Cross host transmission in the emergence of MERS coronavirus

Coronaviruses (CoVs) able to infect humans emerge through cross-host transmission from animals. There is substantial evidence that the recent Middle East respiratory syndrome (MERS)-CoV outbreak is fueled by zoonotic transmission from dromedary camels. This is largely based on the fact that closely related viruses have been isolated from this but not any other animal species. Given the widespread geographical distribution of dromedaries found seropositive for MERS-CoV, continued transmission may likely occur in the future. Therefore, a further understanding of the cross host transmission of MERS-CoV is needed to limit the risks this virus poses to man

Effect of temperature and salinity on the infectivity pattern of white spot syndrome virus (WSSV) in giant tiger shrimp Penaeus monodon (Fabricius, 1837)

White spot disease (WSD) caused by the lethal white spot syndrome virus (WSSV) continues to be the major cause of mortality among farmed tiger shrimp in India and elsewhere, resulting in an annual loss of about 4-6 billion US$. Among the environmental variables, temperature and salinity of the rearing water are considered to be major triggering factors for white spot disease outbreak. In order to characterise the effect of salinity and temperature on the pathogenecity of WSSV infection in giant tiger shrimp Penaeus monodon, a laboratory challenge study was conducted at different levels of temperature (16, 25, 27, 28, 30, 32 and 36 ºC) and salinity (0.5, 5, 10, 15, 30 and 45 g l-1) with virulent white spot syndrome virus. Significant influence of temperature (p<0.05) on the percentage mortality and time until death of shrimp affected by the virus was observed, whereas salinity did not show any effect. Significantly higher survival rate was recorded in animals exposed at 32 ºC (37%) and 36 ºC (14%), 21 days post-challenge (dpc). All the shrimp challenged at other temperature levels, however, died after 21 dpc. These results demonstrated preference of WSSV for lower temperatures and higher survival in temperature ranges of 32 ºC to 36 ºC. The present observation may help to develop a management option to control the WSSV inflicted mortalities by selecting favorable hyperthermic rearing conditions for the shrimp

Incidence of white muscle disease, a viral like disease associated with mortalities in hatchery reared postlarvae of the giant freshwater prawn Macrobrachium rosenbergii (De Man) from the south east coast of India

Incidence of post-larval mortalities of 30- 100% was reported from commercial freshwater prawn Macrobrachium rosenbergii (De Man) hatcheries in Andhra Pradesh and Tamil Nadu (south-eastern states of India) since 2001. Infec ted postlarvae (PL) exhibited clinical symptoms with lethargy, anorexia and whitening of abdominal muscles and the disease was identified as white muscle disease (WMD)

Skin mucus of Cyprinus carpio inhibits cyprinid herpesvirus 3 binding to epidermal cells

Cyprinid herpesvirus 3 (CyHV-3) is the aetiological agent of a mortal and highly contagious disease in common and koi carp. The skin is the major portal of entry of CyHV-3 in carp after immersion in water containing the virus. In the present study, we used in vivo bioluminescence imaging to investigate the effect of skin mucus removal and skin epidermis lesion on CyHV-3 entry. Physical treatments inducing removal of the mucus up to complete erosion of the epidermis were applied on a defined area of carp skin just before inoculation by immersion in infectious water. CyHV-3 entry in carp was drastically enhanced on the area of the skin where the mucus was removed with or without associated epidermal lesion. To investigate whether skin mucus inhibits CyHV-3 binding to epidermal cells, tail fins with an intact mucus layer or without mucus were inoculated ex vivo. While electron microscopy examination revealed numerous viral particles bound on the fins inoculated after mucus removal, no particle could be detected after infection of mucus-covered fins. Finally, anti-CyHV-3 neutralising activity of mucus extract was tested in vitro. Incubation of CyHV-3 with mucus extract reduced its infectivity in a dose dependent manner. The present study demonstrates that skin mucus removal and epidermal lesions enhance CyHV-3 entry in carp. It highlights the role of fish skin mucus as an innate immune protection against viral epidermal entry

Proteomic and functional analyses of the virion transmembrane proteome of cyprinid herpesvirus 3

Virion transmembrane proteins (VTPs) mediate key functions in the herpesvirus infectious cycle. Cyprinid herpesvirus 3 (CyHV-3) is the archetype of fish alloherpesviruses. The present study was devoted to CyHV-3 VTPs. Using mass spectrometry approaches, we identified 16 VTPs of the CyHV-3 FL strain. Mutagenesis experiments demonstrated that eight of these proteins are essential for viral growth in vitro (ORF32, ORF59, ORF81, ORF83, ORF99, ORF106, ORF115, and ORF131), and eight are non-essential (ORF25, ORF64, ORF65, ORF108, ORF132, ORF136, ORF148, and ORF149). Among the non-essential proteins, deletion of ORF25, ORF132, ORF136, ORF148, or ORF149 affects viral replication in vitro, and deletion of ORF25, ORF64, ORF108, ORF132, or ORF149 impacts plaque size. Lack of ORF148 or ORF25 causes attenuation in vivo to a minor or major extent, respectively. The safety and efficacy of a virus lacking ORF25 were compared to those of a previously described vaccine candidate deleted for ORF56 and ORF57 (Δ56-57). Using quantitative PCR, we demonstrated that the ORF25 deleted virus infects fish through skin infection and then spreads to internal organs as reported previously for the wild-type parental virus and the Δ56-57 virus. However, compared to the parental wild-type virus, the replication of the ORF25 deleted virus was reduced in intensity and duration to levels similar to those observed for the Δ56-57 virus. Vaccination of fish with a virus lacking ORF25 was safe but had low efficacy at the doses tested. This characterization of the virion transmembrane proteome of CyHV-3 provides a firm basis for further research on alloherpesvirus VTPs. IMPORTANCE Virion transmembrane proteins play key roles in the biology of herpesviruses. Cyprinid herpesvirus 3 (CyHV-3) is the archetype of fish alloherpesviruses and the causative agent of major economic losses in common and koi carp worldwide. In this study of the virion transmembrane proteome of CyHV-3, the major findings were: (i) the FL strain encodes 16 virion transmembrane proteins; (ii) eight of these proteins are essential for viral growth in vitro; (iii) seven of the non-essential proteins affect viral growth in vitro, and two affect virulence in vivo; and (iv) a mutant lacking ORF25 is highly attenuated but induces moderate immune protection. This study represents a major breakthrough in understanding the biology of CyHV-3 and will contribute to the development of prophylactic methods. It also provides a firm basis for the further research on alloherpesvirus virion transmembrane proteins

Електрофізичні властивості системи політетрафторетилен – вуглецеві нанотрубки

Проведено дослідження комплексної діелектричної проникності та електропровідності в надвисокочастотному діапазоні (9 ГГц) і на низьких частотах (0,1; 1 та 10 кГц) двох систем політетрафторетилен – багатошарові вуглецеві нанотрубки з вихідними та диспергованими у водному середовищі . Введення диспергованих нанотрубок в полімер знижує поріг перколяції з 4,5 % до 2,6 % (мас.) за рахунок рівномірного розподілу наповнювача у полімері, що призводить до зростання міжфазної поверхні взаємодії полімер – вуглецеві нанотрубки, яка проявляється в збільшенні значень дійсної та уявної складової комплексної діелектричної проникності.Проведены исследования комплексной диэлектрической проницаемости и электропроводности в сверхвысокочастотном диапазоне (9 ГГц) и на низких частотах (0,1; 1; 10 кГц) двух систем политетрафторэтилен–многослойные углеродные нанотрубки с исходными и диспергированными у водной среде. Введение диспергированных нанотрубок в полимер снижает порог перколяции с 4,5% до 2,6 % (масс.) за счет равномерного распределения наполнителя в полимере, что приводит к возрастанию межфазной поверхности взаимодействия полимер – углеродные нанотрубки, которая проявляется в увеличении значений действительной и мнимой составляющей комплексной диэлектрической проницаемости.Complex dielectric permeability and conductivity of two systems, namely polytetrafluorethylene – intact carbon nanotubes and polytetrafluorethylene – carbon nanotubes dispersed in aqueous media, has been studied in super high-frequency range (9 GHz) and at low frequencies (0,1; 1 and 10 kHz). Doping of the polymer with the dispersed nanotubes decreases percolation threshold (limit ) from 4,5 wt. % to 2,6 wt. % due to uniform distribution of the filler in the polymer. This results to increase of interface interaction polymer - carbon nanotubes that is demonstrated by increase of value of real and imaginary component of complex dielectric permeability

Feeding Cyprinus carpio with infectious materials mediates cyprinid herpesvirus 3 entry through infection of pharyngeal periodontal mucosa

Cyprinid herpesvirus 3 (CyHV-3), also known as Koi herpesvirus, is the etiological agent of a mortal disease in common and koi carp. Recently, we investigated the entry of CyHV-3 in carp using bioluminescence imaging and a CyHV-3 recombinant strain expressing luciferase (LUC). We demonstrated that the skin is the major portal of entry after inoculation of carp by immersion in water containing CyHV-3. While this model of infection mimics some natural conditions in which infection takes place, other epidemiological conditions could favour entry of virus through the digestive tract. Here, we investigated whether ingestion of infectious materials mediates CyHV-3 entry through the digestive tract. Carp were fed with materials contaminated with the CyHV-3 LUC recombinant (oral contamination) or immersed in water containing the virus (contamination by immersion). Bioluminescence imaging analyses performed at different times post-infection led to the following observations: (i) the pharyngeal periodontal mucosa is the major portal of entry after oral contamination, while the skin is the major portal of entry after contamination by immersion. (ii) Both modes of inoculation led to the spreading of the infection to the various organs tested. However, the timing and the sequence in which some of the organs turned positive were different between the two modes of inoculation. Finally, we compared the disease induced by the two inoculation modes. They led to comparable clinical signs and mortality rate. The results of the present study suggest that, based on epidemiological conditions, CyHV-3 can enter carp either by skin or periodontal pharyngeal mucosal infection

Involvement of Enterobacter cloacae in the mortality of the fish, Mugil cephalus

Enterobacter cloacae, an enteric bacterium that belongs to the family Enterobacteriaceae, is widely distributed in nature. It is found in faeces of humans and animals, water, soil, plants, plant materials, insects and dairy product

Identification and Characterization of Two Novel Viruses in Ocular Infections in Reindeer

A thorough understanding of virus diversity in wildlife provides epidemiological baseline information about pathogens. In this study, eye swab samples were obtained from semi-domesticated reindeer (Rangifer tarandus tarandus) in Norway during an outbreak of infectious eye disease, possibly a very early stage of infectious keratoconjunctivitis (IKC). Large scale molecular virus screening, based on host nucleic acid depletion, sequence-independen