A rapid spread of the mpox virus in sub-Saharan Africa could add to the fiscal pressures many countries in the region are already experiencing, ratings agency Fitch said on Wednesday.

Potentially deadly mpox was declared global health emergency by the World Health Organisation earlier this month after a new strain, known as clade Ib, spread from the Democratic Republic of Congo to neighbouring states.

"Virus outbreaks can have significant economic and fiscal effects," Fitch said in a statement, adding that some of the negative impact could be offset, however, by increased funding from rich donor nations.

Ivory Coast, Kenya, Rwanda, South Africa and Uganda are some of the Fitch-rated issuers that have reported mpox cases, the ratings agency said.

"In most of these, the number of confirmed mpox cases is very low, often in the single digits. However, there could be underreporting in some countries," it said.

Some 13 African countries have reported more than 22 800 mpox cases and 622 deaths this year, the Africa Centres for Disease Control and Prevention said on Tuesday, up from 12 countries reporting over 18 900 cases and 541 deaths a week earlier.

Several strains of mpox are spreading in Africa at the same time, but Congo still accounts for the vast majority of the cases.

In the event of a substantial increase in mpox case counts, Fitch said the main impact on economies would likely be on consumption and production.

Tourism could also be hit – a potentially significant factor in Kenya, Rwanda and Uganda - where United Nations' data estimates it accounted for 11%, 20% and 19%, respectively, of total goods and services export earnings in 2022.

"There could also be challenges managing inflationary effects, especially if food production and/or logistics are significantly disrupted," Fitch added, as well as crimping tax revenues and requiring more healthcare spending.