Assessing human risk of illness with West Nile virus mosquito surveillance data to improve public health preparedness

Surveillance for West Nile virus (WNV) and other mosquito‐borne pathogens involves costly and time‐consuming collection and testing of mosquito samples. One difficulty faced by public health personnel is how to interpret mosquito data relative to human risk, thus leading to a failure to fully exploit the information from mosquito testing. The objective of our study was to use the information gained from historic West Nile virus mosquito testing to determine human risk relative to mosquito infection and to assess the usefulness of our mosquito infection forecasting models to give advance warning. We compared weekly mosquito infection rates from 2004 to 2013 to WNV case numbers in Illinois. We then developed a weather‐based forecasting model to estimate the WNV mosquito infection rate one to 3 weeks ahead of mosquito testing both statewide and for nine regions of Illinois. We further evaluated human illness risk relative to both the measured and the model‐estimated infection rates to provide guidelines for public health messages. We determined that across 10 years, over half of human WNV cases occurred following the 29 (of 210) weeks with the highest mosquito infection rates. The values forecasted by the models can identify those time periods, but model results and data availability varied by region with much stronger results obtained from regions with more mosquito data. The differences among the regions may be related to the amount of surveillance or may be due to diverse landscape characteristics across Illinois. We set the stage for better use of all surveillance options available for WNV and described an approach to modelling that can be expanded to other mosquito‐borne illnesses.     

Risk factors of Leptospira infection in Mediterranean periurban micromammals

Urbanization of natural areas can change abiotic factors, providing artificial sources of humidity in summer and decreasing variation of temperatures in winter. Our study aimed at document risk factors of infection in mammal reservoirs of pathogenic Leptospira in the human/wildlife interface of a large metropolitan area. We hypothesize that survival of Leptospira and thus their prevalence in animal reservoirs should be higher in residential areas than in natural habitats, especially after the hot, dry Mediterranean summers. We established the prevalence of Leptospira spp. and identified the serovars in 353 urine samples from micromammals (chiefly the wood mouse Apodemus sylvaticus, n = 266) using direct immunofluorescence and PCR. Animals were captured in spring and autumn, 2011–2012, in two natural parks and two adjacent residential areas in periurban Barcelona (NE Spain). Overall observed prevalence of infection was 11%, ranking between 8% and 13% in the better represented host species. We observed marked differences between seasons; the probability of finding a micromammal infected in spring was three times greater than in autumn (almost four times for wood mouse). Prevalence was not related with type of habitat, micromammal relative abundance or sex of the animal. Three Leptospira species were confirmed: Leptospira interrogans (47% of cases), Leptospira borgpetersenii (41%) and Leptospira kirschneri (12%). The serovars most commonly detected were those typically hosted by rodents, and serovars Ballum and Icterohemorrhagiae were the only ones found in autumn. People living in periurban Barcelona and those visiting the natural areas of the metropolitan area face hazard of infection with rodent‐borne Leptospira, especially during spring.     

2016——2018年我国部分猪群塞尼卡病毒回顾性监测

塞尼卡病毒(Senecavirus A,SVA)是最近新出现的可引起猪水泡样病变的单股小RNA病毒。为了解SVA的流行状况,采集对2016—2018年从我国辽宁等省份猪群的164份病料和2018年从我国福建等7省份35个屠宰场的458份组织混合样品和95份血清样品,用荧光实时定量RT-PCR方法进行SVA检测和分析。结果显示:在2016年的48份样品中,从3个省份检测出7份阳性样品,阳性率为14.6%。2017年的32份病料中,从5个省份检测出7份阳性样品,占比为21.9%;2018年的84份病料中,从3个省份检测出19份阳性样品,占比为22.6%。屠宰场组织样品中,从6个省份检出55份SVA阳性样品,阳性率为12.0%;血清样品中,从1个省份检出7份阳性样品,阳性率为7.4%。结果表明,我国猪群SVA感染年份至少可追溯到2016年;SVA在我国流行面相对较广,且猪群中存在隐性带毒,因此须重视猪群的SVA监视和监测。     

安徽省鸡常见病毒性肿瘤病的检测与调查

应用已建立的鸡肿瘤病快速鉴别诊断技术对源自安徽省5个不同地区的46个鸡群的肿瘤病、抑制病疑似病、死鸡305羽进行检测。结果表明,马立克氏病的阳性率为39．34%(120/305),禽网状内皮组织增生征阳性率为8．52%(26/305),禽白血病阳性率为2．624%(8/305)；另对17群未进行MD免疫的肉鸡进行随机抽样检测,其中5个鸡群检测出马立克氏病病毒强毒,阳性率为29．41%(5/17),阳性群的平均检出率为24 %。     

Evaluation of a competitive ELISA for antibody detection against avian influenza virus

Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity.     

Patterns of rabies occurrence in Bhutan between 1996 and 2009

This study was conducted to evaluate incidence and seasonal trends of rabies in dogs and other domestic animals in Bhutan from 1996 to 2009. Time series analysis approach was used to determine the seasonal trend and temporal association between species-specific rabies cases in animals. A total of 814 rabies cases were reported during the 14-year period, of which cattle and domestic dogs accounted for 55% (447/814) and 39% (317/814) of the cases, respectively. The remaining 6% of the cases (50/814) were reported in horses (2%), cats (2%), pigs (1%) and goats (1%). Rabies cases were reported throughout the year with more reports during spring and summer months. The annual patterns of cases were stable from 1996 to 2005, but the incidence increased during 2006 and 2008. Fifty-nine of the 205 sub-districts reported rabies in animals from 1996 to 2009 with increased incidences in the four districts in southern Bhutan, an area located close to the border towns of India. A significant (P < 0.05) positive cross-correlation was observed between the number of cases in dogs and other domestic animals at time lags (months) 1-3 with the highest correlation (r = 0.94, P < 0.05) observed at time lag 0 (same month) indicating that the peak in rabies incidences occur in the same month when both dogs and other domestic animal cases are reported. Regression analysis predicted rabies in other domestic animal when there are reports of rabies in dogs during the previous months. This study provides useful information about the epidemiology of rabies that can be used to plan a rabies control programme in Bhutan.     

丹麦有机猪的生产和养猪业沙门氏菌的控制

本文介绍了丹麦有机猪的生产情况(有机猪的品种、畜舍环境和条件、畜舍卫生和饲养饲料状况)、沙门氏菌控制计划的情况(饲料、种猪群、断奶仔猪群、育肥猪群和屠宰场的监控)和效果。同时,简析了我国发展有机畜牧业的必要性,最后提出实行危害分析和关键控制点(HACCP)预防管理体系和有机养殖是我国养猪业的发展方向。