Fox Rabies Research Articles

Rabies surveillance in the United States during 2022.

To provide comprehensive epidemiological information about the distribution and occurrence of rabies during 2022 in the US, Canada, and Mexico. The US National Rabies Surveillance System collected 2022 animal rabies data from US state and territorial public health departments and USDA Wildlife Services. Temporal and geographic analyses were conducted to evaluate trends in animal rabies cases. During 2022, 54 US jurisdictions reported 3,579 animal rabies cases, reflecting a 2.3% decline from 3,663 cases reported in 2021. Six states collectively reported > 50% of animal rabies cases: Texas (395 [11.0%]), Virginia (337 [9.4%]), Pennsylvania (329 [9.2%]), New York (267 [7.5%]), North Carolina (264 [7.4%]), and California (241 [6.7%]). Out of the total reported rabies animal cases, 3,234 (90.4%) were attributed to wildlife, with bats (1,218 [34.0%]), raccoons (1,014 [28.3%]), skunks (660 [18.4%]), and foxes (269 [7.5%]) representing the primary hosts confirmed with rabies. Rabid cats (222 [6.2%]), cattle (42 [1.2%]), and dogs (50 [1.4%]) constituted > 90% of reported domestic animal rabies cases. In 2022, there was an increase in the number of animal samples submitted for rabies testing in the US and Canada. A notable geographic expansion of gray fox rabies virus variant was detected in the US. Three human rabies deaths due to vampire bat rabies infection occurred in Mexico; none were reported from the US and Canada. Laboratory diagnosis of rabies in animals is critical to ensure judicious use of human rabies postexposure prophylaxis.

Spatial Clustering of Rabies by Animal Species in New Jersey, United States, from 1989 to 2023.

Identifying spatial clusters of rabies in animals aids policymakers in allocating resources for rabies prevention and control. This study aimed to investigate spatial patterns and hotspots of rabies in different animal species at the county level in New Jersey. Data on animal rabies cases from January 1989 to December 2023 were obtained from the New Jersey Department of Health and aggregated by county. Global Moran's index (I) statistics were computed for each species to detect global spatial clustering (GeoDa version 1.22). Local Moran's indicators of spatial association (LISA) were computed to identify local clusters of rabies. The results from the LISA analysis were mapped using ArcGIS Pro to pinpoint cluster locations. A total of 9637 rabies cases were analyzed among raccoons (n = 6308), skunks (n = 1225), bats (n = 1072), cats (n = 597), foxes (n = 225), and groundhogs (n = 210). A global Moran's test indicated significant global spatial clustering in raccoons (I = 0.32, p = 0.012), foxes (I = 0.29, p = 0.011), and groundhogs (I = 0.37, p = 0.005). The LISA results revealed significant spatial clustering of rabies in raccoons and foxes in southeastern New Jersey and in groundhogs in northern New Jersey. These findings could guide the development of targeted oral rabies vaccination programs in high-risk New Jersey counties, reducing rabies exposure among domestic animals and humans.

Oral rabies vaccination of foxes in Türkiye, 2019–2022

BackgroundRabies in Turkey is maintained by dogs, but following a sustained spill-over, red fox mediated rabies had spread from the Aegean region to the central part of Türkiye. During the past four years from 2019 to 2023 large scale efforts used oral rabies vaccination (ORV) to control rabies in red foxes. Here, we present the results of the largest ORV campaign on the Asian continent. MethodsORV campaigns were carried out twice a year in spring and autumn with a targeted bait density of 20–23 baits/km2. Monitoring of ORV campaigns included the GIS-based analyses of bait distribution, the assessment of bait uptake through biomarker detection and the determination of seroconversion (sero-positivity in ELISA) in the target species collected within the vaccination area. For determination of fox rabies incidence in vaccination areas as the main indicator of the performance of the ORV campaigns, epidemiological data was obtained from the national passive surveillance program. ResultsAerial bait distribution was highly accurate, with >99 % of baits being recorded from targeted zones, thus meeting the desired bait densities. Although the overall bait uptake (28.1 %; 95 %CI: 23.2–32.8) and seroprevalance (36.3 %; 95 %CI: 30.0–43.2) were low, rabies incidence drastically decreased in ORV areas and rabies was eliminated from western and central parts of Turkey, with no reported cases in foxes from ORV areas in 2022 and 2023. ConclusionsA large-scale ORV campaign against fox rabies using high quality vaccine baits and the GIS-aided and monitored bait distribution was able to control fox mediated rabies in the western and central parts of Türkiye. Rabies control both in dogs and foxes should be expanded to cover also the eastern parts of Türkiye, to become eventually rabies free.

Impact of spatial and temporal resource distribution on rabies dynamics in the Arctic

In the Arctic, rabies is endemic in the Arctic fox (Vulpes lagopus), posing a significant and ongoing health risk for people and domestic animals. The mechanisms by which rabies is maintained within the low-density fox populations in the Arctic remain unclear. In this study, we developed a spatially explicit individual-based stochastic epidemiological model and performed an uncertainty analysis to better understand Arctic fox rabies dynamics. Rabies persisted in 25.68% of model simulations, with several variables having significant impact on rabies persistence: probability of rabies transmission, spatial and temporal distribution food resources, mean litter size and variability of rabies incubation periods. Where rabies is endemic, we identified 5 key parameters for rabies dynamics: spatiotemporal resource distribution, probability of birth for adult females, mean and standard deviation of litter size, and incubation period of rabies. Our study demonstrates that Arctic rabies can persist in its primary host under conditions consistent with existing empirical data in the literature and showed the important role played by the spatial and temporal distribution of resources. Finally, our results suggest that the ecological impacts of rapid climate warming could decrease the overall persistence of rabies in the Arctic and the associated health risk in Arctic communities.

Low levels of genetic differentiation and structure in red fox populations in Eastern Canada and implications for Arctic fox rabies propagation potential.

Rabies is a lethal zoonosis present in most parts of the world which can be transmitted to humans through the bite from an infected mammalian reservoir host. The Arctic rabies virus variant (ARVV) persists mainly in populations of Arctic foxes (Vulpes lagopus), and to a lesser extent in red fox populations (Vulpes vulpes). Red foxes are thought to be responsible for sporadic southward movement waves of the ARVV outside the enzootic area of northern Canada. In this study, we wanted to investigate whether red foxes displayed notable levels of genetic structure across the Quebec-Labrador Peninsula, which includes portions of the provinces of Quebec and Newfoundland-Labrador in Canada, and is a region with a history of southward ARVV movement waves. We combined two datasets that were collected and genotyped using different protocols, totalling 675 red fox individuals across the whole region and genotyped across 13 microsatellite markers. We found two genetic clusters across the region, reflecting a latitudinal gradient, and characterized by low genetic differentiation. We also observed weak but significant isolation by distance, which seems to be marginally more important for females than for males. These findings suggest a general lack of resistance to movement in red fox populations across the Quebec-Labrador Peninsula, regardless of sex. Implications of these findings include additional support for the hypothesis of long-distance southward ARVV propagation through its red fox reservoir host.

Fifty years of spring censuses in black grouse (Lyrurus tetrix) in the High Fens (Belgium): did the rabies vaccination has a negative impact on a fox prey population?

The online version contains supplementary material available at 10.1007/s10344-023-01642-w.

Occurrence and Risk Factors of Dog Bites in Northern Indigenous Communities: A Scoping Review.

The relationship between northern Indigenous people and dogs has evolved over the past years alongside events such as colonization, settlement, proliferation of snowmobiling and other socio-cultural and environmental changes. These changes have had negative impacts on this relationship, and with the endemic presence of arctic fox rabies, dog bites have become an important public health burden. The objective of this study was to synthesize the state of knowledge regarding the occurrence of dog bites and associated risk factors in the specific context of northern Indigenous communities. A scoping review was conducted in seven bibliographic databases, from June 2018 to May 2020. From this search, 257 original studies were identified and eight papers were included for final analysis. Annual occurrence of dog bites in northern Indigenous communities ranged from 0.61 to 59.6/10,000 inhabitants. Dog bites affected 27–62.9% of the population in those regions during their lifetime. Very few studies compared the occurrence of dog bites between people living in northern communities with other populations or settings, but available evidence suggests that Indigenous people living in northern communities are at higher risk of dog bites than the rest of the population. Several individual and environmental risk factors were identified in the selected studies, although the strength of evidence varied significantly. Age (children) and gender (male) were well documented individual risk factors. Other factors, such as organizational barriers to dog management and lack of access to veterinary services, were identified and discussed by several authors. The results of this study support concerns about the higher risk of bites in northern Indigenous communities, and underscore the urgent need for more research into the contextual and environmental factors that impact the mitigation of these risks.

Diversity of rabies virus detected in Inner Mongolia, China, 2019-2021.

Rabies is a serious public health issue in China, with over 95% of human infections transmitted by dogs. As part of a routine surveillance carried out in the Inner Mongolia Autonomous Region (IMAR) between 2019 and 2021, 80 of 95 suspected rabies cases in domestic animals (dogs, livestock) and wild carnivores (foxes, badgers, a raccoon dog) were confirmed as rabies virus (RABV) positive. Phylogenetic analysis of RABVs of the 80 cases based on complete N genes showed that 97.5% (78/80) of the virus strains belonged to the Cosmopolitan (steppe-type) clade, with one in each of Arctic-related (AL2) and Asian (SEA1) clades. The data show that infected foxes have become a major transmission source of rabies in China, second only to dogs, and play a pivotal role in animal rabies epizootics in the north and northwest of the country. The recent spread of fox rabies to other animal species presents an increasing threat to public health and emphasizes the importance of animal rabies surveillance.

История борьбы с бешенством в Украине со времен Пастера до наших дней

Бешенство остается древнейшим вирусным зоонозным заболеванием, которое всегда заканчивается летально и которое в наши дни широко распространено по всему миру и ежегодно вызывает смерть около 60 тысяч человек. Поскольку борьба с ликвидацией гидрофобии в Украине ведется уже более 135 лет, нашей целью было напомнить о проблемах и успехах оказания антирабической помощи в разные периоды эпизоотического процесса в прошлом веке, напомнить основные специфические особенности заражения и показать реальные проблемы в наши дни. Материалами для анализа были архивные данные из сводных отчетов областных СЭС, Института эпидемиологии и инфекционных заболеваний имени Л.В. Громашевского, лаборатории нейроинфекций ИВМ НААН Украины, а также отчеты областных администраций ветеринарной медицины Госпродпотребслужбы Украины. Было показано, что пики эпизоотий наблюдались в определенные исторические периоды. Во время первого периода, городского бешенства (собак), свою эффективность показали массовые вакцинации собак в комплексе с жесткой регуляцией численности бездомных животных. Второй период, связанный с лисьим бешенством, продолжался 30 лет, из которых почти 20 лет были относительно благополучными, чему способствовало строжайшее соблюдение во всех областях Украины мер по регуляции численности лисиц. В начале XXI века резко повысилась напряженность эпизоотического процесса. При этом во всех областях численность лисиц уже не поддерживалась на безопасном уровне, и их заболеваемость увеличилась почти в 20 раз. Начатая в 2001 году пероральная вакцинация до настоящего времени проводится не в полном объеме. Вакцинация домашних плотоядных животных также не достигает необходимого уровня покрытия 70 % популяции. Пытаются прививать и бездомных животных, хотя уже давно доказано, что в период постоянных стрессов и переохлаждения вакцина не вызывает выработку иммунитета до защитного уровня. Таким образом, в настоящее время главную проблему при обращении за антирабической помощью составляют собаки. Так, в 2019 году за помощью по поводу укуса собакой обратились 51 232 человека. В целом в 2019 году за антирабической помощью обратились 73 962 человека, прививки были назначены 21 980 лицам. С тяжелыми укусами отмечалось 4039 человек, из них 1161 человек были укушены больным животным с подтвержденным диагнозом и 777 человек были укушены дикими животными (то есть 1938 человек были спасены от смерти), а 16 113 лицам, получившим легкие укусы (73,3 % от числа привитых), было дано 10 дней для выяснения опасности укуса, но сделать это не удалось, так как укусившее животное убежало. За счет этой категории пострадавших количество привитых резко увеличивается. Важно отметить, что каждый укус бродячей собакой для пострадавшего — испытание, а курс антирабических прививок стоит около 6 тыс. грн в зависимости от тяжести укуса, поэтому открытым остается вопрос о регуляции численности бездомных собак и целесообразности их вакцинации.

Atto-Foxes and Other Minutiae

This paper addresses the problem of extinction in continuous models of population dynamics associated with small numbers of individuals. We begin with an extended discussion of extinction in the particular case of a stochastic logistic model, and how it relates to the corresponding continuous model. Two examples of ‘small number dynamics’ are then considered. The first is what Mollison calls the ‘atto-fox’ problem (in a model of fox rabies), referring to the problematic theoretical occurrence of a predicted rabid fox density of 10^{-18} (atto-) per square kilometre. The second is how the production of large numbers of eggs by an individual can reliably lead to the eventual survival of a handful of adults, as it would seem that extinction then becomes a likely possibility. We describe the occurrence of the atto-fox problem in other contexts, such as the microbial ‘yocto-cell’ problem, and we suggest that the modelling resolution is to allow for the existence of a reservoir for the extinctively challenged individuals. This is functionally similar to the concept of a ‘refuge’ in predator–prey systems and represents a state for the individuals in which they are immune from destruction. For what I call the ‘frogspawn’ problem, where only a few individuals survive to adulthood from a large number of eggs, we provide a simple explanation based on a Holling type 3 response and elaborate it by means of a suitable nonlinear age-structured model.

Features of the Spatial Spread of Rabies in the Conditions of Mountain RELIEFS of South Siberia (Republic of Altai)

Relevance.The experience of combating rabies in Europe has shown that the tactics of preventive measures in mountains must be modified. At the beginning of the 21st century, the spread of fox rabies into the previously rabies-free mountain areas in southern Siberia was noted.The aimis to trace the spread of rabies in the Altai Mountains after the introduction of the virus.Materials and methods.A retrospective descriptive study using GIS was carried out. For mapping, information on 55 laboratory confirmed cases of rabies in the Altai Republic, QGIS 3.16.0, ArcMap 10.8.1, ArcScene 10.8.1 programs and an electronic landscape-geographical maps "Natural Earth" and "Open street map" were used. The spatial-temporal distribution of rabies was compared with changes in postexposure prophylaxis (PEP).Results.In 2007, rabies was detected for the first time since 1948 in the Altai Mountains. Wild animals (fox, wolf, badger) accounted for 52.7% (95% CI 39.5–65.9). Most of the cases were found in the foothills and river valleys at an altitude of less than 1,000 meters above sea level and only 16.4% (0.0–26.2) – in areas with heights from 1,000 to 2,000 m. Rabies was not recorded in the mountains above 2,000 m. Two different directions of the virus introduction are assumed: from the forest-steppe plains of the Altai Territory (Russia) and from the mountainous steppes of Mongolia. In 2007–2019 the annual number of patients seeking medical attention after animal bites increased by 86%. A correlation between the animal case number in different areas and the average annual PEP was noted (r = 0.649, p = 0.03). 4.Conclusions.Features of the fox rabies spread in the Altai Mountains allows to use the experience of fighting this disease in the mountainous regions of Central Europe.

Relationships between fox populations and rabies virus spread in northern Canada.

Rabies spreads in both Arctic (Vulpes lagopus) and red foxes (Vulpes vulpes) throughout the Canadian Arctic but limited wildlife disease surveillance, due to the extensive landmass of the Canadian north and its small widely scattered human population, undermines our knowledge of disease transmission patterns. This study has explored genetic population structure in both the rabies virus and its fox hosts to better understand factors that impact rabies spread. Phylogenetic analysis of 278 samples of the Arctic lineage of rabies virus recovered over 40 years identified four sub-lineages, A1 to A4. The A1 lineage has been restricted to southern regions of the Canadian province of Ontario. The A2 lineage, which predominates in Siberia, has also spread to northern Alaska while the A4 lineage was recovered from southern Alaska only. The A3 sub-lineage, which was also found in northern Alaska, has been responsible for virtually all cases across northern Canada and Greenland, where it further differentiated into 18 groups which have systematically evolved from a common predecessor since 1975. In areas of Arctic and red fox sympatry, viral groups appear to circulate in both hosts, but both mitochondrial DNA control region sequences and 9-locus microsatellite genotypes revealed contrasting phylogeographic patterns for the two fox species. Among 157 Arctic foxes, 33 mitochondrial control region haplotypes were identified but little genetic structure differentiating localities was detected. Among 162 red foxes, 18 control region haplotypes delineated three groups which discriminated among the Churchill region of Manitoba, northern Quebec and Labrador populations, and the coastal Labrador locality of Cartwright. Microsatellite analyses demonstrated some genetic heterogeneity among sampling localities of Arctic foxes but no obvious pattern, while two or three clusters of red foxes suggested some admixture between the Churchill and Quebec-Labrador regions but uniqueness of the Cartwright group. The limited population structure of Arctic foxes is consistent with the rapid spread of rabies virus subtypes throughout the north, while red fox population substructure suggests that disease spread in this host moves most readily down certain independent corridors such as the northeastern coast of Canada and the central interior. Interestingly the evidence suggests that these red fox populations have limited capacity to maintain the virus over the long term, but they may contribute to viral persistence in areas of red and Arctic fox sympatry.

Epidemiology of Animal Rabies - China, 2010-2020.

IntroductionRabies is a fatal zoonotic infectious disease that poses a serious threat to public health in China. Since 2005, a National Animal Rabies Surveillance System has been operating to understand the rabies situation in animals in China with a view to control and eventually eliminate dog-mediated human rabies.MethodsFrom 2010, the brain tissues of dogs, livestock, and wild animals showing rabies-like clinical signs were collected and tested by the National Reference Laboratory (NRL) for Animal Rabies to analyze the epidemiological characteristics of rabies, including animal species, geographic distribution, and transmission sources. Over the same period, clinically suspected animal rabies cases were collected by Animal Disease Control Centers through the National Animal Disease Monitoring Information Platform (NADMIP) and then reported in the Veterinary Bulletin. ResultsDuring 2010–2020, 170 of 212 suspected animal rabies cases were submitted to and confirmed by NRL as rabies virus-positive. Of these confirmed cases dogs, especially free-roaming and ownerless dogs in rural areas, were major transmission hosts (71/170). A total of 51 infected dogs attacked humans with 45 biting more than one person. The dog cases were reported all year round, but with significantly more in spring and summer. The majority of livestock rabies cases (70/80) being caused by rabid wild foxes in Xinjiang and Inner Mongolia revealed that foxes play a pivotal role in animal rabies epizootics in the north and northwest of the country.ConclusionDogs were the main transmission sources of rabies in China, and along with the recent increase of rabies in foxes and other wildlife, presented an increasing threat to livestock and public health.

Prioritisation of areas for early detection of southward movement of arctic fox rabies based on historical surveillance data in Quebec, Canada.

Arctic rabies virus variant (ARVV) is enzootic in Quebec (Canada) north of the 55th parallel. With climate change, increased risk of re-incursion of ARVV in more densely populated southern regions raises public and animal health concerns. The objective of this study was to prioritise geographical areas to target for an early detection of ARVV incursion south of the 55th parallel based on the historical spatio-temporal trends of reported rabies in foxes in Quebec. Descriptive analyses of fox rabies cases from 1953 to 2017 were conducted. Three periods show increases in the number of fox rabies cases in southern regions and indicate incursion from northern areas or neighbouring provinces. The available data, particularly in central and northern regions of the province, were scarce and of low spatial resolution, making it impossible to identify the path of spread with precision. Hence, we investigated the use of multiple criteria, such as historical rabies cases, human population density and red fox (Vulpes vulpes) relative abundance, to prioritise areas for enhanced surveillance. This study underscores the need to define and maintain new criteria for selecting samples to be analysed in order to detect rapidly ARVV cases outside the current enzootic area and any potential re-incursion of the virus into central and southern regions of the province.

Retrospective Evaluation of Implementation of Long-Term Forecast on Spatial Spread of Rabies in the Asian Part of Russia

Objective:To evaluate the historical long-term forecast of the spatial spread of rabies in Siberia and Far East and to characterize modern approaches to spatial forecasting. The concept of spatial spread of rabies in the Asian part of Russia, developed in the 80s of the twentieth century, is subjected to critical analysis based on information on rabies registration for 1881–1980 and zoogeographic data. At that time, 5 rabies enzootic regions were identified, and the most probable directions of further exportation of infection suggested. At first, a review of published data on human and animal rabies cases for the period of 1985–2019 was undertaken (including reference publications). Data on cases of rabies among humans and animals were selected for which geographical coordinates could be determined. Mapping was performed using GIS (QGIS 3.12.0 software and “Natural Earth” and “OpenStreetMap” electronic maps). Comparison of maps for different time periods demonstrated that rabies incidence was recorded mainly within the previously identified risk areas. However, the occurrence of human disease in different regions did not always correspond to the intensity of epizootics and the predicted risk. Next, in an attempt to correct the prognosis of the spatiotemporal rabies spread, we reviewed publications that incorporated virus genetic data along with GIS technology and modeling application. The distribution of the three major rabies virus lineages (“steppe”, “Arctiс-like”, “Arctic”) corresponded to the regions that were previously identified. The spread of fox rabies (the “steppe” rabies virus lineage) in the north-east direction was described. In several instances, rabies outbreaks in southern Siberia and Far East were associated with cross-border movement of the virus from Kazakhstan, Mongolia and China. Data on the speed of the epizootic waves, pathways, and natural barriers for virus spread are discussed. The correction of the forecast for rabies virus circulation and spread is important for the development of control strategies in the region, including oral vaccination of wildlife virus reservoirs.

Fox rabies outbreaks in the republic of Buryatia: Connections with neighbouring areas of Russia, Mongolia and China.

The Republic of Buryatia (RB) is located southeast of Lake Baikal and shares a long border with Mongolia. This region of Russia was rabies-free from 1982 to 2010. The first outbreak of fox rabies in RB was identified in 2011, about 30km from the Russian-Mongolian border. We assessed the possible pathways to further spread the 'steppe' phylogenetic lineage of the rabies virus near the northeastern limits of its known distribution. All rabies cases were located 30-210km north of the Russia-Mongolia border, with a distance of up to 320km from each other. Rabies has spread to the north across steppe landscapes and river valleys, with foxes being the main natural hosts of the infection. All RABV isolates from RB belong to the 'steppe' phylogenetic lineage, and three major phylogenic groups could be separated. Group 1 contains sequences from RB, Mongolia, China (Inner Mongolia), and bordering regions of Russia. Group 2 is formed by isolates from other regions of Eastern Siberia, which have no borders with RB and foreign countries. Group 3 contains samples from Western Siberia with endemic fox rabies since the 1950s. The most probable cause of fox rabies epizooty in the RB was multiple drift of the RABV across the Russian-Mongolian border. Our data show that after 2010, fox rabies affected new areas in Central Asia and extended to the north and northeast. Affected areas are similar to the Mongolian-type steppes in their zoogeographical aspect. Closely related genetic lineages of RABV are circulating in RB, Mongolia and the nearest areas of China. International cooperation is necessary to prevent the spread of rabies in the bordering territories of these countries.

Local rabies transmission and regional spatial coupling in European foxes.

Infectious diseases are often transmitted through local interactions. Yet, both surveillance and control measures are implemented within administrative units. Capturing local transmission processes and spatial coupling between regions from aggregate level data is therefore a technical challenge that can shed light on both theoretical questions and practical decisions. Fox rabies has been eliminated from much of Europe through oral rabies vaccination (ORV) programmes. The European Union (EU) co-finances ORV to maintain rabies freedom in EU member and border states via a cordon sanitaire. Models to capture local transmission dynamics and spatial coupling have immediate application to the planning of these ORV campaigns and to other parts of the world considering oral vaccination. We fitted a hierarchical Bayesian state-space model to data on three decades of fox rabies cases and ORV campaigns from Eastern Germany. Specifically, we find that (i) combining regional spatial coupling and heterogeneous local transmission allows us to capture regional rabies dynamics; (ii) incursions from other regions account for less than 1% of cases, but allow for re-emergence of disease; (iii) herd immunity achieved through bi-annual vaccination campaigns is short-lived due to population turnover. Together, these findings highlight the need for regular and sustained vaccination efforts and our modelling approach can be used to provide strategic guidance for ORV delivery. Moreover, we show that biological understanding can be gained from inference from partially observed data on wildlife disease.

Wildlife and Bait Density Monitoring to Describe the Effectiveness of a Rabies Vaccination Program in Foxes.

Fox rabies has been eliminated from vast areas of West and Central Europe, but cases still occur in the Balkans. Oral vaccination is an effective method for reducing the incidence of the disease in wildlife, but it requires monitoring if bait density is adequate for the density of the wildlife reservoir. We developed a methodology to evaluate the effectiveness of aerial vaccination campaigns conducted in Montenegro during autumn 2011 and spring 2012. The effectiveness of the vaccination campaign was assessed by (i) estimating the density of baits, (ii) estimating the distribution of the red fox, (iii) identifying critical areas of insufficient bait density by combining both variables. Although the two vaccination campaigns resulted in 45% and 47% of the country’s total area not reaching recommended density of 20 baits/km2, the consecutive delivery of both campaigns reduced these “gaps” to 6%. By combining bait and reservoir density data, we were able to show that bait density was lower than fox density in only 5% of Montenegro’s territory. The methodology described can be used for real-time evaluation of aerial vaccine delivery campaigns, to identify areas with insufficient bait densities.

A model for spatial spreading and dynamics of fox rabies on a growing domain

A model for spatial spreading and dynamics of fox rabies on a growing domain

Spreading speeds of rabies with territorial and diffusing rabid foxes

A mathematical model is formulated for the fox rabies epidemic that swept through large areas of Europe during parts of the last century. Differently from other models, both territorial and diffusing rabid foxes are included, which leads to a system of partial differential, functional differential and differential-integral equations. The system is reduced to a scalar Volterra-Hammerstein integral equation to which the theory of spreading speeds pioneered by Aronson and Weinberger is applied. The spreading speed is given by an implicit formula which involves the space-time Laplace transform of the integral kernel. This formula can be exploited to find the dependence of the spreading speed on the model ingredients, in particular on those describing the interplay between diffusing and territorial rabid foxes and on the distribution of the latent period.