LUANDA, Angola . There are parasites of all kinds in poor countries.

One variety is intestinal, the worms that afflict countless children. In a hospital here in Angola, nurses pointed to a little girl named Marcelina, who they said was at risk of dying from anemia caused by worms and malnutrition. She had so many worms she was spitting them up.

The other kind of parasite afflicting Angolan children is the crooked official, often working with Western executives. It’s not a coincidence that Angola is a center for both kinds of parasites.

“Much of the health care budget gets stolen,” Rafael Marques de Morais, an investigative journalist in Angola, told me. “The biggest problem in this country is corruption.”

When officials pocket health care funds, Marques de Morais noted, children suffer. Likewise, doctors and nurses sometimes take medicines from their clinics and sell them in the markets. At the first street stall I went to, I found donated Novartis anti-malaria medicine for sale . even though it was marked “not for retail sale.”

What unsettles me is the Western role in this corruption. Western oil companies and banks work closely with Angolan officials, enabling the kleptocracy, and the United States and other governments mostly avert their eyes from the corruption, repression and humanitarian catastrophe.

A generation ago, the United States supported a brutal warlord, Jonas Savimbi, in Angola’s civil war. He lost. Now, because of oil interests, we have allied ourselves with the corrupt and autocratic winner, President Jose Eduardo dos Santos, in a way that also will also be remembered with embarrassment.

Secretary of State John Kerry visited for two days last year, and, in December, he hailed “the great dividends of our partnership with Angola.” He and other officials have enveloped Angola in a big hug.

“Publicly, the U.S. is mute, or at most tepid, when it comes to the crushing state repression,” noted Leslie Lefkow of Human Rights Watch.

Tom Burgis of The Financial Times has a powerful new book, “The Looting Machine,” asserting that firms, including Goldman Sachs and Carlyle Group, backed an oil company called Cobalt in investing in oil operations in which Angolan officials secretly held stakes worth staggering sums.

Likewise, American oil companies like ExxonMobil, Chevron and ConocoPhillips are active in Angola. Groups like the One Campaign have pushed to require international oil companies to disclose sums paid to governments so that the money can be tracked . increasing the chance that it makes it into state coffers and not private pockets. Europe and Canada are requiring their companies to make these disclosures.

But the American Petroleum Institute is lobbying hard to water down disclosure requirements. The oil industry apparently seeks to sustain an opaque system that has allowed the Angolan president’s family to earn billions even as the country ranks No. 1 worldwide in child mortality rates.

American executives argue that it’s naive to hold them to international standards when they’re competing with, say, Chinese companies, which excel at paying bribes. Chinese companies are everywhere in Angola; one Chinese executive estimated that 100,000 Chinese now work in the country. But, in this case, Europe and Canada are trying to raise standards. So let’s not be China!

The way to help children like Marcelina, or the 150,000 who die each year in Angola, is not just to hand out medicines. It’s to hold Angola’s leaders accountable so that they use oil money to buy deworming medicine and not $2,000-a-bottle Dom Perignon. It’s to support those brave Angolans like Marques de Morais who are trying to improve governance.

Marques de Morais has tracked $3 billion accumulated by President dos Santos’s daughter, the $13 million refurbishment of the presidential palace, the Lexus LX 570 luxury S.U.V.’s given to each member of Parliament . all at a time when children aren’t consistently getting five-cent deworming pills.

I’m honored to be in the same profession as Marques de Morais. He went on trial Tuesday for criminal defamation and could face years in prison; if the United States wants to signal that it cares about corruption, Secretary Kerry could tweet his support and the American ambassador could invite Marques de Morais to a very public lunch.

The last time Marques de Morais was imprisoned, in the 1990s, he said he was released only when the United States ambassador to the United Nations at the time, Richard Holbrooke, visited Angola and insisted on seeing Marques de Morais . in prison if necessary. Angola hurriedly freed him.

In other words, we have influence, if we’re willing to use it. And when children are spitting up worms and a country ranks No. 1 in child mortality worldwide, let’s exercise that influence rather than remaining complicit.