A drive by West African nations to tackle zoonotic diseases, those that jump from animals to humans, could help to protect the region from future health crises such as the world's worst Ebola outbreak, a United Nations official said on Thursday.

Ministers from the region met in Senegal last week to adopt an approach to infectious diseases that will address human and animal health together, and see countries work collaboratively to contain outbreaks of diseases ranging from bird flu to Zika.

Three-quarters of emerging infectious diseases in recent years have spread to humans from animals or animal products, according to the World Health Organization (WHO).

The Ebola outbreak in West Africa, which infected more than 28,600 people and killed some 11,300 across Guinea, Liberia and Sierra Leone, began in December 2013 when a young boy in rural Guinea came into contact with an infected animal, the WHO said.

"There are no boundaries between humans and animals ... we cannot have separate health mechanisms and responses any longer," said WHO representative Ibrahima Soce Fall.

"Ebola was a turning point in terms of taking a new approach to zoonotic diseases," he told the Thomson Reuters Foundation.

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West Africa is dealing with outbreaks of several zoonotic diseases, such as bird flu in Cameroon and Nigeria, Rift Valley fever in Niger, and the recent emergence of the Zika virus strain from Brazil in Cape Verde and Guinea-Bissau.

In addition to their health impact, such outbreaks also inflict a heavy toll on the economy. Guinea, Liberia and Sierra Leone are estimated to have lost a collective $2.2 billion in gross domestic product (GDP) in 2015, said the World Bank.

Countries in the region agreed at the One Health conference in Dakar to carry out national risk assessments, set up alert mechanisms for disease outbreaks, and ensure their laboratories can handle both human and animal samples, according to the WHO.

Improved surveillance at community level is crucial to identifying outbreaks in animals before they spread to humans and develop into national or international crises, Fall said.

Yet some countries in West Africa may struggle to implement the new approach in the near future amid a shortage of veterinarians and domestic financing, the WHO official added.

"Certain countries are going to move slower than others, so implementing the approach region-wide will take time," he said.