Enhancing livestock vaccination decision-making through rapid diagnostic testing

No abstract available

Validation of Envisat MERIS algorithms for chlorophyll retrieval in a large, turbid and optically-complex shallow lake

The 10-year archive of MEdium Resolution Imaging Spectrometer (MERIS) data is an invaluable resource for studies on lake system dynamics at regional and global scales. MERIS data are no longer actively acquired but their capacity for global scale monitoring of lakes from satellites will soon be re-established through the forthcoming Sentinel-3 Ocean and Land Colour Instrument (OLCI). The development and validation of in-water algorithms for the accurate retrieval of biogeochemical parameters is thus of key importance if the potential of MERIS and OLCI data is to be fully exploited for lake monitoring. This study presents the first extensive validation of algorithms for chlorophyll-a (chl-a) retrieval by MERIS in the highly turbid and productive waters of Lake Balaton, Hungary. Six algorithms for chl-a retrieval from MERIS over optically complex Case 2 waters, including band-difference and neural network architectures, were compared using the MERIS archive for 2007-2012. The algorithms were locally-tuned and validated using in situ chl-a data (n = 289) spanning the five year processed image time series and from all four lake basins. In general, both band-difference algorithms tested (Fluorescence Line Height (FLH) and Maximum Chlorophyll Index (MCI)) performed well, whereas the neural network processors were generally found to much less accurately retrieve in situ chl-a concentrations. The Level 1b FLH algorithm performed best overall in terms of chl-a retrieval (R2 = 0.87; RMSE = 4.19 mg m- 3; relative RMSE = 30.75%) and particularly at chl-a concentrations of ≥ 10 mg m- 3 (R2 = 0.85; RMSE = 4.81 mg m- 3; relative RMSE = 20.77%). However, under mesotrophic conditions (i.e., chl-a < 10 mg m- 3) FLH was outperformed by the locally-tuned FUB/WeW processor (relative FLH RMSE < 10 mg m- 3 = 57.57% versus relative FUB/WeW RMSE < 10 mg m- 3 = 46.96%). An ensemble selection of in-water algorithms is demonstrated to improve chl-a retrievals

Predicting uptake of a malignant catarrhal fever vaccine by pastoralists in northern Tanzania: opportunities for improving livelihoods and ecosystem health

Malignant Catarhal Fever (MCF), caused by a virus transmitted from asymptomatic wildebeest, is a lethal disease in cattle that threatens livestock-based livelihoods and food security in many areas of Africa. Many herd owners reduce transmission risks by moving cattle away from infection hot-spots, but this imposes considerable economic burdens on their households. The advent of a partially-protective vaccine for cattle opens up new options for disease prevention. In a study of pastoral households in northern Tanzania, we use stated preference choice modelling to investigate how pastoralists would likely respond to the availability of such a vaccine. We show a high probability of likely vaccine uptake by herd owners, declining at higher vaccine costs. Acceptance increases with more efficaceous vaccines, in situations where vaccinated cattle are ear-tagged, and where vaccine is delivered through private vets. Through analysis of Normalized Density Vegetation Index (NDVI) data, we show that the reported MCF incidence over 5 years is highest in areas where the mean and interannual varibility in vegetative greeness is relatively low and where herds sizes are smaller. Trends towards lower rainfall and greater landscape-level constraints on cattle movement suggest that MCF avoidance through traditional movement away from wildebeest will become more challenging and that demand for an MCF vaccine will likely increase

The Motheaten Mutation Rescues B Cell Signaling and Development in CD45-deficient Mice

The cytosolic SHP-1 and transmembrane CD45 protein tyrosine phosphatases (PTP) play critical roles in regulating signal transduction via the B cell antigen receptor (BCR). These PTPs differ, however, in their effects on BCR function. For example, BCR-mediated mitogenesis is essentially ablated in mice lacking CD45 (CD45−), but is enhanced in SHP-1–deficient motheaten (me) and viable motheaten (mev) mice. To determine whether these PTPs act independently or coordinately in modulating the physiologic outcome of BCR engagement, we assessed B cell development and signaling in CD45-deficient mev (CD45−/SHP-1−) mice. Here we report that the CD45−/SHP-1− cells undergo appropriate induction of protein kinase activity, mitogen-activated protein kinase activation, and proliferative responses after BCR aggregation. However, BCR-elicited increases in the tyrosine phosphorylation of several SHP-1–associated phosphoproteins, including CD19, were substantially enhanced in CD45−/SHP-1−, compared to wild-type and CD45− cells. In addition, we observed that the patterns of cell surface expression of μ, δ, and CD5, which distinguish the PTP-deficient from normal mice, are largely restored to normal levels in the double mutant animals. These findings indicate a critical role for the balance of SHP-1 and CD45 activities in determining the outcome of BCR stimulation and suggest that these PTPs act in a coordinate fashion to couple antigen receptor engagement to B cell activation and maturation

The sero-epidemiology of Neospora caninum in cattle in northern Tanzania

Neospora caninum is a protozoan intracellular parasite of animals with a global distribution. Dogs act as definitive hosts, with infection in cattle leading to reproductive losses. Neosporosis can be a major source of income loss for livestock keepers, but its impacts in sub-Saharan Africa are mostly unknown. This study aimed to estimate the seroprevalence and identify risk factors for N. caninum infection in cattle in northern Tanzania, and to link herd-level exposure to reproductive losses. Serum samples from 3,015 cattle were collected from 380 households in 20 villages between February and December 2016. Questionnaire data were collected from 360 of these households. Household coordinates were used to extract satellite derived environmental data from open-access sources. Sera were tested for the presence of N. caninum antibodies using an indirect ELISA. Risk factors for individual-level seropositivity were identified with logistic regression using Bayesian model averaging (BMA). The relationship between herd-level seroprevalence and abortion rates was assessed using negative binomial regression. The seroprevalence of N. caninum exposure after adjustment for diagnostic test performance was 21.5% [95% Credibility Interval (CrI) 17.9–25.4]. The most important predictors of seropositivity selected by BMA were age greater than 18 months [Odds ratio (OR) = 2.17, 95% CrI 1.45–3.26], the local cattle population density (OR = 0.69, 95% CrI 0.41–1.00), household use of restricted grazing (OR = 0.72, 95% CrI 0.25–1.16), and an increasing percentage cover of shrub or forest land in the environment surrounding a household (OR = 1.37, 1.00–2.14). There was a positive relationship between herd-level N. caninum seroprevalence and the reported within-herd abortion rate (Incidence Rate Ratio = 1.03, 95% CrI 1.00–1.06). Our findings suggest N. caninum is likely to be an important cause of abortion in cattle in Tanzania. Management practices, such as restricted grazing, are likely to reduce the risk of infection and suggest contamination of communal grazing areas may be important for transmission. Evidence for a relationship between livestock seropositivity and shrub and forest habitats raises questions about a potential role for wildlife in the epidemiology of N. caninum in Tanzania

Waves of endemic foot-and-mouth disease in eastern Africa suggest feasibility of proactive vaccination approaches

Livestock production in Africa is key to national economies, food security and rural livelihoods, and > 85% of livestock keepers live in extreme poverty. With poverty elimination central to the Sustainable Development Goals, livestock keepers are therefore critically important. Foot-and-mouth disease is a highly contagious livestock disease widespread in Africa that contributes to this poverty. Despite its US$2.3 billion impact, control of the disease is not prioritized: standard vaccination regimens are too costly, its impact on the poorest is underestimated, and its epidemiology is too weakly understood. Our integrated analysis in Tanzania shows that the disease is of high concern, reduces household budgets for human health, and has major impacts on milk production and draft power for crop production. Critically, foot-and-mouth disease outbreaks in cattle are driven by livestock-related factors with a pattern of changing serotype dominance over time. Contrary to findings in southern Africa, we find no evidence of frequent infection from wildlife, with outbreaks in cattle sweeping slowly across the region through a sequence of dominant serotypes. This regularity suggests that timely identification of the epidemic serotype could allow proactive vaccination ahead of the wave of infection, mitigating impacts, and our preliminary matching work has identified potential vaccine candidates. This strategy is more realistic than wildlife-livestock separation or conventional foot-and-mouth disease vaccination approaches. Overall, we provide strong evidence for the feasibility of coordinated foot-and-mouth disease control as part of livestock development policies in eastern Africa, and our integrated socioeconomic, epidemiological, laboratory and modelling approach provides a framework for the study of other disease systems

Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

An Antiapoptotic Neuroprotective Role for Neuroglobin

Cell death associated with mitochondrial dysfunction is common in acute neurological disorders and in neurodegenerative diseases. Neuronal apoptosis is regulated by multiple proteins, including neuroglobin, a small heme protein of ancient origin. Neuroglobin is found in high concentration in some neurons, and its high expression has been shown to promote survival of neurons in vitro and to protect brain from damage by both stroke and Alzheimer’s disease in vivo. Early studies suggested this protective role might arise from the protein’s capacity to bind oxygen or react with nitric oxide. Recent data, however, suggests that neither of these functions is likely to be of physiological significance. Other studies have shown that neuroglobin reacts very rapidly with cytochrome c released from mitochondria during cell death, thus interfering with the intrinsic pathway of apoptosis. Systems level computational modelling suggests that the physiological role of neuroglobin is to reset the trigger level for the post-mitochondrial execution of apoptosis. An understanding of the mechanism of action of neuroglobin might thus provide a rational basis for the design of new drug targets for inhibiting excessive neuronal cell death