Eating of bone meal and blood meal of infected animals also
Eating of dry fodder or spiky grass produces lesions in
gastrointestinal mucosa, and the chances of infection are
Flies are also a source of transmission.
Its incubation period is 1-2 weeks, some says 7 weeks. Most common
sign of disease is sudden death. There are three forms of disease:
It is most common at the beginning of outbreak. Animals are found
dead without signs. Course of disease is only two hours. Signs may
be fever, dyspnia, congestion of mucosa and muscle tremor and animal
dies after convulsion. After death there is discharge of blood from
natural orifices (mouth, nostrils, anus, vulva etc.).
Course of disease is 48 hours. There is severe depression, increased
body temperature upto 107 oF, rapid and deep respiration,
and congested mucosal lining.
Pathogenic signs are congestion of mucous membrane, hemorrhage from
natural orifices, increased heart rate, animal off feed, ruminal
stasis, abortion in pregnant cows, blood stained or deep yellow
milk, diarrhea, dysentery, and local edema of tongue.
Chronic infection is characterized by localized, subcutaneous,
edematous swelling that can be quite extensive. Areas most
frequently involved are ventral neck, thorax, and shoulders.
It is based on the history of the occurrence of disease in an area,
clinical signs, and necropsy findings. Sudden death in an animal
without prior symptoms should lead to suspicion of anthrax and
bloody fluid exuding from the nose and mouth or anus of living or
dead animal is particularly suggestive of anthrax.
Postmortem is not allowed in case of anthrax. To prepare blood
smear, blood is obtained from ear by giving incision. Blood film
should be dried and fixed by heat or immersion for one minute in
absolute methanol and stained with polychrome methylene blue. Then
it is washed after thirty seconds into hypochlorite solution. After
drying the slide, it is examined under microscope for reddish purple
capsular material and deep blue Bacilli. This reaction is termed as
M- Fadyean reaction.
Because this disease is rapid in onset and with large mortality rate
(90%), this is insufficient to initiate treatment before death. If
anthrax is suspected, segregation of animal should be done. Early
supportive and antimicrobial therapy is useful and Bacillus
anthracis is highly susceptible to a wide range of antibiotics
including benzylpenicillin, tetracycline, and ciprofloxacin. First
dose of antibiotic should be administered intravenously and then
intramuscularly for 5 days. Prognosis is not favourable and no time
to treat the animal.
cattle and buffalo differentiate it from acute fatal blot, per acute
babesiasis, gross tetany, black quarter, acute poisoning, and
enteritis. Anthrax should be considered in differential diagnosis
when an animal dies after having observed apparently good health
during the preceding 24 hours.
Control Strategy for Anthrax:
Control measure is aim to break the cycle of infection. The
important thing is to correct the disposal of carcasses. When an
animal dies inside a shed, paddle or barn, its carcass should be
received for burial or incineration. Plug all the natural orifices
properly before disposing carcass. Burial should be away from water
supply and pasture. The pit should be at least 180 cm deep. The top
layer after burying should be covered with unslacked lime.
Decontaminate the area, bedding, unconsumed feed, and room. Dip the
equipments in 4 % formaldehyde solution for 12 hours.
Veterinary Research Institute (VRI), Lahore has developed anthrax
spore vaccine. It imparts solid immunity for one year. Its dosage in
cattle and buffalo is 1 ml subcutaenously. Vaccination should not be done in
area where disease does not occur. During vaccination one should not
be exposed to vaccine by needle prick.