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Hydatid Disease in the Central 
Region of Iran: A 5-year 
Epidemiological and Clinical 
Overview 

 
Aliasghar Farazi1*, Nader 
Zarinfar1, Farhad Kayhani2, 
Firoozeh Khazaie3 
 
1Infectious Disease Research Center, 
School of Medicine, Arak University of 
Medical Sciences, Arak, Iran; 
2Medical Student, Faculty of Medicine, 
Arak University of Medical Sciences, 
Arak, Iran; 
3Department of Disease Control and 
Prevention, Arak University of Medical 
Sciences, Arak, Iran 

*Corresponding author

 
Vol. 8, No. 1 (2019)   |   ISSN 2166-7403 (online)  
DOI 10.5195/cajgh.2019.364 |   http://cajgh.pitt.edu 

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Central Asian Journal of Global Health 
Volume 8, No. 1 (2019) |  ISSN 2166-7403 (online) | DOI 10.5195/cajgh.2019.364|http://cajgh.pitt.edu 

 
 

Abstract 

Introduction: Hydatid cyst is caused by an infection by the larval stage of Echinococcus granulosus. Patients with cystic 
echinococcosis often remain asymptomatic until the hydatid cysts grow large enough to cause symptoms and signs. The cysts grow 
in the course of several years before reaching maturity and the rate of growth depends on the location of the cyst.  
Methods: This study was conducted in the Central region of Iran and involved all patients diagnosed with hydatid disease from 
2012 to 2016 with the records identifed from 10 centers for disease control. Descriptive statistics including range and percentage 
were used in analyzing the patient characteristics.  
Results: Hydatid disease was confirmed in 84 cases. The mean age of patients was (23.1±5.1) years (range: 15-53 years) and 55.9% 
of cases were female. Single organ involvement was found in 86.9% of cases. 98.8% cases were successfully treated. The most 
common sites of infection were lung (42.9%), followed by liver (38.1%), and joint liver/lung (10.7%). The diagnosis was 
established by abdominal ultrasound, abdominal CT, and serology in all patients. The diagnosis was confirmed by histology in 80 
(95.2%) of cases. All of cases were treated with albendazole, and 80 (95.2%) of cases had surgical intervention. The prevalence of 
human hydatidosis in our study was 1.16 per 100,000 population.  
Conclusions: Hydatid disease is common in Iran and should be a focus of public health interventions. The organ sites affected in 
this study include lung and liver. 

Keywords: Echinococcus granulosus; Epidemiology; Hydatid disease 

Hydatid Disease in the Central 
Region of Iran: A 5-year 
Epidemiological and Clinical 
Overview 
 
Aliasghar Farazi1*, Nader Zarinfar1, 
Farhad Kayhani2, Firoozeh Khazaie3 
 
1Infectious Disease Research Center, School 
of Medicine, Arak University of Medical 
Sciences, Arak, Iran; 
2Medical Student, Faculty of Medicine, Arak 
University of Medical Sciences, Arak, Iran; 
3Department of Disease Control and 
Prevention, Arak University of Medical 
Sciences, Arak, Iran 

 

Research 

Introduction 

Echinococcosis is an infestation with a 
tapeworm of the genus Echinococcus1.  Echinococcosis 
has been recognized since 1950 as a public health 
problem. Echinococcosis is included in the list of 17 
neglected tropical diseases and in the list of priority 
neglected zoonotic diseases for which WHO advocates 
concerted control efforts. The vision of controlling, 
eliminating, and eradicating neglected tropical diseases 
has gathered momentum in recent years. Interventions in 
selected countries of Central Asia, North Africa, and 
Latin America for the control and elimination of the 
echinococcosis as a public health problem will be scaled 
up by 20202. Echinococcosis is an important 
socioeconomic and public health problem in many areas 
of the world. Iran is known as one of the endemic regions 
of E. granulosus with high rates of infection, especially 
in rural communities. Three known species of Echino-

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Variable Subgroup Males (n=37) Females (n=47) P-value * 
Location Urban 14(37.8%) 19(40.4%) 0.809 
 Rural 23(62.2%) 28(59.6%)  
Age group 0–20 10(27%) 11(23.4%) 0.772 
 21–40 20(54.1%) 29(61.7%)  
 >40 7(18.9%) 7(14.9%)  
Occupation Farmer 12(32.4%) 14(29.8%) 0.003 
 Housekeeper 3(8.2%) 18(38.3%)  
 Herdsman 14(37.8%) 5(10.6%)  
 other 8(21.6%) 10(21.3%)  
Organ involvement liver 14(37.8%) 18(38.3%) 0.452 
 lung 15(40.5%) 21(44.7%)  
 Liver + lung 3(8.2%) 6(12.7%)  
 Other organs 5(13.5%) 2(4.3%)  

        *Statistical analysis was performed using Chi-square. 
Table 1. Comparison of demographic characteristics of cases with hydatid cyst by sex in the Central region of Iran 

coccus are of medical importance in humans. These 
are E. granulosus, causing cystic echinococcosis 
(CE), E. multilocularis causing alveolar echinococcosis 
(AE), and E. vogeli. Echinococcus granulosus is the 
most prevalent form of these; E. multilocularis is rare but 
virulent, while E. vogeli is the rarest. The humans are an 
accidental intermediate host in echinococcosis by eggs 
ingestion. The eggs then release oncospheres in the small 
intestine where oncospheres migrate through the 
circulatory system and produce hydatid cysts in the liver, 
lungs, muscles, and other organs3.  The endemic areas are 
South America, New Zealand, southern parts of Africa, 
Middle East, Iceland, Australia, and Central Asia4-6.  The 
overall incidence of cystic echinococcosis in endemic 
areas ranges from 1-220 cases per 100,000 population, 
while the incidence of alveolar echinococcosis ranges 
from 0.03-1.2 cases per 100,000 population. The hydatid 
disease has the capability of infecting individuals of 
different races equally and its incidence does not vary 
between females and males7.  All common complications 
of hydatid disease are related to the enlargement of cyst 
and complications of surgical procedure8.  

Patients with hydatid disease are asymptomatic 
until hydatid cysts are sufficiently large to cause 

discomfort. The cysts grow in the course of several years 
before reaching maturity and the rate of growth depends 
on the location of the cyst. The hydatid cysts are 
commonly found in the liver and lungs but can also 
appear in any organ, including heart, bone, spleen, 
kidneys, and central nervous system. Rupture of the cyst 
is frequently caused by trauma and may cause mild to 
severe anaphylactic reactions and sometimes death9-11. 
There is a lack of information on the prevalence, 
epidemiology and clinical patterns of human hydatidosis 
in most provinces of Iran. Therefore, this retrospective 
study was conducted to determine the prevalence and to 
describe the clinical findings and outcomes of human 
hydatidosis in the Central region of Iran.  

 

Methods 

This study was conducted in the Central 
province of Iran and involved all patients diagnosed with 
hydatid disease from 2012 to 2016. All cases were 
identified by retrospective review of hospital records. 
Data on cases were obtained from registries in ten centers 
for diseases control of the central province of Iran, which 
has about 1,500,000 people, with about 23% of those

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This work is licensed under a Creative Commons Attribution 4.0 United States License. 

 
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of its D-Scribe Digital Publishing Program and is cosponsored by the University of Pittsburgh Press. 
 

Central Asian Journal of Global Health 
Volume 8, No. 1 (2019) |  ISSN 2166-7403 (online) | DOI 10.5195/cajgh.2019.364|http://cajgh.pitt.edu 

 
 

 

 

Figure 1. Absolute frequency of organ involvement in cases with hydatid cyst  

residing in rural areas.  Demographic data, clinical 
presentation, treatment received, and outcomes were 
extracted. The data were analyzed using SPSS 18 
software (SPSS, Inc., Chicago, IL, US) using simple 
descriptive statistics. Chi-square test was also used, and 
all statistical analyses were performed at 0.05 
significance levels. This study was given ethical approval 
by the medical research committee at Arak University of 
Medical Sciences (IR.ARAKMU.REC.1394.273). 

 

Results 

Hydatid disease was confirmed in 84 cases. The 
mean age of cases was (23.1±5.1) years (range: 15-53 
years) and 55.9% of cases were female, with the majority 
residing in rural areas. Single organ involvement was 
found in 86.9% of cases. The most common sites of 
infection were lung 42.9%, followed by liver 38.1%, and 
joint liver/lung 10.7% (Figure 1). The diagnosis was 
established by abdominal ultrasound, abdominal 
computerized tomography, and serology in all patients. 
The majority of cases were found in the age group of 21-
30 years. There were no significant differences between 
males and females in regards to location, age group, and 

organ involvement, except for occupation where 37.8% 
of infected males were herdsmen and 38.3% of infected 
women were housekeepers (p=0.003) (Table 1).  

The diagnosis was confirmed by histology in 
95.2% of cases. The prevalence of human hydatidosis in 
the Central region was 1.16 per 100,000 population. The 
prevalence of human hydatidosis in rural area was 2.96 
per 100,000 population; while it was 0.57 per 100,000 (P 
< 0.001) in the urban area. All patients were treated with 
albendazole, and 95.2% patients received surgical 
intervention. Duration of albendazole therapy was 
104.5±36.1 days (range: 28-180 days) and 98.8% cases 
were successfully treated. Lung cyst in one patient 
(1.2%) was ruptured and the patient died due to the 
anaphylactic reaction. 

For the diagnosis of the cyst, CT scan and 
ultrasonography were performed and revealed that 38.1% 
of cysts were ≥10 cm. The chief complaint in 46.4% was 
abdominal pain. Other complains were abdominal mass 
in 7.1%, dyspnea in 21.4%, icterus in 4.8%, chest pain in 
6%, dyspepsia in 3.6%, cough in 13.1%, heart pain in 
1.2%, and headache in 1.2% of cases. Nine patients 
(10.7%), had complicated hydatid cyst including rupture, 

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infection, and obstruction. The most frequent site of 
complication was liver.  

 

Discussion 

In the present study, a total of 84 human 
hydatidosis cases were studied. Females were found to 
have a higher infection rate of hydatid cyst (55.9%) than 
males (44.1%).  The prevalence of human hydatidosis in 
the Central region was 1.16 per 100,000 population. The 
prevalence of human hydatidosis in rural area was 2.96 
per 100,000 population and in urban area was 0.57 (P < 
0.0001).  Although progress has been made in some 
regions, substantial effort is still required to move cystic 
echinococcosis and alveolar echinococcosis forward, to 
mitigate the burden of these diseases. Interventions 
should be tailored to each target area or region and take 
advantage of new tools for diagnosis and control of the 
disease.  

The actual incidence of human hydatidosis in 
Iran is not precisely known. Hydatidosis must be 
considered as a public health problem in Iran because of 
its endemicity in our country12, 13. According to the 
results of our study, females were found to have a higher 
infection rate of hydatid cyst than males but the 
differences is not significant (55.9% versus 44.1% P = 
0.127). This finding is similar to other reports on hydatid 
cyst in Iran14-16 and consistent with other reports from 
other endemic countries in the Middle East17, 18. The rate 
of infection with hydatid cyst in any given group is 
determined by local customs involving contact with 
vegetables and soil that is contaminated with dogs’ feces 
and its rate is relatively higher in women19. Hydatid 
disease is generally considered to be a female's rural 
disease, seemingly because Iranian women, especially in 
rural areas, have more contacts with domestic animals 
and infected products. They also have more frequent 
contact with unwashed raw vegetables, which may have 
higher contamination level with Echinococcus eggs. 
Although different organs were affected by hydatid cyst, 

only 13.1% of cases had multi organs infections with 
most of them being hepatopulmonary infection.  These 
results are consistent with other published reports20. The 
age of cases ranged from 15 to 53 years and the highest 
rate of infection and complications were in patients of 20-
30 years of age. In some studies, the peak incidence of 
hydatid cyst in Iran was between 20 - 40 years old, since 
this age group has the most contact with livestock. On the 
other hand, original infection might have occurred in 
childhood, as hydatid cysts grow very slowly21. Clinical 
examination revealed that abdominal pain was the most 
common complaint and was present in 46.4% of the 
cases. Other most common complaints were dyspnea, 
cough, abdominal mass, chest pain, icterus, dyspepsia, 
heart pain, and headache, which was similar to previously 
studies from Iran22. The prevalence rate of human 
hydatidosis in Iran was reported to be 0.61-2 per 100,000 
population13 and in our study, the prevalence of human 
hydatidosis in Central Province was 1.16 per 100,000 
population.  

Surveillance data is fundamental in order to 
show the burden of disease and to evaluate progress and 
success of control programs. However, as with other 
neglected diseases which are affecting underserved 
population and remote areas data are scarce and more 
resources are required for the disease control programs. 
This study might potentially serve as baseline data for 
monitoring future changing trends of this infection, and 
thus may help us to design strategies and programs for 
hydatid disease control. 

 

Acknowledgements 

This paper is extracted from the final doctoral 
thesis of Medical student and hereby we thank the 
Deputy of Research of Arak University of Medical 
Sciences and Infectious Diseases Research Center for 
their support. We thank the physicians for referring cases 
and patients for their cooperation. 

 

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	Hydatid Disease in the Central Region of Iran: A 5-year Epidemiological and Clinical Overview
	Abstract
	Keywords: Echinococcus granulosus; Epidemiology; Hydatid disease
	Research

