The black rat(Rattus rattus)poses a severe threat to food security and public health in Madagascar,where it is a major cause of pre-and post-harvest crop losses and an important reservoir for many zoonotic diseases,in...The black rat(Rattus rattus)poses a severe threat to food security and public health in Madagascar,where it is a major cause of pre-and post-harvest crop losses and an important reservoir for many zoonotic diseases,including plague.Elsewhere,ecologically based rodent management(EBRM)strategies have been developed using ecologi-cal information to inform decisions on where and when to target control.EBRM could deliver improved health and well-being outcomes in Madagascar if adapted to the local ecological context.Using data collected from removal studies,we explored spatio-temporal patterns in the breeding activity of the black rat(R.rattus)in domestic and agricultural habitats across Madagascar and investigated to what extent these trends are influenced by rainfall and rat density.We identified clear spatio-temporal variation in the seasonality of R.rattus reproduction.Reproduction was highly seasonal both inside and outside of houses,but seasonal trends varied between these two habitats.Sea-sonal trends were explained,in part,by variation in rainfall;however,the effect of rainfall on reproductive rates did itself vary by season and habitat type.A decline in breeding intensity with increasing rat density was recorded outside of houses.This has important implications for control,as populations may compensate for removal through increased reproduction.We recommend that sustained control initiated before the main breeding season,combined with improved hygiene and adequate rodent-proofing in homes and grain stores,could curtail population growth and reduce pre-and post-harvest losses provided that these measures overcome the compensatory response of rodent populations.展开更多
The epidemiology of Yersinia pestis,the causative agent of plague,involves vectors and reservoirs in its transmission cycle.The passive plague surveillance in Madagascar targets mainly rodent and fleas.However,carnivo...The epidemiology of Yersinia pestis,the causative agent of plague,involves vectors and reservoirs in its transmission cycle.The passive plague surveillance in Madagascar targets mainly rodent and fleas.However,carnivores are routinely surveyed as sentinels of local plague activity in some countries.The aim of this study is to assess the use of domestic dog(Canis familiaris)as sentinel animal for field surveillance of plague in a highly endemic area in Madagascar.Cross-sectional surveys of plague antibody prevalence in C.familiaris were conducted in endemic areas with contrasting histories of plague cases in humans,as well as a plague free area.Rodent capture was done in parallel to evaluate evidence for Y.pestis circulation in the primary reservoirs.In 2 sites,dogs were later re-sampled to examine evidence of seroconversion and antibody persistence.Biological samplings were performed between March 2008 and February 2009.Plague antibody detection was assessed using anti-F1 ELISA.Our study showed a significant difference in dog prevalence rates between plague-endemic and plague-free areas,with no seropositive dogs detected in the plague free area.No correlation was found between rodents and dog prevalence rates,with an absence of seropositive rodents in some area where plague circulation was indicated by seropositive dogs.This is consistent with high mortality rates in rodents following infection.Re-sampling dogs identified individuals seropositive on both occasions,indicating high rates of re-exposure and/or persistence of plague antibodies for at least 9 months.Seroconversion or seropositive juvenile dogs indicated recent local plague circulation.In Madagascar,dog surveillance for plague antibody could be useful to identify plague circulation in new areas or quiescent areas within endemic zones.Within active endemic areas,monitoring of dog populations for seroconversion(negative to positive)or seropositive juvenile dogs could be useful for identifying areas at greatest risk of human outbreaks.展开更多
Rodents represent a serious threat to food security and public health.The extent to which rodent control can mitigate the risk from rodent-borne disease depends on both the effectiveness of control in reducing rodent ...Rodents represent a serious threat to food security and public health.The extent to which rodent control can mitigate the risk from rodent-borne disease depends on both the effectiveness of control in reducing rodent abundance and the impact on disease epidemiology.Focusing on a plague-endemic region of Madagascar,this study compared the effectiveness of 3 methods:live-traps,snap-traps,and rodenticides.Control interventions were implemented inside houses between May and October 2019.Tracking tiles monitored rodent abundance.Rodent fleas,the vector involved in plague transmission,were collected.Rodent populations consisted of Rattus rattus and Mus musculus.In terms of trap success,we found that our live-trap regime was more effective than snap-traps.While all 3 control strategies appeared to reduce in-house rodent activity in the short term,we found no evidence of a longer-term effect,with in-house rodent abundance in treated sites comparable to non-treatment sites by the following month.Endemic flea,Synopsyllus fonquerniei,is a key plague vector usually found on rats living outdoors.Although we found no evidence that its abundance inside houses increased following control,this may have been due to a lack of power caused by significant variation in S.fonquerniei abundance.The presence of S.fonquerniei in houses was more likely when S.fonquerniei abundance on outdoor rats was higher,which in turn correlated with high rat abundance.Our results emphasize that control strategies need to consider this connectivity between in-house rat–flea populations and the outdoor populations,and any potential consequences for plague transmission.展开更多
Background:Prisons in Madagascar are at high risk of plague outbreak.Occurrence of plague epidemic in prisons can cause significant episode of urban plague through the movement of potentially infected humans,rodents a...Background:Prisons in Madagascar are at high risk of plague outbreak.Occurrence of plague epidemic in prisons can cause significant episode of urban plague through the movement of potentially infected humans,rodents and fleas.Rodent and flea controls are essential in plague prevention,by reducing human contact with plague reservoirs and vectors.Insecticide treatment is the key step available for the control of rat fleas which transmit the disease from infected rodents to human.The implementation of an adapted flea control strategy should rely on the insecticide susceptibility status of the targeted population.For the purpose of plague prevention campaign in prisons,we conducted insecticide resistance survey on Xenopsylla cheopis,the rat flea.Methods:Fleas were collected on rats caught in six prisons of Madagascar.They were exposed to insecticide treated filter papers and mortality was recorded following World Health Organization protocol.Results:The fleas collected in the prisons had different resistance patterns,while a high level of resistance to insecticides tested was described in the Antanimora prison,located in the heart of Antananarivo,the capital of Madagascar.Conclusions:This finding is alarming in the context of public health,knowing that the effectiveness of flea control could be jeopardized by insecticide resistance.In order to establish more accurate rat fleas control in prisons,the main recommendations are based on continuous monitoring insecticide susceptibility of flea,insecticide rotation,and the development of a new method for flea control.展开更多
Plague has been known since ancient times as a re-emerging infectious disease,causing considerable socioeconomic burden in regional hotspots.To better understand the epidemiological cycle of the causative agent of the...Plague has been known since ancient times as a re-emerging infectious disease,causing considerable socioeconomic burden in regional hotspots.To better understand the epidemiological cycle of the causative agent of the plague,its potential occurrence,and possible future dispersion,one must carefully consider the taxonomy,distribution,and ecological requirements of reservoir-species in relation either to natural or human-driven changes(e.g.climate change or urbanization).In recent years,the depth of knowledge on species taxonomy and species composition in different landscapes has undergone a dramatic expansion,driven by modern taxonomic methods such as synthetic surveys that take into consideration morphology,genetics,and the ecological setting of captured animals to establish their species identities.Here,we consider the recent taxonomic changes of the rodent species in known plague reservoirs and detail their distribution across the world,with a particular focus on those rodents considered to be keystone host species.A complete checklist of all known plague-infectable vertebrates living in plague foci is provided as a Supporting Information table.展开更多
基金This work was also supported by the Wellcome Trust[095171/Z/10/Z]the Medical Research Council[MR/T029862/1]by the National Institute for Health Research(NIHR)(using the UK’s Official Development Assistance[ODA]Fund-ing)and Wellcome[219532/Z/19/Z]under the NIHR-Wellcome Partnership for Global Health Research.
文摘The black rat(Rattus rattus)poses a severe threat to food security and public health in Madagascar,where it is a major cause of pre-and post-harvest crop losses and an important reservoir for many zoonotic diseases,including plague.Elsewhere,ecologically based rodent management(EBRM)strategies have been developed using ecologi-cal information to inform decisions on where and when to target control.EBRM could deliver improved health and well-being outcomes in Madagascar if adapted to the local ecological context.Using data collected from removal studies,we explored spatio-temporal patterns in the breeding activity of the black rat(R.rattus)in domestic and agricultural habitats across Madagascar and investigated to what extent these trends are influenced by rainfall and rat density.We identified clear spatio-temporal variation in the seasonality of R.rattus reproduction.Reproduction was highly seasonal both inside and outside of houses,but seasonal trends varied between these two habitats.Sea-sonal trends were explained,in part,by variation in rainfall;however,the effect of rainfall on reproductive rates did itself vary by season and habitat type.A decline in breeding intensity with increasing rat density was recorded outside of houses.This has important implications for control,as populations may compensate for removal through increased reproduction.We recommend that sustained control initiated before the main breeding season,combined with improved hygiene and adequate rodent-proofing in homes and grain stores,could curtail population growth and reduce pre-and post-harvest losses provided that these measures overcome the compensatory response of rodent populations.
基金This work was funded by an internal research grant(Ref:PA 14.25)from the Institut Pasteur de MadagascarThis research was also funded in part by the Wellcome Trust[095171/Z/10/Z].
文摘The epidemiology of Yersinia pestis,the causative agent of plague,involves vectors and reservoirs in its transmission cycle.The passive plague surveillance in Madagascar targets mainly rodent and fleas.However,carnivores are routinely surveyed as sentinels of local plague activity in some countries.The aim of this study is to assess the use of domestic dog(Canis familiaris)as sentinel animal for field surveillance of plague in a highly endemic area in Madagascar.Cross-sectional surveys of plague antibody prevalence in C.familiaris were conducted in endemic areas with contrasting histories of plague cases in humans,as well as a plague free area.Rodent capture was done in parallel to evaluate evidence for Y.pestis circulation in the primary reservoirs.In 2 sites,dogs were later re-sampled to examine evidence of seroconversion and antibody persistence.Biological samplings were performed between March 2008 and February 2009.Plague antibody detection was assessed using anti-F1 ELISA.Our study showed a significant difference in dog prevalence rates between plague-endemic and plague-free areas,with no seropositive dogs detected in the plague free area.No correlation was found between rodents and dog prevalence rates,with an absence of seropositive rodents in some area where plague circulation was indicated by seropositive dogs.This is consistent with high mortality rates in rodents following infection.Re-sampling dogs identified individuals seropositive on both occasions,indicating high rates of re-exposure and/or persistence of plague antibodies for at least 9 months.Seroconversion or seropositive juvenile dogs indicated recent local plague circulation.In Madagascar,dog surveillance for plague antibody could be useful to identify plague circulation in new areas or quiescent areas within endemic zones.Within active endemic areas,monitoring of dog populations for seroconversion(negative to positive)or seropositive juvenile dogs could be useful for identifying areas at greatest risk of human outbreaks.
基金This work was supported by a Directorate General for International Relations and Strategy grant(2018-SB-024-18SSEOC049-PMG7-SSA5-IPMMADAGASCAR)covering the project“Développement de contre-mesures médicalesàla pesteàMadagascar”with scientific support of IRBA(French Armed Forces Biomedical Research Institute),within the framework of French MoD’s involvement in G7 Global partnershipThis research was also funded in part by the Wellcome Trust[095171/Z/10/Z]and the Institut Pasteur de Madagascar.For the purpose of Open Access,the authors have applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submissionK.S.was supported by the Biotechnology and Biological Sciences Research Council(BBSRC)under the EastBio DTP(grant number BB/M010996/1).
文摘Rodents represent a serious threat to food security and public health.The extent to which rodent control can mitigate the risk from rodent-borne disease depends on both the effectiveness of control in reducing rodent abundance and the impact on disease epidemiology.Focusing on a plague-endemic region of Madagascar,this study compared the effectiveness of 3 methods:live-traps,snap-traps,and rodenticides.Control interventions were implemented inside houses between May and October 2019.Tracking tiles monitored rodent abundance.Rodent fleas,the vector involved in plague transmission,were collected.Rodent populations consisted of Rattus rattus and Mus musculus.In terms of trap success,we found that our live-trap regime was more effective than snap-traps.While all 3 control strategies appeared to reduce in-house rodent activity in the short term,we found no evidence of a longer-term effect,with in-house rodent abundance in treated sites comparable to non-treatment sites by the following month.Endemic flea,Synopsyllus fonquerniei,is a key plague vector usually found on rats living outdoors.Although we found no evidence that its abundance inside houses increased following control,this may have been due to a lack of power caused by significant variation in S.fonquerniei abundance.The presence of S.fonquerniei in houses was more likely when S.fonquerniei abundance on outdoor rats was higher,which in turn correlated with high rat abundance.Our results emphasize that control strategies need to consider this connectivity between in-house rat–flea populations and the outdoor populations,and any potential consequences for plague transmission.
基金The fleas tested here were collected during rodent control campaign funded by the Swiss Embassy-Antananarivo(Ref#771.22.00-1-MAE/RML)Laboratory works were funded by Institut Pasteur de Madagascar.
文摘Background:Prisons in Madagascar are at high risk of plague outbreak.Occurrence of plague epidemic in prisons can cause significant episode of urban plague through the movement of potentially infected humans,rodents and fleas.Rodent and flea controls are essential in plague prevention,by reducing human contact with plague reservoirs and vectors.Insecticide treatment is the key step available for the control of rat fleas which transmit the disease from infected rodents to human.The implementation of an adapted flea control strategy should rely on the insecticide susceptibility status of the targeted population.For the purpose of plague prevention campaign in prisons,we conducted insecticide resistance survey on Xenopsylla cheopis,the rat flea.Methods:Fleas were collected on rats caught in six prisons of Madagascar.They were exposed to insecticide treated filter papers and mortality was recorded following World Health Organization protocol.Results:The fleas collected in the prisons had different resistance patterns,while a high level of resistance to insecticides tested was described in the Antanimora prison,located in the heart of Antananarivo,the capital of Madagascar.Conclusions:This finding is alarming in the context of public health,knowing that the effectiveness of flea control could be jeopardized by insecticide resistance.In order to establish more accurate rat fleas control in prisons,the main recommendations are based on continuous monitoring insecticide susceptibility of flea,insecticide rotation,and the development of a new method for flea control.
基金The study received funding support from the Pasteur Institute of Iran and Center for Disease Control of the Iranian Ministry of Health and Medical Education(grant no.810)the Slovenian Research Agency(research core funding no.P1-0255 to B.K.).
文摘Plague has been known since ancient times as a re-emerging infectious disease,causing considerable socioeconomic burden in regional hotspots.To better understand the epidemiological cycle of the causative agent of the plague,its potential occurrence,and possible future dispersion,one must carefully consider the taxonomy,distribution,and ecological requirements of reservoir-species in relation either to natural or human-driven changes(e.g.climate change or urbanization).In recent years,the depth of knowledge on species taxonomy and species composition in different landscapes has undergone a dramatic expansion,driven by modern taxonomic methods such as synthetic surveys that take into consideration morphology,genetics,and the ecological setting of captured animals to establish their species identities.Here,we consider the recent taxonomic changes of the rodent species in known plague reservoirs and detail their distribution across the world,with a particular focus on those rodents considered to be keystone host species.A complete checklist of all known plague-infectable vertebrates living in plague foci is provided as a Supporting Information table.
