A leading researcher believes both the World Health Organisation and the New Zealand Government have got it wrong over the disease, which still kills more than 2 million people each year and has been targeted for elimination by 2050.
Prof Philip Hill believes the WHO's policies are flawed. He also considers New Zealand's policy on testing and treating Tb in immigrants is failing and that policy-makers do not properly understand the biology of Tb. Mark Price reports.
In Otago, you could be forgiven for thinking tuberculosis has been beaten - gone like smallpox.
Just four cases have been confirmed in the past two years and two cases are still awaiting results.
According to the Southern District Health Board, four of the Otago cases involved "overseas residents" and that tallies with a 2003 Ministry of Health statistic that 69% of Tb patients in New Zealand were foreign-born.
Prof Philip Hill, director of the University of Otago's Centre for International Health, has no issue with immigrants, but he does have an issue with the way New Zealand deals with those coming into the country who may be carrying the disease.
He believes policy-makers have got it wrong and a major part of the reason is they simply do not understand the term "biphasic".
In relation to Tb, biphasic means there are two opportunities for someone exposed to Tb to get the disease.
Having been coughed on by someone with Tb, about 5% of people will get the disease in the following year or two.
But another 5% of those coughed on can carry the dormant Tb bacillus for decades before suffering (activating) the symptoms of disease.
Prof Hill says New Zealand's Tb-screening programme for immigrants is not picking up this second group.
"They have an X-ray if they are positive (have been exposed to Tb) and then, if that's clear of disease, they send them into the community in New Zealand."
Eventually, Prof Hill says, a proportion of this group "start coughing up Tb in New Zealand that they got from overseas" - something that could be prevented using medicine at the early stage.
"It's just silly. It's like the biphasic thing is beyond the human ability to policy-make.
"They think of disease: you get exposed, you get disease or not. They don't think of the fact that actually, with Tb it's a biphasic thing, and we need to be thinking about it if we want to control Tb coming into the country.
"We need to be giving prophylactic (preventive) treatment to those who show evidence of infection from when they were overseas."
Prof Hill says most Tb in New Zealand comes from immigrants in whom the disease is activated after their initial screening.
"They're coughing over Kiwis and their own families, and they are perpetuating Tb as a problem.
"If you look at the graph of Tb in New Zealand over the last several decades, you have this lovely reduction and then this resistant low level. You won't eliminate Tb if you don't manage those guys."
While Tb can usually be treated, there is worldwide concern about the rise of Tb strains resistant to antibiotics.
Prof Hill believes the rise of these strains means New Zealand needs to be "very vigilant".
"It is dangerous to take Tb lightly at times when the number of cases is relatively low."
Prof Hill's research takes him to such places as Gambia in west Africa where Tb is rife.
But in his years of travelling, he has never been required to be tested for Tb on his return to New Zealand - even though he could be a carrier. This, he believes, is another example of a system designed to eliminate Tb not working properly.
And he believes the problem is a "basic misunderstanding of the biology".
He applies a similar criticism to WHO, which is this year spending $US4.1 billion ($NZ5.8 billion) promoting campaigns to stop Tb.
Its stated target is to eliminate Tb as a public health problem by 2050.
That target, according to the respected medical journal The Lancet, in May, "will not be met with present strategies and instruments".
And Prof Hill agrees because, among other reasons, WHO's strategy, called "directly observed therapy" or DOT, "ignored" carriers.
"You can actually give people who are exposed to a Tb case one drug for some months and that will have an up to 90% chance of stopping them developing Tb in the future."
Prof Hill perceives a "fundamental theoretical problem" with WHO's policy that makes it "pretty silly really".
"You have a strategy from WHO which is called 'passive case detection' based on diagnosing what we call smear-positive Tb using an old-fashioned microscope slide.
"The second problem is that the population in Africa has no idea about most diseases and processes, and it's pot-luck whether they will chose to turn up to a proper Tb diagnostic centre when they are coughing, because they've got no idea what the coughing means.
"So a passive case detection process, where you rely on them to turn up to you, is pretty silly really because that is the least-educated population with the highest burden [of disease]."
Prof Hill says WHO has "quite impressive figures" in some countries to show how well its strategy is being employed, "but it doesn't actually control the disease".
He likens it to measures put in place to stop the spread of swine flu in New Zealand after the first cases emerged.
"We had fantastic so-called screening at the airport ... in the meantime, swine flu is just flowing on through into the country.
"The latest suggestion is that a huge proportion of New Zealanders were exposed last year to swine flu while all these so-called successful control strategies at airports and so on were meeting all their requirements.
"It's actually a waste of time."
Asked to respond to Prof Hill's criticism, the Ministry of Health told the ODT this week new guidelines for the control of tuberculosis would be released "shortly".
These would provide "detailed and comprehensive" advice on all aspects of managing the disease.
"Also, for the first time a specific chapter on the diagnosis and treatment of latent tuberculosis infection is included.
"The updated guidelines identify the scenarios for when adults who are recent immigrants from high-incidence countries should be screened and considered for latent tuberculosis infection treatment."
The guidelines would "provide an opportunity" for raising awareness of Tb among health practitioners.
"For new patients from high incidence countries, they should be informed about: the need for early investigation of signs and symptoms of Tb; that Tb is a treatable disease; and that treatment of Tb in New Zealand is free."
The spread of Tb has been used by New Zealand First leader Winston Peters in arguments about immigration. However, Prof Hill says he has "no time" for Mr Peters' argument and New Zealand should provide a safe home for refugees.
"I personally find it repulsive to exclude them for any reason. We should take them with open arms with all their associated complications and treat them as our fellow human beings.
"We can manage their Tb, if they have it, with diagnostic tests and treatments that are cheap."
When approached by the ODT this week, Mr Peters, who has been accused of "immigrant bashing" said there had been "a veil of secrecy" over the issue of treating Tb in immigrants.
"The reaction I had was, from those who knew and sympathised, a quiet silence because they were too scared to put their heads up, and from the usual group of self-appointed nationwide conscience-holders the usual babble about this being racist."
He was not impressed that new guidelines from the Ministry of Health were imminent.
"That just represents an absolute abrogation of their responsibilities over two decades.
"To be putting out new guidelines now, since the influx of this sort of immigration in 1988, 22 years after the beginnings of this event, is frankly disgraceful.
"Between themselves and Immigration they have dramatically let this country down; though, to be fair, they have had ministers in charge of them who have just ignored it."
Tb symptoms
Symptoms of the various forms of tuberculosis can include:-
• Common cough with a progressive increase in production of mucus and coughing up blood
• Fever
• Loss of appetite
• Weight loss
• Night sweats
source: emedicinehealth.com