The role of veterinary epidemiology and veterinary services in complying with the World Trade Organization SPS agreement

The agreement on the application of sanitary and phytosanitary measures (SPS agreement) was one of the major products of the GATT's Uruguay round of multilateral trade negotiations, signed in Marrakesh on 15 April 1994. This agreement and others are part of the treaty that established the World Trade Organization (WTO). The WTO superseded the GATT as the umbrella organization for international trade (WTO, 1998a). The SPS agreement's main intent is to provide guidelines and provisions to member countries to facilitate trade while taking measures to protect human, animal or plant life or health. The agreement dictates that all sanitary measures must be scientifically based and not more restrictive than required to avoid the risk identified. The agreement recommends the use of international standards from the World Organization for Animal Health (OIE), Codex Alimentarius (CAC) and the International Plant Protection Convention (IPPC) as the basis for import requirements. If a country chooses to apply more restrictive measures than those in the international standards, it has to justify its position through a risk analysis, thus avoiding the use of sanitary and phytosanitary measures as unjustified barriers to trade. More than ever, veterinary services worldwide are faced with having to fulfill a crucial role in protecting their country's animal health status, provide sound surveillance information on the occurrence of diseases within their territories, and conduct scientifically valid risk analyses to establish justified import requirements. During the past two decades, most countries have experienced resource reduction in their veterinary services. The effect of these policies has been severe, in many cases leading to an inability of veterinary services to conduct their disease prevention and control duties. There is a clear inconsistency between the demands placed on veterinary services and the current level of funding and support they are receiving, particularly in the developing world. This paper analyzes the implications in complying with the SPS agreement and explores the role of veterinary epidemiology in developing viable alternatives that can enhance the veterinary services' ability to perform under the current economic reality. The key provisions of the SPS agreement are regionalization, risk analysis, harmonization, equivalence and transparency. The paper focuses on the contribution of epidemiology in each of these areas in the effective implementation of the SPS agreement.     

Test of the Root Zone Water Quality Model (RZWQM) for predicting runoff of atrazine, alachlor and fenamiphos species from conventional-tillage corn mesoplots

The Root Zone Water Quality Model (RZWQM) is a comprehensive, integrated physical, biological and chemical process model that simulates plant growth and movement of water, nutrients and pesticides in a representative area of an agricultural system. We tested the ability of RZWQM to predict surface runoff losses of atrazine, alachlor, fenamiphos and two fenamiphos oxidative degradates against results from a 2-year mesoplot rainfall simulation experiment. Model inputs included site-specific soil properties and weather, but default values were used for most other parameters, including pesticide properties. No attempts were made to calibrate the model except for soil crust/seal hydraulic conductivity and an adjustment of pesticide persistence in near-surface soil. Approximately 2.5 (+/- 0.9), 3.0 (+/- 0.8) and 0.3 (+/- 0.2)% of the applied alachlor, atrazine and fenamiphos were lost in surface water runoff, respectively. Runoff losses in the 'critical' events--those occurring 24 h after pesticide application--were respectively 91 (+/- 5), 86 (+/- 6) and 96 (+/- 3)% of total runoff losses for these pesticides. RZWQM adequately predicted runoff water volumes, giving a predicted/observed ratio of 1.2 (+/- 0.5) for all events. Predicted pesticide concentrations and loads from the 'critical' events were generally within a factor of 2, but atrazine losses from these events were underestimated, which was probably a formulation effect, and fenamiphos losses were overestimated due to rapid oxidation. The ratios of predicted to measured pesticide concentrations in all runoff events varied between 0.2 and 147, with an average of 7. Large over-predictions of pesticide runoff occurred in runoff events later in the season when both loads and concentrations were small. The normalized root mean square error for pesticide runoff concentration predictions varied between 42 and 122%, with an average of 84%. Pesticide runoff loads were predicted with a similar accuracy. These results indicate that the soil-water mixing model used in RZWQM is a robust predictor of pesticide entrainment and runoff.     

Tomato yellow leaf curl virus in the Dominican Republic: Characterization of an Infectious Clone, Virus Monitoring in Whiteflies, and Identification of Reservoir Hosts

ABSTRACT Epidemics of tomato yellow leaf curl disease (TYLCD) in the Dominican Republic in the early to mid-1990s resulted in catastrophic losses to processing tomato production. As part of an integrated management approach to TYLCD, the complete nucleotide sequence of a full-length infectious clone of an isolate of Tomato yellow leaf curl virus (TYLCV) from the Dominican Republic (TYLCV-[DO]) was determined. The TYLCV-[DO] genome was nearly identical in sequence (>97%) and genome organization to TYLCV isolates from Israel and Cuba. This established that TYLCV-[DO] is a bonafide TYLCV isolate (rather than a recombinant virus, such as isolates from Israel [Mild], Portugal, Japan, and Iran), and provided further evidence for the introduction of the virus from the eastern Mediterranean. A reduction in the incidence of TYLCV in the northern and southern processing tomato production areas of the Dominican Republic has been associated with the implementation of a mandatory 3-month whitefly host-free period (including tomato, common bean, cucurbits, eggplant, and pepper). Monitoring TYLCV levels in whiteflies, by polymerase chain reaction with TYLCV-specific primers, established that the incidence of TYLCV decreased markedly during the host-free period, and then gradually increased during the tomato-growing season. In contrast, TYLCV persisted in whiteflies and tomato plants in an area in which the host-free period was not implemented. Surveys for TYLCV reservoir hosts, conducted to identify where TYLCV persists during the host-free period, revealed symptomless infections in a number of weed species. The implications of these findings for TYLCV management in the Dominican Republic are discussed.     

Effect of ENSO on the distribution and concentration of catches and reproductive activity of anchovy Engraulis ringens in northern Chile

Anchovy makes up 90% of pelagic fishery catches in northern Chile. For the present work, anchovy (Engraulis ringens, Jenyns 1842) catches between 1997 and 2016 were analyzed to determine changes in distribution, concentration, and reproductive behavior before, during, and after ENSO events, using spatial indexes: gravity center (GC), inertia, coverage (CI), Gini index, and gonadosomatic index (GI). At the start of ENSO, anchovy catches increased and concentrated along the coast (rising Gini index), while CI decreased. During ENSO, Gini decreased, registering a southward displacement of the GC and smaller catches. In the long run, anchovy occupied lesser area (<CI) starting from 2008, concentrating in coastal areas. It developed a size structure composed mainly of specimens smaller than 17.0 cm. In addition, specimens < 12.0 cm were positively correlated with thermal anomalies, CI and MEI, reaching more than 60% of the catches during the 1997–1998 and 2015–2016 ENSO cycles. Results suggest that the warm phase of ENSO alters the anchovies’ reproductive activity, delaying its onset up to 4 weeks, and reducing GI intensity to 50%, due to increased participation in the reproductive process of individuals 12.0–13.5 cm. Therefore, large‐scale environmental processes, such as ENSO, significantly affect size structure and contribute to reduction of occupied area and higher reproductive activity of small‐size anchovies.     

Cuticular calcium penetration is directly related to the area covered by calcium within droplet spread area

Calcium penetration from salt solutions of calcium chloride and calcium acetate was measured through isolated tomato fruit (Solanum lycopersicum L., cultivar ‘Panovy’) cuticles after 4, 24, and 48 h. Droplet spread area (volume = 1 μL) and the area ultimately covered with calcium were determined with a scanning electron microscope which has an integrated energy dispersive X-ray microanalysis system. An ethoxylated rapeseed oil surfactant (RSO 5) was used for inducing different degrees of droplet spread and together with different calcium concentrations of the solutions to vary the concentration gradient in the penetration experiments. As a rule, penetration of calcium from CaCl₂ was higher than that of Ca(CH₃COO)₂. The addition of RSO 5 to salt solutions resulted in enhanced calcium penetration in comparison to unformulated solutions. However, extending penetration time from 4 to 48 h predominantly did not enhance the penetrated calcium amount significantly. Droplet spread area was enhanced up to 4-fold after adding RSO 5, whereas the area ultimately covered with calcium did not exceed twice as much. This resulted in lower percentage area covered by calcium in droplet footprints from formulated solutions in comparison to solutions without addition of RSO 5. Correlation analyses showed that penetration was not related to droplet spread area but significantly correlated with the area covered by calcium. These observations were true for unformulated calcium salts as well as for calcium solutions with addition of RSO 5. Therefore, the area ultimately covered with calcium or even other xenobiotics within a droplet footprint should be considered in developing mathematical models to simulate active ingredient (a.i.) penetration.     

Effect of incubation temperature on the embryonic development and yolk‐sac larvae of the Pacific red snapper Lutjanus peru (Nichols & Murphy, 1922)

The effect of incubation temperature on embryonic development and yolk‐sac larva of the Pacific red snapper Lutjanus peru were evaluated by testing the effect of 26, 28 and 30°C, as this is the natural thermal interval reported during the spawning season of Pacific red snapper in the Gulf of California, Mexico. Sixteen developmental stages were observed. The incubation temperature affected the rate of development and time to hatching, being shorter at 30 than at 26°C, but no significant effect (P < 0.05) on larval length at hatching was registered. The depletion rate of yolk sac and oil globule was affected by incubation temperature particularly during the first 12 h post hatching (hph). At the end of the experiment (48 hph), significantly (P < 0.05) larger larvae were recorded at 26°C (TL = 3.22 ± 0.01 mm) than at 28° (TL = 3.01 ± 0.02 mm) and 30°C (TL = 2.97 ± 0.05 mm). Incubation of newly fertilized eggs at 26°C produces larger larvae, which may help to improve feeding efficiency and survival during first feeding.     

Effects of a dairy product fortified with multiple micronutrients and omega-3 fatty acids on birth weight and gestation duration in pregnant Chilean women

OBJECTIVE: To test the hypothesis that maternal food fortification with omega-3 fatty acids and multiple micronutrients increases birth weight and gestation duration, as primary outcomes. DESIGN: Non-blinded, randomised controlled study. SETTING: Pregnant women received powdered milk during their health check-ups at 19 antenatal clinics and delivered at two maternity hospitals in Santiago, Chile. SUBJECT: Pregnant women were assigned to receive regular powdered milk (n = 477) or a milk product fortified with multiple micronutrients and omega-3 fatty acids (n = 495). RESULTS: Intention-to-treat analysis showed that mean birth weight was higher in the intervention group than in controls (65.4 g difference, 95% confidence interval (CI) 5-126 g; P = 0.03) and the incidence of very preterm birth (0.80 just for mean birth weight and birth length in the on-treatment analysis; birth length in that analysis had a difference of 0.57 cm (95% CI 0.19-0.96 cm; P = 0.003). CONCLUSIONS: The new intervention resulted in increased mean birth weight. Associations with gestation duration and most secondary outcomes need a larger sample size for confirmation.     

Understanding overbidding: using the neural circuitry of reward to design economic auctions

We take advantage of our knowledge of the neural circuitry of reward to investigate a puzzling economic phenomenon: Why do people overbid in auctions? Using functional magnetic resonance imaging (fMRI), we observed that the social competition inherent in an auction results in a more pronounced blood oxygen level-dependent (BOLD) response to loss in the striatum, with greater overbidding correlated with the magnitude of this response. Leveraging these neuroimaging results, we design a behavioral experiment that demonstrates that framing an experimental auction to emphasize loss increases overbidding. These results highlight a role for the contemplation of loss in understanding the tendency to bid "too high." Current economic theories suggest overbidding may result from either "joy of winning" or risk aversion. By combining neuroeconomic and behavioral economic techniques, we find that another factor, namely loss contemplation in a social context, may mediate overbidding in auctions.