NASAL BOTFLY INFESTATION IN ROE DEER

A roe deer found dead was collected as part of the wildlife disease surveillance program conducted by the Agency for Nature and Forests (ANB) in Flanders. The deer discussed in this case was submitted to the Wildlife Health Ghent (WHG) for necropsy under this surveillance initiative.

Aspirated L3 larvae in the trachea and at the bifurcation of the bronchi in the lungs of a roe deer.

Cephenemyia stimulator , also known as the roe deer botfly, is a parasitic fly that primarily affects roe deer (Capreolus capreolus) and other deer species. The life cycle of Cephenemyia stimulator begins when an adult female botfly lays her eggs near the nostrils of a roe deer. Once the eggs hatch, the larvae enter the nasal cavity of the roe deer and burrow into the retropharyngeal pouch. Here they feed on nasal mucus and other tissues, which can lead to irritation, inflammation, and damage to the nasal mucosa.

The life cycle of the roe deer botfly (from Morrondo et al., 2021).

The presence of Cephenemyia stimulator in the nasal cavity of roe deer can lead to symptoms such as sneezing, shaking of the head and rubbing of the nose against objects. In severe cases, the presence of the larvae can lead to respiratory problems and reduced food intake, which can result in weight loss and general weakness of the animal.

Although infections with Cephenemyia stimulator are usually not fatal for deer, they can cause considerable discomfort and affect the health of the animal. In the past few months, we have received six deer for necropsy, which showed that they had died from inhaling these larvae. The immune system of these animals was probably not resistant to such an infestation, whereby the abundant presence of larvae caused choking problems, resulting in suffocation.

L3 larvae can be seen in the retropharyngeal pouch (A) and nasal passages (B) of the roe deer, as well as sneezed L1 larvae rostral to the nasal entrance (C).

L3 larvae in the retropharyngeal pouch of a roe deer.