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InFocus

Round-up of the recent literature on parasites

Why, when and how to
control liver fluke in cattle

Andy Forbes, Green End Farm,
Ware, Hertfordshire

The liver fluke (Fasciola hepatica) is
a parasitic condition of increasing
economic performance for the UK
livestock industry.

In cattle, flukes are unlikely to be
a cause of the acute, fatal conditions
seen in sheep but they may be
responsible for three separate health
issues: anaemia, liver damage and
immunomodulation, which may affect
the host response to other pathogens,
such as bovine tuberculosis.

The author reviews the pathology,
impact and epidemiology of fasciolosis
in cattle and offers advice to bovine
practitioners on practical control
strategies. He notes that there is a
relatively small choice of ukicidal
products and several have withdrawal
times that render them difficult
to incorporate into routine farm
management practices.

He suggests that clinicians should
tailor their advice on fluke control
to individual properties, taking into
consideration the farmer’s objectives
and culture, and the need to keep any
recommended actions simple, practical
and economically sound. They are also
reminded of the need to incorporate fluke control within the strategy for
dealing with other major ecto- and
endoparasitic diseases.

Cattle Practice 21 (2): 150-156.

Common misconceptions
held by clients about
heartworm in cats

Kristin MacDonald, VCA Animal
Care Center, Rohnert Park,
California

Many US cat owners believe that cats
kept indoors will not be susceptible
to heartworm infections, unaware that
the mosquito vectors may readily enter
the home. This and 10 other fallacies
that practitioners regularly encounter
were listed in a conference presentation
by the author in Washington DC. She
notes, for example, that many clients
believe that treatment for heartworm
will be the same in cats and dogs.
Meanwhile, with appropriate all-year-
round prophylactic treatment, the
condition is also readily preventable.

Veterinary Medicine 108 (8): 372-373.

Fungal isolates in the
biological control of
gastrointestinal
nematodes in cattle

Manoel Eduardo da Silva and
others, Federal University of
Vicosa, Brazil

Endoparasites are a major constraint
on the development of the cattle
industry in semiarid areas of Brazil.
Due to the problems of drug residues
and increased anthelmintic resistance,
the search is on for alternative worm
control strategies. The authors
conducted trials on the use of two
fungal species, Duddingtonia agrans and
Monacrosporium thaumasium, delivered
twice a week in alginate pellets for
controlling trichostrongylids in
prepubescent ruminant cows. Treated
animals produced fewer eggs per gram
of faeces and there was a significant
reduction in the numbers of infective
larvae on the pasture.

Veterinary Research Communications 38 (2):
101-106.

Guidelines for treating lice
in sheep with long coats to
prevent wool damage

Peri Lucas and Brian Horton,
University of Tasmania

Lice infestations can have serious
implications for wool producers
because of the negative effects on bre
quality and quantity. Traditionally in
Australia, lice treatments are applied
annually after shearing but producers
are now advised to treat only when lice
are detected. The authors developed
guidelines for treatment based on a
model of the development of wool
damage in long-fleeced sheep. The
model identifies the conditions under
which treatment is advisable on an
economic basis and the guidelines can
minimise the net cost of infestation
and limit unnecessary use of pesticides.

Australian Veterinary Journal 92 (1-2):
8-14.

Field efficacy of
eprinomectin against
sucking lice in naturally
infested donkeys

Vincenzo Veneziano and others,
University of Naples, Italy

The sucking louse Haematopinus asini
is a common ectoparasite of donkeys
and other equids which may cause
anaemia, pruritus, loss of body
condition and general debility. The
authors examined the efficacy of
eprinomectin, an avermectin used as
a pour-on treatment for lice in cattle,
to treat naturally occurring H. asini
infestations in donkeys. The agent
was administered at the recommended
dose in cattle of 500μg/kg to 15
animals. No lice were found on
examinations from seven days post-
treatment to the end of the study at
56 days. There was no evidence of
any adverse reactions in the animals
treated.

The Veterinary Journal 197 (2): 512-514.

Diagnosis of giant kidney
worms (Dioctophyme renale)
in dogs

Sheila Rahal and others, Sau Paulo State University, Brazil

The giant kidney worm (Dioctophyme
renale
) is a parasitic roundworm with a
global distribution infesting dogs and
a range of other species, including
humans. Diagnosis is usually achieved
by finding ova in the urine but that
only occurs when gravid female
worms are present in the kidneys.
The authors investigated the value of ultrasonography and computed
tomography in dogs. They found that
both imaging modalities were effective
in detecting D. renale in the kidney but
less useful in identifying parasites in the
abdominal cavity. They warn that there
is a risk of misinterpreting normal
structures as parasites, especially within
the abdomen.

Journal of the American Veterinary Medical
Association
244 (5): 555-558.

In vivo effects of medicinal
plants against gastrointestinal
nematodes in sheep

Mawahib Ahmed and others,
University of KwaZulu-Natal, South
Africa

Resistance to anthelmintic drugs
has become a major problem for
sheep producers across the globe.
The authors investigated the effects
of ethanol extracts of five plants
with apparent medicinal properties:
pineapples (Ananas comosus), Cape aloe
(Aloe ferrox), garlic (Allium sativum),
Chinese bushclover (Lespedeza cueata)
and pepperbark tree (Warburgia
salutaris
). Administered weekly for six weeks, each agent reduced
nematode egg production and infective
larval yields, although there was no
appreciable effect on bodyweight gain.
Continued treatment with these plant
extracts could greatly reduce parasite
burdens and improve host health.

Tropical Animal Health and Production 46
(2): 411-417.

Terbinafine in the treatment
of intestinal Cryptococcus
neoformans
in the dog

Gavin Olsen and others, Iowa State University

Cryptococcus neoformans is a fungal
pathogen that causes diseases of the
nasal cavity, central nervous system,
skin, bone and lymph nodes in various
species. It is only rarely reported as a cause of gastrointestinal disease.
The authors encountered an unusual
presentation in a dog with protein-
losing enteropathy due to C. neoformans
found primarily in the small intestine
and lymph nodes. The case occurred
in a 2.5-year-old intact male vizsla
with persistent diarrhoea, weight loss
and panhypoproteinaemia. Following
surgical treatment to remove damaged
sections of the small intestine, the
condition was successfully treated with
the fungicide terbinafine.

Journal of the American Animal Hospital
Association
48 (3): 216-220.

Kidney function in
canine leishmaniasis
cases following treatment

Marco Pierantozzi and others, Pirani Veterinary Clinic, Reggio Emilia, Italy

Renal pathologies are a frequent cause
of death in dogs with the zoonotic
parasitic condition leishmaniasis. The
authors investigated changes in renal
function in dogs with leishmaniasis
following treatment for four to eight
weeks with meglumine antimoniate and
allopurinol. Urine protein/creatinine,
total protein and total globulin
significantly decreased and both
albumin and albumin/globulin ratio
increased following treatment. They
note that these results may be useful to
clinicians in the clinical management
of canine leishmaniasis in dogs with
proteinuric chronic kidney disease.

Journal of the American Animal Hospital
Association
49 (4): 231-236.

Storage mite
contamination of
commercial dry dog food

Clare Hibberson and Linda Vogelnest, University of Sydney

Storage mites are free-living
arthropods that are implicated in
atopic dermatitis in humans and dogs
both from unique sensitisation and
from cross-reactivity with the more
common dust mite antigens. The
authors investigated samples from
unopened packages of nine brands
of commercial dried dog foods.
Storage mites, identi ed as Tyrophagus
putrescentiae
, were visible in increasing
numbers in seven of nine samples
following incubation under conditions
of moderate temperature and high
humidity. These findings may have
relevance in dealing with cases of
canine atopic dermatitis.

Australian Veterinary Journal 92 (6): 219-
224.

Pharmacokinetics of
albendazole and its
metabolites in laying hens

Mariana Bistoletti and others, UNCPBA, Tandil, Argentina

Increasing problems with roundworm
parasites such as Ascaridia galli are
being reported in poultry housed in
deep litter systems in many countries.
The authors carried out a study to
investigate the plasma disposition
kinetics of albendazole and its main
metabolites when administered orally
and through a single intravenous

dose in laying hens. The study
provides useful information on
the pharmacokinetic behaviour of
albendazole given through different
administration routes. It is an essential
step in evaluating the potential of
this agent in controlling roundworm
parasites in poultry.

Journal of Veterinary Pharmacology and
Therapeutics
36 (2): 161-168.

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