Amid fears that an outbreak of the H7N9 avian flu virus will occur in Taiwan, academics have expressed grave concerns regarding the use of poultry feces as fertilizer, saying it could be a blind spot in epidemic prevention.
Lai Shiow-suey (賴秀穗), an honorary professor at National Taiwan University’s School of Veterinary Medicine, said that birds carrying the virus secrete such high concentrations of it in their feces that 1g of excrement could kill 1 million birds.
“Although the H7N9 virus can destroyed if the excrement ferments at between 70°C to 80°C for a long period of time, unfermented poultry feces could leak during transportation and pose a health risk,” Lai said.
Liu Pei-po (劉培柏), former director of the Taiwan Provincial Research Institute for Animal Health — which became part of the Council of Agriculture in 1999 — said that the H7N9 strain could be spread through birds or flies eating the unfermented droppings of infected chickens.
Academics voiced the concerns following the emergence of 16 laboratory-confirmed cases of H7N9 among humans in China, with six fatalities.
Government statistics show that Taiwan’s approximately 13,000 chicken farms can produce an average of up to 1.12 million tonnes of poultry manure a year.
This substantial production capacity is what lay at the center of a Control Yuan correction issued to the council and the Environmental Protection Administration in July last year, admonishing the two agencies for their improper regulations on poultry feces management and lack of knowledge on how poultry farms dispose of excrement.
According to the correction, current regulations stipulate that only poultry farms with a capacity of 80,000 chickens or above are obligated to report their method for disposing of poultry droppings.
Farms with between 3,000 and 80,000 birds, despite producing nearly 985,000 tonnes of excrement in total each year — accounting for 88 percent of the nation’s total annual output — are exempt from making such reports and only have to adhere to the principle of “self-discipline,” the correction said.
It added that the disposal of poultry feces on farms that housed beneath the minimum threshold of 3,000 chickens went unchecked.
An official from the council’s Agriculture and Food Agency, who spoke on condition of anonymity, said there were several poultry manure suppliers who collect fresh chicken manure and sell it as fertilizer to farmers.
“From my understanding, unfermented chicken manure can be applied as basal dressing to increase the water holding capacity of soil, and is more accessible and cost-efficient than organic fermented fertilizers and chemical fertilizers,” the official said.
Huang Kuo-ching (黃國青), deputy head of the Bureau of Animal and Plant Health Inspection and Quarantine, said that from the standpoint of epidemic prevention, there should be a ban on using unfermented chicken manure as fertilizer.
Animal Husbandry Department Deputy Director Chu Ching-cheng (朱慶誠) said that while no ban had yet been imposed on the reutilization of poultry feces, “the council encourages poultry farmers to let chicken excrement ferment first before it is reused.”