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Deadly parrot virus found in native birds from Asia and Africa

  • Researchers have found beak and feather disease virus (BFDV) in wild parrots from eight new countries.
  • BFDV spreads through captive parrots worldwide, but its prevalence in wild species is unknown. Infected escapees could threaten native parrots, especially small populations.
  • Parrots in West Africa carried viruses that probably spread from other countries, showing that the human pet trade market has made the BFDV epidemic worse.
  • New regulations of live parrot trades are essential to protect susceptible species, researchers say.

Parrots around the globe are captured and sold as pets in a thriving illegal market that has carried more than 19 million birds across borders since 1975. The deadly beak and feather disease virus (BFDV) – which destroys parrot immune systems and causes feather loss and beak defects – can spread worldwide through this lucrative pet trade.

Now, a recent study published in Conservation Biology has documented BFDV in eight new countries in Asia and Africa. The discovery points to grave risks for native species if infected captives escape, especially in isolated populations, researchers say.

BFDV infects captive parrots worldwide and spreads easily among species. However, scientists had a poor grasp of its prevalence in wild populations. Previous studies mostly screened parrots in South Africa, the U.S., or Australia. Other regions with parrots, such as Africa, Asia, and South America, have not received the same scrutiny.

“There is definitely a risk of spillover of BFVD from captive birds into wild populations,” said conservation biologist Deborah Fogell of the University of Kent, U.K., lead author of the study. “A single infected individual that is accidentally or intentionally released can pose a threat.”

BFDV-infected Timneh Grey parrots seized from the parrot trade in Senegal. Photo courtesy of Roman Martin/World Parrot Trust

To help assess the spread of BFDV, Fogell and her colleagues collected blood, feather, and tissue samples from wild and captive parrots in 13 countries. They sampled five species, including the invasive Rose-ringed parakeet (Psittacula krameri), and searched for a telltale genetic imprint of the virus.

The team found infected Rose-ringed parakeets in their native ranges in Bangladesh, Pakistan, Nigeria, and Senegal, as well as infected Grey-headed parakeets (Psittacula finschii) in Vietnam. Invasive Rose-ringed parakeets in Japan and the Seychelles tested positive for BFDV. No previous analyses had detected the virus in these countries.

Sampling locations for parrots screened for BFDV in the study. Graphic from Fogell et al, Conservation Biology (2018).

Researchers also discovered infected captive Rose-ringed parakeets in The Gambia, although their exposure to the virus could have happened earlier since the birds were seized from the wild. Other parrots from the illegal trade in western Africa were infected with viruses related to strains from Taiwan and southern Asia, showing that trading hubs have pooled viruses from all over the world, the authors state.

“We found a lot more BFDV-positive samples than we expected,” Fogell explained, suggesting that humans have brought the virus to new locations.

BFDV-infected Mauritius parakeet. Photo courtesy of Deborah Fogell/University of Kent

With so many viruses from distant parts of the globe in one place, new and more dangerous strains could form. “You’ve got this big melting pot of co-infections,” Fogell said. Parrots can become infected with multiple strains, creating new genetic mixes that could prove lethal for parrots that have never been infected, she added.

The study “certainly confirmed the presence [of the virus] in wild birds, and there have been very few other studies that have done that,” said Shane Raidal, a veterinary pathologist at Charles Sturt University in Sydney, Australia, who was not involved in the study.

Raidal noted, however, that Fogell’s group only analyzed 30 percent of the full genetic sequence of BFDV, which makes it “hard to know the disease ecology of the virus.” He wants to see whole genome sequences from parrots in natural habitats to better understand how the virus is spreading in wild populations.

Rose-ringed parakeets seized from the parrot trade in Senegal. Photo courtesy of Davide de Guz/World Parrot Trust

The study highlights how pathogens are exacerbated by the wildlife trade – and the challenges this poses for conservation, Fogell said. “We are just starting to scrape the surface of pathogens that are being spread globally through human actions,” she said.

Fogell hopes continued surveys of wild parrot populations will lead to stricter international regulations to protect them. Rigorous standards would shield small parrot populations on island nations, such as Seychelles Black parrots, that are not yet infected with BFDV.


Erin I. Garcia de Jesus (@viruswhiz) is a graduate student in the Science Communication Program at the University of California, Santa Cruz. Other Mongabay stories produced by UCSC students can be found here.