U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
328
(a) Pathological, Histochemical and Immunohistochemical Studies of
Lungs and Livers of Cattle and Sheep Infected with Hydatid Disease
(b) Sara Elgaili Ali Ibrahim1*
and Ahmed A. Gameel2
(c) 1 Faculty of Veterinary Medicine, University of Bahri, Sudan
(d) 2 Faculty of Veterinary Medicine, University of Khartoum, Shambat, Sudan
(e)
(f) ABSTRACT
(g)
(h) This work was carried out to study the pathological changes in the lungs and livers
with hydatid disease of slaughtered cattle and sheep. Lungs and livers of 521 cattle
and 675 sheep were examined. Infection rates of 4.8% and 1.8% were recorded in
cattle and sheep, respectively. The predilection sites in cattle were the lungs and the
livers, while in sheep cysts were only found in the livers. In cattle, lung and liver,
cysts were mostly of medium size (2–4 cm), but large cysts (> 4 cm) were, also,
observed, while most of sheep liver cysts were small in size (< 2 cm). The amount of
fluid from hydatid cyst of cattle ranged from 0.2 to 50 ml; only one cyst contained
600 ml. In sheep, the cyst contained small amounts of liquid with a maximum of 3
ml. The fertility rates of the cysts were 23.4% and 11.1% in cattle and sheep,
respectively. Cyst sections from infected lungs of cattle showed laminated
membranes surrounded by a zone of cellular infiltration of mainly lymphocytes,
plasma cells, macrophages and rarely neutrophils, eosinophils and giant cells and the
outermost fibrous tissue reaction. Calcification was, also, observed. The
neighbouring tissues showed atelectasis, emphysema, haemorrhage, congestion and
fibrosis. Sections from the second, third and fourth centimeters away from the cyst
walls showed similar but less pronounced pathological reactions. In liver cyst
sections, the pathological changes were almost similar to that observed in the lungs
with atrophy and necrosis of hepatocytes. Immunohistochemical studies revealed
that all slides stained with markers for CD³ and CD²º showed positive reaction for
CD³ and negative for CD²º. This finding suggests that the cellular reaction in the
hydatid cyst wall consists mainly of T-lymphocytes. In all liver and lung sections
from cattle and sheep stained with Masson’s trichrome stain, and fibrous tissues in
the hydatid cyst capsules or around blood vessels and air passages stained green.
The acellular laminated membranes and the protoscolices, also, stained green. In
hydatid cyst sections from cattle and sheep stained with Periodic Acid Scheff (PAS),
and laminated membranes, germinal layers and protoscolices took positive PAS
magenta colour. It is concluded that the presence of cyst in an infected organ causes
pathological changes in tissues around the cyst and further away from the cyst. It is,
also, concluded that T-lymphocytes (CD³ positive cells) appear to dominate the
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
329
mononuclear infiltrate as demonstrated by immunohistochemistry. This indicates
that T. lymphocytes play a role in immunological reaction against hydatid cyst.
(i) Key words: Hydatid disease; cattle; sheep; pathology; immunohistochemistry
(j) *Corresponding author: E-mail: [email protected]
(k) INTRODUCTION
(l) Hydatid disease is a worldwide zoonosis produced by the larval stage of the
Echinococcus tapeworm. The two main types of hydatid disease are caused by E.
granulosus and E. multilocularis (Pedrosa et al., 2000). The life cycle of E.
granulosus involves two hosts. The definitive host is usually a dog but may be some
other carnivores. The adult worm of the parasite lives in the proximal small bowel of
the definitive host, attached by hooklets to the mucosa. Eggs are released into the
host's intestine and excreted in the feces. Sheep are the most common intermediate
hosts. They ingest the ovum while grazing on contaminated ground. The ovum loses
its protective chitinous layer as it is digested in the duodenum. The released
hexacanth embryo, or oncosphere, passes through the intestinal wall into the portal
circulation and develops into a cyst within the liver. When the definitive host eats
the viscera of the intermediate host, the cycle is completed (Pumarola et a.l, 1990;
Lewall, 1998). Humans may become intermediate hosts through contact with a
definitive host (usually a domesticated dog) or ingestion of contaminated water or
vegetables. Many studies have been conducted on the epidemiology, pathology and
molecular aspects of the disease (Saad, 1984; Tola, 1987; Elsawi, 1994, Adam,
1997, 2004; Osman, 2007; Omer et al., 2010). However, updating information in
animals was undertaken to provide further information on the epidemiology,
pathology and immunohistochemistry of the disease in cattle and sheep in Sudan.
(m)MATERIALS AND METHODS
(n) Samples A total of 521 cattle and 675 sheep slaughtered in Alsabaloga and Alsalam
Abattoir during the period from October 2011 to February 2012 were examined for
the presence of hydatid cysts. All organs, especially lungs and liver, were carefully
examined, and organs with cysts were described in terms of number of cysts, their
sizes and sites, contents and fertility.
(o) Pathological examination Livers and lungs from cattle and sheep were carefully
examined for the presence of any cyst. Gross description of the cyst was based on
location, size and number of cysts per organ.
(p) Histopathological and histochemical examination part of the cyst wall together
with the neighbouring liver and lung tissue up to 5 cm away from cyst wall were
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
330
taken and fixed in 10% neutral formal saline for histopathological, histochemical
and immunohistochemical studies. Tissue samples were prepared in paraffin and
sections 4-6 µm thick were prepared. Sections for routine histopathology were
stained using haematoxylin &eosin (H&E), and for histochemical study were stained
using Periodic Acid Schiff stain (PAS) and Masson's trichrome stain (Drury and
Wallington, 1980).
(q)
(r) Immunohistochemical methods
(s) Three µm sections were cut and placed on clean immunohistochemical (IHC)
microscope slides (K8020, Flex, Dako, Denmark), prepared and stained using
markers for CD3 and CD20 according to the manufacturer procedures (Dako,
Denmark).
(t) RESULTS
(u) Infective rate
(v) Infective rates of 4.8% and 1.8% were recorded in cattle and sheep, respectively
(Table 1).
(w)
(x) Predilection site
(y) In cattle, the predilection sites were the lungs followed by livers, while in sheep
cysts were only found in livers (Table 1).
(z)
(aa) Cyst size
(bb) In cattle lungs and liver cysts were of mostly medium in size (2 – 4 cm), but
large cysts were, also, observed (> 4 cm) while most of sheep liver cysts were of
small size of < 2 cm (Table 2).
(cc)
(dd) Fluid amount
(ee) The amount of fluid from hydatid cysts of cattle ranged from 0.2- 50 ml
according to the size; only one cyst contained 600 ml. In sheep, cysts contained
small amounts of liquid, maximum of 3 ml.
(ff)
(gg) Fertility of cyst
(hh) The fertility test revealed 23.4% and 11.1% fertility rate in cattle and sheep,
respectively.
(ii)
(jj) Pathological findings
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
331
(kk) Gross description: most cysts were round in shape and of variable sizes.
They were either protruding from the surface or found deep in lung or liver
parenchyma (Figs. 1 and 2). The cyst had thick membrane, the cut surface of the cyst
manifested cavities lined by a smooth membrane which could easily be removed.
Some cysts were filled with a clear or turbid fluid, caseated (cheese like) material,
and others were calcified.
(ll)
(mm)
(nn) (a)
(oo)
(pp)
(qq) (b)
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
332
(rr) Fig (1) a) Sheep liver showing multiple partially embedded cysts with thick
membrane. b) cross section of hydatid cyst in bovine liver.
(ss)
(tt) (a)
(uu)
(vv) (b)
(ww) Fig (2) a) Cattle lung showing completely embedded single cyst. b) Cattle
liver showing multiple cyst, partially or completely embedded in the parenchyma.
(xx)
(yy) Microscopic findings
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
333
(zz) In cattle lungs, sections of the first centimeter comprising the hydatid cyst
wall showed intact or disrupted laminated membrane moderate to broad fibrous
capsule. Some sections showed protoscolices, congestion, haemorrhage, fibrosis,
and heavy cellular infiltration composed of mononuclear cells mainly lymphocytes.
Hyperplasia of the bronchial and bronchiolar epithelium, atelectasis and emphysema
were seen in distant lung tissues. Fibrosis around bronchioles and blood vessels was
seen extending into the tissue parenchyma. Some sections showed calcification of
cyst wall, while others showed collapsed bronchioles. Cellular infiltration was
mainly seen in the fibrous capsule, and around blood vessels and bronchioles.
Sections of the second centimeter neighbouring the cyst, showed similar changes to
that of the first centimeter but emphysema was more pronounced. Few sections
showed slight fibrosis around bronchioles and few others showed interstitial
thickening, with presence of cellular infiltration in alveoli and airways. No
calcification was seen. Sections of the third centimeter away from cyst wall showed
congestion, haemorrhage with slight fibrosis mainly around bronchioles. Some
sections showed thickened interstitium with inflammatory cell infiltration. Sections
prepared from the fourth centimeter away from cyst wall, showed congestion,
haemorrhage, emphysema, atelectasis and cellular infiltration especially around
bronchioles.
(aaa) In sheep, liver sections prepared from the first centimeter neighbouring the
cyst wall showed congestion, haemorrhage, hepatocyte necrosis and atrophy
together with fibrosis and cellular infiltration of mainly lymphocytes and plasma
cells seen mostly in the inner side of the fibrous capsule which appeared broad.
Calcification was seen in the cyst wall. There was dilatation of sinusoids, and some
central veins. Fibrosis was, also, seen in the portal area. In the second centimeter,
most of the sections showed congestion, haemorrhage and hepatocyte necrosis.
Some sections showed fibrosis mainly in the portal areas, cellular infiltrate was seen
in sinusoids. No calcification was observed. In the third centimeter, most sections
showed similar changes to that in the second sections but the changes were less
pronounced.
(bbb) Generally, in all liver and lung sections from cattle and sheep, fibrous tissue
in the hydatid cyst capsules or around blood vessels and air passages stained green
with Masson’s trichrome. The acellular laminated membranes and the protoscolices
also took the green color. On the other hand, in the sections from cattle and sheep
stained with PAS, the laminated membranes, germinal layers and protoscolices took
positive PAS magenta colour (Figs. 3 to 6).
(ccc)
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
334
(ddd)
(eee) Figure (3) Cattle lung hydatid cyst showing continuous laminated membrane
(LM), fibrous tissue capsule(FC) and collapsed adjacent tissue (H&E X4).
(fff)
(ggg)
(hhh)
LM
FC
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
335
(iii)
(jjj)Figure (4) a) Sheep liver with hydatid cyst: showed portal fibrosis (star) (Masson’s
trichrome x10). b) cattle lung: showing fibrosis(star) (H&E x 10)
(kkk)
(lll)
(mmm)
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
336
(nnn)
(ooo) Fig(5) cattle lung tissue showing intact laminated membrane (arrow) X4, (a)
PAS stain, (b) Masson’s trichrome stain X4.
(ppp)
(qqq)
a b
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
337
(rrr)
(sss) Figure (6) Sheep liver showing broad fibrous capsule(FC), infiltration of
inflammatory cells (arrow), hepatocyte atrophy, degeneration and necrosis
(arrow)(x10).
(ttt)
(uuu) Immunohistochemical findings
(vvv) Slides stained with markers for CD3 and CD20 showed positive reaction for
CD3 and negative reaction for CD20. Positivity of CD3 varied according to the
animal species. High positivity was seen in cattle followed by sheep. The reaction
was observed mainly in cells in the cyst wall and cells infiltrating tissues
neighbouring the cyst wall. The reactions appeared as scattered brown stained cells
in the cyst wall and parenchyma in sections obtained from the two animal species.
(www)
(xxx)
FC
CC
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum, Sudan,
Conference Proceedings – Volume Two
338
(yyy) Figure (7) Cattle lung, hydatid cyst showing positive reaction for CD3
marker (x10)
(zzz)
(aaaa) (b)
Figure(8) Sheep liver showing (a) positive reaction for CD3 marker (x4). (b) Closer
view(x10).
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum,
Sudan, Conference Proceedings – Volume Two
339
Table.1 Occurrence of hydatid cysts in slaughtered cattle and sheep
Table 2. Sizes of hydatid cysts from livers and lungs of cattle and sheep
Total
No. of
cysts
Lung Total
No. of
cysts
Liver
Small
< 2 cm
Medium
2-4 cm
Large Small Medium Large
27 2 21 4 19 4 12 3
DISCUSSION
In the present study, 521 cattle and 675 sheep were examined at meat inspection
for presence of hydatid cysts. Twenty five (4.8%) and 12 (1.8%) of the cattle and sheep,
respectively, were found infected with hydatid disease. This result agrees with the results
reported by Saad (1985), Njoroge et al. (2005), Osman (2007) and Mohammed (2010)
and is comparable with those reported by Tola (1987) found high infection rate in camels
(61.3%) followed by sheep (2.1%) and cattle (2.0%) and Abdul Latif (2009) who found
infection rate of 5.18% and 7.52% in cattle and sheep, respectively. Ould Ahmed Salem
et al. (2011), also, found that the infection rates were 5.5% and 6.5% in cattle and sheep,
respectively. The present findings, disagree with those of Torgerson et al. (2009) who
reported high infection rate in sheep (64%), Azlaf and Dakkak (2006) who reported
infection rate of 56% and 40% in cattle and sheep, respectively; and with those of Fromsa
and Jobre (2011) who reported 35.15% and 11.78% in cattle and sheep, respectively.
The frequency of cysts was about equal in livers and lungs of the surveyed cattle.
In sheep, cysts were only found in the livers and were small and infertile except two
Total No. (%) Organ affected No. of
animals
infected (%)
No. of
animals
slaughtered
Animal
species Liver No.
(%)
Lung No.
(%)
47(9.0) 19(40.4) 28(59.6) 25(4.8) 521 Cattle
18(2.7) 18(100) - 12(1.8) 675 Sheep
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum,
Sudan, Conference Proceedings – Volume Two
340
cysts. These findings partially agree with Tola (1987) and Abdul latif (2009) who found
that most cysts in cattle and sheep were in the lungs followed by livers. Acosta-Jamett et
al. (2010) showed that cattle had higher prevalence in livers compared to lungs in sheep
high prevalence was in livers. Elsawi (1994), also, reported that the liver is the
predilection site in sheep infected with hydatid cyst and this agrees with Osman (2007)
and Mohamadin and Abdelgadir (2011). No cysts were observed in this study in organs
other than the livers and lungs. Mohammed (2010), also, found that hydatid cysts
measured between 0.5- 10 cm in cattle and 0.9- 3 cm in sheep. Osman (2007) noticed that
most cyst size lie between 2-6 cm in cattle and less than 2 cm in sheep. Saad (1985)
found cysts measuring up to 9.5 cm in cattle while Tola (1987) encountered cysts with an
average size of 5 cm in cattle and sheep. Tola (1987) observed that fertile cysts were
most common in sheep (60.4%) while cysts from cattle were frequently calcified
(36.4%). The present results indicated the opposite; 23.4% cattle cysts were fertile with
brood capsule and protoscolices while only 2 cysts of sheep were fertile. Saad (1985)
found that fertility rate in cattle were 29%, while Mohammed (2010) found that 23.1%
and 8.3% of cysts from cattle and sheep, respectively were fertile. However, Osman
(2007) concluded that cattle hydtid cysts were more fertile than those of sheep.
Comparing E. granulosus infection in wallapies and sheep, Barnes et al. (2007) observed
that the development of hydatid cysts was more rapid and the onset of fertility occurred
earlier in wallapies than in sheep, and that degenerative changes were more frequent in
sheep cysts. This may partially explains why sheep cysts were small and less fertile than
cattle cysts investigated in the current study. The presence of cysts in the lungs and livers
is likely to be associated with tissue damage and functional disorders, and this has been
indicated by the histological changes observed in infected organs. In the current study,
the number of cysts encountered in the infected lungs and livers in the two animals
examined ranged between 1 to 3 cysts except one cattle liver which contained 15 cysts.
This finding agrees with Tola (1987) who reported that most infected organs contained 1-
2 cysts but multiple infection with more cysts/animal were, also, observed.
The structure of cyst wall comprised the laminated membrane with a thin inner most
germinal layer surrounded by a zone of mononuclear cells of mainly lymphocytes
(occasionally with neutrophil, eosinophil and giant cells) and fibrous tissue capsule.
Marked eosinophil infiltration reported by some authors (Sakamoto and Cebrera, 2003)
has not been observed here. Laminated membrane was in most cases disrupted and the
fibroplasias was variable being more pronounced in caseated and calcified cyst and in
case of sheep cyst. Saad (1985), Verma and Swammy (2009) reported that the fibrous
capsule response was dense and diffuse in fertile cysts. However, the laminated
membrane varied in thickness and in some sections was not clearly visible. Degenerated
laminated membranes were associated with heavy infiltration of inflammatory cells in the
inner side of the fibrous capsule. These features have been previously descriped (Hamid,
2012; Barnes et al, 2011; Kul and Yeldiz, 2010; Osman, 2007; Verma and swammy,
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum,
Sudan, Conference Proceedings – Volume Two
341
2009). Pathological changes have been observed in both liver and lung tissues around the
cyst wall; atelectasis, bronchiolar collapse and emphysema were seen in lung tissue, and
hepatocyte atrophy, degeneration and sinusoidal dilatation were observed in liver tissue.
In few sections from cattle brood capsules and protoscoleses were seen histologically.
Such changes has been previously noted in lungs and livers infected with hydatid disease
(Adam, 1997; Osman, 2007). Sections from lungs and livers prepared from sites up to
five cm away from cyst wall exhibited significant changes which were less expressed
further away from the cyst wall, and there were mainly attributed to the pressure effect
exerted by the hydatid cyst.
For Histochemistry, sections of hydatid cyst were stained using periodic acid Schiff
(PAS) and masson’s trichrome stains. The cyst wall consisted of three layers which are
inner most germinal layer, laminated layer and outer fibrous layer. PAS staining was
found to be superior in showing the laminated membrane and germinal layer where as
Masson’s trichrome was equally good in showing the laminated membrane and superior
in demonstrating the fibrous tissue capsule. These findings agree with that of Khalifa et
al. (2005) who concluded that the three layers of the cyst wall were better stained with
PAS, due to the presence of mucopolysaccharides and glycoproteins in laminated layer,
and also agree with Rashed et al, (2004) who used PAS and Masson’s trichrome stains
and found that the thickness of layers varied with each stain according to glycogen and
mucopolysaccharide content. In the present investigation, immunohistochemical studies
were performed in an attempt to characterize the lymphocyte infiltrate within liver and
lung tissues. The results showed that the inflammatory cells in all sections showed
positive reaction for CD3 markers but negative reaction for CD20 markers. The negative
reaction to CD20 markers indicates absence of B - lymphocytes as CD20 represent positive
B cells. On the other hand, CD3 represent positive T- lymphocytes and CD3 surface
marker is associated with the T cell receptors in both CD4 and CD8 cells. The number of
CD3 positive T cells is an approximation of the sum of CD4 and CD8 T cells (Keir et al.,
2002; Naji et al., 2007). This indicates that the cells infiltrating the hydatid cyst wall in
the sections examined belonged to the CD4, CD8 T lymphocytes which may play a role in
the immune response of animal hydatidosis as suggested in case of human infection
(Pearce et al., 1991).
REFERENCES
Abdul Latif, A. (2009). Genotyping of Echinococcus granulosus in Punjab. PhD thesis.
University of the Punjab, Quaid-E-Azam, Lahore.
Acosta-jamett, G.,Cleaveland, S., Cunningham, A.A., deC.Bronsvoort, B. M. and Craig,
C. (2010). Echinococcus. granulosus infection in humans and livestock in the
Coquimbo region, North-central Chile. Veterinary Parasitology. 169: 102-110.
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum,
Sudan, Conference Proceedings – Volume Two
342
Adam, A. (1997). Some epidemiological indicators of the Echinococcosis/ Hydatidosis
infection in dogs, cattle, camels, and man in nyala town, Southern Darfur state,
M. T. A. H, Thesis. University of Khartoum.
Adam, A. (2004). Some epidemiological aspects of Echinococcus granulosus and isolate
characterization in animals in Darfur region, PhD, thesis. University of
Khartoum.
Amer, H. A; Nibal, A. H; Dalal, S. M; Hassan, H. M.(2007). Pathological and serological
studies on cystic echinococcosis in naturally infected camel calves. veterinary
medical journal giza. 55(1): 115-129.
Azlaf, R. and Dakkak, A. (2006). Epidemiological studies of the cystic Echinococcosis in
Morocco. Veterinary Parasitology. 137: 83-93.
Barnes, T. S., Hinds, L. A., Jenkins, D. J., Bielefeldt-Ohmann, H., Lightowlers, M. W.
and Coleman. G. T. (2011). Comparative Pathology of Pulmonary Hydatid Cysts
in Macropods and Sheep. Journal of Comparative Pathology. 144:113-122.
Drury, R. A. B. and Willington, E. A. (1980). Carleton’s histological technique. Fifth
Edition. Oxford University press. London.
Elsawi, A. S. A. (1994). Natural and experimental infection of sheep and goats with
hydatidosis. M. V. Sc, Thesis. University of Khartoum.
Fromsa, A. and Jobre, Y. (2011). Infection prevalence of hydatidosis (Echinococcus
granulosus, Batch, 1786) Asynthesis report of previous reports in domestic
animals in Ethiopia. Ethiopian Veteterinary Journal. 15(2): 11-33.
Hamid, M. H. A. (2012). Pathological studies on hepatic lesions of camel (camelus
dromedaries) slaughtered at Tambool abattoir, Sudan. M. V. M, Thesis.
University of Khartoum.
Keir, H. E., Rosenberg, M. G., Sandberg, J. K., Jordan, K. A., Wiznia, A., Nixon, D. F.,
Stoddart, C. A. and Mc Cune, J. M. (2002). Generation of CD3
CD8 low
T
lymphocytes in the HIV type 1- infected thymus. Journal for Immunology.
169(5): 2788 – 2796.
Khalifa, R. M. A., abdel-rahman, S. M., Monib, M. S. M and Yones, D. A. (2005).
Characteristics of hydatid cyst of camel strain of Echinococcus granulosus in
Assiut. Elminia Medicine Bulletine. 16(1): 202-214.
Kul, O.and Yildiz, K. (2010). Multivesicular cysts in cattle: Characterisation of unusual
hydatid cyst morphology caused by Echinococcus granulosus. Veterinary
Parasitology. 170: 162–166.
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum,
Sudan, Conference Proceedings – Volume Two
343
Lewall, D. B. (1998). Hydatid disease: biology, pathology, imaging and classification.
Clinical Radiology. 52:863-874.
Mohamadin, S. A.and Abdelgadir. A. E. (2011). Study on hydatid cyst infection in
Slaughterhouses in Khartoum state, Sudan. Archives of Applied Science
Research. 3(6):18-23.
Mohammed, N. A. A. (2010). Experimental Hydatidosis in the Sudan: transmission and
natural infection. PhD, Thesis. University of Khartoum.
Naji, A., Le Rond, S., Durrbach, A., Radonne, I. K., Creput, C., Daouya, M., Caumartin,
J., le Maoult, J., Carosella, E. D. and Roues-Freiss, N. (2007). CD3+
Cd4 low
and
CD3+
CD8 low are induced by HLA-G novel periplural blood suppressor T cell
subsets involved in transplant acceptance. Blood.10(12):3969-3948.
Njoroge, E. M., Mbithi, P. M., Gathuma, J. M. Wachira, T. M., Gathura, P. M.,
Magambo, J. K. and Zeyhle, E. (2005). A study of cystic Echinococcosis in
slaughtered animals in three selected areas of northern Turkana, Kenya.
Veterinary Parasitology. 104: 85-91.
Omer, R. A., Dinkel, A., Romig, T., Mackenstedt, U., Elnahas, A. A., Aradaib, I.E.,
Ahmed, M.E., Elmalik , K.H. and Adam , A. (2010). A molecular survey of
cystic echinococcosis in Sudan. Veterinary Parasitology. 169: 340–346.
Osman, A. M. A. (2007). Pathological and biochemical study on hydatid disease in
camels, cattle and sheep. M. V. M, thesis. University of Khartoum.
Ould Ahmed Salem, C. B., Schneegans, F., Chollet, J. Y. and et Jemli, M. H. (2011).
Epidemiological studies on Echinococcosis and characterization of human and
livestock hydatid cysts in Mauritania. Iranian Journal of Parasitology. 6(1): 49-
57.
Pearce, E. J., Caspar, P., Grzych, J. M., Lewis, F. A. and Sher, A. (1991).
Downregulation of Th1 cytokine production accompanies induction of Th2
responses by a parasitic helminth, Schistosoma mansoni. Journal of
Experimental Medicine. 173:159-166.
Pedrosa, I., Saíz, A., Arrazola, J., Ferreirós, J.and Pedrosa, C. S. (2000). Hydatid
Disease: Radiologic and Pathologic Features and Complications. Radio Graphic.
20:795-817.
Pumarola A, Rodriguez-Torres A, García-Rodriguez JA, Piédrola-Angulo G.( 1990).
Microbiología y parasitología médica 2nd ed. Barcelona, Spain: Salvat..
Rashed, A. A., Omer , H. M., Fouad, M. A and Al Shareef , A. M. (2004). The effect of
severe cystic hydatidosis on the liver of a Najdi sheep with special reference to
U. of K. Graduate College and Scientific Research. The 5th Annual Conference - Agricultural and Veterinary Research - February 2014, Khartoum,
Sudan, Conference Proceedings – Volume Two
344
the cyst histology and histochemistry. Journal of Egyptian Society of
Parasitology. 34(1):297-304.
Saad, M. B. (1985). Hydatidosis/ Echinococcosis in the Sudan with emphasis on
epidemiology, experimental transmission and histopathology. PhD, Thesis.
University of Khartoum.
Sakamoto, T. and Cabrera, P. A. (2003). Immunohistochemical observations on cellular
response in unilocular hydatid lesions and lymph nodes of cattle. Acta Tropica.
85 (2):271-279.
Tola, H. M. (1987). On the sero-epidemiology of hydatid disease. M. Sc, Thesis.
University of Khartoum.
Torgerson, P. R., Ziadinov, I., Aknazarov, D., Nurgaziev, R. and Deplazes, P. (2009).
Modelling the age variation of larval protoscolices of Echinococcus Granulosus
in sheep. International Journal for Parasitology. 39: 1031- 1035.
Verma, Y. and Swamy, M. (2009). Prevalence and pathology of hydatidosis in buffalo
liver. Buffalo Bulletin. 28(4) p. 207-211.