10/04/2022
FACTORS TO KNOW ABOUT POULTRY MITES AND IT CONTROL.
Poultry red(PRM, Dermanyssus galline) and Northern fowl mite (NFM, Ornithonyssus sylvarium) are a major concern for health and welfare of laying hens in many areas of the world and have a huge economic impact for egg producers.
Both are small ectoparasites but while NFM completes it's entire cycle of bird, PRM are only found on the host when feeding blood, during the dark period, and spend the majority of it's lifecycle in cracks and crevices, where female lay the eggs. Lifecycle is very short under favorable condition the PRM total cycle can be completed within seven to ten days and even less for NFM.
Transmission by contact with infested bird inanimate object (crates, egg trays) or personnel.
PRM show higher resistance to starvation than NFM, and they can survive beyond 8 months without a blood feed this make unlikely total removal of mite at cleaning and disinfection, then infestation in subsequent flock is common.
CLINICAL SIGNS
Infestation by mites has negative consequences not only in the welfare of the birds, but also in the economic performances of the flocks due to production losses and treatment cost. High stress in birds, resulting in altered behavior such as👉nervousness, feather pecking and cannibalism, floor eggs, smothering, weakness, weight loss, increase sensitivity in pathogens, anemia and significant mortality in severe cases. Decrease egg production, reduce egg weight and increase FCR.
IMPACT ON EGG QUALITY
weaker eggshell, blood stained eggs and even paler shell color.
NFM are frequently found in the vent area, producing dermatitis and scabs.
Red mites are also vectors of poultry pathogens like Newcastle disease virus, fowl pox virus, salmonella app and others.
CONTROL
Mites control must be extensive: complete eradication is very difficult, and when bird are in lay, few active products are available in many countries because of pesticides regulations, so the objective is to reduce the risk of initial infestation by👉 maximizing control efforts in the period when the house is empty. Once the flock is depleted, control should start with thorough cleaning (inside and outside the house) and removing or sealing any obvious refuges. When the house is dry, an approved chemical acaricide should be sprayed, focusing on cracks and crevices. Products rotation is recommended to reduce the risk of mites developing resistance to available chemicals.
Other methods have shown to be effective,like the house above 45°C, but it's costly and usually detrimental for farm equipment. Using mineral oils or biodiesel is also an option, having a suffocating action on mites.
Basics biosecurity and hygiene rules should be followed once the replacement flock is housed. Monitoring of the presence of mites on a weekly basis is crucial, commonly installing "traps" for PRM randomly in the house (corrugated cardboard rectangle, PVC tube, scotch tape) and examining vents for NRM, so early spot treatments can be used to limit their proliferation.
Chemicals used for classical spraying treatment are 👉 organophosphates, carbamates and pyrethroids, but their use in presence of birds is limited in many countries due to health issues and linked due to residues in animal products. New registered parasiticide are currently available👉 (spinosyns, isoxazolines) some to be used via drinking water.
The alternative methods of control are based in different of different types of action, some of them are already available but others, although promising, are still at experimental stages.
Cyclical lighting programs: they help to reduce the mite population, but they are not allowed in some countries by animal welfare legislation. Desiccating products (silica, clay, fossil diatoms): powders having a mechanical or physical action on mites leading to dehydration of the parasite.
Plant extracts: mostly essential oils, some of them have proven to be toxic to red mites.
Predators: biological control methods based on used of natural enemies of red mites.
Wish you well on your flock farming business. Good luck.
Written by Dr. Noor