Diseases

Campylobacter

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Control Tools

  • Diagnostics availability

  • Commercial diagnostic kits available worldwide

    A range of tests are available mostly for testing food samples. Real time PCR tests are available as kits but need to be used within a laboratory. Real time PCR equipment has been developed and test results detecting low numbers of Campylobacter can be obtained within one hour. Polymerase chain reaction (PCR) - based assays have come into use, for example in Denmark, to screen broilers, and a commercial PCR-based assay is available for meat samples. It should be noted that PCR-based assays detect both viable and non-viable organisms. Antigen-capture enzyme-linked immunosorbent assays (ELISAs) have been described in the literature.

    Kits have been developed for the rapid species confirmation of Campylobacter.

  • Commercial diagnostic kits available in Europe

    Yes.

  • Diagnostic kits validated by International, European or National Standards

    BAX® System Real-Time PCR Assay for detection of C. jejuni, C. coli, and C. lari in poultry carcass rinses or processed products. The system is commercially available and has been validated by NordVal. It is performance tested and approved by AOAC. There is also a BioRad kit system IQ Check Campylobacter realtime PCR system for detection of Campylobacter in food samples. It has also AOAC approval.

  • Diagnostic method(s) described by International, European or National standards

    ISO 10272, published 2006, Microbiology of food and animal feeding stuffs - Horizontal method for detection and enumeration of Campylobacter spp. - Part 1: Detection method, Part 2: Colony-count technique A revision of the ISO is under progress and is planned to be published in 2016. ISO/FDIS 10272:2016 (E) Microbiology of the food chain — Horizontal method for detection and enumeration of thermotolerant Campylobacter — Part 1: Detection method, Part 2: Colony-count technique See OIE Manual of Standards for Diagnostic Tests and Vaccines: http://www.oie.int/fileadmin/Home/eng/Health_standards/tahm/2.09.03_CAMPYLO.pdf 
  • Commercial potential for diagnostic kits in Europe

    Depends on the potential and whether a legal obligation to screen animals and birds before slaughter will be implemented.

    On farm kits to allow scheduled slaughtering or the heat-processing/freezing of positive flocks. Flock screening tests should have specificity for detection of C. jejuni, C. coli, and possibly C. lari; unless a species specific confirmatory test is used prior to action. Specificity to Genus only may detect Campylobacters and related organisms of little public health importance, placing an undue burden on farm producers and the broiler industry.

    GAP: Rapid detection and identification tests on farm level are needed

  • DIVA tests required and/or available

    May be required if a vaccine is developed.

  • Opportunities for new developments

    The development of kits to rapidly identify colonised flocks

    The development of kits which detect (high levels of) colonisation in birds

    The development of rapid diagnostics for campylobacteriosis in humans

    GAP: Kits for rapid detection and quantification (also low levels) of Campylobacter in animals and in food products.

  • Vaccines availability

  • Commercial vaccines availability (globally)

    Under research only. There have been many indications that "Campylobacter spp. appear to be true commensals in broiler chickens. This, combined with high degree of genetic variability, presents challenges to vaccine development.

    GAP: No effective vaccines available for livestock.

  • Commercial vaccines authorised in Europe

    None

  • Marker vaccines available worldwide

    No

  • Marker vaccines authorised in Europe

    No

  • Effectiveness of vaccines / Main shortcomings of current vaccines

    Not applicable as no vaccines available.

  • Commercial potential for vaccines in Europe

    If a cheap effective vaccine was developed there could be market in the poultry industry to reduce the levels of Campylobacter in birds going for slaughter.

    The issues are

    • The short life of broilers
    • Vaccination of an immunologically immature animal
    • Vaccination in the presence of maternally-derived antibodies
    • Appropriate presentation at the gut mucosal surface
    • The absence of appropriate avian mucosal adjuvants
    • Cheap, easy delivery as oral vaccine or in ovo
  • Regulatory and/or policy challenges to approval

    None foreseen unless the vaccine is derived from a genetically manipulated organism.

    One vaccine under investigation is a GMO using a Salmonella as a vector of Campylobacter antigens.

  • Commercial feasibility (e.g manufacturing)

    Feasible, a market exists especially for free-ranging birds.

  • Opportunity for barrier protection

    No

  • Opportunity for new developments

    Develop a vaccine to prevent colonization of poultry in order to reduce levels of colonized animals going into abattoirs and the spread into the environment.

  • Pharmaceutical availability

  • Current therapy (curative and preventive)

    Antibiotic use not appropriate. Alternatives include bacteriophages and bacteriocins.

    GAP: Further research and development of curative and preventive therapies (excl antibiotics).    

  • Future therapy

    Antimicrobial resistance in these bacteria is an emerging and increasing threat to human health.    

    GAP: Development of therapy for humans (excl antibiotics).    

  • Commercial potential for pharmaceuticals in Europe

    None

  • Regulatory and/or policy challenges to approval

    Not applicable

  • Commercial feasibility (e.g manufacturing)

    None

  • Opportunities for new developments

    Experimentally, bacteriophages or bacteriocins have been reported to be effective if administered 3 days prior to slaughter. Early reports of potential application of bacteriocins to reduce colonization levels of Campylobacter spp. in broilers at slaughter were optimistic. However, there have been no reports in recent years of progress toward commercial scale trial application. Potential for development may still remain. Lately, reports have appeared that antimicrobial peptides could inhibit in vitro growth of Campylobacter which may be a way to reduce Campylobacter in broiler flocks. 

    GAP: Field trials needed to investigate effects and consequences of bacteriophages, bacteriocins or antimicrobial peptides.    

  • New developments for diagnostic tests

  • Requirements for diagnostics development

    Diagnostics should be standardized, fast and cheap.    

    GAPS: Development of rapid tests for the detection of live Campylobacter (for genus and species identification) in different types of samples, even present in low numbers. Rapid methods for the quantification of live Campylobacter.    

  • Time to develop new or improved diagnostics

    Long term.

  • Cost of developing new or improved diagnostics and their validation

    Expensive.

  • Research requirements for new or improved diagnostics

    None

  • Technology to determine virus freedom in animals

    Not available at present but would require a rapid screening method which could identify animals carrying Campylobacter in the intestines.

  • New developments for vaccines

  • Requirements for vaccines development / main characteristics for improved vaccines

    Two approaches are under investigation

    ·        Subunit vaccines using microsphere presentation systems or similar adjuvants

    ·        Genetically engineered Salmonella vector expressing various Campylobacter antigens

  • Time to develop new or improved vaccines

    Depending on when a candidate vaccine could be identified the timescale will be 5-10 years. Could be earlier if adjuvant problem solved.

    GAP: Problem with finding a suitable adjuvant.

  • Cost of developing new or improved vaccines and their validation

    Expensive with the need to develop and undertake all the relevant tests to provide data to enable the product to be authorised.

  • Research requirements for new or improved vaccines

    To investigate the immune mechanisms as immunity to Campylobacter appears to be strain-specific and complex, and the antigens conferring immunity are not well understood. This depends on the antigens under investigation. Most antigens have conserved as well as strain-specific and conformational as well as linear epitopes.

    In humans a candidate vaccine has been developed using an empirical approach. A vaccine consisting of heat- and formalin-killed whole bacteria combined with LT as a mucosal adjuvant has been developed by the Navy Medical Research Institute (USA) and shown to provide 87% protection against intestinal colonization in a small number of volunteers challenged post vaccination with a pathogenic Campylobacter strain. Current studies have focused on the use of flagellin or flagella-secreted protein FspA1 as candidate vaccines to be administered by the nasal route with attenuated LT R192G as an adjuvant. Vaccination of mice with FspA1 resulted in 64% protection against C. jejuni challenge. The major outer membrane protein (MOMP) from C. jejuni might be another promising candidate for a subunit vaccine, especially when made into proteoliposomes. An oral live multivalent vaccine expressing antigens from Campylobacter, Shigella and ETEC is also currently being developed as a travellers’ diarrhoea vaccine (see link below).

    http://www.freepatentsonline.com/6790446.pdf

    http://www.acebiosciences.com/index.php?option=com_content&view=article&id=55&Itemid=65

    One problem for vaccination of humans is the risk of induction of GBS. Recently strains have been selected as vaccine candidates to avoid this risk.

    In chickens the specificity of the immune response is not the same as in humans or other mammals. With the recent development of methods for delivering subunit vaccines Campylobacter antigens, selected on the basis of current knowledge and using post-genomic approaches can be tested as candidates in a challenge model.

  • New developments for pharmaceuticals

  • Requirements for pharmaceuticals development

    GAP: More information needed on susceptibilities to currently available antibiotics.

  • Time to develop new or improved pharmaceuticals

    Time to develop would depend on the product and the trials necessary to validate the test. Commercial production would then take further time.   

  • Cost of developing new or improved pharmaceuticals and their validation

    Costly.

Disease details

  • Description and characteristics

  • Pathogen

    Campylobacter is a genus of Gram-negative, microaerobic, slender, curved, motile bacteria with a single polar flagellum at one or both ends. Members of the genus Campylobacter can colonise a variety of habitats. The most important species in terms of food-borne disease are considered to be the Campylobacter species, C. jejuni and C. coli and the closely related C. lari. These species are often referred to as “thermotolerant”, due to their growth optimum at 42 °C. This analysis will focus on these agents only.

  • Variability of the disease

    The incubation period for campylobacteriosis is usually 2 to 5 days and the symptoms are mild to moderate. Most patients have prodromal fever followed by 3-7 days of diarrhea (mild to severe, sometimes frequent, explosive and bloody), abdominal pain, nausea and fever. The clinical symptoms of campylobacter infection are often indistinguishable from those caused by other enteric pathogens such as salmonella and shigella. Most cases of campylobacteriosis are self-limiting within a week, but some cases may require medical treatment including hospitalization. Post-infection complications include arthopathies, neuropathological symptoms (such as Guillain Barre Syndrome (GBS) and irritable bowel syndrome. The frequency of arthritis is low, and no correlations have been found between the severity of gastrointestinal symptoms and the development of Guillain-Barré syndrome.

    Both C. jejuni and C. coli have highly diverse populations but there is no known association between human disease presentation and strain variation excepting that some strain types are more frequently associated with GBS than others which appears to be related to antigen mimicry. C. jejuni/coli rarely cause disease in animals.

    GAPS: Host- factors involved in clinical picture need to be clarified. In practice, no animal model is available to mimic human disease and test pathogenicity of strains. 

  • Stability of the agent/pathogen in the environment

    In the laboratory Campylobacter species are very intolerant of drying, heat, freezing, UV, disinfectants, extremes of pH, etc. However, in natural environments C. jejuni and C. coli often survive for longer periods of time, depending on the surrounding conditions. Survival is supported by lower temperatures (4-10ºC), darkness and a moist atmosphere. The conditions that poultry meat is stored at for retail are ideal for survival as long as they are not frozen. Survival potential varies between strains and environmental stresses can affect host colonisation properties. Environmental stress can cause morphological changes from spiral to coccal. It may also render the organisms non-culturable but viable (VNC forms) though the importance of this to infection is as yet unknown. Coccal and VNC formation are independent events.

    The mechanisms of survival are unclear but common mechanisms present in other Gram negative bacteria are not present in the genome of Campylobacter.

    GAP: Markers of survival capacity required for informing risk assessments.    
  • Species involved

  • Animal infected/carrier/disease

    C. jejuni and C. coli can colonise the intestinal tract of most, if not all, mammals and birds. Also C. lari colonizes birds, including broilers and laying hens. In the laboratory C. jejuni and C. coli grow best at the body temperature of a bird (42 ºC), and seems to be well adapted to the avian gut. Poultry, especially chickens are colonised throughout their gastrointestinal tract and colonisation of the caecum can reach 1010 cfu per gram of caecal contents. These organisms can frequently be recovered from spleen and liver suggesting extra intestinal infection. Nevertheless this colonisation is asymptomatic and in experimentally challenged birds there are no obvious clinical signs or effect on production criteria.

    Campylobacter jejuni or C. coli may be recovered from animals with diarrhea but in the vast majority of cases this is more likely to reflect the washing out of commensal gut organisms due to other infections than to be causative of disease.

  • Human infected/disease

    The mechanisms of pathogenicity to induce diarrhea in humans are as yet unknown. A number of virulence properties have been described including mobility, adherence, invasion and cytolethal distending toxin (CDT) production. Strains vary in each of these properties but to date none have been able to account for the features of the disease. The major hindrance to understanding pathogenicity is the absence of a suitable animal model of disease.

    GAPS: 

    • Lack of animal model.
    • The only test of Koch’s postulates is experimental infections with purified organisms – this has been done with several volunteer studies for a limited number of organisms indicating a dose response relationship to colonization of humans but not to disease.
    • Evidence of markers confirming pathogenicity (virulence) is lacking 

  • Vector cyclical/non-cyclical

    Arthropods may act as mechanical vectors.

  • Reservoir (animal, environment)

    Campylobacter jejuni and C. coli are common asymptomatic gut colonisers of all warm-blooded animals including livestock, domestic pets and wildlife. The fastidious growth requirements for these organisms means that amplification only occurs within a host. Organisms are shed in faeces and survive to become ubiquitous in the environment, including in surface waters. Consequently Campylobacter is recovered from multiple potential reservoirs and is transmitted to humans and other animals by multiple potential routes and vectors.

    The reported prevalence of Campylobacter positive broiler flocks varies between countries. In Scandinavian countries prevalence is about 10% while in middle European countries e.g. the UK it is about 80% and in southern European countries it is about 100%. The prevalence of Campylobacter positive flocks also varies over season with summer peaks in most countries. Prevalence also varies with the production system, organic chicken and broilers in a production with outdoor access had a higher prevalence with up to 100%.

    Cattle, sheep and pigs are frequently colonised with Campylobacter; with prevalence at slaughter of about 50% to 90%.

    There is some host-specificity in these Campylobacter species. C. jejuni is commonly found in ruminants and poultry; C. coli is commonly found in pigs and poultry; while C. lari is most often found in wild birds.

  • Description of infection & disease in natural hosts

  • Transmissibility

    Transmission between hosts occurs via the faecal-oral route. Transmission from animals to humans is mainly through consumption and handling of contaminated animal food products or water and soil but also via direct contact with colonised animals.

    In broilers there is no detectable vertical transmission. The infective dose can be less than 10 cfu. Strains that are laboratory adapted are less infective. Transmission within a commercial broiler flock is very rapid and up to 100% of birds can become colonised within 5 days. Interestingly flocks are rarely infected until 2-3 weeks of age. This resistance to infection appears to be related to maternally-derived immunity although newly-hatched chicks can be colonised by challenges of less than 10 cfu.

    There is some evidence for Campylobacter strain-associated differences in colonisation potential in broilers. Little is known about the transmission between other livestock.

    GAPS:

    • Differences in colonisation potential (in broilers) need to be clarified.
    • Routes for transmission between other livestock than poultry have not been detailed.

  • Pathogenic life cycle stages

    Not applicable.

  • Signs/Morbidity

    Campylobacter colonisation in poultry is asymptomatic and in experimentally challenged birds there are no obvious clinical signs or effect on production criteria regardless of age.

    In young ostriches colonisation with C. jejuni can be associated with enteritis and occasional mortality but this is difficult to reproduce experimentally.

    In ruminants (cattle and sheep) both C. jejuni and C. coli are recovered from about 50% of asymptomatic animals at slaughter. However, in pregnant ruminants infection can occasionally cause abortion with organisms recovered from the abortion products. The incidence of abortion is low and appears to be dependent on the timing of infection. Abortion tends to occur late in gestation. Abortion induces immunity which is long lasting.

    Over 75% of pigs are asymptomatically C. coli and to a lesser extent C. jejuni positive at slaughter. Campylobacter-associated abortion in pigs has rarely been reported but abortion caused by a similar organism, Arcobacter, has been reported.

    Campylobacter jejuni and occasionally C. coli have been associated with enteritis in dogs, cats and other animal species, although rationally it could be causative, especially in juveniles and immunocompromised animals conclusive causative evidence is lacking.

  • Incubation period

    The incubation period in ruminants and pigs is unknown. In experimentally challenged chicks and older (2-3 weeks) birds become maximally colonised 1010 cfu per g caecal contents within 3 days.

     

  • Mortality

    There is no mortality associated with Campylobacter infection in chicks or chickens. The organisms are frequently recovered from the gut, liver and spleen of dead birds but the infection is not causative.

  • Shedding kinetic patterns

    In broilers shedding in faeces occurs detectably within 3 days of challenge. Colonisation is often chronic for the life of a conventional broiler (up to 7 weeks of age). Shedding can be erratic and is not a good indicator of colonisation. Colonisation can wane from 9 weeks after challenge which is thought to be associated with acquired immunity. However, some laying hens are still colonized in the caecum at slaughter (1.5 years old).    

    GAP: Quantitative data on shedding especially in free-range birds.

  • Mechanism of pathogenicity

    There is no known pathogenicity in broilers.

  • Zoonotic potential

  • Reported incidence in humans

    Campylobacter is a major cause of food-borne bacterial enteritis in humans worldwide. In 2014, Campylobacter continued to be the most commonly reported gastrointestinal bacterial pathogen in humans in the European Union (EU) and has been so since 2005. The number of reported confirmed cases of human campylobacteriosis was 236,851 with an EU notification rate of 71.0 per 100,000 population, a 9.6% increase compared with the rate in 2014. There is a significant underreporting of cases, hampering the possibility to calculate the total burden of the disease correctly. The cost of campylobacteriosis to public health systems and to lost productivity in the EU, has however been estimated by EFSA to be around EUR 2.4 billion a year. WHO refers to studies in high-income countries from which an annual incidence of campylobacteriosis between 4.4 and 9.3 per 1000 population were reported - the true incidence is however more poorly known in low income countries. The incidence is higher in children (aged 0- 4) and in young adults (15- 24). In 2014 Campylobacter species information was provided for 52.6% of confirmed cases reported in the EU, Iceland and Norway, which was a 9.4% increase in reporting compared with 2013 (48.1%). Of these, 81.8% were reported to be C. jejuni, 7.13% C. coli, 0.13% C. lari, 0.09% C. fetus and 0.07% C. upsaliensis. ‘Other’ Campylobacter species accounted for 10.6% but the large majority of those cases were reported at the national level as ‘C. jejuni/C. coli /C. lari not differentiated’.

    More information:

    From EFSA/ECDC:

    The European Union summary report on trends and sources of zoonoses, zoonotic agents and food-borne outbreaks in 2014, European Food Safety Authority/European Centre for Disease Prevention and Control:  http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/4329.pdf

    From WHO:

    http://apps.who.int/iris/bitstream/10665/80751/1/9789241564601_eng.pdf

  • Risk of occurence in humans, populations at risk, specific risk factors

    The vast majority of human cases (about 99%) are sporadic rather than outbreaks. However, outbreaks, or clusters of disease caused by consumption of poultry meat, unpasteurised milk and large water-borne outbreaks have been reported.

    The European Union summary report on trends and sources of zoonoses, zoonotic agents and food-borne outbreaks in 2014, European Food Safety Authority/European Centre for Disease Prevention and Control:  http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/4329.pdf

    Risk attribution studies have been undertaken using a variety of epidemiological methods. Epidemiological investigations, such as case-control and outbreak studies suggest that 20-40% of cases are attributable to the mishandling and consumption of not adequately cooked poultry meat. Scientific reports on risk factors for human infection indicate that the consumption of food (poultry meat, cross contaminated food products, raw milk and contaminated water) is the main source of infection, followed by direct contact with colonized animals.

    Strain typing has been also extensively used to determine risk attribution. Strain typing has been undertaken by multiple phenotypic and genotypic methods. However, over the last few years multi-locus sequence typing (MLST) has become routinely adopted in some laboratories for source attribution studies.  The principle behind MLST is that housekeeping genes are sequenced of which the combined results indicate statistically a degree of host specificity. Results from surveys where MLST have been used have hence given indications that 50-80% of the human campylobacteriosis cases could be attributable to poultry.  Poultry has further been divided into what is direct transmitted via meat, poultry faeces, contaminated water, soil and vegetables and indirect routes i.e. via from other animals including cattle, pigs and domestic pets. Combination of freezing of products from broiler flocks positive on-farm and enhanced biosecurity reduced incidence of domestically acquired campylobacteriosis in Iceland by 90%, indicating much higher attribution of human cases to fresh broiler chicken.

    Direct contact with colonised animals or material contaminated by their faeces may contribute to human campylobacteriosis.

    The relative importance of various reservoirs may vary between countries. Travel is also a major risk factor, but is a confounder for many factors such as different “reservoirs” and differences in immunostatus.

    Lately, whole genome sequencing has become a preferred technique for strain characterization (genotyping).

    GAP: Source attribution studies have only been performed in some countries. Difficult to get a clear picture, partly due to use of different methods (protocols) for strain characterization.

  • Symptoms described in humans

    In humans, C. jejuni or C. coli diarrhea is usually self-limiting. C. jejuni and occasionally C. coli cause enteritis and as few as 500 organisms have been reported to cause illness. The disease varies from mild gastrointestinal distress that resolves within 24 hours to a fulminating or relapsing colitis. The most common symptoms of infection include diarrhea, abdominal pain, fever, headache, nausea and vomiting. Symptoms usually start 2–5 days after infection, and last for 3–6 days. Relapses can occur in approximately 10-25% of cases.

    Complications are uncommon; however, reactive arthritis, haemolytic uremic syndrome and septicaemia can occur. Rare complications include meningitis, recurrent colitis, acute cholecystitis, massive lower gastrointestinal hemorrhage, mesenteric adenitis, appendicitis, and myopericarditis.  Cases of C. jejuni-associated abortion have been reported. Immunosuppressed individuals are at a high risk for severe or recurrent infections or for septicemia.

    Deaths are rare in C. jejuni infections and are seen mainly in patients with multiple diseases or other underlying conditions (eg cancer, AIDS, chronic liver disease). The estimated case/fatality ratio for C. jejuni infections is one in 1,000. The incidence of Guillain-Barré syndrome (GBS) per 100,000 population is 0.6- 1.9; up to 5 % of these patients may die and 30 % or more may have residual weakness or other neurologic defects. C. jejuni infection precedes onset in 20-50 % of all GBS cases.

  • Estimated level of under-reporting in humans

    The level of underreporting of campylobacteriosis is considered to be high for a number of reasons:

      (i) not all cases present to a general practioner,

      (ii) stool samples are rarely taken,

      (iii) detection of the causative agent is not optimal,

      (iv) not all confirmed cases are recorded.

      (v) policies differ between countries and regions

    It is estimated from community case control studies that the ratio of reported to unreported cases is 1:8 - 1:10.

    GAPS:

    • High level of underreporting of cases
    • Differences between countries in reporting practices

  • Likelihood of spread in humans

    Person-to-person transmission is unusual, but can occur if personal hygiene is poor and has been reported in nurseries and homes for elderly persons. C. jejuni is found in the faeces and can be shed for as long as 2 to 7 weeks in untreated infections. Although humans rarely become chronic carriers, some people have excreted C. jejuni for a year or more.

  • Impact on animal welfare and biodiversity

  • Both disease and prevention/control measures related

    There is no disease issue with chickens or the majority of livestock. Abortion in ruminants could happen but is infrequent. Control measures in conventional broilers currently only involve enhanced biosecurity.  Vaccination, bacteriophages and bacteriocins have all been suggested as control measures at the farm level and research is ongoing.

    GAP: Research required on vaccination, bacteriocins and bacteriophages as control measures. Further, more information on the effect of biosecurity measures under different climatic conditions is required. 

  • Endangered wild species affected or not (estimation for Europe / worldwide)

    Unlikely.

  • Slaughter necessity according to EU rules or other regions

    No.

  • Geographical distribution and spread

  • Current occurence/distribution

    The organisms are ubiquitous in animals and the environment worldwide. The disease affects humans worldwide.

  • Epizootic/endemic- if epidemic frequency of outbreaks

    Campylobacter is endemic in the world. In developing countries infection is usually limited to children, suggesting that a high level of exposure in early life or constantly exposed leads to the development of protective immunity.

    Sero-epidemiological studies in Europe suggest that exposure is also common in the developed countries when a person is being exposed at least once per year.

  • Seasonality

    Clear seasonal patterns of infection are seen in some countries, especially in northern countries but less so in temperate and warmer geographical areas. The seasonal peak in humans usually precedes the seasonal peak in prevalence of positive chicken flocks. Other livestock also have seasonal peaks though not necessarily at the same time. Better survival of Campylobacter during summer combined with the high density in commercial broiler farming favoring a rapid spread from one bird to another could be an explanation for the high Campylobacter prevalence, but the main driver of seasonality of Campylobacter remains elusive.

    GAP: Understanding of the basis of seasonality in humans and chickens is required.    

  • Speed of spatial spread during an outbreak

    Outbreaks in humans are rarely reported (less than 1% of all reported cases). In a large sentinel surveillance study in the UK, at the most 5% of cases were estimated to be associated with household outbreaks. Poultry-meat associated outbreaks can occur but tend to be due to multiple strains. However in one study at least 27% of human isolates implicated broilers as the source, and several clusters of disease were genetically and temporally matched with broiler isolates suggesting the potentials for outbreaks.

    Outbreaks have been mainly attributed to contaminated water or milk as point sources. Waterborne outbreaks tend to include large numbers of cases, last a short time and are usually related to failure in chlorination (or breakdowns at water plants)

    Colonisation in a broiler house is also considered as an outbreak. The rate of spread in these conditions is very rapid (about 3-5 days).

    GAP: Disagreement/ different opinion about the occurrence (and size of) of outbreaks in household and/or due to poultry meat. Could be due to differences in study design, different interpretation of data, and lack of harmonisation of typing methods 

  • Transboundary potential of the disease

    Spread to adjacent broiler houses is very rapid and common. Such spread occurs largely via human traffic (farmers etc) but might also occur through flies.

    Situation with transboundary spread is not relevant, but theoretically possible by international trade of colonized live animals.

  • Seasonal cycle linked to climate

    Studies indicate relationship between prevalence of flock positivity and temperature and/or rainfall.

  • Distribution of disease or vector linked to climate

    Most campylobacteriosis cases in humans are sporadic, peaking in the summer months. However, clear seasonal patterns of infection are identified in northern countries, but not in temperate and warmer geographical areas.

  • Outbreaks linked to extreme weather

    Heavy rainfalls may cause problems for water purification systems and lead to water-borne.

  • Sensitivity of disease or vectors to the effects of global climate change (climate/environment/land use)

    The geographical variation in the timing of the seasonal peak suggests that climate may be a contributing factor to Campylobacter transmission.

  • Route of Transmission

  • Usual mode of transmission (introduction, means of spread)

    Several hypotheses have been tested to explain how Campylobacter are introduced into broiler flocks. There is no evidence that vertical transmission exists, at least not in a significant way. The majority of flock colonisation result from horizontal transmission from the environment. Campylobacter can be easily spread from bird, or other animal, to bird through a number of routes including common water sources or through contact with infected faeces. Molecular epidemiology has demonstrated the presence of strain types in the poultry farm environment (i.e. in puddles or cattle) before the flock becomes positive with the identical type.

    Other livestock including cattle, sheep and pigs rapidly become Campylobacter positive after birth by acquiring infection from their dams. They also have maternally-derived immunity which appears to protect from disease. 

  • Occasional mode of transmission

    Arthropods may act as mechanical vectors for humans and livestock.

  • Conditions that favour spread

    For conventionally-reared broilers major risk factors include poor biosecurity, age of birds, season, multiple species farming, raising without all in-all out system (i.e. thinning) and free-ranging at any stage.  In some studies (possibly country related) drinking water is a risk factor.

  • Detection and Immune response to infection

  • Mechanism of host response

    In humans, volunteer studies have shown that protective immunity to Campylobacter enteritis occurs after primary infection but is short lived and strain specific. However, the epidemiology of disease in the developing world and in occupationally-exposured individuals clearly indicates that repeated exposure results in cross-reactive immune protection.  The human humoral immune response includes the rapid induction of anti-Campylobacter IgG, IgM, and IgA antibodies in serum, as well as secretory IgA from the intestinal mucosa, directed against a number of surface antigens including flagellin and the major outer membrane protein. Proinflammatory cytokines are also induced and there is an inflammatory response to infection in the intestinal mucosa. The self-limiting nature and rapid resolution of the disease in most humans suggests that this immune response is extremely effective. It has been suggested that the immune response contributes to the disease mechanism and that diarrhoea is an immunopathological event in humans.

    In chickens similar humoral and cellular immune responses occur though an inflammatory response is not seen. These responses have been well characterised. Nevertheless the colonisation is persistent suggesting that this immunity is poorly effective at eliminating the infection.

    There is little known about the immune responses to colonisation in other livestock.

    GAP: More research is required in this field.    

  • Immunological basis of diagnosis

    There are no serological assays in routine use for the detection of colonisation of C. jejuni/C. coli in livestock. However antigen-capture enzyme-linked immunosorbent assays (ELISAs) have been described in the literature for all host species. A standardised assay has recently been described in humans for use in sero-epidemiological studies.

  • Main means of prevention, detection and control

  • Sanitary measures

    Sanitation and management can help prevent colonization in intensively reared poultry. The main factor is biosecurity and all in-all out system, with decontamination of housing between flocks. This needs to include house-dedicated clothing, with changing of footwear, clothes and wash hands before entering the broiler house. Particular focus on visitors and catchers. High housing standards with a high level of tidiness in and around the broiler houses should be applied.

    Livestock such as cattle and pigs are often carriers of Campylobacter. Avoiding livestock at the farm or in the surroundings prevent transmission of Campylobacter into broiler houses via farm workers, especially if biosecurity is deficient or via vectors such as insects. Fly-screens have proved effective in some countries. Effectiveness of fly screening of ventilation inlets is most dramatic when applied in conjunction with careful broiler house entry biosecurity. Both flies and poor farm biosecurity can independently lead to high flock prevalence. Exclusion of rodents and other wild animals and wild birds and insect populations should also be controlled.

    Chlorination of drinking water may help prevent water-borne transmission. UV treatment of drinking water provides a more effective and low maintenance solution.

    GAP: Problems with implementing all biosecurity measurements and make the farmer fully aware of the need for the strict actions.

  • Mechanical and biological control

    Good hygiene and disinfection should be used to prevent spreading Campylobacter from one house to another by farmers or on fomites during an outbreak.

  • Diagnostic tools

    Two ISO (International Organization for Standardization) procedures for detection and enumeration of Campylobacter exist: a horizontal method for detection and enumeration of Campylobacter in food and animal feeding stuffs (ISO 10272 Part 1 and Part 2: 2006), and a procedure for the detection and enumeration of Campylobacter from water (ISO 17995). However, neither of these standard methods may be optimal for the isolation of campylobacters from live animals. An appendix to ISO 10272 on this topic is currently being developed and are planned to be published in the fall 2016.

    In mammals and birds, detection of intestinal colonisation is based on the isolation of the organism from faeces, rectal swabs and/or caecal contents. Agar media containing selective antibiotics are required to isolate these bacteria from faecal/intestinal samples. Alternatively, their high motility can be exploited using filtration techniques for isolation. Enrichment techniques to detect intestinal colonisation are not routinely used. Preliminary confirmation of isolates can be made by light microscopy. Under phase-contrast microscopy the organisms have a characteristic rapid corkscrew-like motility. Phenotypic identification is based on reactions under different growth conditions. Biochemical and molecular tests can be used to confirm various Campylobacter species. Polymerase chain reaction assays also can be used for the direct detection and identification of C. jejuni and C. coli.

  • Vaccines

    There are no effective vaccines available for the prevention of enteric Campylobacter colonization in birds or mammals. However, vaccination using Salmonella as a vector for Campylobacter antigens or subunit vaccines with appropriate mucosal adjuvants are under active research.

    GAP: Today there are no effective vaccines available for livestock (incl poultry).

  • Therapeutics

    Human cases are usually not treated with antibiotics unless patient is bacteraemic or disease develops into life threatening condition. Use of antibiotics enhances development of resistance.

  • Biosecurity measures effective as a preventive measure

    Appropriate cleaning and ventilation, safe handling of litter and manure, elimination of standing water around houses, appropriate use of house dedicated clothing, changing boots and safe handling and storage of feed. Prevention of the entrance of animals (including wild birds and insects) into poultry houses.

    The EU project CamCon has investigated different aspects and developed an on-farm educational program and a film with instructions about dos and don’ts: http://www.camcon-eu.net/

  • Border/trade/movement control sufficient for control

    Not appropriate.

  • Prevention tools

    No preharvest tools other than complying with all biosecurity measures including no thinning and flynet are available at present.

    GAP: Today there are no effective vaccines available for livestock (incl poultry).

  • Surveillance

    Surveillance is implemented in many countries but is not harmonized. One harmonized EU baseline survey of broiler flocks and broiler carcasses was carried out in 2008. Many national surveys have been conducted on poultry flocks, as well as cattle, sheep and pigs at slaughter. EFSA’s BIOHAZ Panel has published scientific opinions assessing the public health impact of control measures as well as a report presenting the economics related to different interventions which could be used to reduce the occurrence of Campylobacter in chickens and chicken meat. The experts also evaluated how reduction targets for Campylobacter in chickens in the European Union may lead to a fall in the number of human cases of campylobacteriosis associated with the consumption of chicken meat (www.efsa.europa.eu).

  • Past experiences on success (and failures) of prevention, control, eradication in regions outside Europe

    Difficult to control Campylobacter colonization in animals and birds using biosecurity alone. Nevertheless, decreasing prevalence are seen in some countries where biosecurity is implemented as part of a national action plan.

  • Disease information from the OIE

  • Disease notifiable to the OIE

    Only bovine genital campylobacteriosis caused by C. fetus subsp. venerealis is a reportable disease.

  • OIE disease card available

    No    

  • Socio-economic impact

  • Direct impact (a) on production

    No direct impact.

  • Direct impact (b) cost of private and public control measures

    Costs of biosecurity and hygiene practices in stables and abattoirs.

    GAP: Country specific costs.

  • Indirect impact

  • Trade implications

  • Impact on international trade/exports from the EU

    Nil, as it is not considered of major importance in trade regulation. The OIE Terrestrial Animal Health code only refers to bovine genital campylobacteriosis. There are no trade standards for other infections.

  • Impact on EU intra-community trade

    Nil at the moment, but performance objectives are discussed to be implemented in EU.

  • Impact on national trade

    Nil.

  • Main perceived obstacles for effective prevention and control

    • Persistence of the pathogens in animals
    • Persistence of the pathogen in the environment.
    • The need for strict biosecurity which is difficult to sustain
    • Difficulties of putting in place effective health education campaigns for consumers to prevent household cross-contamination
    • Multiple strains and molecular epidemiology poorly understood
    • Lack of effective vaccines or other on-farm measures.
    • EU legislation restricting use of post harvest chemical treatments
  • Main perceived facilitators for effective prevention and control

    • Effective vaccines or other effective on farm measures
    • Experimentally it has been shown that application of bacteriocins during the three days prior to processing reduces C. jejuni in faeces and is likely to similarly reduce on the processed broiler carcasses.
    • The use of bacteriophages may reduce the number shed by colonized birds.
    • Incentives for farmers to comply with biosecurity measures (e.g. higher price for compliance with biosecurity guidelines).

Risk

  • Campylobacter remains the main bacterial cause of foodborne disease in developed countries and has a major impact in the developing countries.

Main critical gaps

Conclusion

  • Campylobacter, are a major cause of food-borne bacterial enteritis in humans worldwide. In humans C. jejuni and C. coli are associated with campylobacteriosis which routinely presents as 3-5 days of prodromal fever followed by 3-7 days of acute diarrhea, abdominal pain and fever. The vast majority of human cases (about 99%) are sporadic rather than outbreaks. However, outbreaks, or clusters of disease caused by consumption of poultry meat, unpasteurized milk and large water-borne outbreaks have been reported.

    Appropriate cleaning and ventilation, safe handling of litter and manure, elimination of standing water around houses, appropriate use of house dedicated clothing and safe handling and storage of feed. Prevention of the entrance of animals (including wild birds and insects) into poultry houses.

    There are no effective vaccines available for the prevention of enteric Campylobacter colonization in birds or mammals. Nonetheless, regulatory and technical issues (production of large amounts) need to be solved.

Sources of information

  • Expert group composition

    Expert group members are included where permission has been given:

    Ingrid Hansson, National Veterinary Institute (SVA), Sweden - [Leader]

    Ruff Lowman, Canadian Food Inspection Agency, Canada

    Marianne Sandberg, the Danish Agriculture and Food council, Denmark

    Ihab Habib, School of Veterinary and Life Sciences, Murdoch University, Australia

    Eva Olsson Engval, National Veterinary Institute, Sweden

    Elina Lahti, National Veterinary Institute (SVA), Sweden

  • Reviewed by

    Project Management Board    

  • Date of submission by expert group

    June 2016