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

35. Mites, lice and fleas
35.1. HAZARD IDENTIFICATION
35.1.1. Aetiological agents
The following from Table 1 Organisms of potential concern have been identified as
preliminary hazards:
Psoroptes ovis (mite)
Microthoracius mazzai, Microthoracius minor, M. praelongiceps (sucking lice)
Vermipsylla spp. (flea)
35.1.2. OIE list
None of these parasites are listed in the Code.
35.1.3. New Zealand status
The mite Psoroptes ovis is the causative agent of the condition ‘sheep scab’ that was
eradicated from New Zealand many years ago (officially declared free in 1893). It is listed
as a notifiable organism (MAF 2009).
No record was found that sucking lice of the genus Microthoracius or fleas of the genus
Vermipsylla occur in New Zealand.
35.1.4. Epidemiology
The mite Psoroptes ovis infests a wide range of host animals including camelids, sheep,
cattle, goats, horses and rabbit. It occurs world-wide and particularly in South America and
Europe. The notable exceptions are Australia and New Zealand that are both officially free.
The lifecycle of Psoroptes ovis from egg to adult takes about 10 days to complete. Larvae
hatch from the egg, moult through two nymphal stages and finally moult to become the
adult form. The mites are non-burrowing and feed superficially on the skin surface. A
hypersensitivity reaction occurs in the host to the presence of the mite. This results in
inflammation and scratching that causes self-trauma to the host and damage to the fleece.
The constant irritation leads to weight-loss and in some cases death of the host (Taylor et al
2007b).
Populations of Psoroptes mites on the host animal decline in warm weather, leaving
residual populations in sites such as the axilla, groin, infra-orbital fossa and inner surface
of the pinna and auditory canal where mites localise (Taylor et al 2007b).
Transmission is primarily through physical contact. However, transmission can occur via
the environment. Survival off the host may be up to 18 days in favourable environmental
conditions of ambient temperatures and high humidity. The potential re-introduction of the
mite into New Zealand could occur through the importation of animals (Taylor et al
2007b).
Treatment of animals infested with Psoroptes ovis is available and effective. These
treatments include pour-on application of organophosphates, synthetic pyrethroids, or the
use of injectable ivermectins (Taylor et al 2007b).
MAF Biosecurity New Zealand Import risk analysis: Llamas and alpacas from specified countries ● 131