Detailed Clinical and Pathological Characteristics |
| General |
Anthrax
is characterised by its sudden onset and the rapid development of fatal
septicaemia. (B58.25.w25,
B209.23.w23, B336.67.w67)
|
Clinical
Characteristics |
- The clinical forms of the disease range from peracute to chronic. (B101,
B58.25.w25, B209.23.w23,
B336.67.w67)
- The peracute form is characterised by sudden death; in some cases
dyspnoea, convulsions and collapse is recorded. This form is seen
particularly in cattle, sheep, goats and wild herbivores. (B101,
B58.25.w25)
- Terminal opisthotonus and rigid extension of the forelegs. (J64.21.w21)
- The course of the clinical disease is less than two hours in
peracute cases and under 72 hours in acute cases. (J64.21.w21)
- The acute form is characterised by a period of sudden onset fever and
excitement followed by depression, respiratory and cardiac
distress, exudation of blood from body orifices in some cases,
convulsions and death. (B101,
B58.25.w25)
- Depression, weakness, difficulty walking, staggering,
swelling of the umbilical region/prepuce. (J64.21.w21)
- Carnivores, suids and low-grade immunised animals often show
subacute to chronic disease, with three days or more from first
signs to death or recovery. (B101,
J64.21.w21)
- The chronic form is characterised by localised subcutaneous
oedema:
swellings of the face, throat, neck, and/or ventral body. (B101,J64.21.w21)
- This may remain localised. If infection progresses to
septicaemia the diseases is normally fatal. (J64.21.w21)
|
| ELEPHANTS |
- Sudden death. (B64.27.w4,
B212.36, B214.3.7.w3, J3.26.w1,
J3.76.w4, J66.65.w1, P64.1.w3, P502.1.w5)
- Shivering. (P64.1.w3,
P502.1.w5)
- Anorexia. (B64.27.w4,
J3.76.w4,
J3.114.w8)
- Fever.
(B64.27.w4, J3.76.w4)
- Cyanosis (blue mucous membranes). (J3.76.w4)
- Respiratory distress. (B212.36)
- Lateral recumbency. (J3.114.w8)
- Haemorrhages visible on mucous membranes. (B64.27.w4)
- Signs of abdominal pain. (B64.27.w4,
J3.114.w8)
- Colic. (B64.27.w4,
B212.36, B214.3.7.w3)
- Haemorrhagic diarrhoea.
(B64.27.w4, B212.36)
(associated with colic). (B212.36)
- Dull/listless, with hanging head and trunk. (J3.76.w4)
- Excessive lacrimation.
(J3.76.w4)
- Restlessness. (J3.133.w3)
- Weakness of the hindquarters, with frequent falls. (J3.133.w3)
- Nervous signs including spasms, excitement or listlessness,
locomotor problems paralysis and convulsions leading to death. (B212.36)
- Cutaneous form: fever, rapidly-forming subcutaneous swellings which
are initially hot, painful and doughy but later become cold and
painless. Incision shows the contents to be jelly-like, not pus. These
are found most commonly behind the jaw, between the limbs, in the
groin, on the front of the shoulders, on the abdomen or on the hind
quarters. Sometimes, sores develop on the skin. (B212.36)
- In two female Elephas maximus
- Asian Elephant in London Zoo in 1926, initial
shivering general malaise and decreased interest in food. In one case
illness progressed to recumbency by 36 hours after the onset of signs
and death by 48 hours. In the other, stimulants produced an apparent
transitory improvement but death occurred two days after the onset of
illness. (J46.1927.w1)
- One female Loxodonta africana
- African Elephant at Chester Zoo in 1964, appeared tired, sat
down, appeared weak, then died quietly in a sitting position. Two
others were apparently well and eating normally in the evening but
were found dead less than 12 hours later. (J3.76.w4)
- One young female Elephas maximus
- Asian Elephant at Chester Zoo developed a high temperature
(103-105 °F), was dull and anorectic, with her head and trunk
hanging, excessive lacrimation, swollen and bluish conjunctiva (mucous
membranes) and clearly audible heart sounds. (J3.76.w4)
Descriptions of several individual cases are available in: B212.36
- Elephants and their Diseases
- Part V Infectious Diseases Chapter III - Anthrax. Full text included.
|
| WATERFOWL |
- Sudden death or signs of
septicaemia (B14,
B16.19.w1).
|
| BEARS |
- In one Ursus maritimus - Polar bear,
during an outbreak of anthrax at Chester Zoological Gardens, UK,
unilateral submaxillary swelling was seen. (J3.92.w3)
- In a bear (species not specified), signs were non-specific: initial
refusal of food, although it could be tempted to eat a little, and
generally off colour (temperature 38.7 °C). The following morning it
was much worse, recumbent, with reduced body temperature (36.6 °C).
It was treated with fluids and appeared a little better by evening,
body temperature was 37.5 °C. However, the following morning it was
found dead. (J142.19.w1)
|
Incubation |
- Three to seven days. (B101)
- Probably 1-14 days. (J64.21.w21)
|
| ELEPHANTS |
--
|
| WATERFOWL |
--
|
| BEARS |
--
|
Mortality / Morbidity |
--
|
| ELEPHANTS |
Elephas maximus
- Asian Elephant
- Fourteen of 21 clinically affected individuals,
out of a group of 58 elephants, died. (J12.4.w1)
- Two of seven elephants were affected and both died, in London Zoo in
1927. (J46.1927.w1)
- One individual case at Kerala. (P64.1.w3)
Loxodonta africana
- African Elephant
- A surveillance study in Etosha National Park,
Namibia, 1975-1990, recorded a higher incidence of elephant mortality
due to anthrax during the dry season than during the wet season. (J64.12.w2)
|
| WATERFOWL |
-
Disease reported
occasionally (B16.19.w1, B32.14.w21).
|
| BEARS |
- Reported rarely (only two cases reported). (J3.92.w3,
J64.21.w21, J142.19.w1)
|
Pathology |
Gross pathology:
- Note: The carcass of an animal dead of suspected anthrax should
NOT be
subjected to post mortem
examination, as a precaution against contamination
of the environment. (B101,
B212.36)
- General:
- Rigor mortis is commonly absent or incomplete. (B101,
B58.25.w25, J64.21.w21)
- Commonly opisthotonus and rigidly extended forelegs. (J64.21.w21)
- Exudation from body openings of dark red blood that clots poorly. (B101,
B58.25.w25, B209.23.w23,
J64.21.w21)
- Bloat and quick body decomposition. (B101,
B58.25.w25)
- Subcutaneous oedema. (B209.23.w23)
- Blood-tinged fluid in the peritoneal, pleural and pericardial
cavities. (J64.21.w21)
- Haemorrhages
are common
in subcutaneous tissue and on the serosal
surfaces of the abdomen and thorax. (B209.23.w23)
- Enlarged and congested lymph
nodes. (B58.25.w25,
B209.23.w23)
- Pathological lesions are consistent with septicaemia. (B336.67.w67)
- Splenic: grossly enlarged, dark and soft (pulpy) spleen. (B101,
B209.23.w23, J64.21.w21)
- Characteristic, but nor present in all cases. Rare in sheep,
horses, pigs, impala. (J64.21.w21)
- Respiratory: Congestion (B58.25.w25),
oedema . (J64.21.w21)
- Cardiac: petechiae and
ecchymoses
on the epicardium and
endocardium. (B209.23.w23)
- Hepatic: liver congested. (J64.21.w21)
- Pancreatic: Congestion of the pancreas. (J64.21.w21)
- Renal/Urinary: kidney and urinary bladder congested .(B58.25.w25)
- GIT: The intestinal mucosa is haemorrhagic and may be ulcerated. (B58.25.w25,
B209.23.w23)
- CNS: vasogenic oedema of the brain. (J64.21.w21)
In carnivores:
- Head, tongue, throat: sever inflammatory oedema. (J64.21.w21)
- GIT: severe inflammatory oedema of the stomach and intestines. (J64.21.w21)
|
| ELEPHANTS |
-
DO NOT conduct a post mortem examination if anthrax is
suspected. (B101,
B336.67.w67, J64.21.w21)
- Prior to starting the examination, make a blood smear and
examine it to check for anthrax. (D286.2.w2)
Gross Pathology:
- External features:
- Bloody discharge from natural orifices is common. (B212.36)
- The abdomen is often swollen. (B212.36)
- Subcutaneous swellings may be evident. (B212.36)
- Poor blood clotting. (J3.114.w8)
- Blood is usually dark, tarry and fluid. (B212.36)
- Dark, viscid blood. (J46.1927.w1,
J388.1927.w1)
- In a female Loxodonta africana
- African Elephant at Chester zoo in 1964 it was noted that the
blood was not dark and tarry or viscid, but was
"bright red and flowing freely." (J3.76.w4)
- Serohaemorrhagic exudates (blood-stained fluid) with fibrin in the thoracic and abdominal
cavities. (B212.36,
J3.133.w3)
- Haemorrhages may be noted on all serosa. (B212.36)
- Subcutaneous masses, described as "jelly-like" and considered
characteristic of anthrax. (B212.36)
- Skin: A single scab-covered sore was found on one elephant at
London Zoo in 1927; huge numbers of anthrax-like bacilli were found in
a smear taken from this sore. (J46.1927.w1,
J388.1927.w1)
- Heart:
- Haemorrhages of the epicardium and atrioventricular
surface. (J3.133.w3)
- Blood-splashing on the endocardium. (J3.76.w4)
- Lungs: May be severely congested and swollen. (B212.36)
- Gastro-intestinal:
- Extensive petechiation of the serous intestinal surface. (J3.114.w8)
- Intestinal ecchymoses. (J3.133.w3)
- Ulcerated small and large intestine. (J3.133.w3)
- Liver: Enlarged and congested. (B212.36,
J3.133.w3)
- Spleen: Dark in colour and grossly enlarged. (B212.36,
J3.114.w8)
- In two female elephants at London zoo, the spleen, although dark
and congested, was not grossly enlarged. (J46.1927.w1,
J388.1927.w1)
- Bladder: Haemorrhages. (J3.133.w3)
- Lymph nodes:
- Enlarged, oedematous and
congested mesenteric
lymph nodes. (J3.114.w8)
- Mesenteric lymph nodes slightly haemorrhagic. (J3.76.w4)
- Brain: Congested meninges with dilated vessels. (J3.133.w3)
- Note: typical lesions are not always present. In a female Loxodonta africana
- African Elephant at Chester zoo in 1964, the blood was bright
red and freely flowing, the abdominal organs appeared normal, with no
inflammation of the intestines, no enlargement of the spleen, sharp
borders to both the liver and spleen, normal-appearing lungs and pleura.
The only lesions noted were blood-splashing on the endocardium and
slightly haemorrhagic mesenteric lymph nodes. (J3.76.w4)
A description is available in Elephants and their Diseases- A Treatise on Elephants - Part V - Chapter III
- Anthrax. Full text included.
|
| WATERFOWL |
Liver, spleen and kidneys
enlarged, haemorrhagic lesions throughout the body (B14). |
| BEARS |
In one bear (species not
specified), necropsied a few hours after the bears was found dead: (J142.19.w1)
- General:
- Carcass in good condition, although a little distended.
- Subcutaneous tissues dilated with liquid blood.
- In the abdominal cavity, about one litre of clear, slightly
reddened fluid.
J142.19.w1
- GIT:
- Gastric mucosa very hyperaemic.
- Intestinal mucosa, about 10 m also haemorrhagic.
- Spleen: not enlarged, blue-grey in colour, medium
consistency, with a small quantity of dark red thickened blood.
- Liver: enlarged, yellow-brown with rounded edges and
friable (as if cooked).
- Renal: congested kidneys; a little reddened urine was
present in the bladder.
- Cardiovascular:
- A little reddish fluid was present in the pericardium.
- Heart dilated, containing red-black blood, not completely
coagulated, and with friable myocardium. On both the
epicardium and endocardium, dark ecchymoses.
- Lungs: Normal.
(J142.19.w1)
|
Disease has been reported in either the wild or in captivity
in: |
In waterfowl:
- Ducks (B16.19.w1, B32.14.w21).
In elephants:
- Bacillus anthracis
was isolated from an adult elephant that
died at the Mipur Zoological Gardens, Dhaka. (J3.114.w8)
- Anthrax was diagnosed in an elephant (species not specified) in
Sofia, Bulgaria in 1932. (J64.21.w21)
Elephas maximus
- Asian Elephant
- In 1913, the anthrax bacillus was found in the blood smears of dead
and symptomatic elephants in an outbreak of the disease in Burma. (J3.26.w1)
- In 1927, two female elephants (of a total of seven elephants) died
of anthrax in the Zoological Society of London's Gardens (London Zoo).
(J46.1927.w1,
J64.21.w21, J388.1927.w1)
- In 1928, an outbreak of anthrax in elephants was preceded by a large
number of deaths of domestic cattle and other ruminants in India. (J12.4.w1)
- In 1949, 150 elephants were reported to have died from the disease
in Assam. (P502.1.w1)
- Recently [1992 data], a case of elephant anthrax was reported in
Kerala. Bacillus anthracis
was isolated from the heart blood in an adult working
elephant cow. (P64.1.w3,
P502.1.w5)
Loxodonta africana
- African Elephant
- Bacillus anthracis was isolated from a 15-year-old elephant
that died at the Wildlife Park, Jos, Nigeria. (J3.133.w3)
- In 1964, anthrax occurred in Chester Zoo, UK. (J64.21.w21)
- Anthrax occurs in African elephants in the wild. (J64.21.w21)
- Twenty elephants were suspected to have died of anthrax in an
outbreak of the disease that affected several wildlife species in the
Luangwa Valley, Zambia. Blood specimens were collected from four
elephant carcasses and cultured, of which two were positive. (J3.128.w5)
- In a epidemiological study of anthrax in South Luangwa National
Park, Zambia, the anthrax bacillus was isolated in four dead elephants
from a total of 85 confirmed cases of anthrax in several wildlife species. (J3.132.w6)
- A epidemiological study of anthrax mortality in ten wildlife species
in Etosha National Park, Namibia, for the period 1967-1974 detected 25
cases in Loxodonta africana
- African Elephant (
1.6% of the total detected of 1,526 anthrax cases). It was noted that
total anthrax mortality probably was higher than detected mortality,
due to carcasses not being found, or found too late for diagnosis,
etc. (B213.w4)
- A surveillance study of anthrax mortality in 19 wildlife species in
Etosha National Park, Namibia, for the period 1975-1990 revealed that
27.4% of confirmed anthrax cases and 24.4% of suspected anthrax cases
occurred
in Loxodonta africana
- African Elephant. (J64.12.w2)
In bears:
In lagomorphs:
- Wild hares in Europe (Lepus spp.) have been confirmed as
susceptible to this disease. (B209.23.w23)
Further information on Host species
has only been incorporated for species groups for which a full
Wildpro "Health and Management" module has been completed (i.e.
for which a comprehensive literature review has been undertaken). Host
species with further information available are listed below:
|
Host Species List |
MAMMALS:
(List does not contain all other species groups affected by this
disease)
|
General Information on Investigation / Diagnosis |
- Clinical signs and post mortem findings (if the carcass
has been opened by mistake). (B101,
B336.67.w67, J64.21.w21)
- Note: the carcass should NOT be opened if anthrax is
suspected; see below - Environmental and Population Control
Measures.
- Diagnosis may be difficult, particularly with an isolated case,
due to the variety of clinical manifestations. Suspicion is more
likely if there have recently been other anthrax deaths in the
same area. (B212.36)
- Blood smears, taken before or just after death. (B212.36)
- Make blood smears from the extremities (ear tips, tail, below
the hoof coronet) or smears from oedematous swellings around
localised lesions or their regional lymph nodes. (J64.21.w21)
- Bacillus anthracis is readily detected in blood and tissue
smears stained by the McFadyean (polychrome methylene blue) method or by
Giemsa staining to demonstrate the capsules. The presence of bacilli
with the typically-staining capsules is considered pathognomonic for anthrax.
N.B. the absence
of detected bacilli with capsules does not necessarily exclude the possibility of anthrax. (B88,
B101, B336.67.w67,
J64.21.w21)
- In different host species it is typical to find many bacilli in
some species but often only few in others. (J64.21.w21)
- Numbers are typically low in blood from live animals, those
which have been treated with antibiotics, and those which possess
some immunity. (J64.21.w21)
- After the animal dies, the capsules of the bacilli start to
disintegrate and the protoplasm degenerates, with less stain being
taken up; by 24 hours only "ghost cell" may be detected.
(J64.21.w21)
- In two elephants in London Zoo in 1926, anthrax bacilli were
found on a smear from a sore on one of the elephants, and in
stained tissue sections from both elephants. (J46.1927.w1)
- Bacillus anthracis isolation and identification for
uncontaminated fresh specimens are not particularly difficult. In
specimens from decomposed carcasses, detection is complicated and it is
necessary to use selective isolation techniques. (B88,
J64.21.w21)
- The organism may be cultured on artificial media, preferably
containing horse blood or serum. (J64.21.w21)
- The culture medium must not contain blood or serum from animals
which have been immunised against anthrax. (J64.21.w21)
- Selective isolation techniques may be required when specimens
have been taken from decomposed carcasses, processed products pf
animals which have died of anthrax, or from the environment, since
the presence of other flora may complicate the isolation. (J64.21.w21)
- PCR and
ELISA diagnostic tests are currently found only in specialist
laboratories. (B336.67.w67)
- In the past, the isolation and identification of Bacillus anthracis
was performed in animals. This is now generally unnecessary and should be
used strictly as the last resort. (J64.21.w21)
|
| ELEPHANTS |
- Clinical signs and post mortem findings. (B64.27.w4,
J3.114.w8,
J3.133.w3, J388.1927.w1)
- Note: the carcass should NOT be opened if anthrax is
suspected; see below - Environmental and Population Control
Measures.
- Bacillus anthracis detection in blood and tissue
smears stained by the McFadyean (polychrome methylene blue) method or by
Giemsa staining. (B64.27.w4,
J3.26.w1, J3.114.w8, J3.133.w3, J12.4.w1)
- Bacillus anthracis isolation and identification. (J3.114.w8,
J3.133.w3)
- Isolation and identification of Bacillus anthracis
in experimental animals. (J3.114.w8,
J3.133.w3)
- Note: isolation and identification of Bacillus anthracis
in animals is now generally unnecessary and should be
used strictly as the last resort. (J64.21.w21)
- In elephants at London Zoo in 1927, bacilli were numerous in the
branches of the hepatic artery but few were found in the portal veins;
it was considered that infection was probably via the skin or lungs,
not from ingestion. (J388.1927.w1)
|
| WATERFOWL |
-
Anthrax bacilli, rod shaped, in blood smears stained with methylene blue. (B14,
B16.19.w1)
|
| BEARS |
- In a Ursus maritimus - Polar bear,
diagnosed on the basis of clinical signs of localised infection (submandibullary
swelling) during an outbreak. (J3.92.w3)
- In a bear in Tsiblis, Georgia, neither the clinical signs nor the
pathological findings at necropsy were diagnostic, but Bacillus
anthracis were found on blood smears taken from the parenchymatous
organs and confirmed by culture. (J3.92.w3)
|
| Related Techniques |
|
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