Implications For Rabies Control Research Articles

Estimation of the Rural Dog Population Within a Mega-City: An Example in Jiading District, Shanghai.

Rural dog populations have long been recognized to be inadequately managed in terms of disease control and prevention. In this study we consider dog management in rural Shanghai and its implications for rabies control in the entire metropolitan area of Shanghai. The prerequisite to improve rabies vaccination coverage in rural Shanghai depends on a proper enumeration of the total rural dog population. In this study we selected one of the nine administrative districts in Shanghai (Jiading), within which there are 7 towns and 2 industrial zones (township-level division) that contain agricultural areas. A total of 9 villages (rabies model villages) were chosen from each township-level division in Jiading, and an additional 3 non-model villages were also included in the study. A household questionnaire survey was implemented in all 12 villages recruited. In 3 of the model villages and the 3 non-model villages chosen as a comparison, two methods of enumeration—a sight-resight survey and a household census survey—were implemented. Results from the household survey in these 6 villages showed that among the total 1,560 owned dogs, 80.4% were Chinese Garden Dogs, 69.1% were aged 1 to 3 years, 49.2% were homebred, and 88.3% were kept for the purpose of guarding the house. However, only 3.7% of the owned dogs were desexed. There was a higher proportion of chained or confined dogs in model compared to non-model villages. The model villages had an absolute rabies vaccination coverage of 100% among its owned dog population and a smaller number of stray dogs. It was also identified that the two enumeration methods yielded similar counts (P = 0.12), particularly within smaller villages. From the questionnaire survey implemented within all 12 villages and based on the average human-to-dog ratio, the total rural dog population of Jiading district was estimated to be 24,058. This study generated information on the general demographics of the rural dog population in Jiading, and demonstrates an approach to the study of rural dog populations within the context of a megacity. In such a context, rural dog populations need to be considered as a critical component of animal and public health.

Movement patterns of free-roaming dogs on heterogeneous urban landscapes: Implications for rabies control

In 2015, a case of canine rabies in Arequipa, Peru indicated the re-emergence of rabies virus in the city. Despite mass dog vaccination campaigns across the city and reactive ring vaccination and other control activities around positive cases (e.g. elimination of unowned dogs), the outbreak has spread. Here we explore how the urban landscape of Arequipa affects the movement patterns of free-roaming dogs, the main reservoirs of the rabies virus in the area. We tracked 23 free-roaming dogs using Global Positioning System (GPS) collars. We analyzed the spatio-temporal GPS data using the time- local convex hull method. Dog movement patterns varied across local environments. We found that water channels, an urban feature of Arequipa that are dry most of the year, promote movement. Dogs that used the water channels extensively move on average 7 times further (p = 0.002) and 1.2 times more directionally (p = 0.027) than dogs that do not use the water channels at all. They were also 1.3 times faster on average, but this difference was not statistically significant (p = 0.197). Our findings suggest that water channels can be used by dogs as ‘highways’ to transverse the city and have the potential to spread disease far beyond the radius of control practices. Control efforts should focus on a robust vaccination campaign attuned to the geography of the city, and not limited to small-scale rings surrounding cases.

Dog ecology and its implications for rabies control in Gwagwalada, Federal Capital Territory, Abuja, Nigeria

The objectives of this study were to determine the characteristics of a dog population, including their accessibility to vaccination and health care, in urban and semiurban areas of Gwagwalada, Abuja, Nigeria. Direct street counts and a house-to-house survey of city streets were performed. A total of 451 households were surveyed comprising 43.7% urban and 53.3% semiurban areas. A total of 848 owned dogs were identified, along with 3,115 corresponding humans. With a dog-to-human ratio of 1:3.7, the dog population in the study area was estimated as 103,758. A total of 396 dogs were counted on the streets with the greater proportion (74%) in semiurban areas. Most dogs in semiurban areas (77.3%) had no certificate confirming vaccination against rabies, compared to 47.2% in urban areas (p=.004). The majority of dogs in the urban (60.9%) and semiurban (82.0%) were free roaming. In the multivariable model, age, presence of a collar, region, sex, use and having ever visited a veterinarian were significantly associated with rabies vaccination. The majority (125/197, 63.5%) of respondents with higher education were willing to pay more for the healthcare needs of their dogs as opposed to those with a lower level of education (93/251, 37.1%, p=.001). The study revealed a high dog population density, vaccination coverage below WHO recommendation of 70% and generally reduced healthcare-seeking behaviour among dog owners in Gwagwalada, Abuja, Nigeria.

Population Dynamics of Owned, Free-Roaming Dogs: Implications for Rabies Control.

BackgroundRabies is a serious yet neglected public health threat in resource-limited communities in Africa, where the virus is maintained in populations of owned, free-roaming domestic dogs. Rabies elimination can be achieved through the mass vaccination of dogs, but maintaining the critical threshold of vaccination coverage for herd immunity in these populations is hampered by their rapid turnover. Knowledge of the population dynamics of free-roaming dog populations can inform effective planning and implementation of mass dog vaccination campaigns to control rabies.Methodology/Principal FindingsWe implemented a health and demographic surveillance system in dogs that monitored the entire owned dog population within a defined geographic area in a community in Mpumalanga Province, South Africa. We quantified demographic rates over a 24-month period, from 1st January 2012 through 1st January 2014, and assessed their implications for rabies control by simulating the decline in vaccination coverage over time. During this period, the population declined by 10%. Annual population growth rates were +18.6% in 2012 and -24.5% in 2013. Crude annual birth rates (per 1,000 dog-years of observation) were 451 in 2012 and 313 in 2013. Crude annual death rates were 406 in 2012 and 568 in 2013. Females suffered a significantly higher mortality rate in 2013 than males (mortality rate ratio [MRR] = 1.54, 95% CI = 1.28–1.85). In the age class 0–3 months, the mortality rate of dogs vaccinated against rabies was significantly lower than that of unvaccinated dogs (2012: MRR = 0.11, 95% CI = 0.05–0.21; 2013: MRR = 0.31, 95% CI = 0.11–0.69). The results of the simulation showed that achieving a 70% vaccination coverage during annual campaigns would maintain coverage above the critical threshold for at least 12 months.Conclusions and SignificanceOur findings provide an evidence base for the World Health Organization’s empirically-derived target of 70% vaccination coverage during annual campaigns. Achieving this will be effective even in highly dynamic populations with extremely high growth rates and rapid turnover. This increases confidence in the feasibility of dog rabies elimination in Africa through mass vaccination.

Identification and analysis of dog use, management practices and implications for rabies control in Ilorin, Nigeria

Dog use and associated management practices were investigated in Ilorin, the capital city of Kwara State, Nigeria from August to October 2010. All identified 16,348 household compounds in the city were investigated. Five hundred (500) questionnaires were directly administered at household and compound levels to capture data on socio-economic profile of dog owners, reasons for keeping dogs and types of management system practiced. The results indicated that majority [621, n = 1,258 (49.4%)] of dogs were kept primarily for security of premises. Some 205 (16.3%) were kept for breeding and commercial ventures, 184 (14.6%) were kept as pets, 103 (8.2%) were kept essentially for game hunting, 98 (7.8%) were used for multiple purposes and 47 (3.7%) were raised as source of meat. Dog management ranged from intensive (kennel confined) [331, (26.3%)], to extensive (free -roaming) system in 927 (73.7%) dogs. Dogs were kennel confined mostly [207, (16.5%)] in high income residential areas, while all dogs in transit areas were free-roaming. A positive correlation (r 2 =0.74) exists between extensive practice and dogs for meat production which were left to scavenge freely in the city. The implication of dog use and management practices in relation to rabies control in Ilorin city and its environs is discussed in this paper. Status of community hygiene and environmental health is contributory to rabies risk in the city. Improved community hygiene is needed to complement effective vaccination coverage of dogs for rabies control in the city.

Uptake of buried baits by badgers: Implications for rabies control in Great Britain and the delivery of an oral TB vaccine

AbstractThe British Government's contingency plan for the control of wildlife rabies is based on oral vaccination around a focal outbreak, with the option of the targeted lethal control of foxes (Vulpes vulpes) and badgers (Meles meles) using buried poisoned bait. We investigated uptake by badgers of nonpoison meat‐based baits buried along transects for 10 consecutive days in 1995. The original aim was to evaluate the likely effectiveness of this contingency option. However, the results are also pertinent to the development of an oral tuberculosis (TB) vaccine baiting strategy for badgers, for which research has primarily been carried out since this study was completed. Bait disappearance steadily increased over time, reaching an asymptote after 7 days. By incorporating iophenoxic acid biomarkers into baits, we showed that about 51% of subsequently captured badgers had consumed bait, the majority of which did so during the first 7 days. Bait uptake was significantly higher among adults. Rates of uptake by badgers of baits buried along transects could be increased by shortening the prebaiting period or extending the baiting period. However, considerably higher levels of uptake by adults and cubs are likely to be achieved by targeting bait deployment at badger setts, and this is now included in Britain's rabies contingency plan. Although meat‐based baits cannot be used for TB control, the relevance of these results to the delivery of an oral TB vaccine bait to badgers is discussed. © 2012 Crown copyright

A preliminary survey for changes in urban Fox (Vulpes vulpes) densities in England and Wales, and implications for rabies control

ABSTRACTA questionnaire was sent to 139 councils and 44 local mammal groups in England and Wales, requesting data on changes in urban Red Fox (Vulpes vulpes) densities between 1987 and 1997. Of 152 responses, 41% believed Fox numbers had increased, 42% believed Fox numbers were unchanged and 7% believed Fox numbers had decreased. Most of the increases were perceived to be due to increased food availability, and decreases due to sarcoptic mange (Sarcoptes scabiei). In the event of a rabies outbreak in Britain, the models used to determine control strategies are dependent on having sufficiently up‐to‐date urban Fox density data. This survey suggests that urban Fox density data for Britain should be updated in the near future.

Distribution and density estimates for urban foxes (Vulpes vulpes) in Melbourne: implications for rabies control

The distribution and density of red fox populations was investigated in metropolitan Melbourne from 1990 to 1993. Distribution data were collected from sightings reported by members of the public, from spotlight and active den surveys, and from trapping and road kills. Archival data suggested that resident populations of foxes have been present within the inner metropolitan area since the early 1940s. Contemporary fox populations were found to be extensively distributed throughout the urban area, with few 1-km 2 grids within a 5-km radius of the Central Business District not containing foxes. Density estimates were based on nearest-neighbour analysis of active natal dens in four field sites. Observations of cubs over a 4-year period at 17 dens within the field sites revealed a mean litter size of 4.36 cubs. Mean 4-year density estimates for each field site, immediately after the breeding season, were 0.47–2.55 dens km −2, which was estimated to represent 3–16 foxes km −2. Density estimates may be conservative, as family groups may contain more than one non-breeding adult. The implications of these data are discussed with respect to the potential role of the urban fox in the epidemiology of rabies. It was concluded that fox populations at the field sites were of sufficient density to maintain a sylvatic epizootic of rabies.

Habitat utilisation by urban foxes (Vulpes vulpes) and the implications for rabies control

Habitat utilisation by urban foxes (Vulpes vulpes) and the implications for rabies control

Fox Contact Behaviour and Rabies Spread: A Model for the Estimation of Contact Probabilities Between Urban Foxes at Different Population Densities and Its Implications for Rabies Control in Britain

1. Contacts between susceptible and infectious individuals determine how fast a disease will spread. However, they are difficult to measure in the wild, and most models of disease spread have been forced to use estimated or derived values. 2. In this paper, a mathematical relationship between fox home range size and population density is derived from the literature and combined with behavioural data on movement patterns and encounters from urban Bristol, UK to formulate a predictive model of inter-group contact probabilities over a range of population densities. 3. This contact probability-population density relationship is used to formulate a revised version of the rabies model of Smith & Harris (1991), which is the model used by the Ministry of Agriculture, Fisheries and Food as the basis of its rabies control policy for an outbreak of the disease in an urban area of Britain. 4. The original and revised versions of the model are compared in terms of their predictions for the rate of rabies spread and their implications for rabies control in specific urban areas. 5. An equivalent probability of successful rabies control is achieved by 5-15% lower fox control for the revised model compared with the original one. The greatest differences between the probability of successful rabies control for a given level of fox control under the two versions of the model occur in winter. 6. The revised model predicts that the rate of rabies spread will be slower than predicted by the original model. This is due to the lower inter-group contact probabilities used in the revised model. Thus, there will be a greater chance of containment and elimination of the disease within a specified control area than was suggested by the original model. 7. The heterogeneous nature of the urban landscape probably results in a lower frequency of contacts than would be observed between foxes living at the same densities in rural environments.