Here is a quote I just saw in the news. It describes how lions give it to each other, which was kind of a no brainer, but it does not address how it spead into feline populations in the first place. Even though it says that leopards and cheetahs are less susceptible to it, I do not think that this is looking too good for them, either.

"Virus Infects Lions

The Herald (Harare)

July 14, 2004
Posted to the web July 14, 2004

Isdore Guvamombe
Harare

FELINE Immunedeficiency Virus, the equivalent of the HIV in human beings, has infected lions in Kruger National Park in South Africa, threatening the viability of the Great Limpopo Transfrontier Park.

The megapark, joining Gonarezhou in Zimbabwe, Kruger in South Africa and Gaza in Mozambique, is the world's biggest wildlife sanctuary, but veterinary workers in Kruger say between 60 and 80 percent of the lions in South Africa are now under threat.

The Zimbabwe Parks and Wildlife Management Authority was aware of the disease on the other side of the Limpopo but said it was closely monitoring its development.

The authority's chief warden, Mr Lovemore Mungwashu, said the disease was still in the southernmost part of Kruger National Park and that Zimbabwe was still safe.

"Yes, the Aids-like disease has been discovered in South Africa and we are carefully watching it.

"Although Kruger is part of the transfrontier park, the disease is still confined to the southern- most part of the park and Zimbabwe is still safe," said Mr Mungwashu.

The primary mode of FIV transmission is sexual contact and bite wounds.

On rare occasions infection is transmitted from mother to cub, usually on passage through the birth canal or when newly-born cubs ingest contaminated milk.

Infected animals usually appear normal for a few years until infection eventually leads to the gradual collapse of the immune system, resulting in the animal failing to protect itself from infections.

Common among the symptoms are persistent fever and diarrhoea with a loss of appetite, poor coat condition, chronic or recurrent infection of the skin and urinary bladder, abortions and behaviour change, including seizures.

All this is followed by slow but progressive weight loss and neurological disorders.

Zimbabwe shares a long stretch of the border with South Africa's Kruger National Park in Gonarezhou National Park, the verdant wildlife sanctuary, where lions roam wild and free.

Given the long-range migratory habits of lions and the territorial dominance of huge males, there are fears that the disease will spread to Zimbabwe and Mozambique.

Other felines, the leopard and cheetah, also have FIV but are said to be less susceptible because they are more solitary.

Lion prides are more affected by the disease because they are highly sociable and are in constant physical contact with each other.