Estimation of dog population in Nasarawa state Nigeria: a pilot study

Introduction Estimation of dog population is relevant in Animal Health Planning; some of the benefits include rabies control and possible elimination, estimation of quantity of dog vaccines and drugs required in the state, policy development and implementation. Methods A cross-sectional study was conducted to estimate the population of dogs in Nasarawa state; a local government area (LGA) was randomly selected from each of the three senatorial districts and two wards were selected randomly from the selected LGA's. Three hundred and thirteen questionnaires were administered through face to face interview with dog owners and their dogs in view. Results Analysis indicated 97.7% of the dogs were local breeds, 1.7% mixed and 0.3% exotic breeds. Guard dogs were 77% and 23% were used for hunting. Majority of the dogs (67.5%) were owned/stray while 32.5% were owned/confined. In Nasarawa state, 21% of the dogs were vaccinated and 79% had no vaccination history. The low vaccination rate indicates possible threat to animal and human health; hunting dogs are possible source of rabies introduction into their immediate communities from contact with wild reservoirs of the virus. Majority of dogs were between 1-5 years (73%) and more female dogs (52.5%) than males (47.5%) were reported. The dog to household ratio was 1.1:1 while the dog to human ratio is 1.1:6. Estimated number of dogs in Nasarawa state was 462,586 dogs. Conclusion Proper sensitization of dog owners on annual antirabies vaccination against rabies in dogs and postexposure prophylaxis in humans is recommended. The local authorities should institute effective measures for the control of stray dogs to prevent the risk of dog bites and other environmental hazards posed by such dogs. The state government should enact and enforce laws on responsible dog ownership to include compulsory annual vaccination of all dogs. This exercise should be replicated in other states of the federation for a comprehensive national dog ecological data necessary for planning, policy development and implementation.


Introduction
The close relationship between dog and man has existed for several centuries with several advantages and disadvantages [1]. The need for proper identification and management to harness both positive and negative aspects of this relationship is essential for Veterinary Public Health Services in a community [2,3]. In nearly all parts of the world, dogs pose serious human health, socioeconomic, political, and animal welfare problems [4]. Dogs have been reported to be the principal vectors and reservoirs of rabies in Africa [5]. Rabies is a widespread, neglected and under-reported zoonosis with an almost 100% case fatality rate in humans not treated on time, and causing a significant social and economic burden in many countries worldwide [6]. Domestic dogs are the main reservoir of rabies throughout the developing world [7] enhanced by the persistence of rabies virus in the local dog population and greater movement of infected dogs [8]. More than 90% of all human deaths from rabies occur in the developing world [9]. In Africa and Asia, an estimated 24,000-70,000 people die of rabies each year [10] and the domestic dog is the main source of exposure and primary vector for this important human disease [11]. Mass vaccination of dogs which is also the gold standard is the most successful method for control and possible elimination of dog mediated rabies [12][13][14][15]. Also, dogs may harbour a wide range of parasites with zoonotic potential causing health risk to humans [16]. Studies on the use of dogs in Nigeria indicated that people keep dogs for companionship as pet, house guard, assistance for hunting of wildlife and as food animal. Their perceived economic and social worth depends on values attached by the various communities they exist [17].
In industrialized countries, dogs have been trained to remarkably high adaptation to human needs in health promotion; adjustment of the elderly, recovery from illnesses, guiding the blind, assisting the deaf, assisting persons that are impaired in their mobility and to alert epileptic patients that a seizure is imminent, consequently the owner can sit down or take some medications before a seizure strikes [1,18] [20]. The population size, ecology, and proportion of ownerless dogs in a community, as well as accessibility of dogs to vaccination campaigns and public attitude towards rabies control programmes are valuable information for planning and evaluation of anti-rabies campaign [20]. The cross-sectional study method that combines direct street count with the administration of questionnaire or door-to-door interview of urban and rural residents is the traditional technique for dog population studies in African countries.
Determination of dog population density (dogs/km 2 ) from established indicators of dog abundance (dog to human ratio and dogs per household) is one recommended procedure [17,27]. The sizes of different segments of a dog population depend heavily on the proportion of human population keeping, tolerating or rejecting dogs in their neighbourhood [19]. The WHO "Guidelines for dog rabies control" has stressed the need for research on dog populations and ecology in urban and rural areas [17]. Lack of reliable estimates of dog populations hampers rabies control campaigns in developing countries, as cost benefit analysis of control strategies cannot be made accurately [17].  [28,29]. The state has a total area of 27,117 km 2 (10,470 sq. mi) and a population of about 1,826,883, according to the 2006 population census. Nasarawa state has 13 local government areas [28,29]. The map of Nasarawa state and the 3 senatorial districts indicated in Figure 1 and Figure 2.

Methods
Methodology: a cross-sectional study of the state was designed using multistage sampling method to obtain representative results. Nasarawa state has 13 LGA's, 195 electoral wards in 3 Senatorial districts. Selection of LGA's; One LGA was randomly selected by draw from Nasarawa South (NS), Nasarawa West (NW) and Nasarawa North (NN). These LGA's were selected to cover the three senatorial districts in the state. The LGA's selected were Lafiya with 13 wards (NS) which is the state capital, Keffi has 10 wards (NW) and Nasarawa Eggon with 14 wards (NN). Two wards were selected randomly by draw where the study was conducted. Selected wards include Akurba, Jigdawa, Iya I, Agunji Ogbagi, Angwan Moyi and Gayam. Three hundred and thirteen questionnaires were administered in the six wards.
Questionnaire design: the questionnaires that were used for this study was designed by consultants in the field. Section A consisted of enumerator information; name of state, name of location, name of agent, email address, telephone number, date of interview, date of submission and date received. Section B (Animal Information); name, identification mark, breed, purpose, management system, age, sex, source of dog and vaccination history. Section C had animal owner information; name of owner, telephone number, occupation, street address/description and educational status.

Conclusion
The dog to house hold ratio was 1.1:1, while the dog to human ratio was 1.1:6. Estimated number of dogs in Nasarawa was 462,586.
There was a very low vaccination rate of dogs in Nasarawa state.

Competing interests
The authors declare no competing interests.