Commensal Rats Research Articles

Detection of zoonotic pathogens and characterization of novel viruses carried by commensal Rattus norvegicus in New York City.

ABSTRACTNorway rats (Rattus norvegicus) are globally distributed and concentrate in urban environments, where they live and feed in closer proximity to human populations than most other mammals. Despite the potential role of rats as reservoirs of zoonotic diseases, the microbial diversity present in urban rat populations remains unexplored. In this study, we used targeted molecular assays to detect known bacterial, viral, and protozoan human pathogens and unbiased high-throughput sequencing to identify novel viruses related to agents of human disease in commensal Norway rats in New York City. We found that these rats are infected with bacterial pathogens known to cause acute or mild gastroenteritis in people, including atypical enteropathogenic Escherichia coli, Clostridium difficile, and Salmonella enterica, as well as infectious agents that have been associated with undifferentiated febrile illnesses, including Bartonella spp., Streptobacillus moniliformis, Leptospira interrogans, and Seoul hantavirus. We also identified a wide range of known and novel viruses from groups that contain important human pathogens, including sapoviruses, cardioviruses, kobuviruses, parechoviruses, rotaviruses, and hepaciviruses. The two novel hepaciviruses discovered in this study replicate in the liver of Norway rats and may have utility in establishing a small animal model of human hepatitis C virus infection. The results of this study demonstrate the diversity of microbes carried by commensal rodent species and highlight the need for improved pathogen surveillance and disease monitoring in urban environments.

Detection and genetic characterization of Seoul Virus from commensal brown rats in France

BackgroundHantaviruses are single-stranded RNA viruses, which are transmitted to humans primarily via inhalation of aerosolised virus in contaminated rodent urine and faeces. Whilst infected reservoir hosts are asymptomatic, human infections can lead to two clinical manifestations, haemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS), with varying degrees of clinical severity. The incidence of rodent and human cases of Seoul virus (SEOV) in Europe has been considered to be low, and speculated to be driven by the sporadic introduction of infected brown rats (Rattus norvegicus) via ports.MethodsBetween October 2010 and March 2012, 128 brown rats were caught at sites across the Lyon region in France.ResultsSEOV RNA was detected in the lungs of 14% (95% CI 8.01 – 20.11) of brown rats tested using a nested pan-hantavirus RT-PCR (polymerase gene). Phylogenetic analysis supports the inclusion of the Lyon SEOV within Lineage 7 with SEOV strains originating from SE Asia and the previously reported French & Belgian SEOV strains. Sequence data obtained from the recent human SEOV case (Replonges) was most similar to that obtained from one brown rat trapped in a public park in Lyon city centre. We obtained significantly improved recovery of virus genome sequence directly from SEOV infected lung material using a simple viral enrichment approach and NGS technology.ConclusionsThe detection of SEOV in two wild caught brown rats in the UK and the multiple detection of SEOV infected brown rats in the Lyon region of France, suggests that SEOV is circulating in European brown rats. Under-reporting and difficulties in identifying the hantaviruses associated with HFRS may mask the public health impact of SEOV in Europe.

Distinct genetic characteristics of Sri Lankan Rattus and Bandicota (Murinae, Rodentia) inferred from mitochondrial and nuclear markers.

We examined genetic variation in black rats (the Rattus rattus complex) from Kandy District, Sri Lanka using mitochondrial cytochrome b (cytb, 1140 bp) and nuclear melanocortin 1 receptor (Mc1r, 954 bp) gene sequences together with database sequences. We confirmed the existence of two divergent mitochondrial lineages in Sri Lankan black rats, with genetic distance of 2.2% and estimated divergence time of 0.3 million years ago. Because one lineage is unique to the island and the other is closely related to R. rattus populations on the Indian subcontinent, two migration events of R. rattus from the subcontinent are inferred, one ancient and one recent. Mc1r analyses revealed 12 haplotypes among the Sri Lankan black rats. A median-joining network together with other available sequences separated the 12 haplotypes into two groups, one unique to the island and the other related to previously reported R. rattus sequences. Notably, most individuals possessed various combinations of both haplotype groups which had no association with the cytb clades. These results imply that old and new R. rattus lineages are now intermingled as a result of hybridization in Sri Lanka. Specimens of the lesser bandicoot rat (Bandicota bengalensis) collected from Sri Lanka (n = 24) were shown to have no genetic variability in the cytb sequence. Our results indicate that the two most abundant groups of commensal rats in Sri Lanka, black rats and lesser bandicoot rats, are the product of contrasting evolutionary histories on different timescales.

Species or local environment, what determines the infection of rodents by Toxoplasma gondii?

Toxoplasmosis is largely present in rural areas but its spatial distribution in this environment remains poorly known. In particular, it is unclear if areas of high density of cats, the only hosts excreting Toxoplasma gondii, constitute foci of high prevalence. To improve our understanding of the spatial distribution of T. gondii in rural areas, we performed a serological survey in rodents from two villages in France. We trapped 710 rodents including commensal rats and meadow or forest voles and mice. The presence of T. gondii was examined using PCR, mice inoculation and modified agglutination test for antibodies (MAT). We conducted multivariate and discriminant analyses to identify biological, ecological or spatial variables that could explain T. gondii serology in rodents. We then used a logistic regression to assess the relative influence of each explanatory variable. Overall seroprevalence was 4.1%. Commensal-rats were more infected (12.5%) than non-commensal species (3.7%). However, the major determinant of the risk of infection was the distance to the nearest farm (OR = 0.75 for 100 m), which explained the risk in all species or non-commensal species only. We contrast the role of species characteristics and that of the local environment, and discuss the risk of environmental contamination for humans.

Evolutionary history of rat‐borne Bartonella: the importance of commensal rats in the dissemination of bacterial infections globally

Emerging pathogens that originate from invasive species have caused numerous significant epidemics. Some bacteria of genus Bartonella are rodent-borne pathogens that can cause disease in humans and animals alike. We analyzed gltA sequences of 191 strains of rat-associated bartonellae from 29 rodent species from 17 countries to test the hypotheses that this bacterial complex evolved and diversified in Southeast Asia before being disseminated by commensal rats Rattus rattus (black rat) and Rattus norvegicus (Norway rat) to other parts of the globe. The analysis suggests that there have been numerous dispersal events within Asia and introductions from Asia to other regions, with six major clades containing Southeast Asian isolates that appear to have been dispersed globally. Phylogeographic analyses support the hypotheses that these bacteria originated in Southeast Asia and commensal rodents (R. rattus and R. norvegicus) play key roles in the evolution and dissemination of this Bartonella complex throughout the world.

Log-Shape Ratios, Procrustes Superimposition, Elliptic Fourier Analysis: Three Worked Examples in R

This publication uses and presents R routines that perform various morphometric analysis in the context of rodent systematics. The morphological variation of two commensal rat species, Rattus exulans and Rattus tanezumi , is analysed and the potential for discrimination between the two is assessed. Specimens were trapped in three localities of Northern and North-Eastern Thailand. Shape and size variation are analysed in regards to sex, species, and geographical effects with various morphometric methods: log-shape ratios on body measurements, elliptic Fourier analyses on teeth outlines, Procrustes superimposition on skull coordinates. Both species are significantly different; however, the discrimination seems to be better on skull Procrustes coordinates and on teeth size than on other morphometric data set. Where different allometries exist between species and where species differ in size and shape, it is shown that filtering allometry using the approach of Burnaby (1966) can improve the discrimination between species. Sex size and shape dimorphism is reduced by comparison to interindividual variation. Shape variation varies between sampled localities for Rattus exulans , this is not the case for Rattus tanezumi . This pattern is possibly related to the more commensal life of R. exulans . Download the complete Yellow Book on Virtual Morphology and Evolutionary Morphometrics in the new millenium.

The emerging but neglected hepatic capillariasis in China

To the editor, Hepatic capillariasis is a serious parasitic zoonosis caused by the tissue-dwelling nematode Capillaria hepatica (C. hepatica). Humans are an accidental host; human infection is acquired by ingesting food or water contaminated with infective eggs. Hepatic capillariasis may cause clinical signs and symptoms of varying intensity from mild to severe, with a possible fatal outcome. The typical manifestations are persistent fever, hepatomegaly, and eosinophilia[1]. Although human hepatic capillariasis is cosmopolitan, it is frequently scattered in tropical and temperate zones, predominantly in Brazil, America, Mexico, India, Japan, Korea, Germany, Italy, and Czechoslovakia[2]–[4]. Up to 2012, about 40 cases of human infections had been reported in the world. In China, only three human cases were documented, respectively in Guangdong, Fujian and Sichuan provinces of southern China during 1979-2004[5],[6]. However, two cases diagnosed by liver biopsy and two clinical diagnosed cases emerged in Henan province of central China since 2004[7],[8]. In order to assess the risk of human infection with C. hepatica in this province and to strengthen public safety awareness, we conducted an investigation of C. hepatica infection on the rats in seven counties of Henan province during 2008-2011. The results showed C. hepatica eggs were found in 13.62% (157/1153) of the rats. Histologically, lots of eggs in worms were seen in the pressed preparation of liver tissues. The eggs are elliptical in shape, bioperculated, ranging from 51 to 67 mm in length and 30 to 35 mm in width; these eggs have thick shell with striation of the outer layer (Figure 1). But, the prevalence varied from 20.09% (142/707) in house rats to 3.36% (15/446) in field rats (P<0.05). By rat species, C. hepatica were found in 25.83% (109/422) of Rattus norvegicus, significantly (P<0.05) more numerous in this species than in following other species: 12.9% (20/155) in R. flavipectus, 10% (13/130) in Mus musculus, 6.12% (3/49) in R. nivivente, 4.27% (5/117) in Apodemus agrarius, and 2.5% (7/280) in Cricetulus triton. The results show that house rats are the main reservoirs of C. hepatica in Henan province. Figure 1. Morphology of C. hepatica eggs in the liver of the infected rats (unstained). In other areas of China, the prevalence of C. hepatica infection in rat hosts was higher, such as Fujian (11.35%), Zhejiang (18.3%), Yunnan (21.02%), Hubei (19.01%) and Shangdong (27.36%)[9],[10]. C. hepatica infection was also found in other mammals, such as Ochotona curzoniae in Gansu, Tibetan macaques (Macaca thibetana) in Huangshan mountain of Anhui, and the domesticated squirrels in Jingshu province[11],[12]. In addition, the prevalence of C. hepatica infection in commensal rats and shrews caught in traditional wet markets in Taichung city of Taiwan province was 94.1%[13]. However, only a few of cases were reported, it is estimated that many human cases may be neglected, undiagnosed or misdiagnosis, since the patients with fever, hepatomegaly and eosinophilia are not rare. The diagnosis of hepatica capillariasis is quite difficult because the worms and eggs in the hepatic parenchyma can not pass through the digestive tract of the patients. The definite diagnosis is established only by the histological findings in the liver biopsy of C. hepatica eggs. Therefore, the specific serological methods for diagnosis of hepatica capillariasis need to be developed. In addition, because persons in southern China, especially in Guangdong, Hainan and Sichuan, enjoy eating the liver of field rats, 17 cases of human spurious infection with C. hepatica were reported in southern China[14]. Spurious infection occurs when humans ingest the non-embryonated eggs in the liver, these immature eggs do not cause liver disease and merely pass through the digestive tract of hosts with feces. The results of our survey show that 13.62% of the rats infected with C. hepatica in Henan. After the infected rats and other mammals die and the liver decompose, these eggs are disseminated to the soil, where they undergo embryonation, and become the infective mature eggs in 2-6 weeks[15]–[17]. Hence, the ingestion of food or water contaminated with mature eggs poses a high risk for C. hepatica infection. Therefore, public health officials, epidemiologists, parasitologists, veterinarians, and the general public should be aware of such risks and should implement strategies to reduce or eliminate them.

Efficacy of Indoor Residual Spraying Using Lambda-Cyhalothrin for Controlling Nontarget Vector Fleas (Siphonaptera) on Commensal Rats in a Plague Endemic Region of Northwestern Uganda

Over the past two decades, the majority of human plague cases have been reported from areas in Africa, including Uganda. In an effort to develop affordable plague control methods within an integrated vector control framework, we evaluated the efficacy of indoor residual spraying (IRS) techniques commonly used for mosquito control for controlling fleas on hut-dwelling commensal rodents in a plague-endemic region of Uganda. We evaluated both the standard IRS spraying (walls and ceiling) and a modified IRS technique that included insecticide application on not only on walls and ceiling but also a portion of the floor of each treated hut. Our study demonstrated that both the standard and modified IRS applications were effective at significantly reducing the flea burden and flea infestation of commensal rodents for up to 100 d after application, suggesting that IRS could potentially provide simultaneous control of mosquito and fleaborne diseases.

Of Mice and Rats: The Place of Murids in Nage Animal Classification and Symbolism

Abstract The folk zoological taxonomy of the Nage people of central Flores (Indonesia) classifies wild mammals into thirteen named folk generic taxa (sensu Berlin). Of these, nearly half denote murids (rats and mice). In addition, Nage employ dheke, a name that can specifically refer to large commensal rats, to further designate a folk intermediate taxon that subsumes other murid folk generics, thus resulting in a notably more elaborate classification of mice and rats than of other mammals. Murids also receive comparably distinctive treatment in other, special purpose forms of animal classification, and they occupy an especially prominent place in Nage symbolism. The paper considers how these several conceptual orders may be connected, including whether the ethnotaxonomic elaboration of murids may either reflect or be reflected in their symbolic value.

Evaluation of the role of rats as reservoir hosts for fishborne zoonotic trematodes in two endemic northern Vietnam fish farms

Fishborne zoonotic trematodes (FZTs) pose a food safety risk for the aquaculture industry in Vietnam. The risk of being infected from eating raw fish applies not only to humans but also to domestic animals which can serve as reservoir hosts in fish farms. The role of rodents, commonly found in fish farms, as reservoir hosts has not been adequately evaluated. To study this question, commensal and rice field rats were collected from fish farms in Nghia Lac and Nghia Phu communes, Nam Dinh province, Vietnam and examined for FZT infection. A total of 250 rats (Rattus norvegicus, Rattus argentiventer, and Bandicota indica) were collected and examined; the rats were trapped in the farm households (commensal) and in rice fields adjoining the fish ponds (field). The total prevalence of all parasites was 52.8 %: nematodes, 42.4 %; trematodes 18.0 %; and cestodes, (3.6 %), including two zoonotic cestode species, Raillietina celebenisis and Hymenolepis diminuta. Although overall prevalence and intensity of parasite infection did not differ significantly among rat species or between the two communes, the intensity of nematode infection was significantly higher in commensal rats (p < 0.05). The only FZTs recovered were the intestinal flukes Echinostoma cinetorchis and Centrocestus formosanus, both at low prevalence. Because the most common FZTs found in fish from these communes are Haplorchis pumilio and Haplorchis taichui, neither of which were found in the rats, we conclude that rats are not significant reservoir hosts for FZT in these Vietnamese fish farms.

Study of the endoparasitic fauna of commensal rats and shrews caught in traditional wet markets in Taichung City, Taiwan

Rats live in close proximity to human populations. Feral rodents are known to transmit diseases and act as reservoir hosts to many zoonotic parasites that pose health risks to humans. The aim of this study is to investigate endoparasitic infections in commensal rats and shrews caught in traditional wet markets in Taichung City, Taiwan. A total of 51 commensal wild rodents and shrews were caught in traditional wet markets in Taichung City, including 32 Rattus norvegicus, 11 R. rattus, and eight Suncus murinus. All tissues, organs, and intestinal contents were carefully examined after euthanasia for the detection of parasites. The overall prevalence of infection was 94.1%, and the infection rates in R. norvegicus, R. rattus, and S. murinus were 93.8%, 90.9%, and 100.0%, respectively. Four cestodes (Taenia taeniaeformis, Hymenolepis diminuta, H. nana, and Raillietina celebensis), seven nematodes (Angiostrongylus cantonensis, Capillaria hepatica, Heterakis spumosa, Nippostrongylus brasiliensis, Strongyloides ratti, Syphacia muris, and Trichosomoides crassicauda), and one protozoan (Sarcocystis spp.) were detected. Our findings indicate that commensal rodents and shrews found in the traditional wet markets of Taichung City are hosts to various zoonotic parasites and, therefore, pose a serious health risk to humans and domestic animals in Taiwan.

A Study on Rodent Ectoparasites in the North district of Tehran, Iran

Rodent ectoparasites seems have a main role in transmission of some zoonotic pathogens from commensal rats to human and pets such as leishmaniasis, plague, CCHF, etc. So rodents as the main reservoirs, are potential health dangers in human communities. The aim of this study was to determine the prevalence and frequency of identified ectoparasites in north of Tehran . Rodents were captured with live traps during 2007-2009. After transferring to the laboratory and identifying, their ectoparasites were collected and mounted for species identification by using valid keys. Sixty four rodents included two species: Rattus norvegicus ( 82.8%) and Mus musculus (17.2%) were captured. 1755 ectoparasites collected from 43 infested R.norvegicus were related to 5 genera and 6 species: Ornithonyssus bacoti ( 71.7%), Hoplopleura spp ( 17%), Hoplopleura oenomydis ( 11.3%), Polyplax spinulosa ( 3.8%), Nosopsyllus fasciatus (3.8%), and Ixodes ricinus (1.9%). 11 Mus musculus were free of ectoparasites. Among all arthropods, mites and ticks had the most (97.4%) and the least (0.1%) frequency in R.norvegicus , respectively. Also, Ornithonyssus bacoti was a prevalent species (71.7%) with mean abundant 32.2. I.ricinus with 1.9% prevalence was the least prevalent ectoparasites. 11 M.musculus were free of ectoparasites.

Correlation between Protection against Sepsis by Probiotic Therapy and Stimulation of a Novel Bacterial Phylotype

Prophylactic probiotic therapy has shown beneficial effects in an experimental rat model for acute pancreatitis on the health status of the animals. Mechanisms by which probiotic therapy interferes with severity of acute pancreatitis and associated sepsis, however, are poorly understood. The aims of this study were to identify the probiotic-induced changes in the gut microbiota and to correlate these changes to disease outcome. Duodenum and ileum samples were obtained from healthy and diseased rats subjected to pancreatitis for 7 days and prophylactically treated with either a multispecies probiotic mixture or a placebo. Intestinal microbiota was characterized by terminal-restriction fragment length polymorphism (T-RFLP) analyses of PCR-amplified 16S rRNA gene fragments. These analyses showed that during acute pancreatitis the host-specific ileal microbiota was replaced by an "acute pancreatitis-associated microbiota." This replacement was not reversed by administration of the probiotic mixture. An increase, however, was observed in the relative abundance of a novel bacterial phylotype most closely related to Clostridium lituseburense and referred to as commensal rat ileum bacterium (CRIB). Specific primers targeting the CRIB 16S rRNA gene sequence were developed to detect this phylotype by quantitative PCR. An ileal abundance of CRIB 16S rRNA genes of more than 7.5% of the total bacterial 16S rRNA gene pool was correlated with reduced duodenal bacterial overgrowth, reduced bacterial translocation to remote organs, improved pancreas pathology, and reduced proinflammatory cytokine levels in plasma. Our current findings and future studies involving this uncharacterized bacterial phylotype will contribute to unraveling one of the potential mechanisms of probiotic therapy.

Characterization of Rat Odorant Binding Protein Variants and its Post-Translational Modifications (PTMs): LC-MS/MS analyses of Protein Eluted from 2D-Polyacrylamide Gel Electrophoresis

Identification of odorant-binding protein (OBP) variants in mammalian system is of great importance to an understanding of their role in the binding of pheromones and other volatiles during chemical communication. Our previous proteomics studies have revealed the presence of OBP as well as confirming that, in the preputial gland of Indian commensal rat, the bound form of the protein associates with various farnesols. In addition to this, a recent mass spectrometry based proteomics analysis has shown that rat recombinant OBP undergoes post-translational modification (PTM) and there are a number of different variants in terms of phosphorylation. This suggests that the phosphorylation of OBP may affect its binding properties and the binding properties may change in the presence of phosphorylation. Thus, in the present investigation we have investigated these OBP variants. The variants were separated by 2DE-PAGE and protein identification was done using mass spectrometry. The results indicated that OBP has ten variants. Further, we employed anti serine phosphorylation immunoblotting in association with 2DE- PAGE to confirm that three spots were phosphorylation at a serine. In addition to immunoblotting, we also employed structural analysis, by multiple sequence alignment, secondary structural analysis, and a three dimensional analysis of the OBP’s using known lipocalin members. To the best of our knowledge, this is the first report demonstrating PTM variants of an OBP from the preputial gland of the Indian commensal rat.

New Rural Focus of Plague, Algeria

New Rural Focus of Plague, Algeria

Primary Structural Documentation of the Major Urinary Protein of the Indian Commensal Rat (Rattus rattus) Using a Proteomics Platform

A number of proteome studies have been performed recently to identify pheromone-related protein expression and their molecular function using genetically modified rodents' urine. However, no such studies have used Indian commensal rodents; interestingly, in a previous investigation, we confirmed the presence of volatile molecules in commensal rodents urine and these molecules seem to be actively involved in pheromonal communication. Therefore, the present study aims to identify the major urinary protein [MUP] present in commensal rat urine, which will help us to understand the protein's expression pattern and intrinsic properties among the rodents globally. Initially, the total urinary proteins were separated by 1-D and 2-D electrophoresis and then subsequently analyzed by Matrix Assisted Laser Desorption Ionization-Time of Flight and Mass Spectrometer (MALDI-TOF/MS). Furthermore, they were then fragmented with the aid of a Tandem Mass Spectrometer (TOF/TOF) and the identified sequences aligned and confirmed using similarity with the deduced primary structures of members of the lipocalin superfamily. The SDS-PAGE protein profiles showed distinct proteins with molecular masses of 15, 22.4, 25, 28, 42, 50, 55, 68, and 91 kDa. Of these proteins, the 22.4 kDa protein was considered to be target candidate. When 2D elctrophoresis was carried out, about approximately 50 spots were detected with different masses and various pI ranges. The 22.4 kDa protein was found to have a pI of about 4.9.This 22.4 kDa protein spot was digested and subjected to mass spectrometry; it was identified as rat MUP. The fragmented peptides from the rat MUP at 935, 1026, 1192, and 1303 m/z were further fragmented with the aid of MS/MS and generated de novo sequence and this confirmed this protein to be the MUP present in the urine of commensal rats. The present investigation confirms the presence of MUP with a molecular mass of 22.4 kDa in the urine of commensal rats. This protein may be involved in the binding of volatile molecules and opens up a discussion about how volatile and non-volatile molecules in the commensal rats' urine may contribute chemo-communication.

Detection ofα2u-globulin and its bound putative pheromones in the preputial gland of the Indian commensal rat (Rattus rattus) using mass spectrometry

The role of pheromones and pheromone-binding proteins in the laboratory rat has been extensively investigated. However, we have previously reported that the preputial gland of the Indian commensal rat produces a variety of pheromonal molecules and preputial glands would seem to be the predominant source for pheromonal communication. The presence of pheromone-binding proteins has not yet been identified in the preputial gland of the Indian commensal rat; therefore, the experiments were designed to unravel the alpha(2u)-globulin (alpha2u) and its bound volatiles in the commensal rat. Total preputial glandular proteins were first fractionated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) and subsequently analyzed by mass spectrometry. Further, we purified alpha2u and screened for the presence of bound pheromonal molecules with the aid of gas chromatography/mass spectrometry (GC/MS). A novel alpha2u was identified with a high score and this protein has not been previously described as present in the preputial gland of Indian commensal rats. This novel alpha2u was then characterized by tandem mass spectrometry (MS/MS). Peptides with m/z values of 969, 1192, 1303 and 1876 were further fragmented with the aid of MS/MS and generated de novo sequences which provided additional evidence for the presence of alpha2u in the preputial gland. Finally, we identified the presence of farnesol 1 and 2 bound to alpha2u. The present investigation confirms the presence of alpha2u (18.54 kDa) in the preputial gland of the Indian commensal rat and identifies farnesol 1 and 2 as probably involved in chemo-communication by the Indian commensal rat.

Isolation and Genetic Characterization of a Bartonella Strain Closely Related to Bartonella tribocorum and Bartonella elizabethae in Israeli Commensal Rats

Ten Bartonella isolates were cultured from blood drawn from black rats (Rattus rattus) captured in the Tel Aviv area. Genetic characterization included amplification and sequencing of five gene fragments including the ribC, rpoB, 16S, groEL, and gltA and the 16S-23S intergenic spacer region. Sequence comparisons showed that all 10 isolates were identical in all genes studied comprising a total of 3,873 bp analyzed. The sequences of each of the partial genes analyzed indicated a high sequence similarity (97-99.8%) to B. tribocorum or B. elizabethae. The gltA sequence was 100% homologous to a genotype identified in R. rattus in Dhaka, Bangladesh, suggesting the existence of a widespread Asian Bartonella strain infecting the black rats (R. rattus). The detection of a Bartonella genotype closely related to B. elizabethae in the biggest metropolitan center in Israel warrants further study of its zoonotic potential and pathogenic characteristics.

Detecting the initial impact of humans and introduced species on island environments in Remote Oceania using palaeoecology

The isolated archipelagos of Remote Oceania provide useful microcosms for understanding the impacts of initial human colonization. Palaeoecological data from most islands reveal catastrophic transformations, with losses of many species through over-hunting, deforestation and the introduction of novel mammalian predators, the most ubiquitous and devastating being commensal rats. Two case studies from the Austral Islands and New Zealand demonstrate the potential of direct human proxies from palaeoecological archives to detect initial human impacts on islands. We show how pollen from introduced crop plants, and buried seeds with gnaw marks from the introduced Pacific rat (Rattus exulans) provide a reliable means of detecting initial human colonization and highlight the downstream ecological consequences of agriculture and rat introduction on previously uninhabited pristine island ecosystems. Previous studies have relied on indirect signals of human arrival based on charcoal and associated vegetation changes, the causes of which are often more difficult to interpret with certainty.

Eradications as reverse invasions: lessons from Pacific rat (Rattus exulans) removals on New Zealand islands

Eradications of kiore or Pacific rats (Rattus exulans) from islands around New Zealand have been followed by responses from resident species of coastal plants, invertebrates, reptiles and seabirds. These responses are compared with an invasion by ship rats (Rattus rattus), which devastated populations of invertebrates, birds and bats. Post-eradication responses only approximate the effects of invasions because recovery is limited to the residual pool of native species. Greater effects of kiore are indicated by adding incompatible species confined to rat-free locations. The extended list includes at least 15 species of invertebrates, two species of frogs, tuatara (Sphenodon punctatus), 11 species of lizards and 9 species of seabirds. The analyses indicate direct and indirect effects of kiore similar to those reported after ship rat invasions. This is despite indications from the literature that kiore are the least damaging of the three commensal rat species.