Loss of biodiversity ‘threatens human health’

LONDON - A new research has warned that the loss of biodiversity-from beneficial bacteria to charismatic mammals-threatens human health.

Researchers at the Bard College, New York, found that the loss of species from a range of ecosystems, including forests and fields, could lead to a boost in the transmission of infectious diseases.

They explored the link between biodiversity and infectious diseases such as West Nile virus, Lyme disease and hantavirus.

“We knew of specific cases in which declines in biodiversity increase the incidence of disease,” said lead author Felicia Keesing.

“But we’ve learned that the pattern is much more general: biodiversity loss tends to increase pathogen transmission across a wide range of infectious disease systems,” she added.

The pattern holds true for various types of pathogens - viruses, bacteria, fungi - and for many types of hosts, whether humans, other animals, or plants.

“When a clinical trial of a drug shows that it works. The trial is halted so the drug can be made available. In a similar way, the protective effect of biodiversity is clear enough that we need to implement policies to preserve it now,” said Keesing.

In the case of Lyme disease, strongly buffering species like the opossum are lost when forests are fragmented, but white-footed mice thrive. The mice increase numbers of both the blacklegged tick vector and the pathogen that causes the disease, said co-author Richard Ostfeld.

He however admitted that scientists don’t yet know why the most resilient species - ‘the last ones standing when biodiversity is lost’- are the ones that also amplify pathogens.

The researchers argued that preserving natural habitats was the best way to prevent this effect.

Expanding human populations can increase contact with novel pathogens through activities such as land clearing for agriculture and hunting for wildlife.

Identifying the variables involved in infectious disease emergence is difficult but critical, said another author Andrew Dobson.

“When biological diversity declines and contact with humans increases, you have a perfect recipe for infectious disease outbreaks,” he added.

The authors call for careful monitoring of areas in which large numbers of domesticated animals are raised or fish are farmed.

“That would reduce the likelihood of an infectious disease jumping from wildlife to livestock, then to humans,” said Keesing.

The study is published in the journal Nature. (ANI)