Zimbabwean orphans Evans, 13, and Edmond Mahlangu, 8, crossed a mountain range on foot to get to Mozambique where they are slowly recovering on life-saving AIDS drugs in short supply back home.
"We walked for a day in the mountains. We had to keep quiet because of the guards," recounted the boys' 17-year-old sister, Emmaculate, who made the 10 kilometre (six miles) journey with her HIV-positive siblings at the beginning of February.
"It was tough above all for my brothers. They had to walk alone because I was carrying bags."
The children have taken refuge with an aunt not far from the Machipanda border post in the central Mozambican province of Manica.
Orphaned in 2006, the children lived with their grandmother in Mutare on the Zimbabwean side of the border until she banished them in January.
"My grandmother chased us away. She was afraid of the boys because they are sick. She was scared to touch them, even to cook for them," Emmaculate told AFP.
Without any identity documents, the children fled to Mozambique as little hope remained in their home country with a critical lack of food and drugs and official inflation exceeding 100,000 percent -- a state of affairs widely blamed on longtime President Robert Mugabe whose controversial land reform policies, seizing white-owned farms for redistribution to landless blacks, all but killed commercial agriculture and scared off foreign investors.
Evans and Edmond were put on anti-retroviral (ARV) treatment as soon as they arrived in Mozambique.
"I feel better now. It's not so bad as before," the elder boy said timidly, his body covered in a severe rash.
The boys had been given ARVs once before, back home in Zimbabwe, but government-sponsored drugs are hard to come by and private sector prices are prohibitive.
'We accommodate all patients without discriminiating'
Mozambican officials say Zimbabweans flock across the border to access ARVs.
"Hundreds of Zimbabweans come here to get AIDS treatment that Mozambique provides for free," said Aarao Uaquiço, local coordinator of the national council against AIDS, a government body.
The Zimbabwean beneficiaries' numbers are not well documented.
"We accommodate all patients without discriminating," said provincial head doctor Marilia Pugas.
More than 100,000 HIV-positive people now receive free ARV treatment in Mozambique, up from 7,000 in 2005.
"It is extraordinary. But the costs are enormous," said Maurico Cysne, Mozambican representative of the United Nations Programme on AIDS (UNAIDS).
"Treatment costs 50 dollars (per person) a year."
One of the poorest countries in the world, Mozambique like most of southern Africa is buckling under the impact of AIDS.
It has an average HIV prevalence rate of 16 percent of the population, rising to 23 percent in some areas of Manica, a transit point for heavy trucks making their way from Zimbabwe, Zambia and Malawi to the Mozambican port of Beira.
"There are prostitutes all along the route," said Uaquiço. "Many are Zimbabweans more concerned about survival than protecting themselves against AIDS."
According to UNAIDS latest statistics, Zimbabwe's HIV prevalence is on the decrease with 15.6 percent of adults between 15 and 49 affected.
With the scrapping of visa requirements between the two countries last November, the number of Zimbabweans crossing into Mozambique has risen sharply.
Paradoxically, clandestine migration also shot up as Zimbabwean authorities are unable to reverse a a massive backlog in issuing passports required to enter Mozambique.
"In January, 22,636 Zimbabweans, mostly women, crossed the border legally at three posts in Manica, most through Machipanda -- up from 8,971 in January 2007," said provincial migration service director Felipe Cumbe.
"They are allowed to stay for 30 days but 85 percent make their purchases and return. We don't know what happens to the other 15 percent.
"Many others, including children and very young girls, cross illegally, added Alberto Limeme, customs chief of Machipanda.
The border is not easy to police, with only 50 officers patrolling the 500-kilometre stretch on foot.
And distinguishing Zimbabweans from the local population was near impossible with residents on both sides of the border speak Shona, a local dialect.
Groups from both countries settled along the border during Zimbabwe's war of independence from Britain and Mozambique's from Portugal in the 1970s -- and inhabitants of the border zone were ethnically very similar.
"There are always people coming and going," said Cysne.