Re-evaluation of the Existence of Mycobacterium Tuberculosis using Microscopicf, Sputum Staining Examination

TABLE OF CONTENTS

Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

Appendice

References

Objective: To assess the case of mycobacterium tuberculosis (M.TB) infection in the province of Porto Novo, Cape Verde.

Limitations of the test: Radiological, antigen detection, and bacteriological culture of sputum were not possible.

Keywords: Microscopy, AFB, Ziehl Neelsen, Mycobacterium Tuberculosis

ABSTRACT

A total of 256 sputum samples, were stained using Ziehl Neelsen method, in Medical Laboratory section of Hospital of Porto Novo, between 3rd of July, 2008 to 30th of April, 2012. A total of 16 (6.25%) of the samples were positive for mycobacterium tuberculosis, while 240 (93.75%) were negative. Males (n=131) showed higher infectivity 14 (10.68%) than females (n=125) that recorded 2 (1.6%).This research concluded that, free and appropriate treatment for all the infected persons, improving laboratory diagnostic facilities, and further research, to include, cultural and antigen detection assay were the areas that needed immediate attention.

Keywords: Microscopy, AFB, Ziehl Neelsen, Mycobacterium Tuberculosis

INTRODUCTION

Mycobacterium tuberculosis causes tuberculosis which kills more people than any other infectious disease. In 1993, because of the serious public health threat posed by tuberculosis, the World Health Organization (WHO) declared it a global emergency. Since then, the incidence of the disease has continued to rise with over 7 million people developing tuberculosis each year, and around 3 million dying from it. The people mostly infected were adults and children in developing countries, specifically Southeast Asian, sub-Sahara Africa, Latin America, and western Pacific ,(WHO 1998).

Factors contributing to the resurgence of tuberculosis in developing countries, and problems in its control include; co-infection with HIV (most important factor), emergence of multi-drug resistivity, inadequate treatment, continuing poverty, malnutrition, overcrowding, armed conflict and increasing numbers of displaced persons. Infection with HIV greatly increases the risk of developing tuberculosis, and accelerates its progress. Progression to AIDS is also accelerated in those co-infected, and HIV has a significant effect on the risk of relapse of tuberculosis. WHO estimates that tuberculosis causes up to 40 % of AIDS deaths in Africa and Southeast Asian.

Most infections with M. Tuberculosis are caused by inhaling cough droplets or dust particles containing tubercle bacilli which become lodged in the lungs, forming a small inflammatory lesion. Bacilli also infect adjacent lymph nodes. Activated macrophages form a granuloma around the site of primary infection which usually limits it. In most people, the primary lesion is self healing, although, not all the bacilli may be destroyed, (some remain dormant in lymph nodes and may reactivate causing post- primary disease). There may be fibrous scarring and sometimes calcification of the healed area.

The WHO again in 2009, estimated, that 9.4 million new cases of TB have been documented and 1.7 million people have been killed by the dreaded disease. The vast majority of patients live in low and middle income countries where TB diagnosis depends primarily on direct smear microscopy of sputum. Microscopy has low sensitivity and does not detect smear negative TB, which may account for 24% to 61% of all pulmonary cases in HIV infected people, Dr. Andy Ramsay (2011).

In 1998, 65% of patients attending Tebellong Hospital in Lesotho- Southern Africa were diagnosed with TB, and from then to date, the incidence of pulmonary TB never ceased to rise, as a result of the increased incidence of HIV infection, and the number of TB cases is expected to increase in a parallel fashion, Tebellong Hospital report, (1998).

Re-infection was attributed also as causing the increase in a country at several levels, Viedman DG et al (2002). The work of Dr. Webb EA et al (2009), reported high prevalence of TB disease in diabetic children and adolescents in Western Cape Province of South Africa. In a highly endemic country with high BCG vaccination coverage in Africa, TB infection in children who were in contact with individuals with infectious TB was directly related to the intensity of exposure of the children to the person with TB, Lienhardt C et al (2003).

Acquisition of TB in health care facilities is a well documented and recognized hazard for healthcare providers and visiting patients. Dental practitioners may be at increased risk because they work in close contact to potentially infectious secretions, Harlow RF & Rutkauskas JS (1995). The risk increases where TB is endemic and control practices are poor, and compliance with guidelines for preventing TB in healthcare facilities, such as those issued by the Centre for Disease Control (CDC) is limited.

Both environmental and host factors are responsible for the transmission and prevalence of different M. Tuberculosis strains. Because TB has no detectable horizontal gene transfer, Hirsh AE et al (2004). But, large sequence polymorphisms can be used as phlogenetic markers to trace the evolutionary relationships of different strain families, Warren RM (2003).

In 2010, the CDC, Atlanta alerted that 9 million people around the world have became sick due to infection of TB and that about 1.5 million others have died from the TB pandemic disease worldwide. According to the CDC report, TB continued to assume a leader in killing massively and brutally those infected with HIV.

In women aged 15 to 44 years, in developing countries, tuberculosis is the third most common cause of morbidity and mortality combined, and TB kills more women than any other infectious agents including, malaria and AIDS, Murray et al (1990). Case- notification rates from countries with high prevalence of TB suggests that tuberculosis (TB) may be less frequent in females than males. Globally, the ratio of female to male tuberculosis cases notified to WHO every year is 1/1.5 to 2.1 cases, and 70% more smear positive males than females are diagnosed yearly, Diwan & Thorson (1999).

It is unclear why more males than females are diagnosed with tuberculosis, but epidemiological information, shows that there are differences between men and women in prevalence of infection, rate of progression from infection to disease, incidence of clinical disease, and mortality due to tuberculosis, Holmes CB et al (1998).

Although, the tuberculin- testing prevalence studies indicate that more males than females are infected with tuberculosis, alternative explications for these findings is that there are differences in the immune response to tuberculin. This theory was supported by a study from Japan showing that more males than females are infected of tuberculosis, using positive tuberculin reaction as standard, Kurasawa T (1990).

The experimental work of Dr. Shaaben MA et al (1990) proved that boys had a delayed- type hypersensitivity reaction to more Mycobacterium tuberculosis sensitins than girls as well as larger scars after BCG revaccination. Differences between females and males in immune response could thus, be part of the explanation of differences in symptoms, signs, forms and outcomes of tuberculosis.

However, both males and females are infected, progress to disease and die due to tuberculosis. Whereas males and females share many beliefs and attitudes to tuberculosis, there are considerable differences with regard to stigma and its negative consequences, which are harsher for the female family members. Stigma may lead to delays for both sexes in seeking care, but more so for females if the physical, geographical, and economic accesses to health care is limited. The social structure of many societies in developing countries today relies on women having a double or triple workload responsibilities of caring of the family and home, doing agricultural work and perhaps also doing waged or paid work. Therefore, the impact of TB in women is thus devastating and/or severe not only on their families, but also on the development of the society through loss of workforce, ruined families, and orphaned children.

Tuberculosis control is a gender matter that has been so long neglected by the tuberculosis control agencies or programs. Gender in a sense not only refers to the physiological differences between sexes, but also to the variety of behaviours, expectations, and roles that exist within a social, economic, political and cultural context.

A gender based approach to TB control will assist in understanding not only the biological and cultural differences between the sexes, but also the structural violence leading to poverty, grossly inadequate healthcare resources and increased risk of tuberculosis and death.

The prison population has a higher incidence of TB, than the outside world because of the risk factors of infection and developing tuberculosis of those entering prison and the special characteristic of closed institutions, particularly overcrowding. The work of Dr. Vicente Martin Sanchez et al (2000) reported high incidence of TB in Spanish prison population in Leon, Spain, with cases of TB of 6.39 cases per 1000 prisoners and this value is 14 times superior than that estimated for the Leon, Spanish, general population.

The US department of health (2009) estimated that more than one-third of the world´s population has TB bacterium in their systems, which means that they have TB infection. In addition, new infections are occurring at the rate of one per second. Fortunately, only a fraction of people infected with TB develops active TB disease. Those who do not get sick are known to have non- contagious latent TB, so – called because the bacteria are inactive in the body. TB bacteria can remain in this dormant condition for months, years and even decades without virulence multiplication. Most people with this kind of infectivity will always test positive on the tuberculin skin test or chest X-ray. This diagnosis indicated that these people have TB bacteria in their bodies and at the same time may not develop active form of the disease.

Furthermore, one in ten people infected with the TB bacteria; do develop active form of TB disease. Hence, it becomes obvious to treat appropriately both the latent and active TB diseases.

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