Import risk analysis: Llamas (Lama glama) and alpacas (Vicugna ...

producing larvae that move independently about the wound surface, ingesting dead cells,
exudate, secretions, and debris, but not live tissue. This condition is known as fly strike.
Unless appropriate therapy is administered, the infested animal may die, generally from
shock, intoxication, or infection. A distinct, pungent odour permeates the infested tissue
and the affected animal (Merck 2006).
Cephenemyia spp. found in North America are nasal bots of cervids belonging to the
family Oestridae. Reported infestations in camelids are very rare and they are considered
abberant hosts. It is not known if Cephenemyia spp. can complete their lifecycle in
camelids (Wernery & Kaaden 2002).
In New Zealand, Cephenemyia trompe was reported from the nasopharynx of an imported
Canadian wapiti in 1982. This parasite had not been found previously and presumably it
was introduced from Canada, with the wapiti (Mason 1982). Other wapiti from the same
shipment were treated with ivermectin, and establishment of the parasite did not occur.
There have been no further reports of Cephenemyia spp. occurring in New Zealand.
37.1.4.1. Diagnosis
Myiasis is easily diagnosed from a careful clinical examination of the skin, any open
wounds and around body cavities.
Cochliomyia homnivorax (NWS) produces a particularly vile myiasis. Female flies are
attracted to open wounds, and larvae burrow deep into the wound which results in severe
tissue destruction. Infested wounds emit an odour that attracts more flies.
The presence of a superficially situated dermal swelling with a central opening, especially
if more than one is present, may lead to a tentative diagnosis of myiasis due to D. hominis
(Soulsby 1968).
The first indication that an animal is infested with Wohlfahrtia vigil is exudation of serum
and matting of the hair coat over the site of penetration. The presence of a dermal swelling
with a central opening may lead to a tentative diagnosis of myiasis due to W. vigil. On the
third or fourth day, the larvae produce abscess-like lesions. The hair coat often becomes
parted over the summit of the lesions and reveals an opening 2-3 mm in diameter. The
posterior aspect of the larva is visible in these openings, through which it breathes. The
penetration of the skin by the larvae, their development in the subcutaneous tissues, and
secondary bacterial infection produce intense irritation and inflammation (Merck 2006).
Camelids infested with Cephenemyia spp. show clinical signs of head shaking, sneezing
and coughing with or without a nasal discharge. Granulomatous swellings may occur in the
nasopharynx and nasal cavities in chronic cases forcing the animal to breathe through an
open mouth (Wernery & Kaaden 2002).
37.1.4.2. Treatment
Treatment and control measures for myiasis in camelids are limited. With most myiasis
infestations, removing maggots from existing deep tissue pockets may need surgical
144 ● Import risk analysis: Llamas and alpacas from specified countries MAF Biosecurity New Zealand