diseases have been developed together with
determinant factors like incidence, spread, and
persistence, [1]. The SIR model was first studied by
[2] and [3], where the impact of demographic
factors like births, deaths, and migration are studied.
Later, SIR models with vital dynamics, [4] and other
forms of extensions with vaccination, treatment,
relapse, susceptibility, etc., are studied by different
authors [3], [5], [6], [7], [8], [9].
A novel disease named coronavirus (COVID -
19) disease evolved in Wuhan, China, December
2019. This disease became the most devastating
health challenge experienced in the world after the
1918/1919 pandemic of influenza. The World
Health Organization (WHO) announced the disease
as a pandemic on March 11, 2020, and by the end of
the year 2020, over 90 million cases have been
recorded and more than two million lives lost, as a
result of the COVID – 19 menace. Nigeria is one of
the most affected countries in Africa with COVID-
19 cases. By the end of year 2020, 87607 and 1361
cases of COVID – 19 infection and casualties were
recorded, [10], [11], [12], [13], while efforts by the
WHO are ongoing to circulate vaccines and possible
drugs across the world to treat and minimize the
high rate of the infection spread.
Several deterministic and stochastic models
have been derived to explain and predict the
transmission of COVID – 19 in Nigeria. A study,
[14], formulated a model with Non-Pharmaceutical
Strategies (NPIs) fitted to the prevalence date as of
March 30, 2020. Their results show that COVID –
19 can be effectively mitigated using a moderate
level of compliance with NPIs to avoid a second
wave of the pandemic. In [15], derivation of a
model was done to forecast COVID – 19 dynamics
using the prevalence data as of March 16, 2020.
Their results reveal that if at least 55 percent of
humans can adhere to social distancing and face
mask usage, the disease will be eradicated. Also if
the case findings for humans with symptoms are
increased to 0.8 per day associated with social
distancing will lead to a reduction of COVID-19
disease incidence. The studies in [16] and [17],
considered the effect of optimal management in
minimizing COVID – 19 infection in Nigeria. Other
works on the formulation of COVID – 19 using
qualitative and quantitative techniques include the
works of [18], [19], [20], [21]. The SIR model is the
basic framework for describing disease spread in
population dynamics. The recent coronavirus
(COVID-19) disease across the world has majorly
been described using the SIR model, [22], as well as
other diseases in [23], [24] and [25]. The idea of
SDM was first conceived in [26]. Also, the studies
[2] and [27], employed hybrid methods of SDM and
Laplace to compute the system of ordinary
differential equations, other works on the
application of SDM can be seen in the works of
[27], [28] and [29], while works on the modification
of SDM, using the other semi-analytical approaches
can be seen in [30], [31], [32] and [33].
Inspired by the cited works on the mathematical
modeling approach to COVID – 19 disease spread
in Nigeria together with different applications of
numerical methods to obtain approximate solutions
of models, in this work we consider fitting a SIR
model to the COVID – 19 prevalent and active cases
in Nigeria in relation to year 2020 utilizing the non-
linear least square method by the use of MAPLE
computational software, such that the estimated and
fitted values were used to analyze and obtain the
value of [25]. Also, the numerical solution of
the model using the SDM in comparison with the
RK4 method is obtained. It is to the best
understanding of the authors that this has not been
done by the aforementioned authors. The
subsequent parts of the article are sectionalized.
Section 2 involves the model formulation and
analysis and data fitting analysis. Section 3 involves
the numerical implementation of the model
equations by the use of SDM and RK4 methods,
while Section 4 discusses the results and conclusion.
See also a study in [34] as a case study of Lagos
State, Nigeria.
2 Model Formulation
The model is divided into the Susceptible;
Infected ; and Recovered , where the
whole human population yields
. ∏ denotes the crude birth
rate, β represents the transmission rate per COVID –
19 infective, ϕ is the recovery rate for COVID – 19
infection, κ is the mortality related to COVID – 19
infection and µ is the natural death rate. Using these
descriptions, the model is expressed as:
=
(1)
Analytically, Eq. (1) is positively invariant and
well posed in the region:
WSEAS TRANSACTIONS on BIOLOGY and BIOMEDICINE
DOI: 10.37394/23208.2024.21.7
Ogunlade Temitope Olu,
Ogunmiloro Oluwatayo Michael et al.