PREVALENCE OF SALMONELLA AND ASSOCIATED RISK FACTORS AMONG PATIENTS ATTENDING BUEA REGIONAL HOSPITAL

ABSTRACT

Salmonella disease has remained a significant public health challenge in developing countries including Cameroon. The aim of this study was to determine the prevalence of Salmonella infection among patients attending Buea Regional Hospital. A total of 112 stool samples were obtained from both male and female patients using wide mouthed screw cap containers. The stool samples were inoculated into Selenite F Broth overnight and later cultured on Salmonella-Shigella agar (SSA) medium for the isolation of the causative agent. From the stool culture, 12 out of the 112 samples showed the characteristic presence of Salmonella giving a prevalence ot 10.7%. Flic gender distribution showed that the prevalence was higher in female patients 8(12.5%) than the male patients 4(8.3%) The infection was highest in the age group of 31-50 years (17.6%) while the lowest was observed in the age group more than 50 years (9.1%) with no infection observed among patients less than 5 years of age. Use of flushing toilets (83.3%) or use of municipal tap water (83.3%) and contacts with pets such as dogs (80.0%) or the handling of poultry and poultrv products (100%) were important risk factors among the positive patients. These findings highlight the need of reinforcement of hygiene promotion especially among those who prepare food and municipal water supply and intensification of environmental interventions.

CHAPTER ONE

INTRODUCTION

• Background to the Study

Salmonella infection is a common global cause of enteric fever such as typhoid, a disease responsible for about 20 million episodes of illness and over 200,000 deaths annually globally (Jin and Pollard. 2017). Typhoid, which is a disease caused by Salmonella typhi, is an acute illness characterized by high fever, malaise, a self-limiting diarrhoea, nausea, chills, headache, bradycardia, hepatosplenomegally, delirium, psychosis, focal neurological deficit, septicaemia, bowel perforation and even death (Klochko and Wallace, 2018). Salmonella species causes systemic infection during which the pathogen colonizes the intestine and mesenteric lymph node, the liver, spleen, bone marrow and gall bladder (Parry and Dougan, 2020).

Salmonella was first discovered from pigs in 1880 by Daniel Elmer Salmon, an American veterinary pathologist and Theobald Smith. In 1890. the organism was named after D.E. Salmon to honour him (Ziprin, 2014). During the course of treatment of a typhoid outbreak in a local village in 1838. English country doctor William Budd realized that there were “poisons” in the infectious disease of the people and this poison was multiplying in their intestines and also were present in the excretions and could be transmitted to healthy individuals through their consumption of contaminated water (Pollack, 2013). He further proposed strict isolation or quarantine as a method of containing the outbreak in the future. The medical and scientific community did not identify the role of microorganisms in infectious diseases until the work of Robert Koch, Daniel Elmer Salmon. Karl Erberth and Eouis Pasteur which resulted to the discovery and isolation of Salmonella bacteria; named after D. E Salmon (Pollack, 2013).

Acuno- Soto el al., (2012) wrote about a pair of epidemics strucked the Mexican highlands in 1545 and 1576. causing an estimated 7 to 17 million deaths in the sixteenth and the seventeenth centuries. Later a study published in 2018 revealed that the cause of the epidemic was typhoid fever (Hersher, 2018). Some historians believe that the English colony of Jamestown, Virginia, died out from typhoid. Typhoid fever killed more than 6.000 settlers in the new world between 1607 and 1624. In the nineteenth century, the ninth and twelfth US presidents were believed to have died from typhoid infection due to the poor sanitary conditions in Washington DC in the mid- 19^lh century (Mcl 1 ugh, 2014). Mary Mallon (also known as Typhoid Mary) in 1907 became the first most notorious carrier of typhoid fever in the United States to be identified and traced. She

was a cook in New York and was closely associated with 53 cases and 3 deaths.

fntcric fever caused by Salmonella species affects only humans (who are the reservoir) and is spread through consumption of contaminated food and drink handled by people who shed the organism from stool or, less commonly, urine (Reddy el a!., 2011). It may also be acquired from ingesting water contaminated with sewage. Food needs to be heavily contaminated for infection to occur- approximately 10³ to 10⁹ cells may be required to cause illness (Reddy et al., 2011).

Diarrheal disease continues to be an important cause of morbidity and mortality in developing countries and globally, intestinal parasites, and Salmonella species remain major contributors to acute enteric infections (Ishaleku et al., 2015). Worldwide, enteric fever is most prevalent in impoverished areas that are overcrowded with poor access to sanitation. Incidence estimates suggest that south-central Asia. Southeast Asia, and southern Africa are regions with high incidence of Salmonella species infection (more than 100 cases per 100,000 person-years) (Buckle el al.. 2012; GBD, 2017). Other regions of Asia and Africa, some parts of Latin America, the Caribbean, and Oceania have a medium incidence of 10 to 100 cases per 100,000 person-years. These estimates, though, arc limited by lack of’consistent reporting from all areas of the world and arc based on extrapolation of data across regions and age groups. More recent population-based studies from Latin America, in particular, are lacking, and surveillance suggests that rates have declined substantially over the past 30 years.

Furthermore, subsequent data from Africa have revealed substantial heterogeneity between countries, with some Southern and Northern African countries having very low’ rates (<5 cases per

• person-years) while several countries in Lastcrn and West Africa have rates >100 per
• (Marks el al.. 2017).

fntcric infections like Salmonella species are widespread diseases affecting the population in Cameroon (Crump and Mint/.. 2010) with prevalences reported to range between 6 and 39 (Ndip et a/.. 2015; Awung el al.. 2018; Warn el al.. 2019). Poor personal and environmental hygiene, waste disposal as w’ell as consumption of food sold by unhygienic commercial vendors have been implicated as major factors that encourage stable transmission (Crump and Mintz, 2010).

Although, with adequate treatment, most patients recover from the acute phase of the Salmonella

infection. Some Salmonella species can persist asymptomatically within the gall bladder and

2

enteric following clinical recovery. Overall, 10% of those infected will carry Salmonella species within their gall bladder for up to 3 months, while 1 to 3% will continue to harbour it for longer than 1 year in the enterics (Gal-Mor el at. 2014).

• Statement of the Problem

The prevalence of Salmonella disease has been on an increase in Cameroon. This was shown in a cross-sectional study that was carried out by Nsutebu et at (2013) to determine the prevalence of typhoid fever in 200 consecutive patients with fever and symptoms clinically compatible with Salmonella fever to verify recent estimates of a high prevalence of Salmonella disease fever in Cameroon. Salmonella disease was confirmed in 2.5%. This trend tends to increase when Ndip el al (2015) found the prevalence of Salmonella infection in South West Cameroon to be 6.75% which showed a recognizable high endemicity rate. Meanwhile, Awung el al (2018) found an increased prevalence of 9.8% in the same South West Cameroon.

Since this disease leads to a lot of deaths, morbidity and usually predisposition to other diseases like gastrointestinal ulceration (Ray-Offor and Elenwo, 2015), it has therefore become necessary to explore the occurrence of Salmonella species infection and its associated risk factors among patients leading to an effective public health management and control.

• Research Questions

1. What is the prevalence of Salmonella infection among patients attending the Buea Regional hospital?
2. What is the prevalence of Salmonella infection in relation to gender and age among patients attending the Buea Regional hospital?

• What is the distribution of Salmonella infection across the risk factors among patients attending the Buea Regional hospital?