gdri-ehede

Long term monitoring in south Gansu, China

Patrick Giraudoux — 2014-05-29T07:10:05Z

Twenty years after: pilot study in south Gansu, China, to monitor the transmission ecology of alveolar echinococcosis.

29th May 2014

Echinococcus multilocularis is a parasite that circulates between hosts that harbor the adult form, like fox and dog, and hosts who host the larval form, such as rodents and some species of lagomorphs. Absorption of parasite eggs, voided into the environment through fox and dog faeces leads to a severe disease, alveolar echinococcosis, which has been extensively studied in Franche-Comté. In the cantons of high endemicity, it can reach a prevalence of 1 ‰ in the human population.

In the late 80s, a focus of higher endemicity was discovered by Phil Craig (University of Salford , UK) and Liu Deshan ( Lanzhou Medical College) in Zhang and Min counties, south Gansu , western China. Multidisciplinary studies were carried out there from 1994 to 1997 as part of a European program initiated by Phil Craig (UK) and Dominique Vuitton (F), with Patrick Giraudoux (F) in charge of ecology studies. A 4.1% prevalence of alveolar echinococcosis was found in the human population, with peaks near 15% in some villages. It was also established that populations of foxes and dogs, abundant in the late 80s, had collapsed (only 1-2 dogs had been observed throughout the study). It was therefore likely that the human cases detected were infected before that time. It was also shown that the areas where the extension of shrub and grassland areas was larger, showed nearly 3 times higher prevalence than areas where ploughs dominated. From those observations, a transmission model was deducted which proved very general thereafter since applicable in Europe as well as in most parts of China and Central Asia.

Patrick Giraudoux, Phil Craig, Li Wenke and Nabil Pervaiz, with the support of the Lanzhou University (Prof. Jing Tao), went at their former study sites from May 20 to 24. Difficult to access, this altitude area (2200-2600 m) was the epicenter of an earthquake of magnitude 5.9-6.6, on the 22nd July 2013. The aim of the visit was to assess the feasibility of monitoring the situation 26 years after the discovery of the focus of alveolar echinococcosis and 20 years after the first multidisciplinary study was carried out there. A significant increase in the dog population was recorded (several hundred in every village), but the fox population, from local judgment, did not seem to have restored. A screening of the human population conducted in 2005-2006 by Prof. Shi Dazhong and Dr. Zhao Yumin (Lanzhou University) shows that at least one person could have become infected in the period that followed the extinction of dog populations. Subsequently, the situation is at high risk of re- intensifying the transmission of alveolar echinococcosis in the region. Subject to mobilize the necessary funds, a new expedition will be organized in 2015, with the following priorities:

to assess the intensity of infection and model its spatial distribution in dog populations (an important issue critical to prevent human infection)
to evaluate dog diet and re-assess the distribution of small mammal populations
to follow up human cases who were detected during screenings from 1994 - 1997 and 2005-2006 and whose almost half are still alive.

Such monitoring will uniquely contribute to the understanding of how Echinococcus multilocularis transmission varies on the long term (over almost 30 years) and the environmental and anthropogenic key factors driving these variations. Eventually, it will help to guide public health awareness, prevention and control.


Location of the study area

2015: Dog survey in Zhang and Min counties

23rd May 2015

A team including Patrick Giraudoux, Eve Afonso, Dominique Rieffel (University of Franche-Comté – CNRS, France), Jia WanZhong, Yan HongBin, Li ShuangNan, Zhang HaiLong (Lanzhou Veterinary Institute of the Chinese Academy of Agricultural Sciences, China) joined forces in Zhang and Min counties, from May 13 to 20, on the study site monitored since the late 80s. The aim was to assess the intensity of dog infection, if any, and model its spatial distribution. It was also to evaluate the route for dog infection by analyzing dog diet.

257 dog faeces have been collected in 26 villages between 2300 and 2700 m of altitude. They will be further processed using complementary methods (ELISA, PCR, qPCR, etc.) at the Chrono-environment department of the University of Franche-Comté and CNRS, at the Lanzhou Veterinary Research Institute and at the University of Salford (UK).

Furthermore, the natural coniferous vegetation of those mountains could be observed around the GuiQin shan (贵清山) temple. This forest area where leopard is believed to be still present makes a striking contrast with the agricultural landscape of field terraces and shrubland patches which cover the entire region at this altitude.

On May 22, a meeting in Lanzhou gathered people having participated to the field work, with Jing ZhiZhong (Lanzhou Veterinary Research Institute), Jing Tao (Lanzhou Medical College) , Yang Yurong and Xu YangYang (Ningxia Medical University), who travelled from Yinchuan especially for the meeting, and other colleagues from the Lanzhou Veterinary Research Institute and the Lanzhou Medical College. This strengthened the bases for further cooperation.

2019: Overarching article in PLoS

30th August of 2019

Published in the journal PLoS Neglected Tropical Diseases, a multi-disciplinary follow-up of more than 25 years, was conducted by researchers from the laboratory Chrono-environment, CHRU Jean-Minjoz (Besançon, France), Universities of Salford (UK) and Lanzhou, and the Lanzhou Veterinary Research Institute (China). It identifies the different stages an tipping points of the socio-ecological elimination of one of the most pathogenic parasitic zoonoses in the world: alveolar echinococcosis.

The main results and their context have been posted in the CNRS news (in French): "Élimination socio-écologique d'un parasite létal, l'échinocoque alvéolaire, dans le Gansu, Chine"

Contacts:
Patrick Giraudoux
Chrono-environment, University of Franche-Comté, France
Philip S. Craig
Cestode zoonoses group, Salford University, UK

Kyrgyzstan

2013-11-19T11:45:09Z

Large foci of transmission have been discovered in Western China since the 80's and in Central Asia (Kyrgyzstan, Kazakhstan, etc.) more recently. Human echinococcosis is increasing in Kyrgyzstan, with many new cases in the country's South. Little is known on the ecology of hosts and parasites in those areas. This programme is supported by the Wellcome Trust.


Location of the study area

2012, May 7-23 : first field work in the Alay valley, Pamir, Kyrgyzstan, and follow up

A multidisciplinary team travelled to the Alay valley including, Mike Rogan, Mark Danson, Alex Mastin, Freya van Kesteren (Salford University, UK), Iskender Ziadinov, Bermet Mytynova (Veterinary Institute, Bishkek, Kirghizstan), Paul Torgerson (University of Zurich, CH), Eve Afonso, Nicolas Tete and Patrick Giraudoux (Chrono-environment, University of Franche-Comté, F).

The Chrono-environment department's group investigated the interactions between landscape and small mammal intermediate host communities. Small mammal communities and land cover were sampled around Sary Moghol (3000 m alt), Alay valley, at the bottom of the Lenine Peak (7134m). The aim was to provide a first assessment of basic components of the transmission system in order to analyse possible landscape effects on population dynamics and transmission (see Giraudoux et al. 2013).

Based on previous reports of human echinococcosis in the Alay valley, four communities were selected by the University of Salford team for further investigation: Sary-Mogul, Taldu-Suu, Kara-Kabak and Kashka'Suu. Within these communities, approximately 700 households were visited and around 400 dogs were registered in May 2012. Faecal samples were collected from the majority of these dogs, in order to test for the presence of Echinococcus parasites. The World Bank has subsequently began a praziquantel dosing campaign in the area, and Freya van Kesteren and Alex Mastin have revisited a selection of households within the study villages at regular intervals (October 2012, April and September 2013, and April and September 2014) in order to sample dogs and monitor their infection status.

Freya has described the baseline prevalence of canine infection in these villages, and has also described the demographics, husbandry and roaming behaviour of these dogs. She has also assessed the levels of environmental contamination with dog faeces, which are a potential risk to humans, and conducted infection surveys in a number of nearby villages. Alex has developed novel methods of diagnostic test interpretation in order to estimate the burden of canine infection before and during the control scheme, has identified risk factors for canine infection, and has investigated people's attitudes towards dogs and zoonotic diseases. It is hoped that this data will be used to develop a mathematical model of Echinococcus spp. transmission in the Alay Valley, in order to better understand the epidemiology of this parasite in these communities and optimise ongoing surveillance and control efforts.

2014, August 19-31: complementary study on the wildlife compartment: small mammal survey and fox faeces collection

Patrick Giraudoux, Dominique Rieffel (Chrono-environnement), Iskender Ziadinov (Vetsuisse Faculty, University of Zurich) and Carole Bodin (CERFE) settled for 13 days in Sary Moghul and undertake a small mammal survey based on standard trapping and line transects on grid. 48 standard traplines (3600 trap.nights) were set up and 51 animals captured. 87 faeces, most of them attributed to fox, have been collected. Furthermore, the team drove to the bottom of Lenine Peak through the autumn/spring pastures to reach and visit the summer pastures and assess habitats and small mammal distribution there.

2014, November 25-26: Research Workshop: Echinococcosis in Kyrgyzstan and the Region, Bishkek

Read More...

Journal of Helminthology special issue

Contacts:
Phil S. Craig
Cestod Zoonoses Research group
University of Salford, UK
Patrick Giraudoux
Chrono-environnement, University of Franche-Comté, France

Ningxia

2013-11-19T11:44:40Z

Does environmental change drive the spatiotemporal transmission dynamics of Echinococcus spp. in Ningxia, China?

A large focus of human alveolar echinoccocosis has been discovered in the 90s in Xiji county and close surroundings, in the south of the Ningxia Hui Autonomous Region of China (NHAR). Our researches carried out in the early 2000 pieced together indications that this hotspot of more than 3300 km2 was the consequence of a landscape change in the 80s (see eg Pleydell et al. 2008). Massive deforestation may have created large habitats favourable to small mammal communities prone to reach large population densities, subsequently sustaining intensive transmission of Echinococcus multilocularis, the causative parasite agent of human alveolar echinococcosis.


Location of the study area

In the early 2000s, the absence of dog in the villages visited (indirectly poisoned by rodenticides during small mammal control), the virtual extinction of fox populations and the fact that landscape was now only shaped by field terraces and overgrazed pastures on hill tops, suggested that the parasite cycle could no longer maintain in Xiji. It was however predicted that the intermediate stages of the ecological successions caused by current intensive reforestation programmes may create favourable conditions for a re-emergence of the parasite and the disease.

A preliminary survey carried out by the Ningxia Medical University in the mid-2000s among the teen-ager populations showed that, concomitant with the increase of forest and grass cover, the sero-prevalence of the genus Echinococcus was currently increasing in the area. This may be due to an increase of E. granulosus circulation due to the disorganization/privatization of the former governmental abattoir system and/or to the re-emergence of E. multilocularis due to small mammal habitat changes.

The Australian National Health and Medical Research Council and the Ningxia Medical University, in collaboration with the University of Queensland, have launched a programme to monitor and understand what is currently happening there. In this framework, the Chrono-environnement department coordinates researches on the interactions between landscape and small mammal communities.

2012, July 2 to July 22: field work in Xiji and Guyuan counties

The main objectives were:

to evaluate the feasibility of simplified standard estimation of small mammal population relative densities (trapping success and index transects) on a larger extend (16500 km2) than earlier studies
to compare trapping and transects results (differences in population densities, etc.) obtained in 2012 to those of an earlier study achieved in Xiji and Guyuan in September 2003
to evaluate the feasibility of studying the evolution of small mammal habitats and landscape based on georeferenced photographs taken in September 2003 and July 2012.

First results indicate an important decrease of the populations of Spermophilus alashanicus between 2003 and 2012 and a probable increase of Eospalax (Myospalax) populations in the reforestation plots. They also show the numerical importance of Cricetulus longicaudatus in the small mammal community for the two periods considered. They corroborate the virtual absence of Arvicolid species in Xiji area (Arvicolids generally playing a key role in transmission elsewhere in Eurasia). This may have consequences on E. multilocularis transmission patterns. Options have been proposed to partners for further researches and surveillance.


Field work July 2012 report

2014, Angela Maria Cadavid Restrepo starts a PhD

July 4, 2015

Angela's PhD project has the following specific objectives:

To assess the seasonal and trend patterns in climate and land cover change in NHAR between 1980 and 2013.
To analyse associations between the spatiotemporal variation in human echinococcosis risk and the local patterns of climate change and landscape transformation at the township level in NHAR.
To examine the role of climate change and landscape transformation in the spatiotemporal variation in human echinococcosis risk across the villages in Xiji County.
To examine the role of climate change and landscape transformation in the spatiotemporal variation in human echinococcosis risk across the villages from selected Counties in South NHAR.

Contact:

Yang YuRong
Pathogen and Immunology Deparment
Ningxia Medical University, China

Tibetan plateau

2013-11-19T11:44:15Z

The Tibetan Plateau is one of the world's most important foci of human echinococcosis, and both cystic (泡型包虫病, pào xíng bāo chóng bìng) and alveolar (囊型包虫病, náng xíng bāo chóng bìng) echinococcosis occur.

Many members of the IRN EHEDE participated to research carried out there from 2001 to 2008 as part of the US National Institutes of Health (Fogarty Institute) programme "Ecology of infectious disease". Studies found that the canine echinococcosis (Em and Eg all together) rate exceeded 20% in some communities in Shiqu County on the Plateau.

Among them the contribution in ecology was to show that zoonotic transmission of the cestode E. multilocularis in China was not directly correlated with small mammal host species richness, but spatially correlated with alpine meadows, forest characteristics and rainfall that confirmed hotspots of human disease in a 200,000 km2 region of the eastern Tibetan plateau. Our findings indicate more intensive transmission in homogeneous landscapes with larger areas of optimal habitats for one or some host species in low diversity small mammal communities, making multi-annual population outbreaks more likely. Landscape features that could support large population outbreaks of small mammal host species were better predictors of E. multilocularis transmission to humans than indices of host species richness per se. Our results support the notion that landscape, small mammal host biodiversity and their population dynamics may protect humans from zoonotic parasite transmission where they prevent population outbreaks of a few specific small mammal host species. See e.g. Giraudoux et al. 2013. A new species of the genus Echinococcus, E. siqhicus, circulating through a Tibetan Fox/Plateau Pika cycle was also discovered (Xiao et al. 2005)


Location of the study area

Contacts:
Patrick Giraudoux
University of Franche-Comté, France

Phil S. Craig
University of Salford, UK

In 2005, the Chinese government implemented the National Echinococcosis Control Programme, which includes regular praziquantel dosing of domestic dogs, the main source of human infection. Together with colleagues at the Sichuan Centre for Disease Control in Chengdu, as part of a Wellcome trust grant, the Salford group hopes to evaluate canine echinococcosis on the Tibetan Plateau seven years after the start of the control programme. In November 2013, Dr. Yu Wenjie from the Sichuan CDC travelled to four communities on the Plateau (Yiniu, Mengsha, Xiazha and Arizha) and sampled 183 dogs in these communities. We aim to analyze these faecal samples for Echinococcus spp. and in doing so, evaluate the impact of the control programme on canine echinococcosis in these communities. Results in Wang et al. 2016

Contacts:
Wang Qian
Sichuan Institute of Parasitic Diseases
Sichuan CDC, China

Phil S. Craig
University of Salford, UK

2018: Back to Serxu, Sichuan

The Sichuan Center for Disease Control (CDC) and international partners such as the University of Franche-Comté, France, and the University of Salford, UK, have carried out a number of national and international research programmes in Serxu/ShiQu county, Sichuan, since the late 1990s (see above and Wang et al. 2004, Li et al 2005, Wang et al. 2006a, 2006b, etc.). Moreover, since 2005, a National Control Programme focuses on this high endemicity area where both cystic and alveolar echinococcoses still affect several thousands of people, most of them Tibetan herdsmen/women..

The Sichuan CDC group for cestode zoonoses has organized a pilot mission in Serxu, from June 18 to 24, to prepare the next field work scheduled in August. The study field is at 4200-4700 m of altitude close to the Qinghai province and the city of Yushu. The objective was to evaluate how camera traps, drone technologies and spatial methods might help to improve the monitoring of key transmission parameters in the area (dog and fox census, small mammal activity, behaviours, geolocation of patients, etc.).

Participants: Wang Qian 王谦 (head of the CDC group), Liao Sha 廖沙, Zhang GuangJia 张光葭, Yang Liu 杨柳, Wang Qi 王奇 and He Wei 何伟 (CDC staffs), Patrick Giraudoux (University of Franche-Comté & YUFE) invited as a consultant by the Sichuan CDC, in semi-permanent connexion with Christopher Marston (Edge Hill University) staying in UK as an adviser. The local CDC kindly provided logistical support on the spot.

Results:

we took 47 ground control points in order to extend former maps of the eastern part of the study area further west. Furthermore, we set up a common methodology to georeference villages, hamlets, summer pasture camps, based on local documents, satellite and aerial imagery. This should allow the study of the spatial distribution of patients at finer grain and the possible impact of their environment to parasite transmission.

we carried out trials to calibrate altitude and trajectories of a drone, in order to survey dog and small mammal indices e.g. (pika holes, etc.) spatial distribution.

we set up camera traps in order to monitor dog and small mammal behaviour and their possible interactions with humans.

Perspectives: a stronger team including mammologists of the Sichuan Normal University, equipped with an additional drone and infra-red camera is going to come back in August for a full-size study. Moreover, this year, Pr. Wang Qian has submitted a research proposal to the National Natural Science Foundation of China, aiming at understanding the mechanisms of parasite transmission patterns in small mammals in the course of the National Control Programme. This application includes consultancy from several members of the Chrono-environment lab, University of Franche-Comté, and one from Edge Hill University, all members of the GDRI EHEDE.

2018: Meeting November 5-6 in Chengdu, Sichuan CDC.

The aim was to concert about data analysis and GIS issues related to the pilot study carried out in June and the full size field research achieved in August when 360 AE/CE patients were identified in Eduoma area. Exchanges focused on photo-interpretation of imagery obtained by drone, and on harmonization of geographical coordinate systems used for data storage and analysis. Additionally specific R scripts were developed for preliminary analysis of patient data in a spatial context.

Participants: Wang Qian 王谦 (head of the CDC group), Liao Sha 廖沙, Zhang GuangJia 张光葭, Yang Liu 杨柳, Wang Qi 王奇, He Wei 何伟, Chen Fang 陈凡 (CDC staffs), Patrick Giraudoux (University of Franche-Comté & YUFE). The group was kindly introduced by Pr. Zhong Bo 钟波 head of the Institute of Parasitic Disease of the Sichuan CDC.

Contact:
Wang Qian
Sichuan Institute of Parasitic Diseases
Sichuan CDC, China

2019: Review about Echinococcosis transmission on the Tibetan Plateau

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