Seasonal synchronization of foodborne outbreaks in the United States, 1996–2017

Modern food systems represent complex dynamic networks vulnerable to foodborne infectious outbreaks difficult to track and control. Seasonal co-occurrences (alignment of seasonal peaks) and synchronization (similarity of seasonal patterns) of infections are noted, yet rarely explored due to their complexity and methodological limitations. We proposed a systematic approach to evaluate the co-occurrence of seasonal peaks using a combination of L-moments, seasonality characteristics such as the timing (phase) and intensity (amplitude) of peaks, and three metrics of serial, phase-phase, and phase-amplitude synchronization. We used public records on counts of nine foodborne infections abstracted from CDC’s FoodNet Fast online platform for the US and ten representative states from 1996 to 2017 (264 months). Based on annualized and trend-adjusted Negative Binomial Harmonic Regression (NBHR) models augmented with the δ-method, we determined that seasonal peaks of Campylobacter, Salmonella, and Shiga toxin-producing Escherichia Coli (STEC) were tightly clustered in late-July at the national and state levels. Phase-phase synchronization was observed between Cryptosporidium and Shigella, Listeria, and Salmonella (ρ = 0.51, 0.51, 0.46; p < 0.04). Later peak timing of STEC was associated with greater amplitude nationally (ρ = 0.50, p = 0.02) indicating phase-amplitude synchronization. Understanding of disease seasonal synchronization is essential for developing reliable outbreak forecasts and informing stakeholders on mitigation and preventive measures.

Publisher Correction: Seasonal synchronization of sleep timing in industrial and pre-industrial societies

An amendment to this paper has been published and can be accessed via a link at the top of the paper

INCIDENCE OF HYDROMETRA IN GOATS AND THERAPEUTIC EFFECTS

The presence of hydrometra was analyzed on five dairy goat farms (one Saanen and four Alpine) in a period of one to three years, from 2013 to 2016. Total of 3,355 goats were scanned by ultrasound for pregnancy diagnosis after breeding season or out-of-season upon hormonal synchronization. Overall incidence of hydrometra was 1.37%. One farm of Saanen goats demonstrated statistically higher incidence of hydro/pyometra as compared to other four Alpine farms (3.25% vs. 0.56%; p <0.001). Seasonal synchronization of anestric goats and occasional outof-season synchronization in nulliparous Saanen goats probably contributed to higher incidence of this pathological condition (7/67; 10.45%), thus leaving unclear if this results can be attributed to breed affinity and/or to intensive reproductive management. Treatment with double prostaglandin injections and antibiotic treatment of hydrometra/pyometra resulted in relatively good conception rate of 64% (16/25). In conclusion, regular ultrasonography 40-70 days after mating or insemination is of crucial importance for intensive farm reproductive management on large dairy goat farms. After the treatment, significant percentage of goats with hydrometra can be successfully rebred.

Analysis of the Southward Wind Shift of ENSO in CMIP5 Models

During the mature phase of El Niño–Southern Oscillation (ENSO) events there is a southward shift of anomalous zonal winds (SWS), which has been suggested to play a role in the seasonal phase locking of ENSO. Motivated by the fact that coupled climate models tend to underestimate this feature, this study examines the representation of the SWS in phase 5 of the Coupled Model Intercomparison Project (CMIP5). It is found that most models successfully reproduce the observed SWS, although the magnitude of the zonal wind stress anomaly is underestimated. Several significant differences between the models with and without the SWS are identified including biases in the magnitude and spatial distribution of precipitation and sea surface temperature (SST) anomalies during ENSO. Multiple-linear regression analysis suggests that the climatological meridional SST gradient as well as anomalous ENSO-driven convective activity over the northwest Pacific both might play a role in controlling the SWS. While the models that capture the SWS also simulate many more strong El Niño and La Niña events peaking at the correct time of year, the overall seasonal synchronization is still underestimated in these models. This is attributed to underestimated changes in warm water volume (WWV) during moderate El Niño events so that these events display relatively poor seasonal synchronization. Thus, while the SWS is an important metric, it is ultimately the magnitude and zonal extent of the wind changes that accompany this SWS that drive the changes in WWV and prime the system for termination.

Simulating the QBO in an Atmospheric General Circulation Model: Sensitivity to Resolved and Parameterized Forcing

The quasi-biennial oscillation (QBO) of tropical stratospheric zonal winds is simulated in an atmospheric general circulation model and its sensitivity to model parameters is explored. Vertical resolution in the lower tropical stratosphere finer than ≈1 km and sufficiently strong forcing by parameterized nonorographic gravity wave drag are both required for the model to exhibit a QBO-like oscillation. Coarser vertical resolution yields oscillations that are seasonally synchronized and driven mainly by gravity wave drag. As vertical resolution increases, wave forcing in the tropical lower stratosphere increases and seasonal synchronization is disrupted, allowing quasi-biennial periodicity to emerge. Seasonal synchronization could result from the form of wave dissipation assumed in the gravity wave parameterization, which allows downward influence by semiannual oscillation (SAO) winds, whereas dissipation of resolved waves is consistent with radiative damping and no downward influence. Parameterized wave drag is nevertheless required to generate a realistic QBO, effectively acting to amplify the relatively weaker mean-flow forcing by resolved waves.