* Pluralistic approach drives new ways of improving health
* Particular progress in infant, child, maternal mortality
* But major challenges of poverty and malnutrition remain
By Kate Kelland, Health and Science Correspondent
LONDON, Nov 21 (Reuters)- Bangladesh has had 40 years of exceptional progress in health, with infant mortality down, life expectancy up and good disease control, all despite being one of the world's poorest countries, researchers said on Thursday.
Most often in the news for its poverty or natural or manmade disasters, such as a factory fire that killed 1,129 people in April, Bangladesh was described in studies published on Thursday as a "remarkable success story" and one of the "great mysteries of global health".
"Over the past 40 years, Bangladesh has outperformed its Asian neighbours, convincingly defying the expert view that reducing poverty and increasing health resources are the key drivers of better population health," said Professor Mushtaque Chowdhury from Dhaka's BRAC University, who co-led a series of studies published in The Lancet medical journal.
The rate of women dying in childbirth has dropped by 75 percent since 1980 in Bangladesh, while infant mortality has more than halved since 1990. Life expectancy has increased to 68.3 years - surpassing neighbouring India, at around 67 years, and Pakistan at around 66 years.
Chowdhury's team said that although Bangladesh has low health spending, its health system allows private and public sectors and non-governmental organisations to work together.
This has led to rapid improvements in access to essential services such as diarrhoea treatment, family planning, vitamin A supplementation and vaccination coverage, they said.
An example of health success is in tackling tuberculosis (TB) - an infectious and difficult-to-treat disease with which India has been fighting a largely unsuccessful battle for many years.
The researchers found that through mass deployment of community health workers, TB cure rates rose from less than 50 percent to above 90 percent - among the highest in the world.
To boost contraceptive use, Bangladesh recruited female health workers to deliver door-to-door family planning services and achieved high (62 percent) contraceptive prevalence and a rapid fall in fertility from 6.3 births per woman in 1971 to 2.3 in 2010 - rates unparalleled in similar nearby countries, the researchers said.
Pakistan's contraceptive use, for example, is around 35 percent and its fertility rate is 3.8 births per woman.
"Promoting an open culture of research-based innovation has made Bangladesh a pioneer in scaling up community-based approaches," said Abbas Bhuiya, a professor at Dhaka's International Centre for Diarrhoeal Disease Research, co-leader of the study series.
But the researchers said poverty and newer problems that come with rapid urbanisation, such as an upsurge in chronic and non-communicable diseases and increasing vulnerability to climate change, cast a shadow over the successes.
"The stark reality is that prevalence of malnutrition in Bangladesh is among the highest in the world. Nearly half of children have chronic malnutrition. Moreover, over a third the population (more than 47 million) live below the poverty line, and income inequality is widening," said Bhuiya.
More also needs to be done to address a poorly-equipped public health sector which, although free to the poor, faces an estimated shortage of 800,000 doctors and nurses, the researchers said. (Editing by Robin Pomeroy)