Movement patterns of free-roaming dogs on heterogeneous urban landscapes: Implications for rabies control.
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ABSTRACT:
SUBMITTER: Raynor B
PROVIDER: S-EPMC7234908 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:Rabies 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 FINDINGS:We 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 SIGNIFICANCE:Our 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.
| S-EPMC4636342 | biostudies-literature
Project description:Canine rabies can be effectively controlled by vaccination with readily available, high-quality vaccines. These vaccines should provide protection from challenge in healthy dogs, for the claimed period, for duration of immunity, which is often two or three years. It has been suggested that, in free-roaming dog populations where rabies is endemic, vaccine-induced protection may be compromised by immuno-suppression through malnutrition, infection and other stressors. This may reduce the proportion of dogs that seroconvert to the vaccine during vaccination campaigns and the duration of immunity of those dogs that seroconvert. Vaccination coverage may also be limited through insufficient vaccine delivery during vaccination campaigns and the loss of vaccinated individuals from populations through demographic processes. This is the first longitudinal study to evaluate temporal variations in rabies vaccine-induced serological responses, and factors associated with these variations, at the individual level in previously unvaccinated free-roaming dog populations. Individual-level serological and health-based data were collected from three cohorts of dogs in regions where rabies is endemic, one in South Africa and two in Indonesia. We found that the vast majority of dogs seroconverted to the vaccine; however, there was considerable variation in titres, partly attributable to illness and lactation at the time of vaccination. Furthermore, >70% of the dogs were vaccinated through community engagement and door-to-door vaccine delivery, even in Indonesia where the majority of the dogs needed to be caught by net on successive occasions for repeat blood sampling and vaccination. This demonstrates the feasibility of achieving population-level immunity in free-roaming dog populations in rabies-endemic regions. However, attrition of immune individuals through demographic processes and waning immunity necessitates repeat vaccination of populations within at least two years to ensure communities are protected from rabies. These findings support annual mass vaccination campaigns as the most effective means to control canine rabies.
| S-EPMC4230884 | biostudies-literature
Project description:Australia is currently canine rabies free. However, communities located on the northern coastline-such as the Northern Peninsula Area (NPA), Queensland-are at risk of an incursion due to their large populations of susceptible free-roaming dogs and proximity to rabies-infected Indonesian islands. A rabies-spread model was used to simulate potential outbreaks and evaluate various disease control strategies. A heterogeneous contact structure previously described in the population of interest-explorer dogs, roamer dogs and stay-at-home dogs-was incorporated into the model using six spatial kernels describing contacts between dog roaming categories. Twenty-seven vaccination strategies were investigated based on a complete block design of 50%, 70% and 90% coverage for each of the three roaming categories to simulate various targeted vaccination strategies. The 27 strategies were implemented in four population structures in which the proportion of dogs in each category varied-explorer dominant, roamer dominant, stay-at-home dominant and a field population (based on field estimates of population structure). The overall vaccination coverage varied depending on the subpopulation targeted for vaccination and the population structure modelled. A total of 108 scenarios were simulated 2000 times and the model outputs (outbreak size and duration) were compared to Strategy 14 (a standard recommended overall 70% vaccination coverage). In general, targeting explorer dogs-and to a lesser extent roamer dogs-produced similar outbreaks to Strategy 14 but with a lower overall vaccination coverage. Similarly, strategies that targeted stay-at-home dogs required a higher vaccination coverage to produce significantly smaller and shorter outbreaks. This study provides some theoretical evidence that targeting subpopulations of dogs for vaccination based on their roaming behaviours (and therefore risk of rabies transmission) could be more efficient than blanket 70% vaccination campaigns. Such information can be used in preparedness planning to help improve control of a potential rabies incursion in Australia.
| S-EPMC6638970 | biostudies-literature
Project description:Free roaming domestic dogs (FRDD) are the main vectors for rabies transmission to humans worldwide. To eradicate rabies from a dog population, current recommendations focus on random vaccination with at least 70% coverage. Studies suggest that targeting high-risk subpopulations could reduce the required vaccination coverage, and increase the likelihood of success of elimination campaigns. The centrality of a dog in a contact network can be used as a measure of its potential contribution to disease transmission. Our objectives were to investigate social networks of FRDD in eleven study sites in Chad, Guatemala, Indonesia and Uganda, and to identify characteristics of dogs, and their owners, associated with their centrality in the networks. In all study sites, networks had small-world properties and right-skewed degree distributions, suggesting that vaccinating highly connected dogs would be more effective than random vaccination. Dogs were more connected in rural than urban settings, and the likelihood of contacts was negatively correlated with the distance between dogs' households. While heterogeneity in dog's connectedness was observed in all networks, factors predicting centrality and likelihood of contacts varied across networks and countries. We therefore hypothesize that the investigated dog and owner characteristics resulted in different contact patterns depending on the social, cultural and economic context. We suggest to invest into understanding of the sociocultural structures impacting dog ownership and thus driving dog ecology, a requirement to assess the potential of targeted vaccination in dog populations.
| S-EPMC8213792 | biostudies-literature
Project description:(1) Background: Thailand has made significant progress in reducing the number of human and animal rabies cases. However, control and elimination of the last remaining pockets of dog-mediated rabies have shown to be burdensome, predominantly as a result of the large numbers of free-roaming dogs without an owner that cannot be restrained without special efforts and therefore remain unvaccinated. To reach these dogs, the feasibility, and benefits of oral rabies vaccination (ORV) as a complementary tool has been examined under field conditions. (2) Methods: ORV of dogs was tested in five study areas of four provinces in Thailand. In these areas, sites with free-roaming dogs were identified with the support of local municipal workers and dog caretakers. ORV teams visited each of five study areas and distributed rabies vaccine (SPBN GASGAS) in three bait formats that were offered to the dogs using a hand-out and retrieval model. The three bait types tested included: egg-flavored baits, egg-flavored baits pasted with commercially available cat liquid snack, and boiled-intestine baits. A dog offered a vaccine bait was considered vaccinated when the discarded sachet was perforated or if a dog chewed vaccine bait at least 5 times before it swallowed the bait, including the sachet. (3) Results: A total of 2444 free-roaming dogs considered inaccessible for parenteral vaccination were identified at 338 sites. As not all dogs were approachable, 79.0% were offered a bait; of these dogs, 91.6% accepted the bait and subsequently 83.0% were considered successfully vaccinated. (4) Conclusion: Overall, 65.6% of the free-roaming dogs at these sites were successfully vaccinated by the oral route. Such a significant increase of the vaccination coverage of the free-roaming dog population could interrupt the rabies transmission cycle and offers a unique opportunity to reach the goal to eliminate dog-mediated human rabies in Thailand by 2030.
| S-EPMC8065424 | biostudies-literature
Project description:Australia is canine rabies free but free-roaming, domestic dog populations in remote northern communities are at risk of an incursion due to proximity to rabies-endemic south-east Asia. Unrestricted contact between dogs could facilitate rabies spread following an incursion, and increase the impact on both dogs and people. Whilst dog vaccination is the foundation of rabies prevention, control strategies could be enhanced by understanding the temporal pattern of roaming and associated risk factors, so that movement restrictions can be targeted. Global positioning system datasets from 132 dogs in eight Indigenous communities in the Torres Strait and Northern Peninsula Area (NPA) of Australia were analysed using regression methods. The influence of risk factors (including age, sex, location, season and hour of day) on dogs' distance from their residences were assessed. Dogs roamed furthest in the NPA and during the dry season. Daily peaks in mean roaming distance were observed at 1000-1100?hrs and 1700-1800?hrs in the Torres Strait, and 1700-1800?hrs in the NPA. These findings demonstrate that understanding community-specific temporal roaming patterns can inform targeted movement restrictions during an outbreak of rabies in remote communities in northern Australia.
| S-EPMC6797733 | biostudies-literature
Project description:Canine rabies is endemic in urban India. A questionnaire was administered to 204 residents of the urbanised municipality of Panchkula in north India to assess the influence of gender, age, family size, social status and dog ownership, over the knowledge, attitudes and practices (KAP) towards rabies control and free-roaming dogs (FRD) in their locality. Bivariate analyses revealed significant knowledge gaps regarding crucial information on the control and transmission of rabies. Multivariable logistic regression models found that the respondents with a high/middle socio-economic status were likely to be more knowledgeable than those from low socio-economic levels (OR 3.03, 95%CI 1.5-6.0, p = 0.001). Households with children ?14 years of age were likely to be lacking in knowledge about rabies compared to households with older or no children (OR 0.5, 95%CI 0.3-0.9, p = 0.04). The attitudes and practices of the respondents towards rabies control was positive in households with a high/middle socio-economic status (OR 3.4, 95%CI 1.7-7.2, p = 0.0008) but poor in older (? 35 years) participants (OR 0.4, 95%CI 0.2-0.7, p = 0.001). It is concluded that rabies awareness campaigns should be developed and conducted to target sectors of the urban community such as those belonging to lower socio-economic sections and schools to improve the residents' knowledge and practices towards rabies. Educating dog owners about sterilising their pets is also recommended to alter the attitudes of the residents towards FRD population control.
| S-EPMC6508743 | biostudies-literature
Project description:The partitioning of production forests into discretely managed forest stands confronts animals with diversity in forest attributes at scales from point-level tree assemblages to distinct forest patches and range-level forest cover. We have investigated the movement and ranging patterns of male Common Chaffinches, Fringilla coelebs, in heterogeneous forest production landscapes during spring and summer in south-western Germany. We radio-tracked a total of 15 adult males, each for up to six days, recording locations at 10-min intervals. We then performed point-level tree surveys at all tracking locations and classified forest stand attributes for the areal covering of birds' ranges. Movement distances were shortest in beech forest stands and longer in spruce-mixed and non-spruce conifer stands. Movement distances increased with stand age in beech stands but not in others, an effect that was only detectable in a multilevel hierarchical model. We found negligible effects of point-level tree assemblages and temperature on movement distances. Daily range estimates were from 0.01 to 8.0 hectare (median of 0.86 ha) with no evident impact of forest attributes on ranging patterns but considerable intra-individual variation in range sizes over consecutive days. Most daily ranges covered more than one forest stand type. Our results show that forest management impacts the movement behaviour of chaffinches in heterogeneous production forest. Although point-level effects of movement distances are weak compared with stand-level effects in this study, the hierarchical organization of forest is an important aspect to consider when analysing fine-scale movement and might exert more differentiated effects on bird species that are more sensitive to habitat changes than the chaffinch.
| S-EPMC4081153 | biostudies-literature
Project description:An understanding of the core demographic characteristics of the sub-populations of FRD is essential to effectively implement both rabies control interventions through mass vaccination of FRD, and dog population control programmes. This study compares the data obtained following photographic sight-resight surveys in rural (Shirsuphal village in west India) and urban (Municipal Corporation Panchkula in north India) locations . A total of 263 and 1408 FRD were seen at least once through 617 and 3465 sightings in the rural and urban sites, respectively. The rural location had a lower proportion of females (OR 0.5, 95% CI 0.4-0.7) and a higher proportion of poor and fair conditioned dogs (OR 1.8, 95% CI 1.3-2.3) compared to the urban setting. The rural site also had fewer active FRD (OR 0.6, 95% CI 0.5-0.7) and FRD were less likely to be sighted within 20?m of garbage points (OR 0.3, 95% CI 0.2-0.3) compared to the urban site. The demographic composition of the FRD population was found to vary within the urban location, with the odds of sighting a de-sexed dog being significantly higher in residential areas compared to other areas. The study underlines the importance of knowing the demographic composition of FRD for implementation of effective interventions against rabies. Fewer female dogs in the rural location indicate that spaying could be an effective tool for dog population management in this setting, while presence of dogs within 20?m of garbage points in urban settings highlights that an improved garbage management may reduce the carrying capacity of the urban locality resulting in smaller FRD population. It is concluded that quick and low cost surveys can generate useful demographic data for FRD in urban and rural settings which can be useful to understand the epidemiology of rabies and its control.
| S-EPMC6851138 | biostudies-literature
Project description:Adequate vaccination coverage of free roaming dogs (FRD) against canine rabies is not achieved primarily due to difficulties in administering parenteral vaccinations to this population. One factor associated with this difficulty is the tendency of FRD to form groups, which increases their aggressive behavior, resulting in a significant risk of dog-bites for the vaccinators. This study investigated factors that influenced FRD forming groups and their home-ranges, using data obtained from photographic capture-recapture/sight-resight surveys conducted in rural Shirsuphal (584 sightings) and urban Panchkula (3208 sightings), India. In the rural site, older dogs (OR 0.5, 95% CI 0.2-0.9, p = 0.03) and FRD sighted within 20 m of garbage sites (OR 0.6, 95% CI 0.4-0.9, p = 0.02) were less likely to be in groups. The number of dogs sighted with an FRD decreased with increased resight-probability of that dog (?= -1.0, p < 0.001). The rural FRD with smaller home-ranges were more likely to be sighted alone (OR 2.3, 95% CI 1.0-95, p = 0.04) than those with larger home-ranges. In the urban site, females (OR 1.3, 95% CI 1.1-1.5, p = 0.002) and older dogs (OR 1.5, 95% CI 1.1-2.1, p = 0.07) were more likely to be found in groups, and groups of dogs were more likely to be seen within 20 meters of garbage sites (OR 1.7, 95% CI 1.5-2.0, p < 0.001). The distribution of urban FRD sighted alone, in pairs, triads, and in packs of ?4 dogs were not random in the administrative (p = 0.02), and the two industrial (p = 0.03 & 0.01) survey tracks of the urban site, implying stable groups. The resighting probability of a dog (? = 0.3, p < 0.0001) and presence of garbage within 20 m (? = 0.2, p < 0.0001) in the urban site increased the likelihood of sighting a FRD with other dogs. It is concluded that data on the resighting probability, presence of garbage points, and home-ranges can be utilised to guide the selection of parenteral or oral rabies vaccination to achieve a population vaccination coverage of 70% to break the transmission cycle of rabies virus in FRD in India.
| S-EPMC6963394 | biostudies-literature