Actinobacillosis
Etiology:
Actinobacillus species are non-motile,
gram-negative, rod-shaped bacteria.
These are facultative anaerobes.
Most species are oxidase-positive and
produce urease.
Species of veterinary importance grow
on MacConkey agar.
Actinobacillus lingnieresii cause a lesion in the tongue, lymph nodes, ruminal wall, and skin in cattle.
It is a common inhabitant of the oral cavity
which needs wound or laceration for entry to cause disease.
Pathogenesis:
Bacteria enter through the wound and
cause acute infection at the local site, there is granulomatous lesion formation
with pus discharge, there is the involvement of regional lymph nodes (parotid,
lingual and retropharyngeal). If lesions break under the tongue, the pus goes
down and cause visceral infection.
In actinomycosis, there is no
involvement of lymph nodes while in the case of actinobacillosis, there is
involvement of soft tissue.
Clinical Findings:
Acute inflammation of tongue called
glossitis.
Difficulty in prehension and chewing.
Excessive salivation.
Animals become anorexic for 24-48 hrs.
On palpation, swelling is painful and
is present mostly on the base of the tongue. There is formation of nodules and
ulcers on the dorsum and lateral side of the tongue.
In chronic cases, there is fibrosis of
tongue and its size shrink.
The tongue becomes immovable.
There is inflammation of submaxillary
and parotid lymph nodes thus causing difficulty in swelling.
It is pyogranulomatous
lymphadenitis, and when these granules rupture pus run down and infects the viscera.
There are nasal discharge and snoring
sounds when maxillary lymph nodes are involved.
Granulomatous lesions develop on
external nares, the skin around the nostrils, and on eyelids as well.
In sheep, there is less
involvement of the tongue, the formation of a granulomatous lesion on the face, lower jaw,
from nostrils to the sternum.
Size of granules is about 8 cm,
There is cranial and cervical lymph
node enlargement,
Yellowish green pus discharge occurs,
Difficulty in mastication,
Scabs around lips,
Bilateral nasal discharge and cud
dropping.
Treatment:
Potassium iodide is given per oral;
6-10g daily for 7-10 days in cattle.
Sodium iodide @1g/12kg body weight as
10% solution is injected IV, single dose enough for soft tissue.
If hard tissue is also involved e.g. in
case of actinomycosis, repeat the dose after 15 days.
If there is a high dose, this causes
iodine toxicity which may lead to lacrimation, anorexia, abortion, coughing,
dyspnea, tachycardia, and staggering.
In sheep, a 20 ml solution of sodium
iodide 10% sub-cut is given for 4-5 weeks.
Streptomycin and penicillin the combination is given; 1 g in small animals and 5 g in large animals.
Iodine also causes infertility i.e.
chemical neutering so it should be used more carefully.
