US authorities are continuing to allow imports of long-tailed macaques from Cambodia, despite revelations that deadly pathogenic agents, including one deemed to be a bioterrorism risk, are entering the country with primates and recent charges of illegal trafficking of wild macaques falsely labeled as captive-bred into the US biomedical industry from Cambodia.
Animal rights campaigners are urging the US government to stop the “cruel trade”, saying it’s impossible to prove provenance and that the risk of disease is significant.
“The monkey trafficking trade is a substantive threat to public health, it’s only a matter of time before a recognized or novel pathogen sparks a new pandemic. The CDC is meant to be protecting the public, not bringing diseases into the country, jeopardizing public health,” said primatologist Dr Lisa Jones-Engel.
Sources confirm that 720 long-tailed macaques were transported on a Maleth-Aero flight leaving Cambodia on 28 December and arriving in Dulles, Washington, a day later. About 360 primates were then transported by road to Charles River Laboratories in Houston, a large US importer and user of primates.
It’s unclear where the remaining 360 macaques were transported to.
Charles River has previously stated that they may import animals “carrying infectious agents capable of causing disease in humans”. Charles River did not respond to requests for comment.
Documents obtained by Peta and revealed by the Guardian showed highly pathogenic agents entered the US with monkeys imported from Asia between 2018 and 2021, including at least six cases of Burkholderia pseudomallei in macaques from Cambodia.
B Pseudomallei causes melioidosis, a rare but fatal disease in humans and is a tier 1 select agent with potential as a bioterrorism weapon. B Pseudomallei was, for the first time ever, detected in soil and water in Mississippi in 2022.
In November, the US Department of Justice charged two Cambodian officials, including Cambodia’s second-highest-ranking wildlife official, Masphal Kry, and the owner of Vanny Bio-Research, a Cambodian macaque supplier, with illegal trafficking of wild macaques into the US research industry.
The justice department alleged that more than 14,000 wild macaques were trapped, falsely labeled as captive bred at Cambodian monkey farms and 3,000 were exported to the US. The indictment includes two unnamed US co-conspirators in Alice, Texas, and southern Florida.
Cambodia is the world’s largest exporter of macaques, and the main supplier to US laboratories, exporting 19,269 in 2021 to the US.
Sarah Kite of Action for Primates said: “No one can guarantee any of the monkeys imported from Cambodia are not wild-caught, especially when the allegations are of corruption at a government level and involve the wildlife department responsible for issuing export permits for the macaques to be sent to the US.”
Dr Cindy Buckmaster, who has worked in animal research for over 25 years, said: “I don’t know what we can do – the animal research community can’t tell if they’re fudging the paperwork, and it’s the animals who pay the price.”
The US Fish and Wildlife Service did not respond to requests for comment.
The primate shipment from Cambodia took at least 48 hours. During transportation, monkeys are kept in small crates that prevent normal posture, enduring loud noises, inadequate ventilation and temperature fluctuations. The Maleth-Aero flight had a five-hour stopover in Georgia, and a dramatic drop in temperature from 87F (30.5C) in Phnom Penh to 40F in Tbilisi.
Kite said: “It’s not possible to confine primates and transport them on long journeys across the world without causing considerable suffering. Some may become ill or die in transit. For others, stress may lead to disease which can remain latent until the animals reach their destination or become ill during quarantine.”
There is concern that an increase in diseases found in primates at US quarantine facilities may be due to an increase in illegally caught wild monkeys being mixed in with farmed primates in Cambodia.
Documents obtained by Peta reveal that primates who died in quarantine rose from 29 in 2017 to 125 in 2021 and those that were ill in quarantine but recovered increased from five in 2017 to 119 in 2021.
Jones-Engel, Peta senior science adviser, said: “Since 2019, the CDC has overseen the importation of nearly 100,000 long-tailed macaques and the agency’s own documents make it clear that many monkeys arrived and were moved throughout the US with pathogens in their bodies. Melioidosis can be introduced and persist in the soil and water, posing a serious danger.”
Primates imported to the US are held in CDC-mandated quarantine facilities for 31 days during which time they are tested for infectious diseases.
A CDC spokesperson said: “CDC requires NHPs [non-human primates] having suspected or confirmed infectious disease of public health concern during quarantine to be appropriately treated and clinically healthy (as attested to in writing by the importer’s veterinarian) before the CDC will authorize release from quarantine.”
The CDC spokesperson continued: “If something like melioidosis is identified in an NHP following the CDC-mandated quarantine, state and federal partners collaborate in investigations to protect public health.”
Long-tailed macaques have suffered intensive capture for research for over fifty years, and are now an endangered species. Malene Friis Hansen, director of the Long-Tailed Macaque Project, said: “The demand coming from the US research industry seems to be driving the trade to an unsustainable level.”
Charles River warned investors of disruption to primate imports from Cambodia further to the smuggling scandal, and the biomedical community said delays could slow down vaccine and medical progress.
However, studies show that primates are poor predictors of results in humans, and long-tailed macaques are rarely used in vaccine development, but are instead the “go-to primate” for toxicology testing.
In response to failing animal models, in December, US Congress passed the FDA Modernisation Act 2.0, which removes the mandate for pre-clinical tests in animals before human trials, paving the way for routine use of “human relevant” technologies including organ-on-a-chip and computer models that are more predictive of human response to drugs than animal tests.
