The confiscation of more than 400 pounds of zebra meat destined for Nairobi markets is drawing new attention to the trade in illegal game meat in Kenya. As Nick Wadhams reports from our East Africa bureau in Nairobi, wildlife officials have found it nearly impossible to control the bushmeat trade, which can pose serious health risks.

Three people were arrested after Kenyan police inspected a car bound for Nairobi early Saturday morning and found plastic bags full of the zebra and wildebeest meat. The meat was unrefrigerated and had not been inspected, but would almost certainly have gone on sale in Nairobi.

Officials with the Kenya Wildlife Service (KWS) say the seizure is part of a wider effort to crack down on the hunt and sale of game such as zebra, giraffe and buffalo in Kenya. Later Saturday, thirteen people were arrested in the Tsavo West National Park on poaching allegations.

KWS spokesman Gichuki Kabukuru says the meat is illegal and can pose serious health risks because it has not been properly prepared or handled. People may also not know what they are buying because the meat is sometimes passed off as beef from cattle or goats.

"That is one thing we've been trying to send the public, because the consumption of that meat, which has not been tested essentially, exposes the public to such diseases as anthrax and a number of these beef-oriented diseases. It is a constant threat," he said.

The bushmeat trade has been a major concern in Kenya for years. Officials say one problem is that the criminal code's punishment for poachers are not severe. That means that poachers are coming across the border from Tanzania, where anti-poaching laws are more strict. Seven of those arrested in the Tsavo West incident were Tanzanian.

And Kenya's population is growing so quickly that people come into contact with animals more often or are desperate for something to eat.

Kenya hopes to address all of those issues with an overhauled wildlife policy, which is set to come before parliament later this year. But KWS spokesman Kabukuru says it's hard to tell people not to stop hunting game illegally.

"The bushmeat fight has been an ongoing process. Our greatest challenge is one the issue of population growth, of rapid population growth," he added.  "So definitely they hunt for subsistence. Even when we are putting everything in place it is very difficult to convince a hungry man that he will not eat."

One of the starkest signs of the extent of the bushmeat trade came in a 2004 investigation. The London-based conservation group Born Free conducted a random sample of some 200 butchers in Nairobi and found that a quarter of the meat was bushmeat, while 20 percent was game meat mixed with meat from goats and other domestic animals.