Aids empowers an old and deadly enemy: A potentially catastrophic chapter in the history of TB is unfolding. Neil McKenna reports on the HIV factor

THERE are probably more cases of TB in the world now than in 1882, the year Robert Koch, the German scientist, isolated mycobacterium tuberculosis. Despite sophisticated drug regimes, vaccines and TB-control programmes, the disease has continued its deadly progression.

Tuberculosis flourishes wherever there is poverty, malnutrition, overcrowding and inadequate health care. The statistics make grim reading: globally, 1.72 billion people - or one-third of the world's population - are latently infected with TB. At any one time, between 9 million and 11 million people are suffering from active TB, 95 per cent of them in Asia, Africa, and Latin America.

Each year, TB claims nearly 3 million lives. Half a million children from the developing world die from it annually. The tragic irony is that TB is preventable and, in most cases, curable.

Now, a new, potentially catastrophic chapter in the history of tuberculosis is unfolding. The established epidemic of TB and the new epidemic of HIV have shown a disturbing tendency to coalesce and to co-infect individuals. It is a dangerous liaison both for those who are co-infected and for those communities in the developing world at risk of TB.

Unlike HIV, which is overwhelmingly transmitted through sexual intercourse, TB is highly infectious and casually contagious. TB can be spread by coughing. And while the spread of HIV can be mitigated and controlled through education and safer sex, it is hard to see what measures can halt TB's relentless spread.

The World Health Organisation (WHO) estimates that 4.5 million people, 98 per cent of them in the developing world, are co-infected with HIV and TB. This is almost certainly an underestimate. There are signs, too, of a growing problem in the developed world.

The implications are grave. Dr Paul Nunn, of London's School of Hygiene and Tropical Medicine, says the risk groups for both epidemics overlap in many countries in the developing world. People with HIV are more likely to develop active TB. And HIV-positive people suffering from active TB are three to four times more likely to die than HIV-negative people with active TB.

It is the speed with which the TB epidemic is accelerating in the developing world that most worries the WHO and experts such as Dr Nunn. Since 1987, the rates of people known to have TB in many sub-Saharan African countries have risen sharply. Tanzania, Burundi and Malawi all report huge increases in the number of cases of active TB. In Uganda, confirmed cases doubled between 1984 and 1987, and in Zambia the Ministry of Health said the number of cases had risen from 7,000 in 1986 to 17,000 in 1990.

According to Dr Jan Andersson, a specialist working in Zambia, this increase is mainly due to the rising incidence of HIV. The WHO estimates that around 60 per cent of TB patients in Uganda and Zambia are infected with HIV. In Africa, TB has already become the prime cause of death in adults with HIV.

The devastating potential of this twin epidemic in Africa was demonstrated when Canadian and French researchers used mathematical models to try to estimate its impact on sub-Saharan Africa. In their most optimistic prediction, assuming a low risk of TB infection and low HIV prevalence rates, the researchers calculated that the number of cases of active TB in the 15-49 age group will increase by two-thirds by the turn of the century.

Their most pessimistic forecasts suggested a 12-fold increase in the cases of active TB by the year 2000. Applied to the population of Kampala, this would mean 2 per cent of the city's population of half a million would develop active TB every year.

The study draws some grim conclusions: 'It appears that HIV infection is, as it were, pushing the epidemiological clock back towards the time of the first encounter of human populations with tubercle bacilli.' It warns that there is every reason to expect the increase in the number of tuberculosis cases to continue well into the 21st century.

TB chemoprophylaxis, administering anti-TB drugs to HIV-positive people to prevent the onset of active TB, could save thousands, perhaps tens of thousands, of lives and simultaneously help limit the spread of the epidemic. But the cost is enormous. The WHO has been conducting a study in Uganda on the feasibility of mass chemoprophylaxis but 'the preliminary results suggest a lot of difficulties'.

'Africa needs more and better TB diagnostic services, more and better anti-TB drugs, more hospital beds, and other services and supplies,' says Dr Mario Raviglione of the WHO's TB programme. 'Developed countries need to provide - must provide - more money to target intervention and control programmes in developing countries and to buy drugs and equipment.'

Although TB has not become a real problem in the developed world, there are disturbing portents. In June, the WHO announced that TB has been rising in nine out of 14 European countries. Much of the increase was attributed to immigration, but a number of cases seem to be linked to HIV, especially in southern Europe. TB infection rates among people with HIV are as high as 10 per cent in Spain and Italy.

In the United States, TB has been rising significantly since 1986. The emergence of multi-drug-resistant TB (MDR-TB) in the past 18 months has been greeted with alarm bordering on panic. MDR-TB appears to infect people with HIV and Aids almost exclusively and has so far resulted in a mortality rate of around 80 per cent. MDR-TB has brought calls for draconian measures from the Centers for Disease Control in Atlanta. It wants patients with TB to undergo 'directly observed therapy', which in effect means court-ordered, involuntary detention for the duration of treatment.

Larry Gostin of the American Society of Law and Medicine claims there have already been 'hundreds' of cases of involuntary detention of patients with TB in New York's inner-city hospitals, and says 'patients have been confined to their rooms, sometimes tied to their beds'.

Despite the gravity of the situation worldwide, doctors and epidemiologists are most anxious about the potential spread of HIV/TB co-infection in Asia, where around two-thirds of the world's TB-infected population is concentrated. 'If HIV starts spreading rapidly in India and Thailand, as it seems to be doing, we will have many, many more cases of active TB to deal with,' Dr Raviglione says.

Dr Ishwar Gilada, secretary and founder of the Indian Health Association, believes the seeds of a public health disaster have already been sown: 'In 1988/89 a survey at a hospital in Bombay found that 2 per cent of TB patients were also infected with HIV. This figure has increased to about 10-15 per cent in the past two years. I have very little hope for the year 2000. India is heading for a major health catastrophe.'

Time is running out all over the world. The WHO has called the epidemics 'an immediate and grave public health and socio-economic threat, particularly in the developing world'.

Neil McKenna is editor of 'WorldAIDS' magazine, published by the Panos Institute.

(Photographs omitted)

Start your day with The Independent, sign up for daily news emails
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Assistant Exhibition Content Developer

£19000 per annum: Recruitment Genius: Based in South Kensington, this prestigi...

Recruitment Genius: Office Administrator

£16000 - £20000 per annum: Recruitment Genius: Established managed services IT...

Recruitment Genius: Customer Service Advisor

£15000 - £16000 per annum: Recruitment Genius: A Customer Service Advisor is r...

Recruitment Genius: Plant Fitter - Construction Industry

Negotiable: Recruitment Genius: This well established construction equipment d...

Day In a Page

The difference between America and Israel? There isn’t one

The difference between America and Israel? There isn’t one

Netanyahu knows he can get away with anything in America, says Robert Fisk
Families clubbing together to build their own affordable accommodation

Do It Yourself approach to securing a new house

Community land trusts marking a new trend for taking the initiative away from developers
Head of WWF UK: We didn’t send Cameron to the Arctic to see green ideas freeze

David Nussbaum: We didn’t send Cameron to the Arctic to see green ideas freeze

The head of WWF UK remains sanguine despite the Government’s failure to live up to its pledges on the environment
Author Kazuo Ishiguro on being inspired by shoot-outs and samurai

Author Kazuo Ishiguro on being inspired by shoot-outs and samurai

Set in a mythologised 5th-century Britain, ‘The Buried Giant’ is a strange beast
With money, corruption and drugs, this monk fears Buddhism in Thailand is a ‘poisoned fruit’

Money, corruption and drugs

The monk who fears Buddhism in Thailand is a ‘poisoned fruit’
America's first slavery museum established at Django Unchained plantation - 150 years after slavery outlawed

150 years after it was outlawed...

... America's first slavery museum is established in Louisiana
Kelly Clarkson: How I snubbed Simon Cowell and become a Grammy-winning superstar

Kelly Clarkson: How I snubbed Simon Cowell and become a Grammy-winning superstar

The first 'American Idol' winner on how she manages to remain her own woman – Jane Austen fascination and all
Tony Oursler on exploring our uneasy relationship with technology with his new show

You won't believe your eyes

Tony Oursler's new show explores our uneasy relationship with technology. He's one of a growing number of artists with that preoccupation
Ian Herbert: Peter Moores must go. He should never have been brought back to fail again

Moores must go. He should never have been brought back to fail again

The England coach leaves players to find solutions - which makes you wonder where he adds value, says Ian Herbert
War with Isis: Fears that the looming battle for Mosul will unleash 'a million refugees'

The battle for Mosul will unleash 'a million refugees'

Aid agencies prepare for vast exodus following planned Iraqi offensive against the Isis-held city, reports Patrick Cockburn
Yvette Cooper: We can't lose the election. There's too much on the line

Yvette Cooper: We can't lose the election. There's too much on the line

The shadow Home Secretary on fighting radical Islam, protecting children, and why anyone in Labour who's thinking beyond May must 'sort themselves out'
A bad week for the Greens: Leader Natalie Bennett's 'car crash' radio interview is followed by Brighton council's failure to set a budget due to infighting

It's not easy being Green

After a bad week in which its leader had a public meltdown and its only city council couldn't agree on a budget vote, what next for the alternative party? It's over to Caroline Lucas to find out
Gorillas nearly missed: BBC producers didn't want to broadcast Sir David Attenborough's famed Rwandan encounter

Gorillas nearly missed

BBC producers didn't want to broadcast Sir David Attenborough's famed Rwandan encounter
Downton Abbey effect sees impoverished Italian nobles inspired to open their doors to paying guests for up to €650 a night

The Downton Abbey effect

Impoverished Italian nobles are opening their doors to paying guests, inspired by the TV drama
China's wild panda numbers have increased by 17% since 2003, new census reveals

China's wild panda numbers on the up

New census reveals 17% since 2003