Avian Pathology

Marek’s disease is a lymphoproliferative disease causing a serious threat in poultry production.
Field strains of Marek’s disease virus (MDVs) are continuously re-emerging, causing great
economical losses to the poultry industry worldwide in spite of the intensive vaccination and
restrictive management policy used. Histopathological and molecular characterizations of
MDVs are essential for monitoring the changes of viruses and evaluating the effectiveness of
existing vaccines. During 2016, 190 visceral tumour tissues representing 30 vaccinated
chicken flocks from the Gifu prefecture, Japan, were analysed. A pathological examination
revealed the presence of lymphoproliferative lesions in the visceral organs. Polymerase chain
reaction screening of tissue specimens using specific primers for avian leucosis virus,
reticuloendotheliosis virus, and MDV was positive only for MDV. The polymerase chain
reaction products of meq, pp38, virus-induced IL-8 homology, and glycoprotein MDV genes
were sequenced and used for homology, phylogenetic, and similarity level analysis with the
published reference of MDVs in the database. The results revealed high similarity between
the field isolates, vv and vv+ strains of MDV from the USA and China. Several point
mutations in the nucleotide sequence of the field isolates and their deduced amino acid
sequences were detected in those genes. The present molecular analyses indicated that
nucleotide and amino acid changes could be valuable criteria for differentiation and
determination of the pathogenicity and oncogenicity of MDVs according to the Avian
Disease and Oncology Laboratory pathotyping in vivo studies. Furthermore, the results
suggest that development of a new vaccine must be considered to overcome this
devastating avian oncogenic viral disease.

Fowl adenoviruses (FAdVs) cause disease in domestic chickens, including inclusion body hepatitis (IBH), with immunosuppression believed to play a role in their pathogenesis. To gain a better understanding of the pathogenesis and chronology of disease caused by FAdVs, the gross pathology, histopathology and dissemination of virus were examined in several different time points, after inoculation of one-day-old specific-pathogen-free chickens with FAdV-1, FAdV-8b or FAdV-11 via the ocular route. FAdV-8b had slightly greater virulence than FAdV-11, but both were primary pathogens. The presence and severity of hepatic lesions were used to define the three stages of the disease: incubation (1-3 days post-inoculation), degeneration (4-7 days post-inoculation) and convalescence (14 days post-inoculation). Both viruses were detected in the liver, kidney, bursa, thymus and gizzard of most birds during the degenerative stage, and persisted in the gizzard into convalescence. The FAdV-1 isolate ...

Normal egg formation is a reliable indicator of a bird’s health status. This study reports on egg
peritonitis in a 400 capacity, 54-week-old battery caged egg type chicken presented with soft
massive palpable abdomen. Abdominocenthesis using flexible rubber catheter revealed yolk in
the abdominal cavity. Abdomino-pelvis ultrasound scan revealed hyperechogenic regions of
soft shell eggs with pockets of anechogenic fluid filled areas while Ventra-dorsal X-ray
showed marked soft tissue inflammation of pectoro-abdominal region. Escherichia coli were
isolated from the abdominal aspirate at Microbiology laboratory. Surgical intervention was
employed to correct the condition. This study showed possible surgical approach to correcting
egg peritonitis in birds and also suggested other possible intervention ways to help farmers
take timely management decisions.

Abstract
Bacterial pathogens affecting birds are numerous. This paper covers many of the species that affect companion birds and the antibiotics most commonly used to deal with them. Beneficial and harmful bacteria are discussed as well as the harmful effects of bacterial infections. Diagnostic testing with staining, cultures, histopathology, and cytology and explained.

The effects of the Saccharomyces cerevisiae (SC) and Fructooligosaccharide (FOS) on body weight, feed conversion, body weight gain and immune response was investigated in broiler fed on aflatoxin (AF). A total number of 180 one day old broiler chickens (Hubbard classic) were randomly distributed into 6 experimental groups; G1: control (basal diet), G2: (basal diet + SC 2%), G3: (basal diet + FOS 0.25%), G4: (basal diet + AF100μg), G5: (basal diet + AF100μg + SC 2%), G6: (basal diet + AF100μg + FOS 0.25). The weight range, feed conversion, body weight gain and humoral immunity of birds were evaluated. Results of (G2) and (G3) show a significant (P<0.05) increase weight range, body weight gain, fed conversion ratio and the antibody titers in compare to control, while the AF contaminated diet (G4) showed decrease in body weight gain, feed conversion ratio and the antibody titers against Newcastle disease virus. Aflatoxin groups treated with 2% Saccharomyces cerevisiae (G5) and 0.25% fructooligosaccharide (G6) show increased in the broilers performance value and humoral immune response of broilers vaccinated against Newcastle virus disease as compared to the aflatoxin group (G4). In conclusion the addition of Saccharomyces cerevisiae and fructooligosaccharide had a beneficial effects on broilers health and can minimize the effect of aflatoxin on broiler performance and immunity.

Infectious bursal disease virus (IBDV) is the aetiological agent of the acute and highly contagious infectious bursal disease (IBD) or “Gumboro disease”. IBD is one of the economically most important diseases that affects commercially produced chickens worldwide. Along with strict hygiene management of poultry farms, vaccination programmes with inactivated and live attenuated viruses have been used to prevent IBD. Live vaccines show a different degree of attenuation; many of them may cause bursal atrophy and thus immunosuppression with poor immune response to vaccination against other pathogens and an increase in vulnerability to various types of infections as possible consequences. Depending on their intrinsic characteristics or on the vaccination procedures, some of the vaccines may not induce full protection against the very virulent IBDV strains and antigenic variants observed in the last three decades. As chickens are most susceptible to IBDV in their first weeks of life, active immunity to the virus has to be induced early after hatching. However, maternally derived IBDV-specific antibodies may interfere with early vaccination with live vaccines. Thus new technologies and second-generation vaccines including rationally designed and subunit vaccines have been developed. Recently, live viral vector vaccines have been licensed in several countries and are reaching the market. Here, the current status of IBD vaccines is discussed.

The immune responses of indigenous naked neck (NaNa and Nana) and normally feathered (nana) chickens against a Salmonella Gallinarum (SG) infection were evaluated and compared withth ose of a commercial line (B-380). Groups of 28-day-old chickens (NaNa, Nana, nana, and B-380) were immunized orally and subcutaneously with 50 μg of SG antigens. Control non-immunized animals were inoculated withsterile saline solution. All chickens were challenged with 1 LD50 of SG and mortality was recorded daily for 20 days. Antibodies to SG were measured in sera before immunization, before the challenge, 10 days after the challenge, and at sacrifice. Peripheral blood lymphocyte proliferation assays were performed using concanavalin A and SG antigens. Results showed that non-immunized Nana chickens exhibited the best natural resistance to Salmonella infection, since only 30% of them died. In contrast, all control B-380 chickens died by the 13th day. Immunization with SG induced immunity in chickens of all genotypes. Indigenous naked neck and normally feathered chickens showed a higher survival rate when compared with B-380 chickens. Immunized Nana chickens showed the highest antibody titres (P < 0.05) as well as the highest thymidine incorporation in peripheral blood lymphocytes stimulated with con A or SG antigens (P < 0.05). The results show that Nana chickens are the most resistant to SG infection and the best responders to vaccination with SG antigens.

This study investigated the immune responses to La Sota vaccination, used in protection of chickens against Newcastle disease, in light weight type breeds of chickens (pullets) and heavy weight type breeds of chickens (broilers) used in commercial poultry
production. Seven-week-old 50 White Marshall broilers (Br) and 50 Isa Brown pullets (Pu) were randomly divided into four groups: vaccinated broilers chickens;
(VBr), unvaccinated broiler chickens (UBr), and vaccinated pullet chickens (VPu) and unvaccinated pullet chickens (UPu). Chickens in groups VBr and VPu were vaccinated with La Sota vaccine, whereas groups UBr and UPu were not vaccinated. On day 0 post vaccination (PV), six chickens from group Br and Pu, and on day 4 PV, three chickens from each four groups were sacrificed and the bursa weight index (BWI), thymus weight index (TWI) and the splenic weight index (SWI) were obtained. The chickens were observed for clinical signs and lesions. Serum samples were collected
from the chickens in all the groups on days 0, 7, 14, 21, 28 PV and assayed for haemagglutination inhibition (HI) antibodies. The BWI, TWI and SWI were 0.37 ± 0.05, 0.35 ± 0.17, 0.65 ± 0.26 for pullets and 0.11 ± 0.04, 0.13 ± 0.02, 0.36 ± 0.17 for broilers on day 0 PV. On day 4 PV there was no significant difference (p < .05) between the indices of the vaccinated and unvaccinated chickens. The geometrical mean antibody titres (GMT) of the pullets were 2 to 3 times higher than those of the broilers on days 7 to 28 PV. Vaccination did not produce clinical signs or lesions. The above observations show that naturally pullets produce higher antibodies than broilers because of their higher BWI.

Avian reovirus (ARV) is an important pathogen of poultry and causes significant economic losses to the poultry industry. To develop a rapid and sensitive method for the surveillance of ARV, a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was established using a set of six primers specific to the S1 gene segment of ARV. The established assay was performed at 62oC for 60 min in a thermal block, and the result was visualized directly under daylight or ultraviolet light. The detection limit of the RT-LAMP assay was 10 fg total RNA, which was 100-fold higher than that of reverse transcriptase polymerase chain reactions. The specificity of the assay was supported by the lack of cross-reaction with other avian pathogens. Furthermore, viral RNAs of field isolates were successfully detected by the assay. Overall, the newly established RT-LAMP assay is simple, rapid, sensitive, specific, and can visually detect ARV without the use of any specialized equipment.

Early cases of colibacillosis with omphalitis, yolk sac infection and increased mortality were observed in five broiler chicken flocks (A1, A2, A3, A4 and B1) from two broiler breeder flocks A and B, respectively. Avian pathogenic Escherichia Coli (APEC) serotype O78, Fim/Tsh/Iuc pathotype, were isolated from flocks A, A1, A2, A3 and A4, and APEC serotype O139, pathotype Fim/Iuc, from flocks B and B1. APEC O78 strains isolated from broiler chicks A1, A2, A3 and A4, originating from breeder flock A, had the same antibiotic resistance pattern as APEC O139 strains isolated from broiler chicks B1 and breeder B.The random amplified polymorphic DNA technique performed on APEC strains revealed two distinct clusters of genetic similarity: cluster I consisted of some APEC O78 and cluster II of APEC O139. These results indicated that a transmission of APEC strains from adults A and B to their respective progeny could occur.Transmission d' Escherichia coli pathogène aviaire (APEC) à partir de reproducteurs de type chair à leur descendance dans une production intégrée.Les cas précoces de colibacillose avec omphalite, infection du sac vitellin, et augmentation de mortalité, ont été observés dans cinq troupeaux de poulets de chair A1, A2, A3, A4 et B1 issus de deux troupeaux de reproducteurs respectivement A et B. Des Escherichia coli pathogènes aviaires (APEC) sérotype O78, pathotype Fim/Tsh/Iuc ont été isolés des troupeaux A1, A2, A3, A4 et des APEC O139, pathotype Fim/Iuc ont été isolés des troupeaux B et B1. Les souches d'APEC O78 isolées à partir des poulets de chair A1, A2, A3 et A4 issus du troupeau de reproducteurs A, avaient le même profil de résistance aux antibiotiques que les souches de l'APEC O139 isolés des poulets de chair B1 et des reproducteurs B.Les souches d'APEC ont fait l'objet d'une analyse par RAPD qui a révélé que ces souches se répartissaient en deux groupes distincts de similarité génétique : le groupe I comprenant quelques APEC O78, et le groupe II comprenant les APEC O139. Ces résultats ont montré que la transmission des souches d'APEC des adultes A et B à leur descendance respective peut se produire.Übertragung von Escherchia coli (APEC) von Broilerelterntieren auf ihre Nachkommen innerhalb einer integrierten GeflügelproduktionsketteIn fünf Broilerherden (A1, A2, A3, A4 und B1) von zwei Broilerelterntierherden (A und B) wurden frühe Fälle von Colibazillose verbunden mit Omphalitis, Dottersackinfektion und erhöhter Mortalität beobachtet. Aus den Herden A, A1, A2, A3 und A4 wurden pathogene aviäre Escherichia coli (APEC)-Serotyp O78,-Pathotyp Fim/Tsh/iuc und aus den Herden B und B1 APEC-Serotyp O139, -PathotypFim/Iuc isoliert. Die O78-APEC-Stämme aus den Broilerherden A1, A2, A3 und A4, die von der Broilerelterntierherde A abstammten, wiesen das gleiche Antibiotikaresistenzmuster auf wie die O139-APEC-Stämme aus den Broilern aus Herde B1 und ihrer Elterntierherde B. Die mit den APEC-Stämmen durchgeführte RAPD-Technik ließ zwei verschiedene genetische Cluster erkennen: Cluster I beinhaltete einige der APEC O78- Stämme und Cluster II die APEC O139. Diese Ergebnisse weisen darauf hin, dass eine Übertragung von APEC-Stämmen von den Adulten der Herden A und B auf ihre Nachkommen vorkommen kann.Transmisión de Escherichia coli patógena aviar (APEC) de reproductores a su progenie en una cadena de producción avícola integradaSe observaron casos tempranos de colibacilosis con onfalitis, infección del saco vitelino y mortalidad incrementada en cinco lotes de pollos de engorde A1, A2, A3, A4 y B1 provenientes de dos lotes de reproductores, A y B respectivamente. Se aisló una Escherichia Coli patógena aviar (APEC) serotipo O78, patotipo Fim/Tsh/Iuc de los lotes A, A1, A2, A3, A4 y APEC del serotipo O139 y patotipo Fim/Iuc de los lotes B y B1. Las cepas APEC O78 aisladas de los pollitos A1, A2, A3 y A4, originarios de los lotes de reproductores A, presentaron el mismo patrón de resistencia a los antibióticos que las cepas APEC O139 aisladas de los pollitos de engorde B1 y de los reproductores B.La técnica de RAPD realizada sobre las cepas APEC reveló dos grupos distintos de similaridad genética: el grupo I consistió en algunas APEC O78 y el grupo II en APEC O139. Estos resultados indican que la transmisión de cepas APEC de adultos A y B a su progenie respectiva puede ocurrir.