DERMATOPHYTOSIS in guinea
pigs is:
n Almost invariably due to Trichophyton
mentagrophytes. Rarely Microsporum spp
and Trichophyton verrucosum.
- More common in young guinea pigs
and those sourced from inferior outlets
where stressors such as poor
husbandry, inadequate nutrition, high
environmental temperature and
humidity favour infection.
Clinical signs
- Non-pruritic scaling and alopecia on
the nose and face, which may spread
elsewhere in severe cases. In those cases
secondary infection frequently occurs
associated with pruritus, erythema,
crusts, pustules and papules. - Guinea pigs may be presented with
no signs but with a diagnosis of
ringworm in a family member,
frequently a child.
Diagnosis
- Trichophyton mentagrophytes does not
fluoresce under the Wood’s lamp.
n Epilation of hair from the periphery
of the lesion and mounting in liquid
paraffin. Check for arthoconidia on the
exterior of the hair shaft - Fungal culture is advisable to
confirm as the condition is a zoonosis. - Hairs on the periphery of lesions,
with crusts and scale from the centre,
can be inoculated on to dermatophyte
test medium or sent to a specialised
mycological laboratory. - McKenzie brush technique should be
used to identify carriers, especially if
human contagion is suspected. Use a
sterilised toothbrush (a new one is
satisfactory) and brush the entire
animal, including the facial area in
particular, and then inoculate on to the
medium. - Carrier status is thought to be
common. There are a few publications
that substantiate this statement. Vangeel
et al 2000 (3.4% carrier status in healthy guinea
pigs) and
more
recently
Kraemer
et al 2013 (8.5% carrier status).
Treatment
- No products are licensed for the
guinea pig. Informed consent is
necessary. - Affected animals plus all in-contacts
should be treated. - Topical. The following have been
recommended: 2% miconazole
(Daktarin) cream applied daily, 0.2%
enilconazole (Imaverol) dip, 2%
chlorhexidine + 2% miconazole
shampoo (Malaseb), 2% lime sulphur
dips (Lime plus) all applied weekly. - Systemic. Itraconazole (Itrafungol)
5mg/kg/day. - Treatment should be continued until
the guinea pig is clinically normal
followed by a negative fungal culture
using the McKenzie brush technique. - Environmental decontamination –
0.2% enilconazole, bleach for hard
surfaces.
Further reading
- Kraemer et al (2013) Clinical signs, therapy and
zoonotic risk of pet guinea pigs with
dermatophytosis. Mycoses 56 (2): 168-172. - Kraemer et al (2012) Dermatophytes of pet
guinea pigs. Veterinary Microbiology 157 (1-2):
208-213 – 8.5% of healthy guinea pigs carriers. - Vangeel et al (2000) Prevalence of
Dermatophytes in asymptomatic rabbits and
guinea pigs. Vet Rec 146 (15): 440-441 – four
from 115 sampled were carriers, 3.4%.
