Re-emerging disease can be
defined as the reappearance of a known disease after a significant decline.
Examples of re-emerging disease are yellow fever, Dengue, Hemorrhagic disease,
Cholera (Banta, 2000). Tuberculosis is one of the oldest diseases that are
making a world wide come back. As early as 1993 the world health organization
(WHO) declared TB a ‘’global emergency” and medical experts feared that
tuberculosis may eventually become untreatable due to its high prevalence. Tuberculosis
is now the leading infectious killer of adults world wide causing 26 percent of
deaths in the developing world. In 1990,
four times as many people died from TB and according to the WHO, TB will kill
30 million this
decade while 300 million more will be infected (Delahauty,
2008).
In fact, more than one third of the world population
(approximately 2 billion people), is currently infected with the tubercle
bacillus. However, only 5-10 percent will display symptoms while the remaining
90-95 percent of people infected with bacillus will not suffer any ill-effects
as long as the infection remains inactive. But if their immune system is compromised
by many factors including malnutrition, chemotherapy, or AIDs or of if they
undergo severe stress, the bacillus can become active and a contagious
condition can result. The discovery of effective medications to combat
tuberculosis in the mid 1940s provided new hope for tuberculosis patients in
the industrial world who formerly could not withstand the disease thereby submitting
to the Sanitarium, life of bed rest, boredom, and often painful procedures.
However, the falling rate of tuberculosis has been halted or reversed in many
parts of the world.
Since 1987 the number of tuberculosis cases reported has
remained constant while different countries of the world are all experiencing a
resurgence of TB (Delhauty, 2008). There are a number of contributing factors
to the resurgence of TB in developed countries and they include:
1. Increased
migration: International travelling and tourism has
hastened the spread of TB from country to country where the disease is endemic.
In 1994 it was reported that a known woman suffering from TB infected some of
her fellow passengers during a flight from Chicago to Honolulu (Delhanty 2008).
Immigrants are more likely to live in poor and crowded conditions where the
disease is easily transmitted (Siege, 1998).
Number of international immigrants
has more than doubled tuberculosis infection in the last 35 years amounting up
to 175 million, where one in every 35 persons is an international immigrant. Screening immigrants for tuberculosis is
controversial as it is generating considerable media, political and public health
interest. Compulsory screening is common policy but has been criticized as being
in-effective, poor value, discriminatory, stigmatizing and divisive (Brewin et
al 2008).
2. Increased
evidence of AIDS:-
Because
people with weakened immune systems are
more susceptible to infection, tuberculosis is more likely to become active in
a person with AIDS where tuberculosis and AIDS coexist. TB is the leading cause of death among people
diagnosed with AIDS accounting for 40 percent fatalities world wide, and about
40 percent in African (Delahanty, 2008).
It was noted that an unusual
number of white middle class gay men were developing active tuberculosis as
might be predicted in a disease manifested by severe compromise of cellular
immunity. Persons with AIDS were highly susceptible to reactivation of latent
TB, and to the rapid development of severe tuberculosis after exposure to an
infectious case. (Schecter, 2001).
3. Emergence
of multidrug resistance: Over
the past two years researches have reported a growing number of cases of
multidrug – resistance (MDR) and extensively drug – resistance (XDR). Drug
resistance in tuberculosis has been noted since the interlocution of antibiotic
treatment. The drug resistance strains of the bacillus are spread by patients
who are not successfully cured by drugs, often because they do not complete the
course of treatment. The mortality rates from multidrug resistance strains are
comparable to those in the pre-antibiotic era (Delahanty, 2008).
4. Weakening
of public health care systems in both the developed and developing worlds: In New York City, the return of
tuberculosis coincided with the collapse of the city’s public health services.
The same may occur in any part of the
world, where free distribution of tuberculosis medication was stopped. In the
developing world, tuberculosis has remained endemic although the risk of
infection declined by 1-5 percent every year from mid 1930s to mid 1980s. Since
then however, this trend has reversed and national tuberculosis programme are
now documenting increasing rates of all form of tuberculosis. (Delahanty, 2008)
5. Homelessness,
substance abuse and poverty: These
social factors have been persistent contributors to tuberculosis resurgence for
as long as record has maintained in Africa (Schecter, 1998).
6. The
re-emergence of tuberculosis in Africa has been blamed on various other
problems such as:
a. Poor epidemic surveillance
b. Lack of medicine and medical
services
c. In-appropriate diagnosis due to
limited diagnostic knowledge and skill.
d. Improper treatment because of
lack of sufficient diagnosis.
e. Negligence of private
practioners
f. Lack of guiding policy regarding
the role of private practioners on the eradication, prevention and control of
tuberculosis.
g. Lack of community awareness of
the danger of tuberculosis and its spread (WHO/TB 1997). There are modern environmental
and demographic conditions that have been implicated in the resurgence of
tuberculosis these include:
a. Population growth and increase
urbanization and crowding.
b. Irrigation, deforestation and
reforestation projects that alter the habitats of diseases carrying insects and
animals.
c. Human behaviours such as intravenous
drug use and risky sexual behaviours
d. Increased human contact with tropical
rain forests and other wilderness habitats that are reservoirs for insects and
animals that harbor unknown infectious agents. (Harper, 2000).