A CROSS-SECTIONAL SURVEY ON DOG ECOLOGY AND DOG ANTI-RABIES VACCINATION COVERAGE IN SELECTED AREAS IN SRI LANKA

INTRODUCTION maintain herd immunity among animal reservoirs (Malerczyk, 2012; WHO, 2013; Rupprecht et al., 2008). A Rabies is a fatal and neglected zoonotic disease that study conducted in Sri Lanka in 1997 to evaluate the causes nearly 60,000 human deaths worldwide annually progress of rabies control measures revealed that the (Hampson et al., 2015). During the last century, several vaccination coverage reached by parental mass countries have demonstrated that controlling rabies vaccination campaigns was 57.6% (Matter et al., 2000). through annual mass vaccination campaigns for domestic Studies conducted in Abia State of Nigeria and Thangsong dogs is the most reliable and effective way for elimination district of Thailand have estimated anti-rabies vaccine of rabies (Coleman et al.,1996;Touihri et al., 2011). coverage of household dogs as 47.9% and 44% Dogs are the main transmitter of rabies for humans in respectively (Awoyomi et al., 2007; Kongkaew et al., Africa and Asia, including Sri Lanka where rabies is 2004). It is mentioned that vaccination coverage against endemic. Out of reported rabies cases in animals, over rabies varies according to demography which includes 96% are among dogs and 95% of the human rabies deaths dog: human ratio, confinement status , the size of the total are due to rabid dog bites (Nanayakkara et al., 2003; dog population and free-roaming dog population with WHO, 2014). Vaccination of dogs has been identified as undetermined ownership status (Knobel et al., 2008;Wild an important control measure. The World Health et al, 2005). Further, an understanding dog ecology has Organization (WHO) recommends that at least 70% of been recognised as a key factor in designing an effective the domestic dog population should be vaccinated during rabies control programme in rabies endemic countries annual mass vaccination campaigns to achieve and (Gbeminiyi et al., 2014; Coleman et al.,1996; Bearn et SUMMARY: Dogs are the main transmitter of rabies virus for humans in Sri Lanka. Therefore, updated information on the dog rabies vaccination coverage and dog ecology are essential for launching an effective rabies elimination program in the country. A descriptive cross sectional study was conducted in 120 clusters. Counts recorded at the vaccination centres were considered as the capture sample. In the recapture sample, data collected on humans and dogs through the questionnaire survey administered on households were considered. Number of dogs vaccinated against rabies and the total number of people in the dog-owning households that attended the vaccination centres were 2508 and 8690 respectively. The household survey of the study included 2207 households, which includes 8650 family members. Among these households, 774 houses had dogs which included 3382 family members. From the 2933, free-roaming owned dogs and free-roaming dogs with undetermined ownership counted through the transect line, 1413 had been marked in the study areas. Out of 838 owned confined and owned freeroaming dogs found during the questionnaire survey administered on 2207 households, 579 were recorded as recaptured. The estimated human population of the area surveyed was 34,901. The tabulated ratio of the total dog population in total human was 1:6.7 and owned dog population to human ratio was 1:9.6. The estimated owned dog population was 3630 and the total dog population was 5205. The total dog vaccination coverage is 48% (2508/5205).Owned (confined and free-roaming) dog vaccination coverage achieved was 69%. Vaccination coverage among owned free-roaming dogs was 54% and significantly low (P<0.005), compared to owned confined dogs which was 77% . Majority of the dogs owned were local breeds (90.5%) aged between 1 and 5 years old. Findings revealed that 34% of the owned dogs were allowed to roam freely during the day. During annual mass vaccination campaigns, there should be a method to include dogs in all three categories i.e. Owned confined, owned free-roaming and dogs with undetermined ownership status. Considering confinement status practiced, allowing dogs to roam freely should be discouraged. This could potentially be acquired through implementing educational programs and new legislations bound with legal means. http://doi.org/10.4038/slvj.v64i1A.18

. ecology and vaccination coverage of dogs against rabies. There had been a considerable variation in the dog: The findings of this study are expected to be a guide for the human ratio, which commonly lies between 1:6 and 1:10. national rabies control program in Sri Lanka. A survey done in Africa revealed that the dog: human ratio is 1: 21.2 in urban areas, while rural areas have a ratio of MATERIALS & METHODS 1:7.4 (Robinson et al.,1996;Kaare et al., 2009;Awoyomi et al., 2007;Oboegbulemand et al., 1989 ). In Sri Lanka, Study design and sampling there have been only a few studies that have tried to estimate the dog population size in urban or rural areas; a This was a cross-sectional analytical study conducted in demography and dog ecology study was conducted in the year 2013,using the capture recapture method. The Mirigama, Gampaha which revealed a 1:4 dog: human study was carried out in two provinces (Western and ratio (Matter et al., 2000) and another study carried out in Southern) of Sri Lanka. Two Divisional Secretariats (DS) National Institute of Health Sciences field practice area of from each province were selected based on the average Kalutara district in 2006 has revealed a 1: 8.5 dog:human human population (http://www.statistics.gov.lk). Figure 1 ratio (Pimburage et al., 2011). However the dog illustrates the districts, divisional secretariats (DS) and population information has not been updated for the last 7 public health inspector (PHI) areas selected for this study. years in Sri Lanka.
The total human population and the dimension of the An evaluation of dog anti-rabies vaccination coverage selected areas are also indicated in Figure 1. Selected PHI and other factors influencing the progress of the on-going areas were Welipanna, Raigama from Matugama and rabies control program was a prerequisite to make Bandaragama DS areas and Bambaranda and Akuressa necessary changes for the future planning of the program. from Dikwella and Akuressa DS areas. Among the Estimation of the total dog population is essential in order selected PHI areas in Bandaragama and Akuressa are to purchase the number of vaccines required for a national urban areas while selected PHI areas in Matugama and anti-rabies campaign and to determine the vaccination Dikwella are rural areas. During this study the total area  Figure 1: Flow chart indicating sampling established for a day for three consecutive days, Capturing phase at the temporary vaccination centre comprising a total of 30 temporary vaccination centres for the period. Each day capturing and recapturing with As the initial step, one day ahead, people were made transect line counting was carried out.
aware of the date, time and the place of upcoming antirabies vaccination program using loudspeaker Duration of the study announcements apart from the posters displayed one week prior to the program. Dogs were vaccinated intramuscularly using a commercial anti-rabies vaccine This study was conducted in line with the owned dog recommended for the National anti-rabies control (owned confined and owned, free-roaming) vaccination program. Average distance between two adjoining team of national anti-rabies campaign in order to cut down vaccination centres was 1 km. Five teams of 2 persons the cost of the study. The national anti-rabies campaign is operated 10 vaccination centres per day, 5 in the morning conducted at the district level and each district has a team and 5 in the evening. of people to cover the district in order to establish an At the point of vaccination, one person was engaged in achievable vaccination coverage in the district. Three full vaccination and marking of all vaccinated dogs with red days (Area 1: February 19-21, Area 2: April 26-28, Area 3: collars while the other person collected information about August 10-12, Area 4: November 15-17) were spent to the vaccinated dogs (age, sex, vaccine history) and the cover one PHI area (30 clusters = 10 vaccination households (name and address, number of dogs and centres/per day in 3 days in each PHI area). The area number of family members in the household). During the covered by a vaccination centre in one day in the study is 2 capturing phase free-roaming dogs with undetermined approximately 0.8 km . In-order to cover all the selected ownership were not vaccinated. PHI areas, 10 months has to be spent as the study followed district antirabies campaigns due to limited funding and Recapturing through household survey human resources.
Once the vaccination was completed, a household Categories of dogs included in the study survey was conducted within the 500m radius from the vaccination centre. The household survey was done either The dogs included in the study were considered under on the same day afternoon or on the following day following three categories.
morning for vaccination centres conducted in the morning · Owned, (continually) confined dogs and afternoon respectively to minimize violation of · Owned, free-roaming (some or all of the day or night) marked-recapture model assumptions i.e. creating a dogs closed population, subjects are not losing their collars, · Free-roaming dogs with undetermined ownership estimating probability of capturing a marked subject is equal to the proportion of marked subjects in the status was visited totalling up to a maximum of 25. This method total number of dogs recorded (n ) and total number of 2 was adopted to avoid re-visit of households served by the dogs found marked in the recapturing phase (m) were adjoining vaccination centres. Number of persons in the considered. For the estimation of the human population household and information about their pets [sex, age, number of family members (number of members in the breed, confinement status, collar marked or not, whether families to which the dogs belong) recorded at the anti-rabies vaccination was given or not] in the vaccination centres (n ), total number of family members 1 household were recorded. Numbers of marked and (n ) and number of family members (the total number of 2 unmarked dogs outside the households were also recorded people in the dog-owning households that attended the on a separate sheet in parallel with the household survey vaccination centre) of marked dogs (m) in the recapturing {owned dogs, owned free-roaming (dogs who are allowed phase were noted. The total population size (N) is to roam freely out of the household premises without calculated as: N=å å m (Chao et al., 2001). restrictions) and free-roaming dogs with undetermined Ethical clearance for the study was obtained from the ownership}.
Ethics Review Committee of the Faculty of Medicine, University of Colombo.

Recapturing through Transect study RESULTS
A second recapture of marked and unmarked dogs was carried out in a transect study to estimate the total dog Populations captured and recaptured population. Once the vaccination was done, on the following day morning (6.00am -7.30am), in the area A total of 2508 dogs presented to temporary served by the vaccination centres, a daily transect line vaccination centres during the period of survey was count of marked and unmarked dogs were done. A person marked with red collars after vaccination. Total number of travelling by a car, on a pre-defined transect line following family members (number of members in the families in specified roads around and across the temporary which the dogs belong) recorded at that time was 8690. vaccination centres, counted (recaptured) all the visible From the 2933, owned, free-roaming dogs and freedogs on the roads and inside household premises, with and roaming dogs with undetermined ownership counted without collars separately. Inclusion of 500m buffer through the transect line count, 1413 had been marked at zones during counting prevented counting of dogs that the temporary vaccination centre. roamed into the study area from adjacent areas.
There were 2207 households in the four DS divisions Using the same method, an overall recount of marked and all were included in the study during the recapture and unmarked dogs was done at the end of three day phase. There were 838 dogs and the mean age of the vaccination program in the entire area included for the sample dog population was 3.5 years. program.

Management of dogs by the owners Data collection, analysis and ethics
During the household survey, it was found that 552 The Veterinary surgeons and public health inspectors (66%) dogs were kept restrained by caging 245 (29%) or attached to the National anti-rabies control program were tying 307 (37%). Remaining 286 (34%) owned dogs were trained to collect the data. The interviewer administered allowed to roam freely during the day. Among 552 questionnaires and data collection sheets used for the confined dogs, 425 (77%) were vaccinated and out of 286 survey were pre-tested.
unconfined owned dogs, only 154 (53.8%) were The data were analysed using Statistical Package for vaccinated (Table 1). The percentage of females (34.3%) Social Sciences (version 10). Descriptive statistics was were higher than that of males (29.1%) in free-roaming used to describe the information. The associations dogs (dogs who are allowed to roam freely out of the between dog confinement status and rabies vaccination household premises without restrictions). coverage were assessed using chi-square test and comparison of means using sample t-test. The data were Dog population estimations and Dog anti-rabies considered significant at p = 0.05. vaccination coverage The human and dog population, including free-roaming dogs with undetermined ownership status was estimated Owned dog (confined and free-roaming) population for the study area, using a capture-recapture approach and was estimated as 3630 (95% CI: 3465-3793). The the Lincoln-Petersen estimator inorder to determine total tabulated vaccination coverage of these dogs was 69% vaccination coverage in the dog population (Chao et al., (n=2508). Out of the total confined dogs, 77% were 2001; Efford et al., 2012). vaccinated whereas it is only 54% in the dogs allowed for The estimation is based on the number of marked free-roaming. The dog population including owned, free-(capture) and unmarked populations counted separately n n / 1 2 roaming dogs and free-roaming dogs with undetermined direct relevance for the designing of appropriate and ownership, was estimated as 5205 (95% CI: 5000-5401) effective dog rabies control strategies in Sri Lanka. in the study area and calculated vaccination coverage was The study shows that vaccination coverage among the 48% (2508/5205). Only 58.8% (n=17) of the owned dogs total dog population as 48%. Among less than three under 3 months of age had been vaccinated. months old owned dogs 58.8% were vaccinated. The The vaccination coverage was low in local breeds vaccination coverage was found low (68%) in local breeds (68%, n=517) compared to purebred dogs (78%, n=62). compared to purebred dogs 78%. From the domestic dogs included in the survey, 69% For estimating dog population densities in relation to (n=579) were vaccinated previously through the National human population, WHO recommendation is to compile anti-rabies control program and 5.25% (n=42) were 500 to 5000 households in a major survey (Lwanga et vaccinated by the private sector. Further, survey findings al.,1991;WHO/WSPA,1990). Since this study includes revealed that 34% of the owned dogs were allowed to 2207 households, sample size of the study is sufficient to roam freely during the day and the vaccination coverage obtain an accurate estimation. of this population of dogs were significantly lower than Another important aspect noted was vaccination that of confined dogs, either leashed or caged (P<0.005).
coverage of local breeds was comparatively lower than that of other breeds (pure breed or cross breeds). This may Human population be attributed to the low priority given to this breed by most of the owners. Number of family members recorded at the vaccination Mean age of the sample dog population was found to be centres were 8690. The household survey of the study 3.5 years, and in general, the majority of dogs in the included 2207 households, which includes 8650 family developing world is very young and short-lived (De members. Out of the 2207 households 774 houses had Balogh et al., 1933;Davlin et al., 2012). A lack of dogs with 3382 family members. The estimated human responsible pet ownership towards caring for dogs and population of the area surveyed was 34,901 (95% CI: lack of facilities could be the possible reasons for this 33,624.56-36,177.85). The average number of people in a observation. This could lead to changes in the dog family was 4 per household, however, it ranged from 1 to turnover rate, thus affecting the total vaccination 14.
coverage. Vaccination coverage should exceed 70% as per The ratio of the total dog population to total human was WHO recommendation to acquire protective levels of 1:6.7 and owned dog population to human ratio was 1:9.6. herd immunity among the dog population in order to eliminate dog rabies in an endemic country (WHO, 2013).

DISCUSSION
Our total vaccination coverage (48%) is below the recommended level. Under normal circumstances, This survey was conducted after 7 years of a similar vaccination programs are conducted only for a half a day study conducted in the country to study dog population on working days (Monday to Friday) in a particular place ecology and vaccination coverage of dogs against by the National anti-rabies control program. The principal rabies.We were able to identify several important features reason for vaccination coverage of 69% is partly because of dog ecology and vaccination coverage that have a of the difficulty in bringing 34% of the owned free Dog ecology and dog anti-rabies vaccination 5 roaming dogs to the vaccination centres within the short second opportunity to get the dogs vaccinated free of time period. There were instances where certain charge is recomended to the campaign. Vaccination household members, ie.elders or females, could not catch/ coverage can be further improved if there are vaccine restrain owned free-roaming dogs due to the dogs' centres conducting in weekends and public holidays. In temperament. Also there is a group of dog owners who do order to improve vaccination coverage an incentive such not present their dogs for vaccination due to negligence. as a colourful dog collar would be a way to attract dog These limitation could have overcome by increasing the owners to vaccination points. During annual mass duration of vaccination centres, employing dog catchers, vaccination campaigns, there should be a method to and by educating owners about the methods of restraining include dogs of all three categories i.e. owned confined, dogs. owned free-roaming and dogs with undetermined A study conducted in Bali, Indonesia has reported that ownership status and daily monitoring of vaccination at least 40% of vaccination coverage should be coverage is recommended. maintained in an island for 4 to 5 years to eliminate rabies Considering the confinement status practiced, effectively (Townsend et al., 2013). Therefore, the allowing dogs to roam freely outside the household present vaccination coverage may be sufficient to premises should be discouraged. This could potentially be eliminate rabies if we can maintain it sustainable among acquired through implementing educational programs the total dog population for an appropriate period. and new legislations bound by legal means. Animal birth According to the results obtained in the household control program should also strengthen to reach survey, a higher percentage of the owned dogs were males elimination of unwanted breeding of dogs in the (79%), which was similar (65.7% domestic dogs were community. males) to what was observed previously in the Kalamulla Public Health Inspectorate (PHI) area in Kalutara District,