Hydatidosis or Cystic echinococcosis (CE ) is an important zoonotic disease that
constitutes a major public health problem in many countries around the world.1
The disease is concentrated in the sheep-raising and pastoral areas. Although
hydatid disease has been entirely eradicated in some countries, it remains a
serious endemic health problem in certain parts of the world such as the Middle
east, Mediterranean area, South America and Australia. 2.3
In Yemen,
hydatid disease is still endemic and hepatic hydatid cyst represents a major
health problem.4,5 This study aims to detemine the magnitude of the
problem of CE in patients attending Public and Private Hospitals at Sana’a city,
Yemen
METHODS
Yemeni hospitals both public and private in Sana’a city attract patients from all
over the country. In this descriptive study, complete medical history of all CE
patients were collected and analyzed.
The study included patients attending the outpatient and inpatient departments of
surgery at Yemeni public and private hospitals in Sana’a city.
CE
patients were diagnosed by various imaging techniques, including US, CT, X-ray
and MRI for a period of seven months between August 2006 and February 2007.
Detection and removal of the cysts through operation as well as microscopic
examination of the aspirated hydatid fluid were confirmatory. The ethics
committee approved the study and
informed consent was obtained from all participants.
RESULTS
A total of 66 CE patients were identified. They include 22 males (33%) and 44
females (67%) aged between 5 years to >30 years. The majority of the patients
were >30 years old (40.4%) and public hospitals had a higher proportion of
infected people (79%) than private hospitals which accounted for only 21%. (Fig.
1)

The features of the cysts (site, number and size) were identified and are presented in
Table 1 and Fig. 2. With regards to the number of cysts, 40 patients (61%) had a
single cyst in each effected organ while 26 patients (39%) had multiple cysts
(Fig. 2). Cysts less than 5 cm were demonstrated among 4 patients (6%), while
cysts greater than 5 cm were detected in 62 patients (94%). (Fig. 2)

In terms of the site of the cysts and the affected organs, the results showed that, 38
patients (57.6%) had isolated hepatic hydatid cysts, while 17 patients (25.8%)
had isolated pulmonary hydatid cysts. Only three patients (4.5%) had combined
affected organ. The remaining 8 patients had hydatid cysts in the ovary (2
patients), kidney (2 patients), uterus (2 patients), brain (1 patient) and iliac
fossa (1 patient).
Table 1 shows that the most common affected site in the liver was the right hepatic
lobe (65.78%). In the lung, the right lobe was markedly affected (58.8%) than
the left lobe (1.1%).

DISCUSSION
Cystic Echinococcosis/hydatidosis is one of the most important zoonotic diseases in the
world. High parasite prevalence is found in the Middle East as well as Arabic
North Africa.6 In Yemen, hydatidosis is still endemic and amazingly
more prevalent in females than males, while hepatic cysts represent a major
health problem.4.5.7 A Survey study of the endoparasites of stray
dogs in Sana’a, Yemen showed that 57% of stray dogs were infected with
intestinal parasites especially
E. granulosus and the incidence of infection was 7.1%.7
In this present study, infected females (67%) were double the number of infected
males (33%). This finding is in agreement with other studies conducted in Yemen,
which reported that females were more exposed to echinococcal infection than
males.4,7 Additionally, in Morocco and Libya, as well as in China, it
was reported that females were more exposed to echinococcal infection than
males.8,9,10 On the contrary in Kyrgyzstan, it was reported that
males were more exposed to the infection than females.11 The
differences in reports could be attributed to the difference in socio-economic
and cultural status from country to country. It is not surprising in the Yemeni
community since a considerable proportion of females continue to have some
activities related to animal breeding and/or agriculture.
In the present study, the age of the majority of
identified patients was more than 30 years old (40.4%). Only three patients were
5 years old, two of whom had isolated pulmonary CE and one had isolated
hepatopulmonary CE. Several studies have demonstrated that CE sparked medical
attention in almost all ages, from below one year to over 75 years of age, and
the pattern of gradual increase in prevalence of CE with age is very general and has been observed in many endemic
countries.9,10,12,13
The majority of patients in the present study were
found in the public hospitals (79%), this could be attributed to the fact that
public hospitals have good facilities with sufficient equipment and staff.
It was observed that the most common affected organ
was the liver (57.58%), followed by the lung (25.75%). The higher rate of
hepatic infection may be attributed to the fact that the liver acts as the
primary filter in the human body and the lung is often thought to be the second filter.14
A similar picture of organ affection to this has been reported by other studies.
It was reported that the most frequent site of hydatid cysts was the liver
(50-70%) followed by the lung (20-30%) and less frequently, kidney, heart, bones
and elsewhere.10,15,16,17
In the present study, 40 patients (61%) had single
cyst in each affected organ while 26 patients (39%) demonstrated multiple cysts.
In addition, 4 patients (6%) had cysts sized less than 5 cm, while 62 patients
(94%) had cysts sized greater than 5 cm. These findings are in accordance with other studies published which reported
that the most common ultrasonographic features of hydatid cysts are their
spherical shape and the fact that they are unilocular.18,19 The
results showed that the less common features were either a multicystic
appearance, having a detached germinal layer or evidence of hydatid sand within
the cyst.12,18,19 The predominance of solitary and single organ
involvement over multiple organ involvement was noted in the present study. In
this respect, it is widely accepted that primary cysts are mostly solitary in
nature.20 However, in the present study, it was difficult to
ascertain whether multiple cysts are primary or secondary.
CONCLUSION
In conclusion, Hydatid disease is still an important health problem in Yemen
which needs to be studied further. Therefore, accurate information on the
distribution of the disease should be the first step for the control and
prevention of the disease. Moreover, it is necessary to investigate the role of
different intermediate hosts and the strains of E .granulosus in humans and
animals in each province.
|