STUDIES ON SOME INTERNAL PARASITES OF GOATS IN ASSIUT GOVERNORATE  ESPECIALLY WHICH AFFECTING LIVER

Mohsen. I. Arafa and Ibrahem. A. Fouad

Animal Health Research Institute, Assiut Laboratory

INTRODUCTION:

Goats play an important role in providing animal protein for the diet, especially for these people who live in the villages in addition to cashmere and mohair fibers production (Smith and Sherman, 1994).

Under arid conditions especially when accompanied with unsuitable hygienic measurements goats become susceptible to various parasitic infections. The parasitic diseases are sometimes so serious causing great economic losses and their mortality rate may be reach to 30- 40% (ٍSoulsby, 1965).

The goats also serves as an intermediate host for a number of cestode parasites that used canids as definitive host as Echinococcuse granulosus, Taenia hydatigena and Taenia ovis. These infection are more economically and clinically significant than the adult tapeworm infections (Smith and Sherman, 1994).

However, little studies are available on the internal parasites of goats especially in Upper Egypt.

Therefore, the present work was planned to study the prevalence of different parasites infect goats in Assiut Governorate and the relationship between them. In addition to explore the pathological alterations in some infected livers of examined goats.

MATERIALS AND METHODS:

1-Collection and examination of fecal samples:

Three hundred and fifty rectal fecal samples were collected from apparently healthy goats (153 less than six months and 197 more than six months) from different localities in Assiut Governorate during January 2006 to December 2006. Each sample was collected in clean plastic cup and delivered directly to the laboratory for examination.

 - Fecal samples were examined for the presence ofdiagnostic parasitic stages by both the centrifugation floatation using saturated sodium chloride solution and sedimentation techniques (Abdel-Gawad 1972).

 - Fecal culture was performed for identification of stongyloride larvae according to Eckert (1960).

- Identification of the collected eggs and larvae was done according to Dunn (1978) and Soulsby (1982).

 - The percentage of infection, age and seasonal variations of each species were determined.

2-Gross and histopathological exami-nations of liver:

- A total of 350 adult goats were slaughtered in different Assiut abattoirs, their livers and corresponding bile ducts were macroscopically examined carefully for parasitic infection.

- Interesting samples of the liver tissue were divided into two parts; one half was fixed in 10% neutral buffered formalin. Fixed tissues were processed routinely for paraffin embedded technique, sectioned at 4 um and stained with hematoxylin and eosin (H&E) according to Bancroft and Stevens (1982). Other half was digested in artificial gastric juice for isolation of oocysts and larvae distributed in the liver tissues according to Bhopale and Johri (1975).

RESULTS AND DISCUSSION:

1 -Frequency of occurrence:

 Out of the 350 goat feacal samples were examined in the present survey, only 29 goats were parasitic negative, the remaining 91.7% were positive at least by one type of parasitic infection.

Eimeria infection was the most prevalent parasitic infection (88.9%) in surveyed goats; their infection rate was 96.4% in kids and 87.3% in adults. High incidence is the common phenomena of Eimeria; Norton, (1986) detected it in 98% of goats at England, Ocallaghan, (1989) at South Australia recorded it in 97%, and Alyousif et al., (1992) detected it in 90.3% at Saudi Arabia. In Egypt Otify (1984) and Arafa (2001) detected it in 94.65% and 93.25% of examined goats respectively. Smith and Sherman (1994) mentioned that Eimeria oocysts are widely present in faeces of both normal and diseased goats with reported range of 38% to 100% of all goats. They attributed the high incidence of Eimeria to the quite resistance of theiroocysts to the environmental degradation and exposure of animals to poor hygienic conditions.

 Concerning to helminthes infection in the present work, they were detected in 25.4% of examined goats, where the infection rate was 32.0% in adults and 17.0% in kids (Table 1).

Most cases of helminthes infection in the present work were mixed with Eimeria infection 22.57% (Table1). Kanyari (1993) mentioned that there is a positive correlation between Eimeria and helminthes infection in examined sheep and goats, this related to the role of contamination in the acquisition of both types of infection.

 Fourteen genera of helminthes were detected in examined goats listed in tables 2 & 3. Infection with Cooperia, Skarbojenema and Paramphestomum had not previously been reported in goats in Assiut Governorate. The incidence of most detected helminthes observed in the present work was lower in kids than adults. Infection with Fasciola, Ostertagia and Capillaria were detected in adults only.

Table (1): Prevalence of parasitic infection in examined goats in Assiut Governorate

Table (2): Prevalence of different parasites in examined goat at Assiut Governorate

Table (3): Prevalence of helminthes detected by feacal culture in examined goats

Regarding to nematode infection, they were detected in 22.0% of examined goats. The most predominant nematodes in examined faecal samples were Strongyloride- like eggs (19.1%) while in faecal culture the predominant worms wereTrichostrongylus sp. Oesophagostomum sp. and Bunostomum sp., their infection rates were 6.3%, 4.3% & 4.0% respectively (Tables 2 & 3 Plate I).

The percentages of nematode infections in the present work were lower than that mentioned by Monib (1977) who recorded the percentage of: Trichuris, Heamonchus and Oesophagostomum,as 77.6%, 14.4% and 7.2%, respectively. While the obtained results is higher when compared with that recoded by Ahmed (1998) who reported that nematode infection rate in goats at Assiut and Sohag Governorates was 9.2% and he added also that Trichostrongylus sp. was the most common nematode (2.6%). This difference mostly attributed to several factors as breeding system of examined animals, phase of infection during the examination or laboratory techniques used in examination of samples.

Concerning to trematode infection, their total infection rate was 3.7%. Fasciola eggswere detected only in adult goats and their rate was 6.1%. The obtained result agreed with Haridy et al., (1990) and Sobhy (2004) they detected Fasciola in goats at 3.54% and 3.41% respectively. Absence of Fasciola infection in kids in the present work agree with the same result of El- Sherif & Abo-El-Hadid (2005) they mentioned that fascioliasis infection began to appear at five to six months of age. Infection with Paramphestomum sp. detected in both kids and adults, their rates were 0.65% and 1.0%. Cestode infection represented as Moniezia sp. was detected in 2.9% of examined goats (Table 2). Moniezia infection was detected previously in goats by Monib (1977) while Paramphestomum infection had not detected previously.

 Regarding to the effect of seasonal variation on the incidence of parasitic infection were listed in table (4); Eimeria infection was high allover the year especially in summer season, it was ranged from 83.7% in autumn to 93.8% in summer. This result agreed with Harper and Penzhorn (1999) they found a significant increase in infection rate of Eimeria during dry season. Smith and Sherman (1994) mentioned that hot and humid weather is particularly conducive to sporocyst development and outbreaks of clinical coccidiosis are common during summer, especially spring–born kids are being weaned during the hot, humid months.

Regarding to the seasonal distribution of nematodes in the present work noticed that: incidence of most nematodes (strongyloride) increased gradually at autumn and reached to the peak of infection either in winter or spring. A pronounced decline in infection rate was usual seen in summer. This pattern of infection of strongyloride may relate to the spring rise phenomena in addition to the infective stages of most strongyloride worms not resist the hot dry weather. Soulsby (1965) and Herd (1971) mentioned that: end of winter and beginning of spring is considered as the peak of reproduction of most strongyloride worms. They added also, maturation of their inhibited larvae takes place in spring season which known as spring rise. Vice-versa, peak of infection of Trichuris ovis was detected in summer; this may related to their infective stage is more resist the hot dry season as a result of their thick shell. Infection rate of Fasciola sp. in the present work was relatively similar at each season. This may  be related to long life- span of this parasite, extensive movement of goats and irrigation by flooding. Concerning to Moniezia sp. the maximum of their infection rate was detected in autumn, which may followed the activity of their intermediate host (Oribatid mites). Hassaein (1978) mentioned that the highest activity of Oribatid mites was seen in summer season. Low level of other helminthes (Capillaria, Toxocara vitulorum and Paramphestomum) not help to study their seasonal distributions.

Table (4): Seasonal variations of different parasites in examined goats at Assiut

2-Liver examination:

 Gross post-mortem examination of 350 slaughtered goats revealed the presence of: Fasciola infections in 6.28% and Cysticercus tenuicollis in 6.86%. Histopathological examination of liver tissues revealed presence of Ascarid sp. larvae in 0.3% and Eimeria infection in 0.3% (Table 5).

A- Fasciola infection:

 Fasciola sp. that detected in present study was only F. gigantica depending upon morphological criteria of the adult flukes. The obtained result similar with the pervious studies at Assiut Governorate by: Monib (1977) and Ali (2001), they recorded that the infection rate of fascioliasis in slaughtered goats was 6.4% and 11.6% respectively.

 In the present work the incidence of Fasciola in slaughtered goats not coincided with those found in faecal examination of living once. This difference may be interpreted to the low number and irregular pattern of egg production in addition to the pathological changes in the affected liver, in addition to all slaughtered goats were more than 8 months. The same difference was detected by Abdel-Aal et al. (1999) in examined goats at Ismailia province.

B–Cysticercus tenuicollis:

 The recovered cysts were either embedded in the hepatic tissues or attached to the liver surface with long neck. They were variable in size measured 1.5-3.0x1.0-2.5 cm (2.0x1.5 cm). Most of detected cysts were transparent grayish white in colour, they had a thin wall through which a single scolex appeared as a white spot (plate II Fig. 1).

 The incidence of C. tenuicollis in the present work was relatively coinciding with that obtained by Ali (2001) in Assiut Governorate but it was lower than that recorded by Fathi and Abel Haseeb (2006) they detected it in 19% of examined goats in Libya. This difference may attribute to high populations of stray dogs and other wild carnivores in desert regions of Libya which play an important role in infection with  C. tenuicollis.

C-Eimerian infection:

 It was detected in one goat; the liver was enlarged and had multiple firm gray–white patches. These patches had tortuous shape. Cut sections in these patches revealed enlarged easily recognizable proliferated bile ducts. Microscopical examination of their content revealed presence of small spherical eimerian oocysts identified as Eimeria alijevi depending upon their measurements (16.3x13.6µm) and morphological characters (Plate II Fig. 2). It is the first time for detection of hepato-biliary coccidiosis in goats at Assiut Governorate. Several species of Eimeria (E. alijevi, E.caprina and E. ninakohlykimovae)were detected in liver of goats previously by;Dia et al. (1991) and Mahmoud et al. (1994).

Table (5): Incidence of various Parasitic infection in liver of examined goats (350 cases)

(Plate I):  Figures of some nematode eggs and larvae of examined goats

(1) Capillaria sp. egg.                                                                                                                                                              (2) Skarbojenema sp. egg.                                                      

(3&4) Strongyloride eggs.                                                                                                                                      (5) Trichuris sp. egg.                                                                                                              

(6) 3^rd stage larva of Ostertagia sp. X 40.                                                                                               (7) 3^rd stage larva of Trichostrongyus sp. X 40.                     

(8) 3^rd stage larva of Chabertia sp. X 40.                                                                                                               (9) Anterior end of 3^rd stage larva of Cooperia sp. X 100.

(10) 3^rd stage larvae of Haemonchus sp., note bullet -shaped head (arrow) X 40.

(11) Posterior end of 3^rd stage larva of Ostertagia sp. X 100.                                               

(12) Posterior end of 3^rd stage larva of Trichostrongylus sp. X100.

(13) Posterior end of 3^rd stage larva of Chabertia sp. X100.

(14) Posterior end of 3^rd stage larva of sp. Cooperia sp. X 100.

(15) Anterior end of 3^rd stage larvae of Haemonchus sp. X 100.

(Plate II)

Fig. (1): Variable size of detected Cysticercus tenuicollis in examined goats, note scolex as white spot (arrow).

Fig. (2): Coccidian oocyctes detected in content of bile ducts X 100.

Fig. (3): Periportal area showing disruption of hepatic cords caused by fibrous connective tissue proliferations. H& E X 200.

Fig. (4): Liver of a goat showing necrobiotic changes of hepatocytes. Note the presence of coccidian macrogamonts (arrow) and microgamonts (arrow heads) in hepatic sinusoids. H&E X 320.

Fig. (5): Periportal area showing hypertrophy of biliary epithelium and inflammatory cell reactions composed of macrophages, lymphocytes, eosinophils and fibrocytes. H&E X 320.

The gross features which detected in present work were similar among reported cases of hepatic coccidiosis in rabbits, mink and goats (Grafiner et al., 1967, Levine, 1985, Dubey, 1986 and Yabin et al., 1991). In contrast, in a calf with hepatic coccidiosis, liver was enlarged but bile ducts were not sufficiently enlarged to be grossly recognizable (Collins et al., 1988).

                Histopathological examination of affected liver revealed that: portal and peri-portal areas contained much fibrous connective tissue and inflammatory cell reactions composed of macrophages, lymphocytes and eosinophils (plate II Figs. 3-5). The hepatic cords were disrupted and hepatocytes especially in peri-portal areas showed necrobiotic changes (plate II Figs. 3-5). Many intrahepatic bile ducts had uneven luminal surface and were lined by tall columenar epithelium with enlarged nuclei and nucleoli, indicating hypertrophy and hyperplasia (Plate III Figs. 1&2). Different stages of coccidian included meronts, macrogamonts and microgamonts were encountered intracytoplasmic in epithelial cells of hyperplastic bile ducts (Plate III Figs 1,2 &3). Four or more merozoites were observed in each meronts (Plate III Fig. 2). Macrogamonts and microgamonts were occasionally observed free in portal areas or in hepatic sinusoids (plate III Fig. 3). Oocyts could be observed with cell debris and sloughed epithelial cells in lumen of bile ducts (plate III Fig. 1).

                These inflammatory reactions encountered nearby the parasitized bile ducts and necrobiotic changes of hepatocytes may attribute to direct or indirect action of coccidian organisms. The later opinion had been previously considered by Schafer et al. (1995) who attributed the presence of hepatic necrosis in hepatic coccidiosis of goats to one or more stages of coccidian organisms either directly or indirectly.

As a rule, a potential route of hepatic infection with coccidian is ascending infection from the intestine via bile ducts or via lymphatic (Lindsay et al., 1990 & Schafer et al., 1995). Limited researches indicated that coccidia may be transported in the circulation within macrophages (Schafer et al., 1995). In the present study, the presence of macrogamonts and microgamonts in hepatic sinusoids may indicate the haemato- genic route.

D–Ascaridlarvae:

In another goat, the liver had pale spots (0.5 cm. in diameter). These spots had normal consistency and extended shortly in hepatic parenchyma. Highly granulated rhabditiform larvae were recovered by microscopical examination of the artificial digested liver tissues, their measurements were 270-350 x16.5- 18.8 µm(plate IV Fig. 1). The morphological criteria of the detected larvae were coincided with that of second stage larvae of ascarid worms. Smyth (1994) mentioned that Ascaris larvae appear as second stage larvae in the liver within six hours post-infection and remain in the liver for a few days and then develop to the early third stage larvae. Isolation of Toxocara vitulorum larvae from liver and other internal organs of experimentally infected chickens by artificial digested juice was previously done by Sabry (2001).

Histopathological examination of the affected tissue revealed the presence of parasitic granulomas. Each of them composed of a necrotic core containing a cross section in the larva and surrounded by aggregations of lymphocytes, macrophages and eosinophils (plate IV Fig. 2). These granulomas were demarcated by fibrous capsule (plate IV Fig. 2). The hepatocytes were more or less unchanged. A part of the larva was observed in close contact with arterial intema (plate IV  Fig. 3).

(Plate III)

Fig. (1): Periportal area showing hyperplasia of a bile duct epithelium with presence of intra–cytoplasmic  coccidian meronts. The lumen of bile duct contains oocysts and cellular debris. H&E X 200.

Fig. (2): Higher magnification of the Fig. (1), showing presence of four merozoites within the coccidian meront  H&E X 800.

Fig. (3): Liver of a goat showing presence of different stages of coccidian in epithelial cells of bile ducts H&E X 200

Fig. (4): Periportal area showing hyperplasia of a bile duct epithelium, mononuclear cell reactions and presence of microgamonts (arrow). H&E X 320.

(Plate IV)

Fig. (1): Ascarid second stage larvae detected in digested liver of infected goat X 80.

Fig. (2): Liver of a goat showing presence of a parasitic granuloma composed of necrotic core containing a longitudinal section in the larva and surrounded by lymphocytes, macrophages, eosinophils and a fibrous capsule. H&E X 320.

Fig. (3): Periportal area showing presence of larva in- close contact with arterial intema H&E X 200.

Migration of nematode larvae through the internal organs especially the liver and lungs is a common occurrence in domestic animals (John et al., 2001). Infective ascarids larvae penetrate the intestinal wall and migrate to the liver via the portal circulation (John et al., 2001). Presence of the detected larvae in a portal blood vessel in a goat in the present study was agreed with the last postulation. The composition of the hepatic granulomas in the present study was similar to granulomas elicited by nematode larvae or its eggs (Ibrahim et al., 1989. Palmer et al., 1998 and John et al., 2001). Multiple parasitic granulomas detected in the present case caused by ascarid larvae indicated high response of goat’s liver as a migration route for Ascaris larvae.

                Results of the present work proved that goats play a very important role in dissemination of internal parasites between different animals. Dangerous of this role increase by the fact that the examined goats were apparently healthy.

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