Monitoring and Intervention Strategies for Bluetongue Virus Epidemics in Rural India

印度农村地区蓝舌病毒流行的监测和干预策略

• 批准号: BB/H009205/1
• 负责人: Simon Carpenter
• 金额: $ 62.15万
• 依托单位: The Pirbright Institute
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FH009205%2F1
• 关键词: Monitoring; Intervention; Strategies; Bluetongue; Virus

Bluetongue virus (BTV) is an arboviral pathogen of ruminants spread by Culicoides biting midges, which causes the disease bluetongue (BT) in sheep (particularly certain fine wool and mutton breeds). During the 1980's clinical BT began to appear in flocks of native Indian breeds of sheep, particularly in the southern states, possibly as a result of exotic strains of the virus introduced via sheep-breeding programmes. This change in epidemiology led to outbreaks among family-based subsistence farming communities in these areas, and BTV has since been become a significant constraint in both the rearing and productivity of indigenous flocks. In addition, in rain-fed agricultural areas, massive periodic outbreaks of disease occur that are thought to be related to the influence of timing and intensity of monsoon conditions on populations of vectors responsible for spreading BTV. Due to the circulation of 21 serotypes of BTV in southern India and the prohibitive costs of vaccination to the vast majority of the population, vector control remains the only feasible way of combating BTV transmission in the field. Despite this, virtually no quantitative data concerning the efficiency of available techniques in this role is available to inform control strategies. We will adopt a multidisciplinary approach involving mathematical modelling, entomology and chemical ecology to examine the epidemiology of BTV in the southern Indian states and to produce prediction, monitoring and mitigation techniques that can reduce the impact of BT in this region. Initially we will characterise southern India using mapping techniques that delineate land areas according to climate and land use patterns. We will then establish field sites across the region that are representative of both these factors and also the types of husbandry employed (with an emphasis on small holdings and landless husbandry workers). Having characterised these sites, we will then use light trapping to define adult seasonality and distribution and ground truth this survey with direct collection of Culicoides from livestock. These studies will be combined with detection of BTV within collected individual midges to define regional variation in which species are involved in transmission in southern India for the first time. The larval development sites of major vector species identified will then also be characterised via field investigations. Using data generated on adult seasonality, larval habitat preference and historic surveys of BT cases across southern India, we will then model the relationship between monsoon conditions and adult Culicoides/BT activity to assess the potential to produce an early warning system for major BTV epidemics based on meteorological variables. The provision of fundamental epidemiological knowledge will also enable an assessment of husbandry-based control techniques for Culicoides that could be employed to reduce BTV transmission by subsistence farmers in a cost-neutral fashion. We will examine traditional and novel means of control, both in the laboratory and in the field. The former will include the use of larval site modification, or targeted treatment with traditional, low environmental impact, insecticidal products available to villagers and additionally the use of stabling. In addition, information regarding host location by identified vector Culicoides will allow novel intervention strategies based upon the application of masking semiochemicals that could also reduce the use of synthetic insecticides by these communities in the medium term. The effect of combinations of these techniques will be examined via monitoring viral infection in livestock, as a gold standard for evidence of impact in the field. These data will then be assessed for integration into the everyday lives of user groups as part of wider dissemination frameworks for improvement of ruminant productivity and control of vectors of human and veterinary pathogens.

蓝舌病毒(Bluetongue Virus，BTV)是一种由库蚊叮咬蚊虫传播的反刍动物的虫媒病毒，可引起绵羊(特别是某些细毛羊和羊肉品种)蓝舌病(Bt)。在20世纪80年代，S临床Bt开始出现在印度本土品种的羊群中，特别是在南部各州，可能是由于通过绵羊育种计划引入的外来病毒株的结果。流行病学的这种变化导致了这些地区以家庭为基础的自给自足农业社区的暴发，自那以来，BTV已成为土著畜群饲养和生产力的重大制约因素。此外，在雨养农业地区，疾病的大规模周期性暴发被认为与季风条件的时间和强度对负责传播BTV的媒介种群的影响有关。由于21种BTV血清型在印度南部的传播，以及对绝大多数人口接种疫苗的高昂费用，病媒控制仍然是现场抗击BTV传播的唯一可行方法。尽管如此，几乎没有关于这一角色中可用技术效率的量化数据来为控制策略提供信息。我们将采用涉及数学模型、昆虫学和化学生态学的多学科方法来研究BTV在印度南部各州的流行病学，并制定预测、监测和缓解技术，以减少Bt对该地区的影响。首先，我们将根据气候和土地利用模式，使用地图绘制技术来描绘印度南部的土地面积。然后，我们将在整个区域建立既能代表这些因素，又能代表所雇用的畜牧业类型(重点是小农场和无地畜牧业工人)的实地地点。在确定了这些地点的特征后，我们将使用灯光诱捕法来确定成虫的季节性和分布，并通过直接从家畜中收集库蚊来证明这项调查的真相。这些研究将与在收集的个体蚊子中检测BTV相结合，以确定哪些物种首次参与印度南部传播的区域变异。然后，还将通过实地调查确定主要媒介物种的幼虫发育地点。利用印度南部成虫季节性、幼虫栖息地偏好和Bt病例历史调查产生的数据，我们将模拟季风条件和成虫库蚊/Bt活动之间的关系，以评估基于气象变量建立重大BTV疫情预警系统的可能性。提供基本的流行病学知识还将有助于评估以畜牧业为基础的库蚊控制技术，这些技术可用于以成本中立的方式减少自给自足农民的BTV传播。我们将在实验室和现场检查传统和新的控制手段。前者将包括使用幼虫地点改良，或使用传统的、对环境影响低的有针对性的治疗，村民可获得杀虫产品，此外还使用马厩。此外，已确定的媒介库蚊寄主位置的信息将使基于应用掩蔽信号化学物质的新干预策略成为可能，这些策略也可能在中期内减少这些社区使用合成杀虫剂。将通过监测牲畜中的病毒感染来检验这些技术组合的效果，作为实地影响证据的黄金标准。然后将对这些数据进行评估，将其纳入用户群体的日常生活，作为提高反刍动物生产力和控制人类和兽医病原体媒介的更广泛传播框架的一部分。

项目成果

Insecticidal effects of deltamethrin in laboratory and field populations of Culicoides species: how effective are host-contact reduction methods in India?

• DOI: 10.1186/s13071-017-1992-0
• 发表时间: 2017-01-31
• 期刊: Parasites & vectors
• 影响因子: 3.2
• 作者: De Keyser R;Cassidy C;Laban S;Gopal P;Pickett JA;Reddy YK;Prasad M;Prasad G;Chirukandoth S;Senthilven K;Carpenter S;Logan JG
• 通讯作者: Logan JG

Additional file 1: Table S1. of DNA barcoding and surveillance sampling strategies for Culicoides biting midges (Diptera: Ceratopogonidae) in southern India

附加文件 1：表 S1。

• DOI: 10.6084/m9.figshare.c.3616160_d2
• 发表时间: 2016
• 作者: Harrup L

DNA barcoding and surveillance sampling strategies for Culicoides biting midges (Diptera: Ceratopogonidae) in southern India.

• DOI: 10.1186/s13071-016-1722-z
• 发表时间: 2016-08-22
• 期刊: Parasites & vectors
• 影响因子: 3.2
• 作者: Harrup LE;Laban S;Purse BV;Reddy YK;Reddy YN;Byregowda SM;Kumar N;Purushotham KM;Kowalli S;Prasad M;Prasad G;Bettis AA;De Keyser R;Logan J;Garros C;Gopurenko D;Bellis G;Labuschagne K;Mathieu B;Carpenter S
• 通讯作者: Carpenter S