PREVALENCE OF HYDATID CYSTS ISOLATED FROM DIFFERENT INTERMEDIATE HOSTS IN DUHOK ABATTOIR, KURDISTAN REGION, IRAQ

ABSTRACT

This study was an attempt to investigate epidemiological of hydatid cyst isolated from liver and lungs of infected intermediate host (sheep, goats and cattle) in Duhok abattoirs. Samples were collected during the period from September 2020 to March 2021, out of 28465 sheep, 1264 goats and 4629 cattle slaughtered were examined. It has been found that 2.90% of sheep, 3.08 % of goats and 0.17 % of cattle were infected with hydatid cysts. Among infected sheep, 30.59% of the hydatid cysts were found in the lungs, 60.33 % found in the liver and 9.06% were found in other organs. Among infected goats 33.33% were found in lungs, 64.10 % in the liver and 2.56 % of hydatid cyst were found in other organs, while among infected cattle, 25% were found in lung, 62.5 % in the liver and 12.5 % were found in other organs. According to the types of the cysts, sheep HCs showed the highest percentage (64 %) of fertility, followed by goats (50 %) and the least (29.03 %) in cattle. Regarding the sterile cysts, the highest percentage (67.74%) in cattle, followed by goats (31.25%) and sheep (22%). Regarding the sex, the infection in female was higher (28.84%) than the male (1.41%).  

АННОТАЦИЯ

В данной статье была сделана попытка изучить эпидемиологию гидатидной кисты, полученной из печени и легких инфицированного промежуточного хозяина (овец, коз и крупного рогатого скота) на скотобойнях Дахук. Для исследования были взяты образцы у 28465 овец, 1264 коз и 4629 голов крупного рогатого скота в период с сентября 2020 года по март 2021 года. Было установлено, что у 2,90% овец, 3,08 % коз и 0,17 % крупного рогатого скота были найдены гидатидные кисты. Среди инфицированных овец 30,59% гидатидных кист были обнаружены в легких, 60,33 % - в печени и 9,06% - в других органах. У инфицированных коз 33,33% гидатидных кист были обнаружены в легких, 64,10 %- в печени и 2,56 % - в других органах, в то время как 25% гидатидных кист были обнаружены в легких инфицированного крупного рогатого скота, 62,5 % в печени и 12,5 % были найдены в других органах. Самый высокий процент фертильности 64 % был установлен у овец, 50 % у коз и наименьший показатель был выявлен у крупного рогатого скота - 29,03 %. Самый высокий процент стерильных кист 67,74% был обнаружен у крупного рогатого скота, 31,25% - у коз и 22% - у овец. Заболеваемость у самок животных была выше (28,84%), чем у самцов (1,41%).

Keywords: Hydatid cyst, Cystic Echinococcosis, Protoscolices, Hydatidosis.

Ключевые слова : гидатидная киста, кистозный эхинококкоз, протосколисы, гидатидоз.

1. Introduction:  

A cystic Echinococcosis (CE) or hydatid cyst (HC) is a neglected zoonotic disease (NZD) of cosmopolitan distribution caused by the larval stage of the Echinococcus granulosus (Eckert and Deplazes, 2004). Human can be infected with the larval stage if he ingests the eggs of the parasite with either food or drinks were ingested (Thompson, 1986). The adult parasites are found in the small intestine of the definitive hosts, while the larval stages occur as a cyst in the visceral organs (mainly in the liver and lungs) of the intermediate host, causing hydatidosis (Thompson, 1995).  Hydatid cyst develop in various organs, the commonest site of infection is the liver, the lung, followed by other organs such as kidneys, spleen, heart, and the brain, may also be infected (Morar and Feldman, 2003). There are six species of Echinococcus: E. granulosus, E. multilocularis, E. vogeli, E. oligarthrus, E. shiquicus and E. felidis (Brunette, 2012), two of these species are of medical importance, which are E. granulosus and E. multilocularis causing Cystic Echinococcosis (CE) and Alveolar Echinococcosis (AE), respectively. Furthermore, Iraq including Kurdistan region is considered as an endemic country for HCs as many domestic animals including sheep, goats, camel, cattle and buffalo act as intermediate hosts, while dog and wolf act as final host (Abdullah, 2010). The present study aims at the identification of the prevalence of hydatid disease in slaughtered animals in Duhok abattoir and its correlation with the location of the cysts in various organs and gender of animal and also the types of the isolated cysts and fertility rate.

2. Materials and methods:

The epidemiological study included a total of 34358 slaughtered animals of both sexes were examined for hydatid cyst during post mortem inspection including sheep (28465), goats (1264) and cattle (4629), during the period from September 2020 to March 2021. The investigation of hydatid cysts was carried out for the following parameters: location of cysts (organ specificity), sex and the type of cyst. The samples were transported to the laboratory in a cool box. In the laboratory the Hydatid cyst fluid (HCF) in infected organ (Figure 1) aspiration by using a large size needle, the contents were placed in centrifugal tube and centrifuged for 5 minutes at 3000 rpm, then one drop of precipitated was taken by Pasteur pipette and examined by light microscope under (40x) for the presence of protoscolecies (Figure 2), the cysts which were without protoscolices were considered as non-fertile (Daryani et al., 2006).

Figure 1: Infection organ in the liver of sheep.       Figure 2: Photos of protoscolices (10X).

3. Result and Discussion

3.1. Prevalence of hydatidosis in animals at Duhok abattoir

The number of infected sheep, goats and cattle with HCs is given in Table (1). It is obvious from the results that the highest rate (3.08%) of infection was in goats followed by sheep (2.90%) and the least (0.17%) in cattle. The results of this study are disagreed with many studies reported in the Duhok province by Ghaffar (2008), Abdullah (2010) and Al-Berwari (2012) in Duhok, they found high rates of infection in sheep (15.5%, 12.3% and 19.46%) as compared with goats (1.4%, 5.2% and 15.52%), respectively. Also, it is different with study conduct in Slemani province (Mero et al., 2014) the prevalence rate of HC in sheep was highest in goats and cattle (12.7%, 4.8% and 4.3%) respectively. They attributed the high rate of infection in goats due to the host specificity and strain distribution in the region, the higher infection in goats may be due to the fact that very large number of female goats and the older ages of animal was slaughtered in the abattoir of this region and also more desirable for consumption. Very low prevalence rate of HCs among cattle (1.68%) in this study may be due to their rearing as they were mostly kept in cowshed with better care such rearing conditions decrease the chances of their contact with infection sources (Thompson and McManus, 2001).

Table 1.

Prevalence of HCs in sheep, goats and cattle slaughtered in Duhok abattoir

3.2. Organ specificity

The distribution of HC in various organs is shown in Table (2). The results which revealed that the most commonly involved organs in sheep was liver the rate of infection was 60.33 %, in the lungs the rate of infection was 30.59 % and in the other organs was 9.06 %. While in goats the highest rate of the infection (64.10 %) was in the liver, followed by in the lungs (33.33 %) while the lowest rate (2.56 %) was reported in other organs. In cattle the liver was the predominant site for hydatidosis in which the rate of infection was 62.5 %, followed by the lungs (25 %), while the least (12.5 %) was in other organs.  The result of this study is disagreed with study in Duhok (Meerkhan et al., 2018) Was found the lungs had a higher prevalence in both sheep and goats (61.65 and 58.38%, respectively), while in cattle; liver had the higher prevalence (64.84%). In another study in zakho city (Al-Bosely, 2013), the high infection in sheep were found in both the liver and lungs of the same animal 47.62 %, in goats the highest rate of the infection (60.84 %) was in the liver while in cattle the lung was the predominant site for hydatidosis in which the rate of infection was 50 %. The liver to be the predominant site of HC, because liver is the first filter in the body and also it acts as a first barrier for oncosphere after penetrating the intestinal mucosa to reach the portal circulation to be carried with blood stream to all parts of the body in addition to the large size of the oncosphere, therefore most of them are settled in the liver (Salih et al., 1993).

Table 2.

Organ specificity of HCs in sheep, goats and cattle slaughtered at Duhok abattoir

3.3. Types of cysts

The prevalence of HCs was noted on the basis of fertile, sterile and calcified as shown in Table (3). In sheep, total of 50 hydatid cysts were examined, the number of fertile cysts was higher (64%) than the sterile and calcified cysts which was 22% and 14%, respectively. In goats, while examines a total of 32 HCs it has been found the number of the fertile cyst was also higher (50%) than the sterile and calcified cysts (31.25% and 18.75%), respectively. In cattle total of 31 HCs were examined, the number of sterile cysts was higher (67.74%) than the fertile and calcified cysts (29.03% and 3.22%), respectively.

In the present study, the majority of sheep HCs was fertile (64%) the highest from goats and cattle HCs. Similar pattern of cyst type has been observed by Mohamad et al. (2008), Hama (2013) and (Mero et al., 2014) in Suleimani province. The high fertility rates of sheep HCs indicate that this animal has an essential role for perpetuation of the life cycle and spread of the disease.

Table 3.

The prevalence of various types of HCs in different animals slaughtered in Duhok abattoirs

3.4. The gender of animals:

Table (4) showed the prevalence of HCs in slaughtered animals according the sex, in sheep and goat was found the female were higher infection rates (28.99 and 24.24%) than male (1.57 and 2.51), respectively. while in cattle the infection rates were found only in male was 0.17%. in this aspect the present results similar with other studies involving the same intermediate host, as most of them reported higher prevalence in females (Daryani et al., 2007, in Iran; Kamhawi et al., 2009 in Jordan; Hama, 2013, and Sargali and Mero, 2013, in Iraq). While it is disagreed with (Meerkhan et al., 2018) in Duhok, was reported higher prevalence in males. However, (Mero et al.,2014) in Sulaimani province, found that the sex of the slaughtered animals has no significant effect on the distribution of CE, as the prevalence in males and female’s sheep, goats and cattle were very closed.

Table 4.

Prevalence of HCs in sheep and cattle slaughtered at Duhok abattoir according to gender

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