Afghanistan, one of just four countries in the world where polio is endemic, has seen the number of people suffering from the disease surge this year. There have been 29 confirmed polio cases in 2006, compared to only nine cases last year, according to the WHO in Kabul.

"This is a massive campaign and involves 34,000 volunteers administering drops of polio vaccine to 7.2 million children across the country," UNAMA spokesman Adrian Edwards said in Kabul.

Many new polio cases recorded this year have been in southern Afghanistan, which is experiencing a deadly phase of Taliban-led violence. Officials say the deteriorating security situation in the south, which has hampered polio immunisation drives, has been the leading cause of an increase in the disease in the impoverished country.

"One of the most important aims of the campaign is to curtail the polio virus in southern Afghanistan and minimise the risk of it spreading to other parts of the country," Dr Tahir Mir, medical officer for polio vaccination at the WHO, told IRIN.

During the September and August polio vaccination drives, about 75,000 children were missed out in the southern region and about 50,000 children were not immunised in the Karabagh, Nawa, and Gilan districts of southeastern province of Ghazni due to security problems, according to the WHO.

Unregulated travel to and from Pakistan, where polio still exists, difficulty in establishing health services, a lack of awareness and poor communication with community leaders were the main factors fuelling polio's spread in the impoverished Central Asian state, health officials said.

Polio is a highly infectious virus that invades the nervous system and can cause total paralysis in hours. It can strike at any age, but mainly affects children under five. It enters the human body through the mouth and multiplies in the intestine. Besides Afghanistan, polio remains endemic in Nigeria, India and Pakistan.

After years of denying that AIDS was a problem, Chinese leaders have dramatically shifted gears in recent years, promising anonymous testing, free treatment for the poor and a ban on discrimination against people with the virus.

President Hu Jintao signalled the new approach by appearing on national television in late 2004 chatting and shaking hands with AIDS patients.

Rehnstrom said reported HIV cases have been steadily increasing at a rate of about 30 per cent annually since 1999, but the real number of HIV cases in China is likely four to five times the reported figure.

The UN said Tuesday in its annual report on the epidemic that an estimated 39.5 million people are now living with the AIDS virus worldwide as infection rates and deaths from the disease continue to mount.

The reported number of cases in China grew to 183,733 by Oct. 31 this year, up about 28 per cent from 144,089 at the end of last year, the Health Ministry said in a report posted on its website. Of the reported cases, 40,667 have developed into AIDS, it said.

Expand clean needle, methadone programs: UNAIDS

"Each new HIV infection is a tragedy," Rehnstrom said. "The government needs to focus its efforts on ... trying to stop the spread of HIV and trying to bring the spread of HIV under control as soon as possible by controlling HIV transmission among injecting drug users and sex workers."

He said government efforts to promote clean needles and methadone treatments were beginning to have an effect but that those programs needed to be expanded.

The official Xinhua News Agency reported Wednesday that government health surveys show that only about 39 per cent of Chinese sex workers use condoms and about 51 per cent of drug addicts still share needles.

The report also quoted Hao Yang, deputy director of the Health Ministry's Bureau of Disease Control, as saying that the rising number of cases showed that "the danger of the disease spreading further remains great."

The ministry said in its report that 37 per cent of the cases reported this year were linked to drug use and 28 per cent were caused by unsafe sex.

About five per cent of the cases were caused by people selling blood illegally or receiving infected blood from hospitals.

Tainted blood source of China's outbreak

HIV gained a foothold in China largely because of unsanitary blood plasma buying schemes and tainted transfusions in hospitals. China has cracked down harshly on such schemes and declared last year that the problem of tainted blood supplies was under control though new cases still emerge sporadically, often in rural areas.

Transmission from mothers to babies was about one per cent, the ministry said. It did not say what caused the remaining infections.

Experts say China has hundreds of thousands of people infected with HIV who don't know it or choose not to report it. At the end of last year, China and the UN estimated there was a total of 650,000 HIV cases in the country, including those that were unreported.

The ministry said Wednesday there had been 4,060 AIDS deaths this year as of Oct. 31, bringing the total number of reported deaths in China from the disease to 12,464 since it was identified there in the mid-1990s.

Medicinal uses of weakened forms of the toxin include smoothing facial wrinkles.

A nearly two-year investigation by researchers at the U.S. Centers for Disease Control found the effects of the injections received by the four patients were long lasting, with one patient staying on a mechanical ventilator for 171 days.

All four are still feeling the effects today, Dr. Daniel Chertow of the CDC in Atlanta and his colleagues report in Wednesday's issue of the JAMA (Journal of the American Medical Association).

The patients were given botulism toxin A that was clearly labelled for research purposes only.

Use only licensed products: authors

"Physicians and patients must be aware of the hazards associated with illegitimate use of unlicensed botulinum toxin products. Only licensed products should be used clinically," the study's authors wrote.

"Entities inappropriately marketing, selling, or using unlicensed botulinum toxin products should be sought and subjected to full criminal and civil penalties."

A doctor in Florida was sentenced to three years in jail for using an unapproved drug in relation to the cases of the four patients.

A 100-microgram vial of the toxin that was given to the patients had enough botulism in it to kill more than 14,000 people.