Seroepidemiological survey of Bordetella bronchiseptica and canine parainfluenza-2 virus in dogs in Sweden.

The prevalence of antibodies against Bordetella bronchiseptica and canine parainfluenza-2 virus (CPiV-2) was investigated in a population of 302 pet dogs in Sweden. Sera were analysed for B bronchiseptica-specific immunoglobulin G by means of an ELISA, and for CPiV-2 specific neutralising antibody by means of a haemagglutination inhibition test. B bronchiseptica had a seroprevalence of 22 per cent and CPiV-2 had a seroprevalence of 28 per cent. The two pathogens did not appear to circulate together. The crowding of dogs together was significantly associated with the seroprevalence of CPiV-2, but not with the seroprevalence of B bronchiseptica. The dogs' ages, gender or their Fédération Cynologique Internationale breed group affiliation was not correlated with the seroprevalence of either pathogen.

New diseases and increased risk of diseases in companion animals and horses due to transport.

Dogs and horses are transported within the European Union for a number of reasons. The transport per se may cause physical problems, exemplified by hyperthermia in dogs and pleuropneumonia in horses, and the stress may reactivate latent infections such as canine herpesvirus-1 and equine herpesvirus-1. Preventive treatments are vital to protect dogs from ticks and mosquitoes transmitting their potentially lethal infectious agents, such as Leishmania donovani infantum, Babesia canis, Ehrlichia canis, and Dirofilaria immitis. However, records show that the travelling dogs are not fully protected since cases occur in non-endemic regions. The brown dog tick also poses a risk for humans by transmitting Rickettsia conorii causing Mediterranean spotted fever. Further, the trade in stray dogs from southern Europe has placed a particular focus on the occurrence of vector-borne diseases in the Mediterranean basin. The unknown origin of strays also poses a risk for rabies. With respect to horses, those transported to southern Europe may be exposed to Theileria equi and Babesia caballi, both of which are transmitted by ticks. Horses with antibodies against these parasites are not permitted to enter the USA. Additionally, viral diseases such as African horse sickness, transmitted by midges, and Borna disease, of the mode of transmission is yet unclear, may also pose a risk for horses travelling to potentially endemic regions.

Astrovirus epidemiologically linked to pre-weaning diarrhoea in mink.

Diarrhoea and excessive secretion from the cervical apocrine glands in young, suckling mink kits is a well-known, but poorly defined, syndrome often referred to as "sticky", "greasy", or "wet" kits. We have performed a case-control study, at farm level as well as at mink kit level, in Denmark and Sweden to investigate whether enteric virus infections may be a risk factor in the development of pre-weaning diarrhoea. Tissue samples from the enteric tract of 180 sacrificed mink kits were analysed histologically. Faecal contents were examined by electron microscopy (EM). Astrovirus was detected in abundance and found to be a significant risk factor both at farm level (OR=21.60, p<0.001) and at mink kit level (OR=7.95, p<0.001). Other factors, i.e. low body weight, coccoid bacteria adherent to the enteric villi, and presence of calicivirus were also shown to increase the risk of pre-weaning diarrhoea, although with less impact than astrovirus.

Sick-listing habits among general practitioners in a Swedish county.

OBJECTIVE: To describe sick-listing habits in general practice, how common it is and for how long and for what diagnoses it is granted. DESIGN: Medical audit study. SETTING: Primary health care. SUBJECTS: 53 general practitioners (GPs) registering all cases during a 2-week period when sick-listing was considered. MAIN OUTCOME MEASURES: Percentage of GP consultations that involved sick-listing, number of days of certified sick-leave, percentage of partial sick-listing, GP sex differences. RESULTS: 9% of all consultations included a consideration about sick-listing, and in only 6% of these instances was a certificate not issued. The median length of the certified sickness period was 14 days. Musculoskeletal problems were by far the most common diagnosis. Female patients were more often partially sick-listed than males. Female GPs sick-listed a larger proportion of their patients than male GPs. Risk factors for long certification periods were in fact associated with long certification periods. Even in cases where the GP would not recommend sick-listing a certificate was issued in 87%. CONCLUSIONS: Patients appear to have a strong influence on sick-listing practice, and there are important sex differences among GPs in this practice.

Studies on influenza viruses H10N4 and H10N7 of avian origin in mink.

An influenza A virus, A/mink/Sweden/84 (H10N4), was isolated from farmed mink during an outbreak of respiratory disease, histopathologically characterised by severe interstitial pneumonia. The virus was shown to be of recent avian origin and closely related to concomitantly circulating avian influenza virus. Serological investigations were used to link the isolated virus to the herds involved in the disease outbreak. Experimental infection of adult mink with the virus isolate from the disease outbreak reproduced the disease signs and pathological lesions observed in the field cases. The mink influenza virus also induced an antibody response and spread between mink by contact. The same pathogenesis in mink was observed for two avian influenza viruses of the H10N4 subtype, circulating in the avian population. When mink were infected with the prototype avian H10 influenza virus, A/chicken/Germany/N/49, H10N7, the animals responded with antibody production and mild pulmonary lesions but neither disease signs nor contact infections were observed. Detailed studies, including demonstration of viral antigen in situ by immunohistochemistry, of the sequential development of pathological lesions in the mink airways after aerosol exposure to H10N4 or H10N7 revealed that the infections progress very similarly during the first 24h, but are distinctly different at later stages. The conclusion drawn is that A/mink/Sweden/84, but not A/chicken/Germany/N/49, produces a multiple-cycle replication in mink airways. Since the viral distribution and pathological lesions are very similar during the initial stages of infection we suggest that the two viruses differ in their abilities to replicate and spread within the mink tissues, but that their capacities for viral adherence and entry into mink epithelial cells are comparable.

Variations in sick-listing practice among male and female physicians of different specialities based on case vignettes.

OBJECTIVE: To analyse the influence on sick-listing of speciality and sex of the prescribing doctor and of patients' way of presenting their problem. DESIGN: A sample of 360 general practitioners (GPs), 180 psychiatrists and 180 orthopaedic surgeons were presented case vignettes and asked to fill in a sick certificate for each case. The cases were chosen to reflect common causes of sick-listing in Sweden. The vignettes for each case were presented in three versions with uniform biomedical information plus a variation in the patient's attitude to sick-listing. SETTING: Swedish general practice and hospital physicians. MAIN OUTCOME MEASURES: Proportion of cases not being sick-listed and costs for the period certified. RESULTS: The most important factor affecting sick-listing was the patient's attitude to sick-listing. Patients wishing sick-listing were sick-listed to a greater extent than those who were reluctant. In addition, GPs sick-listed more than orthopaedic surgeons and less than psychiatrists. Female doctors sick-listed more than male doctors, irrespective of speciality and patient attitude. CONCLUSION: Sick-listing is influenced by the physician's speciality and sex. Doctors are strongly influenced by how the patients present their problem.

Herd-based monitoring for tuberculosis in extensive swedish deer herds by culling and meat inspection rather than by intradermal tuberculin testing.

The effect of random slaughter and meat inspection as a tool to detect or eradicate tuberculosis in large, extensive deer herds in Sweden was evaluated. A computer spreadsheet model based on the Reed-Frost method was developed. Numbers of new infections and of infected deer slaughtered as well as probability of detecting tuberculosis or slaughtering all infected deer in a herd, were simulated. The model predicted that, given a 20% annual slaughter and that disease was introduced with one infected deer, the infection would be detected or eliminated in most herds (90%) after 15 years.

Effects on physicians' sick-listing practice of an administrative reform narrowing sick-listing benefits.

OBJECTIVE: To find out whether administrative changes regulating sick-listing benefits affect sick-listing practice among physicians in hospitals and primary health care. SETTING: New sick-listing cases from four social security offices in mid-Sweden. DESIGN: A natural experiment design was used with a sample of newly started sick-listed cases collected 6 months before a sick-listing reform and a further sample taken 6 months after. The data were collected in a 1-year follow-up period in both samples. MAIN OUTCOME MEASURES: Net days of sick-listing and percentage partial sick-listings. Compliance by doctors in providing information asked for in sickness certification forms. RESULTS: Doctors filled in the forms more completely after the reform than they did before it. There was an inverse correlation between completeness of information and length of sick-listing. When potential confounding factors were taken into account, no change was seen in the proportion of partial sick-listing, in the mean number of net days of sick-listing or in the distribution of length of sick-listing periods. The proportion of all sick-listings made by general practitioners increased. CONCLUSIONS: Administrative changes restricting sick-listing benefits did change some aspects of sick-listing practice but had no effect on length of sick-listing.

A Reed-Frost model of the spread of tuberculosis within seven Swedish extensive farmed fallow deer herds.

The within-herd transmission of tuberculosis, after introduction of infection, was evaluated in seven Swedish herds of farmed fallow deer. The evaluation was based on a subset of data obtained from a previous epidemiological investigation, comprising 13 tuberculosis-infected deer herds, with the purpose of tracing the source of infection. A computer spreadsheet model based on the Reed-Frost method was developed to estimate the number of new infections. For each herd, a k-value (the number of effective contacts made by an individual during a time period) was estimated through fitting the model to the observed incidence in each herd. We concluded that, despite the relatively short observation periods and uncertain tuberculosis incidence estimates for the observed herds, the k's obtained could be used to quantify the estimated spread of tuberculosis in extensive deer herds in Sweden.

Two avian H10 influenza A virus strains with different pathogenicity for mink (Mustela vison).

We compared two strains of avian influenza A viruses of subtype H10 by exposing mink to aerosols of A/mink/Sweden/3,900/84 (H10N4) naturally pathogenic for mink, or A/chicken/Germany/N/49, (H10N7). Lesions in the respiratory tract during the first week after infection were studied and described. Both virus strains caused inflammatory reactions in the lungs and antibody production in exposed mink but only mink/84 virus was reisolated. The lesions caused by mink/84 virus were more severe with higher area density of pneumonia, lower daily weight gain, and more virus in the tissues detected by immunohistochemistry. The results indicate that mink/84 (H10N4), but not chicken/49 virus (H10N7), established multiple cycle replication in infected cells in the mink.

Dementia and driving: an attempt at consensus.

The number of older drivers in Sweden will be rapidly increasing during the next decades. A possible relationship exists between the increased relative crash risk of older drivers and the prevalence of age-related diseases such as dementia. However, a clear-cut policy for evaluating driving competence in demented persons is still lacking. In recognition of this fact, the Swedish National Road Administration invited a group of researchers to formulate a consensus on the issue of driving and dementia. This consensus document is aimed at providing primary care physicians with practical advice concerning the assessment of cognitive status in relation to driving. Suggestions are based on a review of existing research and discuss the use of general and driving-specific sources of information available to the physician. Consensus was reached on the statement that a diagnosis of moderate to severe dementia precludes driving and that certain individuals with mild dementia should be considered for a specialized assessment of their driving competence.

Molecular epidemiological studies of Mycobacterium bovis infections in humans and animals in Sweden.

Forty-nine isolates of Mycobacterium bovis from humans and animals in Sweden were analyzed by restriction fragment length polymorphism (RFLP) patterns probed by the insertion element IS6110. Most isolates had patterns indicating the presence of only one or two genomic copies of the IS6110 insertion element. This simple type of pattern was found in all human isolates. In contrast, isolates from M. bovis infections in five herds of farmed deer in Sweden showed a specific RFLP pattern with seven bands, indicating seven copies of the IS6110 sequence. In 1958, Sweden was declared free from M. bovis in cattle. However, in 1987, M. bovis was reintroduced with imported farmed deer, and since 1991, 11 outbreaks in deer herds, but not in other livestock or wildlife, have been diagnosed. Continued RFLP studies of the new Swedish M. bovis isolates can reveal possible transmission of this deer strain to other animals or humans.

Bovine tuberculosis in Swedish deer farms: epidemiological investigations and tracing using restriction fragment analysis.

Bovine tuberculosis was eradicated from Sweden after a programme lasting many years. By 1991, no tuberculosis in wildlife had been discovered for 50 years and the last case in cattle had occurred 13 years before. In 1991, the disease was identified in a herd of farmed fallow deer (Dama dama) and over the next three years nine other infected herds were identified. Investigation revealed that all the infected deer were either deer that had been imported into Sweden from the United Kingdom in 1987 or had been in contact with them. Restriction fragment analysis of eight isolates of Mycobacterium bovis from five of the herds showed that the isolates had identical patterns of DNA fragments, which indicated a common source of infection. Among more than 800 isolates of M bovis that have been analysed, these patterns were identical to those of only two previous isolates, both of which came from British deer. These results indicate that the eight Swedish strains of M bovis and the two British strains may have a common source of infection.

Binding of cholecystokinin and somatostatin to isolated porcine gastric mucosal cells and effects on aminopyrine uptake.

Mucosal cells were prepared by enzymatic digestion of porcine gastric mucosa with pronase and collagenase. The resulting cell suspension contained 10-15% parietal cells, which responded to histamine stimulation by an up to 20-fold increase in [14C]aminopyrine accumulation over control levels. Cholecystokinin-8 (CCK-8) evoked a more moderate stimulation of [14C]aminopyrine accumulation, whereas somatostatin inhibited histamine-stimulated accumulation. Parietal cells were enriched by elutriation and isopycnic centrifugation on density gradients of Percoll. A fraction with 60% parietal cells bound approximately three times more iodinated CCK-8 than a fraction containing 70% non-parietal cells. Binding of [125I]BH-CCK-8 to preparations containing 30-60% parietal cells was specifically inhibited to about 50% by 10(-9) M unlabelled CCK-8 but not by bombesin. Cell fractions containing about 30% parietal cells also bound [125I]somatostatin. Unlabelled somatostatin at 10(-9) M inhibited tracer binding by about 50%, while CCK-8 did not affect somatostatin binding to such a preparation. The results suggest the existence of specific receptors for CCK and somatostatin on porcine parietal cells exerting a regulatory influence on acid secretion.

Close relationship between mink influenza (H10N4) and concomitantly circulating avian influenza viruses.

Strains of an influenza H10N4 virus have been isolated during an outbreak of a respiratory disease in mink on the south-east coast of Sweden. This was the first example of a disease in mammals caused by the H10 subtype. We compared the A/mink/Sweden/84 strain with two recent avian H10N4 isolates, one from fowl and another from a mallard, both isolated in Great Britain in 1985 as well as the prototype A/chicken/Germany/N/49 (H10N7). The comparison was carried out by genomic analysis of the strains by oligonucleotide fingerprinting and in bioassays on mink. The oligonucleotide fingerprint analysis revealed a high degree of genomic homology of around 98% between the viruses from mink, mallard and fowl. Only the recent avian isolates, that from the mallard and fowl could infect mink by contact, causing similar pathological and clinical signs and inducing seroconversion as did the mink virus. However, the susceptibility of mink to the fowl and mallard viruses by contact was less pronounced than that to the mink virus. Both the genomic homology and the similarities from the infectivity and pathogenicity studies between the mink virus and the recent avian isolates point to a direct invasion of the mink population by an avian H10N4 virus.