Inclusion body hepatitis in a flock of commercial broiler chickens

Thirty- four-day-old broilers from a flock of chickens in a commercial farm in Perak with history of poor growth and high mortality were submitted for necropsy. On necropsy, mild to moderate enlargement of liver with pale, friable and fatty changes in appearance, and areas of haemorrhage and congestion were observed. The kidney was pale and slightly enlarged. Histologically, numerous eosinophilic and basophilic, round or irregular-shaped intranuclear inclusion bodies were observed in the hepatocytes. The hepatic parenchyma was moderately degenerated and necrotised. Moderate congestion with areas of haemorrhage and moderate to severe infiltration of mononuclear inflammatory cells were also observed in the liver

Pathogenecity of Salmonella enteritidis phage type 1 isolate of Malaysia in 21 day old specific pathogen free chicken

Salmonella enteritidis (SE) has always been related to subclinical infection in the chickens infected after 2 weeks of hatching. However, few pathogenic phage types were proven for their ability to manifest systemic infection and cause the organism to be shed into the surrounding environment. It was the objective of the study to determine the pathogenicity of SE Phage Type (PT) 1 in Specific-Pathogen-Free (SPF) chickens. About 93, 21 day old SPF chickens where divided into 3 groups namely the Control, SE and Mortality groups. The chickens were raised separately in caging system and given free access to antibiotic-free ration and water. The SE and Mortality groups were inoculated orally (1.0 mL) with SE PT 1 (1x108 cfu mL-1). The chickens in the SE and Control groups were sacrificed at various intervals throughout the trial. Samples were collected for bacterial isolation and histological examination. The mortality percentage of the chickens in the Mortality group was recorded. The study showed that no mortality was recorded throughout the trial in the mortality as well as the SE group. Body weight was lower in the SE group when compared to the Control group throughout the trial except at days 2, 3 and 5 post inoculation (pi) reaching its peak at day 14 pi when the SE group body weight was 26% lower than the controls. Clinical signs observed in the SE and Mortality group were represented by diarrhoea, inappetance, ruffled feather and stunted chickens while no abnormal clinical signs where recorded in the Control group. Grossly mild airsacculitis, mild peritonitis and hepatic congestion where recorded in the SE group at day 2 pi until day 5 pi while no gross lesions where recorded in the Control group. SE was first isolated in the caecum (66%) at 12 h pi. At day 1 pi SE was isolated from the caecum and spleen (33%) whilst at day 2, SE was isolated from the caecum (100%) and caecal tonsil (66%). No SE was isolated from the cloacal swabs throughout the trial. The villi height was generally lower in the SE group when compared to the Controls, however it was significantly lower (p<0.05) in the duodenum at 12 h, days 1, 3, 5, 10, 14 and 21 pi; in the jejunum at 6 h, days 2, 14 and 21 pi while in the ileum at days 1, 3 and 5 pi. The crypts depth measurement was fluctuating however it ended up by being higher in the SE group, nevertheless it was significantly lower (p<0.05) in the SE group when compared to the Control group in the duodenum at 6 h and day 14 pi in the jejunum at day 10 pi; in the ileum at 12 h pi. Histopathological changes recorded included hepatitis, congestion and focal areas of necrosis; splenitis, congestion and oedema in the adenoid sheathed arteries; congestion and areas of necrosis in the lymphoi follicles of the bursa of Fabricius; enteritis, congestion and sloughing of necrotic enterocytes in the intestinal villi with presence of bacterial clusters in the villi surface and intestinal lumen. SE rods present in the caecal tonsils were seen to be engulfed by macrophages at days 1 and 2 pi, necrosis of the enterocytes on the villi surface and infiltration of the bacteria was recorded at day 2 pi while at days 5 pi the bacteria multiplication were seen and often located upon the M-like M cells however, no actual engulfment was recorded

Pathogenicity of avian pathogenic Echerichia coli isolates of Malaysia in specific pathogen free chickens

Avian pathogenic Escherichia coli (APEC) infections of poultry have been regarded to be a major infectious disease in birds and are economically important to poultry production worldwide. The infection is still widely believed to be opportunists or secondary to predisposing conditions. Current studies suggest that APEC is also potentially zoonotic. Existence of APEC in Malaysia is evident but its pathogenicity in poultry is still unknown. The objective of this study was to determine the pathogenicity of APEC of Malaysian isolates in specific pathogen free (SPF) chickens. Fifty-four, day-old SPF chicks were divided into three groups; A, B and C. Each group was further categorized into sacrificed and mortality subgroups. The chicks in sacrificed subgroup were used for sampling and those in the mortality subgroups were only observed for mortality with minimal handling. All chicks were fed an antibiotic-free diet and fresh water ad libitum throughout the study. Chicks in groups A and B were inoculated with 0.1 mL of 1 × 108 CFU APEC isolate A (UPM 1101) and APEC isolate B (UPM 1102), respectively whereby 0.05 mL 1 × 108 CFU each was given orally and intranasally. All chicks in group C were left uninoculated and served as controls. Three chicks were sacrificed prior to APEC inoculation. On days 1, 4, 7 and 14 post-inoculation (pi), three chicks each from the sacrificed subgroups of groups A, B and C were sacrificed. Body weights of the sacrificed chicks were recorded and cloacal swab, blood, and liver samples were taken for bacterial isolation and identification. The liver and trachea samples were also taken for histopathological examination. All chicks were observed for clinical signs and mortality throughout the trial. At necropsy, gross lesions were also examined. One dead chick (20%) was observed in mortality subgroup of group B. No mortality was recorded in mortality groups of groups A and C. Chicks in group A developed mild diarrhoea with faecal stains around cloacal area on day 4 pi, uneven body size distribution and ruffled feathers on day 14 pi. Chicks in group B showed moderate diarrhoea with faecal stains around cloacal area on day 4 pi, watery dark brownish diarrhoea, uneven body size distribution and ruffled feathers on day 14 pi. Chicks in group C remained healthy throughout the trial. There was no significant (p > 0.05) difference in mean body weight between the three groups. At necropsy, unabsorbed yolk was observed in all sacrificed chicks from groups A, B and C on day 1 pi. Unabsorbed yolk continued to be seen in chicks from group B on day 4 pi. Focal liver necrosis was observed in chicks from group A on day 7 pi. Histopathology revealed presence of lymphocytes and heterophils in submucosa of trachea of chicks from group B as early as day 1 pi and with mild deciliation on days 4, 7 and 14 pi. Lymphocytes and heterophils in submucosa of trachea were recorded in chicks from group C starting from day 4 pi. In group A, the presence of lymphocytes and heterophils in submucosa of trachea with mild deciliation was observed on days 4, 7 and 14 pi. Area of degeneration and necrosis of liver were also observed on day 7 pi. It was concluded that the A (UPM 1101) and B (UPM 1102) APEC isolates of Malaysia are mildly and moderately pathogenic, respectively in SPF chicks

Pathogenicity of the Malaysian Salmonella enteriditis phage type 6a isolate in specific pathogen free chickens.

Salmonella enteritidis (SE) remains an important cause of zoonotic diseases. Humans are commonly infected with SE from chickens through food borne origin. It is suspected that different phage types of SE could cause different severity of infections in chickens. It was the objective of this study to determine the pathogenicity of SE phage type 6a in specific pathogen free (SPF) chickens. Seventy-two, day-old SPF chicks were divided into three groups namely, SE, mortality and control groups. All chicks were fed with an antibiotic free diet and fresh water ad libitum throughout the study period. The SE and mortality groups were inoculated orally with 0.1 mL of 107 cfu of SE phage type 6a. Four chicks were sacrificed prior to SE inoculation. At days 1, 3, 5, 7, 14 and 21 post-inoculation (pi), four chicks each from the SE and control groups were sacrificed. The study showed that there was no significant difference (p>0.05) between the SE and control groups in weight gain throughout the trial. The SE group showed clinical signs of listlessness, ruffled feathers and mild diarrhoea from day 3 pi until day 14 pi: slightly pinkish diarrhoea during the first 7 days pi but watery to pasty dark brownish thereafter. The gross and histological changes of the liver, spleen, ileum, caecum and caecal tonsil were only mild ranging from mild congestion, degeneration and necrosis to mild inflammation. No mortality was recorded. The study indicates that SE phage type 6a isolate of Malaysia is of low pathogenicity in one-day old SPF chicks

Pathogenicity of fowl adenovirus isolates in specific pathogen-free embryonated chicken eggs

Fowl adenovirus (FAdV) is the primary pathogen in inclusion body hepatitis(IBH) in chickens and causes sudden onset of mortality in broiler and layer chickens. Inclusion body hepatitis outbreak has a worldwide distribution and has recently been reported in the region. The clinical signs of the infection were weakness, dehydration, ruffled feather and paleness of comb in the affected chickens. Upon necropsy, the infected chickens showed swollen liver with petechial to focal haemorrhages, hydropericardium, and gizzard erosion and haemorrhages. Isolation of the virus from clinical cases is needed to determine the pathogenicity of the avian adenovirus. Thus the objective of this study was to determine the pathogenicity of recent FAdV isolates in specific pathogen-free (SPF) embryonated chicken eggs. Two isolates of FAdV were obtained from recent outbreaks of the disease in layer (Group A) and broiler (Group B) chicken farms. Isolate from each liver sample was processed and inoculated in SPF eggs. The eggs were harvested and liver of the embryo collected for preparation of FAdV inocula. Sixty 9-day-old SPF embryonated chicken eggs were used in the study. They were divided into three major groups, namely, Group A [A1 (sacrifice) and A2 (mortality)], B [B1 (sacrifice) and B2 (mortality)] and C [C1 (sacrifice) and C2 (mortality)]. Five eggs each from Groups A2, B2 and C2 were labeled as mortality groups and observed for mortality throughout the trial. Twenty eggs from Groups A and B were inoculated with 0.1 mL FAdV isolates A and B, respectively. Twenty eggs from Group C were not inoculated and served as the control group. The eggs were candled twice daily and mortality recorded. Three eggs each from Groups A1, B1 and C1 were sacrificed at days 1, 3, 6, 9 and 12 post-inoculation (pi). At necropsy, the gross lesions were recorded and liver, gizzard and chorioallantoic membrane (CAM) samples were fixed in 10% buffered formalin for histological examination. The study showed 100% mortalities in Groups A and B within 1 to 9 days pi for the mortality group. The control group had no mortality throughout the trials. The number of dead embryo from the sacrifice group was 7 and 11 in the groups A and B, respectively. Control group did not show mortality. Gross lesions in the sacrifice group of Group A were mainly observed in the CAM, liver and gizzard. The CAM became thickened and cloudy beginning day 3 pi. Lesions in the liver revealed enlarged, pale, petechial haemorrhages with multifocal area of necrosis, which were first observed on day 6 pi. The gizzard was congested at day 9 pi. The gross lesions observed in Group B were mainly in the CAM and liver. The lesions were observed as early as day 3 pi with thickening and cloudiness of the CAM as well as enlargement, pale to yellowish liver. The control group remained normal throughout the trial. Histologically, typical intranuclear inclusion bodies were observed in the CAM, liver and gizzard in Group A. The lesions were confined to the CAM and liver in Group B. It was concluded that FAdV is highly pathogenic to SPF embryonated chicken eggs and the embryonic liver should be used for isolation and propagation of the virus

Pathogenicity of a Malaysian infectious bronchitis virus isolate in specific pathogen free chickens

Infectious bronchitis (IB) is one of very important diseases in chicken. It is caused by IB virus (IBV) from the Coronaviridae family. This disease is a worldwide, acute and highly contagious disease. The virus easily changes in nature and emerges as a new strain and causes problems. In Malaysia, the nephrogenic strain was detected in 1995 and the new variant QX strain was reported recently in 2009. These 2 strains caused high mortality and loss of production. Hence, the objectives of this study were to isolate and identify IBV from chickens during field outbreaks of the disease in 2009 and determine the clinical signs, gross and histological lesions of specific pathogen free (SPF) chicken infected with the IBV isolate. Samples of lungs, kidneys and trachea from suspected IB birds were tested by reverse transcriptase polymerase chain reaction (RT-PCR) assay and then inoculated to 10-day old SPF embryonated chicken eggs via allantoic route for virus isolation, propagation and preparation of the IBV inoculum. The allantoic fluid and chorioallantoic membranes (CAM) from the inoculated eggs were then tested for the presence of IBV before inoculated into SPF chicken. Seventy-two day old SPF chicken were divided into 3 groups known as Groups A, B and C. Groups A and B were inoculated with IBV inocula 0.1 mL via intranasal route while group C remained as uninoculated and served as control group. Four chickens were sacrificed prior to IBV inoculation. At days 1, 3, 5, 7, 14 and 21 post-inoculation (pi), four chickens from group A and C were sacrificed. The bodyweight was noted prior to sacrifice. On necropsy, gross lesions were recorded and samples of trachea and kidneys were collected and fixed in 10% buffered formalin for histological examination. Mortality and any abnormal clinical signs were recorded at least twice a day. Feed and drink were given ad libitum. The results showed that IBV was successfully detected from the trachea, lung and kidney samples of the chickens by RT-PCR. Infectious Bronchitis Virus was successfully isolated and propagated in SPF embryonated chicken eggs and detected in the allantoic fluids and CAM. The pathogenicity study showed that the IBV isolate caused severe respiratory signs and high mortality (60%) up to day 14 pi. Mild to severe gross and histological lesions were recorded in the trachea and kidneys up to day 14 pi. However, signs of recovery with mild respiratory signs, absence of mortality and mild kidney lesions were recorded at day 21 pi. It was concluded that the IBV isolate is highly pathogenic and might be a new or variant strain of IBV

Pathogenicity of salmonella enteritidis phage types 3A and 35 after experimental infection of white leg horn chicks.

Out of 155 newly hatched SPF White Leghorn chicks, five chicks were randomly separated to confirm the SPF status of the chicks before inoculation. The remaining 150 chicks were divided into six groups. The three sacrificed groups (A, B and C) of 30 chicks each and their respective three mortality groups (MA, MB and MC) of 20 chicks each. The chicks in groups A and MA, and in groups B and MB were challenged orally with 0.1mL containing 107 cfu of SE phage type 3A(UPM-0541) and SE phage type 35 ( UPM-0525), respectively. The un-inoculated groups C and MC served as negative controls. Pathogenicity of Salmonella enteri caserovar enteritidis (S.Enteritidis) phage types (PTs) 3A and 35 infections was determined through inoculation orally with (0.1mL/chick) 107 colony forming units (cfu). Clinical signs and mortality were observed for 21 days post inoculation (pi). Body weights, bacterial isolation, gross lesions and histological lesions were recorded on days 1, 3,5,7,14 and 21pi. The inoculated chicks in A and B groups showed clinical signs of depression, anorexia, ruffled feathers, vent pasting and diarrhea starting from day 1pi. Lifting of wings from thorax was observed in group A only at day 5 and 7pi. The chicks in MA and MB groups that died during experiment showed all the clinical sings before death. There was no significant difference (p>0.05) in body weight gain among the inoculated and the control groups. The growth index value (0.035) for all the groups remained increased. The mortality caused by SE PT3A and PT35 was 10% and 5%, respectively. About 20-10% inoculated sacrificed and all the dead birds showed gross lesions of enlarged livers, fibrinous perihepatitis and pericarditis which was supported by histopathology. The Salmonella was isolated from the cultured samples of chicks inoculated with SE PT3A and SE PT35 throughout the experiment period with the individual variation of chicks and samples. It was concluded that newly hatched SPF chicks are susceptible to PT3A and PT35 infections. These phage types are mild to moderately pathogenic for SPF chicks

Pathogenicity of Salmonella enteritidis phage types 6A and 7 in experimentally infected chicks

Pathogenicity of Salmonela enterica serovar enteritdis (S.E) phage types (PTs) 6A and 7 were determined in oraly inoculated newly hatched specific pathogen fre (SPF) chicks. Clinical signs and mortality were observed daily. Body weights, bacterial isolation, gros lesions and histological lesions were recorded on days 1, 3, 5, 7, 14 and 21 post inoculations (pi). Out of 15 newly hatched SPF White Leghorn chicks, five chicks were randomly separated to confirm the SPF status of the chicks before inoculation. The remaining chicks were divided into thre sacrificed groups (A, B and C) of 30 chicks each and their respective thre mortality groups (MA, MB and MC) of 20 chicks each. Groups A and MA, and groups B and MB were inoculated oraly with 0.1mL containing 107 cfu of SE PT6A (UPM-0527) and SE PT7 (UPM-0530), respectively. The un-inoculated groups C and MC served as negative controls. Chicks in groups A and B showed clinical signs of depresion, anorexia, rufled feathers, vent pasting and diarhea starting from day 1 pi. Lifting of wings from thorax was observed in group A and B from day 1 and 5 pi, respectively. There was significant diference (p<0.05) in body weight gain among the inoculated and the control groups on days 14 and 21 pi. Growth index values were 0.035, 0.036 and 0.037 for groups A, B and C, respectively. Mortality of 20% was recorded only in MA group. Gos lesions of unabsorbed yolk, airsaculits, fibrinous pericardits, fibrinous perihapatis, enlarged kidneys, splenomegaly and dehydration were observed in about 15% of sacrificed chicks in group A and 10% in group B. Mild to moderate lesions were observed under microscope. Salmonela was isolated from the cultured samples of group A and B throughout the experiment period with the individual variation of chicks and samples. It was concluded that newly hatched SPF chicks are susceptible to PT6A and PT7 infections. These SE PTs are mild to moderately pathogenic for SPF chicks. SE PT6A is more pathogenic than SE PT7