parasitic disease Honey bee

Tracheal mite disease

Tracheal mite disease is a parasitic condition of honeybees caused by a microscopic mite, Acarapis woodi. This parasite lives and reproduces inside the trachea (respiratory tubes) of adult bees, not in the brood itself despite the name some...

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Complications When to see a vet Prognosis FAQ Sources Affected species

What is it?

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Irregular or sunken brood Deformed wings Weakened colony Dead bees in front of the hive

The signs are often subtle and non-specific, making diagnosis difficult without laboratory examination.

Bees unable to fly may be observed crawling in front of the hive or falling to the ground.

Some bees show their wings in an abnormal position, dislocated or asymmetrical, giving a deformed appearance.

The colony weakens progressively, with a declining population with no obvious cause, especially after winter.

In advanced cases, many dead or dying bees may be found at the hive entrance.

The brood itself generally remains normal in appearance, because the mite affects adult bees.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The disease is caused by a microscopic mite, Acarapis woodi, invisible to the naked eye. It enters the thoracic trachea of young adult bees, attaches itself using piercing mouthparts, and feeds on hemolymph (insect "blood") by perforating the tracheal wall. Female mites lay their eggs directly in the trachea, where the entire development cycle takes place.

Young bees less than a few days old are most vulnerable to initial infestation. Weakened colonies, those poorly fed, or already stressed by other diseases are more susceptible to the consequences of tracheal mite infestation. High population density in the hive and failure to replace queens regularly also favour internal spread of the parasite. Exchange of beekeeping equipment or colonies between apiaries without health checks increases the risk of introduction.

Transmission

Transmission occurs through direct contact between bees, particularly between young newly-emerged bees that are most susceptible to infestation. Female mites leave an infested bee to join an uninfested bee during close contact within the hive. Bee drift between hives, robbing, and introduction of contaminated colonies promote spread between apiaries.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Definitive diagnosis relies exclusively on laboratory examination. The veterinarian or apicultural technician collects suspected bees, dissects their thorax, and examines the trachea under a microscope to look for the presence of mites or the characteristic damage they cause to the tracheal wall. Direct observation of bees in the hive does not confirm the disease, because the signs resemble other colony disorders.

Treatment

Management relies on specific acaricide products for beekeeping use, applied according to the recommendations of a qualified professional. General strengthening of the colony through good nutrition and overall hive health management supports control of the parasite. No treatment should be applied without advice from a veterinarian or competent apicultural technician, as inappropriate use of acaricide products can cause greater harm to the colony.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

There is no vaccine against this parasitic disease.

Maintaining strong, well-fed colonies limits the impact of the parasite.

Regular queen replacement and selection of tolerant genetic lines help reduce herd susceptibility.

Regular monitoring of colonies, particularly by a trained beekeeper or apicultural veterinarian, allows early detection.

Purchasing colonies or queens from tested sources limits the risk of introducing the parasite into a healthy apiary.

Possible complications

Severe uncontrolled infestation can lead to marked weakening and death of the colony, especially during winter, when bees are already under stress. Tracheal mite infestation can also worsen the impact of other diseases or parasites already present in the hive by reducing the general resistance of the bees.

When to see a veterinarian

Presence of bees unable to fly or crawling in front of the hive.

Abnormally positioned or deformed wings in several bees.

Unexplained and progressive decline in colony population.

Abnormal mortality at the hive entrance, especially after winter.

General weakening of the apiary with no identified apparent cause.

Prognosis

The outlook depends on the level of infestation and how quickly treatment is started. A colony detected and treated early can recover, especially if it also benefits from good sanitary management. On the other hand, a severe infestation that is left untreated, particularly as winter approaches, can result in the complete loss of the colony.

Frequently asked questions

Does acarine brood disease really affect the brood?

No, despite its common name, this disease affects adult bees at the level of their respiratory tracheae, not brood larvae.

Can you see a mite with the naked eye?

No, Acarapis woodi is microscopic and lives inside the tracheas of bees. Only microscopic examination allows it to be detected.

Is this disease dangerous for humans or for honey?

No, it only affects bees and presents no risk to humans or to the quality of harvested honey.

How can I prevent introducing this disease into my hive?

By purchasing colonies or queens from reliable and controlled sources, and by regularly monitoring the health status of your colonies with the help of a professional.