Western tourists who visit Africa are finding their itineraries curtailed due to tnesions on the eastern part of the continent.

Since the early years of this century, many travelers began their African safaries from Nairobi's venerable New Stanley Hotel. But conversations at the Stanley's Thorn Tree Cafe now center more on where you can't go than on anything else.

"Kenya's lovely," said 19-year-old Dori Maynard of Washington, D.C., "but I want to see other African countries as well."

Eastern Africa is being torn apart by polical violence, supicion and jealousy. Kenya remains about the only accessible country for the thousands of tourist who land in Nairobi each day.

Brian Schwartz, 24, of New York City went to Uganda last week to climb the spectacular Mountains of the Moon, where ferns grow to heights of 20 feet. But before he could even leave the capital, Kampala, he was piced up by policemen for no apparent reason and wound up spending three terrifying nights in jail without ever being charged.

"The Ugandans just couldn't understand that I wanted to see their country to become a more worldly, better person. They kept asking. 'How will this make you a better lawyer?" said Schwartz, a Yale Law School graduate, after returning to Nairoki. Twice during his Ugandan ordeal he thought Ugandan authorities were going to kill him.

According to Schwartz, there are only 10 to 20 tourists in all of Uganda and most are in jail or have been picked up for questioning by machine gun-toting authorities whom Shcwartz labels "the most evil people I've ever seen."

Nevertheless, a young Canadian who has spent a month in Kenya said he was prepared to enter Uganda. "I want to travel to South Africa to work," he said, revealing that his funds are running low and the possibility of earning his fare home doesn't exist elsewhere in Africa.

"My plan was to travel south through Tanzania, but now that's not possible," he said. Tanzania closed its border with Kenya about a month ago amid growing hostility between the two countries following the collapse of the airlines they ran jointly with Uganda.

More than 150 Americans who were stuck in Tanzania had to be airlifted to Kenya by the U.S. government, and now foreigners who wish to see Tanzania's famed Seregeti National Park, Ngorongoro Crarter and Mount Kilimanjaro must fly directly to Dar Es Salaam and not enter from Kenya.

"Kenya has a lot to offer," said Bob Augustino of Brooklyn, "but I'd like to see at least one more African country before heading home. I heard that lots of people speak Italian in Somalia so I went to their embassy in Nairobi to get a visa.

"The official there was very polite, but he told me he'd have to send my application to Mogadishu and that I should come back in six weeks for the answer." Later, Augustino learned that virtually no American tourists receive visas for Somalia a revolutionary socialist military dictatorship with close ties to the Soviet Union.

Kenya's northern neighbor, Ethiopia, used to be one of Africa's most popular tourist destinations, but because of political violence during the past few years the trade has dropped to almost nothing.

Even from the Hilton Hotel in Addis Ababa it is not to hear gunfire as member of the Ethiopian Peoples Revolutionary Party and the All Ethiopian Socialist Union shoot it out. Because business is slack, the Hilton offers half-price rooms to revelers stranded there after midnight, when a "shoot-on-sight" curfew goes into effect.

Some adventurers, dissatisfied with an African odyssey that takes in only one country, tried to visit the Sundan, which also borders Kenya.

After learning that the only road there passes through northern Uganda's Langi-speaking area, they decided to fly to Juba. The Langi are the target of a reported extermination campaign by President Idi Amin's so-called "death squads." However, when the would-be travelers learned that more than 100 persons died of the mysterious green monkey fever in the southern Sudan last year, and that only a few weeks ago a missionary was accidentally shot and killed and two others wounded at Juba Airport during an army revolt, they concluded that Kenya offered enough Afircan adventure.

Most Kenyans in the tourist industry are not complaining. Though Nairobi safari companies relied heavily on Tanzanian wildlife attractions, Kenyan game lodges are at this moment so fully booked that the old-fashioned, luxury-tented safari a la Hemingway and Teddy Roosevelt is by necessity having a revival.