An analysis of the possible effects of the 2001 foot and mouth disease epidemic on grass pollen concentrations in the Midlands,UK

The 2001 grass pollen season in the United Kingdom was notably severe. An epidemic of foot and mouth disease (FMD) occurred in the UK during February and spread through the country during the summer. The media claimed that the control measures of culling infected animals and the restricted movement of stock, led to reduced grazing allowing pastures to flower more than in previous years. This study aimed to examine whether the severity was due only to weather factors or if the control measures also contributed. Three pollen sites from the FMD-affected Midlands region were investigated and compared with two sites from regions unaffected for differences in pollen catches, culling levels and weather. The June pollen catch in the Midlands was particularly high but this pattern also features in areas such as Cambridge in the East that were minimally affected by the epidemic. In most of the catchment areas affected by FMD the quantity of animals culled was less than 10% of the total livestock. In areas where culling was concentrated we can assume that there would have been some localized affect on the pollen levels. The results show that the main influencing variable on the 2001 grass pollen counts in the Midlands was the weather and that culling due to the foot and mouth epidemic did not exert an important influence at the regional level.     

An analysis of the possible effects of the 2001 foot and mouth disease epidemic on grass pollen concentrations in the Midlands, UK

The 2001 grass pollen season in the United Kingdom was notably severe. An epidemic of foot and mouth disease (FMD) occurred in the UK during February and spread through the country during the summer. The media claimed that the control measures of culling infected animals and the restricted movement of stock, led to reduced grazing allowing pastures to flower more than in previous years. This study aimed to examine whether the severity was due only to weather factors or if the control measures also contributed. Three pollen sites from the FMD-affected Midlands region were investigated and compared with two sites from regions unaffected for differences in pollen catches, culling levels and weather. The June pollen catch in the Midlands was particularly high but this pattern also features in areas such as Cambridge in the East that were minimally affected by the epidemic. In most of the catchment areas affected by FMD the quantity of animals culled was less than 10% of the total livestock. In areas where culling was concentrated we can assume that there would have been some localized affect on the pollen levels. The results show that the main influencing variable on the 2001 grass pollen counts in the Midlands was the weather and that culling due to the foot and mouth epidemic did not exert an important influence at the regional level.     

Transmission parameters of the 2001 foot and mouth epidemic in Great Britain

Despite intensive ongoing research, key aspects of the spatial-temporal evolution of the 2001 foot and mouth disease (FMD) epidemic in Great Britain (GB) remain unexplained. Here we develop a Markov Chain Monte Carlo (MCMC) method for estimating epidemiological parameters of the 2001 outbreak for a range of simple transmission models. We make the simplifying assumption that infectious farms were completely observed in 2001, equivalent to assuming that farms that were proactively culled but not diagnosed with FMD were not infectious, even if some were infected. We estimate how transmission parameters varied through time, highlighting the impact of the control measures on the progression of the epidemic. We demonstrate statistically significant evidence for assortative contact patterns between animals of the same species. Predictive risk maps of the transmission potential in different geographic areas of GB are presented for the fitted models.     

Animal disease and human trauma: the psychosocial implications of the 2001 UK foot and mouth disease disaster

The 2001 UK foot and mouth disease (FMD) crisis is commonly understood to have been a nonhuman animal problem, an economic industrial crisis that was resolved after eradication. By using a different lens, a longitudinal ethnographic study of the health and social consequences of the epidemic, the research reported here indicates that 2001 was a human tragedy as well as an animal one. In a diary-based study, it can be seen that life after the FMD crisis was accompanied by distress, feelings of bereavement, fear of a new disaster, loss of trust in authority and systems of control, and the undermining of the value of local knowledge. Diverse groups experienced distress well beyond the farming community. Such distress remained largely invisible to the range of “official” inquiries into the disaster. That an FMD epidemic of the scale of 2001 could happen again in a developed country is a deeply worrying prospect, but it is to be hoped that contingency plans are evolving along with enhanced understanding of the human, animal, and financial cost.     

Analytic approximation of spatial epidemic models of foot and mouth disease

The effect of spatial heterogeneity in epidemic models has improved with computational advances, yet far less progress has been made in developing analytical tools for understanding such systems. Here, we develop two classes of second-order moment closure methods for approximating the dynamics of a stochastic spatial model of the spread of foot and mouth disease. We consider the performance of such ‘pseudo-spatial’ models as a function of R₀, the locality in disease transmission, farm distribution and geographically-targeted control when an arbitrary number of spatial kernels are incorporated. One advantage of mapping complex spatial models onto simpler deterministic approximations lies in the ability to potentially obtain a better analytical understanding of disease dynamics and the effects of control. We exploit this tractability by deriving analytical results in the invasion stages of an FMD outbreak, highlighting key principles underlying epidemic spread on contact networks and the effect of spatial correlations.     

Short term effects of weather on hand, foot and mouth disease

Background

Hand, foot, and mouth disease (HFMD) outbreaks leading to clinical and fatal complications have increased since late 1990s; especially in the Asia Pacific Region. Outbreaks of HFMD peaks in the warmer season of the year, but the underlying factors for this annual pattern and the reasons to the recent upsurge trend have not yet been established. This study analyzed the effect of short-term changes in weather on the incidence of HFMD in Singapore.

Methods

The relative risks between weekly HFMD cases and temperature and rainfall were estimated for the period 2001–2008 using time series Poisson regression models allowing for over-dispersion. Smoothing was used to allow non-linear relationship between weather and weekly HFMD cases, and to adjust for seasonality and long-term time trend. Additionally, autocorrelation was controlled and weather was allowed to have a lagged effect on HFMD incidence up to 2 weeks.

Results

Weekly temperature and rainfall showed statistically significant association with HFMD incidence at time lag of 1–2 weeks. Every 1°C increases in maximum temperature above 32°C elevated the risk of HFMD incidence by 36% (95% CI = 1.341–1.389). Simultaneously, one mm increase of weekly cumulative rainfall below 75 mm increased the risk of HFMD by 0.3% (CI = 1.002–1.003). While above 75 mm the effect was opposite and each mm increases of rainfall decreased the incidence by 0.5% (CI = 0.995–0.996). We also found that a difference between minimum and maximum temperature greater than 7°C elevated the risk of HFMD by 41% (CI = 1.388–1.439).

Conclusion

Our findings suggest a strong association between HFMD and weather. However, the exact reason for the association is yet to be studied. Information on maximum temperature above 32°C and moderate rainfall precede HFMD incidence could help to control and curb the up-surging trend of HFMD.     

Short-term effects of meteorological factors on children hand,foot and mouth disease in Guangzhou,China

Hand, foot and mouth disease (HFMD) is a contagious viral illness that commonly affects infants and children. The underlying risk factors have not yet been systematically examined. This study analyzed the short-term effects of meteorological factors on children HFMD in Guangzhou, China. Daily count of HFMD among children younger than 15 years and meteorological variables from 2009 to 2011 were collected to construct the time series. A generalized additive model was applied to estimate the effects of meteorological factors on HFMD occurrence, after adjusting for long-term trend, seasonal trend, day of week, and public holidays. A negative association between temperature and children HFMD occurrence was observed at lag days 1–3, with the relative risk (RR) for a 1 °C increase on lag day 2 being 0.983 (95 % confidence intervals (CI) 0.977 to 0.989); positive effect was found for temperature at lag days 5–9, with the highest effect at lag day 6 (RR?=?1.014, 95 % CI 1.006 to 1.023). Higher humidity was associated with increased HFMD at lag days 3–10, with the highest effect at lag day 8 (RR?=?1.009 for 1 % increase in relative humidity, 95 % CI 1.007 to 1.010). And we also observed significant positive effect for rainfall at lag days 4 and 8 (RR?=?1.001, 95 % CI 1.000 to 1.002) for 1-mm increase. Subgroup analyses showed that the positive effects of temperature were more pronounced among younger children. This study suggests that meteorological factors might be important predictors of children HFMD occurrence in Guangzhou.     

Reproducibility between counts of airborne allergenic pollen from two cities in the East Midlands,UK

Historically in the East Midlands, UK, airborne pollen has been monitored in two cities, Derby and Leicester, situated 41 km (25 miles) apart. The aim of the present study was to compare aerobiological data from both sites to determine if a forecast based on data from one site would be sufficient for both, and to address the wider issue of reproducibility between geographically separated sites. Pollen types recorded could be split into two groups according to annual abundance, maximum daily concentration and the number of high count days. Six taxa made up the abundant group; ash, birch, grass, oak, nettle-type and yew-type, representing 90 and 88% of the total air spora for Derby and Leicester, respectively. Three consecutive years of grass and nettle pollen data are presented, supported by one year of abundant tree pollen data. There were highly significant positive correlations between the counts obtained. Line charts showing the average number of pollen grains m⁻³ air day⁻¹ show similar trends, and Bland–Altman plots show little discrepancy between the amounts of pollen counted on any given day. Each day was classified according to the UK accepted threshold levels for grass. Weighted kappa statistics showed substantial or almost perfect agreement between the forecast classifications. With the caveat that this would not apply in a region with restrictions to air flow such as a mountain range or with extreme fluctuations such as a coastline site, this study suggests that data from a single site is suitable for forecasting a distance of up to 41 km.     

The construction and analysis of epidemic trees with reference to the 2001 UK foot-and-mouth outbreak

The case-reproduction ratio for the spread of an infectious disease is a critically important concept for understanding dynamics of epidemics and for evaluating impact of control measures on spread of infection. Reliable estimation of this ratio is a problem central to epidemiology and is most often accomplished by fitting dynamic models to data and estimating combinations of parameters that equate to the case-reproduction ratio. Here, we develop a novel parameter-free method that permits direct estimation of the history of transmission events recoverable from detailed observation of a particular epidemic. From these reconstructed 'epidemic trees', case-reproduction ratios can be estimated directly. We develop a bootstrap algorithm that generates percentile intervals for these estimates that shows the procedure to be both precise and robust to possible uncertainties in the historical reconstruction. Identifying and 'pruning' branches from these trees whose occurrence might have been prevented by implementation of more stringent control measures permits estimation of the possible efficacy of these alternative measures. Examination of the cladistic structure of these trees as a function of the distance of each case from its infection source reveals useful insights about the relationship between long-distance transmission events and epidemic size. We demonstrate the utility of these methods by applying them to data from the 2001 foot-and-mouth disease outbreak in the UK.     

98 例手足口病流行特征与临床分析

目前, 我国手足口病患儿有增多流行趋势。为了解该病的流行特征及临床特点, 提高对该病的认识, 防止其暴发流行及病情恶化, 采用描述性流行病学方法, 对我院2008 年5 ― 6 月收治的98 例住院患儿进行研究分析。发病患儿多数为1 ～5 岁( 80. 61% ) 的农村或郊区儿童。散居儿童( 72 例, 73. 47% ) 多于群居儿童( 26 例, 26. 53% ) 。临床表现主要为发热和皮疹, 皮疹部位以手、足、口、臀、膝等为主。98 例患儿均有皮疹, 其中88 例( 89. 80% ) 患儿发热。实验室检查血常规, 白细胞无明显变化或升高。反转录-聚合酶链反应( RTPCR)检测报告, 肠道病毒71 型( EV71) 或柯萨奇病毒A16 型( CA16) 阳性共78 例, 其中EV71 74 例。对于本病, 常规抗病毒及对症治疗效果好, 患儿均在1 周左右治愈, 但是如不及时诊治, 可能出现病程延长或各种并发症, 导致病情恶化甚至死亡。故除对患儿进行积极的隔离治疗和疫点处理外, 有效的健康教育对该病的预防能起到事半功倍的效果。     

手足口病流行病学及防治的研究概况

手足口病(hand foot and mouth disease,HFMD)是由多种肠道病毒引起的常见传染病,以婴幼儿发病为主。肠道病毒71型(EV71)与柯萨奇病毒A16(Cox A16)感染交替出现,成为手足口病的主要病原体,全球流行地区较为广泛,世界大部分地区均有此病流行报道,全年均可发病,5-10月为流行高峰期。因个别地方出现少数患儿中枢神经系统、呼吸系统和循环系统损害,经全力抢救无效死亡,引起社会各界广泛关注。目前,手足口病已经成为严重的公共卫生问题,应采取综合性防治措施,切实预防和控制手足口病的流行和爆发流行。     

Epidemic of hand, foot and mouth disease in Gifu Prefecture in 1978

During the period from May to August, 1978, an epidemic of hand, foot and mouth disease (HFMD) occurred in Gifu prefecture. Epidemiological, virological and serological investigations were performed. Cases involved ranged from 0 to 31 years of age, and 80.2% of them were under 5 years of age. The incidence of HFMD with neurological complication (3.7%) was lower than that in 1973. Enterovirus 71 (EV71) was isolated from 83 of 108 cases (75.9%) and a significant rise in the neutralization antibody titer against the isolate was found in 14 of 25 cases (56%). Thus, it was confirmed that the causative agent of the epidemic of HFMD in Gifu prefecture in 1978 was enterovirus 71.     

2011—2014年百色市重症手足口病流行病学及病原学分析

目的了解2011—2014年百色市重症手足口病的流行病学及病原学特点,为预防和控制重症手足口病提供依据。方法收集2011—2014年百色市重症手足口病疫情资料,进行描述性流行病学分析;采用实时荧光定量PCR方法对手足口病重症病例标本进行肠道病毒通用型、肠道病毒71型和柯萨奇病毒A16型核酸检测。结果2011—2014年百色市共报告手足口病105 900例,其中重症手足口病537例,重症率为0.51%;死亡35例,病死率为0.03%。重症手足口病发病主要集中在每年的4—5月;3岁以下重症病例占重症病例总数的88.27%,男女性别比为1.44∶1;散居儿童是主要的发病人群(75.98%);患者主要集中在平果县、田东县、田阳县、右江区等右江河谷一带;重症手足口病阳性患者中,肠道病毒71型占77.51%,柯萨奇病毒A16型占5.15%,其他肠道病毒占17.34%。结论 2011—2014年百色市重症手足口病多发于3岁以下的散居儿童,发病季节主要集中在4—5月,病原体以肠道病毒71型为主。