Analysis of a mathematical model of influenza dynamics with drug resistance aspect

Paper presented at the 4th Strathmore International Mathematics Conference (SIMC 2017), 19 - 23 June 2017, Strathmore University, Nairobi, Kenya.Influenza has posed a terrific public health concern. It has led to unacceptably high mortality rates especially to immune compromised persons worldwide. Efforts to effectively treat and combat the spread of influenza can be put in place if its dynamics are well understood. Numerous challenges have been faced in the event of controlling the spread and eradicating this pandemic, a major impediment being the rise of drug resistance. In light of this, a deterministic model is formulated and used to analyze the transmission dynamics of influenza having incorporated the aspect of drug resistance. A system of differential equations that models the transmission dynamics of influenza is developed. The basic reproduction number (R0) is calculated and stability of the equilibrium points analyzed. Results of the analysis show that there exists a locally stable disease free equilibrium point, E0 when R0 < 1 and a unique endemic equilibrium E*, when R0 > 1. The effect of drug resistance and transmission rate of the resistant virus on the infected and the recovered is discussed.Pan African University Institute of Basic Sciences, Kenya. Technical University of Kenya

Burden, clinical characteristics, risk factors, and seasonality of adenovirus 40/41 diarrhea in children in eight low-resource settings

Background: The application of molecular diagnostics has identified enteric group adenovirus serotypes 40 and 41 as important causes of diarrhea in children. However, many aspects of the epidemiology of adenovirus 40/41 diarrhea have not been described.Methods: We used data from the 8-site Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project birth cohort study to describe site- and age-specific incidence, risk factors, clinical characteristics, and seasonality.Results: The incidence of adenovirus 40/41 diarrhea was substantially higher by quantitative polymerase chain reaction than enzyme immunoassay and peaked at ∼30 episodes per 100 child-years in children aged 7-15 months, with substantial variation in incidence between sites. A significant burden was also seen in children 0-6 months of age, higher than other viral etiologies with the exception of rotavirus. Children with adenovirus 40/41 diarrhea were more likely to have a fever than children with norovirus, sapovirus, and astrovirus (adjusted odds ratio [aOR], 1.62; 95% CI, 1.16-2.26) but less likely than children with rotavirus (aOR, 0.66; 95% CI, 0.49-0.91). Exclusive breastfeeding was strongly protective against adenovirus 40/41 diarrhea (hazard ratio, 0.64; 95% CI, 0.48-0.85), but no other risk factors were identified. The seasonality of adenovirus 40/41 diarrhea varied substantially between sites and did not have clear associations with seasonal variations in temperature or rainfall.Conclusions: This study supports the situation of adenovirus 40/41 as a pathogen of substantial importance, especially in infants. Fever was a distinguishing characteristic in comparison to other nonrotavirus viral etiologies, and promotion of exclusive breastfeeding may reduce the high observed burden in the first 6 months of life

Mathematical Analysis of Influenza A Dynamics in the Emergence of Drug Resistance

Every year, influenza causes high morbidity and mortality especially among the immunocompromised persons worldwide. The emergence of drug resistance has been a major challenge in curbing the spread of influenza. In this paper, a mathematical model is formulated and used to analyze the transmission dynamics of influenza A virus having incorporated the aspect of drug resistance. The qualitative analysis of the model is given in terms of the control reproduction number, Rc. The model equilibria are computed and stability analysis carried out. The model is found to exhibit backward bifurcation prompting the need to lower Rc to a critical value Rc∗ for effective disease control. Sensitivity analysis results reveal that vaccine efficacy is the parameter with the most control over the spread of influenza. Numerical simulations reveal that despite vaccination reducing the reproduction number below unity, influenza still persists in the population. Hence, it is essential, in addition to vaccination, to apply other strategies to curb the spread of influenza

Application of Optimal Control to Influenza Pneumonia Coinfection with Antiviral Resistance

Influenza and pneumonia independently lead to high morbidity and mortality annually among the human population globally; however, a glaring fact is that influenza pneumonia coinfection is more vicious and it is a threat to public health. Emergence of antiviral resistance is a major impediment in the control of the coinfection. In this paper, a deterministic mathematical model illustrating the transmission dynamics of influenza pneumonia coinfection is formulated having incorporated antiviral resistance. Optimal control theory is then applied to investigate optimal strategies for controlling the coinfection using prevalence reduction and treatment as the system control variables. Pontryagin’s maximum principle is used to characterize the optimal control. The derived optimality system is solved numerically using the Runge–Kutta-based forward-backward sweep method. Simulation results reveal that implementation of prevention measures is sufficient to eradicate influenza pneumonia coinfection from a given population. The prevention measures could be social distancing, vaccination, curbing mutation and reassortment, and curbing interspecies movement of the influenza virus

Analysis of three novels as representative models of Kenyan Literature’s suitability for filmic adaptation

In the multi-media creative space, a close relationship exists between literature and film. Writers and film creators employ their unique skills to make their audience visualize: the former mentally, the latter through audio-visual senses. The distinction between the two media types lies in the perception of the visual image and concept of the mental image, which informs the adaptation of prose fiction, particularly novels. Global and regional level film producers adapt literary works into film, yet in the Kenyan context, a creative disconnect exists between literary works and their film adaptations. Generationally popular Kenyan literary texts are deficiently adapted into Kenyan film. The study evaluated three novels, namely The River and The Source, Striving for the Wind and Dust as representative models of Kenyan Literature’s suitability for adaptation. It was guided by the Reader Response Theory, Intertextuality and Adaptation Theory. In view of the qualitative and quantitative nature of the study, a mixed methods research design was employed. The study drew its primary data from Jicho Four Productions’ adaptations of Ogola’s The River and the Source, close reading of Ogola’s The River and the Source, Mwangi’s Striving for the Wind, and Owour’s Dust, alongside semi-structured interviews of fourteen persons purposively sampled from across literature and film industries, utilizing mixed questionnaires. The study finds that Kenyan Literature and Kenyan Film as solid creative pillars exist individually, without a bridge to substantitively link them and their audiences. This research is significant as it gives insights to the barriers to adaptations of Kenyan Literature into film, untapped potential of adaptations, internal and external standard-based yardsticks influencing adaptations, and provides a structured outline of stumbling blocks and potential remedies to enable film adaptations of Kenyan Literature to be at par with regional and global counterparts

Multiple micronutrients fortified salt: consumers’ acceptability survey, Tanzania

Abstract Background Food fortification with micronutrients is an insufficiently used technology in developing countries. Salt is consumed in small, constant daily amounts by most people globally. Salt has been instrumental in delivering iodine to a wide population globally through fortification. There is a proven effective technology for fortifying iodinated salt with iron, folate, and Vitamin B12. Findings have shown that both Double (Iodine and iron) fortified salt (DFS) and quadruple (iron, iodine, folate, and vitamin B12) fortified salt (QFS) are effective in raising hemoglobin levels. Aim To assess the acceptability and gauge consumers’ willingness to use double-fortified and quadruple-fortified salt formulations. Methods We conducted an observational study involving 300 households at Haydom Lutheran Hospital catchment area in Northern rural Tanzania between October 2021 and April 2022. Each household was supplied with one type of salt (iodized salt (IS), DFS or QFS) for cooking common family dishes for one week. Thereafter, at least two adult members of the family who used the dishes cooked with study salt were interviewed using the adopted 5-point Hedonic scale. Results A total of 899 individuals were interviewed after using study salt for one week: 286 IS, 305 DFS, and 308 QFS. The overall acceptability for the salts was QFS (82%), DFS (78%), and IS (79%). The mean sensory (taste, color and appearance) scores of the QFS (1.7) and DFS (1.7) were comparable to standard iodized salt (1.6). Conclusion Quadruple-fortified salt and double-fortified salt are equally acceptable and have similar sensory scores as standard iodized salt when used to cook commonly eaten dishes in the study population

Genotypic antimicrobial resistance assays for use on E. coli isolates and stool specimens.

Antimicrobial resistance (AMR) is an emerging public health problem and methods for surveillance are needed. We designed 85 sequence-specific PCR reactions to detect 79 genes or mutations associated with resistance across 10 major antimicrobial classes, with a focus on E. coli. The 85 qPCR assays demonstrated >99.9% concordance with sequencing. We evaluated the correlation between genotypic resistance markers and phenotypic susceptibility results on 239 E. coli isolates. Both sensitivity and specificity exceeded 90% for ampicillin, ceftriaxone, cefepime, imipenem, ciprofloxacin, azithromycin, gentamicin, amikacin, trimethoprim/sulfamethoxazole, tetracycline, and chloramphenicol phenotypic susceptibility results. We then evaluated the assays on direct stool specimens and observed a sensitivity of 97% ± 5 but, as expected, a lower specificity of 75% ± 31 versus the genotype of the E. coli cultured from stool. Finally, the assays were incorporated into a convenient TaqMan Array Card (TAC) format. These assays may be useful for tracking AMR in E. coli isolates or directly in stool for targeted testing of the fecal antibiotic resistome