Dr. Keve Gergo Flashcards
Copulatory bursa (bursa copulatrix) of Strongylus edentatus. Bursa copulatrix is a MALE sexual
organ, just as spiculum
Bursa copulatrix is an important morphological key to identify species. If you see bursa
copulatrix on a MALE nematode, you can think of:
Strongylids, Trichostrongylids, Oesophagostomum species, Amidostomum anseris,
Hookworms, Protostrongylids, Dictyocaulus species, Metastrongylus species and lungworms
of carnivores (but NOT Capillaria species)
(Syngamus trachea: The male is in a constant copulation with the female, therefore the
bursa copulatrix can not be seen normally)
Anterior end of Strongylus edentatus. Note the large buccal capsule, and the leaf crown (leaf like
structures around the mouth). another important morphological feature is that the bottom of the
buccal capsule is free of teeth.
Strongylus vulgaris: 2 teeth at the
bottom of the buccal capsule
Strongylus equinus: 4 teeth at the
bottom of the buccal capsule
3rd stage small strongyle larva. It is significant that the number of intestinal cells is rarely more than
8.
On this basis, it can be separated from the 3rd stage larvae of Strongylus species. Also note the the
crinkled cuticle and the long pointed tail.
Ex: cyathostomum
Strongylus vulgaris larva, with 32 intestinal cells.
Buccal capsule of an adultsmall strongyle (e.g. Cyathostomum, Triodontophorus, Cylicocyclus)species.
The buccal capsule is narrow (note the difference from adult Strongylus species) and a leaf crown is
present.
Cross-section of an Oesophagostomum larva in the colon wall. By cross-sections, it is impossible to
differentiate larvas (and most of the adults as well). Therefore, it is necessary to know each parasite’s
predilection site.
Autopsy findings in case of Oesophagostomum infection
Syngamus trachea male and female. These adults are in constant copulation, therefore the female
(larger) and the male (smaller) are always to be found together in the trachea of birds.
Pseudodiverticulum and the male Syngamus’ head. The male serves as an anchor for the female,
therefore a -so called- pseudodiverticulum forms around the male’s head in the wall of the trachea
Syngamus trachea
from inflammated lung tissue. Most of the nematodes are unrecognizeable by
their cross-sections, and many other nematodes are wandering in the lung tissue. It is important to
note however, that in this case there are nuclei in the red blood cells (see a haemorrhage).
Therefore, it is not a mammalian’s (but in this case a bird’s) lung tissue.
Buccal capsule of Ancylostoma caninum the anterior end of the worm is bent dorsally (thus the
name: hookworm) 2 times 3 teeth are visible on the edge of the mouth (lateral view)
Ancylostoma caninum (frontal view)
Uncinaria species from canids and felids
In case of these hookworms no teeth, but a pair of plates are visible on the edge of
the mouth.
Bunostomum species from ruminants
In case of these hookworms no teeth, but a pair of plates are visible on the edge of
the mouth.
Anterior end of Haemonchus contortus.
Vulva of the female Haemonchus contortus. Note the large-sized vulvar flap.
Anterior end of the adult Amidostomum anseris. Note the small buccal capsule, and the large teeth
on the bottom of it.
Amidostomum anseris
Amidostomum anseris cross-sections (gizzard of a goose)
Anterior end of a Dictyocaulus species. Note the absent buccal capsule (similar to the
Trichostrongylids)
Posterior end of a male Dictyocaulus. Note the short (throwing net-like) bursa copulatrix, and the
thick spiculum.
Male protostrongylid from the lung of a small ruminant. Try to zoom on the spiculum.
protostrongylus pulmonalis
Note the very characteristic comb-like spiculum.
Histopathological section of a nodule formed by protostrongylids. Note the large amount of worm
(and egg) cross-sections close to each other.
Anterior end of a Metastrongylus species. Note the absence of the buccal capsule. There are lips
(labia) visible around the mouth.
Posterior end of a Metastrongylus male. The spiculum is very long (1<, but <5, milimeter, depending
ont he species) and narrow. There is one (or in some species 2) hook at the end of them.
Head of Crenosoma vulpis. Note the cuticular rings (crenulated, thus the name: Crenosoma) around
the anterior end of the worm.
Tail of Crenosoma vulpis. Even though, cuticular rings can be seen on many other worms we
mentioned during the practicals (e.g. Onchocerca), Crenosoma vulpis males have copulatory bursa,
and the others do not.
Crenosoma vulpis cross-sections inside of a broncus. As previously mentioned, the cross-section of a
worm is not enough for identification, but the predilection site can be a great help. Inside of the
lumen of a bronhus, these adult worms can be found (not considering aberrant cases, e.g. migrating
Dirofilaria species):
Ruminants: Dictyocaulus species (and rarely lone adults of Protostrongylids)
Horses: Dictyocaulus arnfieldi
Pigs: Metastrongylus species
Dogs: Crenosoma vulpis
Birds: Syngamus trachea young adults (directly before moving to the trachea)
Anterior end of a roundworm. Note the three lips (labia) around the mouth.
Posterior ends of a male (left) roundworms. Note the thick cuticule, and the
absence of bursa copulatrix in case of the male. In case of the female, the vulva is very close to the
end of the tail.
Posterior ends of a female (right) roundworms. Note the thick cuticule, and the
absence of bursa copulatrix in case of the male. In case of the female, the vulva is very close to the
end of the tail.
Anterior end of a Toxocara canis. Note the cervical alae (cuticular wings)
Posterior end of Heterakis dispar. Note the prae cloacal (prae-anal) sucker (1), the different sized
spiculum (2) (thus the name: Heterakis - > Heter=different, akis=spikes), the papillas (3) and the
cuticular wings on the posterior end (4). In case of the very similar Ascaridia worms, the spiculum are
approximately of the same size)
Posterior end of Heterakis dispar. Note the prae cloacal (prae-anal) sucker (1), the different sized
spiculum (2) (thus the name: Heterakis - > Heter=different, akis=spikes), the papillas (3) and the
cuticular wings on the posterior end (4). In case of the very similar Ascaridia worms, the spiculum are
approximately of the same size)
Adult male of an Oxyuridae family member (Passalurus ambiguus). The Oxyuridae family members
have only 1 spiculum and note the ponty dagger-like tail. The large bulbus (at the base of the
rhabditiform oesophagus) is also noticeable.
Dirofilaria larvae in clotted blood
Dirofilaria (likely repens,because the cephalic space is visibly small, but immitis can be accepted as
well) microfilaria in blood smear.
Dirofilaria microfilaria in haemolized blood (Knott test)
Dirofilaria microfilaria in haemolized blood (Knott test) stained with giemsa
Strongyle-type egg: (~70-100 µm) This egg is very uncharacteristic, therefore it is not expected to
differentiate the species from each other just by the egg. (Even though it is possible).
Nematodirus egg (~200 µm). From small ruminants. An easily recognizable egg, due to its sheer size
and form. Oval, but with more acute ends. Very transparent. The developing embryo is clearly visible.
Syngamus trachea egg (~80-90 µm). From birds. Oval form, with opercular plugs on both ends. The
wall is thick, but the egg itself is transparent. The developing embryo is clearly visible
Metastrongylus egg (50-55 µm). From pigs (mainly wild boars). The egg is small, oval, but with a thick
wall and a very rough surface. There is always a larva inside.
Capillaria egg (60-71 µm). From varoius animals (in the midterm material, it is only carnivores). The
egg is tipically lemon-shaped, with two opercular plugs. The egg is not transparent, but has a dark,
reticular pattern.
Capillaria egg (60-71 µm). From varoius animals (in the midterm material, it is only carnivores). The
egg is tipically lemon-shaped, with two opercular plugs. The egg is not transparent, but has a dark,
reticular pattern.
Ascaris suum egg (~70 µm) from pigs. The egg is oval and has a (usually) brown outer shell that is
very thick and has an incredibly rough surface. The outer shell may wear off, in that case, the egg
becomes transparent. In the fresh sample, there is only a zygote inside, but after a month the L3 will
develop.
Parascaris equorum egg (~70-100 µm) from horses. The egg is round and has a (usually) brown outer
shell that is very thick and has a rough surface. The outer shell may wear off, in that case, the egg
becomes transparent. In the fresh sample, there is only a zygote inside, but after a while the L3 will
develop.
Toxocara egg (70-80 µm), from cattle (T. vitulorum), from dogs (T. canis and T. cati), and from cats (T.
cati) The egg has a round shape, with a very thick, rough, and pitted wall. These holes are giving a
reticular pattern to the wall. There is usually an embryo inside (when the sample is fresh) but the L3
larva will develop in the egg.
Toxascaris leonina egg (~80 µm) from felids and canids. The egg has a roundish/oval shape. Similar
to the Toxocara eggs, but in case of Toxascaris the surface of the wall is smooth, and and the
innermost layer has a fibrous structure
Ascaridia galli egg. (~90 µm). From birds. Oval shape, with more or less parallel walls. The egg has a
very thick and smooth wall. Most of the cases this egg is indistinguishable from Heterakis gallinarum
eggs. The average size of the latter is smaller (~ 70 µm) and they have a slightly thinner wall.
Oxyuris equi egg(s) (~90 µm). From horses. The egg has an oval shape, with an operculum on the
end. The egg is transparent, and usually we can see a larva inside.
Spirocerca lupi egg (30-40 µm). From dogs (rarely cats). The egg is very small, and transparent. The
ends of the egg are rounded, its walls are parallel to each other. Because of these facts, it is similar to
a capsule. Theres a small larva inside.
