CHAPTER ONE
1.0 INTRODUCTION
1.1 Background of the study
Microsporidia are single-celled,
obligate intracellular parasites that were recently reclassified from
protozoa to fungi. Microsporidia are a group of intracellular parasites
which have attracted the interest of parasitologists for over 100
years. The first species, Nosemabombycis, was discovered in the
middle of the 19th century as the cause of silkworm disease (i.e.,
pepper disease, pebrine disease), which nearly destroyed the silkworm
industry in Southern Europe (Didier,2005; Franzen,2008).More than 1,400
microsporidian species have been described in both invertebrate and
vertebrate hosts. Only eight genera and 15 species of microsporidia have
been associated with human infections.
The first report on human microsporidia
infection was in 1959 and described the case of a 9-year-old Japanese
boy who presented with disseminated microsporidiosis associated with
fever, headache, vomiting,and spastic convulsions, (Matsubayashet al.,1959).
Interest in this group of parasites started with the development of the
AIDS pandemic around the world in 1980’s. In 1985, a new species Enterocytozoonbieneusiwas
found in an HIV-infected patient. Since then,species of microsporidia
have been recognized worldwideas etiologic agents of opportunistic
infections. The clinicalcourse of microsporidiosis depends on the immune
statusof the patient and the site of infection. The groups at
riskconstitute people with HIV/AIDS, organ transplant recipientsbeing
treated with immunosuppressive drugs, travellers,children and the
elderly, (Didier, 2000; Garcia, 2002;Rabodonirina, 2003; Wichro, 2005;
Dworkin, 2007; Galvan, 2011).
Two microsporodiaEnterocytozoonbieneusi and Encephalitozoonintestinalis have been identified as possible causes of diarrhoeal illness in HIV-infected patients, (Mouraet al.,1993;
Kotler, 1995).Over 40 million people are living with HIV/AIDS, the
majority (more than 25 million) of whom live in sub-Saharan Africa. Up
to 2.4 million deaths were recorded worldwide in 2005, (Akinboet al.,2009).
People in the advanced stages of HIV
infection are vulnerable to secondary infections and malignancies that
are generally termed as opportunistic infections as they take the
advantage of the opportunity offered by a weakened immune system,
(Saidu, et al.,2009). In HIV/AIDS positive patients, the most
clinical manifestation is chronic diarrhoea and wasting due to enteric
infection, (UNIADS 1998).This parasite is commonly observed in
HIV-infected patients with CD4 Lymphocytes count of less than 50cells/mm3
who complain of chronic diarrhoea, nausea, malabsorption and severe
weight loss but asymptomatic infection have also been reported in
immunocompetentpersons,(Sak et al.,2011).
1.2 Justification
Microsporidiosisis a neglected tropical
disease that is associated with chronic diarrhoea especially in persons
living with HIV/AIDS, and in other immune-compromised individuals
(elderly, organ transplant individuals, travellers). In developing
countries like Nigeria, there has not been any serious efforts toward
the eradication of Microsporidiosis. Infection rate of Microsporodiosis
is on the increase in tropical and subtropical countries due to lack of
health hygiene, access to public health centres, and knowledge of the
disease. In Nigeria detection of microsporidia is not routinely
performed in clinical practice, there is therefore dearth of information
concerning Microsporidia in respect to prevalence, diagnosis, treatment
and control.
Few cases of the disease has been
reported in HIV/AIDS, and other immune-compromised individuals in
Nigeria. However, epidemiology and prevalence of the disease has not
been well documented for sustainable control. There is therefore a need
for further study and understanding of the epidemiology of the parasite.
Documenting the prevalence of the Infection will aid in management and
control of the disease.
1.3 Aim
This study is aimed at assessing the prevalence of Microsporidia in HIV/AIDSpatients in Minna, Niger State.
1.4 Objectives
The specific objectives of this study are to determine:
- The prevalence of Intestinal Microsporidia among HIV/AIDS patients of General Hospital Minna, Niger State.
- The species of Microsporidiainvolved in relation to sex and age among HIV/AIDs patients of General Hospital Minna, Niger State
- The association of CD4 Cell count and Microsporidia infection in HIV / AIDS patients.