Severe Depletion Of Lymphocytes Research Articles

Invasive Pulmonary Aspergillosis after COVID-19 Pneumonia.

COVID-19 emerged in China in late 2019 and quickly spread worldwide. The severe immunomodulation and depletion of lymphocytes caused by the virus and its therapy led to an increase in the incidence of superinfections. COVID-19-associated pulmonary aspergillosis (CAPA) is a new entity with increasing incidence and high associated mortality.We present the case of a 68-year-old patient admitted to our ward after recovering from severe COVID-19 pneumonia. Due to worsening of her clinical condition, chest computed tomography was performed and a lung abscess was documented with the identification of Aspergillus niger. Despite therapy with voriconazole, the patient’s condition deteriorated, culminating in her death.LEARNING POINTSCOVID-19-associated pulmonary aspergillosis (CAPA) is a new entity with an increasing incidence.It is a serious and life-threatening complication in patients with severe COVID-19 even in the absence of the classic risk factors for invasive pulmonary aspergillosis.Clinical suspicion is crucial since a timely diagnosis and treatment have a major impact on prognosis.

Molecular Characterization and Demographic Study on Infectious Bursal Disease Virus in Faisalabad District.

The re-emergence of virulent strains of the Infectious Bursal Disease Virus (IBDV) leads to significant economic losses of poultry industry in Pakistan during last few years. This disease causes the infection of bursa, which leads to major immune losses. A total number of 30 samples from five IBD outbreaks during the period of 2019-20 were collected from different areas of Faisalabad district, Pakistan and assayed by targeting the IBD virus VP2 region through RT-PCR. Among all the outbreaks, almost 80% of poultry birds were found positive for the IBDV. The bursa tissues were collected from the infected birds and histopathological examination of samples revealed severe lymphocytic depletion, infiltration of inflammatory cells, and necrosis of the bursa of Fabricius (BF). Positive samples were subjected to re-isolation and molecular characterization of IBDV. The Pakistan IBDV genes were subjected to DNA sequencing to determine the virus nucleotide sequences. The sequences of 100 Serotype-I IBDVs showing nearest homology were compared and identified with the study sequence. The construction of the phylogenetic tree for nucleotide sequences was accomplished by the neighbor-joining method in MEGA-6 with reference strains. The VP2 segment reassortment of IBDVs carrying segment A were identified as one important type of circulating strains in Pakistan. The findings indicated the molecular features of the Pakistan IBDV strains playing a role in the evolution of new strains of the virus, which will contribute to the vaccine selection and effective prevention of the disease.

COVID-19-Associated Pulmonary Aspergillosis, March-August 2020.

Pneumonia caused by severe acute respiratory syndrome coronavirus 2 emerged in China at the end of 2019. Because of the severe immunomodulation and lymphocyte depletion caused by this virus and the subsequent administration of drugs directed at the immune system, we anticipated that patients might experience fungal superinfection. We collected data from 186 patients who had coronavirus disease–associated pulmonary aspergillosis (CAPA) worldwide during March–August 2020. Overall, 182 patients were admitted to the intensive care unit (ICU), including 180 with acute respiratory distress syndrome and 175 who received mechanical ventilation. CAPA was diagnosed a median of 10 days after coronavirus disease diagnosis. Aspergillus fumigatus was identified in 80.3% of patient cultures, 4 of which were azole-resistant. Most (52.7%) patients received voriconazole. In total, 52.2% of patients died; of the deaths, 33.0% were attributed to CAPA. We found that the cumulative incidence of CAPA in the ICU ranged from 1.0% to 39.1%.

COVID-19: B-Cell Depletion and Sepsis Related Changes in Bone Marrow and Spleen

COVID-19: B-Cell Depletion and Sepsis Related Changes in Bone Marrow and Spleen

Pathological and virological analysis of concurrent disease of chicken anemia virus infection and infectious bronchitis in Japanese native chicks.

A concurrent infection of chicken anemia virus (CAV) and infectious bronchitis virus (IBV) was detected in Japanese native chicks in 2017, in which a high mortality rate (97.7%) was recorded in a small flock of 130 chicks exhibiting poor growth. Histological examination revealed that the affected chicks exhibited two different pathological entities: one was severe hematopoietic and lymphocytic depletion with abnormally large cells containing intranuclear inclusion bodies of CAV, whereas the other was renal tubular necrosis due to IBV infection. Immunohistochemistry detected CAV antigens in the bone marrow, liver, and spleen as well as IBV antigens in the kidneys, trachea, and air sacs. CAV was isolated from the liver sample of the chicks, and the isolated strain was designated as CAV/Japan/HS1/17. A phylogenetic analysis of the CAV VP1 gene revealed that CAV/Japan/HS1/17 is genetically similar to Chinese strains collected from 2014 to 2016. An experimental infection was performed using CAV/Japan/HS1/17 and specific-pathogen-free chicks to determine the pathogenicity of CAV/Japan/HS1/17. The isolate caused 100% anemia and 70% mortality to chicks inoculated at one day old, 80% of chicks inoculated at seven days old also developed anemia, and 10% died from CAV infection. These results suggest that the unusually high mortality in Japanese native chicks can be attributed to dual infection with both CAV and IBV. The results of the experimental infection suggest that CAV/Japan/HS1/17 has a pathogenic potential to specific-pathogen-free chicks and a relatively higher pathogenicity than previous Japanese CAV strains.

Newcastle Disease Virus Vaccines Based On Genotype VII Strains Provide Efficient Protection Against Challenge With Circulating Very Virulent Field Virus (Genotype VII) In Broiler Chickens

Newcastle disease virus (NDV) outbreaks still occur and cause disastrous economic losses in broiler chickens despite intensive vaccination policies using genetically different vaccines from the circulating strains. This study aimed to compare protection conferred by different vaccination strategies using genotype matched (genotype VII) and mismatched vaccine (genotype I and II) against challenge with currently circulating viruses in broiler chickens. 175 one- day-old broiler chicks were divided in to 5 groups. Groups 1 to 4 (G1, G2, G3 and G4) were vaccinated using genotype I (Ulster 2C strain), genotype II (VG/GA strain) and genotype VII (KBNP-4152R2L strain) vaccines according to manufacturer's instructions and group 5 (G5) was kept as control. Protection assessed based on clinical protection, seroconversion, shedding and histopathology.Chickens vaccinated with live genotype II vaccine at 7 and 21 days of age and killed genotype VII vaccine at 7 days of age (G2) were completely protected clinically with no mortality compared with control non vaccinated chickens (G5) that showed typical NDV clinical picture with (100%) mortality. while, other vaccinated groups showed lower level of clinical protection with (2.8%) mortality for each group. Viral shedding was greatly reduced in groups vaccinated with inactivated recombinant genotype VII vaccine (G2 and G3) which recorded (0% & 0%) and (16.6% & 0%) at 7 & 10 days post challenge, respectively compared with groups vaccinated with inactivated genotype II vaccine (G1 and G4) regardless the genotype of the combined live vaccine (either genotype II or VII). Moreover, histopathology of control non vaccinated challenged group (G5) revealed severe lymphocytic depletion and necrosis, epithelial degeneration beside neurological lesions. It was concluded that using genotype matched NDV vaccine with the currently circulating field strains can provide adequate clinical protection and minimize virus shedding that can help in decreasing virus load in the environment.

Samsum ant venom modulates the immune response and redox status at the acute toxic dose in vivo.

Background: Ant venoms express surface molecules that participate in antigen presentation involving pro- and anti-inflammatory cytokines. This work aims to investigate the expression of MHC-II, CD80 and CD86 on the polymorphonuclear cells (PMNs) in rats injected with samsum ant venom (SAV).Methods: Rats were divided into three groups - control, SAV-treated (intraperitoneal route, 600 μg/kg), and SAV-treated (subcutaneous route, 600 μg/kg). After five doses, animals were euthanized and samples collected for analysis.Results: The subcutaneous SAV-trated rats presented decreased levels of glutathione with increased cholesterol and triglyceride levels. Intraperitoneal SAV-treated animals displayed significantly reduced concentrations of both IFN-γ and IL-17 in comparison with the control group. However, intraperitoneal and subcutaneous SAV-treated rats were able to upregulate the expressions of MHC-II, CD80 and CD86 on PMNs in comparison with the control respectively. The histological examination showed severe lymphocyte depletion in the splenic white pulp of the intraperitoneal SAV-injected rats.Conclusion: Stimulation of PMNs by SAV leads to upregulation of MHC-II, CD 80, and CD 86, which plays critical roles in antigen presentation and consequently proliferation of T-cells. Subcutaneous route was more efficient than intraperitoneal by elevating MHC-II, CD80 and CD86 expression, disturbing oxidative stability and increasing lipogram concentration.

Leucogram, serum protein parameters and histopathology of broiler chickens (<i>Gallus gallus domesticus</i>) treated with cyclophosphamide and infected with velogenic Newcastle disease virus

The present study evaluated the changes in leucogram, serum protein parameters and histology of lymphoid organs associated with cyclophosphamide–induced immunosuppression in broiler chickens infected with velogenic Newcastle disease virus. At four-week-old, one hundred broiler chickens were randomly assigned into four groups of 25 each viz: A/CYTI – cyclophosphamide treated and velogenic Newcastle disease virus infected, B/CYTU – cyclophosphamide– treated and uninfected, C/CYNTI – cyclophosphamide non-treated, infected and D/CYNTU– untreated uninfected. Groups A/CYTI and B/CYTU were injected with cyclophosphamide at the dose of 75mg/kg body weight daily for 3 days while groups A/CYTI and C/CYTU were infected with velogenic Newcastle disease virus at six-week-old. Blood samples were collected from randomly selected chickens in each group for leucogram and serum protein assays, while tissue samples were collected for histopathology. Cyclophosphamide induced significantly (P < 0.05) lower levels of circulating total leucocytes, lymphocytes and heterophils on days 7 and 14 post-treatment. On day 14 post-treatment, the total serum protein values of groups A/CYTI and B/CYTU were significantly (P < 0.05) lower than those of groups C/CYNTI and D/CYNTU. Examination of the tissue sections showed severe diffused lymphocytic necrosis and depletion in the bursa, spleen and thymus. Newcastle disease virus infection induced significantly (P < 0.05) higher levels of circulating total leucocytes, lymphocytes and heterophils and significantly (P< 0.05) decreased serum proteins in cyclophosphamide treated chickens on day 3 PC. The results showed that severe decreased leucogram and serum proteins and lymphoid cell depletion in cyclophosphamide treated broiler chickens, which together with the increased leukogram observed following velogenic Newcastle disease virus infection could be used as indicators of exposure to immunosuppressants.Keywords: Broiler chickens, Cyclophosphamide, Leucogram, Serum proteins, Newcastle disease

Comparative pathological changes in sheep infected with Theileria annulata and non-infected control

The hematological, serum biochemical and histopathological variations were compared in sheep naturally infected with Theileria annulata and healthy control group. Peripheral blood smears of 300 suspected sheep were observed for the presence of Theileria by microscopy (24%) and confirmed through PCR (34%). The PCR confirmed samples were used for further studies and showed significant decrease in hemoglobin concentration, packed cell volume (PCV), total erythrocyte counts, total leukocyte count, serum total proteins, creatinine and glucose (P &lt; 0.05) as compared to healthy control. Similarly a significant increase was recorded in Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P&lt; 0.05) as compared to non-infected sheep. Histopathological changes revealed edema and severe depletion of lymphocytes in lymph nodes. The present study concluded that ovine theileriosis was linked with some pathological alterations in blood and tissues which could be helpful in the diagnosis of disease.

Response of cyclophosphamide-treated broiler chickens to challenge with velogenic Newcastle disease virus

ABSTRACTThis study investigated whether prior cyclophosphamide (CY) treatment influenced the susceptibility of young broiler chickens to velogenic Newcastle disease (vND) virus (vNDV) challenge. Broiler chickens treated with CY at 4 weeks of age showed a loss of weight, severe atrophy of the bursa and thymus and severe lymphocytic depletion in the bursa, spleen and thymus and lymphopaenia. On challenge at 6 weeks of age with vNDV, there were significant (p < .05) weight loss, severe depression, diarrhoea, coughing and sero-mucous nasal discharges and torticollis. Lesions included severe atrophy of the lymphoid organs and congested lungs. Proventricular, intestinal and caecal tonsil haemorrhages and ulcers were more severe in the CY-untreated than the treated broilers. Histopathology showed severe necrosis and depletion of the lymphocytes in the lymphoid organs, perivascular cuffin and endotheliosis in the brain. Total mortalities in the CY-treated and untreated broilers were 100% and 94.44%, respectively, by day 6 post-challenge. There was no statistical difference (p < .05) between the mortalities. These results show that CY treatment may not have an effect on the susceptibility of broilers to an acute disease like vND.

Background data on NOD/Shi-scid IL-2Rγnull mice (NOG mice).

To obtain background data of NOD/Shi-scid IL-2Rγnull (NOG) mice, severely immunedeficient mice, a total of 120 animals were examined at 7, 26 and 52 weeks-old (20 mice/sex/group). The survival rate at 52 weeks-old was 95% (19/20) in both sexes. Clinically, circling behavior in one direction along the cage wall was observed in males after 8 weeks and females after 47 weeks-old, and hunchback position was found in males after 32 weeks-old. Hematologically, lymphocyte count markedly decreased at all ages, while white blood cell count increased in several mice at 52 weeks-old. Blood chemistry results revealed high values of aspartate aminotransferase, lactate dehydrogenase and creatine phosphokinase in some females at 26 weeks-old, without any related histological change. Histologically, lymphoid hypoplasia characterized by severe lymphocyte depletion with poorly developed tissue architectures was observed. In addition, spongiotic change in the nerve tissue was observed in both sexes at 7 and 26 weeks-old, and intracytoplasmic materials known as tubular aggregates in the skeletal muscles were found in males terminated at 26 and 52 weeks-old and in females at 52 weeks-old. Malignant lymphoma was found in one female euthanized at 20 weeks-old. Further, small intestinal adenoma, hepatocellular adenoma, leukemia, cerebral lipomatous hamartoma, Harderian gland adenoma and uterine polyp were also observed, and their incidences were low except for that of uterine polyp. This study provided detailed background data on NOG mice up to 52 weeks-old and provided information on appropriate use of NOG mice in the various research fields.

Pathological Studies on Infectious Bronchitis Disease in Chickens

Infectious bronchitis virus has been recognized as highly contagious disease in chickens. In this study, 138 birds from 10 broiler chicken flocks that suffered from respiratory disease were examined to study the pathological lesions associated with IBV infection in naturally infected flocks. Moreover, the infection was confirmed via virus isolation and PCR. Samples were harvested from both Sharkia and Gharbia provinces during one year. The clinical examination of the investigated birds showed nasal discharges, gasping and rales. Congested trachea with lumen contained mucus and caseated material at the biforcation of the two main bronchi were characteristic in most of the necropsied birds. The kidneys were enlarged and dark red or pale with the presence of whitish precipitate in the ureters. Four isolates recovered from four different broilers chicken’s flocks were further analyzed by S1 glycoprotein gene sequencing. The phylogenetic analysis of the deduced amino acids sequences of the four strains revealed that they were closely related to the IBV Egyptian variant 2 and IS/1494/2006 strains. The histopathological examination of the kidneys showed focal aggregation of lymphocytes in the renal cortex and the medulla. The liver showed multiple focal areas of necrosis which replaced by lymphocyte and heterophils aggregation. The spleen showed thickened capsule with subcapsular hemorrhage and mild to severe focal depletion of lymphocytes. Trachea, lung, proventriculus, intestine and bursa showed hyperplasia and degenerative changes in their epithelium. Blood vessels showed endotheliosis with perivascular edema and leukocyte infiltration in various organs. Edema was also seen in heart, trachea and lungs. Finally, it could be concluded that infectious bronchitis virus is a major cause and strongly implicated in respiratory and/or renal problems of the Egyptian broiler chicken flocks. Moreover, Egyptian variant 2 still evolving and causing severe damage to renal tissue and various organs.

Porcine circovirus 2 immunology and viral evolution.

Porcine circovirus 2 (PCV2) has and is still causing important economic losses to pig industry. This is due to PCV2-systemic disease (PCV2-SD), formerly known as postweaning multi-systemic wasting syndrome (PMWS), which increases mortality rates and slows down the growth of the animals, as well as other conditions collectively included within the so-called porcine circovirus diseases (PCVD). PCV2-SD affected pigs are considered to be immunosuppressed, with severe lymphocyte depletion and evidence of secondary infections. However, PCV2-infected pigs not developing the disease are able to mount humoral and cellular immune responses and clear the virus or limit the infection. On the contrary, insufficient amounts of neutralizing antibodies have been linked to increased PCV2 replication, severe lymphoid lesions and development of PCV2-SD. Central role in controlling PCV2 infection are played by the antigen specific memory T cells. These cells persist long term post-infection or vaccination and are able to expand rapidly after recall antigen recognition. Most farms in the main pig producing countries are applying vaccination against PCV2 to prevent the disease and improve the farm performance. Vaccines do not induce sterilizing immunity and PCV2 keeps on circulating even in farms applying vaccination. This, together with the high mutation rate of PCV2, world-wide fluctuations in the genotype dominance and emergence of novel genetic variants, warrant close molecular survey of the virus in the field.

Severe lymphopenia is associated with elevated plasma interleukin-15 levels and increased mortality during severe sepsis.

Sepsis-related mortality has been found increased in RAG-1 knockout mice. However, in patients admitted to medical intensive care units, it is unknown whether severe lymphocyte depletion at admission is associated with increased interleukin (IL)-7 and IL-15 levels in circulation, and increased mortality. We prospectively enrolled 92 patients who were admitted to medical intensive care units for severe sepsis or septic shock. At admission, 24 patients (26.1%) had severe lymphopenia, defined as lymphocyte counts of less than 0.5 × 10(3)/μL. Severe lymphopenia was associated with significantly higher plasma levels of tumor necrosis factor α, IL-6, IL-8, and IL-10 and was also independently associated with 28-day mortality (adjusted hazard ratio, 3.532; 95% confidence interval, 1.482-8.416; P = 0.004). The levels of plasma IL-15, but not IL-7, were increased modestly in patients with severe lymphopenia compared with those without (median, 12.2 vs. 6.4 pg/mL; P = 0.005). The elevated plasma IL-15 levels were contrarily associated with significantly decreased B-cell lymphoma 2 mRNA expression in peripheral blood mononuclear cells. In conclusion, severe lymphopenia was associated with increased mortality in patients with severe sepsis. We found that patients with sepsis with severe lymphopenia had down-regulated B-cell lymphoma 2 mRNA expression in peripheral blood mononuclear cells, despite increased plasma IL-15 concentrations. Whether IL-7 and IL-15 are insufficient in patients with severe lymphopenia during severe sepsis warrants further investigations.

Pathology and molecular diagnosis of chicken infectious anemia in Rhode Island Red (RIR) flocks in natural outbreaks

The present study was carried out to investigate the outbreak of chicken infectious anaemia (CIA) in field condition of Vidharbha region of Maharashtra. A total of 45 birds were brought from four flocks for systemic necropsy. The samples were collected for histopathology as well as PCR analysis for characterization of CIA infections. The necropsy showed that there was severe anemia indicated by paleness of comb, wattle and visceral organs. Atrophy of the thymus along with the mild atrophy of bursa was also noticed. Liver and bone marrow were pale in appearance. Kidneys were swollen and pale. Microscopically, marked hypoplasia of haemopoitic cells in the bone marrow, severe depletion of lymphocytes from lymphoid organs such as thymus, bursa and spleen were noticed along with mild to severe hemorrhages in the visceral organs of affected birds. PCR assay using specific primers for VP1 gene (1300bp) of CIA virus confirmed the CIA infection. The results of present study confirmed the presence of CIAV infection in RIR birds in current outbreaks.

Natural peste des petits ruminants virus infection in Black Bengal goats: virological, pathological and immunohistochemical investigation.

BackgroundPeste des Petits Ruminants (PPR), also known as Goat Plague, occurs in goats, sheep and related species. It is caused by a morbillivirus in the family Paramyxoviridae. In Bangladesh PPR is endemic and it causes serious economic losses. Pathology of PPR has been reported in different goat and sheep breeds from natural and experimental infections. Field results are better indicators of pathogenicity of the circulating virus. The severity of the disease varies with species, breed and immune status of the host. Pathological investigations of natural outbreaks of PPR in Balck Bengal goats are very limited. The current investigation was aimed at describing pathology and antigen localization in natural PPR infections in Black Bengal goats.ResultsA total of 28 outbreaks were investigated clinically and virologically. Average flock morbidity and mortality were 75% and 59%, respectively, with case fatality rate of 74%. Necropsy was conducted on 21 goats from 15 outbreaks. The major gross lesions were congestion of gastrointestinal tract, pneumonia, engorged spleen, and oedematous lymphnodes. Histopathological examination revealed severe enteritis with denudation of intestinal epithelium, severe broncho-interstitial pneumonia with macrophages within lung alveoli and extensive haemorrhages with depletion of lymphoid cells and infiltration of macrophages in the sinuses of spleen. In lymph nodes, the cortical nodules were replaced by wide sinusoids with severe depletion of lymphocytes, infiltration of mononuclear cells and some giant cells in sub-capsular areas and medullary sinuses. PPR virus antigen was found in pneumocytes and alveolar macrophages in lungs. Viral RNA could be detected by RT-PCR in 69 out of 84 nasal swab, 59 out of 84 blood and 21 out of 21 lymph node samples. Sequence analyses revealed closeness of Bangladeshi strains with other recent Asian isolates.ConclusionNatural outbreaks of PPR in Black Bengal goats in Bangladesh resulted in 75% and 59% flock morbidity and mortality, respectively, with a case fatality rate of 74%. The striking histo-morphologic diagnosis of PPR was acute pneumonia and severe gastro-enteritis. A detailed experimental pathological study on Black Bengal goats infected with recent isolates is required.

Comparative histopathological and immunological study of two field strains of chicken anemia virus.

Infection of poultry with chicken anemia virus (CAV) is implicated in several field problems in broiler flocks due to the immunosuppression generated and, consequently, the increased susceptibility to secondary infections. Recently, we have reported an increased occurrence of clinical cases caused by CAV strains distantly related to those commonly used for vaccination. In order to understand the behavior of two Argentinean CAV strains (CAV-10 and CAV-18) in two-week-old chickens, an immune and histopathological study was performed. Neither mortality nor clinical signs were observed in the infected or control groups. Thymus lobes from chickens infected with both CAV viruses were smaller compared to the negative control group. At 14 days post-infection (dpi), only chickens inoculated with CAV-10 show a severe depletion of lymphocytes in the thymus cortex and in follicles from the bursa of Fabricius. Also thymopoiesis disorders, such as reduction in the percentage of total DP (CD4 + CD8α+) thymocytes and alteration in the percentages of DP subpopulations, were more important in animals inoculated with the CAV-10 than the CAV-18 strain. In addition, only animals infected with CAV-10 show a decrease in CD8αβ splenocytes. Altogether our results show that, although both Argentinean CAV strains produce subclinical infections in chickens causing immunosuppression at 14 dpi, they might differ in their in vivo pathogenicity.

Comparative histopathological and immunological study of two field strains of chicken anemia virus

Infection of poultry with chicken anemia virus (CAV) is implicated in several field problems in broiler flocks due to the immunosuppression generated and, consequently, the increased susceptibility to secondary infections. Recently, we have reported an increased occurrence of clinical cases caused by CAV strains distantly related to those commonly used for vaccination. In order to understand the behavior of two Argentinean CAV strains (CAV-10 and CAV-18) in two-week-old chickens, an immune and histopathological study was performed. Neither mortality nor clinical signs were observed in the infected or control groups. Thymus lobes from chickens infected with both CAV viruses were smaller compared to the negative control group. At 14 days post-infection (dpi), only chickens inoculated with CAV-10 show a severe depletion of lymphocytes in the thymus cortex and in follicles from the bursa of Fabricius. Also thymopoiesis disorders, such as reduction in the percentage of total DP (CD4 + CD8α+) thymocytes and alteration in the percentages of DP subpopulations, were more important in animals inoculated with the CAV-10 than the CAV-18 strain. In addition, only animals infected with CAV-10 show a decrease in CD8αβ splenocytes. Altogether our results show that, although both Argentinean CAV strains produce subclinical infections in chickens causing immunosuppression at 14 dpi, they might differ in their in vivo pathogenicity.

Pathomorphological alterations of sub-acute selenium toxicity in broilers

The sub-acute study of sodium selenite was performed in a total number of 120 Vencobb day old healthy broilers randomly divided into four groups of 30 each. Group I broilers were given plain feed and served as control whereas, broilers of group II, III and IV were given sodium selenite @ 2, 6 and10 ppm respectively in diet, daily for 35 days. Pathomorphological changes of induced broilers of mid and high dose groups were more severe than low dose group. Grossly varying degrees of congestion and haemorrhages in trachea, lungs, liver, kidneys, intestine, thymus, brain and heart with hydropericardum and enlargement of bursa of Fabricius and thymus were noticed in treated broilers. Histological alterations consisted of congestive and haemorrhagic changes of liver, lungs, kidneys, heart, spleen, brain and thymus indicating vascular effects of sodium selenite. Treated broilers showed severe vacuolar degeneration and necrotic changes of hepatocytes accompanied by discrete mononuclear cells infiltration which suggested toxic hepatitis. Kidneys of treated broilers had massive degenerative and necrotic changes of lining epithelium of convoluted tubules accompanied by epithelial desquamation and fatty changes indicating toxic nephritis. Lymphoid organs of selenium treated broilers revealed severe depletion of lymphocytes from the germinal centre.

닭에서 저병원성 조류인플루엔자와 뉴캐슬 바이러스의 복합감염에 따른 임상적, 병리학적 연구

Both of avian influenza (AI) and Newcastle disease (ND) can cause mild to severe diease in poultry. In this study, clinical signs, macro, and micro lesions were studied. Eighteen six-week-old SPF chicks were divided into 4 groups (E1, E2, E3 and C1) and housed in different rooms of the isolation facility at CAVAC (Daejeon, Korea). The control group (C1) of 3 chicks was housed separately as uninoculated. Experimental groups (E1, E2 and E3) challenged with H9N2 and/or NDV. E1 group was challenged with 0.1 mL A/Kr/Ck/01310/01 (H9N2) <TEX>$10^{5.6}$</TEX> <TEX>$EID_{50}$</TEX> by intranasal, E2 group was challenged with 0.5 mL Kyojeongwon (KJW) <TEX>$10^{5.0}{\sim}10^{6.0}$</TEX> <TEX>$ELD_{50}$</TEX> by intramuscular, and E3 group was challenged with 0.1 mL A/Kr/Ck/01310/01 <TEX>$10^{5.6}$</TEX> <TEX>$EID_{50}$</TEX> by intranasal and 0.5 mL KJW <TEX>$10^{5.0}{\sim}10^{6.0}$</TEX> <TEX>$ELD_{50}$</TEX> by intramuscular 7 days after H9N2 challenge. In clinical signs and gross findings, E1 group showed 0% mortality, anorexia, and hemorrhage of proventriculus and thymus, E2 group showed 100% mortality within 3~5 days after challenge, anorexia, green diarrhea, hemorrhage of proventriculus, proximal esophagus and thymus, enlargement of kidney, and bronze liver, and E3 group showed 100% mortality within 24~36 hours after NDV challenge, depression, anorexia, green diarrhea, hemorrhage of proventriculus, spleen, and lung, enlargement of kidney, and reduction of thymus size and number. In histopathological examination, E1 group showed depletion and necrosis in bursa of Fabricius, thymus, and spleen, and E2 and E3 group showed severe lymphocyte depletion and necrosis with destruction of lymphoid organ structures. In conclusion, co-infection of H9N2 with ND virus causes acute disease with high mortality than single infection and the pathologic lesions were more severe.