Rodent Sera Research Articles

Detection of Rickettsia felis in Wild Mammals from Three Municipalities in Yucatan, Mexico.

The aim of this study was to provide information of the occurrence of Rickettsia felis in wild mammals from three municipalities in Yucatan, Mexico. The reactivity of rodent serum to Rickettsia antigens was detected in 80.9% (17 of 21) samples using immunofluorescence assay. Polymerase chain reaction identified rickettsial DNA in spleens of 43.5% (10 of 23) rodents and 57.1% (4 of 7) opossums. The identification of the rickettsial DNA was confirmed as R. felis by restriction fragment length polymorphism and DNA sequencing. This study comprises the first report of R. felis detection in wild mammals in Yucatan.

Novel Small-Molecule Inhibitors Targeting Complement Factor D for Therapy of Paroxysmal Nocturnal Hemoglobinuria

INTRODUCTIONThe complement system is a pivotal player in multiple hematological conditions that include paroxysmal nocturnal hemoglobinuria (PNH). The current standard of care for PNH is intravenous infusion of eculizumab, a humanized monoclonal antibody that targets the terminal complement protein C5 and thereby efficiently impairs intravascular hemolysis. However, a significant fraction of PNH patients in clinical practice respond incompletely to eculizumab due to extravascular hemolysis by immune cells as eculizumab does not prevent erythrocyte opsonization. Additionally, a non-responsive sub-population has been identified with a rare genetic polymorphism in C5 that renders the variant incapable of binding eculizumab. Therefore, an unmet medical need remains for regimens that improve efficacy and that can be administered orally. To achieve this goal, we initiated a discovery program for small molecule inhibitors of complement factor D, a serine protease that is the rate limiting enzyme of the alternative complement pathway. We have obtained high resolution (1.5 Å) crystal structure of inhibitor-bound factor D. Through structure-guided optimization, we have discovered novel inhibitors of factor D that possess high potency and specificity as well as pharmacokinetic properties suitable for oral administration. Herein, we present a biochemical characterization of lead compounds and studies of their activities in various complement-mediated processes. METHODSThe binding affinity to factor D was determined by surface plasmon resonance (Biacore) analysis. The inhibitory effect on factor D protease was evaluated biochemically using both a nonspecific synthetic substrate and a natural substrate consisting of C3b and the complement factor B. The alternative pathway (AP) hemolytic assay was conducted with unsensitized rabbit erythrocytes, 8% human or non-human primate serum, and 10 mM MgEGTA. The classical pathway (CP) hemolytic assay was conducted with antibody-sensitized sheep erythrocytes and 0.5% human serum. To assess inhibition of CP activation through the AP-dependent amplification loop, inhibition of terminal complement complex (TCC) formation by 50% human serum was quantitated following activation by the CP-specific activator HAIGG. Inhibition of complement opsonization and lysis of PNH-like erythrocytes exposed to acidified serum (Ham test) was assessed ex vivo. Finally, selected lead compounds were administered to non-human primates to evaluate the efficacy of factor D inhibitors for blockade of alternative pathway-mediated events. RESULTSLead compounds obtained through optimization bound to factor D with Kd values below 1 nM. Tight binding to factor D of the compounds resulted in potent inhibition of factor D proteolytic activity assessed using a synthetic nonspecific substrate as well as a natural substrate. When evaluated in an AP hemolytic assay with human serum, the most potent compounds inhibited cell lysis with EC50 values below 10 nM. Similar inhibitory activity was observed when compounds were assessed in AP hemolytic assays with non-human primate serum, but not with rodent serum. The compounds showed no activity in a CP hemolytic assay using highly diluted human serum and antibody-coated erythrocytes, indicating specificity for factor D. When evaluated in the presence of 50% human serum and with TCC formation as an endpoint, however, the compounds blocked approximately 75% of TCC formation upon CP activation, a consequence of blockage of the AP-dependent amplification loop. Furthermore, the compounds prevented both opsonisation and lysis of PNH-like cells in the Ham test. Finally, when selected compounds were administered to non-human primates, potent inhibition of TCC formation following ex vivo AP activation was observed with EC50 values below 50 nM. CONCLUSIONSHighly potent and specific factor D inhibitors that block both the terminal pathway and opsonization were discovered using structure-guided design. These orally deliverable inhibitors hold promise as a novel therapeutic approach for treatment of complement-mediated hematological conditions including PNH. DisclosuresMorgan:Swedish Orphan Biovitrum: Consultancy, Research Funding; Glaxo Smith Kline: Consultancy; Achillion Pharmaceuticals: Consultancy, Research Funding. Thanassi:Achillion Pharmaceuticals: Employment. Podos:Achillion Pharmaceuticals : Employment. Phadke:Achillion Pharmaceuticals: Employment. Gadhachanda:Achillion Pharmaceuticals: Employment. Pais:Achillion Pharmaceuticals: Employment. Hashimoto:Achillion Pharmaceuticals: Employment. Wang:Achillion Pharmaceuticals: Employment. Chen:Achillion Pharmaceuticals: Employment. Wang:Achillion Pharmaceuticals: Employment. Agarwal:Achillion Pharmaceuticals: Employment. Deshpande:Achillion Pharmaceuticals: Employment. Huang:Achillion Pharmaceuticals: Employment. Wiles:Achillion Pharmaceuticals: Employment. Huang:Achillion Pharmaceuticals: Employment.

In vitro and in vivo interactions of selected nanoparticles with rodent serum proteins and their consequences in biokinetics.

When particles incorporated within a mammalian organism come into contact with body fluids they will bind to soluble proteins or those within cellular membranes forming what is called a protein corona. This binding process is very complex and highly dynamic due to the plethora of proteins with different affinities and fractions in different body fluids and the large variation of compounds and structures of the particle surface. Interestingly, in the case of nanoparticles (NP) this protein corona is well suited to provide a guiding vehicle of translocation within body fluids and across membranes. This NP translocation may subsequently lead to accumulation in various organs and tissues and their respective cell types that are not expected to accumulate such tiny foreign bodies. Because of this unprecedented NP accumulation, potentially adverse biological responses in tissues and cells cannot be neglected a priori but require thorough investigations. Therefore, we studied the interactions and protein binding kinetics of blood serum proteins with a number of engineered NP as a function of their physicochemical properties. Here we show by in vitro incubation tests that the binding capacity of different engineered NP (polystyrene, elemental carbon) for selected serum proteins depends strongly on the NP size and the properties of engineered surface modifications. In the following attempt, we studied systematically the effect of the size (5, 15, 80 nm) of gold spheres (AuNP), surface-modified with the same ionic ligand; as well as 5 nm AuNP with five different surface modifications on the binding to serum proteins by using proteomics analyses. We found that the binding of numerous serum proteins depended strongly on the physicochemical properties of the AuNP. These in vitro results helped us substantially in the interpretation of our numerous in vivo biokinetics studies performed in rodents using the same NP. These had shown that not only the physicochemical properties determined the AuNP translocation from the organ of intake towards blood circulation and subsequent accumulation in secondary organs and tissues but also the the transport across organ membranes depended on the route of AuNP application. Our in vitro protein binding studies support the notion that the observed differences in in vivo biokinetics are mediated by the NP protein corona and its dynamical change during AuNP translocation in fluids and across membranes within the organism.

Epidemiological study on human and canine leptospirosis in Central and North Kerala

Aim: The aim was to study the epidemiology of human and animal leptospirosis in Central and Northern Kerala, by isolation techniques and serology. Materials and Methods: Kidney tissues from 35 rodents (11 bandicoots and 24 rats), autopsy specimens from two canines, blood from 15 canines and 30 human beings were subjected to isolation trials for Leptospira. Sera from these animals and human beings were screened for leptospiral antibodies by microscopic agglutination test (MAT). Results: Leptospira could be isolated from human blood as well as from rodent kidney tissues. The MAT could detect the presence of leptospiral antibodies in 54.54% of human sera, 36.36% of dog sera and 21.42% of rodent sera. Pomona and Australis were the most predominant serovars detected in man, dog, and rodents. Tentative serotyping of the isolates by MAT revealed its identity as Leptospira interrogans serovar Pomona. Conclusion: Detection of common serovars of Leptospira in man and animals by serology as well as isolation reiterates the major role played by animals in the epidemiology of human leptospirosis.

Isolation and characterization of the circulating truncated form of PCSK9

Proprotein convertase subtilisin-kexin type 9 (PCSK9) is a secreted protein which regulates serum LDL cholesterol. It circulates in human and rodent serum in an intact form and a major truncated form. Previous in vitro studies involving the expression of human PCSK9 genetic variants and in vivo studies of furin knockout mice suggest that the truncated form is a furin cleavage product. However, the circulating truncated form of PCSK9 has not been isolated and characterized. Utilizing antibodies which bind to either the catalytic domain or the C-terminal domain of PCSK9, the truncated PCSK9 was isolated from serum. MS was used to determine that this form of PCSK9 is a product of in vivo cleavage at Arg218 resulting in pyroglutamic acid formation of the nascent N terminus corresponding to Gln219 of intact PCSK9. We also determined that the truncated PCSK9 in serum lacked the N-terminal segment which contains amino acids critical for LDL receptor binding. A truncated PCSK9, expressed and purified from HEK293 cells with identical composition as the circulating truncated protein, was not active in inhibition of LDL uptake by HepG2 cells. These studies provide a definitive characterization of the composition and activity of the truncated form of PCSK9 found in human serum.

Dual exposure of Rickettsia typhi and Orientia tsutsugamushi in the field-collected Rattus rodents from Thailand.

Field-collected rodents and fleas from ten provinces covering four regions of Thailand were investigated for possible rickettsial pathogen infections. The 257 trapped-rodents belonged to 12 species. Five species of Genus Rattus accounted for 93% of the total capture, of which Rattus exulans and Rattus norvegicus were the two major species caught. All flea specimens, removed from trapped rodents, were identified as Xenopsylla cheopis. The PCR technique was performed on ectoparasite specimens to detect the presence of murine typhus pathogen (Rickettsia typhi) and scrub typhus pathogen (Orientia tsutsugamushi). Thirteen flea specimens (2.6 %) were found to be positive for R. typhi but none for O. tsutsugamushi. An ELISA technique was used to detect the rodent's antibodies against R. typhi and O. tsutsugamushi. Sixty-one rodent serum samples (23.7%) were positive for R. typhi specific IgM, IgG, or both, while 47 of the samples (18.3%) were positive for O. tsutsugamushi. Twenty serum samples from R. norvegicus (7.8%) had detectable antibodies against both R. typhi and O. tsutsugamushi. Our findings revealed the existence of the dual infection of rickettsial pathogens in the same natural hosts.

Rickettsia bellii, Rickettsia amblyommii, and Laguna Negra hantavirus in an Indian reserve in the Brazilian Amazon.

BackgroundThe purpose of this study was to identify the presence of rickettsia and hantavirus in wild rodents and arthropods in response to an outbreak of acute unidentified febrile illness among Indians in the Halataikwa Indian Reserve, northwest of the Mato Grosso state, in the Brazilian Amazon. Where previously surveillance data showed serologic evidence of rickettsia and hantavirus human infection.MethodsThe arthropods were collected from the healthy Indian population and by flagging vegetation in grassland or woodland along the peridomestic environment of the Indian reserve. Wild rodents were live-trapped in an area bordering the reserve limits, due the impossibility of capturing wild animals in the Indian reserve. The wild rodents were identified based on external and cranial morphology and karyotype. DNA was extracted from spleen or liver samples of rodents and from invertebrate (tick and louse) pools, and the molecular characterization of the rickettsia was through PCR and DNA sequencing of fragments of two rickettsial genes (gltA and ompA). In relation to hantavirus, rodent serum samples were serologically screened by IgG ELISA using the Araraquara-N antigen and total RNA was extracted from lung samples of IgG-positive rodents. The amplification of the complete S segment was performed.ResultsA total of 153 wild rodents, 121 louse, and 36 tick specimens were collected in 2010. Laguna Negra hantavirus was identified in Calomys callidus rodents and Rickettsia bellii, Rickettsia amblyommii were identified in Amblyomma cajennense ticks.ConclusionsZoonotic diseases such as HCPS and spotted fever rickettsiosis are a public health threat and should be considered in outbreaks and acute febrile illnesses among Indian populations. The presence of the genome of rickettsias and hantavirus in animals in this Indian reserve reinforces the need to include these infectious agents in outbreak investigations of febrile cases in Indian populations.

Detection of coccidioidal antibodies in serum of a small rodent community in Baja California, Mexico

Coccidioidomycosis (Valley Fever) represents a serious threat to inhabitants of endemic areas of North America. Despite successful clinical isolations of the fungal etiological agent, Coccidioides spp., the screening of environmental samples has had low effectiveness, mainly because of the poor characterization of Coccidioides ecological niche. We explored Valle de las Palmas, Baja California, Mexico, a highly endemic area near the U.S.–Mexico border, where we previously detected Coccidioides via culture-independent molecular methods. By testing the serum from 40-trapped rodents with ELISA, we detected antibodies against Coccidioides in two species: Peromyscus maniculatus and Neotoma lepida. This study comprises the first report of wild rodent serum tested for coccidioidal antibodies, and sets the basis to analyze this pathogen in its natural environment and explore its potential ecological niche.

Entomological surveillance for rodent and their ectoparasites with special reference to potential of Scrub Typhus at Kolkata Port Trust (KPT), Kolkata (India)

Rodents are well established at port areas and their ectoparasite can be vectors of many diseases. Ships at seaport play an important role in spreading disease by transporting infected vectors. Plague, murine typhus, salmonellosis, trichinosis, leptospirosis and rat bite fever are known to be spread by rats. In view of the seriousness of the problem present study was undertaken to assess the prevalence of rodent – ectoparasite association at Kolkata Port Trust, Kolkata (India). A total of 442 rodent traps were laid and 17 rodents including two species of rodents Bandicota indica and Rattus rattus were collected with 3.8 trap positivity rate. Infestation rate of ectoprasites was 76.5%. Mites with 86.6% were the predominant ectoparisite retrieved from rodents followed by fleas and lice. The rodent ectoparasite index was 13.6 per rat. A total 78 vector larval trombiculide mite chigger ( Leptotrombidium deliense ) and 123 mesostigmatid mites ( Laelaps sp.) were collected. Chigger infestation rate was found to be 11.1 per rat. Passenger terminal was the only site where no mite could be retrieved. A total 26 fleas were retrieved giving an overall flea index as 1.53. The flea species collected from rodents were Xenopsylla cheopis and Ctenocephalides felis . Serological examination of rodent serum was found non- reactive for Orentia (Scrub typhus) and plague antibodies. Bacteriological investigation of organs impression smear and tissue of rodents showed no plague bacilli activity and isolation of Yersinia pestis. Result of the study suggests routine surveillance for rodent and their arthropods ectoparasite to apply appropriate control methods for controlling transmission and spreading of rodent borne diseases.

Development of a tick-borne encephalitis serodiagnostic ELISA using recombinant Fc-antigen fusion proteins

Current diagnostic tests for tick-borne encephalitis virus (TBEV) infections require high-biosafety facilities for antigen preparation and can cross-react with other flaviviruses. There is, therefore, a need to develop safe, inexpensive serodiagnostic tools with high specificity and sensitivity. In this study, a recombinant plasmid that expresses the membrane and envelope (E) proteins of TBEV fused to the Fc domain of rabbit IgG was constructed and expressed in mammalian cells. The E-Fc proteins were secreted as soluble homodimers, which retained reactivity with anti-TBEV and anti-rabbit IgG antibodies. The E-Fc proteins were then used to develop an enzyme-linked immunosorbent assay (ELISA) to detect TBEV antibodies in rodent and human sera. Compared with the neutralization test, the ELISA had over 90% sensitivity and specificity. In addition, the assay showed no cross-reactivity with Japanese encephalitis virus antibodies. These findings suggest that the E-Fc ELISA may be a useful tool for TBEV serodiagnosis.

Aging increases CCN1 expression leading to muscle senescence

Using microarray analysis, we found that aging sarcopenia is associated with a sharp increase in the mRNA of the matricellular protein CCN1 (Cyr61/CTGF/Nov). CCN1 mRNA was upregulated 113-fold in muscle of aged vs. young rats. CCN1 protein was increased in aging muscle in both rats (2.8-fold) and mice (3.8-fold). When muscle progenitor cells (MPCs) were treated with recombinant CCN1, cell proliferation was decreased but there was no change in the myogenic marker myoD. However, the CCN1-treated MPCs did express a senescence marker (SA-βgal). Interestingly, we found CCN1 increased p53, p16(Ink4A), and pRP (hypophosphorylated retinoblastoma protein) protein levels, all of which can arrest cell growth in MPCs. When MPCs were treated with aged rodent serum CCN1 mRNA increased by sevenfold and protein increased by threefold suggesting the presence of a circulating regulator. Therefore, we looked for a circulating regulator. Wnt-3a, a stimulator of CCN1 expression, was increased in serum from elderly humans (2.6-fold) and aged rodents (2.0-fold) compared with young controls. We transduced C2C12 myoblasts with wnt-3a and found that CCN1 protein was increased in a time- and dose-dependent manner. We conclude that in aging muscle, the circulating factor wnt-3a acts to increase CCN1 expression, prompting muscle senescence by activating cell arrest proteins.

Homology modeling, molecular docking, and molecular dynamics simulations elucidated α-fetoprotein binding modes

BackgroundAn important mechanism of endocrine activity is chemicals entering target cells via transport proteins and then interacting with hormone receptors such as the estrogen receptor (ER). α-Fetoprotein (AFP) is a major transport protein in rodent serum that can bind and sequester estrogens, thus preventing entry to the target cell and where they could otherwise induce ER-mediated endocrine activity. Recently, we reported rat AFP binding affinities for a large set of structurally diverse chemicals, including 53 binders and 72 non-binders. However, the lack of three-dimensional (3D) structures of rat AFP hinders further understanding of the structural dependence for binding. Therefore, a 3D structure of rat AFP was built using homology modeling in order to elucidate rat AFP-ligand binding modes through docking analyses and molecular dynamics (MD) simulations.MethodsHomology modeling was first applied to build a 3D structure of rat AFP. Molecular docking and Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) scoring were then used to examine potential rat AFP ligand binding modes. MD simulations and free energy calculations were performed to refine models of binding modes.ResultsA rat AFP tertiary structure was first obtained using homology modeling and MD simulations. The rat AFP-ligand binding modes of 13 structurally diverse, representative binders were calculated using molecular docking, (MM-GBSA) ranking and MD simulations. The key residues for rat AFP-ligand binding were postulated through analyzing the binding modes.ConclusionThe optimized 3D rat AFP structure and associated ligand binding modes shed light on rat AFP-ligand binding interactions that, in turn, provide a means to estimate binding affinity of unknown chemicals. Our results will assist in the evaluation of the endocrine disruption potential of chemicals.

Metabolic Phenotype of the Healthy Rodent Model Using In-Vial Extraction of Dried Serum, Urine, and Cerebrospinal Fluid Spots

High-throughput multiplatform metabolomics experiments are becoming an integral part of clinical and systems biology research. Such methods call for the adoption of robust sample storage and transport formats for small volumes of biofluids. One such format is the dried biofluid spot, which combines small volume requirements with easy portability. Here, we describe ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) metabolomics of dried rodent serum, urine, and cerebrospinal fluid spots. An in-vial extraction and UHPLC-MS analysis method was first developed and validated by fingerprinting two test fluids, rat serum and RPMI cell nutrient medium. Data for these extracts were compared in terms of (i) peak area measurements of selected features to assess reproducibility and (ii) total fingerprint variation after data pretreatment. Results showed that percentage peak area variation was found to range between 1.4 and 9.4% relative standard deviation (RSD) for a representative set of molecular features. Upon application of the method to spots bearing serum, urine or cerebrospinal fluid (CSF) from healthy rats and mice, a total of 1,182 and 2,309 reproducible molecular features were obtained in positive and negative ionization modes, respectively, of which 610 (positive) and 991 (negative) were found in both rats and mice. Feature matching was used to detect similarities and differences between biofluids, with the biggest overlap found between fingerprints obtained in urine and CSF. Our results thus demonstrate the potential of such direct fingerprinting of dried biofluid spots as a viable alternative to the use of small (10-15 μL) volumes of neat biofluids in animal studies.

Prevalence of antibody to hantaviruses in humans and rodents in the Caribbean region of Colombia determined using Araraquara and Maciel virus antigens

We tested sera from 286 agricultural workers and 322 rodents in the department of Córdoba, northeastern Colombia, for antibodies against two hantaviruses. The sera were analysed by indirect ELISA using the lysate of Vero E6 cells infected with Maciel virus (MACV) or the N protein of Araraquara virus (ARAV) as antigens for the detection of antibodies against hantaviruses. Twenty-four human sera were IgG positive using one or both antigens. We detected anti-MACV IgG antibodies in 10 sera (3.5%) and anti-ARAV antibodies in 21 sera (7.34%). Of the 10 samples that were positive for MACV, seven (70%) were cross-reactive with ARAV; seven of the 21 ARAV-positive samples were cross-reactive with MACV. Using an ARAV IgM ELISA, two of the 24 human sera (8.4%) were positive. We captured 322 rodents, including 210 Cricetidae (181 Zygodontomys brevicauda, 28 Oligoryzomys fulvescens and 1 Oecomys trinitatis), six Heteromys anomalus (Heteromyidae), one Proechimys sp. (Echimyidae) and 105 Muridae (34 Rattus rattus and 71 Mus musculus). All rodent sera were negative for both antigens. The 8.4% detection rate of hantavirus antibodies in humans is much higher than previously found in serosurveys in North America, suggesting that rural agricultural workers in northeastern Colombia are frequently exposed to hantaviruses. Our results also indicate that tests conducted with South American hantavirus antigens could have predictive value and could represent a useful alternative for the diagnosis of hantavirus infection in Colombia.

Blood-Borne Circadian Signal Stimulates Daily Oscillations in Actin Dynamics and SRF Activity

In peripheral tissues circadian gene expression can be driven either by local oscillators or by cyclic systemic cues controlled by the master clock in the brain's suprachiasmatic nucleus. In the latter case, systemic signals can activate immediate early transcription factors (IETFs) and thereby control rhythmic transcription. In order to identify IETFs induced by diurnal blood-borne signals, we developed an unbiased experimental strategy, dubbed Synthetic TAndem Repeat PROMoter (STAR-PROM) screening. This technique relies on the observation that most transcription factor binding sites exist at a relatively high frequency in random DNA sequences. Using STAR-PROM we identified serum response factor (SRF) as an IETF responding to oscillating signaling proteins present in human and rodent sera. Our data suggest that in mouse liver SRF is regulated via dramatic diurnal changes of actin dynamics, leading to the rhythmic translocation of the SRF coactivator Myocardin-related transcription factor-B (MRTF-B) into the nucleus.

Rat α-Fetoprotein Binding Affinities of a Large Set of Structurally Diverse Chemicals Elucidated the Relationships between Structures and Binding Affinities

Endocrine disrupting chemicals interfere with the endocrine system in animals, including humans, to exert adverse effects. One of the mechanisms of endocrine disruption is through the binding of receptors such as the estrogen receptor (ER) in target cells. The concentration of any chemical in serum is important for its entry into the target cells to bind the receptors. α-Fetoprotein (AFP) is a major transport protein in rodent serum that can bind with estrogens and thus change a chemical's availability for entrance into the target cell. Sequestration of an estrogen in the serum can alter the chemical's potential for disrupting estrogen receptor-mediated responses. To better understand endocrine disruption, we developed a competitive binding assay using rat amniotic fluid, which contains very high levels of AFP, and measured the binding to the rat AFP for 125 structurally diverse chemicals, most of which are known to bind ER. Fifty-three chemicals were able to bind the rat AFP in the assay, while 72 chemicals were determined to be nonbinders. Observations from closely examining the relationship between the binding data and structures of the tested chemicals are rationally explained in a manner consistent with proposed binding regions of rat AFP in the literature. The data reported here represent the largest data set of structurally diverse chemicals tested for rat AFP binding. The data assist in elucidating binding interactions and mechanisms between chemicals and rat AFP and, in turn, assist in the evaluation of the endocrine disrupting potential of chemicals.

Development of a serotyping enzyme-linked immunosorbent assay system based on recombinant truncated hantavirus nucleocapsid proteins for New World hantavirus infection

New World hantaviruses were divided into five groups based on the amino acid sequence variability of the internal variable region (around 230-302 amino acids) of hantavirus nucleocapsid protein (NP). Sin Nombre virus (SNV), Andes virus, Black Creek Canal virus (BCCV), Carrizal virus (CARV) and Cano Delgadito virus belong to groups 1, 2, 3, 4 and 5, respectively. Patient and rodent sera were serotyped successfully by an enzyme-linked immunosorbent assay (ELISA) with recombinant truncated NP lacking 99 N-terminal amino acids (trNP100) of SNV, CARV and BCCV. The trNP100 of BCCV showed lower reactivity to heterologous sera. In contrast, whole recombinant NP antigens detected both homologous and heterologous antibodies equally. The results together with results of a previous study suggest that trNP100 can distinguish infections among viruses in groups 1, 2, 3 and 4 of New World hantaviruses. The serotyping ELISA with trNP100 is useful for epidemiological surveillance in humans and rodents.

Prevalence of haemoparasites, leptospires and coccobacilli with potential for human infection in the blood of rodents and shrews from selected localities in Tanzania, Namibia and Swaziland

The prevalence of haemoparasites, leptospirosis and Yersinia pestis was investigated in rodents and shrews from Tanzania, Namibia and Swaziland. Blood smears originating from rodents and shrews from the three countries indicated the presence of Trypanosoma lewisi (72.7%; n =950), Bacillus spp. (25.6%; n =950), Borrelia sp. (0.01%; n =950) and bipolar coccobacilli (0.01%; n =950). The blood smears from Namibia (n =26) had no haemoparasites while only 1.33% (n =75) of those from Swaziland showed presence of T. lewisi. Leptospira interrogans was found in rodent blood sera from Tanzania in the following serogroup proportions (n =350): Icterohaemorrhagiae (10.29%), Pomona (2.86%), Hardjo (1.14%), Bullum (0.86%), Grippotyphosa (1.43%) and Canicola (1.14%). Serodiagnosis of antibodies against the F1 antigen of Y. pestis using the enzyme linked immunosorbent assay (ELISA) was negative for all the serum samples from central Tanzania, while two samples of serum from two species of rodents, Rhabdomys pumilio and Gerbilliscus leucogaster, collected in the Kavango Region of Namibia were positive. These results suggest an enzootic plague activity in this region in Namibia. It is concluded that zoonotic agents, that are infectious to humans, are prevalent in rodents and shrews in the three countries, and that local communities should apply rodent control measures to reduce the risk of human infections.

Prevalence of Haemoparasites, Leptospires and Coccobacilli with Potential for Human Infection in the Blood of Rodents and Shrews from Selected Localities in Tanzania, Namibia and Swaziland†

The prevalence of haemoparasites, leptospirosis and Yersinia pestis was investigated in rodents and shrews from Tanzania, Namibia and Swaziland. Blood smears originating from rodents and shrews from the three countries indicated the presence of Trypanosoma lewisi (72.7%; n =950), Bacillus spp. (25.6%; n =950), Borrelia sp. (0.01%; n =950) and bipolar coccobacilli (0.01%; n =950). The blood smears from Namibia (n =26) had no haemoparasites while only 1.33% (n =75) of those from Swaziland showed presence of T. lewisi. Leptospira interrogans was found in rodent blood sera from Tanzania in the following serogroup proportions (n =350): Icterohaemorrhagiae (10.29%), Pomona (2.86%), Hardjo (1.14%), Bullum (0.86%), Grippotyphosa (1.43%) and Canicola (1.14%). Serodiagnosis of antibodies against the F1 antigen of Y. pestis using the enzyme linked immunosorbent assay (ELISA) was negative for all the serum samples from central Tanzania, while two samples of serum from two species of rodents, Rhabdomys pumilio and Gerbilliscus leucogaster, collected in the Kavango Region of Namibia were positive. These results suggest an enzootic plague activity in this region in Namibia. It is concluded that zoonotic agents, that are infectious to humans, are prevalent in rodents and shrews in the three countries, and that local communities should apply rodent control measures to reduce the risk of human infections.

Serological Evidence of Tick-Borne Encephalitis Virus Infection in Rodents Captured at Four Sites in Switzerland

In a previous study, the presence of tick-borne encephalitis virus (TBEV) in questing Ixodes ricinus L. ticks and in field derived ticks that engorged on small mammals (n = 9,986) was investigated at four sites located in a TBE area in Switzerland. Two of these sites were already recognized as TBE foci (Thun and Belp) and the screening of ticks revealed the presence of TBEV in ticks at a third site, Kiesen, but not at the fourth one, Trimstein. The aim here was to test another approach to detect TBE endemic areas. Sera from 333 small mammals (Apodemus flavicollis, A. sylvaticus, Myodes glareolus) captured in 2006 and 2007 at the four sites were examined for the presence of antibodies against TBEV using immunofluorescence and avidity tests. Overall the prevalence of antibodies against TBEV in rodents reached 3.6% (12/333). At two sites known as TBE foci, Thun and Belp, anti-TBEV antibodies were detected in 9.9% (9/91) and 1.6% (1/63) of rodent sera, respectively. At the third site, Kiesen, recently identified as a TBE focus by the detection of TBEV in ticks, anti-TBEV antibodies were detected in 1.8% (2/113) of rodent sera. Finally, at Trimstein, none of the examined rodent sera had antibodies against TBEV (0/66). This study shows another approach to detect TBE foci by testing antibodies in small mammal sera that is less time-consuming and less expensive than molecular tools.