Browsing by Author "Muhairwa, Amandus"

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Innate Immune Genes Associated With Newcastle Disease Virus Load in Chick Embryos From Inbred and Outbred Lines
(Frontiers in Microbiology, 2019-06-20) Schilling, Megan; Memari, Sahar; Cattadori, Isabella; Katani, Robab; Muhairwa, Amandus; Buza, Joram; Kapur, Vivek
Newcastle disease virus (NDV) causes substantial economic losses to smallholder farmers in low- and middle-income countries with high levels of morbidity and mortality in poultry flocks. Previous investigations have suggested differing levels of susceptibility to NDV between specific inbred lines and amongst breeds of chickens, however, the mechanisms contributing to this remain poorly understood. Studies have shown that some of these differences in levels of susceptibility to NDV infection may be accounted for by variability in the innate immune response amongst various breeds of poultry to NDV infection. Recent studies, in inbred Fayoumi and Leghorn lines, uncovered conserved, breed-dependent, and subline-dependent responses. To better understand the role of innate immune genes in engendering a protective immune response, we assessed the transcriptional responses to NDV of three highly outbred Tanzanian local chicken ecotypes, the Kuchi, the Morogoro Medium, and the Ching’wekwe. Hierarchical clustering and principal coordinate analysis of the gene expression profiles of 21-day old chick embryos infected with NDV clustered in an ecotype-dependent manner and was consistent with the relative viral loads for each of the three ecotypes. The Kuchi and Morogoro Medium exhibit significantly higher viral loads than the Ching’wekwe. The results show that the outbred ecotypes with increased levels of expression of CCL4, NOS2, and SOCS1 also had higher viral loads. The higher expression of SOCS1 is inconsistent with the expression in inbred lines. These differences may uncover new mechanisms or pathways in these populations that may have otherwise been overlooked when examining the response in highly inbred lines. Taken together, our findings provide insights on the specific conserved and differentially expressed innate immune-related genes involved the response of highly outbred chicken lines to NDV. This also suggests that several of the specific innate immunity related genes identified in the current investigation may serve as markers for the selection of chickens with reduced susceptibility to NDV.
Prevalence, characterization and antimicrobial resistance profiles of Salmonella isolates from healthy broiler and free-range chickens in Morogoro, Tanzania
(AJOL, 2022-06-13) Munuo, Lidia; Katakweba, Abdul; Lyimo, Beatus; Muhairwa, Amandus
Background: Salmonella enterica is a group of bacteria that cause enteric and systemic infection in animals and humans worldwide. Objectives: The study was conducted to determine the prevalence, characterization, and antimicrobial susceptibility profiles of Non-Typhoidal Salmonella in indigenous free-range and broiler chickens in Morogoro Municipality. Methodology: A cross-sectional study was conducted from November 2019 to May 2020 whereby 384 cloaca swab samples from health chickens from Magadu, Mzinga, and Bigwa wards were collected. Identification was done by standard bacteriological methods, serotyping, and genetically confirmed by PCR using Salmonella specific primers pair and Salmonella enterica primer pair (invA and iroB gene primers). A sensitivity test was done using Ampicillin, Tetracycline, Imipenem, Gentamycin, Ciprofloxacin, Sulfamethoxazole trimethoprim, and Cefaclor antimicrobial discs. The descriptive statistic method was used for analysis and paired t-test assuming unequal variance was used for comparing overall prevalence of Salmonella spp between free range and broiler chickens. Results: Out of 384 samples, 11 (2.9%) samples were confirmed to be Salmonella of which 8(4%) were from broilers and 3(1.6%) were from free range chickens. Of the 11 isolates, 8 were from group B serotypes and 3 isolates were from group D serotypes. Susceptibility results showed a variable level of sensitivity to the majority of antibiotics tested; however, levels of resistance were also found in 7/11 isolates resistant to Ampicillin, 4/11 isolates resistant to sulfamethoxazole-trimethoprim, and 3/11 isolates resistant to tetracycline. Three isolates were found to harbor Sulfamethoxazole(sulII) resistant gene. Conclusion: This study revealed the presence of Salmonella carrier among chickens kept in Morogoro with antimicrobial resistances from both free range and broilers chickens. The results underline the importance of the biosecurity measures in the production and processing of chicken for human consumption, similarly, improvement of management is recommende