Reseach articles

Modeling the effects of contaminated environments on the transmission dynamics of avian influenza in humans and domestic birds

Mon, 01 Sep 2025 00:00:00 GMT

Modeling the effects of contaminated environments on the transmission dynamics of avian influenza in humans and domestic birds Soka, Serapia P.; Mayengo, Maranya Makuru; Kgosimore, Moatlhodi Avian influenza is a viral infection that affects birds and can spread to humans and other animals, causing severe illness and high mortality in both populations. Migratory birds are the primary transmitters of the virus, shedding it into the environment. This study investigates the effects of contaminated environments in the transmission dynamics of avian influenza. We suggest a deterministic mathematical model to capture the interactions between humans, domestic birds, and contaminated environments.....

Coffee farmers’ perception of climate change trends in Gimbi district, Western Ethiopia

Sun, 01 Dec 2024 00:00:00 GMT

Coffee farmers’ perception of climate change trends in Gimbi district, Western Ethiopia Chemeda, Beshea Abdissa; Senbeta, Feyera; Birhane, Emiru Climate change and variability pose substantial threats to rain-fed agriculture, critically impacting the livelihoods of rural communities in Ethiopia. The Gimbi District, recognized for its high agricultural potential within the West Wellega Zone, faces severe repercussions from recurrent droughts attributable to climate change. This study critically examines the perceptions of coffee farmers regarding climate change and its consequential effects on food crop production within the Gimbi District. Employing a multistage sampling method, 402 coffee farmers were selected across six kebeles. Additionally, areal gridded surface monthly rainfall and temperature data spanning from 1990 to 2020 were sourced from the Ethiopian Meteorological Institute. The finding reveals that 92% of coffee farmers perceived significant unpredictability in rainfall during the study period. Furthermore, 84% of respondents noted an increase in temperature, while 10% observed a decrease. The modified Mann–Kendall trend test indicated a decline in rainy season rainfall by 69 mm per decade. Concurrently, mean annual temperature exhibited a statistically significant increase (p < 0.001) of approximately 0.31 °C per decade, aligning with the farmers' perceptions. In response to the adverse impacts of climate change, farmers have implemented diverse adaptation strategies, including soil and water conservation as well as crop and livestock management practices. This study underscores the critical need for enhanced adaptive capacities to mitigate the detrimental effects of climate variability on rain-fed agriculture. The alignment between farmers' perceptions and empirical meteorological data further emphasizes the urgency of developing resilient agricultural practices. The article was published under gold open access licensing.

Modeling salmonellosis transmission dynamics in humans and dairy cattle with optimal controls.

Sat, 01 Feb 2025 00:00:00 GMT

Modeling salmonellosis transmission dynamics in humans and dairy cattle with optimal controls. Trazias, Herman; Irunde, Jacob; Kgosimore, Moatlhodi; Mayengo, Maranya In this paper, we develop a mathematical model to examine the transmission dynamics and control analysis of salmonellosis in humans and dairy cattle. The model considers three time-dependent controls (improving hygiene, vaccination, and organic acid disinfectants), human and dairy cattle populations, and Salmonella typhimurium bacteria in the environments and dairy products. The next generation matrix technique is applied to compute the effective reproduction number R that gauges the persistence and extinction of salmonellosis while adopting the proposed control interventions. The stability behavior of the equilibrium states is examined using the Lypunov function method based on the effective reproduction number R. The Latin hypercube sampling and the partial rank correlation coefficient methods are used to investigate the sensitivity and uncertainty of input parameters against model outputs. The results indicate that improving hygiene and vaccination can eliminate salmonellosis. Improving hygiene habits at a rate of at least 0.9 per day is recommended to eliminate salmonellosis. An efficacious vaccine that can immunize at least 85% of the vaccinated dairy cattle is also recommended to eradicate salmonellosis if it can be implemented to vaccinate susceptible dairy cattle at a rate of at least 0.45 per day for the first 30 days of the salmonellosis outbreak. The use of all three controls is recommended to eliminate salmonellosis quickly and at the lowest cost. The article is published under CC BY-NC-ND 4.0 and CC BY-NC licenses.

Dynamical modeling of Salmonellosis in humans and dairy cattle with temperature and pH effects.

Fri, 20 Dec 2024 00:00:00 GMT

Dynamical modeling of Salmonellosis in humans and dairy cattle with temperature and pH effects. Trazias, Herman; Mayengo, Maranya; Irunde, Jacob; Kgosimore, Moatlhodi Approximately 20 million cases and 0.15 million human fatalities worldwide each year are caused by Salmonellosis. A mechanistic compartmental model based on ordinary differential equations is proposed to evaluate the effects of temperature and pH on the transmission dynamics of Salmonellosis. The transmission potential of the disease in areas with temperature and pH stresses is examined. The next-generation matrix method is applied to compute the temperature-pH-dependent reproduction number ℛPT. The dynamical regimes of the system are examined using Lyapunov stability theory and backward bifurcation analysis. The uncertainty and global sensitivity analysis are examined using the Latin Hypercube Sampling (LHS) and Partial Rank Correlation Coefficient (PRCC) methods. The numerical simulations of the proposed model under favorable and unfavorable temperatures are performed with a 95% confidence interval (CI) for the reliability assessment of the model parameters. The analysis shows that the ingestion rates of Salmonella enterica subsp. enterica serovar Typhimurium bacteria in humans and dairy cattle, human-to-human transmission rate, cattle-to-cattle transmission rate, human shedding rate, dairy cattle shedding rate, and the rate of producing contaminated dairy products are directly proportional to the number of infected humans and infected dairy cattle. The temperature ranges of 100C−200C and 300C−400C and pHs greater than 3.8 have a significant effect on the dynamics of Salmonellosis. In order to eliminate Salmonellosis, the study recommends treating natural water bodies using the recommended chemical disinfectants during summer seasons and in areas with temperature ranges of 100C−200C, cooking food at the hottest temperatures, and storing food at the lowest temperatures for all pHs. The article was published under CC BY-NC-ND 4.0 and CC BY-NC licenses.