Experts say zoonotic outbreaks becoming more frequent due to destruction of wildlife habitats
DAR ES SALAAM, Tanzania
As the world is still struggling to recover from the COVID-19 pandemic, the East African country of Tanzania is working to stem the spread of a mysterious disease which has so far claimed three lives and infected several others.
The disease identified as leptospirosis or hemorrhagic infection leading to nose bleeding is believed to have been transmitted from wild animals – thus another zoonotic disease affecting humans after the COVID-19 in recent times.
Speaking to Anadolu Agency, Health Minister Ummy Mwalimu said the nosebleed disease, caused by a bacteria known as Leptospira interrogans has been transmitted to humans from rodents, dogs, antelope, and wild birds.
“Environmental destruction has brought wild animals into close interaction with people,” she said.
Aifello Sichalwe, Tanzania’s chief medical officer, said a team of medical experts has been working in the southeastern Lindi region to identify the disease that has claimed three lives and has infected 20 people, one of them is still hospitalized.
Cecilia Mville, a virologist at Kibong’oto Infectious Diseases hospital in Kilimanjaro, said zoonotic pathogens are increasingly making a leap from animals to humans due to the changing environment.
“It is important to understand the interaction of different species and how they are driving the transmission of zoonotic diseases. Many animal species including rodents can harbor pathogens without being affected themselves,” she said.
Mville said wild animals that migrate or have large territories, including antelope also make effective vectors.
“I have never seen such a strange illness, I felt dizzy and was perpetually bleeding in the nose when I lost consciousness,” said Rashid Kassim, a resident of Lindi who was infected with a strange disease.
Growing risk of outbreaks
The African continent is facing a growing risk of outbreaks caused by zoonotic pathogens, including the monkeypox virus which originated in animals and then switched species and infected humans, the World Health Organization (WHO) warned last week.
According to WHO analysis, there has been a 63% increase in the number of zoonotic outbreaks in the region in the past decade.
The UN’s health body recorded 1,843 public health risks between 2001-2022 out of which 30% were zoonotic outbreaks.
Matshidiso Moeti, WHO regional director for Africa, said Infections originating in animals and then jumping to humans have been happening for centuries, but the risk of mass infections and deaths had been relatively limited in Africa.
She said the growing demand for food, rapid urbanism, and encroachment on the wildlife sanctuaries has been some of the reasons for such outbreaks.
Tanzania’s President Samia Suluhu Hassan warned that hemorrhagic infection whose symptoms include fever, headaches, fatigue, and perpetual nosebleed has been caused by human interaction with wildlife since people build settlements in the vicinity of forests.
She said the wild animals have been disrupted from their natural habitats and have been forced to go closer to human settlement.
Mary Nyalu, a senior veterinary epidemiologist in the Kilimanjaro region, said there is a strong link between the destruction of natural habitats of animals and the rise of man-vector contact that lead to the surge of zoonotic diseases.
“The changes in ecological conditions have led to animals such as antelopes fleeing their natural habitats and feeding on farm produce,” she said.
Human and wildlife proximity dangerous
Nyalu said the growing proximity between humans and wildlife has triggered the rate of disease transmission including nosebleeds.
According to him, the spillover from wildlife is caused by land-use change including forest destruction for energy and building activities.
“When humans encroach wildlife habitats there are increasing chances of direct contact with infected species that can pass on deadly pathogens,” Nyalu said.
Zoonosis is a widespread, complex, and multifaceted phenomenon which does not discriminate between borders, and by nature does not always discriminate between hosts, scientists said.
Humans have created conditions for those pathogens to thrive, and rapid human expansion would lead to the emergence of new diseases.