Kammala jumla mai zuwa: Zeferino, dan wasan Olympics sau uku, ya fara fafatawa a Cape Verde a wani taro a Maia, Portugal wanda ya kafa tarihin kasa a tseren tseren mita 3000 wanda har yanzu yana nan. A shekara mai zuwa a Wasannin Olympics na bazara na 1996 a Atlanta, Zeferino ya shiga tarihi tare da Henry Andrade da Isménia do Frederico ta hanyar zama 'yan wasa na farko da za su wakilci ƙaramar ƙasar Afirka a Wasannin Olympic. A tseren marathon na maza ya gama na 94 a cikin lokaci na 2: 34:13. A shekara mai zuwa ya yi gasa a Gasar Cin Kofin Duniya ta 1997, inda ya gama na 37 a tseren marathon tare da lokacin 2: 25:56. Shekaru biyu bayan haka a watan Fabrairun 1999, Zeferino ya yi rikodin mafi kyawun lokacinsa a cikin marathon a Marathon na Sevilla wanda ya gama a cikin 2: 23:16. Watanni shida bayan haka a gasar zakarun Turai ta 1999, ya gama tseren marathon a hankali a cikin 2: 26: 03 wanda ya sanya shi a matsayi na 39. A Wasannin Olympics na bazara na 2000 a Sydney, Zeferino ya inganta a lokaci da matsayi daga shekaru hudu da suka gabata yana tsallaka layin a matsayi na 67 a cikin lokaci na 2: 29:46. A shekara mai zuwa, ya kammala a gasar zakarun duniya ta 2001, inda ya gama tseren marathon a matsayi na 51 a cikin 2: 32:46. Gasar karshe ta Zeferino ita ce
marathon a Wasannin Athens na 2004 inda yana da shekaru 38, ya gama a 78th tare da lokacin 2: 36:22.