Introduction

Hydatid cyst is one of the most common zoonotic diseases developed following larval stage of Echinococcus granulosus infection. This agent is a tapeworm parasite mainly living in the dog’s bowel and rarely in other carnivores. Human serves as a random intermediate host in the life cycle. Like sheep, goat and camel, human infection is occurred consuming parasite eggs with vegetables, dust, water and other substances contaminated with the dogs and other canines feces (Khalili et al. 2010; Fomda et al. 2015; Hamzavi et al. 2011; O’Hern and Cooley 2013; Geramizadeh 2013).

Hydatid cyst generally involves liver and lung. Clinical symptoms and pathology is depends on the degree of infection, size and the involved organ. About 1.12 per 100,000 populations is suffered from hydatid cyst but the exact prevalence is unknown because of ineffective diagnostic methods. It has been rarely found in spleen, thyroid, breast, kidney and cervical soft tissue. Most of patients are asymptomatic and incidentally diagnosed. Intra abdominal cyst rupture can lead to severe complications such as anaphylaxis and sudden death (Fomda et al. 2015; Sikó et al. 2013).

Hydatic cyst has worldwide distribution, but the most contamination has been reported from Mediterranean region, Middle East, South-America, Central America, Australia, Chile, Eastern Europe, New Zealand and parts of Western Africa. Because of close contact of a large part of Iranian society with dogs and herbivores during traditional husbandry, WHO has introduced Iran as a hyperendemic region for hydatid cyst (Khalili et al. 2010; Abdi et al. 2013). This disease is most common particularly in rural areas due to unsanitary livestock slaughtering. Incidence of disease is high in mountainous areas and is rare in south of Iran because of its high temperature (Ezatpour et al. 2015; Djuricic et al. 2010).

In average, 33 % of dogs were infected in Iran. The average contamination of slaughtered sheep, goats, cows, camels and bufflehead were 18, 35, 8, 11 and 5 % respectively. These prevalences are higher than those reported from Libya, Iraq, Egypt, Sudan, Greece, Italy, Morocco and many other countries (Yousefi 2007). Khalili et al. (2010) investigated 144 patients in Chaharmahal province during 1998–2007. Of them, 68 % were female and 65 % living in rural areas. In a study conducted by Akhlaghi et al. (2009) among 1100 referring to blood transfusion organization in Tehran (capital of Iran), 11.63 % of samples were infected with Hydatid cyst indicating presence of latent hydatid cyst among healthy population in the Iran’s Capital. Losses from the hydatid cyst infection are not only involved the animal products and their fertility rates, but also include different costs for diagnosis, disabilities and work absenteeism (Mousavi et al. 2012).

Due to the annual reports from northern parts of Iran and lack of relevant study in this field, this study aims to investigate the epidemiological and clinical characteristics of hydatid cyst cases diagnosed from 2009 to 2014 in Mazandaran province, Iran.

Materials and Methods

All required data in this descriptive study was obtained from the Mazandaran portal information of disease surveillance system of Iranian Ministry of Health, Treatment and Medical Education. These data included date of report (year/month), habitat (urban/rural), patient’s name, age, gender, nationality, address, date of onset, clinical symptoms at presentation, history of contact with dog, method of raw vegetable consumption, diagnostic method, number of cysts, involved organs and therapeutic method.

Collected data were entered into Excel spreadsheet and SPSS ver. 20 software. Incomplete records were repaired through contact with the patients or hospital documents. This study was approved by ethics committee of Mazandaran University of Medical Sciences. Names of patients were removed based on ethical consideration.

All information was described using percent frequency, mean, standard deviation. All analyses were performed using Chi-square and Fisher exact tests.

Results

During 2009–2014, 41 hydatid cyst cases had been identified most of which (12 cases) registered in 2010. Mean (SD) age of patients was 42.2 (17.2) years. Minimum and maximum ages were 6 and 72 years. Most of patients were female (63.4 %) and had just one cyst. The average number of cysts was 1.6 ± 0.8.

Frequencies of different clinical symptoms were splenomegaly in 3(7.3 %), chest pain in 1(2.4 %), abdominal pain in 13(31.7 %), coughing in 2(4.9 %), abdominal pain and splenomegaly in 8(19.5 %), splenomegaly, abdominal pain and chest pain in 1(2.4 %), splenomegaly, abdominal pain and cough in 3(7.3 %), chest pain and cough in 3(7.3 %) of patients. Totally, splenomegaly, chest pain, abdominal pain and cough were observed in 39 % (16/41), 26.8 %(11/41) and 24.4 %(10/41) of cases.

All female patients were housewives and 100 % of male patients were livestock, farmer and employee (p < 0.001). No significant difference was observed between genders with regard to splenomegaly, chest pain, abdominal pain, cough, residential area, dog contact, method of washing vegetables, number of cysts and involved organs (p > 0.05). Patient’s job, chest pain and cough, contact with dog, method of washing vegetables, number of cysts and involved organ, were not significantly differ between rural and urban residences (p > 0.05). Rural residences in compare with urban residences had significantly higher rates of splenomegaly (55 vs. 23.8 %; p = 0.04) and lower rates of ascites (55 vs. 85.7 %; p = 0.03). Table 1 illustrates more details of clinical and epidemiological characteristics of patients with hydatid cyst.

Table 1 Distribution of epidemiological and clinical characteristics of patients infected Hydatid in north of Iran
Full size table

Discussion

Our study investigating the clinical and epidemiological features of patients with hydatid cyst in northern part of Iran (Mazandaran province), showed that this infection is more common among females, those over 30 years and housewives. In addition, most of patients had history of washing vegetables only with water without disinfectants. Radiology and computed tomography were the main diagnostic procedures and majority of patients undergone both surgery and chemotherapy. Moreover, liver was the most involved organ.

Several studies carried out in Chaharmahal province (southeast of Iran), West Azarbaiejan (northwest of Iran) and East Azarbaiejan (northwest of Iran) reported that Hydatid cyst infection prevalence was more in females that males (Khalili et al. 2010; Hajipirloo et al. 2013; Aslanabadi et al. 2013). Other studies in different parts of Iran such as Isfahan (Mohajeri et al. 2011), Ardabil (Heidari et al. 2011), Kashan (Esmaeili and Arbabi 2010) reported higher rates among women. In a study conducted in Turkey among 119 patients with hydatid cyst, 52.9 % of them were male (Aksu et al. 2013).

The age pattern observed in this study was in accordance with those reported in other studies. In Qom, the age range of patients was 8–69 years (Rezaei et al. 2014). In Chaharmahal (Khalili et al. 2010), North-Khorasan (Salehi et al. 2013) and Ardabil (Mirzanejadasl and Fasihi Herandi 2008) provinces, the most prevalences were found among 27–41, 31–40, 40–59 years age groups respectively. Mean age of patients in Isfahan province was 34.3 years (Mohajeri et al. 2011). Studies conducted in other countries showed that young people were the most infected groups. The peak of incidence in Romania was occurred among people aged between 11 and 14 (Cobzaru et al. 2013). In China, seropositive rates of Echinococcus among children and adults were reported as of 0.9 and 0.5 % respectively (Huang et al. 2013).

Results of the current study showed higher rates of infection among housewives. That was similar to those reported by Khalili et al. (2010) in Chaharmahal province (60 %) and Rezaei et al. (2014) in Qom (center of Iran). Prevalence of disease among rural residences in Chaharmahal (Khalili et al. 2010), West Azarbaiejan (Hajipirloo et al. 2013) and Romania (Cobzaru et al. 2013) were 65, 63.1 and 79 % respectively which are in accordance with our results, while, 90 % of patients in Qom province living in urban areas (Rezaei et al. 2014).

Most of studies investigated the prevalence of hydatid cyst, showed liver as the most organ involved (Khalili et al. 2010; Hajipirloo et al. 2013; Rezaei et al. 2014; Salehi et al. 2013; Cobzaru et al. 2013; Talaiezadeh and Maraghi 2006) similar to the current study. Only two studies carried out in North West of Iran and Bulgaria indicated that, lungs had been affected more than the other organs (Aslanabadi et al. 2013; Jordanova et al. 2015). Although, these studies were conducted among children. In Isfahan, among 47 patients undergone computed tomography, radiologic characteristics of simple cysts were observed in the results of 25 cases (Mohajeri et al. 2011).

We did not find any association between hydatid cyst and dog contact. Conversely, in Meshkin-shahr of Ardabil, incidence of disease among those were in contact with dogs were higher (Heidari et al. 2011). In another study carried out in Moghan of Ardabil, prevalence of developing hydatid cyst was higher in dog sites than other places (Mirzanejadasl and Fasihi Herandi 2008). Moreover, in Bulgaria, it has been shown that 90 % of affected children had been exposed to dogs (Jordanova et al. 2015). In China, seropositive rate of Echinococcus antigen among dogs was 0.9 % (Huang et al. 2013).

The present study provided evidences of epidemiological and clinical of patients infected hydatid cyst in North of Iran with using of existence data.

Small sample size is one of the main limitations of our study. It caused that the differences were not statistically significant in spite of considerable variations between the distributions of variables. Another limitation was lack of risk factor assessment due to the absence of control group.

This study showed than women were at higher risk of developing hydatid cyst maybe due to more exposure to parasite through vegetables. Also, present study indicated the liver as the most affected organ in hydatid cyst patients.

According to the above results, it is recommended to disinfect vegetables before use. Hands should not be in contact with mouth during disinfection and should be completely washed after sterilization. Humans are better to prevent unprotected exposure to dogs and children be prevented from permanent play with dogs. It is also suggested for dogs to be screened regularly regarding echinococcal infection.