Sustainable livestock practices for preventing African swine fever

There are multiple strains and various transmission routes

Moreover, African swine fever spreads through many sources, such as direct contact between healthy and infected pigs, pork products, feed, drinking water, waste, tools, vehicles, and even insects carrying the virus. Hanoi currently has a pig herd of about 1.4 million. As of August 20, 2025, the disease has appeared in 35 communes and 222 villages, forcing the culling of 18,193 pigs, equivalent to more than 1,182 tons. Although highly dangerous, African swine fever can be entirely prevented if properly understood.

The virus that causes the disease exists in multiple strains with varying levels of virulence: high, medium, and low. Genetic sequencing results show the circulating strains as follows: 2023: Mainly genotype II, with about 15% genotype I+II. 2024: Mainly genotype II, with about 36% genotype I+II. 2025: Genotype II and about 45% genotype I+II.

According to Mr. Can Xuan Minh from the Hanoi Sub-Department of Livestock, Fisheries and Veterinary, the virus has extremely high resistance and can survive for long periods - up to several months - in manure, dead pigs, and pork products (such as frozen meat, smoked meat, or undercooked meat). The colder the temperature, the longer the virus can persist, especially in raw pork or meat cooked at low temperatures, where it can survive for 3–6 months. It can be inactivated at 56°C for 70 minutes or at 60°C for 20 minutes.

The virus can remain viable for: 15 weeks in decomposed blood, nearly 70 days in dried blood, 11 days in feces at room temperature, 18 months in pig blood stored at 4°C, 150 days in bone-in meat at 39°C.

However, the virus can be destroyed using certain veterinary disinfectants such as ether, chloroform, and iodine compounds, or by applying sodium hydroxide at a ratio of 8/1,000, formalin at 3/1,000, bleaching agents containing 2.3% chlorine hypochlorite or 3% ortho-phenylphenol (with at least 30 minutes of exposure), and lime powder.

There are many transmission routes in pigs, such as healthy pigs coming into contact with infected pigs, or exposure to the blood, feces, and secretions of infected animals. Healthy pigs can also become infected by eating leftover food from humans (restaurants, hotels, industrial zones) that has not been properly cooked. They may also contract the disease through contact with contaminated vehicles, farming equipment, feed packaging, farmers’ clothing, water sources, or insects carrying the virus.

One factor contributing to the rapid spread of the disease is the hurried sale, slaughter, and transport of infected pigs or pork products, as well as the handling of diseased or dead pigs without proper disinfection, allowing the virus to cling to clothing, boots, or shoes. Fortunately, the virus does not infect or cause disease in humans.

Prevention protocol

Understanding the virus and its transmission routes allows farms to prevent African swine fever by strictly following these measures: First, strictly control the movement of people and animals in and out of livestock areas. Pigsties must be designed to facilitate cleaning, disinfection, sterilization, and disease prevention. They should also be surrounded by netting to block insects and intermediate hosts such as rats, birds, flies, and mosquitoes.

Disinfection pits must be installed at the entrance to the pigsty, and protective clothing should be changed for anyone entering or leaving. A separate isolation pen should be available for newly introduced pigs or sick pigs. There must also be designated areas for collecting and treating waste. The wastewater system from the pigsties to the treatment area must be sealed, with each pen having a separate outlet leading to the main drainage system.

Second, newly introduced pigs must have a clear and healthy origin; if brought in from another province, they must have a veterinary quarantine certificate and be kept in isolation for at least two weeks.

Third, only feed with a clear origin, guaranteed quality, and safety should be used. In cases where leftover food is used, it must be heat-treated before feeding. Leftover feed from pigs already sent to slaughter or from herds previously infected must not be given to new pigs. The water supply for pig farming must be safe. Supplementary feed with probiotics is recommended to improve digestion and boost pigs’ immunity.

Fourth, apply the “all-in, all-out” management method, prioritizing by row of pens or individual pens. Establish appropriate farming procedures for each pig type according to its growth and development stage. It is recommended that dry farming methods be adopted, avoiding bathing pigs with water. Use probiotics in drinking water, bedding, and conduct periodic mist spraying inside the pigsties as instructed by manufacturers to strengthen disease prevention and control.

Fifth, strictly limit outsiders’ access to the pigsty area. Before entering and after leaving, workers must change protective clothing, disinfect their hands, and dip their boots or shoes in disinfection pits. Disinfectant in pits at the entrances of farming areas and pigsties must be replenished or replaced daily, and different types of disinfectants should be alternated to improve effectiveness.

Spray disinfectants regularly around the farming area and pigsties, clear bushes, and clean and unclog drainage systems outside the barns. Feeding and drinking troughs must be cleaned daily, and equipment, tools, and vehicles used in farming must be disinfected frequently.

After each production cycle, pigsties and farming equipment must be cleaned and disinfected, and the pens should be left empty for at least 7 days before reintroducing pigs. In the event of an outbreak, restocking should only take place after leaving the pens empty for at least 30 days and with approval from local authorities.

Sixth, control transport vehicles, equipment, and farming tools. Vehicles like motorbikes, bicycles, carts, or hand-pulled trolleys must not be kept inside pigsties. Any vehicle entering or leaving the pig farming area must be disinfected. In particular, traders’ transport vehicles or feed delivery trucks must not be allowed inside the pig farming zone. These vehicles should stop outside for cleaning, disinfection, and sterilization, while internal farm vehicles are used for transport. It is recommended to use dedicated transport vehicles, and if sharing is necessary, they must be thoroughly cleaned and disinfected before use.

Finally, collected waste must be kept far from pigsties and water sources, transported to centralized treatment sites, and processed by heat, chemicals, or appropriate biological methods. Solid waste must be treated hygienically in compliance with veterinary regulations before being taken outside. Liquid waste must be discharged directly from pig pens to treatment areas through separate drainage systems.