CHAPTER ONE
1.0    INTRODUCTION
1.1    Background of Study
A mushroom (or toadstool) is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi (Basidiomycota, Agaricomycetes) that have a stem (stipe), a cap (pileus), and gills (lamellae, sing. lamella) on the underside of the cap (Smith et al., 2015). "Mushroom" also describes a variety of other gilled fungi, with or without stems, therefore the term is used to describe the fleshy fruiting bodies of some Ascomycota. These gills produce microscopic spores that help the fungus spread across the ground or its occupant surface.
Forms deviating from the standard morphology usually have more specific names, such as "bolete", "puffball", "stinkhorn", and "morel", and gilled mushrooms themselves are often called "agarics" in reference to their similarity to Agaricus or their order Agaricales. By extension, the term "mushroom" can also designate the entire fungus when in culture; the thallus (called a mycelium) of species forming the fruiting bodies called mushrooms; or the species itself (Smith et al., 2015).
Mushrooms are well known all over the world and the edible ones have been considered as functional foods. They serve to enrich food as supplements and they provide health benefits beyond the traditional nutrients they contain (Smith et al., 2015).
1.2    Statement of the Problem
Globally, millions of deaths attributed to malaria are being recorded. The disease constitutes a huge epidemiologic burden in Africa and continues and continues to cripple the economic development in the region (Trudell and Ammirati, 2009). In Nigeria, the disease is responsible for 60% outpatient visits to health facilities, 30% childhood death, 25% of death in children under one year and 11% maternal death (Philips, 2011). The financial loss due to malaria annually is estimated to be about 132 billion Naira in form of treatment costs, prevention, loss of man-hour, etc.; yet, it is a treatable and completely evitable disease (Philips, 2011). Malaria is endemic in Nigeria with 97% of the population of 170 million living in areas of high malaria risk and an estimated 3% living in malaria free highlands. Nigeria bears up to 25% of the malarial disease burden in Africa, making this country with the highest malaria mortality (WHO, 2014).
The Global Fund (TGF)’s response in the fight against malaria in Nigeria is co-managed by the National Malaria Elimination Programme (NMEP). Currently NMEP is implementing New Funding Model (NFM) of TGF which began in January 2015 (WHO, 2014). Implementation of malaria control interventions is broad-based and includes: Case Management; Integrated Vector Management; Special Interventions such as Intermittent Presumptive treatment with Sulphadoxine and Pyrimethamine; and other supportive interventions (WHO, 2014).
Edible mushrooms have been source of food to man, even before the for-knowledge of its nutritional content. It has served as major source of food in several African countries including Nigeria (Smith et al., 2015). However, its use as an antimalarial agent has not been documented. There is therefore, the need to assess the suppressive effect of the extract of this mushroom on albino mice.
1.3    Justification of the Research
Although the parasite responsible for P. falciparum malaria has been in existence for 50,000–100,000 years, the population size of the parasite did not increase until about 10,000 years ago, concurrently with advances in agriculture (Harper et al., 2011) and the development of human settlements. Close relatives of the human malaria parasites remain common in chimpanzees. Some evidence suggests that the P. falciparum malaria may have originated in gorillas (Prugnolle et al., 2011). References to the unique periodic fevers of malaria are found throughout recorded history (Cox, 2013). The advent of multiple drug resisitant malaria led to the continuous effort to curb the menace it has created through the use of all possible approaches for its eradication. However, P. berghei is used as a model organism for the investigation of human malaria because of its similarity to the Plasmodium species which cause human malaria. P. berghei has a very similar life-cycle to the species that infect humans, and it causes disease in mice which has signs similar to those seen in human malaria. Importantly, P. berghei can be genetically manipulated more easily than the species which infect humans, making it a useful model for research into Plasmodium genetics.
In several aspects the pathology caused by P. berghei in mice differs from malaria caused by P. falciparum in humans. In particular, while death from P. falciparum malaria in humans is most frequently caused by the accumulation of red blood cells in the blood vessels of the brain, it is unclear to what extent this occurs in mice infected with P. berghei (Craig et al., 2012). Instead, in P. berghei infection, mice are found to have an accumulation of immune cells in brain blood vessels (Craig et al., 2012). This has led some to question the use of P. berghei infections in mice as an appropriate model of cerebral malaria in humans (Craig et al., 2012).
Although the decreased sensitivity of malaria parasites to an antimalarial drug was first reported about a century ago in association with quinine, the term drug-resistant malaria was rarely used; resistance was not considered a major problem until the late 1950s, after chloroquine resistance emerged. Historically, chloroquine was widely used as the standard first-line drug against P. falciparum. Resistance was first detected on the Thailand–Cambodia and the Venezuela–Colombia borders, near areas where chloroquinated salt was used for malaria control, forcing the affected countries to begin switching to sulfadoxine–pyrimethamine (SP) in the 1970s. Resistance to SP developed quickly, again on the Thailand–Cambodia border. The spread of chloroquine and SP resistance to other parts of Asia and as far as Africa is well documented (Plowe, 2009). Several articles have been published on the use of various extracts with antiplasmodial properties to eradicate Plasmodium falciparum from the blood stream of induced albino mice. Hence, a need for further review of the work to ascertain the effects of these compounds with antiplasmodial activities.