Colibacillosis in caged layer hens: characteristics of the disease and the aetiological agent.

In Europe, outbreaks of acute mortality in layer flocks due to colisepticaemia have frequently been observed since the mid-1990s. The aims of this study were to describe the disease, to identify the serotypes of the avian pathogenic Escherichia coli (APEC) present in these outbreaks, and to detect the presence of F11 fimbriae and flagella in the isolates. For this purpose, 20 flocks with APEC-associated increased mortality and 20 control flocks matched for age were examined. Weekly mortality rates in the colibacillosis-affected flocks reached 1.71%, versus 0.30% in the control flocks. The maximum cumulative mortality over an entire colibacillosis outbreak reached 9.19%. The disease was often flock and hen house associated, with recurrent outbreaks within one round and in successive rounds in the same house. Disease was usually acute without clinical symptoms. Peritonitis with yolk material deposited in the peritoneal cavity and polyserositis were the main lesions at necropsy. O78 strains were isolated in 15 of the 20 colibacillosis flocks, and in only one of the control flocks. The majority of strains from the control flocks could not be serotyped by the 28 O-antisera used. In general, F11 fimbriae and flagella were present in the majority of the strains. F11 fimbriae were significantly more often found in O78 isolates than in the other serotypes, and are thus more often present in isolates from colibacillosis flocks. Strains positive for F11, and for F11 and flagella, were more frequently present in heart and liver of the colibacillosis-affected flocks.     

Natural and experimental staphylococcal mastitis in rabbits

Two natural outbreaks of rabbit mastitis caused by a single phage-type of coagulase-positive staphylococcus were studied. The disease was characterized by abscess formation from which animals slowly recovered without development of immunity to subsequent infection.A vaccine containing the causal organism and its products failed to protect against the disease.When lactating does maintained under laboratory conditions were artificially infected either by injection or by suckling nasally colonized young, the disease produced was not always of the abscess type. Experimentally infected animals frequently died within 48 h. from a gangrenous spreading condition. Both abscess and gangrenous types of disease could be established with very low numbers of organisms.It may be concluded that staphylococcal mastitis in rabbits takes one of two clinical forms. One form is typified by abscess formation and is rarely fatal; the other appears as a gangrenous speading lesion which is frequently rapidly fatal. Since cows may contract both chronic and gangrenous staphylococcal mastitis, the rabbit appears to be a useful and inexpensive alternative test animal.     

Anaemia-dermatitis of broilers: Field observations on its occurrence, transmission and prevention

Anaemia-dermatitis was first observed in German broiler flocks in 1977. Its frequency has increased in the past six years. Atrophy of thymus, bursa and bone marrow occur and are affected by a severe anaemia and immunosuppression. Secondary bacterial infections of the skin cause gangrenous dermatitis. Systematic investigations of outbreaks in two broiler integrations showed the syndrome to occur only in the offspring of young broiler breeders during the first 3 to 9 weeks of production. Anaemia could be reproduced experimentally in CAA-antibody negative SPF birds by injecting a bacteria-free filtrate of organ homogenates of diseased birds; birds kept in contact with the inoculated chicks remained healthy. It is concluded that anaemia-dermatitis is primarily caused by the chicken anaemia agent (CAA). Vertical transmission via hatching egg predominates with no evidence of horizontal transmission. In order to prevent egg transmission of CAA immunisation during rearing is indicated for breeder stocks.     

Coligranulomatosis (Hjärre and Wramby’s disease) reconsidered

Coligranulomatosis (Hjärre and Wramby’s disease) is considered to be a disease of chickens, turkeys and partridges that occurs sporadically in individual, adult birds. Therefore, the condition is not of economic importance, but is of interest due to the similarity of its lesions to those of tuberculosis. In a number of cases the disease could be reproduced by inoculation via artificial routes of granuloma homogenate or Escherichia coli bacteria isolated from the lesions. Oral inoculations always failed. Occasionally, also serious outbreaks of granuloma disease have been reported in chickens, turkeys and quails. E. coli bacteria were either not isolated or isolated, but the disease could not be reproduced with the isolates, which means that the essence of Koch’s postulates was not fulfilled. Also other evidence of causality was not presented. Therefore, these disease cases might have been wrongly diagnosed as coligranulomatosis. Instead they may have been caused by Tetratrichomonas gallinarum, a parasite, which has the ability to induce severe granulomatosis in chicken flocks as has been shown recently. It is concluded that whenever severe granuloma disease is observed in poultry flocks at a large scale and is thus economically relevant, T. gallinarum should be included and rank high in the list of differential diagnoses.     

An update on the epidemiology of contact dermatitis in commercial broilers.

A computerized management and disease information retrieval system for commercial broiler production was established in 1985. The database presently contains information on over 950 flocks (15 million birds) per annum. The system has enabled the effectiveness of strategies which have been implemented to control contact dermatitis to be monitored. Between 1986 and 1994, the prevalence of breast burn lesions has been practically eradicated (0.2 to 0.00%) and the prevalence of hock burn lesions has been dramatically reduced from 21 to 7%. This reduction has been mainly due to the use of better litter management techniques and improvements in house design, particularly changing the type of drinker system. Production factors during 1993 and 1994 which were found to be consistently related to increased prevalence of hock burn lesions were male only flocks, inferior food conversion ratio, failure to meet target income and increased mortality rates.     

Epidemiology of a contact dermatitis of broilers

A computerised information retrieval system of broiler production data has been used to study the epidemiology of contact dermatitis. The results of the analyses of broiler production data for the period 1984/85 were compared and contrasted with those for the period 1986/1987.

The prevalence of breast lesions recorded in the latter period was 33% less than in the former. The prevalence of hock lesions was similar in both periods, but the degree of variation in the prevalence of lesions recorded by individual flocks was substantially reduced in 1986/87. Stocking density, average age of removal and the sex of birds all had an effect on the prevalence of the condition in broiler flocks in both time periods. The condition was more frequently recorded in flocks during the winter and a strong correlation with ambient relative humidity, obtained.     

Molecular epidemiology of Enterococcus cecorum isolates recovered from enterococcal spondylitis outbreaks in the southeastern United States

Enterococcus cecorum, a normal intestinal inhabitant, is increasingly responsible for outbreaks of arthritis and osteomyelitis in chickens worldwide. Enterococcal spondylitis (ES) is a specific manifestation of E. cecorum-associated disease in which increased flock morbidity and mortality result from chronic infection involving the free thoracic vertebra. In this study the genetic relatedness and antimicrobial resistance of isolates recovered from ES-affected flocks in the southeastern United States were determined. ES outbreaks from 2007 to 2011 were investigated in North Carolina (15 flocks, 13 farms, four integrators), South Carolina (one flock, one farm, one integrator) and Alabama (six flocks, six farms, one integrator). From these 22 epidemiologically distinct outbreaks, 326 isolates of E. cecorum were recovered. Isolates from spinal lesions and caeca of affected birds (cases) and caeca of unaffected birds (controls) were genotyped using pulsed-field gel electrophoresis; phenotyped using both GenIII MicroPlate? (Biolog; Hayward, CA, USA) microbial identification plates and antimicrobial sensitivity testing; and compared with each other. Isolates from spinal lesions were incapable of mannitol metabolism and the majority of these isolates were genetically clonal. In contrast, caecal isolates from control birds varied in their ability to metabolize mannitol and were genetically diverse. Isolates from both case and control birds had high levels of antimicrobial resistance. These findings indicate that the increase in E. cecorum-associated disease in the southeast United States is due to the emergence of new clones with increased pathogenicity and multidrug resistance.     

A contact dermatitis of broilers -epidemiological findings

Lesions of a contact dermatitis have resulted in serious downgrading of broiler carcases in the Northern Ireland poultry industry. A longitudinal survey was initiated to identify the important epidemiological factors involved in the occurrence of the condition. The results from the analysis of data from 986 flocks containing 12.6 million birds over a 2 year period, have quantified the effects which the major aspects of production have on the incidence of the condition in individual flocks. The stocking density, feed manufacturer, average age of removal and the sex of birds all had a profound effect. Lesions were more frequently recorded in flocks during the winter months and a strong correlation with the weather variable, relative humidity, obtained. Individual producers and houses varied in the incidence of the condition which was closely associated with the presence of poor litter conditions in the flocks.     

Risk factors associated with colibacillosis outbreaks in caged layer flocks.

Colibacillosis appears to be of increasing significance in layer flocks, but there have been no studies of the risk factors associated with outbreaks. This study aimed to investigate the possible associations between risk factors of non-infectious nature and outbreaks of mortality due to colibacillosis in flocks of caged layer hens. Information on management, biosecurity measures and housing conditions was collected in 20 flocks suffering from the disease and in 20 clinically healthy control flocks. The data were processed using multiple logistic regression. The statistical analysis demonstrated that an increase in the distance to the nearest poultry farm by 1 km was associated with a six-fold decreased risk of an outbreak of colibacillosis (odds ratio=0.16). Furthermore, a 1 l increase in cage volume per hen was associated with a 33% decrease in the risk of an outbreak (odds ratio=0.75). It was concluded that the distance between poultry farms and the hen density in the cages are important risk factors for outbreaks of colibacillosis in flocks of layer hens.     

Granuloma disease in flocks of productive layers caused by Tetratrichomonas gallinarum

In 2013, seven outbreaks of granuloma disease occurred in Dutch flocks of productive layers housed on different farms. These outbreaks were characterized by increased mortality and high incidence of granulomas, mainly in caeca (340/408 hens?=?83%) and livers (69/408 hens?=?17%). Mortality started to increase between 21 and 35 weeks of age and reached 3.7% to 11.0% exceeding the breeder's norm in periods ranging from 9 to 48 weeks. Some flocks also showed decreased egg production and/or loss of mean egg weight. All affected flocks were linked to one rearing farm, which therefore seemed to be the source of the disease. However, no signs of disease had been observed at this rearing farm. Sentinel hens placed in one of the affected flocks to determine whether the disease had an infectious nature developed granulomas identical to those seen in the outbreaks. Next, by fulfilling Koch’s postulates it was shown that Tetratrichomonas gallinarum was the aetiological agent of the granuloma disease. The condition was reproduced in mature specified pathogen free White Leghorn hens (GD – Animal Health, Deventer, the Netherlands) by inoculation via both an artificial and a natural route with a well-defined axenic T. gallinarum isolate obtained from one of the affected flocks. Other causes of granuloma disease were excluded.     

Generation of a velogenic Newcastle disease virus from cDNA and expression of the green fluorescent protein

Summary Newcastle disease virus (NDV) is a pathogen that is important in the poultry industry worldwide. Specifically, the virulent (velogenic) NDV is aparticular threat because it has now occurred frequently worldwide. The outbreaks caused by highly virulent NDV in waterfowl and especially in goose flocks, have led to greater concern in recent years as aquatic birds were previously resistant to most virulent NDV strains from chickens. The molecular determinants of host tropism, virulence and emergence of NDV isolated from diseased goose flocks are poorly understood. In the present study, we rescued a highly virulent NDV isolated from a goose using the reverse genetics approach. Infectious virus was successfully generated by cotransfection of a full-length cDNA clone of the NDV strain ZJ1 with helper plasmids. The recombinant NDV was indistinguishable from the parental wild-type virus with respect to its growth kinetics in cell culture as well as its biological properties. A recombinant NDV expressing green fluorescent protein (GFP) was generated, and GFP was subsequently detected in cells and various organs from the infected chickens.     

The epidemiology of Newcastle disease in rural poultry: A review

Rural poultry are the dominant form of poultry kept in the developing world. They are a natural resource whose potential is not fully exploited for the welfare of rural populations. The most devastating disease of rural poultry is Newcastle disease (ND). ND is an epidemic disease in intensive poultry and is responsible for high economic losses. Its epidemiology in intensive poultry is well understood, but little has been published on its behaviour in village poultry populations. Some research has been carried out during the past few years and it now appears that rural poultry are receiving increasing support for research and development from many government and international funding agencies throughout the world. All strains of Newcastle disease virus (NDV) occur in rural poultry, but velogenic strains are reported to be more common. Serological surveys in conjunction with isolation studies have shown that velogenic NDV strains are endemic in rural poultry populations even in isolated villages and possibly in isolated flocks. Although NDV is endemic in village poultry, the clinical disease usually follows an epidemic pattern. ND outbreaks often occur once or twice a year at regular intervals affirming the endemicity of the virus, however, 'mini' outbreaks in individual flocks and sporadic cases in individual birds may occur. Epidemics usually occur at times of climatic stress, leading to seasonal occurrence. The spread of NDV within and between village poultry populations is relatively slow due to a low contact rate. The major mode of transmission appears to be by the faecal-oral route. The respiratory route may also play a role in flocks where close bird-to-bird associations exist. Other poultry species, wild and feral birds, wild animals, communal water reservoirs and domestic animals may play a role in transmission; however, their role has not been properly investigated. In non-immune, intensively reared poultry, introduction of a sufficient quantity of virulent NDV is sufficient to cause severe outbreaks, but in rural poultry epidemic disease depends upon a number of factors. These include NDV pathotype, age structure and immunity of the host population, breed susceptibility, concurrent disease and seasonal influences. Although ND is endemic in rural poultry, many aspects of the epidemiology and economics of ND have not been fully understood. Well-designed, longitudinal studies made within a socio-economic framework are required to improve our understanding of the main problems of rural poultry systems.     

Demonstration of antibodies to Turkey rhinotracheitis virus in serum from commercially reared flocks of chickens

Using both an ELISA and a serum neutralisation test, antibodies to turkey rhinotracheitis (TRT) virus were found in sera collected from commercial flocks of chickens after the initial appearance of TRT in turkeys in Britain in mid-1985 but not in chicken sera collected before that time. Good correlation was found between the results of the two assays and antibodies were found in chickens of all commercial types and of all ages, ranging from 31 days to 56 weeks. Apparently healthy flocks appeared to have been infected with the virus, as did flocks which had recovered from a variety of disease outbreaks including ones attributed to infectious bronchitis, and severe tracheitis as well as swollen head syndrome. The results presented here do not provide conclusive proof of an association between the presence of TRT antibodies in chicken sera and any particular disease condition and it appears that TRT virus can infect chickens without necessarily being responsible for clinical disease.     

Cutaneous mucormycosis and diabetes: about one observation

Mucormycosis is a rare opportunistic infection but a fulminant disease. Varying clinical forms have been described, including cutaneous localisations which are mainly observed in diabetic and burned patients. The cutaneous lesions induced by the mucormycosis affection are often atypical and gangrenous. We report a case of cutaneous mucormycosis in a Tunisian patient with diabetic ketoacidosis. He developed cutaneous necrotic lesions at the low limb. The diagnosis of mucormycosis was not initially evoked but tardily confirmed by identifying mucorale hyphae in tissue sections and Rhizopus oryzae in the sample culture. The treatment consisted of an extensive surgical debridement associated with intravenous perfusion of amphotericin B. The patient had a fatal outcome.     

Occurrence of infectious laryngotracheitis outbreaks in commercial layer hens detected by ELISA

Infectious laryngotracheitis (ILT) is an acute respiratory disease of chickens and a cause of great economic loss in commercial layers. The aims of this study were to investigate the prevalence of ILT in the field outbreaks and to compare the characteristics of ILT-infected and free flocks of commercial layers. A total of 625 blood serum samples were collected from 25 different layer flocks. The presence of antibodies against infectious laryngotracheitis virus (ILTV) in each sample was determined by ELISA. Of the 625 serum samples, 266 (42.56%) were found to be positive for ILTV antibodies. A total of 16 (64%) flocks were detected ILT positive by ELISA method. The mortality of infected flocks was statistically higher (P < 0.05) than uninfected flocks. The egg production of positive flocks was lower than that of the free flocks, but this difference was not statistically significant. The average live weight of hens in infected flocks was lower (P > 0.05) than hens in free flocks. In conclusion, the results of this study indicated a high prevalence of ILT infection in the commercial layer flocks in Konya region, Turkey. In outbreaks, ILT significantly increased the mortality rate and decreased the average live weight in layer hens.     

Enterococcus cecorum infections in broiler breeders and their offspring: molecular epidemiology

Increased mortality and problems with lameness were reported in Dutch broiler flocks from the year 2008 onwards. Therefore, a field inventory, including 10 affected broiler flocks, nine corresponding broiler breeder flocks and five hatcheries, was carried out. The onset of clinical signs (lameness and increased mortality) started at about 2 weeks of age. The flock mortality varied from 3.1 to 8.1% at slaughter. Post-mortem lesions of broiler flocks were characterized by the occurrence of pericarditis/hydropericardium, arthritis and femoral head necrosis. Enterococcus cecorum was isolated from approximately 30% of the lesions. In the broiler breeders, E. cecorum was not isolated from any of the lesions. However, it was isolated from 31 out of 65 (47%) cloacal swabs, from two out of 65 (3%) oviduct samples, from one out 65 (1.5%) bone marrow samples and from two out of 25 (8%) blood samples. E. cecorum was not isolated from the air samples or dead-in-shell originating from the hatcheries involved. In total, 78 isolates were subjected to further typing by means of tRNA intergenic spacer PCR and confirmed as E. cecorum. The genetic relatedness of these cocci was subsequently studied using pulsed-field gel electrophoresis. The banding patterns of approximately 68% of E. cecorum isolates originating from parent stock flocks were clonal to one or more isolates of the same or other parent flocks. In contrast, isolates originating from their diseased offspring showed much greater genetic variation. Therefore, the vertical transmission of E. cecorum could not be demonstrated.     

Entzündliche Dermatosen Eine Auswahl klinisch wichtiger Krankheitsbilder

In the following a short overview on inflammatory dermatoses which are frequently diagnosed in clinical dermatology is presented. These include allergic contact dermatitis, dyshidrotic dermatitis, nummular dermatitis, seborrheic dermatitis, atopic dermatitis, lichen planus and psoriasis. Special emphasis is laid on the evolutionary stages in the development of lesions, clinically as well as histologically. The abovementioned dermatoses have a special pathological reaction pattern in common: the epidermis, papillary dermis and superficial capillary-venular plexus react together in these conditions and have therefore been termed the superficial cutaneous reactive unit.     

Effect of litter quality on foot pad dermatitis,hock burns and breast blisters in broiler breeders during the production period

Foot pad dermatitis and hock burn lesions are a form of contact dermatitis, a condition affecting skin areas in contact with unsuitable or irritating material. Contact dermatitis is a common problem, reducing the welfare of broilers, and is believed to also affect broiler breeders. However, there is very little research on contact dermatitis in breeders. This study followed the severity of foot pad lesions in broiler breeders throughout the production period. At slaughter the presence of hock burns and breast blisters was also determined. In addition, changes in litter condition over time and the impact of litter quality on foot pads were evaluated. The study was performed on 10 broiler breeder farms, including altogether 18 flocks. Foot pads of 100 hens per flock were assessed at the end of rearing period, three times during the production period, and at slaughter. Foot pad and hock lesions, as well as litter condition were scored on a 5-point scale. Litter quality was evaluated as pH, moisture and ammonia content. The condition of foot pads deteriorated towards slaughter age, with the occurrence of severe lesions reaching a maximum of 64% on average at slaughter. Hock lesions and breast blisters were rare. The litter layer became drier over time. Although poorer litter condition and wetness influenced foot pad health negatively, the effect on severe lesions was not significant. We also observed a negative effect on foot pad condition of larger slat areas. In conclusion, maintaining good litter quality alone is not enough to ensure healthy foot pads in broiler breeders.     

Molecular epidemiology of unilateral amyloid arthropathy in broiler breeders associated with Enterococcus faecalis

Although symmetrical polyarticular amyloidosis has been described extensively in brown layers, spontaneous unilateral amyloid arthropathy has not been described previously in chickens. Birds from nine flocks of broiler parent stock (PS) had unilateral lameness associated with severe swelling of the left hock joint and the caudal aspect of the metatarsus. Gross pathology was restricted to the left hock joint and the left digital flexor tendons in almost all cases, suggesting an association with administration of Marek's disease vaccine. Amyloid deposits were found in 83% (25/30) of affected joints by histological examination of Congo red stained sections. Systemic amyloidosis, involving mainly the liver and spleen, was found in 59% (10/17) of birds. Enterococcus faecalis was isolated from joints in 77% (23/30) of cases and Staphylococcus aureus was isolated from the joint in one case (1/30). Thirty-five E. faecalis isolates from joints, tendons and blood samples from birds in five affected PS flocks were compared using pulsed-field gel electrophoresis (PFGE) to separate genomic fragments after digestion with Sma I. All but one isolate had identical or closely related restriction endonuclease digestion (RED) patterns that were very similar to a known arthropathic and amyloidogenic E. faecalis isolate. A further 30 E. faecalis isolates from seven grandparent stock (GPS) flocks and two isolates from two unaffected PS flocks of the same genetic background were analysed by PFGE. Among these isolates, 11 originating from four GPS flocks had RED patterns identical to or closely related to the reference amyloid-inducing strain. Moreover, one E. faecalis isolate from amyloidotic joints of brown layers housed in California, USA was included in the analysis and appeared to be identical to the reference strain. This study showed that the E. faecalis isolates involved in these outbreaks of unilateral amyloid arthropathy in broiler breeders belonged to the same clone as that responsible for outbreaks in brown layers.     

A leukosis in turkeys associated with infection with reticuloendotheliosis virus

The clinical features and lesions are described for an outbreak of a leukosis in an integrated turkey breeding organisation. Turkeys had diarrhoea between 8 and 12 weeks of age and from 15 weeks onwards leukosis lesions appeared. A greater than 20% mortality occurred in most affected flocks. The disease was characterised clinically by enlargement of the liver and to a lesser degree other organs. Microscopically the lesions consisted of proliferations of lymphoblastoid cells. Reticuloendotheliosis virus (REV) was isolated from ailing culled turkeys and from cell cultures prepared from embryonated eggs produced by a flock with this disease. In affected flocks a REV was also isolated from turkeys 8 to 12 weeks of age in which enteritis was the main clinical feature. Inoculation of 1-day-old turkeys with this isolate of REV produced a syndrome of enteritis followed by leukosis. Antibody to REV was detected in turkeys surviving experimental inoculation and in the two flocks of turkeys examined, one of which had experienced considerable leukosis mortality.