Fifa has introduced emergency measures to stop players from taking undue advantage of its rules on switching nationality.
De Souza plays for Togo
Following a decision by its emergency committee, any player assuming a new nationality without a clear connection to that country will not be eligible to play for it.
The rule follows the decision of three Brazilians to play for the Qatar national team.
Fifa's decision will adversely African national teams who intend to naturalise foreign players in future.
Last year, Togo naturalised five Brazilians who played in the 2004 Nations Cup qualification games.
Had the Fifa ruling been in place by June 2003, the Togolese federation would have had a tough task in naturalising the players.
Kenya and Cape Verde, who played against Togo in the qualifiers, protested to Caf over Togo's action, but the west Africans claimed that some of their citizens can trace their roots back to Brazil.
Fifa's emergency committee ruled on Wednesday that players must have a "clear connection to that country" if they wished to wear the colours of a nation other than the one of their birth.
The rules now state a player must either have lived in a country for at least two years, or have a parent or grandparent who was born there.
Ailton hopes of switching to Qatar have been dealt a blow
Brazilian Francileudo dos Santos would have been unaffected by the new rule even if he hadn't naturalised for Tunisia ahead of the last Nations Cup.
Santos played two seasons in Tunisia and his Brazilian-born team mate Jose Clayton has played more than half of his club football in the country as well.
For Qatar, their FA had said the German-based trio of Ailton, Dede and Leandro would be given citizenship within a week.
"Naturalization that allows players with no obvious connection to the new country to play for that country's national team is not the aim and object of the (Fifa) statutes," said Fifa president Sepp Blatter.
Fifa's rules state a player who has never competed at international level can switch to another country if he is granted citizenship.
Qatar national manager Phillipe Troussier - the Frenchman who coached Japan at the last World Cup - has been trying to naturalize overseas players discarded by their national teams.
None of the Brazilian trio - Ailton, Dede and Leandro - have made full international appearances for Brazil and none have any previous connections with the Gulf state.
Ailton has reportedly been offered more than $1m to play for Qatar, but the Bundesliga's current top scorer denied he is a mercenary.
"Money is not the decisive factor here, as I earn good money at Werder Bremen," he said.
"If Brazil ignores me for 2006, then I have to find another way to get there."
Former Kenyan athlete Stephen Cherono switched allegiance to Qatar and won the World Championship gold medal for them in the 3000m steeplechase under the name of Saif Saeed Shaheen.
Blatter said he would raise the issue with the Fifa Congress, meeting in Paris in May, with a view to changing the statutes.