The 14th Annual Workshop of the Regional Network on Asian Schistosomiasis and Other Helminth Zoonosis (RNAS+) workshop was successful held in Bogor, Indonesia on 13-15, 2014. Here is the summary for the country report at this workshop.
Schistosomiasis mekongi, opisthorchiasis viverrini, lymphatic filariasis, soil-transmitted helminthiases are still major zoonoses of public health importance in Cambodia. Schistosomiasis mekongi is endemic in 56 villages of 2 districts in Kratie, and 58 villages of 5 districts in Stung Treng. Approximately 82,000 people are at risk of infection. The current control strategies for schistsomiasis include annual MDA, health education, sentinel site surveillance, case detection and sanitation promotion. The elimination is expected to be achieved by 2016.
The disease burden due to O. viverrini infection is high in Cambodia. For example, the overall prevalence is more than 25% in Kampong Cham, Kandal, Takeo provinces. Preventive chemotherapy control is carried out in endemic settings and health education to provinces targeted. Expansive investigation is still going on in the suspected areas of eating undercooked/raw fishes.
Lymphatic filariasis was endemic in northern part. The fifth round of MDA was conducted in all endemic areas. The evaluation survey in 2010 showed that transmission of LF was 0.1 – 0.6% which is below critical levels and indicated no more MDA required. Transmission assessment survey (TAS) in 2012 showed the prevalence was 0%. In the coming two years, another assessment survey will be performed, health education will be continued, and verification dossier will be prepared in 2015/2016. The elimination of lymphatic filariasis in Cambodia will be achieved by 2016.
The control measures for soil-transmitted helminthiases include MDA twice a year and health education in schools. S. stercoralis is now recognized as an important infection in Cambodia. The prevalence and treatment trials are under way.
By the end of 2013, transmission interruption of schistosomiasis had been achieved in Shanghai, Fujian, Guangdong, Guangxi, Zhejiang provinces, transmission control in Sichuan, Yunnan, Jiangsu, Hubei provinces, and infection control in Anhui, Jiangxi, Hunan provinces. An integrated strategy with an emphasis on managing the source of infection had commenced in 2004. The number of estimated cases in 2013 have been decreased by 78.05% and the acute cases decreased by 98.90%, compared to 2004. The prevalence of schistosomiasis in cattle declined from 4.49% in 2004 to 0.29% in 2013. The nationwide transmission interruption is expected to be achieved by 2020 and schistosomiasis will be eliminated by 2025.
There is a complete reporting system and a sensitive monitoring system for schistosomiasis in China. Facing the dramatic decline in prevalence of schistosomiasis, the national network of reference diagnsosis lab is being established. The network is able to provide sample bank and technical support, as well as external quality control. LAMP is also applied to detection of infection both in snails and human.
In addition to the endemicity of schistosomiasis japonica, more and more imported schistosomiasis caused by other species were also reported and even the potential intermediate host of Biomphalaria has been established in Southern part of China. The related strategies are being made.
Schistosomiasis in Indonesia is caused by Schistosoma japonicum. The intermediate host is Oncomelania hupensis lindoensis. The current endemic areas are localized in Napu Valley (Poso District), Lindu Valley (Sigi District), and Bada Valley ( Poso District). The control measures include stool examination, malacology survey, rat survey, and MDA programs (PZQ treatment). The current challenges to schistosomiasis control are control of infected animals, low availability of przaiquantel, eradication of snail foci, rice field cultivation or plantation, difficulty to estimate the potential snail habitats. In coming years, Indonesia will make efforts to control transmission in definitive host animals, compile strategy to eradicate snails in large areas, conduct operational research of black plastic and niclosamide to control snails, and continue the geospatial epidemiology study.
Cysticerosis are important zoonotic disease in Indonesia. The survey in Way Kanan Disctrict of Lampung Province showed that the seroprevalence in pigs and wild boar was 1.78% and 1%, respectively. The parasitological examination in raisers of pigs showed the prevalence is 1.67%.
Japan has established a complete reporting system for infectious diseases, which supported by prevention law of infectious diseases and prevention law of food-borne diseases. More than 70 infectious diseases were reported through this system. According to the reports of parasitic diseases between 2001 and 2013, only amebiasis and anisakis occurred increasingly. Kudoa septempunctata and Sarcocystis fayeri are emerging pathogens since 2011.
Echinococcus multilocularis is an important zoonosis endemic in Hokkaido, Japan. A total of 499 cases were reported up to 2005. Both the number of human cases and infection rate of fox are increasing in recent years. The current control strategy for this disease is mainly screening and examination. All the residents above 9 years are targeted for screening by ELISA every five years. The sero-positive will be delivered with questionnaires and confirmed by WB and ultrasonography.
Schistosomiasis had been eliminated since mid-1970s and the intermediate host snails currently are limited to Kofu Basin and Obitsu Rriver. The existing area of distribution is around 1310 ha.
Soil-transmitted helminth, including Ascaris lumbricoides, Trichuris trichiura, hook worm, are mainly endemic in northern highland. In contrast, O. viverrini is highly endemic in central and southern part, and S. mekongi is currently only confined to islands in the most southern part. The existing control strategy for STH is deworming program in preschool children and school children (6-11 years). For preschool children, the MDA activities have been integrated into the national immunization programme. Since 2013 the MDA was expanded to cover children aged 12-14 years. MAD is also major strategy for O. viverrini and S. mekongi in Laos. For the former, the MDA was initiated since 2012 in 6 most highly endemic provinces. For schistosomiasis, MDA is the routine control measure and performed once per year since 2007.
Myanmar is new RNAS+ member since 2013. The representative reported the preliminary results of current projects. According to a survey on intestinal parasites among HIV-infected patients from a hospital, the helminth infection rate was 18.3%. Two cases of F. buski and one of Clonorchis sinensis were found. According another survey on residents around Inlay Lake, the seroprevalence of schistosomiasis was 23.8%. Five case of schistosomiasis and three cases of chlonorchiasis were also identified according a survey on burden of malaria and co-infection among pregnant women, which showed a helminthic prevalence of 25.57%. The prevalence of intestinal nematode was also considerable, e.g. Ascaris lumbricoides of 23%, Trichuris trichura of 12%, Hook worm of 11%, Strongoloides stercoralis of 3%, in a slum area of Yangon Region.
In Myanmar, an Integrated Neglected Tropical Diseases Control Program was initiated by WHO in 2011. The program includes mass deworming in school children and MDA for lymphatic filariasis with two drugs (DEC & Albendazole). However, there are still challenges to the disease control. For example, there exists technological gap, funding restraints, different ecological setting and biodiversity of parasitic infestation. Additionally, many parasitic diseases are not included in Diseases under National Surveillance, and hence there are no specific reports, returns and regular information on parasitic NTDs.
Schistosomiasis japonica affects almost all provinces in Mindanao, except the Sulu Rchipelago and Misamis Oriental). Recently a new focus was identified in most northern part of the Philippines. Finding and treating patients were once the main measures for schistosomiasis and MDA was commenced in 2000. Currently praziquantel are freely available to all residents aged between 5 and 65 years in endemic areas. However, the compliance of MDA was normally lower than 50% according to the study in nine endemic areas. The estimated prevalence was around 4% in endemic areas in 2010. The highest prevalence occurred in Oriental Mindoro, Sorsogon, Northern Samar, and Agusan Del Sur. The ongoing researches are focusing on the integrated control strategy and praziquantel treatment in pregnant women.
According to national survey of helminthiases in Thailand in 2009, O. viverrini is the most common helminth in human and the overall prevalence of is 8.7%, following by hook worm (6.5%), Strongyloides (1.7%), intestinal fluke (1.6%), Trichuris trichura (1.2%), Taenia (0.7%), Ascaris (0.5%), Echinococcosis (0.5%), others (0.01%). Most cases are distributed in the northeast Thailand; the overall prevalence is 16.6%. National liver fluke and liver cancer control campaign was initiated in August 2012. According to the estimation in 2014, the overall prevalence declined to 5.1% from 8.7% in 2009. The estimated number of infections was 3.5 million from 6.0 million in 2009. The number of province with a prevalence of > 20% decreased from 18 to 3. Health education has played a key role in the control of O. viverrini infection.
Liver fluke infections caused by C. sinensis and O. viverrini are common in Vietnam. Human cases have been reported from 30 provinces. The high-risk provinces are Hoa Binh, Yen Bai, Ha Noi, Nam Dinh, Ninh Binh, Thanh Hoa and involve 3 million people. The coming control measures are distribution of drug at commune health stations, performance of IEC method in endemic community, estimation of the prevalence ofClonorchis/Opisthorchis in some area where residents have habit of eating raw fish long time ago and treat for high risk people.
Fascioliasis are widely distributed in 51/63 provinces in the country. Thousands of human cases are reported every year and about 62% of them are female. The guideline for fascioliasis diagnosis and treatment was developed and approved by Ministry of Health in 2006 and health staffs at district & provincial level were trained. Health educations are also performed as a control measure. The next plan in the control of fascioliasis includes improvement of diagnostic and treatment process, implementation of pilot MDA in high risk population, collaboration with veterinary sectors, and health education.
Fifty of 63 provinces in Vietnam report human cases of cysticercosis. In 2004, Ministry of Health compiled and issued the guideline for diagnosis, treatment and prevention for taeniasis /cysticercosis. Information Education and Communication (IEC) materials was developed and distributed in some endemic area. The country also issued regulations on the order and procedures of quarantine of animals and animal products, and veterinary hygiene inspection in the slaughterhouse.
Paragonimiasis are mainly endemic in northern Vietnam. The current control strategies are active and passive detection of cases, health education. Pilot targeted treatment with PZQ was conducted in endemic areas in Lao Cai, Yen Bai and Lai Chau provinces, northern mountain areas in 2007. The mis-diagnosis of paragonimiasis with tuberculosis and lung cancer is a concern in disease control.
Lymphatic filariasis once prevailed throughout the country, particularly in northern part. The prevalence has decline dramatically recently. The Mf rate post MDA in 4 provinces of higher endemicity is zero. Transmission assessment survey in 2013 using ICT and BmR test showed no positive case. The second transmission assessment survey will be conducted at the beginning of 2015. The disease is expected to be eliminated by 2016.
Soil-transmitted helminthiases are endemic across the country, particularly in northern part. The deworming programme is ongoing targeting at school age children and pre-school aged children. High coverage rate was observed. Nevertheless, lack of effective surveillance and reporting system, limited funding and human resource are challenging the control of soil-transmitted helminthiases. Additionally, poor sanitation and reinfection are also playing roles in transmission.