Bird attack on milk bottles: possible mode of transmission of Campylobacter jejuni to man

Population Genetics and Characterization of Campylobacter jejuni Isolates from Western Jackdaws and Game Birds in Finland

Poultry are considered a major reservoir and source of human campylobacteriosis, but the roles of environmental reservoirs, including wild birds, have not been assessed in depth. In this study, we isolated and characterized Campylobacter jejuni from western jackdaws (n = 91, 43%), mallard ducks (n = 82, 76%), and pheasants (n = 9, 9%). Most of the western jackdaw and mallard duck C. jejuni isolates represented multilocus sequence typing (MLST) sequence types (STs) that diverged from those previously isolated from human patients and various animal species, whereas all pheasant isolates represented ST-19, a common ST among human patients and other hosts worldwide. Whole-genome MLST revealed that mallard duck ST-2314 and pheasant ST-19 isolates represented bacterial clones that were genetically highly similar to human isolates detected previously. Further analyses revealed that in addition to a divergent ClonalFrame genealogy, certain genomic characteristics of the western jackdaw C. jejuni isolates, e.g., a novel cdtABC gene cluster and the type VI secretion system (T6SS), may affect their host specificity and virulence. Game birds may thus pose a risk for acquiring campylobacteriosis; therefore, hygienic measures during slaughter and meat handling warrant special attention.IMPORTANCE The roles of environmental reservoirs, including wild birds, in the molecular epidemiology of Campylobacter jejuni have not been assessed in depth. Our results showed that game birds may pose a risk for acquiring campylobacteriosis, because they had C. jejuni genomotypes highly similar to human isolates detected previously. Therefore, hygienic measures during slaughter and meat handling warrant special attention. On the contrary, a unique phylogeny was revealed for the western jackdaw isolates, and certain genomic characteristics identified among these isolates are hypothesized to affect their host specificity and virulence. Comparative genomics within sequence types (STs), using whole-genome multilocus sequence typing (wgMLST), and phylogenomics are efficient methods to analyze the genomic relationships of C. jejuni isolates.

Impact and management of Campylobacter in human medicine--European perspective

In 2001 in Germany, Campylobacter was second to Salmonella as the most frequent foodborne pathogen isolated from humans. This is also true for the major part of the European population with incidence data available, namely Germany, Hungary, Belgium, Denmark, Austria and Spain, with a total population of 154.5 million, and incidence rates for Salmonella and Campylobacter of 81.8/100 000 and 49.0/100 000 respectively. Countries where Campylobacter is predominant are the UK, Switzerland, Sweden, Finland, Norway, and The Netherlands, with a total population of 94.2 million, and incidence rates for Campylobacter and Salmonella of 79.6/100 000 and 33.3/100 000, respectively. Shigella is rarely isolated in Europe (1.9-4.5/100 000). Epidemiologic risk factors for human campylobacteriosis are poultry, untreated milk, and surface water. Travel plays an important role, especially in Scandinavia and the UK. Isolates acquired outside these countries are much more often resistant to fluoroquinolones than are domestic strains. Fluoroquinolone resistance in human Campylobacter isolates is lowest in the UK and Denmark, at 12%. Resistance quotes of around 20-40% are found in Finland, The Netherlands, Norway, Sweden, Austria, and Germany, and peaks in Spain reaching 70-80%. Usually, uncomplicated Campylobacter enteritis is symptomatically treated. If, in severe cases, antimicrobials are indicated, in all European countries except Switzerland, macrolides are used as first-line drugs, followed by fluoroquinolones or doxycycline.

Molecular epidemiology and characterization of Campylobacter spp. isolated from wild bird populations in northern England

Campylobacter infections have been reported at prevalences ranging from 2 to 50% in a range of wild bird species, although there have been few studies that have investigated the molecular epidemiology of Campylobacter spp. Consequently, whether wild birds are a source of infection in humans or domestic livestock or are mainly recipients of domestic animal strains and whether separate cycles of infection occur remain unknown. To address these questions, serial cross-sectional surveys of wild bird populations in northern England were carried out over a 2-year period. Fecal samples were collected from 2,084 wild bird individuals and screened for the presence of Campylobacter spp. A total of 56 isolates were recovered from 29 birds sampled at 15 of 167 diverse locales. Campylobacter jejuni, Campylobacter lari, and Campylobacter coli were detected by PCR, and the prevalences of different Campylobacter spp. in different avian families ranged from 0% to 33%. Characterization of 36 C. jejuni isolates by multilocus sequence typing revealed that wild birds carry both livestock-associated and unique strains of C. jejuni. However, the apparent absence of unique wild bird strains of C. jejuni in livestock suggests that the direction of infection is predominantly from livestock to wild birds. C. lari was detected mainly in wild birds sampled in an estuarine or coastal habitat. Fifteen C. lari isolates were analyzed by macrorestriction pulsed-field gel electrophoresis, which revealed genetically diverse populations of C. lari in Eurasian oystercatchers (Haematopus ostralegus) and clonal populations in magpies (Pica pica).

The animal-human interface and infectious disease in industrial food animal production: rethinking biosecurity and biocontainment

Understanding interactions between animals and humans is critical in preventing outbreaks of zoonotic disease. This is particularly important for avian influenza. Food animal production has been transformed since the 1918 influenza pandemic. Poultry and swine production have changed from small-scale methods to industrial-scale operations. There is substantial evidence of pathogen movement between and among these industrial facilities, release to the external environment, and exposure to farm workers, which challenges the assumption that modern poultry production is more biosecure and biocontained as compared with backyard or small holder operations in preventing introduction and release of pathogens. An analysis of data from the Thai government investigation in 2004 indicates that the odds of H5N1 outbreaks and infections were significantly higher in large-scale commercial poultry operations as compared with backyard flocks. These data suggest that successful strategies to prevent or mitigate the emergence of pandemic avian influenza must consider risk factors specific to modern industrialized food animal production.

Longitudinal study of the molecular epidemiology of Campylobacter jejuni in cattle on dairy farms

Multilocus sequence typing (MLST), an accurate and phylogenetically robust characterization method for population studies of Campylobacter, was applied to Campylobacter jejuni isolates (n = 297) from the fecal samples of cattle from five dairy farms in Cheshire, United Kingdom, collected throughout 2003. The population dynamics of the C. jejuni strains, as identified by the occurrence of sequence types and clonal complexes, demonstrated variations within and between cattle populations over time. Three clonal lineages have emerged to predominate among the cattle isolates, namely, the ST-61 complex (24.2%), ST-21 complex (23.6%), and ST-42 complex (20.5%). This provided further evidence that the ST-61 clonal complex may present a cattle-adapted C. jejuni genotype. In addition, the ST-42 clonal complex may also represent an important cattle-associated genotype. Strong geographical associations for these genotypes were also found among the farms. This is the first longitudinal study and the largest study to date for C. jejuni involving cattle populations using MLST for accurate strain characterization. This study shows the important associations between cattle and C. jejuni clonal complexes ST-61, ST-21, and ST-42, and it suggests that cattle and/or dairy products are likely to be a source of the human Campylobacter gastroenteritis caused by such genotypes. The reported findings have significant implications for the design of effective intervention strategies for disease control and prevention.

Environmental survival mechanisms of the foodborne pathogen Campylobacter jejuni

Campylobacter spp. continue to be the greatest cause of bacterial gastrointestinal infections in humans worldwide. They encounter many stresses in the host intestinal tract, on foods and in the environment. However, in common with other enteric bacteria, they have developed survival mechanisms to overcome these stresses. Many of the survival mechanisms used by Campylobacter spp. differ from those used by other bacteria, such as Escherichia coli and Salmonella spp. This review summarizes the mechanisms by which Campylobacter spp. adapt to stress conditions and thereby increase their ability to survive on food and in the environment.

Climate variability and campylobacter infection: an international study

Campylobacter is among the most important agents of enteritis in developed countries. We have described the potential environmental determinants of the seasonal pattern of infection with campylobacter in Europe, Canada, Australia and New Zealand. Specifically, we investigated the role of climate variability on laboratory-confirmed cases of campylobacter infection from 15 populations. Regression analysis was used to quantify the associations between timing of seasonal peaks in infection in space and time. The short-term association between weekly weather and cases was also investigated using Poisson regression adapted for time series data. All countries in our study showed a distinct seasonality in campylobacter transmission, with many, but not all, populations showing a peak in spring. Countries with milder winters have peaks of infection earlier in the year. The timing of the peak of infection is weakly associated with high temperatures 3 months previously. Weekly variation in campylobacter infection in one region of the UK appeared to be little affected by short-term changes in weather patterns. The geographical variation in the timing of the seasonal peak suggests that climate may be a contributing factor to campylobacter transmission. The main driver of seasonality of campylobacter remains elusive and underscores the need to identify the major serotypes and routes of transmission for this disease.

Prevalence of Campylobacter jejuni, Campylobacter lari, and Campylobacter coli in different ecological guilds and taxa of migrating birds

A total of 1,794 migrating birds trapped at a coastal site in southern Sweden were sampled for detection of Campylobacter spp. All isolates phenotypically identified as Campylobacter jejuni and a subset of those identified as non-C. jejuni were identified to the species level by PCR-based techniques. C. jejuni was found in 5.0% of the birds, Campylobacter lari was found in 5.6%, and Campylobacter coli was found in 0.9%. An additional 10.7% of the tested birds were infected with hippurate hydrolysis-negative Campylobacter spp. that were not identified to the species level. The prevalence of Campylobacter spp. differed significantly between ecological guilds of birds. Shoreline-foraging birds feeding on invertebrates and opportunistic feeders were most commonly infected (76.8 and 50.0%, respectively). High prevalence was also shown in other ground-foraging guilds, i.e., ground-foraging invertebrate feeders (11.0%), ground-foraging insectivores (20.3%), and plant-eating species (18.8%). Almost no Campylobacter spp. were found in ground-foraging granivores (2.3%), arboreal insectivores (0.6%), aerial insectivores (0%), or reed- and herbaceous plant-foraging insectivores (3.5%). During the autumn migration, a high proportion of samples from juveniles were positive (7.1% in passerines, 55.0% in shorebirds), indicating transmission on the breeding grounds or during the early part of migration. Prevalence of Campylobacter spp. was associated with increasing body mass among passerine bird species. Furthermore, prevalence was higher in short-distance migrants wintering in Europe than in long-distance migrants wintering in Africa, the Middle East, or Asia. Among ground-foraging birds of the Muscicapidae, those of the subfamily Turdinae (i.e., Turdus spp.) showed a high prevalence of Campylobacter spp., while the organism was not isolated in any member of the subfamily Muscicapinae (i.e., Erithacus and Luscinia). The prevalence of Campylobacter infection in wild birds thus seems to be linked to various ecological and phylogenetic factors, with great variations in carriership between different taxa and guilds.

Wild animals as reservoirs of infectious diseases in the UK

This review aims to illustrate the extent to which wildlife act as reservoirs of infectious agents that cause disease in domestic stock, pet and captive animals and humans. More than 40 agents are described. In the case of some of these, e.g. Cryptosporidium spp., Escherichia coli O157 and malignant catarrhal fever, the current evidence is that wildlife either does not act as a reservoir or is of limited importance. However, in the case of many important diseases, including bovine tuberculosis, Weil's disease, Lyme disease, avian influenza, duck virus enteritis and louping ill, wild animals are considered to be the principal source of infection. Wildlife may be involved in the epidemiology of other major diseases, such as neosporosis, Johne's disease, mucosal disease and foot and mouth disease, but further studies are needed. The UK would benefit from a more positive approach to the study of wildlife and the infections they harbour.

Canada goose (Branta canadensis) droppings as a potential source of pathogenic bacteria

Canada goose droppings, collected in parks to which the public had access, were screened for a range of bacteria that could be pathogenic in man. Droppings of Canada geese, and other waterfowl, did contain such bacteria, including some that are well-known causes of illness in man. These bacteria, plus a species of Salmonella that was experimentally inoculated into droppings, were shown to survive and multiply in the droppings for up to one month after their deposition by geese. Canada geese ranged further from water than other waterfowl species and thus distributed their droppings over a larger area of park grassland. This more widespread distribution of their droppings leads Canada geese to pose a greater potential health risk than other waterfowl studied here, but variations in human responses to challenge with bacteria, and variations in human and waterfowl behaviour in public parks, renders quantification of this risk impossible.

Acute and chronic neuropathies: new aspects of Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, an overview and an update

During the last 15 years new information about clinical, electrophysiological, immunological and histopathological features of acute and chronic inflammatory neuropathies have emerged. Thus, the Guillain-Barré syndrome (GBS) is no longer considered a simple entity. Subtypes of the disorder besides the typical predominant motor manifestation, are recognized, i.e. a cranial nerve variant with ophthalmoplegia, ataxia and areflexia, an immune-mediated primary motor axonal neuropathy (AMAN), and a motor-sensory syndrome (AMSAN). Also, the clinical pattern of GBS is related to preceding viral or bacterial infections. Two types of acute motor paralysis have been described, one with slow and incomplete recovery, another with recovery times identical with acute inflammatory demyelinating polyneuropathy (AIDP). Histologically, the first is characterized by Wallerian degeneration of motor roots and peripheral motor nerve fibres. In the latter anti-GM antibodies bind to the nodes of Ranvier producing a failure of impulse transmission. Motor-point biopsies have shown denervated neuromuscular junctions and a reduced number of intramuscular nerve fibres. Molecular mimicry has been postulated as a possible mechanism triggering GBS. Thus, in the cranial variant antibodies to ganglioside GQ1b recognizes similar epitopes on Campylobacter jejuni strains and similar observations apply to anti-GM1 antibodies. Chronic inflammatory demyelinating polyneuropathy (CIDP) also has several different clinical presentations such as a pure motor syndrome, a sensory ataxic variant, a mononeuritis multiplex pattern, relapsing GBS, and a paraparetic subtype. Each of the acute and the subtypes have different, more or less distinct, electrophysiologic and pathological findings. Instructive patient stories are presented together with there electrophysiologic and biopsy findings.

Campylobacteriosis in New Zealand: results of a case-control study

STUDY OBJECTIVE

To identify and assess the contributions of major risk factors for campylobacteriosis in New Zealand.

DESIGN

Case-control study. Home interviews were conducted over nine months using a standardised questionnaire to assess recent food consumption and other exposures.

SETTING

Four centres in New Zealand with high notification rates of campylobacter infections--Auckland, Hamilton, Wellington, and Christchurch.

PARTICIPANTS

Case patients were 621 people notified between 1 June 1994 and 28 February 1995 as having campylobacter infection. Control subjects were selected randomly from telephone directories, and were matched 1:1 with case patients in relation to sex, age group, and home telephone prefix.

RESULTS

Risk of campylobacteriosis was strongly associated with recent consumption of raw or undercooked chicken (matched odds ratio 4.52, 95% confidence interval 2.88, 7.10). There was also an increased risk with chicken eaten in restaurants (matched odds ratio 3.85; 2.52, 5.88). Recent consumption of baked or roasted chicken seemed to be protective. Campylobacteriosis was also associated with recent overseas travel, rainwater as a source of water at home, consumption of raw dairy products, and contact with puppies and cattle, particularly calves.

CONCLUSIONS

Improperly cooked chicken seems to be associated with a large proportion of campylobacteriosis in New Zealand. Thorough cooking of chicken in homes and restaurants could reduce considerably the incidence of this disease.

Resistotyping of campylobacters: fulfilling a need

A 9-month trial of a simple typing scheme for ¿thermophilic' enteric campylobacter isolates at a large Public Health Laboratory is described. Resistotyping was performed with six agents in a method modified by Bolton and colleagues from an earlier scheme, and biotyping was performed by a modified Lior scheme involving three tests. Reproducibility was excellent in both schemes, with test variation < 2%. Five household clusters and one larger presumptive milk-borne outbreak were identified in this scheme, and confirmed in pyrolysis mass spectrometry. The 328 isolates from new patients, excluding duplication from these clusters, were divided into 35 resistotypes with the largest group comprising 22% of isolates. In combined bio- and resistotyping, 86 types were found, with the largest group comprising 9.5% of isolates. The results are contrasted with salmonella sero- and phage-typing, where, on the same basis, the 176 isolates in the same period were divided into 40 groups, with the largest comprising 45% of isolates. Resistotyping, with or without additional biotyping, proved to be a convenient, simple, rapid, highly discriminatory, reproducible and inexpensive method well suited to use in local laboratories. It is a strong candidate for first-line national and local surveillance of campylobacter infections, fulfilling a need for monitoring of this important cause of enteric disease.

The Public Health Laboratory Service national case-control study of primary indigenous sporadic cases of campylobacter infection

The aetiology of sporadic campylobacter infection was investigated by means of a multicentre case-control study. During the course of the study 598 cases and their controls were interviewed. Conditional logistic regressional analysis of the data collected showed that occupational exposure to raw meat (odds ratio [OR] 9.37; 95% confidence intervals [CI] 2.03, 43.3), having a household with a pet with diarrhoea (OR 2.39; CI 1.09, 5.25), and ingesting untreated water from lakes, rivers and streams (OR 4.16; CI 1.45, 11.9) were significant independent risk factors for becoming ill with campylobacter. Handling any whole chicken in the domestic kitchen that had been bought raw with giblets, or eating any dish cooked from chicken of this type in the home (OR 0.41-0.44; CI 0.24, 0.79) and occupational contact with livestock or their faeces (OR 0.44; CI 0.21, 0.92) were significantly associated with a decrease in the risk of becoming ill with campylobacter.

The seasonality of canine births and human campylobacteriosis: a hypothesis

The seasonality of canine births was investigated using records from the Kennel Club and the breeding centre for the Guide Dogs for the Blind Association. In these populations a distinct seasonal pattern was found with a greater number of puppies being born in the summer months than the winter. The hypothesis that the greater number of puppies acquired as pets during the summer months may contribute to the seasonal rise in human campylobacter cases, seen at this time, is discussed.

A point source outbreak of campylobacter infection related to bird-pecked milk

A point source outbreak of Campylobacter jejuni affected 11 children in a day nursery. Milk consumed by the children was known to have been pecked by magpies on occasions. Illness was significantly associated with consumption of milk on a single morning. Examination of milk from a bottle pecked after the outbreak yielded campylobacters. The level of contamination was approximately six cells of C. jejuni per 500 ml of milk.

Bacterial diarrhoea

Diarrhoeal disease caused by enteric bacterial pathogens has become less prevalent in industrialized countries, but remains an important cause of morbidity and mortality in developing countries. Although better management of acute diarrhoeal episodes has led to more favourable outcomes, persistent diarrhoea remains a problem for which risk factors are being recognized and associated bacterial pathogens identified. Unusual or intractable diarrhoea should alert health workers to the possibility of impaired immune function, which is associated with a range of enteric pathogens and opportunistic infections. Improved microbiological methods have resulted in more frequent detection of pathogens in association with diarrhoea, as well as greater understanding of pathogenesis. Clinical features of diarrhoeal disease and mechanisms involved in pathogenesis are discussed in relation to specific bacterial enteric pathogens.

Food-borne bacterial infections

The number of episodes of diseases caused by bacterial contamination of food has shown a real increase by about threefold in the last decade in the U.K. The numbers for 1992 are estimated to be 2 million. The causes are multifactorial and complex, and 4 representative pathogens are reviewed. The main increase in diseases due to salmonella has been caused by Salmonella enteritidis, especially from eggs. The commonest bacterial food pathogen is campylobacter, which causes an illness with specific season peaks in May and June. This may be related to the activities of birds and mammals. Both these bacteria cause common diseases that are rarely fatal. In contrast, Listeria and E. coli are ubiquitous but rarely produce disease; however, the consequences of any such illness are often dire. Procedures and techniques are available for the control of most of these diseases, but society does not seem determined to implement them.

Jackdaws and magpies as vectors of milkborne human Campylobacter infection

In 1990 we reported that milk bottles pecked by jackdaws and magpies were a probable source of human campylobacter infection. During April to June 1990 an extended study of campylobacter infections was carried out in the Gateshead area. Prior to the study a health education programme was undertaken in an attempt to reduce human infection. Fifty-nine cases of human infection were recorded and 52 were interviewed. Thirty were entered into a case control study which demonstrated a very strong association between consumption of pecked milk and human campylobacter infection (chi 2 = 12.6, P less than 0.0004). It was estimated that between 500 and 1000 jackdaws (Corvus monedula) were present in the area where milk bottles were pecked and 63 isolates of campylobacter were made from the bill and cloaca. Target bottles were put out in the early mornings and campylobacters were isolated from 12 of 123 pecked bottles. Typing of the campylobacters revealed a wide distribution of strains amongst birds, pecked milk and human infections. The health education programme had only limited success.

A study of risk factors for Campylobacter infection in late spring

A case-control study was carried out to investigate possible reasons for the large increase in the number of cases of infection caused by Campylobacter species reported in the Regional Epidemiology Section of Manchester Public Health Laboratory in late spring each year. The hypothesis tested was that a risk factor peculiar to campylobacter infection is responsible for this phenomenon. Interviews about a wide variety of risk factors were conducted with 29 patients suffering from campylobacter enteritis and 41 out of a control group of 42 with acute diarrhoeal illness from other causes. The only statistically significant association with campylobacter infection was having had milk bottle tops pecked by birds, while previously recognised associated factors such as outdoor activities, pet ownership and consumption of chicken showed no significant association. Interviewees identified the birds responsible as magpies.

Delay in diagnosis of childhood asthma and its influence on respiratory consultation rates

A survey of cases of asthma in two general practices with a special interest in the disease identified 212 asthmatic children aged 0-16 years by the end of January 1989 who had been registered in that practice since birth. Delay in diagnosis, both in terms of time (median 2.95 years) and number of consultations (median 7), was considerable. Annual rates of consultations for respiratory symptoms that were initiated by the patients fell significantly after diagnosis (median before = 1.80, after = 0.95 consultations/year), but the number initiated by the doctors rose significantly (median before = 0, after = 1.01 consultations/year). The overall rates before and after diagnosis were not significantly different (median before = 2.04, after = 2.21 consultations/year). Increased efforts are required to reduce this delay thereby minimising the morbidity of asthma in childhood.