The
burden of tuberculosis in South Africa
Dr
Bernard Fourie
MRC National Tuberculosis Research Programme, South Africa
Africa
and southern Africa
In
their 1997 reports on the tuberculosis epidemic and on anti-tuberculosis
drug resistance in the world, the WHO paints a bleak picture
of the global failure of health service providers to deal with
the burden of tuberculosis. In the 216 reporting member countries
of the WHO, representing a total population of 5,72 billion,
there were an estimated 7,4 million new cases of tuberculosis
in 1995. This represents a rate of 130 cases among every 100
000 persons.
In Africa
the case rate is 216 per 100 000. The 11 countries of the Southern
Africa subregion contribute approximately 275 000 cases every
year to the total case load in Africa. Almost half of these
come from South Africa. In an analysis of tuberculosis trends
and the impact of HIV infection on the situation in the subregion,
it is estimated that by 2001 the smear positive case rate would
have increased from 198 per 100 000 population for the region
as a whole, to 681 per 100 000 if tuberculosis control efforts
are not optimised. To aggravate the situation, 69% of these
cases would be directly attributable to HIV infection.1
A serious
complication of the tuberculosis problem in Southern Africa
has been the emergence of multi-drug resistant (MDR) strains
of the organism causing the disease. Patients infected with
MDR require prolonged chemotherapy with very expensive medication
which will at best cure only half of them. Such treatments cost
at least 100 times as much as the cost of curing an ordinary
tuberculosis patient infected with drug-sensitive bacteria.
Very few countries can afford this additional burden.
In order
to determine the magnitude of the MDR problem in Southern Africa,
and the implication for National Tuberculosis Programmes (NTP's),
surveys are being conducted in various countries as part of
the activities of the WHO/IUATLD Global Working Group on Tuberculosis
Drug Resistance Surveillance. So far, information is available
for four countries in southern Africa: Botswana, Lesotho, South
Africa, and Swaziland.
Results
confirmed that initial resistance to first-line drugs is relatively
low in southern Africa compared to some other regions in Africa
and Asia where the problem is up to 5 times more common. Resistance
rates range between 4% and 12% for isoniazid, and between 4%
and 7% for streptomycin. For rifampicin it is 1% and for ethambutol
1%; MDR is fortunately still low at 1%, indicating that resistance
strains are not commonly transmitted from person to person.
On the other hand, rates for acquired resistance, that is resistance
which has arisen in patients previously inadequately treated
for tuberculosis, are at least three times higher than in patients
not previously exposed to anti-TB medications. The high rates
of acquired resistance point to a failure of control programmes
to effectively manage case-holding and treatment adherence.
South
Africa
South
Africa is burdened by one of the worst tuberculosis epidemics
in the world, with disease rates more than double those observed
in other developing countries and up to 60 times higher than
those currently seen in the USA or Western Europe. The MRC estimated
that the country had an estimated 180 507 cases (55% reported)
in 1997, or 419 per 100 000 of the total population.Of these,
32,8% (73 679 cases) were probably infected with HIV. Although
South Africa has lagged behind other African countries in terms
of HIV incidence (probably because of geographical, social and
political barriers), the HIV epidemic has increased rapidly
and exponentially during the last 6 years.
The tuberculosis
problem in South Africa is largely a result of historical neglect
and poor management systems, compounded by the legacy of fragmented
health services. Prior to the introduction of the Tuberculosis
Register in 1995 cure rates were unknown, and consequently control
efforts could not challenge poor performance. The implication
of this failure is evident from the fact that in 1997 a cure
rate of only 54% could be recorded, with the consequence of
continued high rates of transmission in the country.
The impact
of TB/HIV-coinfection in provinces such as KwaZulu-Natal, Mpumalanga
and Gauteng, is leading to sharp increases in tuberculosis rates
in these areas. Over the next 5 years the epidemiological profile
of tuberculosis in South Africa is likely to change dramatically.
Increasing rates are likely to continue, and will be more pronounced
in provinces with fast-growing HIV infection rates. Optimal
tuberculosis control efforts with high cure rates and a significant
decline of more than 20% in the transmission of HIV infection
will be required before stabilisation and eventually a downward
turn in tuberculosis rates in the country might only become
visible towards the end of this period.
Estimates
by the MRC National Tuberculosis Programme indicate that current
trends in the epidemic will continue unless effective control
is achieved, resulting in 3,5 million new cases of tuberculosis
over the next decade and at least 90 000 patients dying.1 The
financial implications are staggering: Given that more than
US$100 million are spent annually on tuberculosis in South Africa,
in excess of US$3 billion would be required over the next 10
years if current increases in tuberculosis rates are allowed
to continue unabated. On the other hand, significant reductions
in transmission of HIV infection together with effective tuberculosis
control would mean a turn-around in the tuberculosis epidemic
by the year 2003. At least 1,7 million tuberculosis cases will
be prevented and more than US$400 million would be saved.
On the positive
side, however, tuberculosis was declared a top health priority
by the Department of Health in November 1996 and National Health
Minister Zuma committed her Department to implementing a new
control programme based on the DOTS strategy of the World Health
Organisation. The pace and extent of implementation of the programme
is, however, slow in most provinces. Since 1996, a system of
case registration based on strict criteria for case definition
was implemented in South Africa. These registrations, based
on standardised criteria, are now beginning to present a clearer
picture of disease rates in the country than what was available
before. Some progress is being made in certain provinces in
South Africa. Mpumalanga (despite relatively high HIV rates)
and the Western Cape are already showing dramatic improvements
in cure rates, because of disciplined implementation of the
DOTS strategy of the WHO in these provinces. Other provinces
are at various stages of implementation of the process .
In comparison
with the MRC estimates based on epidemiological modelling as
mentioned above, actual registration reports to the National
Department of Health indicated smear positive rates per province
(per 100 000 of the total population) of 285 for the Western
Cape, 300 for the Eastern Cape and 328 for the Northern Cape.
All other provinces had rates below 200. The overall rate for
South Africa was 163 for smear positive and 310 for all pulmonary
tuberculosis cases.2 It suggests that the country might be in
a slightly better situation than what had been estimated as
the worst scenario. Also, it appears that the epi-centre of
tuberculosis in South Africa is shifting away from the Western
Cape, which had until recently been regarded as one of the regions
with the highest tuberculosis rates in the world. Several factors
might be responsible for this shift, including improved case-finding
in the Eastern and Northern Cape, and/or more effective control
procedures in the Western Cape.
Although
the overall situation in South Africa still seems to be far
less than optimal, these early signs of improvement could signal
the beginning of better times for tuberculosis control in the
country.
References
-
Fourie PB, Weyer K. Epidemiology. In: WHO review of the tuberculosis
situation in South Africa. Geneva: WHO, July 1996.
-
Fourie PB, Donald PR. Epidemiology of tuberculosis. In: Donald
PR, Fourie PB, Grange JM (eds). Tuberculosis in Childhood.
Pretoria: Van Schaik's Publishers, 1999.
SADC
Countries
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