Domestic dogs in a fragmented landscape in the Brazilian Atlantic Forest: abundance, habitat use and caring by owners

Human presence as a determinant of the occurrence of mammals in a high diversity protected area of Cerrado-Caatinga ecotone in Brazil

The Cerrado domain and its biodiversity has suffered several anthropogenic influences. Our objective was to evaluate the influence of biotic and anthropic variables on the mammal community in a protected area in the Cerrado-Caatinga ecotone. For this we sampled the mammals using camera traps (4,072 days/trap) for 16 months. We used generalized mixed linear models (GLMM) with model selection via Akaike's Information Criteria corrected for small sample size (AICc) to assess the influence of variables on richness, abundance and functional groups of mammals. We made a total of 663 photographic records of 16 species of medium and large mammals. The richness and number of mammals was negatively influenced by the distance to human settlements while carnivores were not affected by any of the variables evaluated, herbivores and generalists were more common in areas closer from human habitation. Despite the presence of large areas of native vegetation, our results show that there is a dominance of common and generalist species. The protected area is vulnerable to different sources of human pressure and the design and implementation of a management plan can be a key tool for protecting biodiversity and regulating the use of natural resources by local communities.

The impacts of domestic dogs (Canis familiaris) on wildlife in two Brazilian hotspots and implications for conservation

Exotic species are major threats to biodiversity worldwide. Domestic dogs (Canis familiaris) are among the most common invasive predators in the world, interacting with wildlife in many ways. We present ecological data based on camera traps and occasional observations of free–roaming domestic dogs from localities within the Brazilian Atlantic forest and Cerrado hotspots. Canis familiaris was the second most abundant mammal species, and the most abundant carnivore. Dogs chased, killed, and/or competed with at least 26 native species. They consumed none of the killed animals, which together with the predominant records of solitary individuals acting during the daytime indicates they are mainly free–roaming dogs relying on humans for food and shelter. The high numbers of dogs and the wide range of prey suggest wildlife could be greatly impacted by domestic dogs, especially in areas that are highly threatened by anthropogenic activities, such as biodiversity hotspots. We highlight possible measures (such as the eradication or removal of dogs from natural areas) that could help to reduce the environmental damage caused by domestic dogs in the region.

Implications of domestic dogs in the epidemiology of Rickettsia parkeri strain Atlantic rainforest and Rangelia vitalii in Southeastern Brazil

This study aimed to evaluate the occurrence of diseases transmitted by Amblyomma ovale in 61 dogs monitored for three years through collections of ticks and blood, interviews, telemetry and camera traps in three areas of Serra do Mar State Park, Brazil. Blood samples were used to investigate infection by Rangelia vitalii by real-time TaqMan PCR and Rickettsia parkeri by IIFA. The collected ticks were submitted to conventional PCR to investigate the presence of R. parkeri . These data were compared with the monitoring results and interviews with the owners. Dogs considered as companion presented a risk of infection by R. parkeri strain Mata Atlantica 5.4 times higher than those not considered as companion (p = 0.009). Dogs that had at least one A. ovale collected during the campaigns had a 10 times higher risk of infection by R. parkeri strain Mata Atlantica than those who did not (p = 0.009). One dog positive for R. vitalii by real-time TaqMan PCR was parasitized by A. ovale frequently during monitoring. Sequenced ompaA - positive DNA samples had 100% identity of R. parkeri strain Mata Atlantica clone As106. From the findings, it is urgent to control domestic dogs around rainforests to reduce zoonoses transmission.

Coexistence of Diversified Dog Socialities and Territorialities in the City of Concepción, Chile

There has been scant research on the presence of stray dogs in cities. Studying their very considerable presence in Concepción (Chile) provided a unique opportunity to learn more about the different patterns of sociality and territoriality exhibited by the dog species. Via a set of case studies, we examined the behavior of urban dogs, adopting an ethnographic methodology. This yielded findings of the dogs' cognitive, social and spatial adjustment abilities, i.e., their territorialities. Our hypothesis was validated: We found numerous types of sociability, we confirmed the presence of two previously established categories: family dogs (pets, guard dogs and beggars' dogs) and stray dogs (dogs almost entirely unused to humans, aggressive dogs at the far end of the campus and feral dogs in the woods). We also identified three new ones: familiar stray dogs in packs (dogs both spatially and socially close to humans), pet-stray dogs (i.e., village dogs interacting closely with people) and free-roaming pet dogs. We conclude that an ongoing two-way bond between humans and animals allowed these dogs to became part of a city's urban identity and explains the stray dogs' plasticity in terms of adapting to the diversified urban habitat. We postulate that it was the human culture and range of urban areas in Concepción that gave rise to this unique diversity of sociospatial positioning and level of adjustment (e.g., dogs crossing crosswalks).

The triad "dogs, conservation and zoonotic diseases" - An old and still neglected problem in Brazil

The presence of domestic/free-ranging dogs in Brazilian protected areas and native vegetation fragments is an important problem, mainly because these animals pose a threat to wild species that live in such areas. In addition, dogs constantly circulate between wildlife environments and urban regions, acting as "bridges" in spillover events. Dogs are traditionally recognized as vectors of zoonoses, which are correct, but their roles as facilitating agents for the "jump" of pathogens from wild animals to humans (and vice versa) are sparsely debated. In this context, this work briefly describes the different roles of dogs in the dynamics and ecology of infectious diseases, using the Brazilian scenario as a study model.

Temporal activity of rural free-ranging dogs: implications for the predator and prey species in the Brazilian Atlantic Forest

Domestic or free-ranging dogs (Canislupusfamiliaris) can have deleterious effects on wildlife, acting as predators or competitors to native species. These impacts can be highly important in fragmented pristine habitats or well-preserved areas located in human dominated landscapes and where biodiversity values are usually high, such as those in southeastern Brazil. Here we explored the level of overlap or mismatch in the distributions of activity patterns of rural free-ranging dogs and potential wild prey (Didelphisaurita, Cuniculuspaca; Sylvilagusbrasiliensis) and a wild predator (Leoparduspardalis) in areas of Atlantic Forest in southeastern Brazil. We further explored the possible influence of the wild predator on the dog presence pattern detected in the territory analyzed. Our camera-trap data (714 camera-trap days) showed that while rural free-ranging dogs display a cathemeral activity pattern, with activity peaks at dusk and dawn, ocelot and prey species are mainly nocturnal. Moreover, we found no evidence of an effect of ocelot presence, the distance to human houses and the presence of native forests on site occupancy by dogs. The ocelot activity patterns in this study were similar to those already reported in previous studies. On the other hand, previous studies have indicated that that free-ranging dogs are often reported to be more diurnal, and it seems that the rural free-ranging dogs in our study area may have adjusted their behaviour to be more active at dawn and dusk periods. This might be to both maintain some overlap with potential prey, e.g. Sylvilagusbrasiliensis, and also to avoid ocelots by being less active in periods when this predator is more active (which also coincides with peaks in activity for potential prey species). We hypothesize that the presence of ocelots might be influencing the temporal niche dimension of rural free-ranging dogs. As a sustainable management strategy, we propose conserving territories to promote the presence of medium to large predators in natural areas, in order to control free-ranging dogs and protect their vertebrate prey species.

Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador

Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km) were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus), puma (Puma concolor), striped hog-nosed skunk (Conepatus semistriatus), and Andean bear (Tremarctos ornatus)]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

Endoparasites in domestic animals surrounding an Atlantic Forest remnant, in São Paulo State, Brazil

Morro do Diabo State Park (MDSP) is a significant remnant of the Atlantic Rain Forest in Brazil and is surrounded by rural properties. In that area, wild and domestic animals and humans are in close contact, which facilitates the two-way flow of infectious diseases among them. We assessed endoparasites in domestic livestock from all rural properties surrounding MDSP. There were sampled 197 cattle, 37 horses, 11 sheep, 25 swine, 21 dogs, one cat and 62 groups of chickens from 10 large private properties and 75 rural settlements. Eimeria spp. was present in almost all hosts, excepted in horses, dogs and cats. Giardia cysts were present only in cattle. Nematodes were found in swine, ruminants and horses in high prevalence. Ancylostoma, Toxocara and Sarcocystis were found in dogs. Chickens were found with coccidia, Ascaridida and Capillaria spp.. These parasites can cause malnutrition and reproductive disorders for their hosts. Strategies to prevent and control the spread of endoparasites can improve wildlife, animal and human health in this area.

LE, Uribe Y. A, Muskus C, Hidalgo. M, Gil. J, Cienfuegos G. AV, Osorio Q. L, Rojas A. C. Eco-epidemiological analysis of rickettsial seropositivity in rural areas of Colombia: A multilevel approach

Rickettsiosis is a re-emergent infectious disease without epidemiological surveillance in Colombia. This disease is generally undiagnosed and several deadly outbreaks have been reported in the country in the last decade. The aim of this study is to analyze the eco-epidemiological aspects of rickettsial seropositivity in rural areas of Colombia where outbreaks of the disease were previously reported. A cross-sectional study, which included 597 people living in 246 households from nine hamlets in two municipalities of Colombia, was conducted from November 2015 to January 2016. The survey was conducted to collect sociodemographic and household characteristics (exposure) data. Blood samples were collected to determine the rickettsial seropositivity in humans, horses and dogs (IFA, cut-off = 1/128). In addition, infections by rickettsiae were detected in ticks from humans and animals by real-time PCR targeting gltA and ompA genes. Data was analyzed by weighted multilevel clog-log regression model using three levels (person, household and hamlets) and rickettsial seropositivity in humans was the main outcome. Overall prevalence of rickettsial seropositivity in humans was 25.62% (95%CI 22.11–29.12). Age in years (PR = 1.01 95%CI 1.01–1.02) and male sex (PR = 1.65 95%CI 1.43–1.90) were risk markers for rickettsial seropositivity. Working outdoors (PR = 1.20 95%CI 1.02–1.41), deforestation and forest fragmentation for agriculture use (PR = 1.75 95%CI 1.51–2.02), opossum in peridomiciliary area (PR = 1.56 95%CI 1.37–1.79) and a high proportion of seropositive domestic animals in the home (PR_20-40% vs _<20% = 2.28 95%CI 1.59–3.23 and PR_>40% vs _<20% = 3.14 95%CI 2.43–4.04) were associated with rickettsial seropositivity in humans. This study showed the presence of Rickettsia antibodies in human populations and domestic animals. In addition, different species of rickettsiae were detected in ticks collected from humans and animals. Our results highlighted the role of domestic animals as sentinels of rickettsial infection to identify areas at risk of transmission, and the importance of preventive measures aimed at curtailing deforestation and the fragmentation of forests as a way of reducing the risk of transmission of emergent and re-emergent pathogens.

Rocky Mountain spotted fever is one of the main diseases transmitted by tick bites in Colombia. Studies examining rickettsial seropositivity in humans, potential vectors and amplifying hosts in regions where previous outbreaks occurred are necessary to highlight this disease in the differential diagnosis of febrile syndromes and to implement epidemiological surveillance programs. This study reveals several factors associated with rickettsial seropositivity, including working outdoors, practices related to deforestation and forest fragmentation, and the potential contact between humans and wild animals, such as opossums, that could be involved in the transmission cycle. In addition, it reveals the importance of domestic animals as sentinels of infection as well as the tick species acting as potential vectors of rickettsiae in human and domestic animals.

Association of the occurrence of Brazilian spotted fever and Atlantic rain forest fragmentation in the São Paulo metropolitan region, Brazil

Brazilian Spotted Fever (BSF) is a zoonotic disease caused by the bacterium Rickettsia rickettsii. In the São Paulo Metropolitan Region (SPMR) it is transmitted by Amblyomma aureolatum ticks. In this region, annual lethality of the disease can reach 80% and spatial occurrence depends on environmental factors and more particularly on the presence and interaction of domestic and wild carnivores as well as the presence and characteristics of the remnant Atlantic Rain Forest patches. This study analyzed the association between forest fragmentation and its influence on the risk of occurrence of the disease in the human population. Domestic dogs tested for R. rickettsii antibodies in nine different areas under the influence of different patterns of Rain Forest fragmented landscapes and human occupancy. Landscape metrics were obtained by analyzing satellite images and high-resolution orthophotos. Principal component analysis (PCA) was used to determine among the different landscape variables the one that could best explain the data variance, and the results were tested against canine seroprevalence in order to address disease occurrence risk levels. From 270 canine samples, the seroprevalence ranged from 0 to 37%. PCA showed an inverse correlation between functionally connected large forest patches and the canine seroprevalence for R. rickettsii (p=0.030; Spearman's R=-0.683), while there was a positive correlation between forest border effect and canine seroprevalence (p=0.037; Spearman's R=- 0.909). The further attributed disease occurrence risk level supported the real spatial prevalence of the disease reported for the last eight years (p=0.023; Spearman's R=0.63). The results suggest an important relation of deforestation and fragmentation with the occurrence of BSF in the SPMR.

Risk factors for gastrointestinal parasite infections of dogs living around protected areas of the Atlantic Forest: implications for human and wildlife health

Despite the ubiquity of domestic dogs, their role as zoonotic reservoirs and the large number of studies concerning parasites in urban dogs, rural areas in Brazil, especially those at the wildlife-domestic animal-human interface, have received little attention from scientists and public health managers. This paper reports a cross-sectional epidemiological survey of gastrointestinal parasites of rural dogs living in farms around Atlantic Forest fragments. Through standard parasitological methods (flotation and sedimentation), 13 parasite taxa (11 helminths and two protozoans) were found in feces samples from dogs. The most prevalent were the nematode Ancylostoma (47%) followed by Toxocara (18%) and Trichuris (8%). Other less prevalent (<2%) parasites found were Capillaria, Ascaridia, Spirocerca, Taeniidae, Acantocephala, Ascaris, Dipylidium caninum, Toxascaris, and the protozoans Cystoisospora and Eimeria. Mixed infections were found in 36% of samples, mostly by Ancylostoma and Toxocara. Previous deworming had no association with infections, meaning that this preventive measure is being incorrectly performed by owners. Regarding risk factors, dogs younger than one year were more likely to be infected with Toxocara, and purebred dogs with Trichuris. The number of cats in the households was positively associated with Trichuris infection, while male dogs and low body scores were associated with mixed infections. The lack of associations with dog free-ranging behavior and access to forest or villages indicates that infections are mostly acquired around the households. The results highlight the risk of zoonotic and wildlife parasite infections from dogs and the need for monitoring and controlling parasites of domestic animals in human-wildlife interface areas.

Population Estimation Methods for Free-Ranging Dogs: A Systematic Review

The understanding of the structure of free-roaming dog populations is of extreme importance for the planning and monitoring of populational control strategies and animal welfare. The methods used to estimate the abundance of this group of dogs are more complex than the ones used with domiciled owned dogs. In this systematic review, we analyze the techniques and the results obtained in studies that seek to estimate the size of free-ranging dog populations. Twenty-six studies were reviewed regarding the quality of execution and their capacity to generate valid estimates. Seven of the eight publications that take a simple count of the animal population did not consider the different probabilities of animal detection; only one study used methods based on distances; twelve relied on capture-recapture models for closed populations without considering heterogeneities in capture probabilities; six studies applied their own methods with different potential and limitations. Potential sources of bias in the studies were related to the inadequate description or implementation of animal capturing or viewing procedures and to inadequacies in the identification and registration of dogs. Thus, there was a predominance of estimates with low validity. Abundance and density estimates carried high variability, and all studies identified a greater number of male dogs. We point to enhancements necessary for the implementation of future studies and to potential updates and revisions to the recommendations of the World Health Organization with respect to the estimation of free-ranging dog populations.

Human-related factors regulate the presence of domestic dogs in protected areas

The presence of domestic species such as dogs Canis familiaris in protected areas can cause problems for native species as a result of competition, predation and disease transmission. To improve our ability to design effective control policies we investigated the factors affecting detection of dog tracks in a Mediterranean national park.

We investigated the presence of dogs across 69 2 × 2 km grid squares in Doñana National Park in south-west Spain and used logistic regression models to analyse the associated environmental and human constraints. We did not detect dogs in areas away from the edges of the national park close to human settlements (track census effort > 470 km) and the detection of dog tracks was correlated with human presence. We conclude that domestic dogs occasionally enter the Park from the surrounding area and are a direct threat to wildlife at the edges of the Park. Management actions to reduce the effects of domestic dogs in protected areas where feral dog populations are not established should focus on the spatial extent of local settlements, regulation and awareness-raising to encourage responsible dog-ownership, and control measures such as removing un-owned dogs from boundaries and areas close to human dwellings, and forbidding unleashed dogs in public facilities.

Comparison of two mammalian surveys made with camera traps in southeastern Brazil, focusing the abundance of wild mammals and domestic dogs

Sampling allows assessing the impact of human activities on mammal communities. It is also possible to assess the accuracy of different sampling methods, especially when the sampling effort is similar. The present study aimed at comparing two mammalian surveys carried out over a three-year interval, in terms of sampling effort, capture success, abundance of domestic dogs, impact of human activities, and relative biomass using camera traps, in the Serra do Japi Biological Reserve and surroundings, located in Jundiaí, state of São Paulo, southeastern Brazil. The total richness recorded was 13 species, one domestic and 12 wild mammals. Sampling effort in both surveys was similar, but capture success and number of captures differed. The abundance of wild mammals and dogs did also differ between surveys. There was a highly significant correlation between abundance of wild mammals and capture effort for the survey performed in 2006/2007, but not for the survey performed in 2009/2010. The difference between samples may be related to human disturbance, since the number of domestic mammals photographed was higher in the second survey, three years after the first survey. Despite being a reserve, the area is still under pressure from urbanization, biological invasion, environmental degradation, and hunting, which may reduce the abundance of wild mammals.

Size and spatial distribution of stray dog population in the University of São Paulo campus, Brazil

A longitudinal study was carried out to describe the size and spatial distribution of the stray dog population in the University of São Paulo campus, Brazil from November 2010 to November 2011. The campus is located within the urban area of São Paulo, the largest city of Brazil, with a population over 11 million. The 4.2 km(2) that comprise the university grounds are walled, with 10 access gates, allowing stray dogs to move in and out freely. Over 100,000 people and 50,000 vehicles circulate in the campus daily. Five observations were made during the study period, using a mark-resight method. The same route was performed in all observations, being traveled twice on each observation day. Observed animals were photographed and the sight coordinates were obtained using a GPS device. The estimated size of the stray dog population varied from 32 (CI 95% 23-56) to 56 (CI 95% 45-77) individuals. Differences between in- and outward dog movements influenced dog population estimates. Overlapping home ranges of docile dogs were observed in areas where most people circulate. An elusive group was observed close to a protected rain forest area and the estimated home range for this group did not overlap with the home ranges for other dogs within the campus. A kernel density map showed that higher densities of stray dog sighting is associated with large organic matter generators, such as university restaurants. We conclude that the preferred source of food of the stray dogs on the University of São Paulo campus was leftover food deliberately offered by restaurant users. The population was stable during the study period and the constant source of food was the main reason to retain this population within the campus.