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BackgroundNewcastle disease is still a serious disease of poultry especially in backyard free-range production systems despite the availability of cross protective vaccines. Healthy-looking poultry from live bird markets have been suspected as a major source of disease spread although limited studies have been conducted to ascertain the presence of the virulent strains in the markets and to understand how they are related to outbreak strains.MethodsThis study evaluated the occurrence of Newcastle disease virus in samples collected from poultry in live bird markets across Uganda. The isolates were pathoyped using standard methods (mean death time (MDT), intracelebral pathogenicity index (ICPI), and sequencing of the fusion protein cleavage site motif) and also phylogenetically analysed after sequencing of the full fusion and hemagglutin-neuraminidase genes. The isolates were classified into genotypes and subgenotypes based on the full fusion protein gene classification system and compared with other strains in the region and world-wide.ResultsVirulent avian paramyxovirus type I (APMV-1) (Newcastle disease virus) was isolated in healthy-looking poultry in live bird markets. The viruses belonged to a new subgenotype, Vd, in genotype V, and clustered together with Tanzania and Kenya strains. They harbored low genetic diversity.ConclusionThe occurrence of virulent AMPV-1 strains in live bird markets may serve as sources of Newcastle disease outbreaks in non-commercial farms.

IntroductionTo meet key millennium development goals, the rural population needs to be reached for health assessment and service delivery. Gastroduodenal ulcer disease is a common ailment affecting the health of people in Uganda. A cross-sectional study was conducted at Bwera Hospital in Kasese district of western Uganda, to establish the prevalence and predisposing factors of Helicobacter pylori among gastroduodenal ulcer disease patients.MethodsA sample of 174 patients with symptoms of gastroduodenal ulcer disease was purposively obtained. Using two laboratory test methods, the prevalence of H. pylori among these patients was determined. A structured questionnaire was administered to participants to establish their demographic background and selected aspects of their lifestyle. Finally, the results obtained by enzyme-linked immunosorbent assay (ELISA) and immunochromatographic rapid test (IRT) were compared.ResultsWe established the prevalence of H. pylori as 29.9% (52/174) by ELISA and 37.4% (65/174) by IRT. Cigarette smoking, poor sanitation, and lack of formal education were the significant predisposing factors with p-values <0.05. The two tests gave identical results in 87.9% of the patients.DiscussionThe prevalence of H. pylori by IRT and ELISA test methods was similar to what has been reported elsewhere in developed countries; but was lower than previously reported in developing countries including Uganda. The previous studies in Uganda were carried out in the urban population and on young children; and some used antibody-detection methods only, therefore leading to different prevalence as a result of difference in study population and methods.

AimsTo determine antibacterial activity of Ocimum suave essential oils against bacterial uropathogens.Study DesignA cross sectional and experimental study.Place and Duration of StudySix selected hospitals in Bushenyi District, Uganda between June 2012 and July 2013.MethodologyClean catch midstream urine samples were collected and inoculated on Cystine Lysine Electrolyte Deficient (CLED) agar. The plates were incubated at 37°C for 24hrs to 48hrs. The O. suave essential oils were extracted by hydrodistillation of leaves for 4hrs using a Clevenger apparatus. The oil was collected and dried over anhydrous sodium sulphate (Na2SO4) and kept at 4°C till further use. The antimicrobial activity of O. suave essential oils against isolates was determined by agar well method. The MIC of O. suave essential oil extract was carried out by microbroth dilution method.ResultsOf the three hundred (300) midstream urine samples collected, 67(22.33%) had significant bacterial growth. Escherichia coli is the most common isolate (61.19%, n = 41). The essential oil from O. suave showed activity against isolates of E. coli, K. pneumoniae, S. aureus, E. feacalis, M. morganii, Citrobacter species, Enterobacter species and P. aeruginosa with mean zone of inhibition (ZI) ranging from 10–22 mm. The essential oils had no inhibitory activity on Acinetobacter species. The minimum inhibitory concentration (MIC) for O. suave essential oils ranged from 0.78 to 22 μg/ml. This study showed that O. suave essential oils had MIC value of 0.78 μg/ml against S. aureus and MIC values ranging from 3 to 22 μg/ml against the other tested isolates.ConclusionThe most common uropathogen was E. coli (61.19% n = 41). O. suave essential oils exhibited antibacterial activity against majority of the uropathogens, except Acinetobacter species, mean ZI of 10–22 mm and MIC of 0.78 – 22 μg/ml.

Although there are over 90 serotypes of Streptococcus pneumoniae, antimicrobial resistance is predominantly found in a limited number of serotypes/serogroups, namely 6, 9, 14, 19 and 23. There is no compelling mechanism to account for this restriction. We aimed to determine whether serotypes commonly associated with drug resistance have higher transformation frequencies than those that are susceptible to antimicrobial agents. An in vitro investigation of the genetic transformation frequency of drug-resistant serotypes compared with that of susceptible serotypes under the influence of synthetic competence-stimulating peptides was performed. The transforming DNA was genomic DNA carrying a Tn916-like transposon containing the mefE gene that confers resistance to erythromycin. It was observed that serotypes 6, 9, 14, 19 and 23, which are highly associated with drug resistance, do not exhibit a higher degree of transformation efficiency than other serotypes. These findings suggest that the association of serotype with drug resistance is likely due to prolonged exposure to transforming DNA resulting from longer nasopharyngeal carriage and to a greater selective pressure from antimicrobials, particularly in children. This is the first study to compare the transformation frequencies of pneumococcal clinical isolates using genomic DNA that carries the composite Tn916-like element.

Vaccine failures after Newcastle disease vaccination with the current commercial vaccines have been reported and are associated with many factors, including genotypic and antigenic differences between vaccine and outbreak strains, although all APMV-1 members belong to one serotype. We assessed the immunoprotection ability of four thermostable, low-virulent Newcastle disease-virus isolates from Ugandan waterfowl against challenge with a virulent strain (MDT = 36.8 h, ICPI = 1.78) isolated from morbid chicken. Six-week-old commercial Leghorn layers, challenged at 21 days post immunization were used. Four isolates designated: NDV-133/UG/MU/2011, NDV-177/UG/MU/2011, NDV-178/UG/MU/2011 and NDV-173/UG/MU/2011 induced mean haemagglutinin inhibition antibody titres of log 9.3, 8.2, 6.3 and 2.0, respectively, at 21 days post immunization. The antibody titres correlated with the protection rates (R² = 0.86, p < 0.007) of 60%, 50%, 20% and 0% of birds, respectively, against challenge at 14 days post challenge. Further evaluation of these and more low-virulent isolates might provide an alternative to the current commercial vaccine failures.

Uganda is a Newcastle disease (ND) endemic country where the disease is controlled by vaccination using live LaSota (genotype II) and I2 (genotype I) vaccine strains. Resurgent outbreak episodes call for an urgent need to understand the antigenic diversity of circulating wild Avian Avulavirus serotype-1 (AAvV-1) strains. High mutation rates and the continuous emergence of genetic and antigenic variants that evade immunity make non-segmented RNA viruses difficult to control. Antigenic and functional analysis of the key viral surface proteins is a crucial step in understanding the antigen diversity between vaccine lineages and the endemic wild ND viruses in Uganda and designing ND peptide vaccines. In this study, we used computational analysis, phylogenetic characterization, and structural modeling to detect evolutionary forces affecting the predicted immune-dominant fusion (F) and hemagglutinin-neuraminidase (HN) proteins of AAvV-1 isolates from waterfowl and poultry in Uganda compared with that in LaSota vaccine strain. Our findings indicate that mutational amino acid variations at the F protein in LaSota strain, 25 poultry wild-type and 30 waterfowl wild-type isolates were distributed at regions including the functional domains of B-cell epitopes or N-glycosylation sites, cleavage site, fusion site that account for strain variations. Similarly, conserved regions of HN protein in 25 Ugandan domestic fowl isolates and the representative vaccine strain varied at the flanking regions and potential linear B-cell epitope. The fusion sites, signal peptides, cleavage sites, transmembrane domains, potential B-cell epitopes, and other specific regions of the two protein types in vaccine and wild viruses varied considerably at structure by effective online epitope prediction programs. Cleavage site of the waterfowl isolates had a typical avirulent motif of 111GGRQGR'L117 with the exception of one isolate which showed a virulent motif of 111GGRQKR'F117. All the poultry isolates showed the 111GRRQKR'F117 motif corresponding to virulent strains. Amino acid sequence variations in both HN and F proteins of AAvV-1 isolates from poultry, waterfowl, and vaccine strain were distributed over the length of the proteins with no detectable pattern, but using the experimentally derived 3D structure data revealed key-mapped mutations on the surfaces of the predicted conformational epitopes encompassing the experimental major neutralizing epitopes. The phylogenic tree constructed using the full F gene and partial F gene sequences of the isolates from poultry and waterfowl respectively, showed that Ugandan ND aquatic bird and poultry isolates share some functional amino acids in F sequences yet do remain unique at structure and the B-cell epitopes. Recombination analyses showed that the C-terminus and the rest of the F gene in poultry isolates originated from prevalent velogenic strains. Altogether, these could provide rationale for antigenic diversity in wild ND isolates of Uganda compared with the current ND vaccine strains.

BackgroundUganda poultry production is still faced with frequent outbreaks of Newcastle disease (ND) in the backyard free-range systems despite the accessibility of cross protective vaccines. Live bird markets and waterfowl has long been reported as a major source of disease spread as well as potential sources of avirulent strains that may mutate to virulent strains. ND-virus has been reported enzootic in Ugandan poultry but limited studies have been conducted to ascertain thermostability phenotypes of the Ugandan ND-virus strains and to understand how these relate to vaccine strains.MethodsThis study evaluated thermostability of 168 ND-virus field isolates recovered from live bird markets and waterfowls in Uganda compared to two live commercial vaccine strains (I2 and LaSota) by standard thermostability procedures and Hemagglutinin-Neuraminidase (HN) gene domains. The known pathotypes with thermostability profiles were compared at HN amino acid sequences.ResultsField isolates displayed disparate heat stability and HN gene domains. Thermolabile isolates were inactivated within 15 min, while the most thermostable isolates were inactivated in 120 min. Four thermostable isolates had more than 2 log2 heamaglutinin (HA) titers during heat treatment and the infectivity of 9.8 geometric mean of log10 EID50 % in embryonated eggs. One isolate from this study exhibited a comparable thermostability and stable infectivity titers after serial passages, to that of reference commercial vaccine was recommended for immunogenicity and protection studies.ConclusionThe occurrence of ND-virus strains in waterfowl and live bird markets with disparate thermostability and varying HN gene domains indicate circulation of different thermostable and thermolabile ND-virus pathotypes in the country.