SUMMARY

Introduction: Transmission of infectious diseases is still a major global public health burden and Cameroon is among the leading countries suffering from the burden of infectious diseases. This study is aimed at modeling contact pattern of the population, identifying factors associated with population contacts and simulating spread of infectious diseases using COVID-19 as an example in the Buea health District.

Methods: A community based cross sectional study design will be used to collect data from inhabitants of Buea Health District. Participants that will take part in this study will be individuals of 18 years and above who have stayed in Buea Health District for at least three months. Four health areas within Buea Health District will be selected using simple random sampling technique (two semi-urban and two rural health areas) and data will be collected using a questionnaire. Data collected will be analyzed on SPSS version 25 using a poison logistic regression model to determine factors associated with population contacts. Excel will be used to draw the graph of prevalence of contact pattern. A compartment model (Susceptible(S), Exposed(E), Infectious(I), Recovery(R) or Dead(D) and Susceptible(S) (SEIRS)) for COVID-19 pandemic will be build using data collected from the Region Delegation of Public Health Buea.

Expected outcome: Determine the extent to which one individual can spread an infectious disease like COVID. Determine contact patterns among the Buea Health District population.

Keywords: Statistical modeling, Disease transmission, Infectious disease, Social contacts,

CHAPTER ONE
 INTRODUCTION
1.1 BACKGOUND

Infectious diseases are responsible for about one quarter of deaths worldwide, causing at least 10 million deaths per year, mainly in the tropical countries since the beginning of the 21st century[1,2]. Emerging infectious diseases are a high burden on public health and have an impact on global economies. Their origin is generally connected to social and economic conditions as well as environmental and ecologic factors .

The rapidly growing of global interconnectedness has led to the increased occurrence of emerging or reemerging infectious diseases with the potential to spread rapidly and affect populations across international borders.  Infectious diseases are responsible for an immense global burden of disease that impacts public health systems and economies worldwide, disproportionately affecting vulnerable populations.  The World Health Organization (WHO) estimates that approximately one third (20 million) of the annual deaths worldwide are attributed to infectious diseases.

In 2013, infectious diseases resulted in over 45 million years of lives lost due to disability and over 9 million deaths[4]. This has created the need for global solutions such as the International Health Regulations (IHR) adopted in 2005. The IHR (2005) aims to proactively develop public health systems that can prevent the spread of infectious disease and provide better containment mechanisms[5]. Infectious diseases continue to burden populations around the world. Both naturally occurring and intentionally introduced biological threats hold increasing potential to cause disease, disability, and death[6]

Africa faces a double burden of infectious diseases and its account for at least 69% of deaths on the continent[7]. Many African health systems are under-funded and under-resourced and struggle to cope with the cumulative burden of infectious diseases[7], and an estimated 80% of regional health budgets has been allocated to infectious disease for the last decade. According to WHO, African region is characterized by the largest infectious disease burden and the weakest public health infrastructures , thus posing a threat to global health security[9].

In the WHO African region, the 2014–2016 Ebola virus disease (EVD) outbreak in West Africa highlighted the significance of reducing the vulnerability of communities to threats of infectious diseases that spread across national borders [10]. The late detection of this epidemic revealed the weaknesses of the disease surveillance systems in several African countries[11]. Since then, the WHO regional office for Africa has increased its efforts in supporting Member States to rapidly detect public health events (PHE) of international concern and rapidly implement effective public health actions. This has being done through the implementation of the integrated disease surveillance and response (IDSR) strategy by ministries of health [12] and the establishment of an epidemic intelligence unit at the WHO regional office.

In Cameroon, infectious diseases are amongst the most commonly notified diseases and largest cause of mortality.  Also in Cameroon, major infectious diseases associated with a high degree of risk within the population include food or waterborne diseases (bacterial and protozoal diarrhea, hepatitis A and E, and typhoid fever), vector borne diseases (malaria and yellow fever), water contact disease (schistosomiasis), respiratory disease (meningococcal meningitis), and animal contact disease (rabies)[13].

Cameroon is a low-income country with a rapidly increasing population, which was estimated at 28.2 million people in 2022[14]. The country is undergoing social and economic changes, which are resulting in increased urbanization with a potentially negative impact on health-related behaviors as result of this the country is experiencing a double burden of infectious disease. Taking example of COVID-19 the country registered nearly 90,000 confirmed cases with 1,357 deaths in September 2021[15].

Infectious diseases have been a constant threat to humanity. This threat has been intensified in the past few decades due to the emergence and re-emergence of several fatal infectious diseases [16]. In 2019, the World Health Organization (WHO) has released the top ten health threats for mankind for the coming decade. The list included several items related to infectious diseases such as Ebola, malaria, Zika, and Acquired Immunodeficiency Syndrome (AIDS) [17]. In late 2019, the Coronavirus disease (COVID-19) was identified in Wuhan, China, and has spread worldwide, leading to an ongoing pandemic killing hundreds of thousands of people [18].

In 1927, Kermack and McKendrick proposed the SIR (Susceptible-Infected-Recovered) compartmental model for the first time in order to study the epidemic law of the Black Death prevailing in Europe at that time. On the basis of the SIR model’s analysis, the “threshold theory” was proposed to distinguish the spread or regression of the disease. The validity of the SIR model has been proven by the data regarding large-scale infectious diseases in history, thus the deterministic model  based on a differential equation has been widely accepted[19]. Mathematical approaches have been widely utilized for modeling the spread of the infectious diseases.

For example, compartmental models, including susceptible– infectious (SI), susceptible–infectious–susceptible (SIS) and susceptible–infectious– recovered (SIR) models, characterize the spread of an epidemic over time in a population of agents who pass through the states like “Susceptible”, “Infectious” and “Removed” (recovered or dead)[20]. Little has been done on infectious disease modeling in Cameroon as a whole and the Buea health district in particular. This study aims to determine contacts pattern of population in the Buea health district, identify factors associated with population contacts and model population contact and spread of infectious diseases using Covid-19 as an example in the Buea health district;

1.2 STATEMENT OF THE PROBLEM