A team of scientists, led by S. K. Kar at the Rajendra Memorial Research Institute of Medical Sciences in Patna, has found that plastering a smooth layer of mud and lime on the walls of buildings deprives the sandfly Phlebotomus argentipes of the moist dark crevices where it likes to breed. The lime also helps to kill the fly’s larvae.

The parasite transmitted by the sandfly’s bite causes fever, enlargement of the spleen, liver and lymph nodes. Untreated, the disease is generally fatal.

During the late 1950s, India began a campaign of spraying homes with DDT to eradicate malaria. The spray killed the sandflies as well as the mosquitoes and the incidence of leishmaniasis fell dramatically. By the 1970s, however, the sandflies had become resistant to insecticides and the disease reappeared. In 1990, more than 600 people in India died from leishmaniasis.

The team from Patna tested its mud plaster in the village of Badhwar. The dank cattle sheds were ideal breeding places for the sandfly. The scientists counted sandflies by shining a torch into the sheds. When flies appeared they were sucked into a jar.

First, they counted the number of flies in May when the fly population is near its peak. In September, the team returned to plaster the test sheds, first with mud, then with a mixture of lime and water. By next May, the fly count in the treated sheds had dropped by more than 90 per cent. Kar says that the more careful the plastering the more effective it is. The team recommends regular replastering so that cracks in the plaster do not create fresh breeding sites.

Most estimates come not from counting the animals but by taking impressions of paw marks, a notoriously inaccurate method. Now Ullas Karanth, a zoologist with the Wildlife Conservation Society of New York, will carry out a census with a technique that not only counts the number of tigers, but can also distinguish between individuals.

Karanth fixes two cameras on either side of a tiger trail and sets up an infrared beam, similar to those used in burglar alarms. When a tiger walks along the track it breaks the beam and triggers the cameras, which take a picture of the beast. The project is being sponsored by the society, the US Fish and Wildlife Service and India’s environment ministry.

A team from the Central Forensic Science Laboratory, which investigated the blasts, blames a build-up of methane in the sewerage system. The explosions were felt over an area of about 3.5 square kilometres. Some of the injured were thrown 5 metres into the air, and the force of the blast cracked large areas of concrete and tarmac. Fires started in several places underground.

The forensic team said the drainage system was blocked in places. They believe that this is what led to a massive build-up of methane.

A government-appointed committee asked to report on the explosions said that the blasts could have been caused by a highly flammable mixture of methane and petroleum vapour, which could have leaked into the drains from petrol stations. The panel blamed poor maintenance of Delhi’s old sewerage system – and also recommended a ban on plastic bags, which helped to clog up the drains.

The tiger protocol grew out of the Global Tiger Forum held a year ago in Delhi, where the Indian authorities said they were worried that the flourishing market for traditional Chinese medicines based on tiger bones, blood and organs, was eroding India’s tiger population. India argued that as China has no tigers of its own, supplies must come from poachers working in India. India later approached the Chinese government to make the case for a joint effort to ensure the survival of the tiger.

The protocol includes plans to establish joint research and training programmes, and an exchange of data to improve wildlife management. Both countries will begin with campaigns to try to stop the trade.

In the past year, the Indian authorities have made large hauls of tiger skins and bones and uncovered a number of poaching networks. A single tiger can fetch as much as $60 000 in the illegal markets of the Far East. “It has been felt by the Indian government that unless the Chinese government takes steps to curb the demand in their country, the Indian tiger population will continue to decline rapidly,” says a spokesman for the Ministry for Environment and Forests.

Mahendra Vyas, a lawyer in Delhi’s Supreme Court, and a wildlife enthusiast, explains that the main aim of such political agreements is “to keep the tiger in focus”. The reality, he says, “is that there is still a great demand for tiger preparations and this is fuelling a huge clandestine trade”.

With the help of a native species of deep-burrowing worm, Pheretima elongata, the Green Cross Society of Bombay a nonprofit-making organisation that provides “vermiculture services”, has begun a large number of projects to convert rubbish into useful compost. The worms, introduced into a pit or container of garbage, eat their way through it to produce a fine, friable compost.

Although vermiculture is a tried and tested process, the outbreak of plague has sent orders soaring. Shantu Shenai, who runs the Green Cross Society, says that orders have increased 25-fold, coming from organisations as varied as housing societies, factories and government bodies such as the railways.

Shenai, who learnt the techniques of vermiculture at the Bhawalkar Research Institute in the neighbouring city of Pune, says he is “just doing what nature would naturally do”. The institute, run by Uday and Vidula Bhawalkar, sells worm stock for vermiculture schemes worldwide. Now its worm technology could help to clean up rubbish closer to home.

Bombay generates 5800 tonnes of rubbish a day. According to Shenai, the Green Cross Society has made a “modest beginning”, processing 4 tonnes of slaughter-house waste every day. And with help from Shenai’s group, the Bombay Municipal Corporation will soon be processing 20 tonnes of vegetable waste a day in Kalyan, north of Bombay. The city authorities, who rely on incinerators and landfill, have begun to show some interest in the potential of the worms.

At the XVI International Cancer Congress in Delhi last week, Michael
Blaese, head of the Clinical Gene Therapy Branch at the US National Institutes
of Health in Bethesda, Maryland, described the preliminary findings of the
trial. The results are “so promising”, he said, that the team will move on to
a larger trial.

Blaese stressed that it is still too early to get excited. “I do not want
to mislead people by saying this is the magic bullet that is going to cure
brain cancer, but I do hope this will be another tool that will be effective
in cancer treatment.”

The gene therapy is designed to destroy tumour cells while leaving healthy
brain cells untouched. The brain tumour is injected with a mouse retrovirus
that has been engineered to carry a gene from the herpes simplex virus, which
infects only dividing cells. Tumour cells divide rapidly, but healthy brain
cells do not divide at all.

The herpes gene instructs the cell to produce the enzyme thymidine kinase,
which makes the cell susceptible to the antiherpes drug ganciclovir. After
treatment with the virus, patients are given ganciclovir, which destroys cells
that produce thymidine kinase.

Jan Stjernsward, head of the Cancer Care and Palliative Unit of the WHO in
Geneva, told the conference that developing nations must improve their general
education so that people can learn how to avoid risks linked with cancer. He
said their governments should control tobacco, preferably by law.

“Appropriate technology and low-capital training programmes” would be the
most effective ways of reducing the incidence of cancer in the poorer
countries of the world, Stjernsward said.

The WHO is overseeing cancer control programmes in a large number of
developing countries, including Zimbabwe, India, Malaysia, Thailand and Oman.
Each country has to work out its priorities in dealing with cancer, and
outline a strategy for prevention and treatment. The WHO’s role is to guide
these national programmes.

Stjernsward highlighted the many obstacles these countries face if they are
to make any progress against cancer. “India, for instance, has failed against
the tobacco barons,” he said. “Tobacco must be made unaffordable.” Another
problem in India is the concentration of cancer specialists in a few cities.
“These are inaccessible to the majority of India’s cancer patients.”

Screening could help to combat the disease. Tony Miller, professor of
medicine at the University of Toronto, said that with early detection the
number of deaths from cancer worldwide could be cut by 40 per cent.

“India has done a lot of pioneering work in developing cost-effective
approaches to cancer,” said Stjernsward. Screening can significantly reduce
deaths from cancers of the mouth and cervix. In both cases the tests are
simple and cheap.

But screening programmes are of little use unless people are aware of the
risks of cancer and are prepared to go for checkups. Kerala in India, and
Catalonia in Spain provide good examples of what education and the empowerment
of women can do. In Kerala, the incidence of all cancers has fallen sharply as
the area has achieved 100 per cent literacy. “The same methods can be used
successfully all over the developing world,” said Stjernsward.

He also stressed the need to look at cancer prevention in a social context.
“Many of the improvements in the field of cancer are not because of technical
advances but political commitment,” he said. “This is like the tuberculosis
story, where mortality was reduced not so much by discovery of the bacillus,
vaccination and good treatment, but by achieving social objectives like better
housing and less crowding.”

Shiv Dhyan Singh, of the Crop Protection Division of the International
Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has tested the
rather smelly treatment in greenhouses and in field trials. He says the spray
is almost “100 per cent effective” in preventing infestation with the fungus
Glaviceps sorghi, which causes ergot.

Ergot is “one of the most devastating diseases of sorghum. It can wipe out
entire crops,” says Duncan McDonald, who heads ICRISAT’s Asia Centre. Sorghum
is grown on around 44 million hectares worldwide, with an annual production of
about 58 million tonnes. According to McDonald, plant breeders have had little
success in trying to create varieties of sorghum that can resist the
fungus.

The fungus infects the flower spikelets, making them secrete a sweet sticky
substance. The honeydew attracts insects, which spread the fungus from plant
to plant. Ergot is also spread during threshing, which breaks open the fungal
spore cases.

“This is groundbreaking research – the development of an environment-
friendly control measure of a disease for which there is no known resistance
in the host plant,” says Singh.

The spray protects the crop from infection rather than curing the disease.
Its advantages are its simplicity and safety, and the fact that farmers can
buy the raw material cheaply in the local market. Singh expects to market a
commercial version of the spray. The pesticidal properties of allicin, the
active ingredient of garlic, are well known. The researchers at ICRISAT have
shown that the treatment does not interfere with pollination or seed
production. “The garlic fungicide is nearly 100 per cent effective if used
prior to infection in the post-rainy season,” says McDonald. The most popular
chemical fungicide, mancozeb, is at best 75 per cent effective, he says.

The only drawback to treating crops with a solution of garlic is that rain
washes it away. Singh hopes to improve the spray by adding a component to make
the garlic stick to the plant. He is also trying to find a quicker and easier
way of processing large quantities of garlic cloves. The team at ICRISAT is
also testing how effective garlic is at protecting other crops.

Even though cancers account for a relatively small share of all disease in
developing countries, the actual number of cases is greater than in the
industrialised world because of the larger populations, says Indraneel Mittra,
an oncologist at the Tata Memorial Centre (TMC) in Bombay. Of 4.3 million
deaths each year worldwide from cancer, about 70 per cent are in the
developing world. Breast cancer and lung cancer are becoming more common in
most populations worldwide.

Mittra was speaking at the XVI International Cancer Congress in Delhi this
week. He said screening methods suited to local conditions must be developed.
“We need to create cheap, simple and good methods for breast examination
instead of relying on the much more expensive mammography.”

The TMC is developing a project in Bombay to train health workers to check
more than 70 000 women a year for breast cancer. “It needs to be understood
that there is a basic difference between cancer control in the West and in
Asia,” says Mittra. “The large and market-driven economies of the West may
never allow such simple procedures a fair try.”

Meanwhile, hundreds of delegates were ordered not to travel to India by
their governments because of fears of plague and malaria. Of the 5000
expected, almost a fifth cancelled their reservations.

Ram Ratan Yadav and Amalav Bhatt-acharya of the Birbal Sahni Institute
of Palaeobotany in Lucknow have found distinct differences in the annual
growth rings of pines from the western Himalayas before and after a quake
in 1991. In October that year, an earthquake registering 6.2 on the Richter
scale hit the hills of Uttarkashi in northern India, killing more than a
thousand people.

The two palaeobotanists studied cores from 12 pines. Annual growth rings
form as wood is laid down during the growing season and the width of each
year’s ring reflects the conditions that year. In a good year, for example,
a tree generally produces more wood than in a year of drought. The tree
ring study showed that an earthquake can also influence growth.

Between 1991 and 1992 there was an abrupt halt in the growth of the
pines, and the ring for 1992 was very narrow compared with previous years.
The effect was not visible until 1992 because the quake struck at the end
of the previous year’s growing season, say the researchers.

Strong seismic shocks can severely damage trees, tearing up their roots
from the soil. In such cases, trees cannot take up water or nutrients efficiently
– stunting their growth.