Tanzania has tightened its border control to prevent the spread of yellow fever after cases were reported in neighbouring countries.

Tanzanian Health minister Ummy Ally Mwalimu said that besides regular demands for valid vaccination certificates from travellers entering the country, the government was also ramping up local vaccination drives among vulnerable people.

“The ministry will ensure adequate availability of yellow fever vaccines in the country, oversee and stress cleanliness of the environments to check mosquitoes breeding, and continue to give civic yellow fever education to the citizens,” she said.

The measures came soon after neighbouring Kenya announced the outbreak of the acute and contagious viral disease in Isiolo, some 280km north of Nairobi. But Tanzania says Uganda, South Sudan and Chad also have detected suspected cases.

Tanzania has traditionally imposed a requirement for yellow fever certificates for travellers from ‘vulnerable’ countries, usually determined by past reported cases or outbreaks.

According to available data, Tanzania itself has not recorded any yellow fever since 1950. And authorities now say they use a rapid detection system for reporting infectious diseases such as yellow fever, launched in 2000.

Kenya, which has not experienced an outbreak of yellow fever since the 1990s, detected its first case in decades on January 12 and had until last week isolated 15 patients with fever, jaundice and muscle pain. 

Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes of the Aedes species.

Once contracted, it incubates in the body for three to six days, followed by an illness whose symptoms include fever, muscle pain with prominent backache, shivers, loss of appetite and nausea or vomiting. In severe cases, patients develop jaundice and bleeding.

Vaccination remains the single most important measure for preventing the disease.