Because of a typographical error, a story yesterday on Argentina's decision to ratify a Latin denuclearization treaty misrepresented U.S. views of an aspect of that issue. The affected paragraph should read. The Brazilians have consistently refused to respond to U.S. appeals for deferral of their plans to purchases an entire nuclear reprocessing cycle from West Germany. But U.S. officials privately maintain that they still have hope. That West German technology, scheduled to reach Brazil in 1982, would put the Brazilians ahead in a Latin nuclear race that Argentina dominated for more than 20 years. The vote totals in thegovernor's race in Loudoun County were reversed in a chart that appeared in the Nov. 19 editions of The Washington Post. Actually, Henry E. Howell received 4,689 votes in Loudoun; John N. Dalton, 6,668; and Alan Ogden, 91.

In a joint communique today with the United States, Argentina - South America's preeminent nuclear power - agreed to ratify a treaty that prohibits the development of nuclear weapons in Latin America.

The agreement clears a major obstacle from the path of nuclear technology transfer to Argentina from the United States and Canada. Such transfers were prohibited earlier this year by President Carter for all countries that were not parties to a comprehensive nonproliferation accord. Canada concurred in this step.

While the agreement marks the accomplishment of one goal of Secretary of State Cyrus Vance's visit here, U.S. officials said progress on a second objective - human rights - was slight.

In a clear statement of concern to the Argentine military government, U.S. Assistant Secretary of State for Human Rights Patricia Derian turned ove a list of some 7,500 persons that human rights groups say have been illegally imprisoned or murdered, or have disappeared here.

Derian, Assistant Secretary of State for Latin America Terence Todman and State Department nuclear negotiator Gerard Smith are accompanying Vance on a four-day tour of Argentina, Brazil and Venezuela.

Although the Argentina stop is for only one day, both Vance and Derian spent several hours today meeting with individual families of persons who have disappeared or are imprisoned, including the family of prominent newspaper publisher Jacobo Timerman, who has been imprisoned without charge here since last April. Vance also met with local human rights organizations and leaders of the Argentine Jewish community concerned about charges of official anti-Semitism here.

Last February, the Carter administration cut off sales of all military weapons to the Argentine junta, which according to documents of rights groups has imprisoned between 10,000 and 15,000 persons. Only half of those, the documents say, have been officially recognized as under detention by the junta, and the rest are listed as having disappeared.

The list of 7,500 names was compiled by a coalition of human rights organizations. Names were submitted by Amnesty International and the World Council of Churches, among others.

State Department spokesman John Trattner said the human rights issue was discussed "at length" during Vance's meetings today with Argentine President Gen. Jorge Videla and Foreign Minister Oscar Montes.

The nuclear part of the communique through in Carter's strict nonproliferation policy, and gives Vance extra ammunition to take to Brazil Tuesday.

The Brazilians have consistently refused to respond to U.S. appeals for deferral of their plans to purchase an entire nuclear reprocessing cycle from West Germany. But U.S. officials maintain that they still have hope that West Germany technology, scheduled to reach Brazil in 1982, would put the Brazilians ahead in a Latin nuclear race that Argentina dominated for more than 20 years.

Argentina has one reactor now in operation. Another plant now under construction is expected to be on line in 1980, and a third reactor is scheduled for completion in 1984.

All of the plants are designed to use low-enriched uranium and heavy water - meaning their radioactive by-products cannot easily be used for bomb-building.

Although Argentina has an agreement to purchase both heavy water and heavy-water production technology from Canada. The Canadians have joined with the US in refusing to export any nuclear technology or products to countries who refuse to sign international nonproliferation and safeguards accords.

The administration has been willing to accept either the nonproliferation treaty or the Latin nuclear agreement drafted in Tlateloco, Mexico in 1967 as meeting this requirement for Latin American Nations.

Progress of implementing the Latin treaty, has been stymied by an Argentina-Brazil nuclear rivalry, although both countries have vowed they seek only peaceful nuclear uses.

While Argentina signed the Tlatelolco agreement. It has refused full ratification until the United States can assure the Argentines that Brazil will not receive reprocessing technology that would greatly enhance its bomb-building capabilities.