochondrial dehydrogenases. The Ca2+-induced increments of state 3 respiration decrease with substrate in the order glutamate>α-oxoglutarate>isocitrate>α-glycerophosphate>pyruvate. Whereas the oxidation of pyruvate is only slightly influenced by Ca2+(cyt), we show that the formation of pyruvate is tightly controlled by Ca2+(cyt). Through its common substrate couple NADH/NAD+, the formation of pyruvate by LDH (lactate dehydrogenase) is linked to the MAS (malate-aspartate shuttle) with aralar as a central component. A rise in Ca2+(cyt) in a reconstituted system consisting of BM, cytosolic enzymes of MAS and LDH causes an up to 5-fold enhancement of OXPHOS (oxidative phosphorylation) rates that is due to an increased substrate supply, acting in a manner similar to a 'gas pedal'. In contrast, Ca2+(mit) (intramitochondrial Ca2+) regulates the oxidation rates of substrates which are present within the mitochondrial matrix. We postulate that Ca2+(cyt) is a key factor in adjusting the mitochondrial energization to the requirements of intact neurons.

Mid- to late Holocene sea-level rise recorded in Hells Bells 234U/238U ratio and geochemical composition.

Hells Bells are underwater secondary carbonates discovered in sinkholes (cenotes) southeast of Cancun on the north-eastern Yucatán peninsula, Mexico. These authigenic calcite precipitates, reaching a length of up to 4 m, most likely grow in the pelagic redoxcline. Here we report on detailed 230Th/U-dating and in-depth geochemical and stable isotope analyses of specimens from cenotes El Zapote, Maravilla and Tortugas. Hells Bells developed since at least ~ 8000 years ago, with active growth until present day. Initial (234U/238U) activity ratios (δ234U0) in Hells Bells calcite decreas from 55 to 15‰ as sea level converges toward its present state. The temporal evolution of the geochemistry and isotope composition of Hells Bells calcites thus appears to be closely linked to sea-level rise and reflects changing hydrological conditions (desalinization) of the aquifer. We suggest that decelerated leaching of excess 234U from the previously unsaturated bedrock traces Holocene relative sea-level rise. Considering this proxy, the resulting mean sea-level reconstruction contains half as much scatter, i.e. improves by a factor of two, when compared to previously published work for the period between 8 and 4 ky BP.

Ecological and Anthropogenic Spatial Gradients Shape Patterns of Dispersal of Foot-and-Mouth Disease Virus in Uganda.

Using georeferenced phylogenetic trees, phylogeography allows researchers to elucidate interactions between environmental heterogeneities and patterns of infectious disease spread. Concordant with the increasing availability of pathogen genetic sequence data, there is a growing need for tools to test epidemiological hypotheses in this field. In this study, we apply tools traditionally used in ecology to elucidate the epidemiology of foot-and-mouth disease virus (FMDV) in Uganda. We analyze FMDV serotype O genetic sequences and their corresponding spatiotemporal metadata from a cross-sectional study of cattle. We apply step selection function (SSF) models, typically used to study wildlife habitat selection, to viral phylogenies to show that FMDV is more likely to be found in areas of low rainfall. Next, we use a novel approach, a resource gradient function (RGF) model, to elucidate characteristics of viral source and sink areas. An RGF model applied to our data reveals that areas of high cattle density and areas near livestock markets may serve as sources of FMDV dissemination in Uganda, and areas of low rainfall serve as viral sinks that experience frequent reintroductions. Our results may help to inform risk-based FMDV control strategies in Uganda. More broadly, these tools advance the phylogenetic toolkit, as they may help to uncover patterns of spread of other organisms for which genetic sequences and corresponding spatiotemporal metadata exist.

Perceptions and practices of farmers of indigenous poultry towards Salmonella infections in North-Central Nigeria.

Background: Salmonella infections continue to be of global concern to poultry health, productivity, and public health. About 44% of the poultry in Nigeria are indigenous and kept in close interaction with farmers who are mostly rural dwellers and have limited access to veterinary and extension services. Aim: The perceptions and practices of farmers of indigenous poultry toward Salmonella infections were assessed to obtain and document baseline data that can be used to create awareness among farmers about these infections and their attendant public health implications. Methods: A cross-sectional approach using a multistage sampling method was used in this survey. A total of 419 farmers keeping indigenous poultry were interviewed using a pre-tested electronic questionnaire in three randomly selected states within North-Central Nigeria. Data were analyzed using descriptive and regression analysis. Results: Out of the 419 respondents, 138 (32.9%), 141 (33.7%), and 140 (33.4%) were from Benue, Kwara, and Plateau States, respectively. Of the 419, 55.4% were females, 40.8% were above 40 years, and 35.8% have over 10 years of farming experience. The majority of the poultry are not housed (58.5%) and farmers predominantly rear chickens (51.8%). Also, 49.9% of the birds were 1-6 months with 41.5% of the flock sizes being 11-20. Respondents had a poor level of perception toward Salmonella infection as the majority did not know that Salmonella affects poultry (89.3%) and that Salmonella infections are zoonotic (94.5%). Significant (p = 0.000) associations existed between categorized perception score and age, educational status, family size, and farming experience of farmers. There were significant (p = 0.000) associations of categorized practice scores with gender, age, education status, family size, and farming experience of farmers. Conclusion: This study has revealed the poor perception of farmers on Salmonella infections and has highlighted their practices. There is a need to raise awareness about these infections to improve indigenous poultry health and productivity as well as public health.

Solar forcing of early Holocene droughts on the Yucatán peninsula.

A speleothem record from the north-eastern Yucatán peninsula (Mexico) provides new insights into the tropical hydro-climate of the Americas between 11,040 and 9520 a BP on up to sub-decadal scale. Despite the complex atmospheric reorganization during the end of the last deglaciation, the dominant internal leading modes of precipitation variability during the late Holocene were also active during the time of record. While multi-decadal variations were not persistent, Mesoamerican precipitation was dominated by changes on the decadal- and centennial scale, which may be attributed to ENSO activity driven by solar forcing. Freshwater fluxes from the remnant Laurentide ice sheet into the Gulf of Mexico and the North Atlantic have additionally modulated the regional evaporation/precipitation balance. In particular, this study underlines the importance of solar activity on tropical and subtropical climate variability through forcing of the tropical Pacific, providing a plausible scenario for observed recurrent droughts on the decadal scale throughout the Holocene.