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ANSWERS
1. Crust can be carefully removed and crushed between microscope slides after
emersion oil has been added. Search for small mites with ‘stubby’ legs.
2.
Knemidokoptes pilae
mite (Figure 3).
3. Separation of those birds infested with this mite since the mite is transmitted from
bird to bird through direct contact.
4. Treatment of choice for birds with scaly leg mite lesions, and all birds that have had
contact with them, is ivermectin. It may require 2-6 treatments at 10 day intervals
to completely eliminate the mites. Ivermectin may be applied to the skin behind the
neck, given orally, or injected. Moxidectin has also been used topically.
Dermatology Quiz
I Answers
A
DISCUSSION
The mites, commonly known as ‘scaly leg mites’ and ‘face
mites’, are parasites of the skin and beaks of birds. The
scaly leg is also referred to as 'tassel foot'. Budgerigars
and many other bird species can be parasitised by
Knemidokoptes
mites that feed on dead skin cells.
K. pilae
dissolves this dead material by means of a keratinase.
K. pilae
are roundish-oval mites (Figure 3). The males
are up to 220 µm long and about 150 µm wide, females
up to 356 µm long and about 300 µm wide. The four
pairs of legs are short and stubby in shape and have five
segments. At the ends of the extremities, males have
unjointed grippers and suckers, while females have claws.
They inhabit a single host throughout their life cycle whilst
infection of a new host occurs by contact. The viviparous
females burrow tunnels in the epidermis where they give
birth to six-legged larvae, which mutate through two
eight-legged
nymphal
stages from
the second
of which
the adults
emerge. In
budgerigars
the eyelids,
beak, cere,
as well as
the legs and
feet can be affected and in severe cases the area around
the bird's vent is affected.
Interestingly, white budgies are albinos. The Ino gene is
responsible for the absence of melanin, so white budgies
are sometimes labelled ‘Inos’.
v
3
Spread of diseases in farmed animals shown using
social network analysis
Researchers have shown that looking at movements of operators and vehicles between farms in
the same way we look at contacts in social networks can help explain the spread of dangerous
infectious diseases of livestock, such as foot-and-mouth disease and avian influenza. This
research, published in
PLOS Computational Biology
, can contribute to the development of more
accurate tools for predicting the spread of livestock diseases and may help implement more
effective biosecurity measures in farms.
The study, by researchers from the Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, has
shown that the network of contacts originated from on-farm visits by veterinarians in dairy farms of Northern Italy
displays hidden features that cannot be detected by simply looking at the frequency of visits and unveils patterns of
infection otherwise unexplained. The authors discovered that veterinarians' movements produce an unexpectedly large
number of potentially infectious contacts between farms that can quickly spread dangerous livestock diseases.
The research, made possible by the availability of high-resolution data in space and time on veterinarian movements in
the study area, shed light on the actual significance of operator movements in disease spread, a still poorly understood
topic due to the highly diverse and complex nature of such movements and to privacy issues in data collection.
The researchers compared the role of veterinarian movements on diseases spread with those of animal exchange
between farms, which is recognised as the most effective transmission route for livestock infectious diseases. They
found that co-occurrence of operator movements and animal exchanges is synergistic, largely amplifying the potential
for disease propagation. The study shows how multilayer network analysis substantially improves the way diseases
spread can be described, thus contributing to their control.
(Source:
www.sciencedaily.com/releases/2017/01/170126142828.htm )v
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