Group activity of mice in communal home cage used as an indicator of disease progression and rate of recovery: Effects of LPS and influenza virus.

Large numbers of rodents are often used in the study of disease progression and in the evaluation of its potential treatments. To avoid subjective observation and to minimize home cage interference, we developed a computerized home cage monitoring system (HCMS100) based on a standard cage rack adapted with a single laser beam and a detector mounted on each cage, enabling to monitor mice movements based on laser beam interruptions. This retrofit system provided continuous and uninterrupted monitoring of spontaneous movement of a group of mice in a home cage. Validity was evaluated using disease state induced by LPS modelling bacterial infection and by influenza virus. RESULTS: Spontaneous activity of different number of mice (2-8) per cage showed the expected circadian rhythm with increased activity during the night, and its extent dependent on the number of mice in the cage. Females and males show similar circadian rhythm. Intranasal LPS administration and pulmonary infection with live influenza virus resulted in major reduction of mice activity along disease progression. Increase in activity over time was a good indicator of the recovery process from both LPS exposure and the flu infection. CONCLUSIONS: HCMS100 was shown to be a reliable, inexpensive, easy to use system that requires no changes in the common housing of various experimental animals (mice, hamsters, rats etc.). With minimal intervention, HCMS100 provides a continuous record of group activity with clear pattern of circadian rhythm, allowing long term recording of home cage activity even in restricted access environments.

Equine influenza vaccination as reported by horse owners and factors influencing their decision to vaccinate or not.

BACKGROUND: Equine influenza virus is a highly contagious respiratory pathogen that causes pyrexia, anorexia, lethargy and coughing in immunologically naïve horses. Vaccines against equine influenza are available and vaccination is mandatory for horses that participate in affiliated competitions, but this group forms a small proportion of the total horse population. The aims of this study were to: i) identify the equine influenza vaccination rate as reported in 2016 by horse owners in the United Kingdom (UK); ii) examine the demographics of owners and horses which were associated with significantly lower influenza vaccination rates and iii) explore factors that influence horse owners' decisions around influenza vaccine uptake. RESULTS: Responses from 4837 UK horse owners who were responsible for 10,501 horses were analysed. An overall equine influenza vaccination rate of 80% (8385/10501) was reported. Several owner demographic characteristics were associated with significantly lower (p<0.05) reported equine influenza vaccination rates including: some geographical locations, increasing horse owner age, annual household income of less that £15,000 and owning more than one horse. Horse-related features which were associated with significantly lower reported equine influenza vaccination rates included age ranges of <4 years and > 20 years, use as a companion or breeding animal or leaving their home premises either never or at most once a year. The most common reasons cited for failing to vaccinate horses was no competition activity, lack of exposure to influenza and expense of vaccines. In contrast, the most common underlying reasons given by horse owners who vaccinated their horse were protection of the individual horse against disease, veterinary advice and to protect the national herd. Owners of vaccinated horses had less previous experience of an influenza outbreak or adverse reaction to vaccination compared with owners of unvaccinated horses. CONCLUSIONS: This study documented a high rate of equine influenza vaccination as reported by owners in a substantial number of horses in the UK, but this does not reflect the level of protection. Sub-populations of horses which were less likely to be vaccinated and the factors that influence each owner's decision around vaccination of their horses against equine influenza were identified, but may alter following the 2019 European influenza outbreak. This information may nevertheless help veterinary surgeons identify "at-risk" patients and communicate more personalised advice to their horse-owning clients. It may also influence educational campaigns about equine influenza directed to horse owners, which aim to improve uptake of vaccination against this pathogen.

Limited awareness of animal influenza prevention and control among Dai Lue smallholder farmers in Southwest China.

Awareness of animal influenza and its prevention and control is important for ensuring livestock health, production and welfare. In China, a country stereotyped as a major source of emerging zoonotic infectious diseases, research on the public understanding of animal influenza is limited to the Han, the main ethnic group. The present qualitative study in Southwest China investigated awareness of animal influenza among the Dai, an ethnic minority. The participants (15 men and 10 women, ages 18-83) were smallholder farmers of pigs and poultry in rural areas of Jinghong, Xishuangbanna, Yunnan Province. A mixture of interviews and group discussions took place in homes and villages. The participants were asked about their knowledge of avian influenza (H7N9), swine influenza (H1N1), precautions taken to protect against influenza, procedures when animals were sick and perceived risk of animal influenza. The data were analysed following coding and thematic analysis. The findings demonstrated a limited understanding of animal health and welfare among participants. Specifically, they were largely unaware of animal influenza (H7N9, H1N1) including its causes, symptoms, prevention and treatment. The farmers were also uninformed of the risks they faced and unknowingly engaged in behaviours which increased direct or indirect exposure to infected animals, a risk factor for human infection. They also reported poor usage of veterinary services. In order to guarantee the health, welfare and production of their livestock, immediate action is needed to enable Dai smallholder farmers to prevent and respond to animal influenza effectively and timely.

Environmental enrichment attenuates hippocampal neuroinflammation and improves cognitive function during influenza infection.

Recent findings from our lab have shown that peripheral infection of adult mice with influenza A/PR/8/34 (H1N1) virus induces a neuroinflammatory response that is paralleled by loss of neurotrophic and glial regulatory factors in the hippocampus, and deficits in cognitive function. Environmental enrichment has been shown to exert beneficial effects on the brain and behavior in many central nervous system (CNS) disorders, but its therapeutic potential during peripheral viral infection remains unknown. Therefore, the objective of the present study was to determine if long-term continuous exposure to environmental enrichment could prevent and/or attenuate the negative effects of influenza infection on the hippocampus and spatial cognition. Mice were housed in enriched or standard conditions for 4 months, and continued to live in their respective environments throughout influenza infection. Cognitive function was assessed in a reversal learning version of the Morris water maze, and changes in hippocampal expression of proinflammatory cytokines (IL-1ß, IL-6, TNF-α, IFN-α), neurotrophic (BDNF, NGF), and immunomodulatory (CD200, CX3CL1) factors were determined. We found that environmental enrichment reduced neuroinflammation and helped prevent the influenza-induced reduction in hippocampal CD200. These changes were paralleled by improved cognitive performance of enriched mice infected with influenza when compared to infected mice in standard housing conditions. Collectively, these data are the first to demonstrate the positive impact of environmental enrichment on the brain and cognition during peripheral viral infection, and suggest that enhanced modulation of the neuroimmune response may underlie these beneficial effects.

Pig producers' perceptions of the Influenza Pandemic H1N1/09 outbreak and its effect on their biosecurity practices in Australia.

The Influenza Pandemic (H1N1/09) virus was first reported in humans in Mexico in April 2009 and a pandemic level was declared on 11th of June 2009 by the World Health Organization (Chan, 2009; WHO, 2009a). Public misconceptions about the transmission of H1N1/09 were caused by the inadequate naming of the disease as 'swine influenza'. This cross-sectional study was conducted at the height of the outbreak in the Australian human population and before the virus was reported in the first piggery in Australia in July 2009 (OIE, 2009b; Holyoake et al., 2011). The aims of this study were to evaluate pig producers' perceptions about the virus and the outbreak financial impact and influence on on-farm biosecurity practices. A questionnaire was designed and posted to Australian Pork Limited (APL) members (n=460), obtaining responses from 182 producers (39.6%). Pig producers had good general knowledge on potential transmission pathways for H1N1/09 between people, with direct or close contact with a sick person perceived as the most likely pathways. Changes on biosecurity practices, such as asking visitors if they had recently been overseas (27.8%) and not allowing any visitor to inspect their pigs (18.3%), were reported among respondents. In addition, approximately 40% of producers asked their employees to notify flu like symptoms, consulted a veterinarian on H1N1/09 and visited websites to seek information on H1N1/09. A higher adoption of these practices was observed among large (>100 sows) than small herds. Only 2.9% of respondents reported a reduction in pig sales during the outbreak. However, approximately one third of producers reported being financially and emotionally stressed, 38.2% were distressed about the health of their pigs and 16.7% about their own health. The most important sources of information were APL (93%), veterinarians (89%) and the state Department of Primary Industries (DPI) (75%). The first two considered the most trusted sources of information. Television, radio and other farmers were considered more important sources of information by small herds and veterinarians by larger herds. Producers believed that the H1N1/09 outbreak was better managed by the pork industry (89.9%) than by the health authorities (58.8%), and the on-going communication with APL was the main strength of the outbreak management. Communication and extension programs in future outbreaks should consider the needs of all sectors of the pig industry to increase their effectiveness.

Overview of the industry and social impacts of the 2007 Australian equine influenza outbreak.

The equine influenza (EI) outbreak occurred at the worst time of the year as far as the horse industry was concerned. All horse sports and horse breeds had events planned in the spring, including those relating to qualification for the 2008 Beijing Olympic Games. These were all disrupted and many were cancelled. The social and industry impacts were extensive, and included difficulties related to communication, animal welfare, vaccination, movement restrictions, economics, as well as the psychological stresses experienced by those involved, especially those for whom their primary source of income was horse related.

Factors associated with high psychological distress in horse industry participants during the 2007 Australian equine influenza outbreak and evidence of recovery after 1 year.

This short report summarises data on the prevalence of high psychological distress in horse industry participants during the 2007 Australian equine influenza (EI) outbreak and the statistical analysis undertaken to identify the factors associated with this high psychological distress. In addition, follow-up data collected 1 year later are reported briefly.

An insider's view of the lockdown at Moonbi during the Australian equine influenza outbreak.

Participants in the 1- and 2-day Tamworth Dressage Club (TDC) annual dressage championships arrived in Moonbi, New South Wales (NSW) as reports of the equine influenza outbreak surfaced on 25 August 2007. Three horses who had attended a competition in Maitland the weekend before had been showing flu-like symptoms and the next day the site was declared a suspect premise. On 27 August, infection was confirmed and the site was placed in total quarantine. Although most participants had travelled long distances to compete and did not have provisions for them or their horses, the quarantine was not lifted until 3 October, having a great social and personal impact on all those trapped in Moonbi.

Influenza virus-specific immunological memory is enhanced by repeated social defeat.

Immunological memory (MEM) development is affected by stress-induced neuroendocrine mediators. Current knowledge about how a behavioral interaction, such as social defeat, alters the development of adaptive immunity, and MEM is incomplete. In this study, the experience of social disruption stress (SDR) prior to a primary influenza viral infection enhanced the frequency and function of the T cell memory pool. Socially stressed mice had a significantly enlarged population of CD8(+) T cells specific for the immunodominant NP366-74 epitope of A/PR/8/34 virus in lung and spleen tissues at 6-12 wk after primary infection (resting memory). Moreover, during resting memory, SDR-MEM mice responded with an enhanced footpad delayed-type hypersensitivity response, and more IFN-gamma-producing CD4(+) T cells were detected after ex vivo stimulation. When mice were rechallenged with A/PR/8/34 virus, SDR-MEM mice terminated viral gene expression significantly earlier than MEM mice and generated a greater D(b)NP(366-74)CD8(+) T cell response in the lung parenchyma and airways. This enhancement was specific to the T cell response. SDR-MEM mice had significantly attenuated anti-influenza IgG titers during resting memory. Similar experiments in which mice were primed with X-31 influenza and challenged with A/PR/8/34 virus elicited similar enhancements in the splenic and lung airway D(b)NP(366-74)CD8(+) T cell populations in SDR-MEM mice. This study demonstrates that the experience of repeated social defeat prior to a primary viral infection significantly enhances virus-specific memory via augmentation of memory T cell populations and suggests that social stressors should be carefully considered in the design and analysis of future studies on antiviral immunity.

Attenuation of the influenza virus sickness behavior in mice deficient in Toll-like receptor 3.

Certain sickness behaviors occur consistently in influenza-infected humans and mice. These include body temperature changes, somnolence, and anorexia. Several cytokines serve as mediators of the influenza acute phase response (APR), including these sickness behaviors, and one likely inducer of these cytokines is dsRNA produced during viral replication. TLR3 is known to be one of the host cellular components capable of recognizing dsRNA and activating cytokine synthesis. To determine the role of TLR3-detected viral dsRNA in the causation of viral symptoms, TLR3-deficient mice (TLR3 knockouts, or KOs) were infected with a marginally-lethal dose of mouse-adapted X-31 influenza virus. TLR3 KOs and their wild-type (WT) controls were monitored for baseline body temperature, locomotor activity, and sleep profiles prior to infection. Both mouse strains were then infected and monitored for changes in these sickness behaviors plus body weight changes and mortality for up to 14days post-infection. Consistent with the observations that influenza pathology is reduced in TLR3 KOs, we showed that hypothermia after post-infection day 5 and the total loss of body weight were attenuated in the TLR3 KOs. Sleep changes characteristic of this infection model [particularly increased non-rapid-eye-movement sleep (NREMS)] were also attenuated in TLR3 KOs and returned to baseline values more rapidly. Locomotor activity suppression was similar in both strains. Therefore virus-associated dsRNA detected by TLR3 appears to play a substantial role in mediating several aspects of the influenza syndrome in mice.

The olfactory nerve has a role in the body temperature and brain cytokine responses to influenza virus.

Mouse-adapted human influenza virus is detectable in the olfactory bulbs of mice within hours after intranasal challenge and is associated with enhanced local cytokine mRNA and protein levels. To determine whether signals from the olfactory nerve influence the unfolding of the acute phase response (APR), we surgically transected the olfactory nerve in mice prior to influenza infection. We then compared the responses of olfactory-nerve-transected (ONT) mice to those recorded in sham-operated control mice using measurements of body temperature, food intake, body weight, locomotor activity and immunohistochemistry for cytokines and the viral antigen, H1N1. ONT did not change baseline body temperature (Tb); however, the onset of virus-induced hypothermia was delayed for about 13 h in the ONT mice. Locomotor activity, food intake and body weights of the two groups were similar. At 15 h post-challenge fewer viral antigen-immunoreactive (IR) cells were observed in the olfactory bulb (OB) of ONT mice compared to sham controls. The number of tumor necrosis factor alpha (TNFalpha)- and interleukin 1beta (IL1beta)-IR cells in ONT mice was also reduced in the OB and other interconnected regions in the brain compared to sham controls. These results suggest that the olfactory nerve pathway is important for the initial pathogenesis of the influenza-induced APR.

Neonatal infection with neurotropic influenza A virus affects working memory and expression of type III Nrg1 in adult mice.

Epidemiological studies suggest that early life infections may contribute to the development of psychiatric disorders characterized by cognitive deficits. Here, we studied the effects of a neonatal influenza A/WSN/33 virus infection on locomotor activity, working memory and emotional behavior in adult mice. In addition to wild type mice, immunodeficient (Tap1(-/-)) mice lacking functional CD8(+) T cells, were included in the study to model the potential influence of a genetic deficit relating to virus clearance. Three to four months after the infection, infected Tap1(-/-) mice, but not wild type mice, exhibited deficits in working memory as well as increased rearing activity and anxiety. In the medial prefrontal cortices of these infected Tap1(-/-) mice reduced levels of type III Nrg1 transcripts were observed supporting a role for neuregulin 1 signaling in neuronal circuits involved in working memory. Virus replication, distribution or clearance did not differ between the two genotypes. The lack of CD8(+) T cells, however, appeared to contribute to a more pronounced glia response in Tap1(-/-) than in wild type mice. Thus, the present study suggest that the risk of developing deficits in cognitive and emotional behavior following a CNS infection during brain development is influenced by genetic variation in genes involved in the immune response.

Factors influencing psychological distress during a disease epidemic: data from Australia's first outbreak of equine influenza.

BACKGROUND: In 2007 Australia experienced its first outbreak of highly infectious equine influenza. Government disease control measures were put in place to control, contain, and eradicate the disease; these measures included movement restrictions and quarantining of properties. This study was conducted to assess the psycho-social impacts of this disease, and this paper reports the prevalence of, and factors influencing, psychological distress during this outbreak. METHODS: Data were collected using an online survey, with a link directed to the affected population via a number of industry groups. Psychological distress, as determined by the Kessler 10 Psychological Distress Scale, was the main outcome measure. RESULTS: In total, 2760 people participated in this study. Extremely high levels of non-specific psychological distress were reported by respondents in this study, with 34% reporting high psychological distress (K10 > 22), compared to levels of around 12% in the Australian general population. Analysis, using backward stepwise binary logistic regression analysis, revealed that those living in high risk infection (red) zones (OR = 2.00; 95% CI: 1.57-2.55; p < 0.001) and disease buffer (amber) zones (OR = 1.83; 95% CI: 1.36-2.46; p < 0.001) were at much greater risk of high psychological distress than those living in uninfected (white zones). Although prevalence of high psychological distress was greater in infected EI zones and States, elevated levels of psychological distress were experienced in horse-owners nationally. Statistical analysis indicated that certain groups were more vulnerable to high psychological distress; specifically younger people, and those with lower levels of formal educational qualifications. Respondents whose principal source of income was from horse-related industry were more than twice as likely to have high psychological distress than those whose primary source of income was not linked to horse-related industry (OR = 2.23; 95% CI: 1.82-2.73; p < 0.001). CONCLUSION: Although, methodologically, this study had good internal validity, it has limited generalisability because it was not possible to identify, bound, or sample the target population accurately. However, this study is the first to collect psychological distress data from an affected population during such a disease outbreak and has potential to inform those involved in assessing the potential psychological impacts of human infectious diseases, such as pandemic influenza.

Moderate exercise protects mice from death due to influenza virus.

We wanted to determine if different doses of exercise, performed in the initial days after infection when the host is mounting an immune response, altered mortality, and morbidity to influenza virus infection in mice. Forty hemagglutinating units of influenza virus (A/Puerto Rico/8/34) were administered intranasally to lightly anesthetized mice. Male Balb/cByJ mice were randomized to one of three groups: sedentary control (CON); moderate (MOD) exercise (20-30 min at 8-12 m/min); or prolonged (PRO) exercise (2.5 h at 8-12 m/min). Mice exercised on a treadmill 4 h post-infection and for three more consecutive days before symptom onset. Mortality, morbidity, bodyweight, and food intake were assessed. MOD had a significantly (p = .007) higher survival (18 of 22; 82%) rate when compared to CON (10 of 23; 43%). There was no difference in morbidity between MOD and CON, despite improved survival. PRO exhibited a survival rate of 30% (p = .29 vs. CON) and demonstrated significantly higher morbidity on several days. While all groups exhibited anorexia and significant body weight loss (approximately 30-35%) post-infection, exercise had little effect on these variables. We demonstrate that moderate exercise, performed in the initial days after influenza infection, significantly decreased mortality in mice. Prolonged exercise led to increased morbidity and tended to decrease survival.

Maternal influenza infection causes marked behavioral and pharmacological changes in the offspring.

Maternal viral infection is known to increase the risk for schizophrenia and autism in the offspring. Using this observation in an animal model, we find that respiratory infection of pregnant mice (both BALB/c and C57BL/6 strains) with the human influenza virus yields offspring that display highly abnormal behavioral responses as adults. As in schizophrenia and autism, these offspring display deficits in prepulse inhibition (PPI) in the acoustic startle response. Compared with control mice, the infected mice also display striking responses to the acute administration of antipsychotic (clozapine and chlorpromazine) and psychomimetic (ketamine) drugs. Moreover, these mice are deficient in exploratory behavior in both open-field and novel-object tests, and they are deficient in social interaction. At least some of these behavioral changes likely are attributable to the maternal immune response itself. That is, maternal injection of the synthetic double-stranded RNA polyinosinic-polycytidylic acid causes a PPI deficit in the offspring in the absence of virus. Therefore, maternal viral infection has a profound effect on the behavior of adult offspring, probably via an effect of the maternal immune response on the fetus.

The role of cytokines in infection-related behavior.

Infections are associated with a specific behavioral pattern that includes hypomotility, hypophagia, increased sleep, decreased libido, and decreased exploration. This behavioral response is considered adaptive and important for the survival of the animal. A similar behavioral pattern was observed following treatment with endotoxin (lipopolysaccharide [LPS]) and cytokines, such as interleukin-1 (IL-1). Because the secretion of these cytokines is induced by LPS and infections, it is possible that they mediate the behavioral responses to infection. We have studied ingestive behavior and locomotor activity in mice following infection with influenza virus, or injection of LPS, IL-1, or IL-6. A lethal dose of influenza virus, LPS, IL-1a and IL-1b each decreased the intake of sweetened condensed milk and 24-hour food pellet intake and decreased locomotor activity. Mouse IL-6 was ineffective. A sublethal dose of influenza virus decreased food pellet intake and locomotor activity, but did not significantly alter milk intake. Indomethacin prevented the behavioral responses to IL-1, and attenuated those to LPS, but had only a very small effect on those to influenza virus. Similar results were obtained with the IL-1-receptor antagonist (IL-1ra); it completely prevented the responses to IL-1, attenuated those to LPS, but, even after chronic high dose administration, attenuated the effects of influenza virus infection only slightly. Our results suggest that while IL-1 may play an important role in the responses to infection, IL-6 does not. Moreover, IL-1 cannot be the only factor contributing to the altered behavior of LPS-injected or influenza virus-infected mice.

Sickness behavior in mice deficient in interleukin-6 during turpentine abscess and influenza pneumonitis.

Interleukin-6 (IL-6), among other cytokines, is thought to be involved in the regulation of sickness behavior (e.g., anorexia, cachexia, fever, and lethargy) induced by infections bacterial and viral origin) and sterile tissue necrosis (burns and surgical traumas). Mice deficient in IL-6 (IL-6 KO) were generated by gene targeting. Homozygous IL-6 KO male and female mice and their appropriate controls were implanted with biotelemeters to monitor body temperature (Tb) and motor activity (Act). Normal circadian rhythms in Tb and Act as well as rates of food intake and weight gain did not differ significantly between sex-matched IL-6 KO and control groups at 30 degrees C in a 12:12-h light-dark cycle. Sterile tissue damage was induced in mice by subcutaneous injection of turpentine (0.1 ml, left hindlimb). Influenza pneumonitis was induced by intranasal inoculation of mouse-adapted influenza A virus (17.5 plaque-forming units). Lack of IL-6 completely prevented fever, anorexia, and cachexia because of turpentine abscess in both sexes. It did not prevent lethargy, although IL-6 KO mice recovered to normal Act significantly sooner than wild-type mice. Symptoms of sickness were only slightly modified during influenza virus infection in IL-6 KO mice. Attenuation of sickness behavior was more pronounced in IL-6 KO female than in male mice. We conclude that, although IL-6 is induced during both turpentine abscess and influenza infection, this cytokine appears to be more critical in induction of the symptoms of sickness behavior during sterile tissue abscess than during influenza infection.

Body temperature and nesting behavior following influenza challenge in mice: effects of age.

We studied the interaction of age and influenza on core body temperature (Tc) of mice. Following influenza challenge, 2-mo-old female BALB/c mice demonstrated a significant fall in Tc. Female BALB/c mice 24 mo of age had lower baseline Tc than young mice and a larger fall in Tc post influenza challenge. We noted there were marked differences in nesting behavior between the young and aged mice. A nesting score was devised, and we found that at baseline, aged mice had a much lower score than young mice (15.6 +/- 7.4 vs. 24.7 +/- 0.3, P < 0.0001). Following influenza challenge, nesting behavior of young mice dropped considerably, while no significant change occurred in the behavior of aged mice. When mice were housed without bedding, there were significant decreases in Tc of young, but not aged mice. There was a further fall in Tc with influenza challenge in young mice. These data imply that nesting is an important mechanism for maintaining Tc in young mice, but alternative mechanisms are used by aged mice. The lower body temperatures in the aged mice are similar to studies in aging humans.

Effects of alprazolam on influenza virus infection in stressed mice.

The review of the literature shows that stress can adversely affect influenza A virus infection. In this report, we study the effects of chronic alprazolam (1 mg/kg/day), a central benzodiazepine agonist anxiolytic, on the influenza A (PR-8/34) virus specific immune injury in mice exposed to a chronic auditory stressor. Treatment with alprazolam resulted in a significant reduction of stress-induced increase of virus titters and pulmonary vascular permeability. A correlation with the lethality of mice was also observed.