Capybaras in an anthropogenic habitat in Southeastern Brazil

Gastrointestinal parasite assemblages from the wild rodent capybara (Hydrochoerus hydrochaeris) inhabiting a natural protected area from Argentina

Knowledge about parasitic diseases of wildlife will help us to understand the dynamics of parasites and their effects on host populations. The capybara (Hydrochoerus hydrochaeris) is the largest living rodent in the world, and its distribution is associated with the presence of tropical and subtropical wetlands in South America. The Los Padres Lake Integral Reserve (LPLIR) is an important conservation zone in the pampean region of Argentina. One of the emblematic species found within the reserve is the capybara. The objective of this study was to determine the gastrointestinal parasites present in wild capybaras of the LPLIR and to compare different coprological methodologies. Free-ranging capybara fresh feces from 57 individuals were randomly collected from the area of LPLIR in the summer of 2022. Three different techniques were applied: spontaneous sedimentation technique (SS), INTA modified McMaster technique (MM), and Mini-FLOTAC (MF) technique. Fifty-six samples from all samples analysed (56/57, 98%) were found to be positive for gastrointestinal parasites. Two species of Strongylida, Protozoophaga obesa, Echinocoleus hydrochaeris, one unidentified nematode, one unidentified spirurid, and at least two morphotypes of Eimeria spp. oocysts were recorded. There were found significant differences in the proportion of positive samples and in richness by technique, but no significant differences were found in parasite counting. In conclusion, the choice of methodology depends on the specific objectives of the study. This is the first parasitological study of capybaras from the LPLIR and represents an exploration of parasite communities present in these wild rodents at their southernmost distribution.

Absence of Giardia spp. in fecal samples from capybaras (Hydrochoerus hydrochaeris) inhabiting urban areas in the state of Mato Grosso do Sul, Brazil

Giardiasis is a major cause of diarrhea in humans and animals worldwide. Currently, there are nine species of Giardia, including Giardia duodenalis, which infects most vertebrates. The capybara (Hydrochoerus hydrochaeris) is the largest herbivorous rodent in the world. Although capybaras are hosts of several parasites of public health importance, including helminths and protozoa, there is a paucity of research on their zoonotic potential. We investigated the prevalence of Giardia spp. in populations of capybaras living in urban areas. Fecal samples from 247 capybaras were collected in Lagoa Maior, located in the municipality of Três Lagoas, and in Lago do Amor and Parque das Nações Indígenas, both located in the municipality of Campo Grande, state of Mato Grosso do Sul, Brazil. Fecal samples from capybaras originated from 133 adults (54%), 61 cubs (25%), and 53 juveniles (21%); 183 samples were collected in the rainy season and 64 in the dry season. Giardia spp. DNA was screened by the small-subunit ribosomal RNA (SSU rRNA) targeted PCR. Samples with DNA band sizes suggestive of Giardia spp. amplicons were examined by PCR targeting the glutamate dehydrogenase (GDH) and triosephosphate isomerase (TPI) genes. PCR amplicons were subjected to genetic sequencing. Nested PCR screening of the SSU rRNA gene revealed 16 samples showing faint DNA bands in gel electrophoresis with sizes similar to Giardia spp. amplicons. PCR amplicons of the SSU rRNA gene were analyzed by Sanger sequencing. Most of the sequencing reactions failed, and the chromatogram reads of some samples were ambiguous, suggesting nonspecific amplification. Therefore, all the capybara fecal samples were considered negative for Giardia spp. Two published studies on Giardia spp. in capybaras reported findings similar to ours, i.e., the absence or a low positivity rate for Giardia spp. However, further studies are needed to determine the possible role of capybaras in the epidemiology of giardiasis.

Capybara Ticks and the Urban Context of Spotted Fever in Brazil: An Overview

Spotted fever is caused by Rickettsia rickettsii and is transmitted through tick’s saliva. Humans, ticks, and capybaras (Hydrochoerus hydrochaeris) are often coexisting in environments that favor the spread of Brazilian spotted fever (BSF). Although capybaras do not transmit R. rickettsii, they can amplify these bacteria among tick vector populations, playing a significant role in the one health approach and epidemiology of the disease. Urban populations of capybaras have increased, especially in Southeast Brazil, as well as the number of cases and lethality of BSF have increased in the country since the 1980s. This expansion is mainly determined by the availability of food and the absence of predators. Thus, urban areas, including parks and university campuses, provide an abundance of food and protection against predators, ensuring the multiplication of the species and increasing the risk of transmission to humans due to the proximity of man with animals in the urban environment. Therefore, this chapter aims to address aspects of spotted fever, considering the many dimensions of the species involved, contributing to public strategies and policies.

Morphometric Patterns and Blood Biochemistry of Capybaras (Hydrochoerus hydrochaeris) from Human-Modified Landscapes and Natural Landscapes in Brazil

The capybara, Hydrochoerus hydrochaeris, is the largest extant rodent of the world. To better understand the correlation between size and body mass, and biochemical parameters of capybaras from areas with different degrees of anthropization (i.e., different food supplies), we sampled free-ranging capybaras from areas of natural landscapes (NLs) and human-modified landscapes (HMLs) in Brazil. Analyses of biometrical and biochemical parameters of capybaras showed that animals from HMLs were heavier (higher body mass) than those from NL, a condition possibly related to fat deposit rather than body length, as indicated by Body Condition Index (BCI) analyses. Biochemical parameters indicated higher serum levels of albumin, creatine kinase, cholesterol, fructosamine and total protein among capybaras from HMLs than from NLs; however, when all adult capybaras were analyzed together only cholesterol and triglycerides were positively correlated with body mass. We propose that the biochemical profile differences between HMLs and NLs are related to the obesity condition of capybaras among HMLs. Considering that heavier animals might live longer and reproduce more often, our results could have important implications in the population dynamics of capybaras among HMLs, where this rodent species is frequently represented by overgrowth populations that generate several levels of conflicts with human beings.

Space use and activity of capybaras in an urban area

Due to the rapid growth of urban environments, interactions between animals and humans in cities are increasingly common. Large mammals, such as capybaras (Hydrochoerus hydrochaeris), provide benefits to people and biodiversity of urban areas, but can also result in conflicts, such as animal–vehicle collisions or disease transmission. As a consequence, understanding the space use of urban capybara, and the effect of human activity on capybaras, is conducive to the promotion of coexistence. We studied the home range and the role of human disturbance on activity and habitat selection of urban capybaras in the city of Campo Grande (Brazil). We monitored nine groups of capybaras living at four parks: two parks subjected to high human visitation on workdays and two on weekends. Home range of the urban capybaras in the study is larger than those reported in previous studies of wild capybaras. The capybaras under study presented a bimodal activity pattern, which was delayed on days of high human presence, increasing animals’ nocturnality. In addition, habitat selection was completely altered on days of high human presence, leading animals to increase avoidance of urban areas and reversing the selectivity patterns for forests, grasslands, and water bodies, that capybaras show on days with low human presence. Even when completely surrounded by an anthropic environment, our results indicate that a mosaic of grasslands near a water body and forested areas will allow capybaras to maintain daily activity and large home ranges. However, human presence significantly altered the daily activity patterns and habitat selection of capybara. Urban planners should account for these data to improve the coexistence of capybaras with humans and thereby minimize the potential for conflicts.

Human-modified landscapes alter home range and movement patterns of capybaras

The expansion of human activity forces species to co-exist with people in human-modified landscapes (HMLs). However, living in HMLs demands behavioral adaptations, and the proximity between wildlife and people heightens human–wildlife conflicts. Capybara (Hydrochoerus hydrochaeris) is a thriving rodent species in HMLs in Brazil and as such, is involved in human–wildlife conflicts, such as vehicle collisions and transmission of Brazilian spotted fever (BSF). Despite their public importance, the effects of HMLs on capybara movement behavior have never been investigated. Our study aimed to investigate changes in home range, ranging pattern, and activity, for capybaras in six HMLs and two natural landscapes (NLs) by monitoring capybaras with GPS collars. We found home ranges 2.43 times greater in NLs than in HMLs and differences in ranging pattern in HMLs. Capybaras tended to be more nocturnal and move shorter distances across HMLs than NLs. Our results confirm the impacts of the HMLs altering capybara movement. The aggregation of capybaras in very small home ranges might imply on greater risks of tick infestations. In addition, capybara–vehicle collision may be increased during capybaras’ nocturnal activity. Therefore, we recommend that transportation agencies avoid the construction of transportation infrastructures (roads, railways, airstrips) in capybaras’ home ranges, which should be of restricted access to people in BSF endemic areas.

Multi-elemental exposure assessment through concentrations in hair of free-ranging capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) in the Atlantic Forest remnants, Northeast of Brazil

This study aimed to determine the mineral profile of hair samples of free-ranging capybaras (Hydrochoerus hydrochaeris) in remnants of the Atlantic Forest located in the Northeast of Brazil, and to evaluate the effects of origin, gender and age of the animals on their mineral accumulation in hair. Twenty hair samples from animals of different areas, genders and ages were prepared using microwave-assisted digestion, employing 5 mL of HNO₃ and 2.5 mL of H₂SO₄ for 100 mg of sample. Digestion efficiency was assessed by residual carbon content. The digested samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES). Principal component analysis (PCA) was performed considering the composition data of 11 elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Mo, and Na). The digestion method applied was efficient and the most abundant elements with their respective concentration ranges in mg kg^-1 were Al (396-2746), Ca (36-3420), Fe (476-51180), K (115-4843), and Na (72-473). ANOVA and PCA differentiated among the capybaras regarding age (adults) and origin (A3), both associated with higher concentrations of Al, Cd, Fe, and K. Although a higher metal bioaccumulation was observed in adult animals, it is important to highlight that this result could have been affected by diet and physiological parameters. The results suggest that A3 was the most anthropized remnant area due to agricultural and urban influences. Multi-elemental determination in hair can be used as a non-invasive method to assess heavy metal contamination in capybaras.

An estimate of wild mammal roadkill in São Paulo state, Brazil

Roadkill estimates for different species and species groups are available for many countries and regions. However, there is a lack of information from tropical countries, including from Latin America. In this study, we analyzed medium and large-sized mammal roadkill data from 18 toll road companies (TRC) in São Paulo State (6,580 km of monitored toll roads), Brazil. We extrapolated these roadkill numbers to the entire system of major paved roads in the State (36,503 km). The TRC collected mammal-road- mortality data both before (2-lanes) and after (4-lanes) road reconstruction. We used the "before" data from the TRC to estimate annual mammal-road-mortality along 2-lane roads that remained public roads. Combined with the data for the new 4-lane highways, this allowed us to estimate annual mammal road mortality for all the paved roads in the State. During 10 years of roadkill monitoring along toll roads, a total of 37,744 roadkilled mammals were recorded, representing a total of 32 medium to large-sized mammal species (average number of roadkilled individuals/year = 3,774 ± 1,159; min = 1,932; max = 5,369; 0.6 individuals roadkilled/km/year). Most roadkilled species were common generalists, but there were also relatively high roadkill numbers of threatened and endangered species (4.3% of the data), which is a serious conservation concern. Most of the roadkill was reported occurred during the nocturnal period (66%, n = 14,189) and in the rainy months (October-March) (55%, n = 15,318). Reported mammal roadkill tended to increase between 2009 and 2014 (R2 = 0.614; p = 0.065), with an average increase of 313.5 individuals/year. Extrapolation of the results to the entire São Paulo State, resulted in an average estimate of 39,605 medium and large-sized mammals roadkilled per year. Our estimates of the number of roadkilled individuals can be used as one of the input parameters in population viability analyses to understand the extinction or extirpation risk, especially for threatened and endangered species.

Natural Habitat, Housing, and Restraint of Six Selected Neotropical Animals in Trinidad and Tobago with the Potential for Domestication

This paper highlights the natural habitat, housing, and restraint needs of 6 Neotropical animals that are found in Trinidad and Tobago with the potential for domestication: agouti (Dasyprocta leporina), lappe/paca (Cuniculus paca/Agouti paca), capybara (Hydrochoerus hydrochaeris), manicou/opossum (Didelphis marsupialis insularis), collared peccary (Tayassu tajacu/Pecari tajacu), and red brocket deer (Mazama americana). The year of the earliest reference cited was 1950 and the most recent was 2018, with over 100 references being used. The average density, home range size, social group, and housing requirements were also examined as these factors would play a role in designing enclosures. A number of different physical and chemical restraint techniques were also discussed. Information from other species within the same genus was incorporated as some of the animals did not have sufficient literature.

Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) Infecting Amblyomma sculptum (Acari: Ixodidae) Ticks and Capybaras in a Brazilian Spotted Fever-Endemic Area of Brazil

The bacterium Rickettsia rickettsii is the agent of Brazilian spotted fever (BSF), a highly fatal disease that is transmitted in Brazil mainly by the tick Amblyomma sculptum Berlese, which uses capybaras (Hydrochoerus hydrochaeris Linnaeus) as major hosts. In 2015, we captured nine capybaras in a BSF-endemic area of southeastern Brazil. From each capybara, we collected blood sera that were tested through the immunofluorescence assay using Rickettsia spp. antigens, and A. sculptum ticks, processed for isolation of R. rickettsii through guinea pig inoculation. All capybaras (100%) were seroreactive to Rickettsia spp., with highest titers to R. rickettsii. A total of 166 A. sculptum ticks were macerated and inoculated into nine guinea pigs, from which only one presented high fever and seroconverted to R. rickettsii. Blood from this febrile animal was inoculated into additional guinea pigs (guinea pig passages), which also became febrile and seroconverted, or when euthanized during the fever period, their internal organs (spleen, lung) were shown to contain R. rickettsii DNA. The present rickettsial isolate has been maintained cryopreserved as infected guinea pig organs. There was at least one R. rickettsii-infected tick among the 166 macerated ticks, giving a minimal infection rate of 0.6% (1/166). This infection rate is within the range of previous studies, which reported that only 0.05% to at most 1.28% A. sculptum ticks were infected by R. rickettsii in other BSF-endemic areas. These low infection rates support the low incidence of BSF, despite of A. sculptum being the most frequent human-biting tick in southeastern Brazil.

Brazilian Spotted Fever Prevention through a Nonlethal Capybara Population Control Strategy

INTRODUCTION

Brazilian spotted fever (BSF), a lethal tick-borne Rickettsioses (2000 - 2018 >600 human deaths) involving synanthropic capybara as host.

METHODS

We introduced an alternative to mitigate human-capybara conflicts and epidemiologic concerns of BSF. Complex aspects like transmission dynamics, risk areas, host mobility, and birth rate control, were considered to develop a prevention strategy using an anti-GnRH vaccine.

RESULTS

The propositioned immunocontraceptive potentially remove and prevent the spread of BSF from endemic areas.

CONCLUSIONS

We propose the anti-GnRH vaccine as a BSF prevention strategy based on these favorable results.

Epidemiology of capybara-associated Brazilian spotted fever

Background

Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, has been associated with the transmission by the tick Amblyomma sculptum, and one of its main hosts, the capybara (Hydrochoerus hydrochaeris).

Methods

During 2015–2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome, all with established populations of capybaras.

Results

The BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, when compared to the BSF-nonendemic areas. Only two tick species (A. sculptum and Amblyomma dubitatum) were found in the anthropic areas; however, with a great predominance of A. sculptum (≈90% of all ticks) in the endemic areas, in contrast to a slight predominance of A. dubitatum (≈60%) in the nonendemic areas. Tick species richness was higher in the natural areas, where six species were found, albeit with a predominance of A. sculptum (≈95% of all ticks) and environmental tick burdens much lower than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. In contrast, the BSF-nonendemic areas with landscape similar to the endemic areas differed by having lower tick burdens and a slight predominance of A. dubitatum over A.sculptum, both sustained chiefly by capybaras. While multiple medium- to large-sized mammals have been incriminated as important hosts for A. sculptum in the natural areas, the capybara was the only important host for this tick in the anthropic areas.

Conclusions

The uneven distribution of R. rickettsii infection among A. sculptum populations in highly anthropic areas of São Paulo state could be related to the tick population size and its proportion to sympatric A. dubitatum populations.

Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is the deadliest tick-borne disease of the New World. In southeastern Brazil, where 489 patients succumbed to the disease from 2001 to 2018, R. rickettsii is transmitted to humans mainly by the tick Amblyomma sculptum, which uses the capybara (Hydrochoerus hydrochaeris) as its main host. During 2015–2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome. The BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, with a predominance of Amblyomma sculptum. In the BSF-nonendemic areas, another tick species, Amblyomma dubitatum, outnumbered A. sculptum. In the natural areas, six tick species were found; however, with much lower numbers than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. Results of this study support the idea that any intervention resulting in a drastic reduction of the A. sculptum population shall eliminate the R. rickettsii infection from the tick population, and consequently, prevent new BSF cases.

A morphological, molecular and life cycle study of the capybara parasite Hippocrepis hippocrepis (Trematoda: Notocotylidae)

Hippocrepis hippocrepis is a notocotylid that has been widely reported in capybaras; however, the molluscs that act as intermediate hosts of this parasite remain unknown. Furthermore, there are currently no molecular data available for H. hippocrepis regarding its phylogenetic relationship with other members of the family Notocotylidae. In the present study, we collected monostome cercariae and adult parasites from the planorbid Biomphalaria straminea and in the large intestine of capybaras, respectively, from Belo Horizonte, Minas Gerais, Brazil. We subjected them to morphological and molecular (amplification and sequencing of partial regions of 28S and cox-1 genes) studies. Adult parasites collected from the capybaras were identified as H. hippocrepis and the sequences obtained for both molecular markers showed 100% similarity with monostome cercariae found in B. straminea. The sequences obtained for H. hippocrepis were compared with data available in public databases; analysis revealed this species differs from other notocotylids with available sequences (1.5–3.8% with respect to 28S and 11.4%–13.8% with respect to cox-1). On the phylogenetic analyses, H. hippocrepis appeared to be a distinct lineage in relation to other notocotylids. Some ecological aspects related to the infection of capybaras with H. hippocrepis are briefly discussed.

Single Stranded DNA Viruses Associated with Capybara Faeces Sampled in Brazil

Capybaras (Hydrochoerus hydrochaeris), the world's largest rodents, are distributed throughout South America. These wild herbivores are commonly found near water bodies and are well adapted to rural and urban areas. There is limited information on the viruses circulating through capybaras. This study aimed to expand the knowledge on the viral diversity associated with capybaras by sampling their faeces. Using a viral metagenomics approach, we identified diverse single-stranded DNA viruses in the capybara faeces sampled in the Distrito Federal, Brazil. A total of 148 complete genomes of viruses in the Microviridae family were identified. In addition, 14 genomoviruses (family Genomoviridae), a novel cyclovirus (family Circoviridae), and a smacovirus (family Smacoviridae) were identified. Also, 37 diverse viruses that cannot be assigned to known families and more broadly referred to as unclassified circular replication associated protein encoding single-stranded (CRESS) DNA viruses were identified. This study provides a snapshot of the viral diversity associated with capybaras that may be infectious to these animals or associated with their microbiota or diet.

Hosts mobility and spatial spread of Rickettsia rickettsii

There are a huge number of pathogens with multi-component transmission cycles, involving amplifier hosts, vectors or complex pathogen life cycles. These complex systems present challenges in terms of modeling and policy development. A lethal tick-borne infectious disease, the Brazilian Spotted Fever (BSF), is a relevant example of that. The current increase of human cases of BSF has been associated with the presence and expansion of the capybara Hydrochoerus hydrochaeris, amplifier host for the agent Rickettsia rickettsii and primary host for the tick vector Amblyomma sculptum. We introduce a stochastic dynamical model that captures the spatial distribution of capybaras and ticks to gain a better understanding of the spatial spread of the R. rickettsii and potentially predict future epidemic outcomes. We implemented a reaction-diffusion process in which individuals were divided into classes denoting their state with respect to the disease. The model considered bidirectional movements between base and destination locations limited by the carrying capacity of the environment. We performed systematic stochastic simulations and numerical analysis of the model and investigate the impact of potential interventions to mitigate the spatial spread of the disease. The mobility of capybaras and their attached ticks was significantly influenced by the birth rate of capybaras and therefore, disease propagation velocity was higher in places with higher carrying capacity. Some geographical barriers, generated for example by riparian reforesting, can impede the spatial spread of BSF. The results of this work will allow the formulation of public actions focused on the prevention of BSF human cases.

Complex systems as the Brazilian Spotted Fever (BSF), present challenges in terms of modeling and policy development. BSF human cases have been associated with the presence and expansion of the capybara Hydrochoerus hydrochaeris, amplifier host for the agent Rickettsia rickettsii and primary host for the tick vector Amblyomma sculptum. We developed a reaction-diffusion system for the spread of BSF by considering the spatial structure and migration of amplifier hosts to gain a better understanding of the spatial spread of the R. rickettsii and potentially predict future epidemic outcomes. We performed stochastic simulations and numerical analysis to investigate the impact of potential interventions to mitigate the spatial spread of the disease. Our results indicate that as we vary the amount of capybaras’ food sources, the velocity at which the disease advances is roughly proportional to the carrying capacity, hence proportional to the local risk of zoonotic infection. Some geographical barriers, generated for example by riparian reforesting, can generate positive ecological impacts and can impede the spread of BSF to humans.

Capybara meat: An extraordinary resource for food security in South America

The available information on capybara (Hydrochoerus hydrochaeris) meat, an important resource for the subsistence of many traditional communities in several South American countries, is reviewed. Some features of the species, such as an herbivorous diet, high prolificacy, rapid growth rate, tameness, and social behaviour, which allow its commercial use through harvesting in Venezuela and farming in Brazil, where commercial hunting is not allowed, is discussed. Key characteristics of capybara meat, is low saturated fat and cholesterol content. Discussions about management and handling practices regarding animal welfare and capybara meat quality are also highlighted. After commenting on ethical, political, and economic implications of wildlife use it is concluded that capybara meat has an extraordinary potential to satisfy the growing demand for healthy and high-quality protein of animal origin for the subsistence of many people in the Neotropics.

CAPIVARAS (Hydrochoerus hydrochaeris) E A PRESENÇA DO CARRAPATO (Amblyomma sculptum) NO CAMPUS DA UFSCAR-ARARAS, SÃO PAULO

Resumo Capivaras são territoriais e vivem em grupos sociais, ocorrendo comumente em áreas antropizadas. Em algumas regiões do Brasil, estes animais apresentam infestação por carrapatos do gênero Amblyomma, que por sua vez são considerados como principal vetor biológico e reservatório natural da bactéria Rickettsia rickettsii, agente causador da Febre Maculosa Brasileira. Na UFSCar campus Araras, a interação entre capivaras, carrapatos e comunidade acadêmica é frequente, ocorrendo principalmente durante a estação seca. Este estudo teve como objetivo realizar um censo populacional das capivaras que ocupam o campus, identificando sua área de uso e se estes roedores se encontravam infestados por carrapatos. Realizou-se observação direta das capivaras, captura-marcação e recaptura com uso de um brete, e também coleta dos carrapatos nas capivaras e no ambiente. Registrou-se um total de 56 capivaras, com densidade de 1,50 ind./ha. Foram capturados 24 animais, sendo 25% machos e 75% fêmeas, dos quais 25% eram adultos, 45,8% jovens e 29,2% filhotes. A espécie de carrapato amplamente encontrada infestando tanto os animais como o ambiente foi A. sculptum. Conclui-se que o grupo de capivaras apresentou um número elevado de indivíduos por causa da abundância de recursos e ausência de predadores, e também com grande infestação por carrapatos.

Habitat or matrix: which is more relevant to predict road-kill of vertebrates?

Abstract We believe that in tropics we need a community approach to evaluate road impacts on wildlife, and thus, suggest mitigation measures for groups of species instead a focal-species approach. Understanding which landscape characteristics indicate road-kill events may also provide models that can be applied in other regions. We intend to evaluate if habitat or matrix is more relevant to predict road-kill events for a group of species. Our hypothesis is: more permeable matrix is the most relevant factor to explain road-kill events. To test this hypothesis, we chose vertebrates as the studied assemblage and a highway crossing in an Atlantic Forest region in southeastern Brazil as the study site. Logistic regression models were designed using presence/absence of road-kill events as dependent variables and landscape characteristics as independent variables, which were selected by Akaike’s Information Criterion. We considered a set of candidate models containing four types of simple regression models: Habitat effect model; Matrix types effect models; Highway effect model; and, Reference models (intercept and buffer distance). Almost three hundred road-kills and 70 species were recorded. River proximity and herbaceous vegetation cover, both matrix effect models, were associated to most road-killed vertebrate groups. Matrix was more relevant than habitat to predict road-kill of vertebrates. The association between river proximity and road-kill indicates that rivers may be a preferential route for most species. We discuss multi-species mitigation measures and implications to movement ecology and conservation strategies.

Reproductive ecology of coypu (Myocastor coypus Molina, 1782) in the Middle Delta of the Paraná River, Argentina

The objective of this study was to estimate and compare some important reproductive parameters of Myocastor coypus over time (June 2006-May 2008), in wetlands of the Middle Delta of the Paraná River (MD) Entre Ríos province, R. Argentina. Within the original coypu distribution range, the MD is among the areas of highest habitat suitability for the species. Coypus were captured and the following reproductive parameters were estimated on a monthly, seasonal and annual basis: pregnancy rate (PR), litter size (LS), gross productivity (GP) and annual production (AP). Statistical non-parametric tests were used for comparisons. Additionally, the expected birth date of each embryo and fetus was estimated by assigning it to a developmental stage category and considering the gestation period of the species. All the parameters showed high values and PR and LS differed significantly between the dry (2006) and humid years (2007). Two peaks of birth were detected, one in spring and another one in mid-autumn. The implications of these results for ensuring the sustainable management of this rodent are discussed.

Hydrochoerus hydrochaeris: ECOLOGIA E POTENCIAL DA ESPÉCIE PARA PRODUÇÃO - UMA REVISÃO

A capivara (Hydrochoerus hydrochaeris), maior roedor existente, é considerado um animal silvestre de interesse econômico. Entretanto, no Brasil, restrições legais impedem o desenvolvimento de sistemas de manejo das populações silvestres livres. Fora do Brasil, há o exemplo da Venezuela, onde é praticada a exploração sustentável das populações silvestres de capivaras, por meio da caça controlada, que é uma opção viável para o controle deste roedor e uma nova fonte de renda para a população. Essa revisão foi redigida com o objetivo de discutir sobre a ecologia da espécie, a sua importância para a produção animal, padrões de consumo da carne e mercado consumidor.

Aquatic Ecosystems, Human Health, and Ecohydrology

This chapter treats two main topics: the relationship between human health, aquatic ecosystems, and water use; and the necessity of interdisciplinary approaches for the development of water management policies and disease control.

Main waterborne diseases, mostly affecting developing countries and relevant in terms of water management and changes in land use, such as malaria, schistosomiasis, or cholera, are discussed stressing links to the global water crisis. Also, the role of artificial and natural wetlands in influenza epidemics is treated. The effects of increasing water use and scarcity on human health are discussed considering historical and contemporary incidence of diarrheal diseases in European and South Asian megacities, relationships between dams and on waterborne diseases in Asia and Africa, and intensive agri- and aquaculture resulting in man-made ecotones, fragmented aquatic ecosystems, and pathogen mutations.

It is emphasized that the comprehension of the multiple interactions among changes in environmental settings, land use, and human health requires a new synthesis of ecohydrology, biomedical sciences, and water management for surveillance and control of waterborne diseases in basin-based, transboundary health systems. Surveillance systems should monitor changes in water management, ecotones, and hydrological cycles and shifts in, for example, the outbreak timing of strongly seasonal diseases. These indicators would provide criteria for the development of innovative water management policies, combining methods of vector control and the safe creation of water reservoirs, irrigation systems, and wetland habitats.

Experimental infection of capybaras Hydrochoerus hydrochaeris by Rickettsia rickettsii and evaluation of the transmission of the infection to ticks Amblyomma cajennense

The present study evaluated the infection of capybaras (Hydrochoerus hydrochaeris) by Rickettsia rickettsii and their role as amplifier hosts for horizontal transmission of R. rickettsii to Amblyomma cajennense ticks. Two groups of two capybaras each were evaluated: on day 0, group 1 (G1) was infested by R. rickettsii-infected ticks, and group 2 (G2) was inoculated intraperitoneally with R. rickettsii. Two additional groups were control groups, not exposed to R. rickettsii, being CG1 group the control of G1, and CG2 group the control of G2. Capybara rectal temperature was measured daily. Blood samples were collected every 3 days during 30 days, and used to (i) inoculate guinea pigs intraperitoneally; (ii) DNA extraction followed by real-time PCR targeting the rickettsial gene gltA; (iii) hematology; (iv) detection of R. rickettsii-reactive antibodies by indirect immunofluorescence assay (IFA). Blood was also collected from G1 capybaras every approximately 10-30 days till the 146th day, to be tested by serology. Capybaras were infested by uninfected A. cajennense nymphs from the 3rd to the 18th day. Engorged nymphs were collected, allowed to molt to adults in an incubator. Thereafter, the subsequent flat ticks were tested by PCR. All G1 and G2 capybaras became infected by R. rickettsii, as demonstrated by guinea pig inoculation and seroconversion, but they showed no fever. Rickettsemia was continually detected from the 6th (G2 capybaras) or 9th (G1 capybaras) to the 18th day post inoculation or infestation with R. rickettsii-infected ticks. A total of 20-25% and 30-35% of the flat ticks previously fed on G1 and G2 capybaras, respectively, became infected by R. rickettsii. The study demonstrated that R. rickettsii was capable to infect capybaras without causing clinical illness, inducing rickettsemia capable to cause infection in guinea pigs and ticks. Our results indicate that capybaras act as amplifier host of R. rickettsii for A. cajennense ticks in Brazil.

Natural infection with zoonotic subtype of Cryptosporidium parvum in Capybara (Hydrochoerus hydrochaeris) from Brazil

A total of 145 capybara (Hydrochoerus hydrochaeris) fecal samples from the state of São Paulo, Brazil, were screened for Cryptosporidium spp. oocysts using the malachite green method. Eight samples (5.52%) showed positive results and were further submitted to nested PCR reaction for amplification of fragments of 18S rRNA gene and 60-kDa glycoprotein gene for determination of species, alleles and subtypes of Cryptosporidium. Sequencing of the PCR products of the 18S rRNA gene fragments and 60-kDa glycoprotein gene fragments showed that for both genes all Cryptosporidium isolates from capybara were respectively 100% genetically similar to a bovine isolate of C. parvum and to C. parvum subtype IIaA15G2R1. To the best of our knowledge this is the first report of Cryptosporidium infection in this rodent. The finding of zoonotic C. parvum infection in a semi-aquatic mammal that inhabits anthroponotic habitats raises the concern that human water supplies may be contaminated with zoonotic Cryptosporidium oocysts from wildlife.

Detectability of capybaras in forested habitats

Direct count has been commonly used as an abundance index to estimate wildlife population size. However, systematic errors in sample-based estimators are common in sampling animal populations. At this study we aimed to estimate capybara's observability, through a detectability index in forested habitats. Sampling surveys of capybaras population was obtained by direct count (abundance index) and also by complete count (census). The average detectability index of capybaras in forested habitats was 0.63 ± 0.32 for a single observer. The variability in the detectability index among habitats was due to the presence of more or less dense vegetation. This information might be useful for management purposes of the species in the agroecosystems of southeastern Brazil where species is widespread and overabundant.