(11.5)--小儿传染病学Sánchez-Soriano-2019-Development.pdf

RESEARCH ARTICLEOpen AccessDevelopment of a high number,highcoverage dog rabies vaccinationprogramme in Sri LankaCarlos Snchez-Soriano1*,Andrew D.Gibson2,3,Luke Gamble3,Jordana L.Burdon Bailey3,Samantha Green4,Mark Green4,Barend M.deC.Bronsvoort2,1,Ian G.Handel2,1,Richard J.Mellanby1and Stella Mazeri2,1AbstractBackground:Rabies is estimated to cause 59,000 deaths and economic losses of US$8.6 billion every year.Despiteseveral years of rabies surveillance and awareness programmes,increased availability of post-exposure prophylaxisvaccinations and dog population control,the disease still remains prevalent in Sri Lanka.This study reports the roll-out of a high number,high coverage canine rabies vaccination campaign in Sri Lanka,providing estimates for thevaccination coverage achieved,analysing the local dog demographics,and identifying barriers of attendance tostatic vaccination clinics.Methods:A mass dog vaccination campaign was undertaken in Negombo,Sri Lanka.The campaign wascomposed of static point and door-to-door vaccination stages,with a final survey of vaccination coverage.A largevolume of data on the distribution,health,and signalment of vaccinated dogs was collected through a mobilephone application.A logistic regression model was developed to investigate which socio-spatial and dog-relatedfactors influenced attendance of owners to static vaccination points.Results:The campaign vaccinated over 7800 dogs achieving a vaccination coverage of 75.8%.A dog:human ratioof 1:17 was estimated.Most dogs were owned,and the dog population was mostly male,adult,and non-sterilized.Unawareness,unavailability and handling problems were the most common reasons given by owners to explainfailure to attend a static vaccination point.The regression analysis showed that increasing distance to a static point,in addition to young age and poor health of the dog,were associated with a decrease in the likelihood ofattendance to a static vaccination points.Conclusion:This study demonstrates the feasibility of high number,high coverage vaccination campaigns in SriLanka.The information on dog ecology and barriers of attendance to static point vaccination clinics will facilitatedevelopment of future vaccination campaigns.Keywords:Rabies,Dogs,Sri Lanka,Vaccination,Mobile phone application,CoverageBackgroundRabies is still a prevalent and underreported disease inmany developing countries,causing 59,000 deaths eachyear,and economic losses amounting to 8.6 billion USDannually 1.Ninety-nine percent of human rabies casescan be traced back to bites from rabies infected dogs 2.Infected patients develop fatal encephalitis unless theyare treated shortly after the bite with post-exposureprophylaxis(PEP),a treatment not widely available inmany rabies-endemic regions 3,4.Since dog bites arethe main source of human infections 2,mass dog vac-cination campaigns represent the most effective courseof action to reduce rabies incidence 1,5,and have beenshown to reduce human infection rates in multiplesettings 68.The World Health Organization recom-mends a minimum annual vaccination coverage of 70%of the dog population 9,10 in order to achieve herdimmunity,reduce rabies incidence,and minimize the The Author(s).2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License(http:/creativecommons.org/licenses/by/4.0/),which permits unrestricted use,distribution,andreproduction in any medium,provided you give appropriate credit to the original author(s)and the source,provide a link tothe Creative Commons license,and indicate if changes were made.The Creative Commons Public Domain Dedication waiver(http:/creativecommons.org/publicdomain/zero/1.0/)applies to the data made available in this article,unless otherwise stated.*Correspondence:C.Sanchez-Sorianoed.ac.uk1The Royal(Dick)School of Veterinary Studies,The University of Edinburgh,Easter Bush Veterinary Centre,Roslin,Midlothian EH25 9RG,UKFull list of author information is available at the end of the articleSnchez-Soriano et al.BMC Infectious Diseases (2019)19:977 https:/doi.org/10.1186/s12879-019-4585-zburden of the disease in both dog and human popula-tions 5.In order to achieve this goal,different dog vaccinationstrategies are used depending on the local dog ecology,dog ownership structure,and the resources available.Static point(SP)vaccination approaches are commonlyused,as they are easy to establish and are an efficient wayto vaccinate a large number of dogs with limitedpersonnel.However,reliance on SP clinics only oftenleads to a failure to vaccinate a sufficient proportion of thepopulation,since they depend on high ownership levelsand other socio-economic and cultural factors which mayinfluence dog owners attendance 11.Although morelogistically challenging and costly,“door-to-door”(D2D)approaches based on visiting all households in a commu-nity and vaccinating free-roaming and owned dogs areable to achieve high coverages very effectively 12,13.Forthis reason,many vaccination campaigns combine SP andD2D stages to maximise vaccination coverage in a feasibleand cost-effective manner 14,15.Rabies-related human deaths in Sri Lanka have steadilydiminished since the establishment of the rabies controlprogram in 1975.Despite more than 30 years of efforts,the disease still represents a serious concern for theisland,especially in regions with economies largely sus-tained by tourism.The latest surveys in 2014 estimateda dog vaccination coverage of 48%16,which is consid-ered to be too low to rapidly eliminate the disease.Rabies remains prevalent among the Sri Lankan caninepopulation,resulting in around thirty human deathseach year 16.Consequently,PEP expenditure representsan important economic burden,amounting to more than300,000 prescriptions annually 16,17.Nationwide effortsto reduce the prevalence of the disease continue to bebased on treatment availability,dog vaccination,and straydog population control 1618.However,dog vaccinationand neutering methods in Sri Lanka have been poorly re-ported,with scarce data available on dog demographicsand vaccination coverage.The lack of a working templatefor high numbers,high coverage campaigns is one of thefactors hindering the development of efficient vaccinationoperations that could be applied in many of regions ofSri Lanka to enable the nation to reach sufficient dogvaccination coverage.This report describes a mass dogvaccination campaign carried out in Negombo by Mis-sion Rabies 19 and the Dogstar Foundation 20,which was able to vaccinate a large number of dogs,obtaining a high vaccination coverage,and whose de-sign could be implemented in other regions of thecountry to reduce the incidence of rabies.The objec-tives of this study included:the estimation of thevaccination coverage achieved,the analysis of thedemographics of the local dog population,and theidentification of barriers of attendance to SP.MethodsStudy areaNegombo is the biggest city in the Gampaha District,lo-cated in the western coast of Sri Lanka.Negombo alsoconstitutes one of the biggest hubs of the country,witha population of 142,136 inhabitants 21.Mission rabies 2016 vaccination campaign:period andcourse of the campaignA pilot D2D campaign in 2015 was used to demonstratethe feasibility and effectiveness of working protocols.The 2016 campaign was performed between June andSeptember,and covered most of the city,whose areawas divided into 33 wards(Fig.1),denominated withnumbers 1 to 34 and missing number 21.Based on pre-vious information regarding ownership levels from the2015 pilot campaign 19 and reports from anothermunicipality in Gampaha District 22,a SP stage wasincluded in the campaign.A total of 146 static vaccin-ation points were set up daily in different areas of thecity(Fig.1),from June 15th to September 1st,givingcoloured collars to the animals administered vaccination(Nobivac Rabies,MSD Animal Health).The SP effortswere complemented by a D2D stage,from September12th to 28th,in which the staff members covered the en-tire area of each working zone,vaccinating and marking(with paint and/or a collar)any dogs found on the streetand knocking on household doors to offer vaccination toowned dogs.Free-roaming dogs which did not approachtheteamswillinglywerecaughtusinglightweightBalinese-style nets,and restrained securely.All staffmembers involved in the vaccination process weretrained to do so causing the minimum distress to the an-imals.A survey to assess the vaccination coverage wasperformed from September 13th to 29th,recording thepresence or absence of paint marks and collars on anydogs seen while travelling on every traversable road ofeach ward using a tuk tuk.Surveys were usually carriedthe day after the D2D vaccination,otherwise surveyswere carried out maximum 2 days after.In 2 wardswhere the coverage results were below 70%,the vaccin-ation teams were sent for a second round of D2Dvaccination and subsequent survey.Survey entries gath-ered in wards 13,24,25,26,27,28,29,30 and 34 werecollected by a different surveyor,since the original sur-veying supervisor was not available.Due to the lack oftraining,entries from these 9 wards were not included inthe coverage assessment.Field data during all stages wascollected using the Mission Rabies App 23,a web-based platform created for simple management andstreamlined entry of field data.The app collected globalpositioning system(GPS)coordinates and timestampsfor each dog vaccinated automatically and offered apath-tracking tool allowing the staff to check theirSnchez-Soriano et al.BMC Infectious Diseases (2019)19:977 Page 2 of 12spatial coverage in real time.The app also requestedadditional relevant data of the dog such as sex,age,health status or neuter status in addition to otherinformation such as the team responsible for the vaccin-ation,the provider of any previous vaccine,and theopinionofownersonmatterssuchasneuteringFig.1 Topographical division of Negombo in 33 wards.The division into wards was performed according to the working zone shapefileprovided by Mission Rabies.The location of the 146 static vaccination points is marked as dots.The location of Negombo within Sri Lanka isshown on the right.Background map tiles by Stamen Design,under CC BY 3.0.Data by OpenStreetMap,under ODbLSnchez-Soriano et al.BMC Infectious Diseases (2019)19:977 Page 3 of 12procedures and the reason why they did not bring theirdog to a SP.Data sourcesCollection tools and data collectedField data collected using the Mission Rabies App 23was compiled into datasets and used for this study.Ashapefile containing the specifics of the polygons usedby Mission Rabies to divide Negombo in the 33 wardswas also provided.Other sourcesData regarding additional geospatial variables for the re-gression analysis was obtained from publicly availablesources.Weather data for Negombo during the cam-paign was obtained from the World Weather Onlinedatabase 24,averaging the tri-hourly measurements fortemperature and precipitation during the working hours(6:0015:00)for each day of the SP campaign.A rasterfile depicting population density in 2015(100 m reso-lution)was obtained from WorldPop 25 and used toextract population density at each D2D entry coordi-nates.Since the raster did not cover the entirety of theworking area,entries located outside of the rasters datagrid were applied a buffer averaging the values found ina 550 m radius.In the absence of suitable poverty geo-data for Negombo,a raster file depicting the number ofunderweight children under five years old(in the year2000)with a 2.5-min resolution was obtained from theSocioeconomic Data and Applications Center(SEDAC)26.Hunger data for each D2D entry coordinate wasextracted from the raster and used as proxy data forpoverty.A shapefile containing land types(in 2012)based on the national 7-class classification scheme wasobtained from the World Bank Group 27 and used todetermine land type for every D2D entry coordinate.The R package ggmap 28 was used to plot all maps,using background tiling sourced from Stamen Design(using data by OpenStreetMap 29),available under CCBY 3.0 license.Data analysisData manipulation and analysis was performed using theR statistical software environment version 3.4.3 30.The use of specific R packages for particular purposes isdetailed below:Identification and management of GPS outliersThe GPS data was checked to detect any erroneous en-tries caused by coordinate inaccuracy by automated re-cording systems 31.These inaccuracies were mostlyrepresented by coordinates ending up outside the visitedward,or in the ocean.These were considered to occurat random,and a system for outlier coordinate detectionwas created.This system was irrelevant for the SP stagesince coordinates for all the vaccination points wereknown.For the D2D locations,due to the lack of refer-ence coordinates,this discrimination was performed byspatial clustering.Using the dbscan function from thefpc package 32,clusters of vaccination coordinateswere determined.The function required 2 parameters tobe specified in advance:the size of the epsilon neigh-bourhood was set at 0.005,and the minimum number ofneighbours was set to 3.Clusters containing 20%ofthe total points for a given day and team responsiblewere considered outliers.The detection system wascomplemented by a visual screening of the coordinates.At the end of the process,836 entries were marked asoutliers and not included in the regression analysis dueto the need for spatial accuracy,however they were in-cluded in the vaccination coverage analysis after adjust-ing their ward according to Mission Rabies workingschedules.The assumption that the outliers occurred atrandom was checked by comparing the distribution ofthe variables included in the regression model betweenthe outlier non-outlier entries.Estimation of coverage by wardVaccination coverages for each ward were calculatedbased on the number of dogs marked with a collar orpaint sighted during the survey out of the total num-ber of dogs sighted.The 95%binomial confidenceinterval(CI)was calculated using the binom.test func-tion from base R 30,which carries out an exact bi-nomial test.The over function from the rgeos package33 was used to match the coordinates from the datawith the ward shapefile,which was imported usingthe rgdal package 34.Analysis of dog demographicsThe dog population in Negombo was estimated usingthe Chapman estimator 35 for mark and recapture.The dog population density was calculated using thearea for the Mission Rabies working zone(30km2).The95%CI for the population size was calculated using theciChapman function from the recapr package 36,withthe default bootstrap method.Data obtained from theD2D stage was used to study the dog demographics onsex,age,ownership and neuter status of the dogs,as itcontained information on both the owned and straypopulations.In order to determine any relationshipbetween the dog-related variables(sex,age,ownershipstatus,vaccination status an