A DOG carrying the KwaZulu-Natal strain of rabies has been confirmed as the source of the viral infection that is suspected of killing a Soweto toddler at the weekend.

Veterinary experts have confirmed that the animal was carrying the strain - canid biotype - originating from KwaZulu-Natal.

The dog might have bitten or scratched the toddler or bitten other dogs that might have come into contact with the child a month ago.

Humans can contract rabies when saliva from an infected dog comes into contact with their blood. Lucille Bloomberg of the National Institute of Communicable Diseases (NCID) said earlier tests revealed the rabies strain matched the one found in the province.

"The strain definitely matches the one found in KwaZulu-Natal. The various strains can be differentiated using laboratory equipment and what we found gives us a focus point," Bloomberg said.

She said the girl's symptoms suggested that she might have died of rabies but that was still to be confirmed.

"She showed signs of increased salivation, convulsions and throat spasms," she said.

But Bloomberg said they had not found the actual dog. MEC Nandi Mayathula-Khoza announced the girl's death on Monday at the start of a vaccination drive at the Kopanong Centre in Dobsonville, Soweto.

Gauteng Veterinary Services chief director Malcolm de Budé said the decision to refer the case to the NICD for investigation was a sign that the situation was serious.

"The areas with the highest prevalence of rabies are KwaZulu- Natal, Eastern Cape, Mpumalanga and Limpopo. This is due to the high population numbers, coupled with the low quality of veterinary services in those areas."

Affected Gauteng areas include Sophiatown, Bushkoppies in Eldorado Estates, Meredale, Kibler Park and Dobsonville in Soweto.