Animal infection studies of two recently discovered African bat paramyxoviruses, Achimota 1 and Achimota 2

Bats are implicated as the natural reservoirs for several highly pathogenic viruses that can infect other animal species, including man. Here, we investigate the potential for two recently discovered bat rubulaviruses, Achimota virus 1 (AchPV1) and Achimota virus 2 (AchPV2), isolated from urine collected under urban bat (Eidolon helvum) roosts in Ghana, West Africa, to infect small laboratory animals. AchPV1 and AchPV2 are classified in the family Paramyxoviridae and cluster with other bat derived zoonotic rubulaviruses (i.e. Sosuga, Menangle and Tioman viruses). To assess the susceptibility of AchPV1 and AchPV2 in animals, infection studies were conducted in ferrets, guinea pigs and mice. Seroconversion, immunohistological evidence of infection, and viral shedding were identified in ferrets and guinea pigs, but not in mice. Infection was associated with respiratory disease in ferrets. Viral genome was detected in a range of tissues from ferrets and guinea pigs, however virus isolation was only achieved from ferret tissues. The results from this study indicate Achimota viruses (AchPVs) are able to cross the species barrier. Consequently, vigilance for infection with and disease caused by these viruses in people and domesticated animals is warranted in sub-Saharan Africa and the Arabian Peninsula where the reservoir hosts are present.

Experimental Hendra virus infection of dogs: virus replication, shedding and potential for transmission

OBJECTIVE

Characterisation of experimental Hendra virus (HeV) infection in dogs and assessment of associated transmission risk.

METHODS

Beagle dogs were exposed oronasally to Hendra virus/Australia/Horse/2008/Redlands or to blood collected from HeV-infected ferrets. Ferrets were exposed to oral fluids collected from dogs after canine exposure to HeV. Observations made and samples tested post-exposure were used to assess the clinical course and replication sites of HeV in dogs, the infectivity for ferrets of canine oral fluids and features of HeV infection in dogs following contact with infective blood.

RESULTS

Dogs were reliably infected with HeV and were generally asymptomatic. HeV was re-isolated from the oral cavity and virus clearance was associated with development of virus neutralising antibody. Major sites of HeV replication in dogs were the tonsils, lower respiratory tract and associated lymph nodes. Virus replication was documented in canine kidney and spleen, confirming a viraemic phase for canine HeV infection and suggesting that urine may be a source of infectious virus. Infection was transmitted to ferrets via canine oral secretions, with copy numbers for the HeV N gene in canine oral swabs comparable to those reported for nasal swabs of experimentally infected horses.

CONCLUSION

HeV is not highly pathogenic for dogs, but their oral secretions pose a potential transmission risk to people. The time-window for transmission risk is circumscribed and corresponds to the period of acute infection before establishment of an adaptive immune response. The likelihood of central nervous system involvement in canine HeV infection is unclear, as is any long-term consequence.

Efficacy of a specific polyclonal equine F(ab')2 against avian influenza (H5N1) in ferrets: synergy with oseltamivir

Aim: Current therapies against avian influenza (H5N1) provide limited clinical benefit. FBF-001 is a highly purified equine polyclonal immunoglobulin fragment against H5N1. Methods: Using a ferret model of severe acute H5N1 infection, we assessed FBF-001 when administered on the same day or 1 day after viral challenge, in comparison with oseltamivir therapy. Results: Untreated animals died 2–3 days after challenge. FBF-001 prevented most severe illness and reduced nasal viral load, with best efficacy when administered on the day of viral challenge. Oseltamivir and FBF-001 had synergistic impact on survival. Conclusion: FBF-001 prevented severe consequences of lethal H5N1 challenge in ferrets by controlling viral replication, an effect synergistic to oseltamivir. FBF-001 has recently been granted EMA orphan drug status.

The Nature of Exposure Drives Transmission of Nipah Viruses from Malaysia and Bangladesh in Ferrets

Person-to-person transmission is a key feature of human Nipah virus outbreaks in Bangladesh. In contrast, in an outbreak of Nipah virus in Malaysia, people acquired infections from pigs. It is not known whether this important epidemiological difference is driven primarily by differences between NiV Bangladesh (NiV-BD) and Malaysia (NiV-MY) at a virus level, or by environmental or host factors. In a time course study, ferrets were oronasally exposed to equivalent doses of NiV-BD or NiV-MY. More rapid onset of productive infection and higher levels of virus replication in respiratory tract tissues were seen for NiV-BD compared to NiV-MY, corroborating our previous report of increased oral shedding of NiV-BD in ferrets and suggesting a contributory mechanism for increased NiV-BD transmission between people compared to NiV-MY. However, we recognize that transmission occurs within a social and environmental framework that may have an important and differentiating role in NiV transmission rates. With this in mind, ferret-to-ferret transmission of NiV-BD and NiV-MY was assessed under differing viral exposure conditions. Transmission was not identified for either virus when naïve ferrets were cohoused with experimentally-infected animals. In contrast, all naïve ferrets developed acute infection following assisted and direct exposure to oronasal fluid from animals that were shedding either NiV-BD or NiV-MY. Our findings for ferrets indicate that, although NiV-BD may be shed at higher levels than NiV-MY, transmission risk may be equivalently low under exposure conditions provided by cohabitation alone. In contrast, active transfer of infected bodily fluids consistently results in transmission, regardless of the virus strain. These observations suggest that the risk of NiV transmission is underpinned by social and environmental factors, and will have practical implications for managing transmission risk during outbreaks of human disease.

Evaluation of a mouse model for the West Nile virus group for the purpose of determining viral pathotypes

West Nile virus (WNV; family Flaviviridae; genus Flavivirus) group members are an important cause of viral meningoencephalitis in some areas of the world. They exhibit marked variation in pathogenicity, with some viral lineages (such as those from North America) causing high prevalence of severe neurological disease, whilst others (such as Australian Kunjin virus) rarely cause disease. The aim of this study was to characterize WNV disease in a mouse model and to elucidate the pathogenetic features that distinguish disease variation. Tenfold dilutions of five WNV strains (New York 1999, MRM16 and three horse isolates of WNV-Kunjin: Boort and two isolates from the 2011 Australian outbreak) were inoculated into mice by the intraperitoneal route. All isolates induced meningoencephalitis in different proportions of infected mice. WNVNY99 was the most pathogenic, the three horse isolates were of intermediate pathogenicity and WNVKUNV-MRM16 was the least, causing mostly asymptomatic disease with seroconversion. Infectivity, but not pathogenicity, was related to challenge dose. Using cluster analysis of the recorded clinical signs, histopathological lesions and antigen distribution scores, the cases could be classified into groups corresponding to disease severity. Metrics that were important in determining pathotype included neurological signs (paralysis and seizures), meningoencephalitis, brain antigen scores and replication in extra-neural tissues. Whereas all mice infected with WNVNY99 had extra-neural antigen, those infected with the WNV-Kunjin viruses only occasionally had antigen outside the nervous system. We conclude that the mouse model could be a useful tool for the assessment of pathotype for WNVs.

Hendra virus vaccine, a one health approach to protecting horse, human, and environmental health

In recent years, the emergence of several highly pathogenic zoonotic diseases in humans has led to a renewed emphasis on the interconnectedness of human, animal, and environmental health, otherwise known as One Health. For example, Hendra virus (HeV), a zoonotic paramyxovirus, was discovered in 1994, and since then, infections have occurred in 7 humans, each of whom had a strong epidemiologic link to similarly affected horses. As a consequence of these outbreaks, eradication of bat populations was discussed, despite their crucial environmental roles in pollination and reduction of the insect population. We describe the development and evaluation of a vaccine for horses with the potential for breaking the chain of HeV transmission from bats to horses to humans, thereby protecting horse, human, and environmental health. The HeV vaccine for horses is a key example of a One Health approach to the control of human disease.

Recombinant Hendra viruses expressing a reporter gene retain pathogenicity in ferrets

Background

Hendra virus (HeV) is an Australian bat-borne zoonotic paramyxovirus that repeatedly spills-over to horses causing fatal disease. Human cases have all been associated with close contact with infected horses.

Methods

A full-length antigenome clone of HeV was assembled, a reporter gene (GFP or luciferase) inserted between the P and M genes and transfected to 293T cells to generate infectious reporter gene-encoding recombinant viruses. These viruses were then assessed in vitro for expression of the reporter genes. The GFP expressing recombinant HeV was used to challenge ferrets to assess the virulence and tissue distribution by monitoring GFP expression in infected cells.

Results

Three recombinant HeV constructs were successfully cloned and rescued; a wild-type virus, a GFP-expressing virus and a firefly luciferase-expressing virus. In vitro characterisation demonstrated expression of the reporter genes, with levels proportional to the initial inoculum levels. Challenge of ferrets with the GFP virus demonstrated maintenance of the fatal phenotype with disease progressing to death consistent with that observed previously with the parental wild-type isolate of HeV. GFP expression could be observed in infected tissues collected from animals at euthanasia.

Conclusions

Here, we report on the first successful rescue of recombinant HeV, including wild-type virus and viruses expressing two different reporter genes encoded as an additional gene cassette inserted between the P and M genes. We further demonstrate that the GFP virus retained the ability to cause fatal disease in a well-characterized ferret model of henipavirus infection despite the genome being an extra 1290 nucleotides in length.

Go with the flow: an updated tool for detecting molecules

In the early 1970, researchers at Los Alamos National Laboratories developed the flow cytometer, a device that allows for the identification of unknown cells. In a flow cytometer, a single-cell suspension is passed in a continuous flow through a laser beam, with each cell scattering the light in a characteristic manner. A few years ago, researchers at Los Alamos began another project, refining the capabilities of the flow cytometer so that it could analyze not a single cell but a single molecule, allowing scientists to study bacteria at the molecular level, differentiating between individual strains more quickly and with greater accuracy than before. The new flow cytometer shows great promise in a variety of fields where single-molecule study would be valuable, such as genomics and disease transmission.

Lipid lather removes metals

Metal contamination has been linked to birth defects, cancer, skin lesions, retardation, learning disabilities, liver and kidney damage, and a host of other maladies, and the United States alone will spend some $7 trillion over the next five years or so to clean up sites contaminated with metals. Until recently, there have only been a few time-consuming, costly methods for dealing with metal contamination in soils, but research developed at the University of Arizona uses biosurfactants, lipids that form emulsions between liquids of different polarities, to virtually "wash" metals out of contaminated soil. Lab tests show that 80-100% of single metals including cadmium and lead can be removed through the use of environmentally benign biosurfactants.

The trickle-down theory of cleaner air

The 1990 Clean Air Act Amendments prompted an increased urgency to find new ways to treat airstreams containing volatile organic compounds, which affect the nitrogen photolytic cycle and help produce ground-level ozone, hazardous air pollutants, and odorous air emissions such as hydrogen sulfide. Scientists at the New Jersey company Envirogen have adapted traditional biofiltration technology to perform airborne waste stream cleanup. Preliminary research on pollutants such as phenol, methylene chloride, benzene, and toluene indicates that Envirogen's biotrickling filter may remove an average of about 94% of total hazardous air pollutants. Scientists are working to identify microbes that will clean up more stubborn pollutants.

Plasma jet takes off

Thanks to a series of joint research projects by Los Alamos National Laboratory, Beta Squared of Allen, Texas, and the University of California at Los Angeles, there is now a more environmentally sound method for cleaning semiconductor chips that may also be effective in cleaning up chemical, bacterial, and nuclear contaminants. The Atmospheric Pressure Plasma Jet uses a type of ionized gas called plasma to clean up contaminants by binding to them and lifting them away. In contrast to the corrosive acids and chemical solvents traditionally used to clean semiconductor chips, the jet oxidizes contaminants, producing only benign gaseous by-products such as oxygen and carbon dioxide. The new technology is also easy to transport, cleans thoroughly and quickly, and presents no hazards to its operators.

Palm readings

Scientists are taking technology in common laboratory usage for more than 15 years and adapting it in ways that may, quite literally, bring the laboratory into the field. The technology is known as surface plasmon resonance (SPR), and a team of scientists has taken a sensing unit that was once the size of an old-fashioned console television and shrunken it down into a handheld unit no bigger than a conductor's baton.

Fat-soluble vitamin concentration in chronic alcohol-induced pancreatitis. Relationship with steatorrhea

In order to study the fat-soluble vitamin concentration of patients with chronic alcohol-induced pancreatitis (CAIP) we measured vitamins A and E, total lipids, and retinol-binding protein (RBP) in the plasma of 44 patients with CAIP and 83 controls (44 healthy controls; 39 Crohn's disease patients). Mean plasma vitamin E and vitamin E/total lipid ratio were significantly lower in CAIP when compared with either control or Crohn's disease groups. A low vitamin E/total lipid ratio was found in 75% of CAIP patients (91% with steatorrhea) and a ratio less than 1.0 was virtually 100% predictive of steatorrhea. The mean plasma vitamin A level for the CAIP group was significantly lower (overall 16%, 38% with steatorrhea) than in controls. Patients with CAIP show subnormal plasma levels vitamin E more often as compared to vitamin A. Further, the plasma vitamin E/total lipids ratio may be a sensitive and practical means in the detection and follow-up of steatorrhea in these patients.