http://hdl.handle.net/123456789/133 2026-04-08T10:21:11Z http://hdl.handle.net/123456789/2222 SEROPREVALENCE, MOLECULAR AND CLINICAL EPIDEMIOLOGY OF AVIAN METAPNEUMOVIRUS INFECTION IN THREE SELECTED CLIMATIC ZONES IN NIGERIA BAKRE, Adetolase Azizat Avian metapneumovirus (aMPV) causes an immunosuppressive disease of the upper respiratory tract of chickens and turkeys, leading to substantial economic loss in poultry production. Despite the significant global burden of this disease, little is known about its endemicity, distinguishing clinical features, circulating virus subtypes and the role of climate in its occurrence in Nigeria. This study was designed to investigate aMPV seroprevalence, circulating subtypes, clinical presentation and predisposing factors in Nigeria. Using a cross-sectional study design and simple random sampling technique, blood was collected from 480 apparently healthy commercial chickens from states within three climatic zones of Nigeria: near-temperate (Plateau, n=160), rainforest (Oyo, n=160) and semi-arid (Sokoto, n=160) during the dry and wet seasons between December 2018 and September 2019. Harvested sera were tested for aMPV antibodies using indirect ELISA. A total of 168 tissue samples including conjunctivae, turbinates, tracheae and lungs (n=42 each) were collected from carcasses from chicken flocks with signs of respiratory distress presented at Veterinary diagnostic facilities in the study areas between December 2019 and April 2020 for virus detection using RT-PCR to amplify the N- and G-genes of the virus. Amplicons were sequenced using Sanger’s method and phylogenetic analysis was performed with appropriate software. Pretested questionnaires were administered to 42 owners of the sampled flocks to access information on clinical presentations and antibiotic usage during respiratory disease outbreaks. Thereafter, RT-PCR-positive samples were processed for virus isolation in Specific-Antibody-Negative embryonated chicken eggs. Bacteria associated with aMPV-positive tissues were isolated and identified using standard methods. Data were analysed using descriptive statistics and ANOVA at α0.05. The aMPV seroprevalence rates were 100.0, 48.8 and 56.2% for Plateau, Oyo and Sokoto states, respectively, during the dry season and 52.5, 36.2 and 65.0%, in the wet season. Mean antibody titers were significantly higher in the dry season (4757.9±223.5, 1414.0±158.0 and 2800.9±313.1) than wet season (670.7±74.9, 499.4±55.8 and 548.8±61.4) for Plateau, Oyo and Sokoto states, respectively. Turbinate and conjunctiva samples from five flocks (11.9 %) of layer chickens of all age groups were positive for aMPV in Plateau State with significant association between near temperate zone and the occurrence of the disease. Phylogenetic analysis revealed that the Nigerian aMPV strain clustered with European and Asian subtype B strains with unique mutations (T12I, G223E and A238V) in the G-gene. Clinical signs presented by aMPV-positive flocks included rales, coughing, sneezing and dyspnoea while the commonly used antibiotics by farmers were tylosin (71.4%), doxycycline (66.7%) and enrofloxacin (59.5%), without prescription. Virus isolation from aMPV-positive tissues was unsuccessful while secondary bacteria isolated included Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. Avian metapneumovirus infection associated with a more virulent Subtype B strain was widespread in commercial layers in the study areas, with the turbinate and conjunctivae being the predilection sites. Associations with Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae were established, while transmission was aided by low environmental temperature and humidity. Routine vaccination of commercial chickens using homologous virus strains is recommended. 2023-05-01T00:00:00Z http://hdl.handle.net/123456789/1671 THERAPEUTIC EFFICACY AND MECHANISMS OF ACTION OF PERSEAAMERICANA EXTRACTS ON HYPERTENSION AND CARDIO-RENAL OXIDATIVE STRESS INDUCED BY NΩ-NITRO-L-ARGININE METHYL ESTER ADEJUMOBI, OLUMUYIWA ABIOLA Cardiovascular diseases are the leading causes of death worldwide with hypertension being the major risk factor. The adverse effects of synthetic medications have made the search for safer and effective herbal therapies imperative. Persea americana(PA) is a medicinal plant with diverse health benefits. There is dearth of information on its safety and efficacy in the management of hypertension.The safety and ameliorative effects of PA extractson NΩ-Nitro-L-Arginine Methyl Ester (L-NAME) induced hypertension and cardiorenal oxidative stress were investigated. In vitro anti-inflammatory and anti-hypertensive assays were carried out separately on methanol PA leaf (PALE), stem bark (PABE), and root (PARE) extracts (UIH22531). Standard in vitro protocols were adopted using gallic acid, indomethacin and captopril, respectively, as standard drugs. Half maximum Inhibition Concentrations (IC50) were calculated using IC50 calibration curve. Male Wistar rats (7 groups, n=4/group) received distilled water (control) and variable doses of PA extracts (1000, 2000, 4000, 5000, 6000 and 7500 mg/kg) once to determine the Lethal Dose (LD50). Antihypertensive effect of PA was evaluated using 120 male rats randomly allotted to 12 groups (n=10). These received distilled water, L-NAME (40 mg/kg), L-NAME+ PALE (100, 200, 400 mg/kg), L-NAME + PABE (100, 200, 400 mg/kg) and L-NAME + PARE (100, 200, 400 mg/kg) and L-NAME + lisinopril (0.28 mg/kg). Blood pressure (BP) measurement and electrocardiogram were performed. Immunoreactivity of NF-ĸB, marker of oxidative stress: Malondialdehyde (MDA) and antioxidants: Superoxide dismutase(SOD) and Reduced Glutathione (GSH) were evaluated in the cardiac and renal tissues. Data were analysed using descriptive statistics and ANOVA at α0.05. Persea americana extracts demonstrated anti-inflammatory activities with IC50 of the PALE (100.86±2.77), PABE (101.54±9.01) and PARE (101.74±13.10) comparable to Indomethacin (115.09±1.62). The extracts had anti-hypertensive activities with IC50 of 135.99±10.06, 29.64±0.92, 48.61±6.56, respectively, for PALE, PABE and PARE comparable to captopril (IC50 = 41.86±2.10). LD50 (mg/kg) for PALE, PABE and PARE were 3162.30, 3463.90 and 5477.20, respectively. Persea americana extracts significantly reduced systolic BP (mmHg) from 224.33±11.89 to110±31.87 (PALE-200), 113.67±9.49 (PABE-200) and 111.33±17.84 (PARE-200). A significant increase in QT interval (ms) in hypertensive rats (106.00±1.00) compared to the control (45.33±26.03) was reduced to 62.00±11.53 (PALE-100), 67.67±11.66 (PABE-200) and 62.67±1.53 (PARE-100) better than lisinopril (86.00±10.64). Treatment of hypertensive rats with PA extracts caused significant reduction in NF-ĸB expression, cardiac MDA (µmol/mgprotein) from 0.87±0.25 to 0.44±0.08 (PALE-200), 0.55±0.14 (PABE-200) and 0.33±0.22 (PARE-200) as well as renal MDA from 1.11±0.04 to 0.41±0.14 (PALE-200), 0.60±0.19 (PABE-200) and 0.74±0.18 (PARE-200). Cardiac SOD (units/mgprotein) increased from 1.19±0.05 to24.03±5.74 (PALE-200), 15.12±6.07 (PABE-200) and 11.27±1.03 (PARE-200) and renal SOD from 5.27±4.13 to 7.59±0.99 (PALE-200), 16.19±0.85 (PABE-200) and 9.59±1.05 (PARE-200). Cardiac GSH (µmol/mgprotein) increased from 51.82±13.20 to 88.37±1.55 (PALE-200), 73.77±11.53 (PABE-200) and 68.86±7.99 (PARE-200) comparable to lisinopril (68.74±3.68). Persea americana is safe and effective at 200 mg/kg, ameliorating hypertension induced cardio-renal damages through free radical scavenging and anti-inflammatory activities. Thus, the plant is recommendedfor the management of hypertension and cardio-renal dysfunction. 2021-08-01T00:00:00Z http://hdl.handle.net/123456789/1669 SEROPREVALENCE AND MOLECULAR CHARACTERISATION ON INFECTIOUS BRONCHITIS VIRUS IN CHICKENS IN SOUTHWESTERN NIGERIA JOLAOSO, TAIWO OLUWOLE Infectious Bronchitis (IB), a viral respiratory disease of chickens is a major threat to the poultry industry causing decreased egg production. Despite vaccination against the disease, outbreaks continue to occur in Nigeria with clinical features similar to other respiratory diseases. There is limited information on the circulating andavailable vaccine strains in southwestern Nigeria. This study was designed to investigate the level of awareness of farmers, experience of outbreaks by veterinarians, available vaccines and current seroprevalence of IBas well as characterise circulating virus in commercial and local chickens in Lagos, Ogun and Oyo states. Structured questionnaires were interviewer administered purposively to obtain information on IB awareness from 83, 105 and 96 registered poultry farmers (based on accessibility) as well as experience of outbreak from 56, 64 and 70 veterinarians (based on poultry specialisation) in Lagos, Ogun and Oyo states, respectively, between September and November, 2015. A survey of commercially available IB vaccines was also conducted.Blood, cloacal and oropharyngeal swabs were obtained from 10 chickens per unvaccinated commercial flock from 15 randomly selected poultry farms per state. One hundred similar samples were obtained from unvaccinated local chickens in five locations per state. Cloacal and oropharyngeal swabs, lung and kidney tissues from21dead commercial chickens with history of respiratory signs were obtainedfrom poultry diseases diagnostic centers in the studyarea. Sera were screened for IB virus antibodies using ELISA, while other samples were subjected to reverse transcription polymerase chain reaction for virus detection. Purified 1b, S1 and NP genes were sequenced using Sanger’s method. Nucleotide and amino acid sequences were aligned with sequences retrieved from GenBank using software. Phylogenetic analysis was performed using the Neighbour-Joining method. Data were analysed using descriptive statistics, ANOVA and independent t-test at α0.05. Among the farmers, only 27.7%, 24.8%, and 28.1% were aware of IB, 22.9%, 19.0% and 24.0% vaccinated their chickens, while 10.8%, 19.0% and 10.4% had experienced outbreaks in Lagos, Ogun and Oyo states, respectively. Among the veterinarians, 28.0%, 37.0% and 30.0% had encountered IB outbreaks, while 72.0%, 55.5% and 66.0% advised farmers to vaccinate in Lagos, Ogun and Oyo states, respectively. Massachusetts strain H120 was the only IB vaccine strain available. Seroprevalence was 83.3%, 88.0% and 76.0% in commercial chickens and 70.0%, 85.0% and 82.0% in local chickens in Lagos, Ogun and Oyo states, respectively. Mean antibody titers were significantly higher in commercial chickens (49.74±2.50 and 43.25±4.64) than in local chickens (24.71±2.02 and 31.85±2.24), respectively, from Lagos and Oyo states. Phylogenetic analysis of the 1b and S1 gene sequences showed that detected IB virus strains clustered with Dutch Strain H120 Variant 2 (Israel) and Italian strain Qx, while analysis of the NP gene revealed 98-99% similarity with South Korean strain K210. High prevalence of infectious bronchitis among chickens in Lagos, Ogun and Oyo states was established with circulating strains of the virus being genetically diverse from the available vaccine strain. Vaccines for use in southwestern Nigeria should be produced from homologous strains detected. 2021-07-01T00:00:00Z http://hdl.handle.net/123456789/1402 DEVELOPMENTAL BIOLOGY AND NEUROGENESIS IN THE PRENATAL AFRICAN GREATER CANE RAT (Thryonomys swinderianus, Temminck 1827) OLUWASEUN, AHMED MUSTAPHA The African Greater Cane Rat (AGCR) is a precocial hystricomorph rodent largely restricted to the African ecosystem. The drive for home-grown animal research models within the African context has increased studies on the biology and development of this rodent. However, information on prenatal development of this rodent is currently scarce. This study was designed to describe the sequence of morphogenetic developmental milestones in the developing AGCR embryos/foetuses, and to elucidate the prenatal corticogenesis of the developing AGCR brain. Nineteen timed primi-gravid AGCR does from Gestation Day (GD) 10 to 140 (every 10 days) were used. Sonographic examinations were conducted to determine time-based prenatal parameters. The AGCR were subsequently anaesthetised, dissected and their embryos/foetuses (n = 54) explanted. Embryos/foetuses were then staged based on morphogenetic characteristics of prenatal development in mammals with Carnegie and Štӗrba systems. Brains were harvested for gross morphological description and evaluation of morphometric parameters (height, length and width). Brain samples were processed using immunofluorescence biomarkers to determine the pattern, onset, duration and peak of neurogenesis (Pax6, Tbr1, Tbr2, NF, HuCD, MAP2), gliogenesis (GFAP, Olig2) and myelinogenesis (MBP) in the prenatal AGCR. Quantitative analysis of individual neural progenitor cells and Olig2+ cells, as well as radial thickness of the ventricular zones were evaluated. Data were analysed using one-way ANOVA and linear regression at α0.05. The earliest detectable sonographic feature of pregnancy in the AGCR was the gestational sac at GD20, while at GD 50 the first gross indication of an embryo was seen Staging of the AGCR embryos/foetuses revealed a relatively longer period of embryogenesis in the AGCR compared to humans and other precocial rodents like the guinea pig and agouti. Grossly, gyrencephalization of the neocortex was first noticed by GD90 and continued till GD130. Lobation patterning of the cerebellum was the last distinct gross developmental feature noticed in the prenatal AGCR brain at GD130. Brain height (0.67±0.03 to 1.35±0.07 cm), length (0.88±0.02 to 2.85±0.07 cm) and width (0.56±0.04 to 2.02±0.04 cm) increased significantly from GD60 to GD140. There was a positive correlation between gestational length and each brain parameters measured (height: r = 0.58; length: r = 0.86 and width: r = 0.87). The period of pureneural stem cell proliferation in the developing AGCR was identified at GD50. By GD60, the radial thickness of the ventricular zone had reached its maximum depth, while the peak period of neurogenesis was at GD80. Axonal and dendritic sprouting had begun by GD80 and this progressed until birth. Deep and upper layers of the neocortex were established in an “inside-out” manner by GD120 and GD130, respectively. Active gliogenesis spanned GD110 - 130. Although, oligodendrocyte progenitor cell proliferation had started by GD80, myelinogenesis did not begin earlier than GD120. The sequences of morphogenetic developmental milestones and prenatal corticogenesis in the African Greater Cane Rat were consistent with the precocity of central nervous system development in the guinea pig. The African Greater Cane Rat is therefore suitable as a research model for neurodevelopmental studies. 2021-02-01T00:00:00Z