The World Health Organization says up to 30 percent of the medicine sold in Africa is fake. It says such drugs are readily available on street corners and even some pharmacies. Health officials say counterfeit pharmaceuticals are killing thousands and making it harder to treat infections. Phuong Tran has more from VOA's West Africa bureau in Dakar.

At this market in the Senegalese capital, Dakar, tables are piled high with boxes of medication. The market is effectively an unofficial pharmacy. The vendor says he knows selling drugs in the market is illegal, but is not worried about getting caught.

He says he provides a valuable service because many cannot afford to go to the doctor to get prescriptions, or buy from pharmacies. He adds police do not bother him because religious leaders protect his medicine sales.

But Antonio Mazzitelli, the head of the U.N. Office on Drugs and Crime for West Africa, says these sales can be deadly.

Thousands have died throughout West Africa because of fake vaccines and other medications.

The U.N. crime officer says counterfeit smuggling networks take advantage of Africa's poor or non-existent drug regulatory systems to dump fraudulent drugs.

"There is a huge market and growing local production in certain countries that is taking more and more space and room in [the] West African economy," said Mazzitelli. "The counterfeit pharmaceutical products are structured like criminal organizations. So this is what really threatens the future of West Africa."

Papa Diop is Senegal's Ministry of Health director who oversees prescription drug imports, as well as drugs produced locally and sold in Senegal's 800 pharmacies. He says patients do not realize street drugs are not regulated and can contain deadly toxins. Diop compares Tetracycline, an antibiotic purchased at the street market with a drug by the same name sold at a pharmacy. The two cost about the same.

Diop says the different color and design on the street medication prove it is a copy. He says it could be filled with sand and completely ineffective or, at worst, filled with a deadly ingredient.

Health officials say counterfeit medicine can kill off some bacteria. But other ones can surface. The patient can eventually fall ill and infect others with newly discovered, drug-resistant bacteria. For example, Diop points out malaria has grown resistant to some treatments, partly because it has been treated with the wrong medication.

West African governments are fighting back. Earlier this week, Mauritanian officials seized and burned 36,000 bottles of counterfeit medicine that officials say mostly came from China, Syria, Nigeria and Hong Kong.

In Nigeria, which has an 80-percent rate of counterfeit drugs according to the France-based anti-crime organization Interpol, landlords can be arrested for storing counterfeit drugs.

Other West African countries have periodically launched advertisements about the danger of street medication. But sales of illegal prescription drugs still remain strong.

Major pharmaceutical companies have been accused of hiding knowledge of counterfeits of their medicines because they fear losing business from a damaged reputation.

Though some companies do share such information, no country legally requires notification. The U.S.-based Center for Medicines in the Public Interest estimates counterfeit drug sales will increase to $75 billion by 2010, a more than 90 per cent increase from 2005.