Fróðskaparrit - 31.12.2000, Blaðsíða 175

SNIKAR A SEYðl I FØROYUM
179
tained material was examined under a
stereonricroscope and any nematodes pre-
sent were collected and grouped, and their
total number calculated.
Colon, coecum and rectum
The large intestine was opened and the con-
tent washed out and poured through a sieve
(mesh size of 212 pm). An aliquot of 50%
of the content was searched for nematodes,
and their total number calculated.
Lungs
The lungs were examined macroscopically
to confirm the possible presence of lung-
worms and nodular lesions associated with
nematode infection. Samples from the
nodules were examined microscopically,
and the nematode larvae present were iden-
tified.
Liver
The liver was cut into two-cm slices, and
soaked in lukewarm physiological saline
solution for 12 hours. Then the water was
poured through a sieve (mesh diameter of
106 pm), to collect any flukes present. Dif-
ferent mesh sizes were used as described
above to be sure to retain all possible para-
sites in the respective organ, but which al-
lowed other material to pass through the
sieve.
Abdominal cavitv
The abdominal cavity was searched for Cy-
sticercus tenuicollis (Taenia hydatigená).
Faeces. The faecal samples were examined
by the McMaster flotation method (Hansen
and Perry, 1994) to determine the number
of nematode eggs per gram of faeces (epg)
or protozoal oocysts per gram of faeces
(opg). Two grams of faeces were collected
from the rectum. Twenty-eight ml of flota-
tion fluid (saturated water/NaCl with glu-
cose 50 g per 100 ml) were added to make
approximately 30 ml in total. It was mixed
thoroughly. The McMaster counting cham-
ber was filled with the mixed sample (0.15
ml). After five minutes, the sample was ex-
amined under a microscope at 100 times
magnification, and nematode eggs and
Eimeria oocysts were counted. By multi-
plication of the number of eggs 'or oocysts
counted in both counting chambers by 50,
the estimated total number in 1 g of faeces
was found.
A modified Baerman analysis (Hansen
and Perry, 1994) was used to isolate larvae
from the faeces. Ten grams of faeces were
placed on two layers of gauze. The faeces,
packed in the gauze, were then dipped into
a conical beaker filled with lukewarm water
and were left to sediment for approximate-
ly 12 hours. The faeces were discarded and
the supernatant was sucked off, leaving the
sediment in the bottom. The beaker was
filled with water again, it was left to sedi-
ment for 15 minutes and the sediment was
placed on a microscope slide for examina-
tion. The degree of infection was estimat-
ed as low, medium and high. Muellerius
capillaris: low (less than 10 larvae per g
faeces), medium (10-1,000) and high
(1,000 and more). Dictyocaulus filaria:
low (less than 5 larvae per g faeces), medi-
um (5-50) and high (50-500).
The fluke egg sedimentation method was