Echinococcosis: Past and Present Situation in Southeast Asia

*Triwibowo Ambar Garjito, Mujiyanto Mujiyanto and Mohammad Sudomo*

## **Abstract**

In Asia, Southeast Asia is reported as a non-endemic area of the parasite. However, several indigenous echinococcoses in human and animals were reported in several countries, such as Malaysia, Thailand, the Philippines, Indonesia, Vietnam, Cambodia, and Lao People's Democratic Republic (PDR). Most human infections are caused by *Echinococcus granulosus* and only two cases with *E. ortleppi.* There was no evidence case with *E. multilocularis* in Southeast Asia. *Echinococcus granulosus* infection is prevalent in areas that association with dogs and livestocks that close contact with dogs. The incidence is very low. A total of 49 cases of echinococcosis was identified in Southeast Asia from 1885 to 2015. Of which, at least 31 cases were indigenous, 14 cases were imported, and 4 cases were unknown. Thailand is the most prevalent country with echinococcosis in human, followed by very low incidence in Indonesia, Malaysia, Vietnam, the Philippines, Cambodia and Lao PDR. However, it is very difficult to estimate the real number of human echinococcosis case in Southeast Asia due to the long asymptomatic period that is usually >5 years. The disease may be more prevalent in Southeast Asia; however, they were underdiagnosed and not reported.

**Keywords:** echinococcosis, Southeast Asia, *Echinococcus granulosus*, *Echinococcus ortleppi*, incidence

#### **1. Introduction**

Echinococcosis (hydatidosis) is one of the neglected zoonosis caused by adult or larval stage of the cestodes belonging to the genus *Echinococcus* of the family Taeniidae [1–3]. At least nine species of *Echinococcus* have been recognized, including *Echinococcus granulosus* sensu stricto (GI [sheep strain], G2 [Tasmanian sheep strain], G3 [buffalo strain]), *E. equinus* (G4), *E. ortleppi* (G5), *E. canadensis* (G6–G10), *E. vogeli*, *E. oligarthrus*, *E. multilocularis*, *E. shiquicus* and *E. felidis.* Three among them, *E. granulosus*, *E. multilocularis*, and *E. ortleppi*, have a medical importance and cause alveolar echinococcosis (AE) and cystic echinococcosis (CE) [4–6]*.* Human alveolar echinococcosis has limited distribution in the northern hemisphere, while cystic echinococcosis is more widely distributed and cosmopolitan, particularly in countries of the temperate zones.

Southeast Asia is reported as non-endemic area of the parasite. However, several indigenous echinococcoses in human and animals were reported in several countries, such as Malaysia, Thailand, the Philippines, Indonesia, Vietnam, Cambodia,

and Lao People's Democratic Republic (PDR). Although the surveillance of echinococcosis was not routinely conducted in several countries and the cases were scarcely reported in Southeast Asia. In the recent years, by clinical, radiological, microscopic, and serological aspects, the disease was found in many areas in this region. This situation makes us alert on the possibility of echinococcosis as one of the potential health problems in the Southeast Asia.

Netherlands Indies [15]. In 1947, a total of 45 cysts of *Echinococcus unilocularis* (*E. granulosus*) were found in the lungs, kidney, stomach wall, and liver on an old monkey *Cynopithecus niger* (later on as *Macaca tonkeana*) from Sulawesi (Celebes) that suddenly died. The first evidence of *E. granulosus* infection in domestic dogs in Indonesia was reported from the Lindu Valley, Central Sulawesi, in 1972. The dog died suddenly after 18 months with numerous necropsies due to *E. granulosus.* Subsequent dog with echinococcosis was reported on the shore of Lake Lindu at Tomado village in 1973. The positive eggs of *E. granulosus* were confirmed by direct

*Echinococcosis: Past and Present Situation in Southeast Asia*

*DOI: http://dx.doi.org/10.5772/intechopen.89908*

smear and formaldehyde-ether from the dog stools. The adult worms of *E.*

ern, central, and southern regions of Thailand [17–19].

after infection and treatment in 2000 [18, 29].

now [13].

**3. Thailand**

echinococcosis.

**15**

*granulosus* were also identified during the study. The worms were collected from a dead dog on the shore of Lake Lindu at Tomado [16]. Since then, hundreds of dogs have been examined to identify the infection rate of *E. granulosus* in this area. However, hydatid cysts and adult *E. granulosus* have not been discovered until

In Thailand, at least 18 reports of echinococcosis were confirmed in indigenous Thai population, 5 cases were recorded from imported echinococcosis, and other 4 cases were noted with unknown origin during 1936–2007 [17–19]. Almost all cases were recorded as cystic echinococcosis, and only two cases were identified as alveolar echinococcosis [20–25]. Indigenous cases are distributed from the north-

The disease infection was reported for the first time in this country in 1936 from a 52-year-old male with peritoneum infection in Chiang Mai. The patient finally died due to severe infection without surgical removal and antiparasitic drug [25]. Subsequently, human case of echinococcosis was found in a 16-year-old male with *E. granulosus* cysts infection in lung in 1952. He is an Indian citizen who previously lived in India. He was diagnosed with echinococcosis while in Bangkok [20]. Another patient, a Thai female, aged 56 years, with lung infection was confirmed to be echinococcosis in 1980 [26]. Infection of *E. granulosus* cysts in the lung is a common manifestation in Thailand. Five other cases of lung echinococcosis, two females and three males with an age range of 32–71 years old, were also confirmed in between 1980 and 1995 [17, 18, 20–22, 27, 28]. Surgical removals were performed

in all patients, and two of them received antiparasitic drug treatment with

other two were identified from non-Thai citizens who previously lived in Middle East countries. Middle East countries are known as an endemic area of

albendazole. Two cases with renal echinococcosis were subsequently reported in a 39-year-old woman in 1993 and 43-year-old man in 1997. The first patient has recovered after marsupialization; however the second patient died several years

The most frequent echinococcosis case in this country is liver infection. At least 12 cases were reported in the period 1960–2007 [18, 19, 23, 27, 30, 31]. Two cases, 50-year-old male and 50-year-old female, were reported as Thai citizens who had a history of visiting the Middle East in 1994 and 1996, respectively [17, 18], while the

Liver echinococcosis was also reported in a Thai citizen who had a history of traveling to Switzerland in 2004. One subsequent case was recognized as a Nepali citizen who was visiting Thailand in 1995, while three cases were recorded as unknown origin in 1994 and 2004 [30]. In 2007, two cases were reported with echinococcal cystic mass in the liver that was diagnosed through serological testing using an indirect enzyme-linked immunosorbent assay (ELISA) [19]. Physical
