Retrospective analysis of sero-prevalence and bait uptake estimations in foxes after oral rabies vaccination programmes at European level: Lessons learned and paths forward.

Rabies caused by the Classical Rabies Virus (Lyssavirus rabies abbreviated RABV) in the European Union has been close to elimination mainly thanks to Oral Rabies Vaccination (ORV) campaigns targeting wildlife (primarily red foxes). ORV programmes co-financed by the European Commission include a monitoring-component to assess the effectiveness of the ORV campaigns at national level. This assessment is performed by a random collection of red foxes in the vaccinated areas with control of antibodies presence by serological analysis and control of bait uptake by detection of biomarkers (tetracycline incorporated into the baits) in the bones and teeth. ORV programmes aim to a vaccine coverage high enough to immunize (ideally) 70 % of the reservoir population to control the spread of the disease. European Union (EU) programmes that led to almost elimination of rabies on the territory have been traditionally found to have a bait uptake average of 70 % (EU countries; 2010-2020 period) while the seroconversion data showed an average level of 40 % (EU countries; 2010-2020 period). To better understand variations of these indicators, a study was been set up to evaluate the impact of several variables (linked to the vaccination programme itself and linked to environmental conditions) on the bait uptake and the seroconversion rate. Thus, pooling data from several countries provides more powerful statistics and the highest probability of detecting trends. Results of this study advocate the use of a single serological test across the EU since data variation due to the type of test used was higher than variations due to field factors, making the interpretation of monitoring results at EU level challenging. In addition, the results indicates a negative correlation between bait uptake and maximum temperatures reached during ORV campaigns questioning the potential impact of climatic change and associated increase of temperatures on the ORV programmes efficiency. Several hypotheses requesting additional investigation are drawn and discussed in this paper.

First Detection and Identification of FAdV-8b as the Causative Agent of an Outbreak of Inclusion Body Hepatitis in a Commercial Broiler Farm in Greece.

Inclusion body hepatitis (IBH) is an economically important disease of chickens, with a worldwide distribution, caused by Fowl Aviadenoviruses (FAdVs). Currently, the increased number of cases, the virulence of the isolate strains, as well as the lack of cross-species protection highlight that detailed in-field data are fundamental for the development of successful control strategies. This case report provides a detailed clinicopathological investigation of an unusual IBH outbreak in a commercial broiler farm in the region of Macedonia, Greece. The farm consisted of 64,000 birds, originated from the same breeder stock and placed in three different houses (Flock A-C). At 20 days of age, a sudden increase in daily mortality was recorded in Flock A. It is worth mentioning that, although all flocks were serologically (indirect ELISA) and molecularly (RT-PCR) positive for FAdV, the mortality rate, attributed to IBH, was much higher in Flock A compared to others. The clinical manifestation included non-specific symptoms such as depression, inappetence, yellowish mucoid diarrhea, and lack of uniformity. At necropsy, typically, enlarged, pale, and friable livers were dominant, while sporadically lesions were recorded in the pancreas, kidneys, skeletal muscles, and lymphoid organs. The histopathological examination of liver samples showed multifocal inflammation, necrosis, and the presence of basophilic/ eosinophilic inclusion bodies in hepatocytes. In addition, the loss of the architecture of pancreatic lobules and the presence of fibrosis and foci of mononuclear cell aggregates were suggestive of chronic pancreatic inflammation. PCR analysis confirmed the presence of FAdV, belonging to species E, serotype FAdV-8b. Performance and financial calculations revealed that IBH increased Feed Conversion Ratio (FCR), feed cost/chick as well as feed cost/kg live weight, whereas the Livability (%) and the European Production Efficiency Factor (EPEF) were decreased in the most severely affected flocks (Flock A). This study is the first report of the detection and identification of FAdV serotypes associated with IBH in commercial broiler flocks in Greece. However, there is still a lack of information about the circulating FAdV serotypes in the country, and therefore epidemiological studies are needed to establish control strategies for IBH.

Investigation of a Novel Multicomponent Mycotoxin Detoxifying Agent in Amelioration of Mycotoxicosis Induced by Aflatoxin-B1 and Ochratoxin A in Broiler Chicks.

The present study was designed to determine the efficacy of a novel multicomponent mycotoxin detoxifying agent (MMDA) containing modified zeolite (Clinoptilolite), Bacillus subtilis, B. licheniformis, Saccharomyces cerevisiae cell walls and silymarin against the deleterious effects of Aflatoxin B1 (AFB1) and Ochratoxin A (OTA) in broiler chicks. A total of 160 one-day-old Ross 308® broiler chicks were randomly allocated in four treatment groups, with four replicates, according to the following experimental design for 42 days. Group A received a basal diet; Group B received a basal diet contaminated with AFB1 and OTA at 0.1 mg/kg and 1 mg/kg, respectively; Group C received a basal diet contaminated with AFB1 and OTA and MMDA at 1 g/kg feed, and Group D received a basal diet contaminated with AFB1 and OTA and MMDA at 3 g/kg feed. Results showed that ingested mycotoxins led to significant (p ≤ 0.05) reduction in body weight and feed conversion from 25 days of age, induced histopathological changes, increased the pH of the intestinal content, and altered the biochemical profile of birds with significantly (p ≤ 0.05) increased aspartate aminotransferase (AST) values (p ≤ 0.05). On the other hand, the supplementation of MMDA significantly (p ≤ 0.05) improved the feed conversion ratio (FCR) during the second part of the study, diminished biochemical alterations, reduced pH in jejunal and ileal content, and E. coli counts in the caeca of birds (p ≤ 0.05). It may be concluded that the dietary supplementation of the MMDA partially ameliorated the adverse effects of AFB1 and OTA in broilers and could be an efficient tool in a mycotoxin control program.

Efficacy of a Dietary Polyherbal Formula on the Performance and Gut Health in Broiler Chicks after Experimental Infection with Eimeria spp.

One-hundred and fifty, one-day-old Ross-308 female chicks were randomly allocated to five equal treatments: NCONTR negative control-not challenged; PCONTR positive control-challenged; PHERB1 and PHERB2 diets were supplemented with phytogenic formula (1 and 2 g/kg feed, respectively)-challenged; PSALIN diet was supplemented with salinomycin (60 mg/kg feed)-challenged. Challenge was made by oral inoculation with 3.5 × 104 E. acervulina, 7.0 × 103 E. maxima and 5.0 × 103 E. tenella oocysts, at 14 days of age. One week post inoculation, bloody diarrhea, oocysts numbers, and intestinal lesions were evaluated, along with intestinal microbiota, viscosity, and pH of digesta, and histopathology. PHERB2 had a comparable (p ≤ 0.001) growth performance and feed conversion ratio to PSALIN. PHERB1 and PHERB2 had similar (p ≤ 0.001) oocyst counts to PSALIN and lower than PCONTROL. PHERB2 and PSALIN had lower (p ≤ 0.001) jejunal, ileal, and cecal lesion scores compared to PCONTR. PHERB1 and PHERB2 had higher (p ≤ 0.001) jejunal and cecal lactobacilli and lower (p ≤ 0.001) coliform counts compared to other treatments. PCONTR had lower (p ≤ 0.001) jejunum villus height, height to crypt ratio, and villus goblet cells. Breast and thigh meat resistance to oxidation was improved (p ≤ 0.001) in PHERB1 and PHERB2 compared to the PCONTR. The polyherbal formula exerted a substantial improvement on growth performance and intestinal health of the Eimeria-challenged birds.

A Case of Infectious Laryngotracheitis in an Organic Broiler Chicken Farm in Greece.

Infectious laryngotracheitis is an economically significant viral disease of chickens, that mainly affects the upper respiratory tract, and is present worldwide. This case reports the first outbreak of infectious laryngotracheitis in a four-week-old organic broiler farm and surrounding flocks in Greece, with typical clinical symptoms and lesions, allegedly provoked by a wild strain of infectious laryngotracheitis virus. Our findings contradict the general perception indicating that the disease appears mainly in older birds and that vaccine strains are the primary cause of infectious laryngotracheitis outbreaks in most continents. A recombinant vectored vaccine was administered, supplementary to biosecurity measures, containing the viral spread. The responsible strain was potentially circulating in the area; therefore, an industry-wide holistic approach was applied, including the vaccination of neighboring broilers and breeders with the same vaccine, the rapid molecular diagnosis of the disease, and strict biosecurity protocols. The results of this holistic effort were effective because, following the application of vaccine and management protocols, manifestations of the disease in regional flocks dropped significantly, and there was no recurrence to date. These findings suggest that vaccination protocols should be modified, especially for organic broilers, to include vaccination against infectious laryngotracheitis.

Avian Mycobacteriosis and Molecular Identification of Mycobacterium avium Subsp. avium in Racing Pigeons (Columba livia domestica) in Greece.

In this report, cases of avian mycobacteriosis in two lofts of racing pigeons are described. Three racing pigeons of 2-year old from the first loft (A) and four racing pigeons of 4-5 years old from the second loft (B) were submitted to the Unit of Avian Medicine for clinical examination and necropsy. In the case history chronic and debilitating disease was reported. The clinical signs included emaciation, depression, lameness, periorbital swelling and diarrhea, although the appetite was normal. Post mortem lesions involved an enlarged spleen with multiple different sized yellow nodules. Similar lesions were also observed in the liver, conjunctiva of the inferior eyelids and in the femoral bone marrow. The suspicion of avian mycobacteriosis was based on history, clinical signs and typical lesions. In order to confirm the diagnosis, histopathology was performed on tissue sections and revealed the presence of multiple granulomas with central necrosis. In addition, Ziehl-Neelsen positive bacilli were observed in histological sections and smears from the granulomas of the affected tissues. Molecular analysis identified the causative agent as Mycobacterium avium subsp. avium. This is the first case report of avian mycobacteriosis in Greece, which describes the presence of granulomatous conjunctivitis and the molecular identification of M. avium subsp. avium as the causative agent in racing pigeons.

The Effect of Whey on Performance, Gut Health and Bone Morphology Parameters in Broiler Chicks.

Whey is a highly nutritious byproduct of the cheese industry that can be used effectively in the animal feed industry. However, the use of whey in poultry diets is limited by its high lactose and mineral contents. The objective of the present study was to evaluate the effect of different concentrations of whey in poultry diets on the performance, intestinal microbiota and physico-chemical parameters of the intestinal ecosystem, as well as on the bone morphology and its strength in broiler chicks. One hundred and twenty-eight, day-old, male broiler chicks were randomly allocated into four treatment groups of 32 chicks each. The treatment groups were: group A, which served as negative control and groups B, C and D, supplemented with 1, 2 and 5% of dietary whey, respectively. Performance of the groups was evaluated throughout the experiment. Following necropsies, the gastrointestinal tract from each bird was removed, divided into its anatomical parts and intestinal samples were taken for microbiological analysis and for pH and viscosity measurement as well. Tibiotarsus was also collected for morphometric analysis and strength evaluation. The statistical analysis of the experimental data revealed that the dietary supplementation of 1 and 2% of whey improved significantly (p ≤ 0.05) the body weight, while the addition of 5% of whey reduced significantly (p ≤ 0.05) the body weight. Furthermore, the addition of 1, 2 and 5% of dietary whey increased significantly (p ≤ 0.05) the pH of jejunum digesta and reduced significantly (p ≤ 0.05) the pH of caecum digesta compared to the control group. The addition of 1 and 2% of whey reduced significantly (p ≤ 0.05) the viscosity in the jejunum and ileum digesta, compared to the addition of 5% of whey which reduced significantly (p ≤ 0.05) the viscosity in jejunum digesta but increased significantly (p ≤ 0.05) the viscosity in ileum digesta. Moreover, the addition of 1, 2 and 5% of dietary whey increased significantly (p ≤ 0.05) the caecal counts of Lactobacillus spp. and Lactococcus lactis, while the addition of 5% of whey reduced significantly (p ≤ 0.05) the tibiotarsus length. It can be concluded that the addition of low quantities of whey up to 2% promoted the performance and gut health of birds, while the addition of higher quantities of whey at the level of 5% had a detrimental effect on the performance and tibiotarsus length.

Dimethylglycine Supplementation in Reduced Energy Broilers' Diets Restores Performance by Improving Nutrient Digestibility.

Reducing the energy content of broiler diets could lead to the formulation of diets with reduced production cost. Dimethylgycine (DMG) has been used as a dietary supplement to enhance dietary fat utilization in poultry. The objective of the present study was to investigate the effects of DMG supplementation in reduced energy diets on performance and nutrient digestibility in broiler chickens. Four hundred and eighty day-old broilers were randomly allocated to three dietary treatments: a standard energy diet (PC treatment), a reduced energy diet by 66 kcal/kg (NC treatment) and the reduced energy diet supplemented with 500 mg/kg of DMG (DMG treatment). Fat digestibility was significantly higher in DMG group, compared to PC and NC groups. Intestines and gizzard lesion scores were found to be lower in the DMG group compared to PC. DMG supplementation resulted in lower jejunum pH and ileum viscosity in broilers. Overall, the present study showed that DMG supplementation in reduced energy broiler diets restored growth performance to the levels obtained with a standard diet. This result was probably mediated by the positive effects on the gastrointestinal function of the broilers after DMG supplementation, as evidenced by the improved nutrient digestibility, the reduced gross lesion scores and the lower values in intestinal pH and viscosity.

Antibody Response Following Pre-Exposure Immunization Against Rabies in High-Risk Professionals.

Vaccination against rabies and routine antibody testing of subjects participating in programs for the surveillance and control of rabies in animals is strongly recommended. The scope of this study is to describe the antibody level as measured by a commercial enzyme-linked immunosorbent assay (ELISA) after primary and booster intramuscular vaccination with a purified vero-cell rabies vaccine (PVRV) in high-risk professionals and to determine the influence of an array of factors on antibody level, that is, time elapsed since primary immunization series and booster dose, sex, age, pathologic conditions, high-risk occupation, and peak antibody level after initial scheme and booster dose. A primary series of three doses of PVRV was administered and a commercial ELISA was recommended 14 days postimmunization with continuous repetition at 6 months and yearly intervals for the laboratory personnel and the rest of the professionals, respectively. The protective antibody titer was defined as a minimum of 0.5 equivalent units/mL (EU/mL) (seroconvertion) and a booster dose was applied if the titer was determined nonprotective. The seroconversion rate (SCR) after primary vaccination was 100%, with a geometric mean titer (GMT) of 2.90 EU/mL (interquartile range [IQR]: 1.85-3.45). After booster vaccination due to nonprotective titer, the SCR was 100% and the GMT increased by 678% (95% confidence interval [CI]: 514-887) reaching 4.25 EU/mL (IQR: 4.00-4.60), 2.5 times higher than the GMT elicited by the primary vaccine scheme in the respective recipients. The titer dropped by 1.20% per month (95% CI: 0.52-1.89) regardless of booster administration or any other factor. Women had 51% higher titer compared with men (95% CI: 6-116). High-risk professionals should be verified for adequate antibody titers, but routine administration of a single booster dose of PVRV 1 year after the primary series could be considered; more evidence is needed to support the benefit in terms of immunity and logistics.

The potential role of migratory birds in the transmission of zoonoses.

The instinct for survival leads migratory birds to exploit seasonal opportunities for breeding habitats and food supplies. Consequently, they travel across national and international borders. These birds are distinguished in local migrants, short-distance, long-distance and vagrant and nomadic migrants. They can transfer micro-organisms across the globe and play a significant role in the ecology and circulation of pathogenic organisms. They are implicated in the transmission of zoonoses as biological and mechanical carriers and as hosts and carriers of infected ectoparasites. They can cause water-borne, tick-borne and insect-borne diseases. Favourable agents, such as seasonality and stress due to migration, influence the transmission of pathogens. The migration of birds is a natural phenomenon that is followed by the unavoidable repercussions of the participation of these birds as carriers or hosts in the transmission of pathogens. It is not possible to interrupt this sequence but risks can be minimised by controlling and preventing perilous situations. Surveillance of wetlands, 'stopovers', places of destination and wintering regions can be done. Furthermore, the implementation strict biosecurity measures that reduce contact with migratory birds will limit the transmission of pathogens.

Rupture of the right auricle in broiler chickens.

This report describes a case of cardiac right auricle rupture (RAR) in a flock of 11,500 broilers that were 14 days old. The birds were housed at an altitude of 300 m, with an external temperature of -10 degrees C and an internal temperature of 15 degrees C. There was 3.6% mortality, due to sudden deaths, from 10 to 14 days of age. All necropsied birds had haemopericardium due to RAR at the point of the junction with the vena cava, and 85% of them had blood in the oral cavity and external acoustic meatus. The vena cava and its caudal branches, the intestinal vessels, and the sinus durae matris and sinus saggitalis were distended. Histological examination showed haemorrhages into the myocardium, degeneration of the cardiac muscle fibres, as well as oedema of the lungs and hypertrophy of the smooth muscle bundles of the parabronchial walls. Blood in the mouth of the broilers may have been due to haemoptysis, which in humans is caused mainly by mitral stenosis. In broilers, mitral stenosis and/or insufficiency, and left ventricular failure with consequent pulmonary hypertension (PH) were considered as possible triggers for right ventricular failure. The alarm reaction in hypoxaemia, due to secondary factors such as cold, caused tachycardia and tachypnoea, may have induced further elevation of PH, and acute myocardial infarction causing cardiac rupture and haemopericardium in this case. Hypertension and PH, due to possible mitral stenosis/insufficiency in association with acute myocardial ischaemia, were probably the determinant factors causing this acute episode. This opens the possibility that the RAR may be cardiogenic.