Colonization properties of Campylobacter jejuni in chickens.

Campylobacter is the most common bacterial food-borne pathogen worldwide. Poultry and specifically chicken and raw chicken meat is the main source for human Campylobacter infection. Whilst being colonized by Campylobacter spp. chicken in contrast to human, do scarcely develop pathological lesions. The immune mechanisms controlling Campylobacter colonization and infection in chickens are still not clear. Previous studies and our investigations indicate that the ability to colonize the chicken varies significantly not only between Campylobacter strains but also depending on the original source of the infecting isolate. The data provides circumstantial evidence that early immune mechanisms in the gut may play an important role in the fate of Campylobacter in the host.

[Campylobacteriosis of man : livestock as reservoir for Campylobacter species]. / Die Campylobacteriose des Menschen : Nutztiere als Reservoir für Campylobacter-Arten.

Over the last few years, infections with Campylobacter have significantly increased in Europe and Germany and these bacteria have even surpassed Salmonella as the most prevalent bacteria, causing gastroenteritis. Especially contamination during the handling and consumption of meat products seems to be the most important risk factor which plays a prominent role for transmission to man. In addition, contact with pets and other animals, drinking raw or improperly pasteurized milk, and the tenacity of Campylobacter in different environments, especially water, have also to be considered for an adequate risk assessment. Besides gastroenteritis, arthralgia, and Guillain-Barré syndrome are important clinical complications of Campylobacter infections in man. At the same time, it is mostly unclear why the course of infection in man and in reservoir animals differs significantly, especially as only a few classical bacterial virulence factors have been identified so far. For these reasons, the development of efficient prevention strategies is of utmost importance in order to control campylobacteriosis.

Studies on the efficacy of different adjuvants in live stock specific bacterial vaccines for turkeys against Bordetella infection and onset of antibody titers in respect to the age of the turkey poults.

For evaluating the influence of the age of the vaccinated birds on the development of antibodies, five groups of turkey poults were inoculated subcutaneously at day 1, 7, 10, 14 and 21 of life with vaccine containing inactivated Bordetella avium and Freund's incomplete adjuvant. No matter which vaccine schedule was used, serum antibodies with the ELISA were first detected at the 28th day of life and increased continuously until the 49th day, when it exhibited either a peak or a plateau. Aluminium hydroxide, Freund's complete and incomplete adjuvant and a mineral oil-arlacel-tween-mixture being permitted adjuvants (appendix II EWG 2377/90) and the adjuvant Gerbu 100 were evaluated for their suitability. Turkeys were vaccinated at the age of three weeks and examined clinically as well as serologically up to the 11th week. Humoral antibodies were detected quantitatively using an ELISA for IgG and a microagglutination test for IgM and qualitatively using immunodiffusion. The damage at the application site was rated by measurement of the swelling of the tissue. In the 10th week, the animals were infected with the agent for challenge. The serological examination for IgG antibodies in the ELISA both treatments with Freund's adjuvants resulted in high titers, which differed significantly from the unvaccinated control after 21 days. IgM could be detected from day 7 onwards in all vaccinated groups and showed the highest titers when aluminium hydroxide was used as adjuvant. In the immunodiffusion assay, precipitating antibodies could be found from the first week after vaccination onwards. There was no correlation between the occurrence of precipitating antibodies and ELISA titers. The measurements of the swelling of the tissue in the beginning showed the largest swellings in the animals injected with Freund's incomplete adjuvant and differed significantly from the unvaccinated control. In the 10th week, the animals were infected with Bordetella avium for challenge. In comparison to the unvaccinated animals, all vaccinated turkeys, no matter which adjuvant was used, showed a distinct and significant reduction of the reisolation rate.

Influence of diet on the occurrence of some bacteria in the intestinal flora of wild and pet birds.

Enterobacteriaceae, E. coli in particular, do not belong to the intestinal flora of granivorous pet birds. This is indicated by the fact that the feces of only 9% of healthy budgerigars and 17% of finches tested were positive for enterobacteria. Stressful situations such as overcrowding in small cages coincident with increased noise and low light levels can enhance the colonization of the gut with E. coli. On the other hand it seems nearly impossible to colonize the intestine of budgerigars with E. coli or Klebsiella spp. even under favourable conditions. The frequent findings of enterobacteria in deceased granivorous birds suggest that E. coli and other enterobacteria are involved in the course of diseases with predisposing factors. Nutritional experiments with young chickens suggest that a diet consisting exclusively of seeds has an inhibitory effect on intestinal colonization with E. coli. Determination of Aeromonas hydrophila in nearly 3500 wild and pet birds provides statistically significant evidence that the composition of the intestinal flora may depend on dietary habits: infection was found in 1.9% of the granivorous and herbivorous species, in 7.1% of the omnivorous and in 12.4% of the carnivorous and insectivorous birds. The occurrence of enterobacteria and Aeromonas hydrophila in the digestive tract is obviously influenced by the composition of the nutrients.

[A modification of the in ovo-method for the determination of the antihemorrhagic activity of plant extracts]. / Eine Modifizierung der in ovo-Methode zur Ermittlung der antihämorrhagischen Aktivität von Pflanzenextrakten.

Up to now there has been only a method available for testing the antihaemorrhagic activity of plant extracts, in which chicken embryos had to be transferred to a special container on the fifth day of incubation. Furthermore, the test could not be conducted on the extraembryonal circulatory system until two days later. In the test method described here the embryos remain inside the egg. After removal of the eggshell through the air cell and removal of the inner shell membrane, direct access to the extraembryonal circulatory system is possible, minimising external influences on the test system. This represents a dramatic simplification in technique and permits testing already on the fourth day of incubation. The application of this method to determine the antihaemorrhagic properties of samples has the advantage of permitting the simple and quick production of haemorrhages by snake venom on the yolk sac circulatory system.

Comparative study of the plasma pharmacokinetics and tissue concentrations of danofloxacin and enrofloxacin in broiler chickens.

The plasma pharmacokinetics of danofloxacin and enrofloxacin in broiler chickens was investigated following single intravenous (i.v.) or oral administration (p.o.) and the steady-state plasma and tissue concentrations of both drugs were investigated after continuous administration via the drinking water. The following dosages approved for the treatment of chickens were used: danofloxacin 5 mg/kg and enrofloxacin 10 mg/kg of body weight. Concentrations of danofloxacin and enrofloxacin including its metabolite ciprofloxacin were determined in plasma and eight tissues by specific and sensitive high performance liquid chromatography methods. Pharmacokinetic parameter values for both application routes calculated by noncompartmental methods were similar for danofloxacin compared to enrofloxacin with respect to elimination half-life (t1/2: approximately 6-7 h), mean residence time (MRT; 6-9 h) and mean absorption time (MAT; 1.44 vs. 1.20 h). However, values were twofold higher for body clearance (ClB; 24 vs. 10 mL/min. kg) and volume of distribution at steady state (VdSS; 10 vs. 4 L/kg). Maximum plasma concentration (Cmax) after oral administration was 0.5 and 1.9 micrograms/mL for danofloxacin and enrofloxacin, respectively, occurring at 1.5 h for both drugs. Bioavailability (F) was high: 99% for danofloxacin and 89% for enrofloxacin. Steady-state plasma concentrations (mean +/- SD) following administration via the drinking water were fourfold higher for enrofloxacin (0.52 +/- 0.16 microgram/mL) compared to danofloxacin (0.12 +/- 0.01 microgram/mL). The steady-state AUC0-24 h values of 12.48 and 2.88 micrograms.h/mL, respectively, derived from these plasma concentrations are comparable with corresponding area under the plasma concentration-time curve (AUC) values after single oral administration. For both drugs, tissue concentrations markedly exceeded plasma concentrations, e.g. in the target lung, tissue concentrations of 0.31 +/- 0.07 microgram/g for danofloxacin and 0.88 +/- 0.24 microgram/g for enrofloxacin were detected. Taking into account the similar in vitro activity of danofloxacin and enrofloxacin against important pathogens in chickens, a higher therapeutic efficacy of water medication for enrofloxacin compared to danofloxacin can be expected when given at the approved dosages.

Isolation and identification of Vibrio metschnicovii from domestic ducks and geese.

Seven Vibrio-like field strains of German origin were isolated culturally from diseased domesticated ducks, muscovy ducks and geese, and were compared with reference strains NCTC 8443 (type strain) and NCTC 11170 of Vibrio metschnicovii using classical phenotypic and chemotaxonomic tests. Some V. cholerae strains were included in the chemotaxonomic tests for comparative purposes. On the basis of the classical phenotypic characteristics studied and the numerical analysis of the whole-cell fatty acid patterns, the Vibrio-like field strains were identified as Vibrio metschnicovii. The identification tables and the database of the computer software of two commercial micro-identification kits (API-20 NE, ID-32 E) did not identify the field strains. Of the reference strains used, only NCTC 8443 was correctly identified by the ID-32 E software.

Biotin-streptavidin enzyme-linked immunosorbent assay for the detection of antibodies to Campylobacter jejuni and C. coli in chickens.

An enzyme-linked immunosorbent assay (ELISA) was developed in a homologous system with bacterial ultrasonic-treated proteins as the antigen and antisera from chickens infected orally and subcutaneously with the strain Campylobacter jejuni serovar 6 (CJ 6). The cut-off level was determined using antisera from non-infected specific-pathogen-free chickens up to the age of 10 weeks. The suitability of the ELISA system was verified using antisera taken from chickens orally infected at the age of 4 weeks with CJ 1, 6, 28 or 36 or with Campylobacter coli serovar 28 (CC 28). The development of antibodies was monitored up to 6 weeks post-infection (p.i.). Sera from chickens infected with CJ 1, 6, 36 or CC 28 contained specific antibodies to Campylobacter, whereas in those infected with CJ 28 no specific antibodies were found. Distinct cross-reactions were observed between CJ 6, 28 and CC 28 antigens and their antisera 6 weeks p.i., while poor cross-reactions were found with antisera to CJ 1 and 28. Antibodies to strains of all heterologous serovars were successfully detected with an antigen pool comprised of CJ 1, 6 and 36 antigens. In 11 out of the 12 field sera obtained from 5- and 9-week-old broiler chickens suffering from campylobacteriosis, high specific antibody titres to Campylobacter jejuni were found.

Phenotypic characteristics of Riemerella anatipestifer and similar micro-organisms from various hosts.

A total of 199 Riemerella anatipestifer (RA) and RA-like field strains isolated culturally from birds of 12 different species and from pigs were characterized using classical phenotypic and chemotaxonomic tests. The RA reference strain ATCC 11845 was included in the study. On the basis of the classical phenotypic characteristics studied and the numerical analysis of the whole-cell fatty acid patterns, the RA reference strain and 123 field isolates were assigned to the indole negative (IN) variant and 10 isolates to the indole positive (IP) variant of the species RA. The IN strains were isolated not only from poultry and free-living wild ducks, but also from pigs, guillemots and from a budgerigar and a herring gull. All the IP isolates were isolated from domestic ducks. One field strain from a chicken and one from a black-headed gull, which were distinguished from RA mainly by the negative a-glucosidase reaction and production of yellow pigment respectively, showed fatty acid methyl ester profiles chemotaxometrically different from those of RA. Another 64 field strains isolated from domesticated ducks, geese and muscovy ducks with signs and lesions very similar to those caused by RA were phenotypically and chemotaxometrically clearly different from RA and could not be classified to any of the known species. This possible bacterial pathogen is therefore given the preliminary designation of Riemerella-like (RA-L) taxon 1502.

[Evaluation of different broiler housing conditions on the basis of clinical, pathological, anatomical and laboratory diagnostic criteria--a summary]. / Bewertung verschiedener Haltungsbedingungen von Broilern anhand klinischer, pathologisch-anatomischer und labordiagnosticher Kriterien-Eine zusammenfassende Darstellung.

In a cooperative study, the impact of different broiler housing conditions (see communication BUCHENAUER) on clinical, post-mortem and laboratory diagnostic (microbiological, parasitological, serological, immunological) parameters was investigated in the course of three different fattening period. Clinically, it was observed, that lower stocking densities allowed a relatively higher motility of the birds. On the other hand, necropsy findings, microbiological, parasitological, serological and immunological findings gave no indications that these parameters were influenced statistically significant by either one of the broiler keeping systems.

[Development of humoral precipitating antibodies to Campylobacter spp. in chickens]. / Entwicklung humoraler präzipitierender Antikörper gegen Campylobacter spp. beim Huhn.

Development of humoral precipitating antibodies against Campylobacter spp. in chickens. The development of precipitating antibodies in chickens was examined by two-dimensional immunodiffusion test after immunization with a formol inactivated vaccine and after subcutaneous and oral application of different live campylobacter serovars. The supernatant of bacterial cells after sonication and centrifugation was used as an antigen in the agar-gel precipitin test. Antisera against different campylobacter serovars showed a high percentage of cross-reactions. In chickens immunized with an inactivated vaccine at an age of 1, 2, 3, 4 and 7 weeks, precipitating antibodies could be demonstrated for the first time at 7 days p.i. Except for 1-week-old birds, sera from the other groups reacted positively at 14 days p.o. After subcutaneous duplication of live organisms to 4-week-old chickens, antibodies could already be demonstrated at 4 days p.i. later in part of the experimental groups. No interrelation could be detected between antibody titers, measured by enzyme-linked immunoabsorbent assay (ELISA), from precipitating sera, as well as from those from non-precipitating sera. Precipitating antibodies and antibody titers in the ELISA were examined in sera from groups of birds infected at an age of 1, 2, 3, 4 and 7 weeks. During the Campylobacter excretion period, a distinct peak of antibody titers occurred in 1- and 7-week old birds, whereas other groups showed a steady increase in titers. Precipitating antibodies were only found in 1- and 2-week-old chickens.

[Infectivity of Campylobacter jejuni and Campylobacter coli in chickens]. / Zur Infektiosität von Campylobacter jejuni und Campylobacter coli bei Hühnern.

The infectivity of four Campylobacter (C.) jejuni strains and one C. coli strain was evaluated by the reisolation rate from cloacal swabs after oral infection of chickens at four weeks of age. One strain did not colonize the digestive tract, another infected only a part of the experimental group and a third was excreted at a lower percentage in the first two weeks p.i. compared to the other two strains. In correlation to age, the excretion rate was highest in 7-week-old birds. In groups of 4 and 10-week-old chickens, the peak of the excretion rate appeared slightly delayed and on average, the excretion was lowest in 10-week-old individuals. A high correlation was found between the isolation rate of Campylobacters from cloacal swabs and from caecal contents.

[The distribution and persistence of Campylobacter spp. in chickens]. / Zur Verbreitung und Persistenz von Campylobacter spp. beim Huhn.

At the end of the production period, 29 layers each from 70 different flocks were examined for the occurrence of campylobacters in their caecal contents. All flocks were found campylobacter positive. Up to 20 individuals of 13 flocks and 21 to 29 birds of 57 flocks were carriers of Campylobacter spp. Material of the liver was additionally cultured from birds of 36 flocks. The isolation of the organism from livers was possible only from 1 to 6 birds of 16 flocks. In two experiments, chickens were infected at an age of 4 weeks with campylobacter strains inducing different excretion rate. The birds were infected again with a further campylobacter strain at 10 weeks of age. Birds at the same age which were not infected before, served as control. After this superinfection, the excretion of the organisms occurred at the same rate in all groups and did not depend on the strain chosen for the first infection. After an additional second superinfection in the second experiment, the period of excretion of the organism at a high rate was diminished.

Antigenic changes in Campylobacter spp. after adaptation to media with increased sodium chloride concentrations.

Campylobacter strains which were adapted to growth at 3% NaCl in the medium were examined for antigenic changes. The results of the immunodot blot, the immunoprecipitation test and the immunoblot demonstrate changes in the antigenic pattern. Heat-labile and heat stable antigens of the obtained salt-tolerants variants of Campylobacter type-strains showed differences from their parental strains after cross-absorption of antisera. Differences of the antigens between salt-tolerant variants and their salt-sensitive parental strains suggest that the antigenic structure of the flagellum and possibly of outer membrane proteins has been changed by adaptation of strains to higher salt concentrations.

NaCl-tolerance of Campylobacter isolates from birds and Campylobacter type strains and variation of their serological behaviour.

Growth on media containing 1.5% NaCl is one of the criteria for phenotypical differentiation of Campylobacter laridis from other thermophilic Campylobacter spp. Campylobacter isolates from birds and Campylobacter type strains could be adapted to growth at 3% NaCl within 19 to 72 subsequent passages on nutrient agar with increasing salt contents. The acquisition of salt-tolerance was stable after ten passages on media without salt and did not induce changes in other phenotypical characteristics. The results of slide agglutination demonstrate changes in the antigenic pattern of the Campylobacter strains after growth in salt. Heat-labile and heat-stable antigens of the salt-tolerant variants of Campylobacter type strains differed from those of the parent strains.

Occurrence of Campylobacter spp. in young gulls, duration of Campylobacter infection and reinfection by contact.

Two groups of three week old Herring Gulls (Larus argentatus) were held to observe the carrier state with Campylobacter. All 27 birds of group I excreted Campylobacter jejuni biotype III when they were caught from their colony. Four weeks later all but one were negative, indicating that the carrier state lasts until about the seventh week of life, with self-elimination if infection with another Campylobacter species is prevented by housing in a closed environment as in this study. Only one bird became reinfected one year later when gulls from group I were brought into contact with gulls from group II, consisting of ten freshly caught gulls, four of which were infected with the same biotype of Campylobacter, indicating that there might be some kind of immunity protection against infection with the same biotype of Campylobacter spp.

[Diseases and causes of death in native wild birds--a literature review]. / Krankheiten und Todesurachen bei einheimischen Wildvögeln--Eine Literaturübersicht.

Little attention was dedicated to diseases and causes of death of indigenous wild birds compared to poultry until recent decades. The interest of veterinary medicine in the spectrum of causes of morbidity and mortality of wild birds increased with the understanding of the importance of these birds as vectors in the epidemiology of zoonoses and as a biological indicator for the occurrence of substances noxious for the environment. The climate as a natural factor and the influences of civilization as traffic, high voltage lines and oil contamination of the sea lead to a reduction of bird species by starvation, traumata, intoxication and degenerative or proliferative and inflammatory or non inflammatory processes. Many parasitological, bacteriological, mycotic and viral diseases are wide spread among free living birds and make difficulties in keeping and breeding endangered birds.

[The occurrence of Campylobacter spp. and Salmonella spp. in gulls in northern Germany]. / Zum Vorkommen von Campylobacter spp. und Salmonella spp. bei Möwen in Norddeutschland.

Out of a total of 207 gulls--20 Black headed gulls, 185 Herring gulls and 2 Common gulls--128 (62%) and 23 (11%) birds, respectively, were infected with Campylobacter spp. (C.) and Salmonella spp. C. jejuni was predominant in gulls less than two years old (89%) and C. coli in older birds (75%). Furthermore, the infection rate with Campylobacters was depending on the habitats of the birds. The rate for C. jejuni and C. coli, respectively, was in gulls from regional garbage dumps 78% and 4%, from the coast 58% and 21%, and from islands 47% and 47% of the isolations in the corresponding area. Salmonellae were mainly isolated in the period from September to February from gulls less than one year old and from birds from the coast.

[The pathogenicity of Campylobacter jejuni as a monoinfection and as a mixed infection with Escherichia coli 078:K80 in broilers]. / Zur Pathogenität von Campylobacter jejuni als Monoinfektion und als Mischinfektion mit Escherichia coli O78:K80 bei Broilern.

Two week old broilers (n = 61) with a monoinfection with Campylobacter jejuni (0.5 ml of suspension containing 10(5) CFU/ml per os) showed reduced increase in weight during week 3 after infection compared to the control group. An other group of chickens (n = 31) was additionally infected with a suspension of Escherichia (E.) coli O78:K80 via drinking water from day 4 to 6 after the primary infection. This mixed infection provoked clinical signs of a disease and reduced increase in weight during the first two weeks of the experiment. Seven broilers of this group showed a fibrinous pericarditis and/or perihepatitis. Four of these chickens died. It can be concluded from the experiment that an infection with Campylobacter causes reduced weight gain and supports a systemic infection with E. coli.

Dermatitis in broilers caused by Escherichia coli: isolation of Escherichia coli from field cases, reproduction of the disease with Escherichia coli O78:K80 and conclusions under consideration of predisposing factors.

A dermatitis in broiler chickens, especially on the caudal back, thighs and around the cloaca is observed more frequently in the last years. The skin is swollen at sites of inflammation and a fibrineous plaque extends between muscle and subcutis. No clinical signs are visible in the living flock but the disease causes economical losses because of degrading and rejection of carcasses. Studies of literature and own field observations suggest that Escherichia (E.) coli is involved in the development of the dermatitis. The following serotypes were isolated from field cases: O78:K80 (3X), O2:K56 (2X), O127:K63 (3X), O9:K57 (1X), O140 (2X); two isolates could not be identified. The reproduction of the dermatitis was successful by infection via feather follicles with E. coli O78:K80. The density of broilers kept on farms may contribute to the outbreak of dermatitis by violation of the skin followed by infection of the injuries. Massage of the infected sites by close contact of birds and insufficient hygiene may support the development of the disease.