Scaling-up the delivery of dog vaccination campaigns against rabies in Tanzania

Demography of owned dogs across an East African continuum of high-low human density

Understanding the demographics of domestic dogs is essential for effective disease control strategies, particularly in areas where dogs serve as reservoirs of diseases, such as rabies. In this study, conducted in a region proximate to Nairobi, Kenya, we aimed to address the lack of current data on dog demographics. This area spans a high-to-low human density continuum, providing a unique setting for examining the relationship between human and dog populations. We used a household (HH) survey approach, stratifying the area by human population density and selecting sub-locations for every 10th percentile of the population density stratum. Households were randomly selected across strata to estimate the population of owned dogs, which was then extrapolated to the county level. Additionally, a negative binomial regression model was used to analyse the factors influencing the number of dogs owned by households. We found a human-to-owned dog ratio of 3.3:1, indicating an estimated owned dog population of 421,079 (95 % CI: 408,702-424,950) in a county with 1414,022 humans in the last census, with 65 % of the households owning a mean of 2.45 dogs. Multivariable analysis revealed that the presence of a female dog had the strongest association with owning more dogs (OR = 3.08, CI: 2.71-3.50). Wealthier households (OR = 1.67, 95 % CI: 1.12-2.49), those keeping livestock (OR = 1.67, 95 % CI: 1.36-2.02), and larger households (OR = 1.05, 95 % CI: 1.03-1.07) were significantly more likely to own more dogs. These findings suggest that actual human-dog ratios may be higher than estimated in sub-Saharan Africa. Accurate dog demographic data is important for dog-mediated disease and conditions control strategies due to its important logistical and financial implications for implementing targeted control initiatives to improve public health and animal welfare.

Integrated Community-Based Reporting and Field Diagnostics for Improved Rabies Surveillance in Rural Laikipia, Kenya

Rabies vaccination in domestic dog populations has increased globally in a bid to protect human health. Surveillance efforts, however, are inconsistent in endemic regions such as in sub-Saharan Africa, due to fragmented reporting and limited diagnostic capacity for suspected cases, limiting successful monitoring and evaluation of vaccination campaigns. Here, we conducted a pilot study aiming to strengthen rabies surveillance by combining community-based surveillance with field-based diagnostic testing in pastoral and agro-pastoral communities in central Kenya; communities which are frequently marginalised from health systems. During the 6-month pilot study, there were 14 alerts of suspected rabid dogs in the community, of which eight were tested and five diagnostically confirmed as rabid. Two positive samples processed successfully for whole genome sequencing indicated that the rabies variant circulating in central Kenya during the study period belonged to the Africa 1b subclade, which is similar to variants identified in eastern Kenya and Tanzania, suggesting regional transmission. This pilot study indicates that rabies continues to circulate in the region and that community-based surveillance, when combined with enhanced diagnostic testing, can help alleviate underreporting and guide vaccination campaigns.

An Implementation Science Framework to Understand Low Coverage in Mass Dog Rabies Vaccination

Background

Dog-mediated human rabies has been greatly reduced in the Americas and eliminated from most high-income countries. However, many countries in Africa, Asia, and parts of Latin America are still struggling with this gruesome disease. Mass dog vaccination, a One Health strategy, is the primary approach for elimination. However, achieving and sustaining appropriate vaccination coverage in endemic areas remains a challenge. Our objective was to apply the Consolidated Framework for Implementation Research (CFIR) in Arequipa, Peru as a guiding tool to understand the barriers faced by different stakeholders.

Methods

Seven focus groups with 56 participants were conducted to capture community perspectives on rabies and vaccination. A workshop was conducted with two groups of public health personnel (n= 69): mass dog vaccination campaign (MDVC) implementers and authorities, in charge of dog rabies control. With these stakeholders we explored factors contributing to the decrease in MDVC post COVID-19. We used the CFIR approach to understand barriers within five different domains: innovation, outer setting, inner setting, individuals, and implementation.

Findings

Barriers within the community included insufficient communication, a short vaccination schedule, and fragmented collaboration between system coordinators. At the individual level, a decreased perception of rabies risk occurred as both people and their dogs spent more time indoors due to the COVID-19 pandemic (in urban areas). Dog vaccination was deprioritized compared to COVID protection, with individuals focusing on their own vaccinations and avoiding crowded spaces. In peri-urban areas, longer work hours due to the pandemic's financial impact left less time for dog vaccinations on weekends. Participants reported confusion caused by private veterinarians, who claimed that government-subsidized vaccines were of poor quality. Among implementers and authorities, the main barriers included insufficient MDVC materials and equipment, unclear responsibilities, and a lack of time to evaluate the campaign after activities. Importantly, financial constraints and fragmented commitment from higher-level institutions posed challenges for proper planning and implementation.

Conclusions

We identified barriers and co-designed strategies to improve MDVC participation including strengthening municipal alliances, virtual and physical publicity for events within districts, adequate training for vaccinators, reinforcing vaccinators to remain in fixed spots, and expanding vaccination campaign hours.

Rabies vaccinations at the rural-urban divide: successes and barriers to dog rabies vaccination programs from a rural and urban campaign in Zambia

Introduction

Dog vaccination against rabies is considered one of the most effective strategies at preventing human deaths from rabies and is a key strategy for eliminating dog-mediated human rabies deaths. Traditional vaccination approaches in Zambia rarely collect operational data to assess coverage and inform subsequent campaigns.

Methods

Following mass vaccination campaigns in rural (Itezhi tezhi) and urban (Lusaka) communities, we evaluated vaccination coverage achieved during the campaigns and characterized and estimated the dog population in these communities.

Results

Herd immunity (i.e., 70% vaccination coverage) was not achieved in the Lusaka campaign, likely due to challenges in pre-campaign community sensitization and distance to vaccination sites in the central point campaign approach. Dog population density showed a strong exponential association with human density (R2 = 0.89). Extrapolating this relationship nationally, there are an estimated 3.2 million dogs in Zambia (human-to-dog ratio 5.8:1) with 86% residing in rural communities at a very low density of less than 6 dogs per square kilometer.

Discussion

As most dogs were found to reside at very low densities, unique challenges to large-scale dog vaccination approaches may impact Zambia, due to high logistical costs associated with these settings. Prioritizing vaccinations in higher-density free-roaming dog populations could maximize effectiveness in resource-limited settings. Private veterinary services were commonly utilized among surveyed dog owners in urbanized communities in Lusaka, suggesting that they are an important collaborator for achieving rabies herd immunity. With improved knowledge of dog population and ownership characteristics, Zambia is well-prepared to design more effective vaccination campaigns as the rabies elimination program expands.

Reducing spatial heterogeneity in coverage improves the effectiveness of dog vaccination campaigns against rabies

Vaccination programs are the mainstay of control for many infectious diseases. Heterogeneous coverage is hypothesised to reduce vaccination programme effectiveness, but this impact has not been quantified in real systems. We address this gap using fine-scale data from two decades of rabies contact tracing and dog vaccination campaigns in Serengeti district, Tanzania. We also aimed to identify drivers of continued circulation of rabies in the district despite annual vaccination campaigns. Using generalised linear mixed models, we find that current focal (village-level) dog rabies incidence decreases with increasing recent focal vaccination coverage. However, current focal incidence depends most on recent incidence, both focally and in the wider district, consistent with high population connectivity. Removing the masking effects of prior non-focal incidence shows that, for the same average prior non-focal (wider-district) vaccination coverage, increased heterogeneity in coverage among the non-focal villages leads to increased focal incidence. These effects led to outbreaks following years when vaccination campaigns missed many villages, whereas when heterogeneity in coverage was reduced, incidence declined to low levels (<0.4 cases/1,000 dogs annually and no human deaths) and short vaccination lapses thereafter did not lead to resurgence. Through transmission-tree reconstruction, we inferred frequent incursions into the district each year (mean of 7). Inferred incursions substantially increased as a percentage of all cases in recent years, reaching 50% in 2022, suggesting regional connectivity is driving residual transmission. Overall, we empirically demonstrate how population connectivity and spatial heterogeneity in vaccination can impact disease outcomes, highlighting the importance of fine-scale monitoring in managing vaccination programs.

Understanding and overcoming geographical barriers for scaling up dog vaccinations against rabies

Rabies causes 59,000 human deaths annually in over 150 countries. Mass dog vaccination (MDV) is key to controlling dog rabies, requiring 70% coverage in the susceptible dog population to eliminate rabies deaths. MDV campaigns must achieve geographical homogeneity of coverage. Although rabies elimination is feasible, operation challenges exist, especially in hard-to-reach areas. We conducted geospatial modelling to identify geographical factors affecting MDV success in terms of campaign completeness and vaccination coverage across 25 districts in south-eastern Tanzania. From October 2016 to January 2017, about 81,000 dogs were vaccinated in 1,379 (68%) villages within these districts. Multivariable regression analysis revealed that land cover, residence, poverty, and elevation were associated with campaign completeness. The odds of achieving completeness in croplands were 1.75 times higher compared to forests. Vaccination coverage was influenced by residence, area, poverty index, and elevation, with urban areas having lower odds of achieving coverage compared to rural areas. Coverage probabilities exceeding 70% were lower on islands, highlands, urban areas, and areas bordering protected areas. As the 2030 deadline for "zero dog-mediated human rabies deaths" approaches, operational and logistical challenges in MDV campaigns persist. Our data provide insights into MDV success and failure, guiding future control efforts to improve their effectiveness.

Descriptive analyses of knowledge, attitudes, and practices regarding rabies transmission and prevention in rural communities near wildlife reserves in Uganda: a One Health cross-sectional study

BACKGROUND

Despite urban (domestic dog) rabies cycles being the main target for rabies elimination by 2030, sylvatic (wildlife) rabies cycles can act as rabies spillovers especially in settlements contiguous to wildlife reserves. Rural communities next to wildlife reserves are characterized by unique socio-demographic and cultural practices including bat consumption, hunting for bushmeat, and non-vaccination of hunting dogs against rabies among others. This study aimed to compare the knowledge, attitudes, and practices (KAPs) related to rabies transmission and prevention in the three districts of Uganda; (1) Nwoya, neighboring Murchison Falls National Park (MFNP) in the north, (2) Kamwenge neighboring Kibaale National Park (KNP), Queen Elizabeth National Park (QENP) and Katonga Game Reserve (KGR) in the west, and (3) Bukedea, neighboring Pian Upe Game Reserve (PUGR) in the east of Uganda.

METHODS

A community-based cross-sectional survey was conducted in settlements contiguous to these wildlife reserves. Using a semi-structured questionnaire, data were collected from 843 households owning dogs and livestock. Data were collected between the months of January and April 2023. Stratified univariate analyses by district were carried out using the Chi-square test for independence and Fisher's exact test to compare KAPs in the three study districts.

RESULTS

The median age of study participants was 42 years (Q1, Q3 = 30, 52) with males comprising the majority (67%, n = 562). The key findings revealed that participants from the Nwoya district in the north (MFNP) had little knowledge about rabies epidemiology (8.5%, n = 25), only 64% (n = 187) of them knew its signs and symptoms such as a rabid dog presenting with aggressiveness and showed negative attitudes towards prevention measures (15.3%, n = 45). Participants in the Kamwenge district-west (KNP, QENP, and KGR) had little knowledge and negative attitude towards wildlife-human interaction pertaining to rabies transmission and prevention especially those with no or primary level of education (20.9%, n = 27) while participants from Bukedea in the east (PUGR) had remarkedly poor practices towards rabies transmission, prevention, and control (37.8%, n = 114).

CONCLUSIONS

Rabies from sylvatic cycles remains a neglected public health threat in rural communities surrounding national parks and game reserves in Uganda. Our study findings highlight key gaps in knowledge, attitudes, and practices related to rabies transmission and prevention among such communities. Communication and action between veterinary services, wildlife authority, public health teams, social science and community leaders through available community platforms is key in addressing rabies among the sympatric at-risk communities in Uganda.

A Global Perspective on Oral Vaccination of Wildlife against Rabies

The long-term mitigation of human-domestic animal-wildlife conflicts is complex and difficult. Over the last 50 yr, the primary biomedical concepts and actualized collaborative global field applications of oral rabies vaccination to wildlife serve as one dramatic example that revolutionized the field of infectious disease management of free-ranging animals. Oral vaccination of wildlife occurred in diverse locales within Africa, Eurasia, the Middle East, and North America. Although rabies is not a candidate for eradication, over a billion doses of vaccine-laden baits distributed strategically by hand, at baiting stations, or via aircraft, resulted in widespread disease prevention, control, or local disease elimination among mesocarnivores. Pure, potent, safe, and efficacious vaccines consisted of either modified-live, highly attenuated, or recombinant viruses contained within attractive, edible baits. Since the late 1970s, major free-ranging target species have included coyotes (Canis latrans), foxes (Urocyon cinereoargenteus; Vulpes vulpes), jackals (Canis aureus; Lupulella mesomelas), raccoons (Procyon lotor), raccoon dogs (Nyctereutes procyonoides), and skunks (Mephitis mephitis). Operational progress has occurred in all but the latter species. Programmatic evaluations of oral rabies vaccination success have included: demonstration of biomarkers incorporated within vaccine-laden baits in target species as representative of bait contact; serological measurement of the induction of specific rabies virus neutralizing antibodies, indicative of an immune response to vaccine; and most importantly, the decreasing detection of rabies virus antigens in the brains of collected animals via enhanced laboratory-based surveillance, as evidence of management impact. Although often conceived mistakenly as a panacea, such cost-effective technology applied to free-ranging wildlife represents a real-world, One Health application benefiting agriculture, conservation biology, and public health. Based upon lessons learned with oral rabies vaccination of mesocarnivores, opportunities for future extension to other taxa and additional diseases will have far-reaching, transdisciplinary benefits.

Dog ecology and rabies knowledge, attitude and practice (KAP) in the Northern Communal Areas of Namibia

In 2021, a comprehensive dog demographic questionnaire combined with a KAP survey were conducted in the northern communal areas (NCAs) of Namibia with the aim of gaining a better understanding of dog populations, owner behaviour, and knowledge, attitudes and practices (KAP) relating to rabies. The survey of 3,726 households across the eight regions of the NCAs provided insights that will inform interventions in order to improve human rabies prevention and Namibia's dog rabies control strategy. The results showed a relatively low average human/dog ratio (HDR) of 5.4:1 indicating a surprisingly high dog population of at least 272,000 dogs in the NCAs, 93% of which appear to be owned but are free-roaming. Data analysis revealed opportunities but also highlighted needs for improvements in rabies surveillance and mass dog vaccinations. Although knowledge, attitude, and practice scores towards epidemiologic and clinical aspects, human rabies prevention, and dog rabies vaccination were deemed to be acceptable, the survey nevertheless revealed deficiencies in certain aspects in some of the population. Interestingly, data seemed to indicate relatively high dog bite incidences per 100,000 people, ranging between 262 and 1,369 and a certain number of unreported human rabies cases. Despite the very high number of dogs, only 50% of dog-owning households reported having vaccinated their dogs. In order to address these issues, the planning, announcement, and implementation of mass dog vaccination campaigns needs to be adapted to achieve adequate vaccination coverage. Another focus needs to be on rabies awareness and education if Namibia is to be significantly contributing to the global goal of "Zero by 30".

The Use of Dog Collars Offers Significant Benefits to Rabies Vaccination Campaigns: The Case of Zanzibar, Tanzania

Tools and resources that could increase dog vaccination coverage have become increasingly critical towards progressing the goal to eliminate dog-mediated human rabies by 2030. In this regard, dog collars that are fitted during vaccination campaigns could potentially enhance owner participation. The use of dog collars will, however, increase the cost per dog vaccinated and the impact and benefit of this practice should be elucidated. This study evaluated the impact of dog collars by testing the perception and related behavioural influences in communities in Zanzibar. In this cross-sectional investigation-conducted approximately two months after the implementation of a mass dog vaccination (MDV) where dog collars were provided to vaccinated dogs-data were collected from 600 respondents in 56 municipal wards in Zanzibar. Descriptive analyses and logistic regressions were undertaken to determine the impact the collars had on respondents with regards to (i) engaging with the community dogs, (ii) health seeking behaviour after exposure, and (iii) overall participation during dog vaccination campaigns. From the data, it was evident that the collars had a positive impact on the community's perception of dogs, with 57% of the respondents feeling safer around a dog with a collar, while 66% of the respondents felt less safe around a dog without a collar. Furthermore, the collars had a positive impact on participation during dog vaccination campaigns. Of the 142 respondents who owned dogs, 64% reported that the collars made them more likely to take their dogs for vaccination, and 95% felt that the collar was an important sign of the dog's vaccination status. This study demonstrated that dog collars could not only improve participation during dog vaccination campaigns, but that they could also play a significant role in the community's perception of rabies vaccination campaigns and vaccinated dogs in general.

Emergency response using oral rabies vaccination of dogs -field data from Namibia demonstrate high efficiency

Dog-mediated rabies is responsible for tens of thousands of human deaths annually, and in resource-constrained settings, vaccinating dogs to control the disease at source remains challenging for various reasons. Currently, rabies elimination efforts rely on mass dog vaccination by the parenteral route. While oral rabies vaccination (ORV) of dogs is primarily considered a tool to increase herd immunity, particularly by targeting free-roaming and stray dogs, here, we are showcasing an ORV-only approach as an emergency response model. Using a third-generation vaccine and a standardized egg-flavored bait, we assessed the effectiveness and vaccination under field conditions in the Zambezi region of Namibia. During this trial, with four teams and within four working days, 3097 dogs were offered a bait, of which 88,0% were considered vaccinated. Teams managed to vaccinate, on average, over 20 dogs/h, despite using a door-to-door vaccination approach. The favorable results both in terms of bait acceptance and successful vaccination as well as field applicability and effectiveness further support the great potential of ORV in dog rabies control programmes.

Participation in mass dog vaccination campaigns in Tanzania: Benefits of community engagement

Background

Canine rabies causes about 59,000 human deaths each year globally but the disease can be eliminated by sustaining sufficient dog vaccination coverage over several consecutive years. A challenge to achieving high coverage is low participation of dog owners in vaccination campaigns. We explored whether and how previously identified contributory factors to low participation can be addressed through community engagement activities.

Methods

We engaged communities in two wards in Tanzania on dog behavior and handling, safe ways of interacting with dogs, and their perceptions of dog vaccination. We shared and elicited information from them through village meetings, video screenings, posters and leaflets and involved the leadership of one of the wards in planning and implementing a dog vaccination exercise to explore the feasibility of their participation. We assessed the impact of engagement activities with household surveys, meeting reports, observations and focus group discussions. We used a generalized linear mixed-effects model to identify predictors of knowledge and perceptions and compared knowledge amongst respondents before and after engagement activities. Qualitative data was analyzed inductively to explore perceptions of dog handling and vaccination and feasibility, opportunities and barriers to community leadership participation in organizing mass dog vaccination.

Main findings

Knowledge of dog behavior, dog handling, and safe ways of interacting with dogs was positively associated with age (p < 0.0001), dog ownership (p = 0.0203), training (p = 0.0010) and previous experience of a dog bite (p = 0.0002); and was negatively associated with being afraid of dogs (p = 0.0061) and participation in a recent dog vaccination campaign (p = 0.0077). Knowledge was low before and significantly improved after engagement activities. The majority (92%) of respondents believed dog vaccination has no negative effects on dogs. Respondents perceived lack of bonding with their dog as a limitation to the ability to restrain a dog for vaccination. The community performed most roles assigned to them in the dog vaccination exercise, but barriers such as lack of motivation for volunteering exist.

Conclusion

Engaging communities regularly on dog vaccination can improve their knowledge of dog behavior and dog handling techniques, and may help improve owner participation in dog vaccination campaigns.

Oral rabies vaccination of dogs-Experiences from a field trial in Namibia

Dog-mediated rabies is responsible for tens of thousands of human deaths annually, and in resource-constrained settings, vaccinating dogs to control the disease at source remains challenging. Currently, rabies elimination efforts rely on mass dog vaccination by the parenteral route. To increase the herd immunity, free-roaming and stray dogs need to be specifically addressed in the vaccination campaigns, with oral rabies vaccination (ORV) of dogs being a possible solution. Using a third-generation vaccine and a standardized egg-flavoured bait, bait uptake and vaccination was assessed under field conditions in Namibia. During this trial, both veterinary staff as well as dog owners expressed their appreciation to this approach of vaccination. Of 1,115 dogs offered a bait, 90% (n = 1,006, 95%CI:91-94) consumed the bait and 72.9% (n = 813, 95%CI:70.2-75.4) of dogs were assessed as being vaccinated by direct observation, while for 11.7% (n = 130, 95%CI:9.9-17.7) the status was recorded as "unkown" and 15.4% (n = 172, 95%CI: 13.4-17.7) were considered as being not vaccinated. Smaller dogs and dogs offered a bait with multiple other dogs had significantly higher vaccination rates, while other factors, e.g. sex, confinement status and time had no influence. The favorable results of this first large-scale field trial further support the strategic integration of ORV into dog rabies control programmes. Given the acceptance of the egg-flavored bait under various settings worldwide, ORV of dogs could become a game-changer in countries, where control strategies using parenteral vaccination alone failed to reach sufficient vaccination coverage in the dog population.