Poultry production: Keep highly pathogenic avian influenza out of your poultry

Act immediately and implement practical rules and procedures that help to keep viruses at bay during an outbreak of avian influenza.

A strain of the highly pathogenic avian influenza (HPAI) virus – H5N8 – is currently having a field day in South African poultry systems where it is causing serious damage in the sector.

It seems possible that the virus, also referred to as bird flu, came into the country from Zimbabwe, where thousands of chickens have been culled. Neither Zimbabwe nor South Africa has any previous history of outbreaks involving this specific strain of HPAI.

If you look at the disease event timeline it is obvious that HPAI has moved with frightening speed from the north to the south of the country. Wild birds and waterfowl have tested positive for H5N8, as well as poultry on commercial layer and broiler farms.

In South Africa, farmed poultry that tests positive for HPAI is culled and buried in limed trenches. This is a good route to take everywhere the disease occurs, because it prevents further spread from dead birds.

Free-ranging, scavenging and roosting is not an option during a lethal virus outbreak. Poultry is protein on the move and an important addition to the diet. Farm to protect your resource; farm without excuses and make a plan.

GATEWAYS FOR THE BIRD FLU VIRUS

HPAI thrives in the poultry house ecosystem, where it is more moist and perhaps a little warmer. Airborne viral transmission is possible inside chicken housing, but not outside, so it’s important not to overcrowd your chicken houses.

On the other hand, birds in houses are contained, whereas many domesticated birds in the region are left in open coops and scavenge and roost where they please, increasing the risk of infection from wild birds via their droppings.

Sick birds infect healthy birds through secretions from the nasal openings, the mouth, the eyes and infected faeces. The easiest way for the virus to be transmitted is through the movement of sick, live birds and the contaminated vehicles and cages that contain and carry them.

Once the virus has a foothold, it can use virtually any moving object or animal to spread from farm to farm. Animals, birds, vehicles, feed deliveries, boots, clothes, feed, litter and water. Another common-sense tip – don’t feed chicken litter to any animals during an HPAI outbreak.

IDENTIFY THE DISEASE

Watch out for unexplained deaths in your flock. HPAI may present with diarrhea, appetite loss, respiratory problems like coughing and sneezing, blue discolouration on the neck and throat, and egg losses.

Keep scanning your birds for problems and don’t drop your guard when you have a lethal virus like this in your region just.

IMPLEMENT THE RULES

Selling live birds on open markets is the kiss of death during a bird flu outbreak. You can sell birds and eggs from the farm gate, as far from the poultry areas as possible, but certainly 50 m away.

The same principles apply whether you have a starter group of 20 chickens or a commercial chicken house. In both operations you stand to lose all your animals if you are not strict about keeping your farm secure from disease.

Rule 1: Keep people and vehicles off your farm as far as it is possible. If your enterprise takes regular deliveries of feed and bedding from transporters, have them make the drops at the gate.

In the case of essential service providers and your workers, set up a protocol at the entrance to your farm to minimise risks of transmission. It’s best for them to strip off outside clothes and put on clean overalls and boots before entering the poultry area.

Use a viricide (like Virbac) to get any possible contaminants off boots and shoes, and spray your own vehicle’s tyres with the product every time you leave or go back onto your farm.

Lock the gates, keep the vehicles out, keep the people out, set strict rules for disinfection of workers and farmers, and shelter the birds from outside contact with wild birds. Isolation and segregation are the most effective acts against the spread of viral disease.

Rule 2: Keep chicken houses and all the associated equipment clean and disinfected. Diligent cleaning of all surfaces can go a long way to keeping viruses out of your protected zone. Use a good disinfectant and a scrubbing brush and keep up your cleaning routines daily on every possible item that can carry organic material.

Restrict movement of backyard and village chickens by putting them into a chicken coop with netting on the top to exclude contact with wild birds. If you cannot confine your chickens and there is an outbreak of HPAI in your area – sell your chickens before the disease gets into your flock and start again when the danger is past.

Keep all your water and feed containers clean and monitor the quality of the water and feed daily, twice daily or even three times daily. The smaller your flock, the easier it is to keep control.

Rule 3: Run an all-in all-out system. Don’t bring new birds into an existing flock and sell all of your chickens at the same time. This makes it easier to clean and disinfect the poultry zone between flocks.

If you are selling birds from a small operation at your farm gate, try to stick to the principle of selling off an age group and then breeding up again.

Rule 4: Keep your flock healthy. Healthy birds have better resistance to disease. If nutrition is poor, access to clean water is patchy and birds are unvaccinated against other diseases (like Newcastle disease) the chances of a disease infecting the flock are greater.

Farming through a viral epidemic is tough. The way to survive is to implement tough measures and stick to them.

 

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