Africa is faced with a new scourge it is ill prepared to fight: heroin.

Virtually unknown a few years ago on a continent already wracked by ruinous droughts, killer diseases and civil strife, heroin is slowly making its appearance in African capitals.

As a direct result of the increasing use of the "African connection" - a transit route between India and Pakistan and established markets in the United States and Europe - experts fear African heroin addiction will grow rapidly.

"We never knew in the past it could get this serious," said the head of Kenya's anti-narcotics unit who asked not to be named for security reasons. "It's a fairly new phenomenon."

Until 1984, there was virtually no heroin in Africa. In 1986, says the international police organization Interpol, 130 pounds were seized. For the first six months of 1988, Paris-based Interpol reported seizures totalling 145 pounds.

"In the West we estimate seizures represent about 10 percent of the total," said a Western narcotics expert. "Here we don't even know whether that would be an accurate estimate. It may well be on the low side."

"People may have brought in bags and bags of the stuff without being caught," the Kenyan narcotics official said. "For a long time heroin was not a priority. Now we have to move fast."

Corrupt customs officials, lack of resources and specialized knowledge - not to mention largely unpatrolled borders - contribute to dragging Africa into the highly organized international racket.

Kenya and Nigeria are the main African transit points. But Kenya's narcotics chief has only 20 men under his command, the only policemen who "can recognize heroin when they see it," he said.

Next year 50 more will be trained by donor countries, and organizations who have also pledged material assistance. But much more will be needed simply to keep the traffic at "manageable" levels.

The senior officer, who conducts almost every drug bust himself, has no boats to patrol Kenya's 960-mile coastline and the Kenyan portion of Lake Victoria, the world's second largest freshwater lake. His squad has few vehicles and little equipment.

What's more, many local judges are hardly aware of the nature of heroin, and arrested traffickers often get off lightly.

Last year a man caught with 6.4 pounds of heroin was fined $277 - the retail price of just over two grams of heroin on international markets. More recently a woman arrested at Nairobi airport with 1.3 pounds of heroin was released on a $554 bond.

Yet Kenya, which plans a major extension of its anti-narcotics squad and the new drug laws, is still more efficient than most African countries in combating the illegal trade.

"Kenya, Tanzania, Zambia and Ethiopia are among the few countries that are doing something to stop the traffic," said one expert. "Most African policy-makers are not aware of the dangers. They don't believe this can be happening in Africa."

Lack of awareness of the drug traffic and its dangers has discouraged pan-African cooperation in fighting it, while encouraging "couriers" to use African routes.

Many governments seem to think that since their countries do not produce opium and its heroin derivative they do not have a consumption problem. Experts like the U.N. International Narcotics Board say "drug abuse nearly always ensues wherever illicit trafficking takes place."

The worst-hit country is the Indian Ocean island of Mauritius, a transit route long before other African countries.

"It has a tremendous consumer problem," said a Western expert. "Per capita it's as big as in the United States. We're talking of between 20,000 and 40,000 consumers out of a 1 million population."

In Kenya the number of addicts is still fairly low - police know of about 100 in Nairobi - but is likely to grow. Many Kenyans traditionally smoke marijuana - known as "bhang" - which grows prolifically in this East African country.

"Heroin is new to our people," the Kenyan narcotics officer said. "They could get hooked without knowing what they're getting into. They'll get a rude awakening."

The same might be true in any of Africa's 52 countries, all of which have been touched in some way by the international drugs trade.

"The problems facing the individual governments of Africa are huge: famine, disease, economic and political turmoil and an ever-growing population eager to sample the same standard of living of the more developed nations," Interpol said.

"One thing that no country in Africa needs is a drug problem."