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Context: Invasive rodents pose a substantial threat to biodiversity and are a leading cause of species decline and extinction on islands. Population suppression using ground-based methods is common practice, though arboreal behaviour of rodents may render control programs less effective. Aims: We aimed to quantify species-specific invasive rodent activity (Rattus rattus , R. exulans , Mus musculus) across three forest strata to determine the prevalence of arboreal rodent behaviour in a system that has undergone extensive long-term rodent baiting, and therefore assess the suitability of solely ground-based baiting in this system. Methods: We calculated rodent presence at the ground, mid-storey, and canopy using three detection methods (camera traps, chew cards and tracking tunnels) deployed for 30-day periods across three structurally distinct forest types (canopy heights ranged from 3.5 to 16.7 m). We developed continuous rodent activity indices for each method, which we paired with density estimates. Strata-specific species composition was determined using camera trap images. Key results: Rodent presence was recorded equally across all strata, with R. rattus dominating above-ground strata. Rodent densities differed significantly between forest types, which was largely consistent with activity indices. Conclusions: Our findings offer an additional explanation for reduced efficacy of long-term ground-based control programs: arboreal behaviour may exacerbate the reduction in efficacy often associated with long-term control. Implications: Effective management of invasive rodent species on islands is a global conservation challenge. Our findings suggest above-ground control may be required in some long-term suppression programs or eradication campaigns, particularly in the presence of the black rat. Introduced rodents are highly destructive island invaders the world over. Control programs are usually ground-based, however our study found that black rats (Rattus rattus) dominated the forest mid-storey and canopy, casting doubt on the effectiveness of solely ground-based programs. Including above-ground control in the conservationist's rodent control arsenal may improve outcomes for island biodiversity. [ABSTRACT FROM AUTHOR]

Aotearoa—New Zealand has only four rodent species, all introduced. In order of arrival, they are Pacific rat Rattus exulans, brown rat R. norvegicus, house mouse Mus musculus, and black rat R. rattus. Rodent management in New Zealand aims mainly to conserve indigenous biodiversity rather than to protect crops or manage diseases, as is usual elsewhere. We describe four major "regimes" and one major vision for rodent control in New Zealand to meet ecological restoration objectives. Current challenges for island eradications are for large islands that are remote or populated by people. Aerial 1080 is the only large‐scale (tens of thousands of hectares) option for black rat control, but its application requires adjustment to counter subsequent rapid black rat repopulation. Unfenced "ecosanctuaries" (mean 720 ha) use ground‐based traps and poisons to target mainly black rats and face constant reinvasion. Ecosanctuaries with mammal‐resistant fences (up to 3500 ha) limit reinvasion and target more pest species and have enabled the return of previously extirpated taxa to the main islands. Predator Free 2050 aims to eradicate the rat species (but not mice) plus some other introduced mammals from New Zealand by 2050. This vision is not attainable with current tools, but research and experimental management is exploring techniques and technologies. The large scale (to 100 000 ha) at which black rats are now targeted for control to extremely low abundance seems to be unique to New Zealand. [ABSTRACT FROM AUTHOR]

Simple Summary: Invasive species negatively affect native populations through predation, competition, and the potential introduction of health threats, such as parasites. Black rats (Rattus rattus) are among the worst invaders of islands, and a significant source of parasites infecting humans and other animals. This study conducted a screening for zoonotic and veterinary-relevant microparasites in wild rats from small islands in central Italy, including the Pontine Islands and Pianosa, where the primary hosts of the selected parasites were either absent or scarce. The aim was to investigate the potential role of rats as their host. Rats were kill-trapped and molecular analyses were performed on different tissues to identify microparasite presence. Results confirm that invasive species such as rats may contribute to an elevated parasitological threat to local wildlife and human communities in specific ecosystems. Notably, we documented the first record of Babesia divergens, typically associated with cattle and wild ungulates, in wild rats. Additionally, we confirmed the presence of Leishmania infantum on an island without dogs, which have traditionally been considered the primary hosts. Our study helps to document parasite distribution and interactions between parasites and introduced invasive hosts, and represents useful knowledge to inform public health and wildlife management policy. Invasive species have a detrimental impact on native populations, particularly in island ecosystems, and they pose a potential zoonotic and wildlife threat. Black rats (Rattus rattus) are invasive species that disrupt native flora and fauna on islands and serve as potential competent reservoirs for various pathogens and parasites. Microparasites screening was conducted in rat populations from small islands in central Italy (the Pontine Islands and Pianosa) with the aim of assessing the role of rats in maintaining infections, particularly in cases where key reservoir hosts were scarce or absent. We focused on microparasites of zoonotic and veterinary relevance. A total of 53 rats was kill-trapped and target tissues were analysed with molecular techniques. We observed the absence or very low prevalence of Anaplasma spp., while Babesia was found in rats from all locations, marking the first recorded instance of Babesia divergens in wild rats. Data from Pianosa strongly suggest the presence of an autochthonous Leishmania infantum cycle in the Tuscan archipelago islands. Neospora caninum was absent from all islands, even in areas where dogs, the main reservoirs, were present. Toxoplasma gondii was only recorded on the Pontine Islands, where genotyping is needed to shed light on infection dynamics. This study confirms that invasive species, such as rats, may be responsible for maintaining an increased parasitological threat to fauna and human communities in certain ecosystems. [ABSTRACT FROM AUTHOR]

The black rat (Rattus rattus) has become in a commensal relationship with humans and has been responsible for obvious damage to agriculture annually. In this study, clodinafop-propargyl bait (0.98%) was introduced to the adult male rats for seven days under laboratory conditions using a non-choice feeding method. The impact of the compound on the body and some organs' weights and functions was studied. Histopathological changes of the liver, kidney, and testis as well as sperm count, sperm morphology, vitality and motility percent were recorded. The efficiency of clodinafop-propargyl bait (0.98%) was evaluated under field conditions of crop stores. The results demonstrated that the body weight and testis of rats significantly decreased obviously after treatment. As well as, the treatment caused immoderate loss of water through the skin, losing appetite and slow movement of rats. While weights of the liver and kidney of treated rats significantly increased. In addition, the appearance of morphological and histopathological alterations in the liver, kidneys, and testis were observed. Also, significant elevation in serum (ALT and AST) enzymes, urea, creatinine and uric acid levels compared with control after treatment were recorded. Furthermore, sperm count, motility and vitality percentages significantly decreased (p≤0.05) in treated rats compared with controls. There were perspicuous abnormalities in the form of the head, neck, and tail of the spermatozoa in the treated rats. Regarding, sperm motility; non-progressive and immotile grades were significantly increased in treated rats compared with controls. Moreover, clodinafop-propargyl bait (0.98%) proved efficient under crop store conditions as it caused an 86.78 % reduction in the rat population. In conclusion, clodinafop-propargyl bait has a strong toxic impact on the liver, kidneys and reproductive system of male black rats affecting their fertility by destroying testicular integrity and function. Furthermore, the field results proved these impacts and achieved good results. We can conclude that this compound can be used in the control of black rats and can be used in rodent control programs. [ABSTRACT FROM AUTHOR]

Objective. the objective of the present work was the detection of Leishmania sp. in Rattus rattus tail base skin through polymerase chain reaction (PCR) techniques. Material and method. We analyzed 45 Rattus rattus skin samples from the urban area of the city of Corrientes in Argentina. The Leishmania spp detection was performed by nested PCR technique. Results. Leishmania DNA was detected in 22 samples out of 45 processed (49%) in the first round of amplification, and in 14 samples (31%) in the second round (31%). Conclusions. These results contribute to increase the existing information in our region on the possible relationship between Leishmania and Rattus rattus, considering the high prevalence found in skin added to the total absence of lesions. Other aspects should be further studied to establish the role of these animals in the epidemiological chain of the disease in an urban area endemic to leishmaniasis in other animal species. [ABSTRACT FROM AUTHOR]

Rift Valley fever phlebovirus (RVFV) is an arthropod-borne virus that can cause severe disease in ruminants and humans. Epidemics occur mainly after heavy rainfall, which leads to a significant increase in the occurrence of RVFV-transmitting mosquitoes. During inter-epidemic periods, the virus is assumed to be maintained between mosquitoes, susceptible livestock and yet unknown wildlife. The widespread rodent Rattus rattus (black rat) has been suspected to be involved in RVFV maintenance. In order to elucidate its susceptibility and thus its possible role in the transmission cycle of the virus, an experimental infection study was performed. Black rats were subcutaneously infected with highly virulent RVFV strain 35/74 and euthanized on days 3, 14 and 28 post-infection. Additional black rats served as non-infected contact animals. The infected black rats showed high susceptibility to RVFV infection. Generation of RVFV-neutralizing antibodies was found, and the rats developed viraemias lasting up to 17 days. Viral RNA was found in tissues until the last day of the experiment. However, neither a clinical manifestation nor virus-induced histopathological lesions were observed in any rat. These findings indicate the persistence of RVFV in black rats without affecting the animals. In contact animals, no evidence of horizontal RVFV transmission was found, although the co-housed infected rats showed oral, rectal and conjunctival RVFV shedding. Results of this study point to an involvement of black rats in the RVFV transmission cycle, and further studies are needed to investigate their potential role in the maintenance of the virus. [ABSTRACT FROM AUTHOR]

Black rats are considered a carrier of arthropods that are vectors of diseases to animals and humans. No studies have ever been reported on ectoparasites of this rodent in Algeria. Where Rattus rattus was introduced recently in the south-eastern oasis and has taken refuge in palm groves. To identify the ectoparasites, richness, and prevalence of this species, we have collected 6237 arthropods from four species of lice, five mites, one tick, and flea's larvae, were collected from 462 infested rats of 484 (95.5%) total collected rats. The results showed that lice especially Polyplax spinulosa (n = 2888) and P. serrata (n = 1456) were the most trapped ectoparasites followed by Ornithonyssus bacoti (n = 1415). Otherwise, Atricholaelaps sp. (n = 10) was the least population. In addition, adult males of black rat were depicted as the most attacked category compared to females and other classes because of their mobility. Statistics confirm this ascertainment for sex (P = 0.0007) and age groups (P < 0.000). Hence, R. rattus is a favourable host target to parasites when transmission conditions allow it. All inventoried species were significantly greater (P < 0.0000) in summer than winter and decreased rainfall. [ABSTRACT FROM AUTHOR]

Pterodroma leucoptera caledonica is a subspecies of Gould's Petrel endemic to New Caledonia. Its distribution, abundance and breeding biology are poorly known. Extensive surveys of New Caledonia between 1994 and 2014 located only two breeding colonies, and a further likely, but still unconfirmed; the total estimated size of the population could be of the order of 5000–7000 breeding pairs. Nesting burrows were situated either near streams or on slopes near ridges. The breeding phenology of caledonica was similar to that of the Australian leucoptera, but with a breeding calendar that lagged that of leucoptera by 2–4 weeks depending on year and breeding parameter. Breeding success was low, with evidence of a high level of predation of eggs, chicks and adults by rats, pigs and cats. Pigs also destroyed nesting burrows. Permanent bait stations installed to control rats at one colony appeared successful, but the control of pigs and cats is much more problematic. If, as expected, the level of predation observed at one colony extends across all breeding colonies, population decline is inevitable and extinction likely in the long term. With no populations of P. l. caledonica on predator-free offshore islands, translocation to such sites may be evaluated to safeguard this subspecies. In the meantime, we recommend that the global status of Gould's Petrel Pterodroma leucoptera be upgraded from Vulnerable to Endangered. [ABSTRACT FROM AUTHOR]

Gomortega keule is an endangered tree species, the single extant species of a monotypic family. It is safeguarded only in one protected area. Its recruitment and germination are low, possibly in part because rodents prey on the seeds. However, it remains unknown if any rodent preys upon its large fruit and if so, to what extent. In this work we aimed to evaluate the interaction and possible predation of the invasive species Rattus rattus on G. keule. We recorded with camera traps the visits and behaviour of different animal species with the fruit of G. keule. We obtained a total of 90 records. The only animal species that interacted with the fruit during the 14-day observation period was R. rattus, eating and carrying away the fruit. This could constitute an additional threat to G. keule. Despite the evidence of seeds chewed by rodents, it would be useful to document the fates of seeds to confirm our conclusions and understand this interaction. However, in the meantime we recommend increasing propagation and protection of seedlings, and also taking actions against R. rattus in the only protected area where this endangered tree is present. [ABSTRACT FROM AUTHOR]

Brown (Rattus norvegicus) and black (R. rattus sensu lato) rats are among the world's most widespread and important invasive animals; however, there are very few studies of their natural history in natural habitats within their native ranges. Both taxa are native to Japan and still occur in natural habitats there, but have been traditionally treated by zoologists working in the country as invasive pests limited to cities and agricultural lands. We used thermal imaging and snow tracking to conduct the first study of status, distribution and behavioural ecology of remnant human-independent populations of these species in Japan. We found both species still living in natural habitats away from human settlements: brown rat is a rare species in wetlands on the main islands and in upland forests on Hokkaido, while the native taxon of R. rattus species complex, the Asian house rat (R. tanezumi sensu stricto) inhabits remnant deciduous old-growth forests, as well as evergreen subtropical forests, in the south of the country. Such knowledge is critically important for understanding the rats' evolutionary history, invasion biology and behaviour. Future molecular studies should aim to clarify the origin of these populations: possibly they are Pleistocene relicts threatened by hybridisation with rats of related non-native taxa. [ABSTRACT FROM AUTHOR]

The black rat Rattus rattus and the house mouse Mus musculus are two commensal rodent species that harbour and shed zoonotic pathogens, including helminths. The aim of this survey was to study the helminth community and the patterns of infections in R. rattus and M. musculus from two Mayan communities in Mexico. Gastrointestinal helminths were isolated from 322 M. musculus and 124 R. rattus , including Gongylonema neoplasticum , Hassalstrongylus aduncus , Hassalstrongylus musculi , Hydatigera taeniaeformis metacestode, Hymenolepis diminuta , Nippostrongylus brasiliensis , Oligacanthorhynchidae gen. sp., Syphacia muris , Syphacia obvelata , Rodentolepis microstoma and Trichuris muris. The overall richness of helminths was seven in R. rattus and six in M. musculus. The results of generalized linear models showed that juvenile rodents had lower probabilities of being infected with G. neoplasticum , H. taeniaeformis and H. musculi than adult rodents. A positive association between the prevalence of S. muris and rat abundance was found. The intensity of infection with S. muris was higher in the rainy season than in the dry season; the opposite result was found for H. musculi infection. Male R. rattus harboured more S. muris specimens. The intensity of infection with T. muris was inversely associated with mouse abundance. The presence of the zoonotic H. diminuta , as well as H. taeniaeformis and R. microstoma in rodent populations indicates that there is risk of transmission, and that their entire life cycle occurs in the study area. [ABSTRACT FROM AUTHOR]

Rodents have been widely studied as intermediate hosts of Sarcocystis; however, only a few reports on these parasites in the black rat (Rattus rattus) are known. Having examined 13 black rats captured in Latvia, sarcocysts were found in skeletal muscles of two mammals and were described as Sarcocystis ratti n. sp. Under a light microscope, sarcocysts were ribbon-shaped, 0.9–1.3 × 0.09–0.14 mm in size and had a thin (0.8–1.3 μm) and smooth cyst wall. The lancet-shaped bradyzoites were 8.3 × 4.3 (7.5–9.3 × 3.9–4.8) μm. Under a transmission electron microscope, the cyst wall was up to 1.3 μm thick, wavy, the ground substance appeared smooth, type 1a-like. Morphologically, sarcocysts of S. ratti were somewhat similar to those of S. cymruensis, S. rodentifelis, and S. dispersa-like previously identified in the brown rat (Rattus norvegicus). On the basis of 18S rDNA, 28S rDNA, and cox1, significant genetic differences (at least 2.3, 4.5, and 5.8%, respectively) were observed when comparing S. ratti with other Sarcocystis species using rodents as intermediate hosts. While ITS1 sequences of S. ratti were highly distinct from other Sarcocystis species available in GenBank. Phylogenetic and ecological data suggest that predatory mammals living near households are definitive hosts of S. ratti. [ABSTRACT FROM AUTHOR]

The paper summarizes all available information on the black rat (Rattus rattus) occurrence in South Bohemia. Both archaeozoological and zoological data are reviewed. The first record of the black rat in South Bohemia dates back to the late 14th century. Bones of at least six individuals were discovered during archaeological excavation of a non-functional well in the town hall of České Budějovice. The rodent was present there also during the period of mid-15th - early 16th century, as evidenced by finding of the osteological remains of at least two black rats in a waste midden. The other possible medieval locality of the black rat is the Netolice town, where a single bone was collected. The uncertainty of dating is due to the archaeological context, when much younger period is also an option. During the 20th century the black rat mummies were discovered in a house in Český Krumlov town and in a mill nearby České Budějovice. The mummified individuals were dated back to the 18th century and the forties or fifties of the 20th century, respectively. In the 19th century an undated stuffed specimen of the black rat from the Nové Hrady town was stored in the house of Schwarzenberg natural history collections. Whereas voucher specimens for recent occurrences are either lost or dubious, the medieval black rat bones are preserved in the Prachatice Museum and the Museum of South Bohemia in České Budějovice. As there are no records of the black rat in South Bohemia since the 1950s, the species is presumed extinct here. [ABSTRACT FROM AUTHOR]

Rat hepatitis E virus (HEV) is genetically only distantly related to hepeviruses found in other mammalian reservoirs and in humans. It was initially detected in Norway rats ( Rattus norvegicus ) from Germany, and subsequently in rats from Vietnam, the USA, Indonesia, China, Denmark and France. Here, we report on a molecular survey of Norway rats and Black rats ( Rattus rattus ) from 12 European countries for ratHEV and human pathogenic hepeviruses. RatHEV-specific real-time and conventional RT-PCR investigations revealed the presence of ratHEV in 63 of 508 (12.4%) rats at the majority of sites in 11 of 12 countries. In contrast, a real-time RT-PCR specific for human pathogenic HEV genotypes 1–4 and a nested broad-spectrum (NBS) RT-PCR with subsequent sequence determination did not detect any infections with these genotypes. Only in a single Norway rat from Belgium a rabbit HEV-like genotype 3 sequence was detected. Phylogenetic analysis indicated a clustering of all other novel Norway and Black rat-derived sequences with ratHEV sequences from Europe, the USA and a Black rat-derived sequence from Indonesia within the proposed ratHEV genotype 1. No difference in infection status was detected related to age, sex, rat species or density of human settlements and zoological gardens. In conclusion, our investigation shows a broad geographical distribution of ratHEV in Norway and Black rats from Europe and its presence in all settlement types investigated. [ABSTRACT FROM AUTHOR]

field study was conducted to disclose the prevalence of different helminth parasites in the black rat, Rattus rattus, in some regions of Stara Zagora district, Bulgaria. Out of 67 examined rats, 53 (79.1%) were found to be positive. Helminths of three classes were detected such as Cestoda: Hymenolepis diminuta (47.8%), Hymenolepis nana (43.3%), Taenia taeniaeformis larvae (7.5%), Taenia polyacantha larvae (1.5%); Secernentea: Syphacia obvelata (4.5%), Aspiculuris tetraptera (3.0%) and Adenophorea: Capillaria hepatica (9.0%), Trichuris muris (3.0%). Of all the investigated rats, 27 (40.3%) were infected by one helminth species and 26 (38.8%) by more than one. Hymenolepis diminuta was a predominant species in cases of single infections (23.9%). The most frequent co-infections were observed by H. nana and H. diminuta (16.4%). [ABSTRACT FROM AUTHOR]

Trypanosomes and Leishmania are vector-borne parasites associated with high morbidity and mortality. Trypanosoma lewisi, putatively introduced with black rats and fleas, has been implicated in the extinction of two native rodents on Christmas Island (CI) and native trypanosomes are hypothesized to have caused decline in Australian marsupial populations on the mainland. This study investigated the distribution and prevalence of Trypanosoma spp. and Leishmania spp. in two introduced pests (cats and black rats) for three Australian locations. Molecular screening (PCR) on spleen tissue was performed on cats from CI (n = 35), Dirk Hartog Island (DHI; n = 23) and southwest Western Australia (swWA) (n = 58), and black rats from CI only (n = 46). Despite the continued presence of the intermediate and mechanical hosts of T. lewisi, there was no evidence of trypanosome or Leishmania infection in cats or rats from CI. Trypanosomes were not identified in cats from DHI or swWA. These findings suggest T. lewisi is no longer present on CI and endemic Trypanosoma spp. do not infect cats or rats in these locations. [ABSTRACT FROM AUTHOR]

Trypanosomes and Leishmania are vector-borne parasites associated with high morbidity and mortality. Trypanosoma lewisi, putatively introduced with black rats and fleas, has been implicated in the extinction of two native rodents on Christmas Island (CI) and native trypanosomes are hypothesized to have caused decline in Australian marsupial populations on the mainland. This study investigated the distribution and prevalence of Trypanosoma spp. and Leishmania spp. in two introduced pests (cats and black rats) for three Australian locations. Molecular screening (PCR) on spleen tissue was performed on cats from CI (n = 35), Dirk Hartog Island (DHI; n = 23) and southwest Western Australia (swWA) (n = 58), and black rats from CI only (n = 46). Despite the continued presence of the intermediate and mechanical hosts of T. lewisi, there was no evidence of trypanosome or Leishmania infection in cats or rats from CI. Trypanosomes were not identified in cats from DHI or swWA. These findings suggest T. lewisi is no longer present on CI and endemic Trypanosoma spp. do not infect cats or rats in these locations. [ABSTRACT FROM AUTHOR]

Dietary characteristics and environmental variables are important selective factors directing ecological diversification in rodents. On Madagascar, the introductions and spread of the commensal black rat ( Rattus rattus) can be seen as example cases to study dietary niche occupation and dietary adaptation in an insular environment. We investigate how tooth wear as a measure of dietary adaptation of black rats differs between four distinct habitats (village, manioc fields, spiny forest, and rainforest) with different dietary resources. We use the 3D surface texture analysis (3 DST, using 30 parameters according to ISO 25178) as a measure of dietary abrasiveness. 3 DST is applied on the occlusal surface of the upper first molar of 37 black rat specimens. The rainforest sample displays less rough and less voluminous surface textures compared to the village samples as indicated by smaller values for height parameters ( Sa, Sp, Sq), inverse areal material ratio ( Smc), and volume parameters ( Vm, Vmc, Vmp, Vv, and Vvc). We therefore rank sampling areas from highest to lowest abrasiveness (village>manioc fields/spiny forest>rainforest). The rats from villages and rainforest differ to such an extent that one could have interpreted them to belong to different species. This indicates a high degree of variability in terms of ingesta abrasiveness. Furthermore, the pronounced difference between rats from human habitations compared to rats from associated fields or natural vegetation is interpreted to clearly indicate shifts in dietary niche occupation in relation to human impact. [ABSTRACT FROM AUTHOR]

Eradication is often the preferred method of invasive species management on islands; however, its consequences may affect native communities. Feral goats ( Capra hircus), donkeys ( Equus asinus), and pigs ( Sus scrofa) were eradicated from Santiago Island in the Galapagos Archipelago by 2005. Because feral goats were the dominant herbivores on Santiago Island until their eradication, we examined the consequences of goat eradication on the diet of territorial Galapagos Hawks ( Buteo galapagoensis) through a comparative study of observations of prey deliveries to nests before (1999-2000) and after (2010-2011) eradication. We predicted that vegetation recovery after eradication would limit the hawks' hunting success of terrestrial prey and they would therefore switch to predominantly arboreal prey. We did not observe the predicted switch from terrestrial to arboreal prey in the diet; on the contrary, after goat eradication, hawks delivered significantly fewer arboreal prey items. However, introduced black rats ( Rattus rattus) represented a significantly greater proportion of the hawks' diet after eradication, particularly in moderate to dense vegetation (arid and transition habitats), replacing other prey items. Overall, 73% of total prey biomass delivered after eradication consisted of introduced rats, compared to only 20% before eradication. This study documents the complex interaction of predators and introduced prey, even in relatively simple ecosystems. [ABSTRACT FROM AUTHOR]

Background: Rattus norvegicus (brown rat) and Rattus rattus (black rat) are known carriers of bacteria, viruses, and parasites of zoonotic and veterinary importance. Moreover, rats may play a role in the transmission of muscle larvae of the zoonotic nematode Trichinella spiralis to farm animals. We aimed to study the intestinal and intramuscular helminths in wild rats from three different environments to assess the relevance of rats as carrier of zoonotic parasites for public health. Materials and methods: Wild brown rats (117 individuals) and black rats (44 individuals) were captured at farms, in suburban and in rural environments in the Netherlands. Intestinal helminths were isolated and identified morphologically. Artificial digestion was used to isolate muscle larvae. Results and discussion: Morphological analysis of rat intestinal contents yielded six nematode species (Syphacia muris, Heterakis spumosa, Aonchotheca murissylvatici, Trichuris muris, Nippostrongylus brasiliensis, and Strongyloides sp.), three cestode species (Hymenolepis diminuta, H. nana and Hymenolepis (=Rodentolepis) fraterna), and four trematode species (Plagiorchis muris, Plagiorchis proximus, Echinostoma chloropodis, and Notocotylus imbricatus). Black rats at farms displayed the lowest intestinal helminth species variation (six species) and carried overall on average 0.93 species simultaneously. In comparison, brown rats at farms carried seven helminth species and 1.91 species simultaneously. Brown rats from suburban environments displayed the highest species variation (11 species) at 1.82 simultaneous helminth species. Absence of trematodes from rats at farms may suggest limited exchange of rats between farms and surrounding wet rural environments. We report four species of veterinary (Syphacia muris) or zoonotic relevance (Hymenolepis diminuta, Hymenolepis nana and Plagiorchis muris). We did not find Trichinella muscle larvae, consistent with long-term prevalence in Dutch wild rats. [ABSTRACT FROM AUTHOR]

Trypanosomes and Leishmania are vector-borne parasites associated with high morbidity and mortality. Trypanosoma lewisi, putatively introduced with black rats and fleas, has been implicated in the extinction of two native rodents on Christmas Island (CI) and native trypanosomes are hypothesized to have caused decline in Australian marsupial populations on the mainland. This study investigated the distribution and prevalence of Trypanosoma spp. and Leishmania spp. in two introduced pests (cats and black rats) for three Australian locations. Molecular screening (PCR) on spleen tissue was performed on cats from CI (n = 35), Dirk Hartog Island (DHI; n = 23) and southwest Western Australia (swWA) (n = 58), and black rats from CI only (n = 46). Despite the continued presence of the intermediate and mechanical hosts of T. lewisi, there was no evidence of trypanosome or Leishmania infection in cats or rats from CI. Trypanosomes were not identified in cats from DHI or swWA. These findings suggest T. lewisi is no longer present on CI and endemic Trypanosoma spp. do not infect cats or rats in these locations. [ABSTRACT FROM AUTHOR]

The article discusses a study which examines the population recovery of Cassin's auklet after the eradication of Black rats from Anacapa Island, California in November 2002. Findings show the detection of auklet nesting in six shoreline areas on the West and East Anacapa islets in 2012 and the discovery of 42 auklet nests from 2003 to 2012. It concludes the need of further nest monitoring to determine colony growth following the eradication.

Sexual dimorphism is a common trait in many mammal species and sexual-size dimorphism (SSD) represents its commonest form. Rattus rattus and Rattus norvegicus are two cosmopolitan, polygynous species, for which a male-biased SSD has been anecdotally reported, but never quantified. In this work, we assessed the occurrence of SSD in both species and we tested the hypothesis that R. norvegicus has a more evident SSD than R. rattus , in agreement with their body mass-testes size ratio, intra-male aggressive behaviour and mating system. We collected weight data of 40 (20 males and 20 females) adult R. rattus and 27 (13 males and 14 females) adult R. norvegicus from 4 localities in Italy characterized by different habitat typologies. We used a t -test based on Bayesian inference to compare the SSD in both species. The results were in line with our expectation supporting a higher SSD in R. norvegicus than in R. rattus. This study aimed to identify the eco-evolutionary drivers of SSD, and provides further support to well established life history theories on two widely distributed rodent species. [ABSTRACT FROM AUTHOR]

Abstract: Rodents can cause significant damage to grain stores in developing countries, affecting food security and income of small-holder farmers. This study assessed a method to measure the losses caused by rodents to grain stores in rural upland areas of Laos, where black rats, Rattus rattus, are the main rodent pest species. Known amounts of grain were put into metal bowls, placed inside farmer grain stores, and monitored every 2 wk after harvest for a dry and wet season rice crop. There were 2.5–3.0 droppings and 1.4–2.2 hairs per 100-g sample. There was a positive relationship between the number of fecal droppings and hairs from within the bowls and from samples from the grain stores. Weight loss was 10.3% in the dry season and 7.4% in the wet season. There was a weak but positive relationship between fecal droppings and weight loss. It was not possible to ascribe rodent damage to environmental or hygiene conditions. Loss by rodents was calculated at 117 kg, which could feed a Lao household for 1.5 months. Improvements in the methodology are needed to control for interference with the bowls. An experimental approach is suggested to examine potential factors that might influence rodent damage. [Copyright &y& Elsevier]

Wild indigenous small mammals including 83 rodents (bandicoot and black rats, and house mice) and a shrew captured from multiple sites in Vellore, south India, were tested for serological and molecular evidence of hantavirus infection. Indirect immunofluorescence assay (IFA) using Hantaan virus (HTNV) antigen indicated hantavirus-reactive antibodies in 16 (19.3%) of 83 rodents (bandicoot and black rats). Western blot (WB) using Thailand virus (THAIV) antigen confirmed hantavirus-reactive antibodies in nine of the 16 HTNV IFA-positive rodents. Reverse transcription polymerase chain reaction (RT-PCR) of lung and kidney tissue of captured mammals resulted in the detection of partial S segment sequence in a bandicoot rat. This study complements our earlier reports on hantavirus epidemiology in south India and documents first laboratory evidence for rodent-associated hantaviruses in south India. [ABSTRACT FROM AUTHOR]

Control operations for invasive ship rats, Rattus rattus, in New Zealand forests are often followed by increased house mouse, Mus musculus, detections suggesting rats suppress mice. A potential mechanism is intraguild predation, either by interference competition or as simple predatory behaviour. If aggression by rats towards mice is mainly competitive, it should include threat and display features associated with, for example, intraspecific fighting. If predatory, it should lack these features and be associated with feeding. In the first of two captive experiments we observed interactions between paired, live rodents, either side of a wire-mesh screen, and found that most rats were aggressive to mice. This aggression lacked threat and display characteristics typical of encounters with conspecifics and was rarely reciprocated by mice. In a second experiment, euthanized mice were drawn by a line through cages occupied by rats fed either a restricted or unrestricted diet. Rats of both groups attacked and restrained the euthanized mice, and all rats that interacted with the mice ate at least part of them, although food-restricted rats tended to eat more. As the aggressive response of ship rats towards mice lacked threat and display features and was related to feeding, we conclude that it resembles predatory behaviour. Our findings provide a better understanding of the interactions between ship rats and house mice, which hinder their management where they coexist as damaging invaders. However, further research is required to determine whether the results of our captive experiments are consistent with wild rat behaviour. [ABSTRACT FROM AUTHOR]

Abstract: To prioritize conservation actions on Italian islands we used the case study of the eradication of the Black rat Rattus rattus to protect Cory’s shearwater Calonectris diomedea and Yelkouan shearwater Puffinus yelkouan. We evaluated for each island the effectiveness of rat eradication by means of two different indices, both based on the relative importance of the island’s nesting population of the two species at the national and regional scale, but differing in the parameters set at the divisor, i.e., respectively, the number of nesting pairs in rat-free islands and the number of islands occupied by shearwaters. We estimated analytically the monetary costs of rat eradication on each island. Islands at high risk of recolonization were excluded from further analyses, while costs and effectiveness of rat eradication were compared for the remaining islands. Rat eradication was most cost-effectively carried out on the island hosting the largest colony of P. yelkouan. Eradicating rats from all the islands in the ranking provided benefits to 63.9% of the Italian population of P. yelkouan, but only to 7.1% of that of C. diomedea. Comparing costs and effectiveness of all possible island combinations, ranging from a minimum budget of 50,000€ and a maximum of 1600,000€ (i.e. the cost for eradicating rats from all the listed islands), the maximum increase in effectiveness (marginal effectiveness) fell around a relatively small budget (200,000€). For both species, when adopting the cost/effectiveness rankings, the number of pairs protected for 1000€ of investment was significantly higher than adopting rankings of effectiveness alone, demonstrating that conservation priorities are more efficiently identified by including monetary costs in the analysis. [Copyright &y& Elsevier]

Information on the spatial ecology of nonnative roof rats (Rattus rattus) is important for developing management strategies to reduce their impacts on native wildlife in riparian habitats. We determined home-range size and movement patterns of normative roof rats (Rattus rattus) in an old-growth riparian forest in California by radiotracking 12 individuals in August and September 2002. Males had larger home ranges than females. There was considerable overlap of ranges within and between sexes. Rats nested from 2 to 15 m high in trees, and used multiple nests that were sometimes shared simultaneously with other rats. Rats were most active at night, spending most of their time on, or close to the ground, and favoring areas of dense cover of blackberry and grape. [ABSTRACT FROM AUTHOR]

Critically Endangered Puerto Rican parrots Amazona vittata are one of the rarest birds in the world. Several exotic mammal species capable of preying on Puerto Rican parrots cohabit the Caribbean National Forest with the only wild population of these parrots. We used tracking plates, monitoring blocks and trapping to index black rats, small Indian mongooses and feral cats in parrot habitat and in public-use areas in the same habitat type. We had high trap success for black rats at all sites (42% of all sites combined), among the highest reported in the world. Rat response to monitoring (non-toxic bait) blocks was universally high, regardless of ground or tree placement. Mongooses were present at all sites, with a greater proportion of plates tracked within the forest than at public-use sites. Cats were present at all forest sites and one of the public-use sites. Presence of the three species did not appear to be linked to human disturbance. Because only 30-40 Puerto Rican parrots survive in the wild, with as few as three pairs nesting in 2002, we concluded that the abundance and pervasiveness of exotic mammalian predators poses a greater threat to the parrots than has been generally acknowledged. This is evidenced by mammalian predation during recent parrot breeding seasons, including six fledglings taken by mongooses and one nest failure from rats during 2000-2003. [ABSTRACT FROM AUTHOR]

Aim Data on Australian landbridge islands were analysed to seek relationships between the extinction of mammals on islands and a number of variables related to the islands, the native mammal species that occur on them and the presence or absence of exotic mammalian predators. The data base included attributes of the mammals (mean adult body weight, diet and shelter habitat) and of the islands [area, rainfall, presence/absence of significant areas of rockpile habitat, presence/absence of European red fox Vulpes vulpes Linnaeus, 1758, feral cat Felis catus Linnaeus, 1758, and rats Rattus rattus (Linnaeus, 1758) and R. exulans (Peale, 1848)]. Methods Statistical analysis of the 388 cases where a Critical Weight Range (CWR) mammal is extant and the forty-one cases where a CWR mammal is extinct was conducted using logistic regression to model the probability of extinction as a function of the island and mammal variables. Results Foxes and cats are correlated with CWR mammal extinctions, but cats are associated with extinctions particularly on more arid islands. Extinctions are more likely on islands with an absence of significant areas of rockpile habitat and where the native mammal is restricted to the ground's surface, and is relatively large. Conclusions An association between the presence of cats and native mammal extinctions has not previously been demonstrated for Australian islands. The introduction of exotic predators to Australian islands with native mammal species should be avoided and should any of these predators establish all means should be employed to eradicate them. For Australian continental islands the introduction of exotic predators, not habitat clearance, has been the major factor in extinctions. [ABSTRACT FROM AUTHOR]

AbstractThis study investigated the habitats used by an introduced species of rodent, the black rat Rattus rattus (Linnaeus), at North Head in New South Wales, Australia. At a coarse scale, combined live-trapping and radio-tracking indicated that animals used forest proportionately more than open, heath or scrub macrohabitats that were available. To identify the components contributing to this pattern, microhabitat use was assessed by scoring vegetative and structural features around trap stations, and by using spool-and-line tracking. The results indicated that rats preferred microhabitats providing a deep cover of leaf litter and dense understorey with numerous vertical stems. As statistical analysis did not distinguish which of these components was more important in determining habitat use, we designed an experiment to test the importance of a single component: leaf litter. Cover of litter was enhanced experimentally at 75 trap stations and reduced at 75 others, and the response of rats monitored by live-trapping on two occasions. Although no clear response was found in the first run of the experiment, due to low numbers, rats strongly selected trap stations with enhanced leaf litter in the second run. These results indicate that litter cover affects use of habitat by the black rat. Access to food resources and avoidance of predators may contribute to the observed local patterns of abundance. [ABSTRACT FROM AUTHOR]

Abstract: Isolated environments are privileged settings to study transmission of infection. Montecristo is a small island where no wild or domestic carnivores are present. Invasive Black rats Rattus rattus (n =78) were captured and tested by PCR for Leishmania infantum, Toxoplasma gondii and Neospora caninum. We wanted to test, for these parasites, the existence of a sylvatic cycle independent of reservoir or definitive hosts. None of the rats tested positive by PCR for either T. gondii or N. caninum. We recorded a 15.5% prevalence (CI95% 8–26%) of L. infantum in the rats and Phlebotomus mascittii was captured in Montecristo, leading us to identify it as possible vector of the parasite. [Copyright &y& Elsevier]

Investigates the status of the Black rat in Great Britain. Decline of the black rat; Infestations; Coastal distribution of the species; Population.