RESUMEN
The movement of persons during the pandemic has played a significant role in increasing the disease transmission rates as well as the spread of COVID-19 variants from one region to another. Although, strict restrictions on movement of persons across borders had been imposed early on in the pandemic, countries had to open up their borders to travel as a way of trying to resuscitate their economies that were declining due to closure of businesses and restriction on both local and international travel. Although the lifting of travel bans was done under strict regulations, there has since been a spike in the number of infection cases and spread of virus variants. These increases have certainly put a lot of strain on the rather limited resources allocated to fighting COVID-19 in most regions including the Eastern and Southern Africa. In this manuscript, we examine the potential role played by cross-border movements on the number of detected cases in a developing country. Here, we consider cases where persons cross borders through either designated controlled border points with proper facilitation for screening and detection of potentially infected cases, as well as border crossings through ungazatted points. The persons crossing borders are considered to be either susceptible, exposed or infected with no or mild symptom. A mathematical model was formulated to cater for the aforementioned classifications as well as additional important dynamics related to the disease. The behaviour of solutions for the model is determined and the conditions for existence of the disease free equilibrium as well as the disease persistent equilibrium ascertained. Finally, a dynamically consistent nonstandard finite difference scheme is proposed to replicate the properties of the continuous model. The baseline model was fitted to data of two waves, parameter values were determined and used to obtain numerical results. Our results show that, an increase in cross border movement can result in an increase in the number of detected cases. We observed that if the number of persons who cross-border points while positive for COVID-19 is reduced by 60%, the total number of detected cases can be reduced by up to 58%. In addition, an 83% increase in immigration of exposed persons can increase the disease burden in a destination country by at least 14%. These results justify border points closures during a pandemic or imposing very stringent measure across borders to curtail the importation of positive cases in a country.
RESUMEN
Methicillin-resistant Staphylococcus aureus (MRSA) and third-generation cephalosporin-resistant Escherichia coli (3GCREc) are community and hospital-associated pathogens causing serious infections among populations by infiltrating into hospitals and surrounding environment. These main multi-drug resistant or antimicrobial resistance (AMR) bacterial pathogens are threats to human health if not properly tackled and controlled. Tackling antimicrobial resistance (AMR) is one of the issues for the World Health Organization (WHO) to design a comprehensive set of interventions which also helps to achieve the end results of the developing indicators proposed by the same organization. A deterministic mathematical model is developed and studied to investigate the impact of the WHO policy on integrated antimicrobial stewardship activities to use effective protection measures to control the spread of AMR diseases such as MRSA and 3GCREc in hospital settings by incorporating the contribution of the healthcare workers in a hospital and the environment in the transmission dynamics of the diseases. The model also takes into account the parameters describing various intervention measures and is used to quantify their contribution in containing the diseases. The impact of combinations of various possible control measures on the overall dynamics of the disease under study is investigated. The model analysis suggests that the contribution of the interventions: screening and isolating the newly admitted patients, improving the hygiene in hospital settings, decolonizing the pathogen carriers, and increasing the frequency of disinfecting the hospital environment are effective tools to contain the disease from invading the population. The study revealed that without any intervention, the diseases will continue to be a major cause of morbidity and mortality in the affected communities. In addition, the study indicates that a coordinated implementation of the integrated control measures suggested by WHO is more effective in curtailing the spread of the diseases than piecemeal strategies. Numerical experiments are provided to support the theoretical analysis.