Virucidal efficacy of four new disinfectants

Calicivirus Infection in Cats

Feline calicivirus (FCV) is a common pathogen in domestic cats that is highly contagious, resistant to many disinfectants and demonstrates a high genetic variability. FCV infection can lead to serious or even fatal diseases. In this review, the European Advisory Board on Cat Diseases (ABCD), a scientifically independent board of experts in feline medicine from 11 European countries, presents the current knowledge of FCV infection and fills gaps with expert opinions. FCV infections are particularly problematic in multicat environments. FCV-infected cats often show painful erosions in the mouth and mild upper respiratory disease and, particularly in kittens, even fatal pneumonia. However, infection can be associated with chronic gingivostomatitis. Rarely, highly virulent FCV variants can induce severe systemic disease with epizootic spread and high mortality. FCV can best be detected by reverse-transcriptase PCR. However, a negative result does not rule out FCV infection and healthy cats can test positive. All cats should be vaccinated against FCV (core vaccine); however, vaccination protects cats from disease but not from infection. Considering the high variability of FCV, changing to different vaccine strain(s) may be of benefit if disease occurs in fully vaccinated cats. Infection-induced immunity is not life-long and does not protect against all strains; therefore, vaccination of cats that have recovered from caliciviral disease is recommended.

Efficacy of physical and chemical treatments on the inactivation of bovine leukosis virus present in milk

PURPOSE

The objective of the present study was to evaluate the efficacy of pasteurization, freezing, the addition of formaldehyde and peroxymonosulfate on the inactivation of the bovine leukemia virus (BLV) present in milk.

MATERIALS AND METHODS

A sheep bioassay was carried out in 40 sheep, which were intraperitoneally inoculated with leukocytes from milk infected by the BLV previously treated with one of the virus inactivation methods. Five study groups were evaluated: (1) control group: milk without previous treatment, (2) pasteurization group: milk treated by pasteurization, (3) freezing group: milk treated by freezing for 36 hours, (4) formaldehyde group: 0.1% formaldehyde, and (5) peroxymonosulfate group: 0.05% peroxymonosulfate. The inoculated animals were followed for 10 weeks.

RESULTS

At week 10 post-inoculation, all the animals (8/8) of the control group and the peroxymonosulfate group were seropositive to BLV, while no animals were seropositive (0/8) to BLV in the remaining three groups. Statistically significant differences were found between the pasteurization, freezing and formaldehyde groups with respect to the control (p<0.001) and peroxymonosulfate groups (p<0.001).

CONCLUSION

The results indicate that pasteurization, freezing and formaldehyde processes are efficient in inactivating the BLV and can be used in milk to prevent the transmission of the virus.

Inactivation of Adeno-Associated Viral Vectors by Oxidant-Based Disinfectants

Adeno-associated viral (AAV) vectors are becoming increasingly popular in basic research as well as in clinical gene therapy. Due to its exceptional resistance against physical and chemical stress, however, the increasing use of AAV in laboratories and clinics around the globe raises safety concerns. Proper decontamination of tools and surfaces based on reliable AAV inactivation is crucial to prevent uncontrolled vector dissemination. Although recommended for AAV decontamination, sodium hypochlorite is not compatible with all surfaces found in the laboratory or clinical environment due to its corrosive nature. We, therefore, compared 0.5% sodium hypochlorite to 0.25% peracetic acid (PAA), a second substance declared effective, and to three less aggressive, commonly available alternative disinfectants 70% ethanol, 1.5% hydrogen peroxide, and 0.45% potassium peroxymonosulfate. The impact of all five disinfectants on virus capsid integrity, viral genome integrity, and infectivity upon different exposure times was tested on AAV2 and AAV5, two serotypes with highly different thermostability. While sodium hypochlorite, potassium peroxymonosulfate, and PAA successfully inactivated AAV2 after 1, 5, and 30 min, respectively, ethanol and hydrogen peroxide did not show significant effects on AAV2 even after exposure for 30 min. For AAV5, only sodium hypochlorite and potassium peroxymonosulfate proved efficient capsid and genome denaturation after incubation for 1 and 30 min, respectively. Consequently, ethanol or hydrogen peroxide should not be considered for routine laboratory or clinical use, while 0.45% potassium peroxymonosulfate and 0.5% sodium hypochlorite represent suitable and broadly effective disinfectants for AAV inactivation.

Beyond personal protective equipment: adjunctive methods for control of healthcare-associated respiratory viral infections

PURPOSE OF REVIEW

Prevention of nosocomial transmission of respiratory viruses is a priority in all healthcare settings and often achieved with the use of personal protective equipment. Several adjunctive infection prevention methods are in common use but their effectiveness in reducing healthcare-associated respiratory viral infections is unclear. In this review, recent advances regarding the effectiveness of several adjunctive infection prevention methods to reduce healthcare-associated respiratory viral infections are discussed.

RECENT FINDINGS

Training and education on hand hygiene guidelines, mandatory influenza vaccination for healthcare personnel, access to paid sick leave to reduce ill presenteeism, cohorting of patients with the same infection or clinical syndrome, neuraminidase inhibitor chemoprophylaxis during influenza outbreaks, and enhanced visitor restrictions in pediatric hospitals all have shown some degree of effectiveness in observational or quasi-experimental studies.

SUMMARY

Most of the studies evaluating the effect of adjunctive infection prevention methods on healthcare-associated respiratory viral infections are observational or quasi-experimental and are often combined with other interventions. Therefore, it is difficult to determine the precise effectiveness or efficacy of these interventions and more controlled trials are needed. Multimodal infection prevention policies are likely to be most effective in reducing healthcare-associated respiratory viral infections.

Factors affecting stability and infectivity of SARS-CoV-2

BACKGROUND

In late 2019, a novel human coronavirus - severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) - emerged in Wuhan, China. This virus has caused a global pandemic involving more than 200 countries. SARS-CoV-2 is highly adapted to humans and readily transmits from person-to-person.

AIM

To investigate the infectivity of SARS-CoV-2 under various environmental and pH conditions. The efficacies of various laboratory virus inactivation methods and home disinfectants against SARS-CoV-2 were investigated.

METHODS

The residual virus in dried form or in solution was titrated on to Vero E6 cells on days 0, 1, 3, 5 and 7 after incubation at different temperatures. Viral viability was determined after treatment with various disinfectants and pH solutions at room temperature (20-25^oC).

FINDINGS

SARS-CoV-2 was able to retain viability for 3-5 days in dried form or 7 days in solution at room temperature. SARS-CoV-2 could be detected under a wide range of pH conditions from pH 4 to pH 11 for several days, and for 1-2 days in stool at room temperature but lost 5 logs of infectivity. A variety of commonly used disinfectants and laboratory inactivation procedures were found to reduce viral viability effectively.

CONCLUSION

This study demonstrated the stability of SARS-CoV-2 on environmental surfaces, and raises the possibility of faecal-oral transmission. Commonly used fixatives, nucleic acid extraction methods and heat inactivation were found to reduce viral infectivity significantly, which could ensure hospital and laboratory safety during the SARS-CoV-2 pandemic.

Disinfectant potential in inactivation of epidemic keratoconjunctivitis-related adenoviruses by potassium peroxymonosulfate

PURPOSE

The aim of this study was to test the antiviral effectivity of potassium peroxymonosulfate (RUBYSTA^®, KYORIN) against five epidemic keratoconjunctivitis-related types of Human adenovirus D in vitro.

METHODS

Five types of Human adenovirus D (8, 37, 53, 54 and 56) were incubated with 1% potassium peroxymonosulfate, 0.1% sodium hypochlorite (NaClO) or alcohol-based disinfectant for 30 s or 1 min. These solutions were subjected to measurements of viral titres by infection assays in A549 cells. At day 6 post-infection, both, supernatants and cells, were collected and the viral genome was assessed by real-time polymerase chain reaction analysis.

RESULTS

Treatments with 1% potassium peroxymonosulfate led to significant reduction in all tested Human adenovirus D types comparable to disinfecting effects by 0.1% NaClO. Overall, potassium peroxymonosulfate demonstrated sufficient inactivation of the major epidemic keratoconjunctivitis-causing Human adenovirus D to be considered for disinfection and prevention purposes in ophthalmological clinics and hospitals.

CONCLUSION

This study demonstrated that potassium peroxymonosulfate is a promising disinfectant for the prevention of epidemic keratoconjunctivitis nosocomial infections in ophthalmological clinics.

Shelter housing for cats: Practical aspects of design and construction, and adaptation of existing accommodation

Practical relevance: Not every cat shelter will have purpose-built accommodation but housing designed with the basic needs of cats in mind, whether purpose-built or adapted from existing housing, will improve the experience of cats passing through the facility. Challenges: Designing and building accommodation for cats in shelters should be a thoughtful process. There is a range of different housing types available. A variety of factors, such as expected length of stay, type of cat, cost and disease risk, will influence which design is most appropriate.

AIMS

This review, the second in a two-part series, provides an overview of some of the essential requirements for housing shelter cats, either singly or in groups. Specific practical aspects of housing, including design, space allowances, cage furnishings and suitable construction materials, are discussed, and suggestions made for upgrading existing housing where extensive rebuilding is not feasible or realistic. Evidence base: There is a relatively small body of empirical evidence to inform shelter design recommendations. The recommendations in this article are based on a careful review of the available evidence, some of which has come from allied fields such as the care of experimental animals. Where evidence is not yet available, recommendations have been based on field experience and collective expert opinion.

Quaternary ammonium-based biomedical materials: State-of-the-art, toxicological aspects and antimicrobial resistance

Microbial infections affect humans worldwide. Many quaternary ammonium compounds have been synthesized that are not only antibacterial, but also possess antifungal, antiviral and anti-matrix metalloproteinase capabilities. Incorporation of quaternary ammonium moieties into polymers represents one of the most promising strategies for preparation of antimicrobial biomaterials. Various polymerization techniques have been employed to prepare antimicrobial surfaces with quaternary ammonium functionalities; in particular, syntheses involving controlled radical polymerization techniques enable precise control over macromolecular structure, order and functionality. Although recent publications report exciting advances in the biomedical field, some of these technological developments have also been accompanied by potential toxicological and antimicrobial resistance challenges. Recent evidenced-based data on the biomedical applications of antimicrobial quaternary ammonium-containing biomaterials that are based on randomized human clinical trials, the golden standard in contemporary medicinal science, are included in the present review. This should help increase visibility, stimulate debates and spur conversations within a wider scientific community on the implications and plausibility for future developments of quaternary ammonium-based antimicrobial biomaterials.

The wide spectrum high biocidal potency of Bioxy formulation when dissolved in water at different concentrations

Traditional surface disinfectants that have long been applied in medicine, animal husbandry, manufacturing and institutions are inconvenient at best and dangerous at worst. Moreover, some of these substances have adverse environmental impacts: for example, quaternary ammonium compounds ("quats") are reproductive toxicants in both fish and mammals. Halogens are corrosive both to metals and living tissues, are highly reactive, can be readily neutralized by metals, and react with organic matter to form toxic, persistent by-products such as dioxins and furans. Aldehydes may be carcinogenic to both human and animals upon repeated exposures, are corrosive, cross-link living tissues and many synthetic materials, and may lose efficacy when pathogens enzymatically adapt to them. Alcohols are flammable and volatile and can be enzymatically degraded by certain bacterial pathogens. Quats are highly irritating to mucous membranes and over time can induce pathogen resistance, especially if they are not alternated with functionally different disinfectants. In contrast, peracetic acid (PAA), a potent oxidizer, liberates hydrogen peroxide (itself a disinfectant), biodegrades to carbon dioxide, water and oxygen, and is at least as efficacious as contact biocides e.g., halogens and aldehydes. Nevertheless, the standard form of liquid PAA is highly corrosive, is neutralized by metals and organic matter, gives off noxious odours and must be stored in vented containers. For the reasons stated above, Bioxy formulations were developed, a series of powder forms of PAA, which are odourless, stable in storage and safe to transport and handle. They generate up to 10% PAA in situ when dissolved in water. A 0.2% aqueous solution of Bioxy (equivalent to 200 ppm PAA) effected a 6.76 log reduction in Methicillin-resistant Staphylococcus aureus (MRSA) within 2 minutes after application. A 5% aqueous solution of Bioxy achieved a 3.93 log reduction in the bovine tuberculosis bacillus Mycobacterium bovis, within 10 minutes after contact. A 1% solution of Bioxy reduced vancomycin-resistant enterococci (VRE) and Pseudomonas aeruginosa by 6.31 and 7.18 logs, respectively, within 3 minutes after application. A 0.5% solution of Bioxy inactivated porcine epidemic diarrhea virus (PEDV) within 15 minutes of contact, and a 5% solution of Bioxy realized a 5.36 log reduction in the spores of Clostridium difficile within 10 minutes of application. In summary, Bioxy is safe and easy to transport and store, poses negligible human, animal and environmental health risks, shows high levels of pathogen control efficacy and does not induce microbial resistance. Further investigations are recommended to explore its use as an industrial biocide.

Destruction of microcystins (cyanotoxins) by UV-254 nm-based direct photolysis and advanced oxidation processes (AOPs): influence of variable amino acids on the degradation kinetics and reaction mechanisms

Hepatotoxic microcystins (MCs) are the most frequently detected group of cyanobacterial toxins. This study investigated the degradation of common MC variants in water, MC-LR, MC-RR, MC-YR and MC-LA, by UV-254 nm-based processes, UV only, UV/H2O2, UV/S2O8(2-) and UV/HSO5(-). Limited direct photolysis of MCs was observed, while the addition of an oxidant significantly improved the degradation efficiency with an order of UV/S2O8(2-) > UV/HSO5(-) > UV/H2O2 at the same initial molar concentration of the oxidant. The removal of MC-LR by UV/H2O2 appeared to be faster than another cyanotoxin, cylindrospermopsin, at either the same initial molar concentration or the same initial organic carbon concentration of the toxin. It suggested a faster reaction of MC-LR with hydroxyl radical, which was further supported by the determined second-order rate constant of MCs with hydroxyl radical. Both isomerization and photohydration byproducts were observed in UV only process for all four MCs; while in UV/H2O2, hydroxylation and diene-Adda double bond cleavage byproducts were detected. The presence of a tyrosine in the structure of MC-YR significantly promoted the formation of monohydroxylation byproduct m/z 1061; while the presence of a second arginine in MC-RR led to the elimination of a guanidine group and the absence of double bond cleavage byproducts. It was therefore demonstrated in this study that the variable amino acids in the structure of MCs influenced not only the degradation kinetics but also the preferable reaction mechanisms.

Isolation and identification of feline herpesvirus type 1 from a South China tiger in China

In 2012, an FHV-1-like virus was isolated from a tiger that presented with clinical signs of sialorrhea, sneezing and purulent rhinorrhea. Isolation was performed with the FK81 cell line, and the virus was identified by PCR, transmission electron microscopy (TEM), and the phylogenetic analysis of the partial thymidine kinase (TK) and glycoprotein B (gB) genes. A total of 253 bp of the TK gene and 566 bp of the gB gene were amplified from the trachea of the tiger by PCR/RT-PCR method. Phylogenetic analysis showed that the isolate belonged to the same cluster with other FHV-1 strains obtained from GenBank. Herpes-like viruses with an envelope and diameters of approximately 200 nm were observed in the culture supernatants of FK81 cells inoculated with samples from the tiger. The FHV-1 infection was confirmed by an animal challenge experiment in a cat model. Our finding extends the host range of FHV-1 and has implications for FHV-1 infection and South China tiger conservation.

Inactivation of caliciviruses

The Caliciviridae family of viruses contains clinically important human and animal pathogens, as well as vesivirus 2117, a known contaminant of biopharmaceutical manufacturing processes employing Chinese hamster cells. An extensive literature exists for inactivation of various animal caliciviruses, especially feline calicivirus and murine norovirus. The caliciviruses are susceptible to wet heat inactivation at temperatures in excess of 60 °C with contact times of 30 min or greater, to UV-C inactivation at fluence ≥30 mJ/cm2, to high pressure processing >200 MPa for >5 min at 4 °C, and to certain photodynamic inactivation approaches. The enteric caliciviruses (e.g.; noroviruses) display resistance to inactivation by low pH, while the non-enteric species (e.g.; feline calicivirus) are much more susceptible. The caliciviruses are inactivated by a variety of chemicals, including alcohols, oxidizing agents, aldehydes, and β-propiolactone. As with inactivation of viruses in general, inactivation of caliciviruses by the various approaches may be matrix-, temperature-, and/or contact time-dependent. The susceptibilities of the caliciviruses to the various physical and chemical inactivation approaches are generally similar to those displayed by other small, non-enveloped viruses, with the exception that the parvoviruses and circoviruses may require higher temperatures for inactivation, while these families appear to be more susceptible to UV-C inactivation than are the caliciviruses.

Feline respiratory disease complex

Feline respiratory disease complex (FRDC) refers to the characteristic acute presentation of a contagious respiratory or ocular disease caused by one or multiple pathogens. Environmental and host factors impact the transmission, clinical presentation, preventive strategy, and treatment of affected cats. The FRDC is especially problematic in settings where large numbers of cats cohabit, including animal shelters, catteries, and semi-feral colonies. Although elimination of FRDC is an unrealistic goal, improved understanding can lead to strategies to minimize disease impact.

Occurrence of bacteria and viruses on elementary classroom surfaces and the potential role of classroom hygiene in the spread of infectious diseases

The presence of microorganisms on common classroom contact surfaces (fomites) was determined to identify the areas most likely to become contaminated. Six elementary classrooms were divided into control and intervention groups (cleaned daily with a quaternary ammonium wipe) and tested for heterotrophic bacteria. Three classrooms were also tested for norovirus and influenza A virus. Frequently used fomites were the most contaminated; water fountain toggles, pencil sharpeners, keyboards, and faucet handles were the most bacterially contaminated; desktops, faucet handles, and paper towel dispensers were the most contaminated with viruses. Influenza A virus was detected on up to 50% and norovirus on up to 22% of surfaces throughout the day. Children in the control classrooms were 2.32 times more likely to report absenteeism due to illness than children in the intervention classrooms and were absent longer (on average). Improved classroom hygiene may reduce the incidence of infection and thus student absenteeism.

A nosocomial outbreak of feline calicivirus associated virulent systemic disease in France

This report describes a nosocomial outbreak of feline calicivirus (FCV) associated virulent systemic disease (VSD) in a French veterinary teaching hospital in 2005. The outbreak started in March and resolved within 1 month. Signs, clinical course, clinicopathological findings and lesions were typical of FCV-induced VSD. FCV infection was confirmed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Among the eight infected cats, two had to be euthanased, three died, and three recovered after medical treatment. Virus could not be confined inside the animal hospital and on two occasions, students' own cats became infected. Subsequent genetic sequencing studies confirmed that the eight cats were infected with the same strain of virus, and that it was distinct from those involved in the US and UK outbreaks of VSD. Virulence and viral excretion patterns of the isolated strain were further characterised by experimental infection.

Use of murine norovirus as a surrogate to evaluate resistance of human norovirus to disinfectants

Murine norovirus (MNV) was used as a surrogate to study resistance of human norovirus to disinfectants used in hospitals. MNV was sensitive to alcohol, alcohol hand rubs, bleach, and povidone iodine-based disinfectant. Real-time reverse transcription-PCR results indicated that the presence of viral RNA did not correlate with the presence of infectious virus.

Protective effect of low-concentration chlorine dioxide gas against influenza A virus infection

Influenza virus infection is one of the major causes of human morbidity and mortality. Between humans, this virus spreads mostly via aerosols excreted from the respiratory system. Current means of prevention of influenza virus infection are not entirely satisfactory because of their limited efficacy. Safe and effective preventive measures against pandemic influenza are greatly needed. We demonstrate that infection of mice induced by aerosols of influenza A virus was prevented by chlorine dioxide (ClO2) gas at an extremely low concentration (below the long-term permissible exposure level to humans, namely 0.1 p.p.m.). Mice in semi-closed cages were exposed to aerosols of influenza A virus (1 LD50) and ClO2 gas (0.03 p.p.m.) simultaneously for 15 min. Three days after exposure, pulmonary virus titre (TCID50) was 102.6±1.5 in five mice treated with ClO2, whilst it was 106.7±0.2 in five mice that had not been treated (P=0.003). Cumulative mortality after 16 days was 0/10 mice treated with ClO2 and 7/10 mice that had not been treated (P=0.002). In in vitro experiments, ClO2 denatured viral envelope proteins (haemagglutinin and neuraminidase) that are indispensable for infectivity of the virus, and abolished infectivity. Taken together, we conclude that ClO2 gas is effective at preventing aerosol-induced influenza virus infection in mice by denaturing viral envelope proteins at a concentration well below the permissible exposure level to humans. ClO2 gas could therefore be useful as a preventive means against influenza in places of human activity without necessitating evacuation.

Feline calicivirus

Feline calicivirus (FCV) is an important and highly prevalent pathogen of cats. It belongs to the family Caliciviridae which includes other significant pathogens of man and animals. As an RNA virus, high polymerase error rates convey upon FCV a high genome plasticity, and allow the virus to respond rapidly to environmental selection pressures. This makes the virus very adaptable and has important implications for clinical disease and its control. Being genetically diverse, FCV is associated with a range of clinical syndromes from inapparent infections to relatively mild oral and upper respiratory tract disease with or without acute lameness. More recently, highly virulent forms of the virus have emerged associated with a systemic infection that is frequently fatal. A proportion of FCV infected cats that recover from acute disease, remain persistently infected. In such cats, virus evolution is believed to help the virus to evade the host immune response. Such long-term carriers may only represent a minority of the feline population but are likely to be crucial to the epidemiology of the virus. Vaccination against FCV has been available for many years and has effectively reduced the incidence of clinical disease. However, the vaccines do not prevent infection and vaccinated cats can still become persistently infected. In addition, FCV strain variability means that not all strains are protected against equally. Much progress has been made in understanding the biology and pathogenesis of this important feline virus. Challenges for the future will necessarily focus on how to control the variability of this virus particularly in relation to emerging virulent strains and vaccination.

Feline herpesvirus

Feline herpesvirus (FHV-1; felid herpesvirus 1 (FeHV-1)) is an alphaherpesvirus of cats closely related to canine herpesvirus-1 and phocine herpesvirus-1. There is only one serotype of the virus and it is relatively homogenous genetically. FeHV-1 is an important cause of acute upper respiratory tract and ocular disease in cats. In addition, its role in more chronic ocular disease and skin lesions is increasingly being recognised. Epidemiologically, FeHV-1 behaves as a typical alphaherpesvirus whereby clinically recovered cats become latently infected carriers which undergo periodic episodes of virus reactivation, particularly after a stress. The primary site of latency is the trigeminal ganglion. Conventional inactivated and modified-live vaccines are available and protect reasonably well against disease but not infection, although viral shedding may be reduced. Genetically engineered vaccines have also been developed, both for FeHV-1 and as vector vaccines for other pathogens, but none is as yet marketed.

Evaluation of the efficacy of disinfectants against Puumala hantavirus by real-time RT-PCR

Puumala virus, a hantavirus belonging to the Bunyaviridae family, causes a human disease known as nephropathia epidemica, a mild form of hemorrhagic fever with renal syndrome. The implementation of effective decontamination procedures is critical in hantavirus research to minimize the risk of personnel exposure. This study investigated the efficacy of Clidox^®, Dettol^®, ethanol, Halamid-d^®, peracetic acid, sodium hypochloride and Virkon^®S for inactivating Puumala virus. A real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to quantify Puumala virus before and after treatment with these products. Inactivation of Puumala virus was effective after 10 min with all products except ethanol. Inactivation with absolute ethanol was effective only after 30 min. Using the qRT-PCR method, this study has shown that the commercially available products Clidox^®, Halamid-d^® and Virkon^®S in particular represent a rapid and safe way to decontaminate surfaces with possible Puumala virus contamination. These products can be used in solutions of 1–2%, with contact times greater than 10 min, for inactivating effectively Puumala virus.

Efficacy of three ethanol-based hand rubs against feline calicivirus, a surrogate virus for norovirus

We investigated the efficacy of three ethanol-based hand rubs (Sterillium Virugard, 95% ethanol; Sterillium Rub, 80% ethanol; Desderman N, 75.1% ethanol) against feline calicivirus (FCV), the surrogate virus for norovirus, on artificially contaminated hands of healthy volunteers. The ASTM E 1838-02 standard was used. Experiments were controlled with 70% ethanol and 70% propan-1-ol which were previously found to have maximal efficacy against FCV. In the first step, three different organic loads (5% fetal bovine serum, 5% faecal suspension and the tripartite ASTM load) were compared. A significant influence of the type of organic load was found (P<0.001, ANOVA). In the second step, the hand rubs were investigated with a 5% faecal suspension as a challenging organic load. The hand rub based on 95% ethanol was more effective than those based on 70% ethanol (mean log10 reduction factor: 2.17 vs. 1.56; P=0.17) and 70% propan-1-ol (mean RF: 1.63 vs. 0.95; P=0.0003). The hand rub based on 80% ethanol was also more effective than those based on 70% ethanol (mean RF: 1.25 vs. 1.03: P=0.20) and 70% propan-1-ol (mean RF: 1.43 vs. 1.09; P=0.03). The hand rub based on 75.1% ethanol was less effective than those based on 70% ethanol (mean RF: 1.07 vs. 1.27; P=0.47) and 70% propan-1-ol (mean RF: 0.78 vs. 0.97; P=0.35). Based on our data, ethanol has superior efficacy against FCV than propan-1-ol. In addition, a higher ethanol concentration in three commercially available hand rubs was associated with better efficacy against FCV.

Feline infectious disease control in shelters

No single factor determines whether a population remains healthy or disease rages out of control. All host and environmental factors taken together provide a number of tools to protect the vulnerable feline shelter population,however. A well-conceived infectious disease control program contributes to improved public perception, increased adoptions, and a healthier feline population within the shelter and in the community in general.

Human norovirus infection and the lessons from animal caliciviruses

PURPOSE OF REVIEW

Human noroviruses are a major cause of infectious intestinal disease, particularly in the health sector, with considerable knock-on effects on care provision through ward closures and staff sickness. This review will describe recent advances in our understanding of human noroviruses. In addition, we will consider related nonhuman caliciviruses to highlight some potential difficulties in the control of caliciviral disease.

RECENT FINDINGS

Using more sensitive reverse transcriptase polymerase chain reaction based assays, noroviruses are now recognized as the most common cause of infectious intestinal disease in the community, as well as outbreaks of the infectious intestinal disease. After recovery from acute disease, some individuals continue shedding norovirus, particularly if immunosuppressed. The noroviruses are extremely variable, which has important implications for protection following challenge, and for future vaccination. From amongst this variability, new strains have emerged with the potential to spread widely. Recently a mouse norovirus has been identified which will afford new insights into the biology of these important viruses. Studies on human susceptibility have identified some resistant individuals in the population and a potential virus receptor, which may lead to the development of novel antiviral therapies.

SUMMARY

Lack of cell culture systems for the human noroviruses is being overcome by molecular technologies. Such studies have provided new insight into the significance and epidemiology of these viruses and opened the possibility of disease control through vaccination. Work on nonhuman caliciviruses has interesting parallels with human noroviruses, and provides new insights into the understanding of these important human pathogens.

An epizootic of highly virulent feline calicivirus disease in a hospital setting in New England

This article reports an outbreak of 24 cases of an unusually virulent feline calicivirus (FCV) infection in a small animal hospital. The circumstances and disease signs were very similar to those recently described in an outbreak of FCV hemorrhagic disease in Northern California (Vet. Microbiol. 73 (2000) 281). The virus entered the facility through shelter cats showing upper respiratory signs. Affected cats manifested high fever, anorexia, labored respirations, oral ulceration, facial and limb edema, icterus, and pancreatitis. The infection spread rapidly among the patients by contaminated animal caretakers and hospital equipment. One case of fomite transmission from an employee to a housecat was documented. Prior vaccination, even with multiple doses of FCV-F9-based live calicivirus vaccine, was not protective. Affected cats often required extensive supportive care for 7-10 days, and the overall mortality from death and euthanasia was 32%. The strain of FCV responsible for this outbreak was genetically and serologically distinct from the FCV strain responsible for a similar epizootic and the FCV-F9 strain contained in most vaccines. Outbreaks of this type are being reported with increasing frequency, and are often associated with the practice of treating sick shelter cats in private practices. Similar to the present epizootic, outbreaks of FCV hemorrhagic disease have been self-limiting, but require prompt application of strict quarantine, isolation, personnel sanitation, and disinfection procedures.

Update on feline calicivirus: new trends

In addition to being important upper respiratory tract pathogens of cats, FCVs are increasingly reported as a cause of a highly contagious febrile hemorrhagic syndrome. Strains causing this syndrome are genetically different from the vaccine strain and other nonhemorrhagic FCV isolates. They apparently differ from one outbreak to another. The syndrome is characterized variably by fever; cutaneous edema and ulcerative dermatitis; upper respiratory tract signs; anorexia; occasionally icterus, vomiting, and diarrhea; and a mortality that approaches 50%. Adult cats tend to be more severely affected than kittens, and vaccination does not appear to have a significant protective effect. Rapid recognition of the disease through identification of clinical signs and appropriate testing, followed by strict institution of disinfection, isolation, and quarantine measures, are essential to prevent widespread mortality resulting from the infection.