Asia's overall prevalence rate is much lower than that of sub-Saharan Africa, but India and China both have large caseloads.

The Joint U.N. Programme on HIV/AIDS (UNAIDS) says the epidemic is changing in some countries, and governments need to scale up their responses rapidly to prevent a serious crisis in several places including Pakistan, Indonesia and Vietnam.

In Bangladesh, like China, new HIV infections are increasing steadily, albeit at a slower pace than they were previously.

While the number of people living with HIV in Asia in 2007 remained stable (around 5 million), this is most likely due to the number of new infections (380,000) being equal to the number who died due to AIDS-related diseases.

Across most of the region the virus is still predominantly spread among intravenous drug users and their partners, and sex workers and their clients and partners. Men who have sex with men is an under-researched but potentially significant factor as well.

As in other regions, women are increasingly at risk of infection from their partners. In India, 90 percent of women with HIV said they were virgins when they married and had remained faithful to their husbands, according to this UNFPA State of World Population 2005 report. In Cambodia, 42 percent of all new HIV infections occurred from transmission by husbands to their wives. A third of new infections were to the babies of these women.

Ignorance about AIDS and social stigma surrounding the disease and those in high risk groups are also important driving forces behind the pandemic, says a 2006 World Bank report on South Asia.

But the good news is that many countries in South Asia still have a very low infection rate - including Sri Lanka, which has low infection rates even among high risk groups, according to the World Bank. And even where the epidemic is severe, it can still be contained, the report's authors say.

India is one of the top producers of cheap generic anti-retroviral drugs in the world. (For more on this see the main AIDS section.)

The number of people receiving anti-retroviral therapy has increased significantly in recent years, reaching over 400,000 in 2007, according to the 2008 UNAIDS Report, which cites figures from this joint report from WHO, UNAIDS and UNICEF. This still only represents about a quarter of people in need of anti-retroviral treatment in Asia and is lower than the global average of 31 percent. But it is a significant jump from 2006 when the figure was 280,000.

According to UNAIDS, much of the recent increase is down to improvements in Thailand - where more than 60 per cent of people in need of the drugs are now getting them - and in China.

Thailand has been widely praised for its work in containing the virus. The number of new infections fell from a peak of around 140,000 a year in 1991, to 18,000 in 2005, according to UNAIDS. This remarkable achievement came about mainly because men used condoms more, and also reduced their use of brothels.

However the U.N. Development Programme (UNDP) says there is mounting evidence that HIV is now spreading largely among the spouses and partners of clients of sex workers and among marginalised sections of the population, such as injecting drug users and migrants.

The 2008 UNAIDS report says the disease has become more heterogeneous and is increasingly affecting people traditionally considered to be at lower risk. About 43 percent of new infections in 2005 were among women, most of whom got the disease from husbands or partners.

Infection between men who have sex with men also appears to be on the rise. In Bangkok, HIV prevalence among this group rose from 17 percent in 2003 to 28 percent in 2005, and it is estimated as many as one in five HIV infections in Thailand in 2005 were attributable to unprotected sex between men.

There is some vagueness about figures in India.

UNAIDS/WHO figures for 2005 estimated India had 5.7 million people living with HIV/AIDS. But government estimates in 2007 put the figure at 2.47 million. UNAIDS subsequently said this figure was probably more accurate and now estimates the number at 2.4 million.

However, AIDS activists have cautioned in the past that many people in rural areas may not know their status, while deaths due to AIDS are often ascribed to other diseases like tuberculosis.

AIDS officials in India say one of the biggest problems they face is combating misconceptions about how the virus is spread in a nation where open talk of sex is often frowned on.

These misconceptions abound even among India's lawmakers. A 2006 survey of 250 MPs in India's lower and upper houses of parliament showed 56 percent thought a person could catch the HIV virus by sharing food and utensils with an infected person. And 40 percent thought working with an infected person was enough to catch the virus.

A 2006 report by the World Bank on AIDS in South Asia points out that India's epidemic is just as advanced in many rural areas as in urban populations. Yet almost all prevention programmes focus on cities and towns.

In recognition of this, the government launched a plan in August 2006 to involve tens of thousands of rural politicians in the fight against HIV/AIDS.

The sex industry is the main factor behind the spread of HIV in most of India - but this is not confined to mega-cities like Mumbai. For example, in one region of southern Karnataka state up to half the villages have at least 10 prostitutes working in them.

Compared with India, Nepal has a far lower but rising number of HIV cases and the World Bank has cited the trafficking of Nepalese women and girls as a risk factor for HIV transmission in the region.

According to UNAIDS, HIV prevalence among sex-trafficked females who have been repatriated to Nepal is at 38%, while up to half of those trafficked to Mumbai, who have been tested were HIV-positive.

At the moment India is focusing its HIV education initiatives on migrant workers and truckers, targeting them at haulage stops. The report says India should gear more anti-AIDS programmes towards sex workers.

The picture is a little different in India's northeastern states where intravenous drug use is behind the epidemic's rapid growth. However an increasing number of women, many the widows of drug users who have died from HIV/AIDS, are turning to sex work - a pattern that will likely accelerate the disease's spread.

The World Bank study says there's also evidence that the role that high risk homosexual activity and gay prostitution plays in spreading HIV in India is greater than previously thought.

Amid all this dismal reading there is a small glimmer of hope. Research suggests HIV prevalence may be declining in some southern states. The drop is attributed to a big rise in condom use among men going to sex workers.

CHINA

A production line at the Human-Care Latex Corporation, one of China's largest condom producers, 2006.
REUTERS/Jason Lee

In China, an estimated 700,000 people were living with HIV/AIDS in 2007, according to the 2008 UNAIDS Report.

However, the UNDP warns that this figure could jump to 10 million people by 2010 unless effective action is taken now.

Injecting drug use is driving the epidemic in some areas, including Xinjiang in the west and Guangdong in the south. In other areas, such as Anhui, Henan, and Shandong, HIV gained a foothold in the early 1990s among rural people who were selling blood to supplement their meagre farm incomes.

UNAIDS estimates that men who have sex with men represents up to 7 percent of HIV infections in China.

There have been innovative attempts to try and address ignorance about AIDS. Beijing launched its first officially sanctioned gay chat room in 2006, hosted by Chaoyang district's disease prevention centre.

Until relatively recently homosexuality was considered a mental disorder. And one Beijing-wide survey cited in a 2005 U.N. report found that 85 percent of homosexual men interviewed did not realise they could catch HIV/AIDS.

Slightly fewer than half of people living with HIV in China are believed to have been infected while injecting drugs, according to the latest UNAIDS report. China has established scores of needle and syringe exchange projects and hundreds of clinics for drug users.

This jungle-clad, mountainous nation faces one of the fastest growing HIV/AIDS epidemics.

PNG's Health Minister Peter Barter has said that the practice of polygamy in the country is a major obstacle in the fight against the disease. Another problem is the lack of doctors. The World Bank said in 2007 that the country only had 284 doctors - and half worked overseas.

Some 54,000 people are living with the virus, according to the 2008 UNAIDS report.

But AIDS workers have estimated in the past that under-reporting and reluctance to be tested mean the real number ranges from 80,000 to 120,000.

The UNAIDS report said HIV was the leading cause of hospital admissions and deaths in the country, with HIV positive patients occupying 70 percent of beds at Port Moresby General Hospital.