Let's 'cut to the chase' on malaria elimination in the Greater Mekong Subregion.

The Greater Mekong Subregion has made remarkable progress towards eliminating malaria in recent years, but efforts are now faltering in some areas. The development of tools to control forest-based transmission is taking too long and efforts to control malaria among high-risk mobile people are failing. If countries are to meet their elimination targets and prevent the spread of multidrug-resistant falciparum malaria, urgent and radical changes will be required. This commentary proposes changes in the approach to the development and roll-out of new tools as well as changes to the management of elimination efforts targeting transmission in forests and forest-farms.

Proteomic and immunomic analysis of Schistosoma mekongi egg proteins.

Schistosomiasis remains a global health problem. In the Mekong river basin, approximately 80,000 people are at risk of infection by Schistosoma mekongi. The parasite's eggs become entrapped in the host's organs and induce massive inflammation, contributing to the pathogenesis of schistosomiasis. In addition, egg antigens are important in circumoval precipitin tests (COPTs) and other diagnostic techniques. Little is known regarding the egg proteins of S. mekongi, and so we applied immunoblotting and mass spectrometry-based proteomic approaches to study these proteins and their antigenicity. A total of 360 unique proteins were identified in S. mekongi eggs using proteomic analyses. The major protein components of S. mekongi eggs were classified into several groups by functions, including proteins of unknown function, structural proteins, and regulators of transcription and translation. The most abundant proteins in S. mekongi eggs were antioxidant proteins, potentially reflecting the need to neutralize reactive oxidative species released from host immune cells. Immunomic analyses revealed that only DNA replication factor Cdt1 and heat shock protein 70 overlap between the proteins recognized by sera of infected mice and humans, illustrating the challenges of knowledge transfer from animal models to human patients. Forty-one immunoreactive protein bands were recognized by either mouse or patient sera. Phosphoglycerate kinase, fructose-1,6-bisphosphate aldolase and elongation factor 1 appeared to be interesting immunogens of S. mekongi eggs as these proteins were recognized by polyclonal IgMs and IgGs in patient sera. Our findings provide new information on the protein composition of S. mekongi eggs as well as the beginnings of a S. mekongi immunogen dataset. These data may help us better understand the pathology of schistosomiasis as well as natural antibody responses against S. mekongi egg proteins, both of which may be useful in including S. mekongi to other schistosoma diagnostic, vaccine and immunotherapy development.

The role of domestic dogs in the transmission of zoonotic helminthes in a rural area of Mekong river basin.

Dogs have been bred since ancient times for companionship, hunting, protection, shepherding and other human activities. Some canine helminth parasites can cause significant clinical diseases in humans as Opisthorchis viverrini causing cholangiocarcinoma in Southeast Asian Countries. In this study, socio-cultural questionnaire, canine parasitological analysis, necropsy, parasite molecular confirmation and dog roaming data were evaluated in Savannakhet, Lao-PDR, a typical Mekong Basin area. Dog owners comprised 48.8% of the studied population, with 61.2% owning one dog, 25.1% 2 dogs, 8.5% 3 dogs and 1.8% owning more than 4 dogs. Data from GPS logger attached to dogs showed they walked from 1.4 to 13.3 km per day, covering an area of 3356.38m2 average, with a routine of accessing water sources. Thirteen zoonotic helminth species were observed. Causative agents of visceral and cutaneous larva migrans occurred in 44.1% and 70% of the samples respectively. Spirometra erinaceieuropaei was detected in 44.1% of samples. Importantly, O. viverrini was found in 8.8% of samples. Besides the known importance of dogs in the transmission of Ancylostoma spp., Toxocara spp. and S. erinaceieuropaei, the observed roaming pattern of dogs confirmed it as an important host perpetuating O. viverrini in endemic areas; their routine access to waterbodies may spread O. viverrini eggs in a favorable environment for the fluke development, facilitating the infection of fishes, and consequently infecting humans living in the same ecosystem. Therefore, parasitic NTDs control programs in humans should be done in parallel with parasite control in animals, especially dogs, in the Mekong River basin area.

The current status of opisthorchiasis and clonorchiasis in the Mekong Basin.

This review highlights the current status and control of liver fluke infections in the Mekong Basin countries where Opisthorchis and Clonorchis are highly endemic. Updated data on prevalence and distribution have been summarized from presentations in the "96 Years of Opisthorchiasis. International Congress of Liver Flukes". It is disturbing that despite treatment and control programs have been in place for decades, all countries of the Lower Mekong Basin are still highly endemic with O. viverrini and/or C. sinensis as well as alarmingly high levels of CCA incidence. A common pattern that is emerging in each country is the difference in transmission of O. viverrini between lowlands which have high prevalence versus highlands which have low prevalence. This seems to be associated with wetlands, flooding patterns and human movement and settlement. A more concerted effort from all community, educational, public health and government sectors is necessary to successfully combat this fatal liver disease of the poor.

Raw attitudes, wetland cultures, life-cycles: socio-cultural dynamics relating to Opisthorchis viverrini in the Mekong Basin.

Opisthorchis viverrini is one of the most common and medically important food-borne parasites in the Lower Mekong area of Southeast Asia. As we learn more about its ecology, pathology and epidemiology we see the need to consider more deeply the socio-cultural dynamics with which food-borne species complexes are associated. This paper argues that the Mekong region is characterized by strong livelihoods and life-style associations within wetland ecosystems, which are inseparable from human eating habits ("raw attitudes"). Within the fish-rice economies of the region there are many long-cherished food cultures based on eating raw, semi-cooked and fermented fish dishes, which are known to lead to opisthorchiasis, and potentially cholangiocarcinoma. This paper examines evidence from northeast Thailand showing that dedicated health outreach campaigns do help to reduce prevalence of opisthorchiasis over time. For disease prevention and health education approaches to be most effective, they must be sensitive to culture, livelihood economics, gender, and age. Further integrative, inter-disciplinary and international research must incorporate the complex dynamics of parasite ecology, human behavior, socio-economics, and public health awareness.

Spatio-temporal analyses of highly pathogenic avian influenza H5N1 outbreaks in the Mekong River Delta, Vietnam, 2009.

This paper presents the results of spatio-temporal analyses and epidemic modelling of HPAI H5N1 outbreaks that occurred in four provinces of the Mekong River Delta, Vietnam between January and March 2009. Significant spatio-temporal interaction of disease risk was observed within a distance of 10 km and 12 days following the detected onset of clinical signs. We estimate that the household-to-household infection rate within a commune was approximately 50 times greater than the household-to-household infection rate between communes. Our findings show that the predominant mechanism of infection transfer was local spread. A comparison of disease control procedures and veterinary capacity in communes with relatively high and low infection rates should help to identify procedures essential for effective outbreak management in this area of Vietnam.

Program issues in delivering targeted STI services through the public sector in the Greater Mekong region.

This review discusses the delivery of targeted STI services for both female sex workers (FSWs) and other high-risk groups through the public sector in the Greater Mekong region. Vaginal discharge algorithms for the general population are also discussed. High STI rates that justify targeted interventions have been reported recently amongst FSW in Cambodia, Lao PDR and Vietnam. Such interventions need to take into account the different patterns of sex work in the three countries. In Cambodia, there are large numbers of brothel-based FSWs although this pattern is changing as more brothels are closed by the authorities. In Lao PDR, services targeted towards reducing the burden of HIV/STI in FSW/service women are probably best delivered through NGO-led clinics. In Vietnam, commune based district health centers appear to offer better services for FSW than STI clinics. Male clients of FSW are an important group to target, but reaching such a heterogeneous population is difficult. Provision of quality STI drugs to those places where men present with STI symptoms should be a priority. The optimal way to manage STIs in FSWs is still unclear in this region. Clinical and laboratory specialists are keen to promote laboratory tests for STIs but there is an over reliance on direct staining techniques. In areas with high STI prevalences, periodic presumptive treatment could offer an effective option to reduce STI levels in high-risk groups until syndromic management algorithms are evaluated for local use. Social patterns of sex work are changing continually and require close monitoring in the future so that services can be adapted to these changes.

Schistosomiasis in the Mekong region: epidemiology and phylogeography.

An account is given of progress made over the last 20 years in the study of Mekong schistosomiasis, causative agent Schistosoma mekongi (Trematoda: Digenea). Emphasis is given to the discussion of work concerning the origin and subsequent dispersal of S. mekongi and related taxa, including relevant snails. The role of such phylogeographical data in schistosomiasis control and the prediction of areas at risk is examined. New palaeogeographical models are reviewed in relation to traditional explanations for the biogeographic deployment of Southeast Asian Schistosoma and their intermediate hosts. The demographics and molecular ecology of Neotricula aperta (Gastropoda: Pomatiopsidae), the snail host of S. mekongi, are reviewed with particular reference to new models for the life cycle of this species and their importance in snail control. The use of population genetic data in the limitation of N. aperta populations is evaluated and strategies suggested for schistosomiasis control efforts directed against the intermediate host. Developments in the taxonomy of N. aperta, and related taxa, and changes in nomenclature are covered. The direction of future investigations into the problem of Mekong schistosomiasis is also discussed.