This is five months after closing transport links to prevent the spread of the worst outbreak on record of the deadly Ebola virus.
Senegal had already lifted in November a ban on air and maritime traffic with Guinea, Liberia and Sierra Leone - the three countries worst-affected by the epidemic of the deadly hemorrhagic fever.
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In recent weeks, the World Health Organization (WHO) has said the outbreak in West Africa appears to be ebbing as the rate of new infections has declined. In the week to 18 January there were 20 new cases in Guinea, versus 45 the week before, WHO data showed.
“The decision to open the border follows meetings between Senegalese and Guinean authorities, in the course of which the important efforts made by the sister republic of Guinea to fight the Ebola virus were noted,” said a ministry statement.
Senegal itself recorded a single case of Ebola, a student who crossed the border from Guinea, but a wider outbreak was prevented. Senegal was declared Ebola-free on 17 October but said it would enforce measures to avoid any propagation of the disease.
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Experts have warned against border closures and travel restrictions as a means of containing the virus.
In the past year, 21,724 Ebola cases have been reported in nine countries and 8,641 people have died, most of them in Liberia, Guinea and Sierra Leone, according to the WHO.