Align-ju STUDENT
The fly will lay its eggs on animal skin , often around the perianal area or areas of broken skin such as wounds , as they are attracted by decomposition odours [ 2 ] . Rabbits with diarrhoea or skin conditions are particularly susceptible , often in late spring and early summer [ 4 ] .
The flies usually lay their eggs on faeces or carcasses , but are also attracted to soiled coats , wounds or skin lesions , which create the conditions for facultative myiasis due to the opportunistic behaviour of the fly [ 9 , 10 ] . Some of the risk factors for myiasis are outlined in Table 1 .
Figure 4 . F . subrostratus [ 6 ] .
Treatment
Most flea and tick treatments will eradicate chewing lice infestations . Fipronil , imidacloprid and selamectin are all effective . Pyrethrin powders are also effective if the owner prefers to use powders [ 7 ] . All animals that have been in contact with the host should also be treated and the environment should be cleaned . The treatment may need to be repeated to ensure any hatching nymphs are eliminated . The animals should also be wormed for the tapeworm D . caninum .
Calliphoridae
Flies of the genera Lucilia ( green bottle flies , Figure 5a ) and Calliphora ( blue bottle flies , Figure 5b ) are commonly known as blowflies .
Table 1 . Risk factors for myiasis in rabbits [ 9 ] .
Risk factor Diarrhoea
Urine scalding
Obesity
Wounds
Dirty / humid environment
Reason
Causes moist skin around the anus and provides an ideal environment
Causes moist area and sores around the perianal region and inner thighs
Prevents the rabbit from reaching the perianal region to clean or perform caecotrophy , leading to an accumulation around the anus
Cause broken skin , which provides a site of entry for the larvae
The smell of bacterial decomposition attracts the flies
Dental disease
Pain
Makes it more difficult for the rabbit to perform caecotrophy , leading to an accumulation around the anus
Could restrict the movement of the rabbit . For example , a spinal injury could prevent the rabbit from cleaning itself
Figure 5a . An illustration of a Lucilia species fly [ 6 ] .
Figure 5b . An illustration of a Calliphora species fly [ 6 ] .
Lucilia sericata and Calliphora species flies can cause myiasis in rabbits , also known as fly strike . Myiasis is the infestation of living host tissue by fly larvae . The larvae can feed on dead or living tissue or on gastrointestinal content .
In obligatory myiasis , the fly has to infest a live host as part of its life cycle . In facultative myiasis the fly usually infests carcasses , but it can infest live hosts through a damaged area of skin [ 8 ] .
The larvae ( maggots ) can hatch in as little as 12 hours [ 4 ] , which means rabbit owners should check their rabbit on a daily basis ( preferably twice daily ). The larvae feed on skin debris , exudate from wounds and dead cells , and cause trauma where the larvae burrow into the subcutis [ 10 ] . The larvae moult twice , drop to the ground , pupate and develop into adult flies , which can then re-infest the animal [ 4 ] .
The affected area can expand rapidly as more larvae hatch and feed . Second- and third-stage larvae are more likely to extend the damage to the skin / lesion [ 11 ] . The wound created will attract more flies to the area and further increase the number of larvae .
Volume 39 ( 2 ) • April 2024
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