The offspring of African killer bees, which have killed up to 1,000 South Americans since 1957, may be headed north, and doctors are only beginning to understand what their stings do to the human body.

One little-known effect of multiple bee stings is sudden kidney failure, Colombian doctors report in the Annals of Internal Medicine. The doctors report five such cases, one resulting in death, in people who received more than 1,000 stings.

Twenty-six swarms of the aggressive African bee escaped from captivity in Brazil in 1957. They mated with the more docile European bee. The result, an "africanized" bee, "will be reaching other countries of Central and North America on its northward spread," write Dr. Gonzalo Mejia and several colleagues.

Most people killed thus far in South America have been elderly, children and others unable to flee, predominantly in rural areas, where little medical care is available. As a result, wrote Dr. Orley R. Taylor Jr. of the University of Kansas in an accompanying editorial, the exact effect on humans is unknown. Even the content of the venom is in dispute.

The bees are expected to reach the southern United States by late 1988 or early 1989, and eventually may travel as far north as parts of South Carolina. Most encounters with humans are expected in New Orleans, Florida, Los Angeles and a few other heavily populated areas.

With more medical care available there than in South America, doctors hope to learn more about the effects on humans, Taylor writes.

But for impatient investigators, a trip to Mexico may be in order. "African bees will reach that country in the coming months," Taylor writes, "and stinging incidents should begin to increase n Chiapas, Campeche and Yucatan in 1987."