Assessing the impact of a joint human-porcine intervention package for Taenia solium control:Results of a pilot study from northern Lao PDR

Following confirmation that a remote village of approximately 300 inhabitants in northern Lao PDR was hyperendemic for the Neglected Tropical Disease Taenia solium, a pilot human-porcine therapeutic control intervention was implemented between October 2013 and November 2014. Mass drug administration with a three day albendazole 400 mg protocol was offered to all eligible humans in October 2013 and March 2014. At these times, and again in October 2014, eligible village pigs received the anti-cysticercosis TSOL18 vaccination and an oral dose of oxfendazole anthelmintic at 30 mg/kg, both repeated one month later. Community and individual human taeniasis prevalences were estimated via copro-antigen ELISA of volunteered human faecal samples prior to October 2013, and again in January 2015, in order to examine the short term impact of the intervention.</p

Large-scale survey for novel genotypes of Plasmodium falciparum chloroquine-resistance gene pfcrt

Background. In Plasmodium falciparum, resistance to chloroquine (CQ) is conferred by a K to T mutation at amino acid position 76 (K76T) in the P. falciparum CQ transporter (PfCRT). To date, at least 15 pfcrt genotypes, which are represented by combinations of five amino acids at positions 72-76, have been described in field isolates from various endemic regions. To identify novel mutant pfcrt genotypes and to reveal the genetic relatedness of pfcrt genotypes, a large-scale survey over a wide geographic area was performed. Methods. Sequences for exon 2 in pfcrt, including known polymorphic sites at amino acid positions 72, 74, 75 and 76, were obtained from 256 P. falciparum isolates collected from eight endemic countries in Asia (Bangladesh, Cambodia, Lao P.D.R., the Philippines and Thailand), Melanesia (Papua New Guinea and Vanuatu) and Africa (Ghana). A haplotype network was constructed based on six microsatellite markers located -29 kb to 24 kb from pfcrt in order to examine the genetic relatedness among mutant pfcrt genotypes. Results. In addition to wild type (CVMNK at positions 72-76), four mutant pfcrt were identified; CVIET, CVIDT, SVMNT and CVMNT (mutated amino acids underlined). Haplotype network revealed that there were only three mutant pfcrt lineages, originating in Indochina, Philippines and Melanesia. Importantly, the Indochina lineage contained two mutant pfcrt genotypes, CVIET (n = 95) and CVIDT (n = 14), indicating that CVIDT shares a common origin with CVIET. Similarly, one major haplotype in the Melanesian lineage contained two pfcrt genotypes; SVMNT (n = 71) and CVMNT (n = 3). In Africa, all mutant pfcrt genotypes were the CVIET of the Indochina lineage, probably resulting from the intercontinental migration of CQ resistance from Southeast Asia. Conclusions. The number of CQ-mutant lineages observed in this study was identical to that found in previous studies. This supports the hypothesis that the emergence of novel CQ resistance is rare. However, in the mutant pfcrt genotypes, amino acid changes at positions 72, 74 and 75 appear to have recently been generated at least several times, producing distinct pfcrt mutant genotypes. The occurrence of new mutations flanking K76T may yield stronger resistance to CQ and/or a higher fitness than the original pfcrt mutant

Endemicity of Zoonotic Diseases in Pigs and Humans in Lowland and Upland Lao PDR: Identification of Socio-cultural Risk Factors

In Lao People's Democratic Republic pigs are kept in close contact with families. Human risk of infection with pig zoonoses arises from direct contact and consumption of unsafe pig products. This cross-sectional study was conducted in Luang Prabang (north) and Savannakhet (central-south) Provinces. A total of 59 villages, 895 humans and 647 pigs were sampled and serologically tested for zoonotic pathogens including: hepatitis E virus (HEV), Japanese encephalitis virus (JEV) and Trichinella spiralis; In addition, human sera were tested for Taenia spp. and cysticercosis. Seroprevalence of zoonotic pathogens in humans was high for HEV (Luang Prabang: 48.6%, Savannakhet: 77.7%) and T. spiralis (Luang Prabang: 59.0%, Savannakhet: 40.5%), and lower for JEV (around 5%), Taenia spp. (around 3%) and cysticercosis (Luang Prabang: 6.1, Savannakhet 1.5%). Multiple correspondence analysis and hierarchical clustering of principal components was performed on descriptive data of human hygiene practices, contact with pigs and consumption of pork products. Three clusters were identified: Cluster 1 had low pig contact and good hygiene practices, but had higher risk of T. spiralis. Most people in cluster 2 were involved in pig slaughter (83.7%), handled raw meat or offal (99.4%) and consumed raw pigs' blood (76.4%). Compared to cluster 1, cluster 2 had increased odds of testing seropositive for HEV and JEV. Cluster 3 had the lowest sanitation access and had the highest risk of HEV, cysticercosis and Taenia spp. Farmers which kept their pigs tethered (as opposed to penned) and disposed of manure in water sources had 0.85 (95% CI: 0.18 to 0.91) and 2.39 (95% CI: 1.07 to 5.34) times the odds of having pigs test seropositive for HEV, respectively. The results have been used to identify entry-points for intervention and management strategies to reduce disease exposure in humans and pigs, informing control activities in a cysticercosis hyper-endemic village

A participatory Ecohealth study of smallholder pig system in upland and lowland of Lao PDR

Objective: To conduct baseline seroprevalence surveys of pig key zoonoses and evaluate public health risks of pig-raising & pork consumption in one upland and one lowland province, Lao PDR. Methodology: Baseline seroprevalence surveys were conducted in two provinces, Louangphrabang representative of ‘upland’ and Savannaket province for ‘lowland’. The selection of villages is based on the village human population data available from the 2005 National census and GIS data. The statistical programme was used to randomly select 30 villages weighted by human population for each Province. Per village, the village chief was interviewed to obtain general information about each village and fifteen pigs were randomly sampled and smallholder owners interviewed. Simultaneously 15 villagers were randomly selected, interviewed and blood sampled. The training and field activities done with integrated transdisciplinary approaches for district and provincial staff. Human and pigs tests for exposure to Taenia/Cysticercosis, Trichinellosis, Hepatitis E virus and Japanese encephalitis virus (Also in pigs: Erysipelas, CSF, FMD and PRRS). Result: Preliminary (unadjusted) seroprevalence results for the upland province have been determined while lowland results are pending. Statistical analysis will be undertaken to ascertain disease prevalence and provide indication of associated risks for zoonoses, production and environmental impacts with associated data from the questionnaires. Using Survet and MySQL programme on power calculation of 80%, 95% CI. P-values less than 0.05 will be considered to be statistically significant. Outputs: Baseline seroprevalence surveys & results of risk factor evaluation will assist with improvement of pig and human health by reducing risks of pig related zoonoses for farmers, villagers, consumers, traders and slaughterhouse workers. It is anticipated that this will guide future intervention studies and policy

A participatory ecohealth study of smallholder pig system in upland and lowland of Lao PDR

A cross-sectional study to determine baseline seroprevalence of key pig zoonoses and some of priority pig production diseases and to evaluate public health risks of pig-raising and pork consumption in one upland and one lowland province, Lao PDR. The surveys were conducted in two provinces, Louangphrabang representative of ‘upland’ and Savannaket province for ‘lowland’. The selection of villages is weighted by village human population derived from the 2005 National census and GIS data. Participatory questionnaire development and data storage was enabled by a new web based programme called SurVet. Humans were tested for exposure to Taenia/Cysticercosis, Trichinellosis, Hepatitis E virus and Japanese encephalitis virus (pigs: Trichinella, HEV, JEV, Erysipelas, CSF, FMD and PRRS). The training and field activities were done with integrated transdisciplinary approaches involving district and provincial staff, as well as students. Result: Provisional seroprevalence and relevant odds ratios show that the viral diseases Hepatitis E and Japanese Encephalitis are widespread in both provinces, but that the parasitic diseases cysticercosis and trichinellosis are more sporadic, the latter apparently associated more with educated males of certain ethnicities. There are also results pertaining to pig health diseases and associated management risks. Further potential for multivariate statistical analysis exists. Outputs: Through the identification of the spatial patterning of seroprevalence and risk factors associated with exposure to these diseases, the IEC materials such as posters and brochures on human health and animal health risk reduction have been developed and produced as well as guide future research and policy