Rabbit Research Articles

An Outbreak of Rabbit Hemorrhagic Disease in British Columbia, Canada.

From 2018 to 2019, an outbreak of rabbit hemorrhagic disease virus 2 occurred in British Columbia, Canada, in feral and domestic European rabbits (Oryctolagus cuniculus). Anthropogenic translocation of infected animals is suspected to have played a role in the introduction and spread of the virus.

Hunting dogs bark differently when they encounter different animal species

Previous studies have shown that vocalizations of dogs can provide information to human companions. While acoustic signals of dogs have been intensively studied during the last decade, barking during hunting activities remains unstudied. The experiences of hunters indicate that owners can recognize what animal species has been found based on the bark of their dog. Such a phenomenon has never been tested before. We tested such an ability by comparing barks that were produced when dogs encountered four different animal species: wild boar, red fox, rabbit and fowl. Classification results of a discrimination analysis showed, that based on barks of dachshunds and terriers, it is possible to categorize towards which animal species barks were produced. The most distinctive barks were produced during encounters with the most dangerous of these animals, the wild boar. On the contrary, barks evoked by red fox encounters were classified similarly as those towards other smaller and non-dangerous animals like rabbits and fowl. Although the red fox represents a potentially dangerous species, the barking provoked was not classified with a much higher result than barking at animals that pose no threat. This might indicate that the key parameter could be the body size of the animal the dog meets. We further tested whether the degree of threat from the species of animal the dog encounters is reflected in the structure of the acoustic parameters based on the valence-arousal model. We found that barks produced in contact with a wild boar showed significantly lower frequency parameters and longest duration compared to other barks. According to these results, it seems that the variability of barking depending on the species of animal a dog encounters is an expression of the dogʼs inner state rather than functionally reference information.

Feral animals as a tourism attraction: characterizing tourists’ experiences with rabbits on ōkunoshima Island in hiroshima, Japan

ABSTRACT This study’s aim is to elucidate what tourists’ encounter with feral animals entail—an infrequently studied concept in the literature—by building on the discussion of authenticity in wildlife tourism experiences using the case of feral rabbits. Netnography was used to examine tourists’ comments and photos in 386 TripAdvisor reviews written in Japanese and English about Ōkunoshima Island in Hiroshima, Japan. The findings indicate that the space where tourist and feral rabbit interactions occur can be compared to a ‘natural petting zoo’ and a theme park, where tourists’ seek entertainment rather than authentic experiences. Even uncontrolled, chaotic wildness—the characteristic of feral animals—was consumed by tourists who found it entertaining. Unmediated interactions allowed tourists to be fully in charge of interactions with the rabbits especially through feeding. Their encounters with the rabbits especially left tourists in Japanese reviews with feeling of healing. Widely adopted conservation-based wildlife tourism frameworks are inadequate for managing tourist–feral rabbit encounters because if they were adapted, the rabbits would be eradicated. Therefore, a policy for Ōkunoshima Island that balances the needs of tourists, rabbits, and the surrounding environment is needed.

Monitoring of free-range rabbits using aerial thermal imaging

Unmanned Aerial Vehicles (UAV) imagery is a mature technology, which has found use in a number of applications in agriculture and environmental sciences. However, its application for monitoring and classification of livestock and wild animals has not yet been developed. This study presents a robust methodology to count wild and free-range rabbits and monitor their population. The aims of this study were to 1) test the capacity of the methodology in counting small nocturnal animals such as rabbits in the field, 2) assess the rabbit's density at different sites and different periods of the year and 3) record the temporal pattern of rabbits’ activity during the night hours, with the overall aim to provide a reliable and accurate tool in management studies. For this purpose, a UAV equipped with a thermal camera was used to perform night flights on the island of Lemnos, scanning selected sites and collecting aerial nadir thermal imagery data of the ground. The derived thermal images were analysed using deep learning techniques towards counting the individual animals in each image and the results were compared with manual counting conducted by a researcher. The results revealed that the deep learning approach for automated counting and rabbit recognition overall achieved comparable results to physical counting, with the final model yielding an F1-score of 0.87. However, there were differences between seasons in the methods’ accuracy. This method could be a helpful tool in assessing populations of small nocturnal animals and other free-range livestock animals.

What Are the Keys to the Adaptive Success of European Wild Rabbit (Oryctolagus cuniculus) in the Iberian Peninsula?

Simple SummaryWhy might a species both be seriously threatened and pose an overpopulation problem in introduced locations? The aim of this review was to understand the keys to the adaptive success of the wild rabbit (Oryctolagus cuniculus) in order to establish its strengths and weaknesses for the management of this keystone species in Mediterranean ecosystems. This work highlights the need to create specific conservation programs for this species.The European wild rabbit (Oryctolagus cuniculus) plays an important ecological role in the ecosystems of the Iberian Peninsula. Recently, rabbit populations have drastically reduced, so the species is now considered endangered. However, in some places, this animal is considered a pest. This is the conservation paradox of the 21st century: the wild rabbit is both an invasive alien and an endangered native species. The authors of this review aimed to understand the keys to the adaptive success of European rabbits, addressing all aspects of their biology in order to provide the keys to the ecological management of this species. Aspects including nutrition, genetics, immunity interactions with the environment, behaviour, and conflict with human activities were reviewed. Ultimately, rabbits are resilient and adaptable. The main adaptations that explain the rabbit’s adaptive success are its nutrition (wide adaptation to food and good nutritional use of caecotrophy), immune system (powerful and developed), and other aspects related to genetics and behaviour. Rabbits’ relationship with humans has led them to colonise other places where they have become pests. Despite these adaptations, populations in native places have been drastically reduced in recent years. Since it serves as a bastion of the Mediterranean ecosystem, a specific conservation program for this species must be carried out. Therefore, a study of the rabbit’s response to diseases and nutrition (especially protein), as well as the interaction between them, is of special interest.

A Simplified Population-Level Landscape Model Identifying Ecological Risk Drivers of Pesticide Applications, Part One: Case Study for Large Herbivorous Mammals.

Environmental risk assessment is a key process for the authorization of pesticides, and is subjected to continuous challenges and updates. Current approaches are based on standard scenarios and independent substance-crop assessments. This arrangement does not address the complexity of agricultural ecosystems with mammals feeding on different crops. This work presents a simplified model for regulatory use addressing landscape variability, co-exposure to several pesticides, and predicting the effect on population abundance. The focus is on terrestrial vertebrates and the aim is the identification of the key risk drivers impacting on mid-term population dynamics. The model is parameterized for EU assessments according to the European Food Safety Authority (EFSA) Guidance Document, but can be adapted to other regulatory schemes. The conceptual approach includes two modules: (a) the species population dynamics, and (b) the population impact of pesticide exposure. Population dynamics is modelled through daily survival and seasonal reproductions rates; which are modified in case of pesticide exposure. All variables, parameters, and functions can be modified. The model has been calibrated with ecological data for wild rabbits and brown hares and tested for two herbicides, glyphosate and bromoxynil, using validated toxicity data extracted from EFSA assessments. Results demonstrate that the information available for a regulatory assessment, according to current EU information requirements, is sufficient for predicting the impact and possible consequences at population dynamic levels. The model confirms that agroecological parameters play a key role when assessing the effect of pesticide exposure on population abundance. The integration of laboratory toxicity studies with this simplified landscape model allows for the identification of conditions leading to population vulnerability or resilience. An Annex includes a detailed assessment of the model characteristics according to the EFSA scheme on Good Modelling Practice.

Tularemia Outbreaks in Spain from 2007 to 2020 in Humans and Domestic and Wild Animals.

In this study, tularemia outbreaks associated with humans and several domestic and wild animals (Iberian hares, wild rabbits, voles, mice, grey shrews, sheep, dogs, foxes, wolves, ticks, and river crayfish) are reported in Spain from 2007 to 2020. Special attention was paid to the outbreaks in humans in 2007–2009 and 2014–2015, when the most important waves occurred. Moreover, positive rates of tularemia in lagomorphs were detected in 2007–2010, followed by negative results in 2011–2013, before again returning to positive rates in 2014 and in 2017 and in 2019–2020. Lagomorphs role in spreading Francisella tularensis in the epidemiological chain could not be discarded. F. tularensis is described for the first time infecting the shrew Crocidura russula worldwide, and it is also reported for the first time infecting wild rabbits (Oryctolagus cuniculus) in Spain. Serological positives higher than 0.4% were seen for sheep only from 2007–2009 and again in 2019, while serological rates greater than 1% were revealed in dogs in 2007–2008 and in wild canids in 2016. F. tularensis were detected in ticks in 2009, 2014–2015, 2017, and 2019. Lastly, negative results were achieved for river crayfish and also in environmental water samples from 2007 to 2020.

Role of wild rabbits as reservoirs of leishmaniasis in a non-epidemic Mediterranean hot spot in Spain

There is limited information regarding the role of wild mammals in the transmission dynamics of Leishmania infantum. A potential human leishmaniasis hot spot was detected in southern Spain that could not be explained solely by canine leishmaniasis prevalence. The aim of this work was to analyse the involvement of wild rabbits as the main factor affecting this Mediterranean hot spot. A survey of wild rabbits, dogs and sand flies was conducted in the human cases environment. A nearby region without clinical leishmaniasis cases was used as reference control. 51 wild rabbits shot by hunters were analysed by molecular techniques. 1100 sand flies were captured and morphologically identified. Blood collected from patients’ relatives/ neighbours (n = 9) and dogs (n = 66) was used for molecular analysis and serology. In Mediterranean leishmaniasis hot spots such as Montefrío municipality (average incidence of 16.8 human cases per 100,000 inhabitants/year), wild rabbits (n = 40) support high L. infantum infection rates (100%) and heavy parasite burdens (average value: 503 parasites/mg) in apparently normal ear skin directly accessible to sand flies, enabling the existence of heavily parasitized Phlebotomus perniciosus females (12.5% prevalence). The prevalence of infection and median parasite load were very low among rabbits captured in Huéscar (n = 11), a human clinical leishmaniasis-free area for the last 18 years. P. perniciosus was the most abundant Phlebotomus species in all the domestic/peridomestic microhabitats sampled, both indoors and outdoors. Accordingly, leishmaniasis is clustering in space and time at this local scale represented by Montefrío due to the proximity of two competent host reservoirs (dogs and heavily parasitized wild rabbits) associated with overlapping sylvatic and domestic transmission cycles through the main vector, P. perniciosus. We highlight the usefulness of determining the prevalence of infection and parasite burden in wild rabbits as a control leishmaniasis measure with the advantage that the use of the ear offers.

Pathological and sub-pathological changes in European rabbit bones: Two reference cases to be applied to the analysis of archaeological assemblages

ObjectiveTo provide prevalence data for future comparative analysis of the health status of rabbits (Oryctolagus cuniculus) accumulated in the archaeological record. MaterialsTwo contrasting assemblages were analysed for pathological and sub-pathological changes: 1) an assemblage of domestic modern rabbit bones; and 2) a non-anthropogenic accumulation of archaeological rabbit remains. MethodsThe lesions observed macroscopically, under magnification, and radiographically in both assemblages are quantified and described. ResultsIn the first assemblage, pathological and sub-pathological changes mostly affected the lower limb bones and primarily took two forms: diaphyseal periosteal proliferation and hypervascularised distal physes. Differential diagnosis of the periosteal proliferation suggests that pododermatitis is the most probable cause. In the second assemblage fractures were the most common lesions, but isolated examples of hypervascularised physes, periosteal proliferation, and musculo-skeletal stress markers were also identified. The pathological changes recorded is typical of a naturally-accumulated population of wild rabbits. ConclusionsThe prevalence of pathological and sub-pathological skeletal changes in the rabbits, and thus their health status, are closely related to living conditions. This study demonstrates the value of systematically recording pathologies in rabbit bones. SignificanceWe contribute new data to help understand rabbit interactions with humans in the past and also the environment they inhabited. LimitationsWorking with modern samples frequently means only incomplete skeletons are available for study. In these cases lesion prevalence always needs to be interpreted with caution. Suggestions for further researchPaleopathological studies of rabbit remains are remarkable for their absence. Further exhaustive research in this area is advised.

Age and Infectious Dose Significantly Affect Disease Progression after RHDV2 Infection in Naïve Domestic Rabbits.

Rabbit haemorrhagic disease virus 2 (RHDV2 or GI.2, referring to any virus with lagovirus GI.2 structural genes) is a recently emerged calicivirus that causes generalised hepatic necrosis and disseminated intravascular coagulation leading to death in susceptible lagomorphs (rabbits and hares). Previous studies investigating the virulence of RHDV2 have reported conflicting results, with case fatality rates ranging from 0% to 100% even within a single study. Lagoviruses are of particular importance in Australia and New Zealand where they are used as biocontrol agents to manage wild rabbit populations, which threaten over 300 native species and result in economic impacts in excess of $200 million AUD annually to Australian agricultural industries. It is critically important that any pest control method is both highly effective (i.e., virulent, in the context of viral biocontrols) and has minimal animal welfare impacts. To determine whether RHDV2 might be a suitable candidate biocontrol agent, we investigated the virulence and disease progression of a naturally occurring Australian recombinant RHDV2 in both 5-week-old and 11-week-old New Zealand White laboratory rabbits after either high or low dose oral infection. Objective measures of disease progression were recorded through continuous body temperature monitoring collars, continuous activity monitors, and twice daily observations. We observed a 100% case fatality rate in both infected kittens and adult rabbits after either high dose or low dose infection. Clinical signs of disease, such as pyrexia, weight loss, and reduced activity, were evident in the late stages of infection. Clinical disease, i.e., welfare impacts, were limited to the period after the onset of pyrexia, lasting on average 12 h and increasing in severity as disease progressed. These findings confirm the high virulence of this RHDV2 variant in naïve rabbits. While age and infectious dose significantly affected disease progression, the case fatality rate was consistently 100% under all conditions tested.

Penicillin Treatment Failure in Rabbit Syphilis Due to the Persistence of Treponemes (Treponema paraluisleporidarum Ecovar Cuniculus) in the Focus of Infection.

Rabbit venereal spirochetosis, a disease caused by Treponema paraluisleporidarum ecovar Cuniculus (TPeC), affects both wild and pet rabbits, and is transmitted sexually and via direct contact among animals. Treatment of syphilis in pet rabbits requires administration of antibiotics, including penicillin G, chloramphenicol, or fluoroquinolones. The aim of this work was to elucidate the cause of penicillin treatment failure in rabbit syphilis in a pet rabbit treated in Brno, Czech Republic, and to assess the phylogenetic relatedness of the agent to previously characterized pathogenic treponemes. Following amputation of the infected digits, the second round of penicillin treatment using the same dosage and application route resulted in the disappearance of clinical symptoms within a period of two weeks. The bacterium was successfully isolated from the claws, propagated in three experimental rabbits, and the resulting TPeC strain was designated as Cz-2020. Analysis of four genetic loci revealed that the Cz-2020 strain was similar but also clearly distinct from the only TPeC strain, which had been characterized in detail to date, i.e., the Cuniculi A strain, which was isolated in North America. The strain Cz-2020 represents the first available viable TPeC strain of European origin. DNA sequences encoding five penicillin-binding proteins of the strain Cz-2020 were compared to those of Cuniculi A, which is known to be sensitive to penicillin. The sequences differed in six nucleotides resulting in single amino acid changes in Penicillin-binding protein 1, 2, and 3. Since the second round of treatment was successful, we conclude that the penicillin treatment failure in the first round resulted from the presence of infection foci in claws where treponemes persisted.

Bartonella alsatica in Wild and Domestic Rabbits (Oryctolagus cuniculus) in The Netherlands

Members of the genus Bartonella are Gram-negative facultative intracellular bacteria that are transmitted by arthropod vectors. Bartonella alsatica was detected in the spleens and livers of 7 out of 56 wild rabbits (Oryctolagus cuniculus) and in the liver of 1 out of 87 domestic rabbits in the Netherlands. The molecular evidence of B. alsatica infection in wild as well as domestic rabbits indicates the possibility of exposure to humans when these come in close contact with rabbits and possibly their fleas with subsequent risk of Bartonella infection and disease.

Clinical and pathologic findings in an outbreak in rabbits of natural infection by rabbit hemorrhagic disease virus 2 in the northwestern United States.

Rabbit hemorrhagic disease virus 2 (RHDV2) causes an often-fatal disease of rabbits that has resulted in outbreaks in rabbitries in Europe, Africa, Australia, and Asia. RHD has historically been characterized as a foreign animal disease in the United States. In July 2019, RHDV2 was detected in rabbits on Orcas Island along the northwestern coast of Washington (WA) State following reports of deaths in multiple feral and domestic rabbits. We document and highlight here the unique clinical presentation and gross and histologic lesions observed in this recent WA outbreak. Affected rabbits died without premonitory signs or displayed hyporexia and/or lethargy for ≤1 d prior to death. The most consistent pathologic finding was random, multifocal hepatocellular necrosis, often with concurrent multifocal-to-diffuse splenic necrosis. The lack of significant clinical signs in conjunction with the random distribution of hepatic necrosis in the WA outbreak contrasts with previous reports of RHDV2 disease progression.

Feral rabbit populations in a peri-urban area: insights about invasion dynamics and potential management strategies

Where introduced, the European rabbit Oryctolagus cuniculus is considered among the most destructive and invasive species. To date, research focused mostly on populations of wild rabbit, whereas little is known on feral domestic rabbit populations. In this work, we reported the establishment of two self-sustaining populations of feral rabbits in Italy. Direct observations were conducted to assess rabbit range expansion and population increase over time. We also evaluated prey-predator interactions between rabbits and native red foxes Vulpes vulpes, by means of camera trapping and the analysis of fox scats. Moreover, we also assessed the social perception towards feral rabbits and the acceptability of various management options through the administration of a structured questionnaire to park visitors. Rabbit populations increased between 2018 and 2019, as well as the size of the invaded range. Rabbits are predated by foxes, but they seem to have adapted their activity rhythms to minimize the risk of predation, becoming diurnal. Park visitors loved rabbits and deemed them to be a positive presence in the park, which deserve to live there. Surgical sterilization of rabbits was the only management option which was partially supported. Feral domestic rabbits, albeit a neglected species in invasion biology, can become extremely successful invaders of urban green areas: in < 5 years, rabbits were able to colonize our study area and become a food resource for native predators and also an iconic species. These three points raise concerns about the potential impacts of invasive feral rabbits in European urban green areas and call for further research in this direction.

Incursions of rabbit haemorrhagic disease virus 2 in Canada—Clinical, molecular and epidemiological investigation

Rabbit haemorrhagic disease virus 2 (RHDV2) is a newly emerging Lagovirus belonging to the family Caliciviridae. After its first discovery in 2010 in France, this highly pathogenic virus rapidly spread to neighbouring countries and has become the dominant strain, replacing the classical RHDV strains. RHDV2 was first reported in North America in 2016 in Mont-Joli, Quebec, Canada, and it was reported again in 2018 and 2019 on Vancouver Island and the southwest mainland of British Columbia (BC). The whole genome sequence of the RHDV2 Quebec isolate resembled the 2011 RHDV2-N11 isolate from Navarra, Spain with 97% identity at the nucleotide level. The epidemiological investigation related to this outbreak involved three hobby farms and one personal residence in Quebec. In February 2018, high mortality was reported in a large colony of feral rabbits on the Vancouver Island University Campus, Nanaimo, BC. The virus identified showed only 93% identity to the Quebec RHDV2 isolate at the nucleotide level. Additional cases of RHDV2 on Vancouver Island and on the BC mainland affecting feral and captive domestic, and commercial rabbits were reported subsequently. Vaccination was recommended to control the outbreak and an inactivated bivalent vaccine was made available to the private veterinary practices. In June 2019, an isolated RHDV2 outbreak was reported in pet rabbits in an apartment building in Vancouver, BC. This virus showed only 97% identity to the RHDV2 isolates responsible for the BC outbreak in 2018 at the nucleotide level, suggesting that it was an independent incursion. The outbreak in BC killed a large number of feral European rabbits; however, there were no confirmed cases of RHD in native rabbit species in BC.

Persistence of wild rabbit (Oryctolagus cuniculus) latrines and its implication for monitoring programs

Counting latrines is a standard method to estimate European wild rabbits (Oryctolagus cuniculus) abundance. This method plays an important role in endangered predators’ conservation programs in the Iberian Peninsula, especially in potential reintroduction areas for the Iberian lynx (Lynx pardinus). However, since the last half-century, rabbit populations have declined dramatically within their native range, mainly due to the effect of two viral diseases, which have caused even local extinctions of natural populations. Hence, we raise the question regarding how reliable the method of counting latrines may be in ensuring the abundance of rabbit populations after an event of sudden decline or even local extinction. To answer this question, we carry out a simple experiment where we set ten lines with rabbit latrines with two different sizes each (small and large) and simulated low- and high-abundant rabbit population scenarios on five latrine lines each, respectively. Then, we calculated the pellets decay rate and latrines persistence rate through monthly surveys. Our results showed that the daily persistence rate varied little among the different scenarios. However, generally, latrines do not persist long (78 days on average) regardless of the size of the latrines or rabbit population abundance. The longest time to extinction for pellets (c. 469 days, 97.5 quantile) was longer than the time until no more latrines were identified (c. 191 days, 97.5 quantile). We conclude that, although we did not consider other factors that could affect pellets decay, counting latrines seems to be sensible to a hypothetical dramatic decline event of a wild rabbit population. Therefore, if there is evidence of an epidemiological outbreak event, we suggest managers carry out latrines census at least between 140–220 days after an outbreak detection to reduce bias on the determination of rabbit abundance.

The influence of sharp force trauma on fire’s alteration of bone

The aim of this study was to understand the relationship between sharp force trauma (SFT) and fire. Wild rabbit cadavers were inflicted with varying levels of SFT and their skeletal remains examined after incineration for one hour. The extent and location of the typical patterns of thermal damage on bone were recorded, including weight loss, colour change and fracturing.The results indicate that multiple cases of SFT on a body allow fire greater access to the skeletal remains, resulting in their increased thermal damage. However, the thermal damage of a body that has suffered only a single wound may actually be reduced, particularly where the SFT was in an area of high soft tissue content, such as the torso. It is speculated that the high water content of the soft tissue provided an insulating effect. .SFT following incineration is far easier to detect in areas of low soft tissue, such as defensive wounds to the extremities and the head, and less apparent in areas of high soft tissue, such as the thorax and abdomen.

Keeping an eye on the use of eye-lens weight as a universal indicator of age for European wild rabbits

Accurate methods for age determination are critical to the knowledge of wildlife populations' age structure and, therefore, to their successful management. The reliability of age estimation may have profound economic and ecological consequences on the management of the European wild rabbits, Oryctolagus cuniculus, in its native and introduced range, where it is a keystone species and a major pest, respectively. As in other mammal species, European rabbits' age is often estimated using the Gompertz relationship between age and lens' weight. The growth rate formula has been developed based on data collected from European rabbits introduced in Australia, where a single subspecies (O. cuniculus cuniculus, Occ) is present. However, this curve has never been validated in the species native range, the Iberian Peninsula, where two subspecies (Occ, and O. c. algirus, Oca) coexist naturally. In this study, we tested the relationship between age and lens' weight using 173 Occ and 112 Oca wild rabbits that were surveyed in two experimental facilities in Spain. Our findings show that, in the native range, the published growth curve formula fits well Occ but not Oca data. Therefore, we recommend using the formula reported in this study to estimate the age of Oca (Lens dry weight = 240 × 10(−64.9/(Age+32))). This study supports Oca rabbits' distinctiveness revealed by previous studies, which suggests that management interventions should be applied to protect this subspecies whose distribution range is very narrow and whose populations seem to be declining. More broadly, our findings point to the importance of testing the suitability of growth curves defined for other species with different genetic forms as occurs in the European wild rabbit case.

Molecular epidemiology of Leptospira spp. among wild mammals and a dog in Amami Oshima Island, Japan.

Leptospirosis is a worldwide zoonosis caused by the pathogenic Leptospira spp. Canine and human leptospirosis sometimes occur on Amami Oshima Island, located in the Nansei Archipelago, southwestern Japan; however, information on the causative Leptospira spp. on this island is quite limited. This study aimed to investigate the molecular and serological characteristics of Leptospira spp. isolated from wild animals and a dog in Amami Oshima Island. We obtained seven Leptospira strains by culturing kidney tissues of wild animals, such as black rats (2), wild boars (3), and rabbit (1) as well as blood from a symptomatic dog. Using flaB sequencing and microscopic agglutination test with antisera for 18 serovars, the isolates were identified as Leptospira borgpetersenii serogroups Javanica (black rat), L. interrogans serogroup Australis (black rat and dog), and L. interrogans serogroup Hebdomadis (wild boar and rabbit). The sequence type (ST) of L. borgpetersenii serogroup Javanica was determined to be ST143 via multilocus sequence typing (MLST) using seven housekeeping genes. For L. interrogans, MLST and multiple-locus variable-tandem repeat analysis (MLVA) revealed identical ST and MLVA types in rat and canine isolates, whereas two STs and MLVA types were identified in wild boar isolates. The STs and MLVA types of rabbit and one of the wild boars were identical. Bacterial culture and flaB-nested polymerase chain reaction demonstrated a high rate of Leptospira infection in wild boars (58.3%, 7/12), whereas Leptospira spp. were detected in 4.8% of black rats (2/42). This study revealed diverse Leptospira genotype and serotype maintenance in wild mammals on Amami Oshima Island. MLST and MLVA indicated that black rats were a source of canine infection. Wild boars carry L. interrogans and are considered an important maintenance host because antibodies against serogroup Hebdomadis were detected in human and canine leptospirosis patients on this island.

Low microplastic abundance in Siganus spp. from the Tañon Strait, Central Philippines

Microplastic (MP) occurrence is a major global issue, though data on MP occurrence in the Philippines is limited and the potential effects of MPs on biota are still poorly studied. MP occurrence in fishes remains a concern, especially in economically and ecologically important species such as Siganus spp. This study determined MP occurrence in the gastrointestinal tract of wild rabbit fishes from Tañon Strait, the largest marine protected area in the Philippines. Siganus canaliculatus (n = 65), S. spinus (n = 17), S. guttatus (n = 5), S. virgatus (n = 8) and S. punctatus (n = 1) were sampled from the north and south of the strait. All MPs isolated from the gut of the rabbit fishes except for fibers were chemically analyzed by ATR-FTIR spectroscopy; an established library was used to determine the polymeric identities. Five particles were confirmed as polyester, polyamide, polyethylene or phenoxy resin MPs. The average MP abundance was 0.05 items/individual (S. virgatus > S. guttatus > S. canaliculatus > S. spinus = S. punctatus), which is comparable to studies conducted in other locations using similar methods. Fibers were counted (1556 in total), but not chemically analyzed. The low MP abundance in the samples may be attributed to the capability of rabbit fishes to discriminate food preferences. However, the risks associated with MPs should not be underestimated, especially as all parts of the fishes—including the gut—are utilized as human foods in the Philippines and many other Asian countries.