African countries including Kenya could record an increase in deadly infectious diseases due to the rapid decline of vulture populations in the continent.
A new report published in the Conservation Letters journal indicates that Africa's vultures are declining at rates of between 70 per cent and 97 per cent over three generations.
In Kenya, 5 out of the 8 vulture species in the country have a decline rate of about 84 per cent.
The vultures at risk include Ruppell's, White-backed, White-headed, Hooded and Lappet-faced vultures.
All the five birds are now considered as threatened species by the International Union for Conservation of Nature (IUCN) which creates awareness on the conservation status of various animals in the world.
Scientists therefore warn that the vultures could become extinct if threats to their existence are not addressed.
Dr Darcy Ogada, a lead author of the study from the National Museums of Kenya and the Peregrine Fund, said that vultures consume carcasses and keep our environment clean. Without them, mammalian scavengers such dogs and jackals would move in, posing a threat to human health.
Previous research has shown that upon feeding on infected carcases, vultures act as a death bed to harmful disease-causing organisms in the dead animals, hence killing and completely terminating them.
But other scavengers like wild dogs serve as reservoirs to the harmful pathogens – causing diseases such as rabies, anthrax or plague - and end up transmitting them to human beings directly or indirectly.
Kenya can take lessons from the ‘Asian Vulture Crisis’ – specifically in India- where massive declines of three vulture species (at a rate of over 95 per cent) was recorded in the 1990s resulting from the birds consuming carcasses of livestock infested with the veterinary diclofenac drug used to treat ailments in cows.
The huge decrease led to an influx in wild dogs in the country. Today, it is approximated that India has about 18 million such dogs which greatly contribute to the spread of rabies.
A World Health Organization (WHO) study estimated that 30,000 people in the Asian nation die from rabies each year with 70 per cent of the victims being children under the age of 15.
Leopards that normally prey on feral dogs also increased thereby spiking the number of attacks on people and their children.
However, the study’s authors note that African governments still have a window of opportunity to ward off such consequences arising from the decline in vulture populations.
Dr Ogada notes that the main threat to these birds in the country is poisoning from highly toxic agricultural pesticides. Sometimes pastoralist communities lace carcasses with these chemicals so as to kill wild animals like lions and hyenas that prey on their livestock.
When these game animals die, vultures ‘innocently’ descend to feed on them and end up dying from the contaminated meat.
The study also suggests that the recent rapid increase in elephant and rhino poaching throughout Africa has also contributed to the surge in vulture deaths.
Poachers intentionally poison carcasses to eliminate vultures since their presence – while hovering around the dead animals - may easily draw the attention of authorities thereby revealing their illicit activities.
Dr Ogada proposes effective regulation on the import and sale of agricultural pesticides and other chemicals commonly used as poisons.
“This will not only benefit vultures but all species wildly targeted by the pastoralists and poachers in Africa.”
To protect their critically endangered vultures, governments in Asia banned the use of the veterinary diclofenac drug which had wiped away huge populations of the birds.
Other threats to the birds in Africa include illegal trade in vulture body parts for traditional medicine, killing for bush meat, electrocution by power lines and mortality by wind turbines.
Dr Munir Virani, Africa Program Director for the Peregrine Fund said that outreach programmes geared towards pastoral communities in East Africa will be critical in ensuring that they perceive vultures as vital components of ecosystems and economies.
The international team of researchers that participated in the study included scientists from the National Museums of Kenya, Endangered Wildlife Trust, Makerere University and the Peregrine Fund.