Trying to measure the impact of the Zimbabwean exodus on HIV/AIDS rates in the region is so fraught with ifs, buts and maybes that the only reasonable assumption is that, like other migrants, economic migrants may run a higher risk of infection than they would have if they had not left their homes.

The scale of Zimbabwean migration to neighbouring states is disputed, with estimates ranging from more than three million people to a few hundred thousand, making an overall assessment of the actual spike in transference of the disease, if any, in the region difficult to assess, but it is accepted that the act of migration tends to increase HIV/AIDS infections.

The Southern African Migration Project (SAMP), a non-governmental organisation researching regional migration issues, found that migration was one of many social factors contributing to the sub-continent's HIV/AIDS pandemic.

In a 2004 research paper, Migration, Sexuality, and the Spread of HIV/AIDS in Rural South Africa, SAMP commented: "previous studies have shown that people who are more mobile, or who have recently changed residence, tend to be at higher risk of HIV infection than people in more stable living arrangements.

"In Uganda, for example, people who have moved within the last five years are three times more likely to be infected with HIV than those who have lived in the same place for more than 10 years," the researchers said.

"In a South African study, people who had recently changed their residence were three times more likely to be infected with HIV than those who had not. It is not so much movement per se, but the social and economic conditions that characterise migration processes that puts people at risk for HIV."

Gang rape

Zimbabwe's economic meltdown is seen as the main driver of the upswing in undocumented migrancy to neighbouring states. The country is in the throes of a recession that has already lasted for seven years, shortages of basic commodities, fuel and electricity are commonplace, the official inflation rate has topped 7,000 percent - the highest in the world - and unemployment is at 80 percent.

In the first quarter of 2008, more than a third of the population is expected to face severe food shortages, according to international aid agencies.

Undocumented Zimbabwean migrants travelling to neighbouring South Africa or Botswana, the preferred destinations of the majority because of the size of their economies and their proximity, risk contracting HIV even before arriving.

Nick van der Vyver, programme officer at the Reception and Support Centre of the International Organisation for Migration (IOM) in Beitbridge, the Zimbabwean town nearest the border with South Africa, told IRIN/PlusNews that "irregular migration has served as a magnet for illegal migration, with seriously organised and nasty gangs operating within the first 10km of the border [in South Africa]."

Known as as the "magumaguma" (scavengers), the gangs ferry undocumented migrants across the border for a fee, said to be about R1,500 (US$140), and often rob and rape those who have paid them for their "service"; other illegal migrants crossing the border independently are often ambushed by the gangs.

Since the IOM reception centre opened on 31 May 2006, the protection unit has had  incidents of rape reported, either while undocumented migrants were crossing the border or in police custody, but Van Der Vyver suspects that rape has been under-reported. He gave an example of a woman who was gang-raped by six men, along with two other women, but she was the only victim who reported the assault.

In another incident, Van Der Vyver said a "Zimbabwean boy told us he was forced to rape women after the bandits he was travelling across the border with had first gang-raped them."

In the first seven months of 2007, the IOM processed 117,737 people repatriated from South Africa at its Beitbridge centre - about 40,000 more than in the last six months of 2006. Four out of five people passing through the IOM reception centre after repatriation by South Africa are young Zimbabwean men in their early twenties.

The centre was established to assist repatriated Zimbabweans who arrived destitute in their home country, often forcing women to turn to sex work, while men engaged in crime. Among other services, the reception centre provides free transport home and food packs.

Reiko Matsuyama, the IOM's HIV/AIDS project officer, based in Pretoria, South Africa, told IRIN/PlusNews that "anecdotal evidence suggests undocumented migrants are more vulnerable to HIV infections because of such practices as survival or transactional sexual relations", which meant that people would engage in sex for some sort of benefit, like accommodation or getting across a border.

Undocumented migrants were wary of engaging with officials in their adopted country for fear of deportation, and "they are less likely to seek medical services, not just for HIV/AIDS, but also for STDs [sexually transmitted diseases]," Matsuyama said, which also increased their risk of HIV infection.

The IOM said there were reasons why migrants, both undocumented and documented, displayed higher incidents of HIV/AIDS infections: migrants tended to engage in risky sex because of extended separation from their wives or partners; they experienced isolation, which made it difficult to reach or stay in conact with health services, or have access to condoms and health education.

These factors might be compounded by unfamiliarity with customs or languages. The IOM has also pointed out that the incidence of HIV/AIDS was often higher along major transport routes on which not only goods and people moved, but also disease.

Refugee's access to ARVs

Registered refugees have access to ARVs in many countries in the region, although Botswana, which pioneered the mass rollout of ARVs in 2002, does not dispense the life-prolonging medication to its refugee population.

The Botswanan refugee camp of Dukwi, about 150km north of Francistown, Botswana's second city, was established by the Lutheran World Federation in 1978 but since then has fallen under the aegis of the Office of the President.

Dukwi currently houses about 3,500 people: 1,200 Namibians from the Caprivi Strip and 1,200 refugees from Angola. The remainder include refugees from Burundi, the Democratic Republic of Congo, Rwanda, Somalia, Sudan and Uganda.

Since 2004 the Roman Catholic Church in Francistown has filled the gap left by the exclusion of refugees from Botswana's ARV programme by offering assistance to refugees and foreigners requiring treatment for HIV/AIDS.

Sister Bernadette Tembo, of the Catholic Church, told IRIN/PlusNews there were 79 people excluded from government ARV treatment on their books, among them refugees from Dukwi, although the programme was designed for only 50.

She said everyone, regardless of origin, could be tested for HIV free of charge in Botswana, but further tests, such as CD4 counts (which measure the strength of the immune system) were only available at no cost to Botswana nationals.

Dr Ndwapi Ndwapi, operational manager for the government's Masa (New Dawn) ARV programme, commented that the exclusion of non-nationals, including registered refugees, was based on the philosophy that citizens were part of "government health insurance" and "the qualifying criterion is to be a national".

However, the provision of ARVs to registered refugees would occur "probably before the end of this year," Ndwapi said, and dispensing would fall under the Office of the President of Botswana.

Five years after Botswana began its ARV rollout, 90 percent of citizens requiring the treatment have access to it or, to put it another way, Ndwapi said, of the 95,000 to 110,000 people needing treatment, 90,000 were receiving it.

Botswana's citizens are eligible for ARV treatment if they have a CD4 count below 200 or are living with an AIDS-related illness.

New strategies required

Laurie Bruns, regional HIV/AIDS coordinator for the UN Refugee Agency (UNHCR), told IRIN/PlusNews that although many countries in the region had policies allowing refugees access to free ARVs, there were still some instances where asylum seekers requiring ARVs were denied the medication.

Bruns conceded that the very nature of undocumented migrants, in that they were clandestine in their activities, crossed borders illegally or were repatriated to their home countries, made the provision of ARVs, or even HIV/AIDS education, very challenging.

"HIV/AIDS does not respect economic decline or conflict," she said. Strategies to provide universal access to ARV medication, regardless of a person's legal domicile or nationality, needed to be developed because "there are economically driven migrations, and the region needs to evolve [a common policy on HIV/AIDS], to address the changing nature of it."