Leeches have been spreading rapidly in
Ho Chi Minh City
's Hoc Mon District. Locals began breeding them based on demand from
, but dumped them in local fields and other areas after the main buyer closed shop three months ago.
Vietnam's agriculture ministry has issued a ban on the breeding of leeches after large numbers of the carnivorous worms began scaring residents in Ho Chi Minh City, as well as many places in the central and northern regions.
A similar ban also applies to the invasive channel apple-snails (Pomacea canaliculata), as their increasing population is threatening the local ecosystem, said Nguyen Huy Dien, a senior aquaculture official with the Ministry of Agriculture and Rural Development.
He said farmers raised the bloodsucking worms and snails to fulfill orders from China, but the customers have since disappeared.
Both creatures now pose serious threats to local environments. The leeches are being found in all kinds of places, scaring people wherever they appear. The invasive snails - a nemesis of rice and certain vegetables - have been found in large numbers in southern Vietnam.
During a recent encounter with the leeches, hundreds of workers at a HCMC packaging company were hospitalized because they skipped lunch after finding the worms among the dishes served to them.
The incident happened on December 24 when more than 300 workers of the South Korean company Shilla Bags International in Cu Chi District fled their lunch tables in panic after a few leeches were found crawling from the trays.
The company employs nearly a thousand workers and several hundred refused to return to the table after spotting the leeches.
During the afternoon shift, the hungry workers began fainting, suffering from numbness and stomachaches. They were taken to the Cu Chi Hospital and Hau Nghia General Hospital in the nearby Long An Province for treatment.
The leeches made headlines in late November after some Chinese dealers who ordered the worms from farmers across Vietnam failed to show up, leaving thousands of the hardy creatures.
Leeches are (apparently) used for medicinal purposes in China.
Residents in Hoc Mon District have now forbidden children from playing near fields or water for fear of the bloodsuckers.
Locals began breeding the worms for sale to a Chinese medical supply company several months earlier, and stopped in October, when the company's local agent, Kim Anh, closed her shop after receiving a warning from authorities about possible harmful consequences and a recommendation that she cease trading the worms.
Since then, thousands of leeches have escaped or been released into the area, which is rich with overgrown ponds, the worms' favorite habitat. Residents also say Kim Anh's shop had thrown away rejected leeches into the sewers while selecting the creatures for buying, virtually introducing them into the local environment.
Vo Hong Phuc of Hoc Mon District's Tan Xuan Commune said he had settled in the place for four years, but has only seen leeches over the past two to three months.
"They have been breeding very fast," Phuc said. "People have stopped harvesting vegetables or fishing in ponds and other water bodies. Parents have strictly banned their children from playing near the water."
On December 19, police in Tay Ninh Province adjacent to HCMC's Cu Chi District destroyed around 70 kilograms of leeches they seized from a local resident three days earlier. They found the leeches wrapped in seven plastic bags and hidden in a freezer in the house of Huynh Thi Kim Kieu, a resident of Tay Ninh Town.
Kieu told police that Hu Gui Dang, a 42-year-old Chinese trader, collected the leeches from rural districts in the province and stored them at her house before taking them to HCMC.
The presence of such traders prompted many local residents to start breeding the animals after they became scarce in the wild.
Some residents said they had sold leeches to Kim Anh for between VND90,000 and VND150,000 per kilogram a good source of income that is more than a day's work as a hired laborer.
The uncontrolled rise in the population of leeches has raised concerns that they will not only harm crops but also the local ecosystem as a whole.
Dang Huy Huynh, chairman of the Vietnam Zoology Association, said the situation can become a disaster as the farmed leeches will grow to a number beyond the ecosystem's capacity.
Bui Quang Te, an aquaculture expert, expressed similar concerns about the large leech population.
The leeches will suck the blood of other creatures in the same environment and can also spread infectious diseases between animals and people, he said.
He suggested that the creatures be destroyed manually, by catching them and burying them in lime.
Do Thi Thanh Huyen of Wildlife At Risk, a HCMC-based environment group, said several people with the environmental advocacy organization were not so pessimistic about the spreading of leeches.
"As leeches live in the water and feed on hot blood animals that come into contact with the water like humans, poultry, cattle and other small animals, without these sources of food, the leeches will finally die," she told Thanh Nien Weekly.
"It is our opinion that in reality, leeches have become hard to find in many fields, ponds or lakes in Vietnam, due to the use of pesticides and lack of food. Without further adding to natural bodies, these leeches might disappear," she said.
Huyen also said that similar trading activities were taking place with other creatures in Vietnam, and this could have both environmental and economic implications.