Novel estimation of African swine fever transmission parameters within smallholder villages in Lao P.D.R.

African Swine Fever (ASF) disease transmission parameters are crucial for making response and control decisions when faced with an outbreak, yet they are poorly quantified for smallholder and village contexts within Southeast Asia. Whilst disease-specific factors - such as latent and infectious periods - should remain reasonably consistent, host, environmental and management factors are likely to affect the rate of disease spread. These differences are investigated using Approximate Bayesian Computation with Sequential Monte-Carlo methods to provide disease parameter estimates in four naïve pig populations in villages of Lao People's Democratic Republic. The villages represent smallholder pig farmers of the Northern province of Oudomxay and the Southern province of Savannakhet, and the model utilised field mortality data to validate the transmission parameter estimates over the course of multiple model generations. The basic reproductive number between-pigs was estimated to range from 3.08 to 7.80, whilst the latent and infectious periods were consistent with those published in the literature for similar genotypes in the region (4.72 to 6.19 days and 2.63 to 5.50 days, respectively). These findings demonstrate that smallholder village pigs interact similarly to commercial pigs, however the spread of disease may occur slightly slower than in commercial study groups. Furthermore, the findings demonstrated that despite diversity across the study groups, the disease behaved in a consistent manner. This data can be used in disease control programs or for future modelling of ASF in smallholder contexts.

Utilising abattoir sero-surveillance for high-impact and zoonotic pig diseases in Lao PDR.

National disease surveillance systems are essential to a healthy pig industry but can be costly and logistically complex. In 2019, Lao People's Democratic Republic (Lao PDR) piloted an abattoir disease surveillance system to assess for the presence of high impact pig diseases (HIPDs) using serological methods. The Lao Department of Livestock and Fisheries (DLF) identified Classical Swine Fever (CSF), Porcine Respiratory and Reproductive Syndrome (PRRS) and Brucella suis as HIPDs of interest for sero-surveillance purposes. Porcine serum samples (n = 597) were collected from six Lao abattoirs in March to December of 2019. Serological enzyme-linked immunosorbent assay (ELISA) methods were chosen for their high-throughput and relatively low-costs. The true seroprevalence for CSF and PRRS seropositivity were 68.7%, 95% CI (64.8-72.3) and 39.5%, 95% CI (35.7-43.5), respectively. The results demonstrated no evidence of Brucella spp. seroconversion. Lao breed pigs were less likely to be CSF seropositive (P < 0.05), whilst pigs slaughtered at <1 year of age were less likely to be PRRS seropositive (P < 0.01). The testing methods could not differentiate between seropositivity gained from vaccine or natural infection, and investigators were unable to obtain the vaccine status of the slaughtered pigs from the abattoirs. These results demonstrate that adequate sample sizes are possible from abattoir sero-surveillance and lifetime health traceability is necessary to understand HIPDs in Lao PDR.

Seroepidemiology of Foot and Mouth Disease using passive surveillance techniques in selected provinces of Lao PDR.

Foot and Mouth Disease (FMD) is a high-impact, contagious transboundary animal disease that is endemic in Southeast Asia. Abattoir samples were routinely collected in six selected provinces between March and December 2019. A total of 1280 samples of abattoir animals were tested for FMD Non-Structural Protein (NSP) antibodies to indicate natural infections. Overall, 22.8% were seropositive for FMD NSP antibodies while seroprevalence of cattle (n = 469), buffalo (n = 214), and pigs (n = 597) were 44.6%, 35.0%, and 1.3%, respectively. The highest seroprevalence destination province was Xiengkhouang (35.3% of 272 samples), followed by Savannakhet (27.0% of 244 samples). Risk factors for evidence of natural infection identified by a multivariate logistic regression model included age groups (p-value = 0.02) and origin provinces (p-value = 2.8 × 10-5) of the animals. There were significant differences of FMD NSP seroprevalence between age groups and origin provinces of the animals. The odds ratio of a seropositive result in the less than 1 year old group was 2.5 (95% CI; 1.4, 4.4) when compared to the 3-4 years old group, while the odds ratios for animals that originated from Khammouane and Xiengkhouang provinces were 4.5 (95% CI; 1.1, 18.7) and 2.4 (95% CI; 1.4, 4.1), respectively, when compared to Champasak province. Serotype-specific antibody ELISA for 44 NSP antibody-positive samples revealed evidence of FMD serotypes O and A virus circulation in some provinces. Despite the passive abattoir survey providing useful information on FMD virus previous exposure and geographic locations of the animals, timely information on FMD virus circulation and distribution is also crucial to an effective control program. Alternative approaches to increase the cost-effectiveness of the surveillance network are also discussed.

Investigating baseline red meat slaughter operator capacity and directions for development in Lao PDR.

A study of operator knowledge, attitudes and practices (KAP) in red meat slaughter premise operations in northern Laos was conducted and compared with international best practice, to inform future industry development. The survey interviewed 68 (of 94 possible participants) employees from all ten commercial slaughter premises in six districts in three northern Laos provinces. This was supported by observations of slaughter premises, processes and the conduct of personnel. Descriptive analysis and linear regression modelling identified significant KAP predictor factors, and a gap analysis supported or rejected inferences from the generally low KAP scores for human and animal health, animal welfare, good manufacturing practices (GMP), work conditions and economics. The median proportion of correctly/desirably answered knowledge-related questions was 35.2% (interquartile range [IQR] = 22.2-51.9%) with 27.3% (IQR = 15.9-31.8%) for the attitude-related questions and 21.4% (IQR = 14.3-35.7%) for the practice-related questions. Two districts had significantly lower KAP scores than other districts, and staff had the lowest and meat inspectors had the highest scores. This study indicates that the current KAP for red meat processing falls short of international standards and that training programmes on disease risks and prevention are important in facilitating red meat industry development.

Improving smallholder food security through investigations of carcass composition and beef marketing of buffalo and cattle in northern Lao PDR.

This study determined the carcass composition of Lao indigenous buffalo (Bubalus bubalis) and cattle (Bos indicus), then examined trends in bovine meat marketing following review of records of beef production and prices in the two major cities of Luang Prabang (LPB) and Xieng Khoung (XK) provinces in northern Laos. Samples from 41 buffalo and 81 cattle (n = 122) were collected from animals slaughtered in May-June 2014, with live weights, carcass weights and other carcass-related variables collected. The animals were classified into four age cohort groups (<2, 2-<4, 4-6 and >6 years) with quantitative and dichotomous qualitative traits determined. There were significant differences in buffalo and cattle predicted mean carcass weights between age classification categories (p = 0.003 and 0.001) but not in dressing percentages (p = 0.1 and 0.1). The carcass weight of buffalo was 104 (±23.1)-176 (±12.0) kg compared to 65 (±8.7)-84 (±6.5) kg of cattle, with dressing percentages of 37-40 and 39-42 %, respectively. Despite an average bovine meat price increase of 42-48 % between 2011 and 2013, there was a reduction in the numbers of large ruminants slaughtered in the surveyed cities of LPB (11 %) and XK (7 %), with bovine meat availability per person of 5.2-6.6 kg (LPB) and 3.0-3.8 kg (XK). Improving the sustainability of the bovine meat supply in Laos requires a systems approach involving improvements to animal health and production, livestock marketing, plus the critical development of improved slaughterhouse facilities enabling a meat-processing sector to emerge. This development pathway is of particular importance for building the capacity of Laos to reduce food insecurity and alleviate the poverty of its largely rural smallholder community.

Promoting transboundary animal disease risk management via a multiple health and husbandry intervention strategies in upland Lao PDR.

Surveys of smallholder farmer knowledge, attitude, practice (KAP) and income were conducted in 2011 and 2012 in five northern provinces of Lao People's Democratic Republic (Lao PDR; n = 200 farmers). Participating villages were classified as either from a livelihood development project (LV; n = 80 farmers) or a livestock research project that contained both 'high-intervention' (HI; n = 60 farmers) or 'low-intervention' (LI; n = 60 farmers) villages. Farmer training plus a suite of health and productivity interventions were implemented in HI sites; only vaccination was implemented in LI sites, whilst various interventions and limited vaccination were introduced to LV sites. Farmer interviews were conducted with survey questions on socioeconomic variables and KAP of large ruminant health and disease risk management, enabling determination of quantitative and dichotomous qualitative traits and comparison of results from HI, LI and LV villages. The average farmer income from sales of large ruminants in HI was USD 621, in LI was USD 547 and in LV was USD 225 (p < 0.001). The predicted mean of total knowledge scores (/42) in the 2012 survey in HI was 28, in LI was 22 and in LV was 17 (p < 0.001). We conclude that improved KAP of large ruminant health and production can be achieved by intensive training, although with some farmers yet to apply their knowledge on husbandry and biosecurity practices, continued learning support and closed linkage of research and development projects to improve extension capacity is recommended. This multiple participatory approach promoting biosecurity in addition to vaccination may provide a more sustainable pathway for the advancement of Lao PDR on the Progressive Control Pathway for foot and mouth disease control.

Prevalence and clinical impact of Toxocara vitulorum in cattle and buffalo calves in northern Lao PDR.

This study was completed to determine the prevalence and distribution of Toxocara vitulorum infection in cattle and buffalo calves and investigate its clinical impact in northern Lao PDR (Peoples Democratic Republic). The results aim to assist decisions on disease control measures that can contribute to increasing cattle and buffalo productivity within smallholder farming systems in tropical areas. A prevalence survey for T. vitulorum in buffalo and cattle calves aged <3 months was conducted between September 2009 and June 2010 in five provinces of northern Lao PDR using a two-stage sampling technique to select 69 villages and 899 calves, with faecal samples collected and examined for T. vitulorum eggs at a local laboratory. At the time of sampling, data on calf morbidity and anthelmintic treatment was also collected. Factors potentially associated with infection and severity of infection were analyzed at univariable and multivariable levels, using T. vitulorum status (positive/negative) and on the positive calves only, faecal egg count levels as outcome variables. The estimated prevalence of T. vitulorum in northern Lao was 22.6 % (95 % confidence interval [CI], 0.17-0.28), and 76.8 % of villages had at least one positive calf. Province was the only significant (p < 0.05) variable investigated associated with calf infection status. Species (buffalo) was the only variable significantly (p < 0.05) associated with higher egg per gram of faeces levels among infected calves. Prevalence in calves aged 1-21 days, the reported prepatent period, was 17.5 % (CI 0.11-0.24). Treatment levels were very low (8.2 %) and if treatment occurred it was mostly unsuccessful. The high and wide spread infection of T. vitulorum in cattle and buffalo calves identified in this survey is likely to result in suboptimal cattle and buffalo productivity. Improved management of T. vitulorum infection in cattle and buffalo calves in northern Lao PDR is indicated to reduce potential negative production impacts and enable more efficient development of large ruminant livestock industry as a pathway from rural poverty for smallholder farmers in northern Lao PDR. In addition to quantifying this disease problem in calves, the conduct of this applied participatory research study provided an important opportunity to improve animal health services by increasing the parasite, large ruminant handling and research knowledge and capacity of government animal health staff and farmers.

Evaluating serological tests for foot-and-mouth disease while accounting for different serotypes and uncertain vaccination status.

Controlling foot-and-mouth disease (FMD) by vaccination requires adequate population coverage and high vaccine efficacy under field conditions. To assure veterinary services that animals have acquired sufficient immunity, strategic post-vaccination surveys can be conducted to monitor the coverage and performance of the vaccine. Correct interpretation of these serological data and an ability to derive exact prevalence estimates of antibody responses requires an awareness of the performance of serological tests. Here, we used Bayesian latent class analysis to evaluate the diagnostic sensitivity and specificity of four tests. A non-structural protein (NSP) ELISA determines vaccine independent antibodies from environmental exposure to FMD virus (FMDV), and three assays measuring total antibodies derived from vaccine antigen or environmental exposure to two serotypes (A, O): the virus neutralisation test (VNT), a solid phase competitive ELISA (SPCE), and a liquid phase blocking ELISA (LPBE). Sera (n = 461) were collected by a strategic post-vaccination monitoring survey in two provinces of Southern Lao People's Democratic Republic (PDR) after a vaccination campaign in early 2017. Not all samples were tested by every assay and each serotype: VNT tested for serotype A and O, whereas SPCE and LPBE tested for serotype O, and only NSP-negative samples were tested by VNT, with 90 of them not tested (missing by study design). These data challenges required informed priors (based on expert opinion) for mitigating possible lack of model identifiability. The vaccination status of each animal, its environmental exposure to FMDV, and the indicator of successful vaccination were treated as latent (unobserved) variables. Posterior median for sensitivity and specificity of all tests were in the range of 92-99 %, except for the sensitivity of NSP (∼66%) and the specificity of LPBE (∼71 %). There was strong evidence that SPCE outperformed LPBE. In addition, the proportion of animals recorded as having been vaccinated that showed a serological immune response was estimated to be in the range of 67-86 %. The Bayesian latent class modelling framework can easily and appropriately impute missing data. It is important to use field study data as diagnostic tests are likely to perform differently on field survey samples compared to samples obtained under controlled conditions.

Retrospective investigation of the 2019 African swine fever epidemic within smallholder pig farms in Oudomxay province, Lao PDR.

The 2019 African swine fever (ASF) outbreak in the Lao People's Democratic Republic (Lao PDR or Laos) represented a major epidemiologic event where a transitioning lower-middle income nation (LMIC) experienced a viral epidemic in a naïve pig population. The diversity of pig management styles creates challenges for local and regional policymakers when formulating recommendations to control an ASF outbreak. The aim of this study were to investigate the management of pigs in villages of Oudomxay province that were affected by ASF in 2019, as a case study in a smallholder pig-rasing system in northern Laos. The frequencies of well known risk factors were measured in the affected villages and the timelines and household level stock losses due to the outbreak were investigated. These findings were compared to data available from a similar outbreak in the southern province of Savannakhet. Disease control implications of these findings are discussed. Mean losses were 3.0-23.3 pigs per household, with a mean lost herd value of USD 349, 95% CI (294-415). These pig losses reflect those estimated in Savannakhet (6.7 pigs per household). However, the financial loss estimated per household was higher, USD 349 versus USD 215, possibly due to higher pig values and a higher input/output management approach in Oudomxay. The investigation revealed the presence of numerous ASF risk factors, such as swill-feeding and free-ranging. In addition, poor biosecurity practices - such as inappropriate garbage disposal and slaughtering - that could contaminate the environment were present. ASF cases occurred across all villages between June and December 2019, with outbreak periods ranging from 22-103 days. These values are consistent with the outbreak in Savannakhet; however, notable differences in management styles were observed. These findings demonstrate the need for more disease control resources from the village to the Governmental level. Villages need support in enacting context appropriate biosecurity measures, whilst the ongoing surveillance and investigation of ASF require investment in logistical and veterinary resources at the Governmental level.

Significant mortality of large ruminants due to hypothermia in northern and central Lao PDR.

An extreme cold exposure event occurred between March 14th and 19th 2011 in northern and central Lao PDR resulting in a major mortality of cattle and buffalo. At least six northern and one central province reported losses, involving 46 districts and 1,384 smallholder farmers, with a total of 7,162 cattle and 3,744 buffalo reported to have died in association with cold weather. Affected animals were observed to shiver, display slow and shallow respiration, lose consciousness and eventually die. Many deaths occurred at night and were recorded in both sexes and all ages of large ruminants. However, mortalities occurred mostly in animals that were free-grazing in the forest and natural grassland, and exposed to the cold weather. Some housed animals that were provided with warmth from shelter and fires and supplementary feed did not die. Samples from dead animals collected for laboratory analysis confirmed that bacterial or viral pathogens were not present. The cause of the mortality was attributed to hypothermia, and the economic losses were estimated at USD 2,463,912.00. Xieng Khouang Province reported the most severe losses with deaths of 4,600 cattle and 1,665 buffalo. At Thong Haihin meteorological station in this province on March 16th and 17th 2011, minimum temperatures recorded were 6.7°C and 7.5°C and rainfall recorded was 36.6 mm and 61.7 mm, respectively. This was the first reported extreme cold event in living memory occurring between the end of dry season and beginning of the wet season in northern Laos. This event is reported in detail as it caused a major loss of wealth for poor smallholder farmers and indicates that strategies to minimise the impact of extreme cold weather events need to be included in livestock development extension programmes.

Socioeconomic impacts of clinical foot-and-mouth disease and a risk-based partial vaccination campaign for smallholders in Lao People's Democratic Republic.

Foot-and-mouth disease (FMD) is endemic in Lao People's Democratic Republic (PDR). A risk-based partial vaccination campaign was implemented in Champasak, Savannakhet and Xiengkhouang Provinces in Lao PDR in 2016-2020, which had limited effects on reducing the circulation of FMD virus. The objectives of this study were to measure the socioeconomic effects of (i) a clinical FMD occurrence and (ii) the vaccination campaign on livestock production performance of smallholders in Lao PDR in 2016-2020. Two questionnaire surveys were conducted at the beginning (2016) and the end (2020) of the campaign, involving 1609 smallholders in 160 villages comparing areas with and without FMD control. Mixed-effect multivariable regression models were fitted to measure the association between livestock production parameters at the household level (rates of birth, sale, purchase, and death, sale price, costs, gross gains and net gains) and (i) a clinical FMD occurrence and (ii) the vaccination campaign, while adjusting for village, herd size, province, vaccination status and FMD knowledge. We found no significant difference in annual household-level costs, gains and net gains by due absence of FMD. However, smallholders with FMD had a 52% higher cattle death rate, a 43% lower goat sale rate and a 78% lower pig sale price than those without FMD. Smallholders with FMD also had a lower purchase rate of livestock (cattle -15% and pigs -93%) compared with those without FMD. There was a general improvement in livestock production in target villages over the 5 years of the vaccination campaign, whereas there was an overall decline in non-target villages, resulting in USD 218 higher net gains in target villages in 2020 compared with non-target villages, possibly due to reduced severity of disease and improved awareness on FMD and general livestock health. The findings of this study will help improve strategies for sustainable and efficient FMD control in Lao PDR, while the challenges and importance of gaining participation by smallholders are highlighted.

Foot-and-mouth disease seroprevalence and reporting behaviours in nine northern provinces in Lao PDR: The current situation and challenges for control.

Foot-and-mouth disease (FMD), caused by the FMD virus (FMDV), is one of the most important of global livestock diseases, impacting even-toed ungulates and distributed mostly in less developed countries that are home to 75% of the human population. A progressive control pathway for FMD (PCP-FMD) was developed to assist countries to better manage FMD risks and progress towards control and eradication. This requires evidence of current FMD seroprevalence to enable the informed risk assessment and the disease control planning required to progress along the initial stages of the PCP-FMD. Despite Laos being an active member of the South East Asia and China FMD campaign, these data have been challenging to obtain. To address this gap, a cross-sectional seroprevalence study in nine northern Lao provinces was conducted in early 2019. The study sampled 602 large ruminants and 19 goats from 30 villages. Overall, the large ruminant seroprevalence was 43.7% (95% CI 39.7-47.8), and 90% of sampled villages had at least one seropositive animal. Large ruminants suspected of having had clinical FMD in their lifetime were found to have an increased risk of being seropositive (odds ratio 1.96, 95% CI 1.06-3.65, p = .03). An examination of current reporting behaviours of farmers, village veterinary workers and district and provincial officials found that individuals were using their discretion as to whether disease events required reporting along the chain of command. This, plus the lack of a computerized reporting system, contributed to a loss of historical data, potentially compromising progression on the PCP-FMD. Laos requires ongoing support from donor agencies to improve the current animal disease surveillance system and implement effective FMD control strategies that can enable progress on the PCP-FMD.

Abattoir-Based Serological Surveillance and Spatial Risk Analysis of Foot-and-Mouth Disease, Brucellosis, and Q Fever in Lao PDR Large Ruminants.

A national animal disease surveillance network initiated by the Lao PDR government is adopted and reinforced by a joint research project between the National Animal Health Laboratory (NAHL), the Department of Livestock and Fisheries (DLF), and the Mahidol Oxford Tropical Medicine Research Unit (MORU). The network is strengthened by staff training and practical exercises and is utilised to provide zoonotic or high-impact disease information on a national scale. Between January and December 2020, large ruminant samples are collected monthly from 18 abattoirs, one in each province, by provincial and district agriculture and forestry officers. The surveillance network collected a total of 4247 serum samples (1316 buffaloes and 2931 cattle) over this period. Samples are tested for antibodies against Brucella spp., Coxiella burnetii (Q fever) and Foot-and-Mouth Disease Non-Structural Protein (FMD NSP) using commercial ELISA kits and the Rose Bengal test. Seroprevalences of Q fever and brucellosis in large ruminants are low at 1.7% (95% CI: 1.3, 2.1) and 0.7% (95% CI: 0.5, 1.0) respectively, while for FMD NSP it is 50.5% (95% CI: 49.0, 52.0). Univariate analyses show differences in seroprevalences of Q fever between destination (abattoir) province (p-value = 0.005), province of origin (p-value = 0.005), animal type (buffalo or cattle) (p-value = 0.0008), and collection month (p-value = 3.4 × 10−6). Similar to Q fever, seroprevalences of brucellosis were significantly different for destination province (p-value < 0.00001), province of origin (p-value < 0.00001), animal type (p-value = 9.9 × 10−5) and collection month (p-value < 0.00001), plus body condition score (p-value = 0.003), and age (p-value = 0.007). Additionally, risk factors of the FMD NSP dataset include the destination province (p-value < 0.00001), province of origin (p-value < 0.00001), sex (p-value = 7.97 × 10−8), age (p-value = 0.009), collection date (p-value < 0.00001), and collection month (p-value < 0.00001). Spatial analyses revealed that there is no spatial correlation of FMD NSP seropositive animals. High-risk areas for Q fever and brucellosis are identified by spatial analyses. Further investigation of the higher risk areas would provide a better epidemiological understanding of both diseases in Lao PDR. In conclusion, the abattoir serological survey provides useful information about disease exposure and potential risk factors. The network is a good base for field and laboratory staff training in practical technical skills. However, the sustainability of such a surveillance activity is relatively low without an external source of funding, given the operational costs and insufficient government budget. The cost-effectiveness of the abattoir survey could be increased by targeting hotspot areas, reducing fixed costs, and extending the focus to cover more diseases.

Impact of risk-based partial vaccination on clinical incidence and seroprevalence of foot and mouth disease in Lao PDR.

Foot and mouth disease (FMD) is endemic in the Lao People's Democratic Republic (PDR) and it causes economic loss to smallholder husbandry systems. An intervention programme based on a risk-based partial vaccination strategy was implemented in three provinces of Lao PDR (Champasak, Savannakhet and Xiangkhouang) to immunise domestic cattle and buffalo during 2016-2020. Two cross-sectional surveys were conducted in 2016/17 and 2020 to evaluate the impact of the vaccination programme on the prevalence of FMD virus exposure and clinical incidence of the disease. A total of 212 villages were visited during the two surveys, collecting 1609 household-level questionnaire results and 5931 blood samples of domestic cattle and buffalo. Blood samples were tested for the presence of antibodies to the non-structural proteins of FMD virus, and seroprevalence of 42.5 and 47.5% in 2016/17 and 2020, respectively were found. Multivariable regression analysis indicated that the efficacy of the FMD vaccination programme for reducing FMD virus circulation varied by province. In general, the incidence of clinical FMD increased toward the end of the 5-year intervention period, coinciding with a reduction of vaccine coverage in the last 2 years of the period. The findings suggest that the risk-based vaccination strategy achieved a marginally protective effect against the circulation of FMD virus with the possible limiting factors being operational constraints of public veterinary services, lack of farmers' compliance and unsustainable funding. We conclude that consistent resource availability and higher vaccination coverage is required to successfully control FMD with a risk-based vaccination strategy in Lao PDR.

Changes in farmer animal health and biosecurity knowledge, attitudes and practices: Insights from Cambodia and Laos.

Livestock agriculture in Cambodia and Laos is severely affected by endemic and exotic transboundary animal diseases, impacting household livelihoods and food and nutritional security. Collaborative animal health and biosecurity projects were conducted in each country between 2015 and 2019 aimed at increasing smallholder livestock production through mainly knowledge-based interventions in large ruminant disease prevention, nutrition, reproduction and marketing access. This study's objectives were to identify baseline animal health and biosecurity knowledge, attitudes and practices (KAP) of farmers, and temporal changes in key attitudes and practices associated with improved knowledge. Data for each country were analysed separately, and a formal between-country comparison was avoided due to major implementation and management differences. Binomial logistic regression without random terms compared the overall knowledge scores between 2015 and 2018 in each country, and binomial logistic regression with random terms was used to investigate possible associations between animal health and biosecurity knowledge scores and attitudes and practices. In Cambodia, the average animal health and biosecurity knowledge score increased from 4.8 (±2.2)/17 in 2015 to 13.0 (±2.8)/17 in 2018 (p < .0001). In Laos, the average scores improved from 7.2 (±2.5)/12 in 2015 to 7.9 (±2.9)/12 in 2018 (p = .0003). Clinical signs of foot-and-mouth disease were accurately reported by 100% of Cambodian and 88% of Lao project farmers, and overall, attitudes and practices improved in both countries over the study period. The belief that vaccination can improve livestock value was associated with increasing knowledge in both countries (Cambodia: OR 1.45, 95% CI 1.24-1.68, p < .0001; Laos: OR 1.43, 95% CI 1.16-1.75, p = .0006) as was the use of the services of village para-veterinarians if they had better training (Cambodia: OR 1.76, 95% CI 1.20-2.58, p = .004; Laos: OR 2.02, 95% CI 1.19-3.41, p = .009). However, the source of livestock information (District veterinary officials) was the only practice associated with knowledge in both Cambodia and Laos. The influence of resource scarcity on farmer decision making and knowledge measures was considered of particular relevance to the findings.

The Development of an Abattoir-Based Surveillance System in Lao PDR for the Detection of Zoonoses in Large Ruminants: Q Fever and Brucellosis Seroepidemiology as a Pilot Study.

Although animal health surveillance programmes are useful for gaining information to help improve global health and food security, these programmes can be challenging to establish in developing economies with a low-resource base. This study focused on establishing a national surveillance system initiated by the Lao PDR government using a passive surveillance system of abattoir samples as a pilot model, and to gain information on contagious zoonoses, particularly Q fever and brucellosis, in the large ruminant population. A total of 683 cattle and buffalo samples were collected from six selected provinces of Lao PDR between March-December 2019. Out of 271 samples tested, six samples (2.2%, 95% confidence interval (CI) of 1.0, 4.8) were positive in the Q fever antibody ELISA test. Only one sample (out of 683; 0.2%, 95% CI 0.0, 0.8) tested positive to the Brucella antibody ELISA test. Seroprevalence of these important zoonoses in Lao PDR were relatively low in cattle and buffaloes; however, extensive animal movement within the country was identified which could increase risks of spreading transboundary diseases. The study highlights the importance of ongoing animal health surveillance and the need to find cost-effective approaches for its long-term sustainability.

The impact of African swine fever virus on smallholder village pig production: An outbreak investigation in Lao PDR.

African swine fever virus (ASFV) causes a deadly disease of pigs which spread through southeast Asia in 2019. We investigated one of the first outbreaks of ASFV in Lao People's Democratic Republic amongst smallholder villages of Thapangtong District, Savannakhet Province. In this study, two ASFV affected villages were compared to two unaffected villages. Evidence of ASFV-like clinical signs appeared in pig herds as early as May 2019, with median epidemic days on 1 and 18 June in the two villages, respectively. Using participatory epidemiology mapping techniques, we found statistically significant spatial clustering in both outbreaks (p < 0.001). Villagers reported known risk factors for ASFV transmission - such as free-ranging management systems and wild boar access - in all four villages. The villagers reported increased pig trader activity from Vietnam before the outbreaks; however, the survey did not determine a single outbreak source. The outbreak caused substantial household financial losses with an average of nine pigs lost to the disease, and Monte Carlo analysis estimated this to be USD 215 per household. ASFV poses a significant threat to food and financial security in smallholder communities such as Thapangtong, where 40.6% of the district's population are affected by poverty. This study shows ASFV management in the region will require increased local government resources, knowledge of informal trader activity and wild boar monitoring alongside education and support to address intra-village risk factors such as free-ranging, incorrect waste disposal and swill feeding.

Antimicrobial use and resistance data in human and animal sectors in the Lao PDR: evidence to inform policy.

OBJECTIVES: To review the scientific evidence base on antimicrobial use (AMU) and antimicrobial resistance (AMR) in human and animal sectors in the Lao PDR (Laos). METHODS: We reviewed all publications from July 1994 (the first article describing AMR in Laos) to December 2020. Electronic searches were conducted using Google Scholar and PubMed with specific terms relating to AMR and AMU in Lao, French and English languages. FINDINGS: We screened 1,357 peer-reviewed and grey reports by title and abstract and then full articles/reports. Of 80 included, 66 (83%) related to human health, nine (11%) to animal health, four (5%) to both animal and human health and one (1%) to the environment. Sixty-two (78%) were on AMR and 18 (22%) on AMU. Extended spectrum beta lactamase-producing Escherichia coli was the greatest concern identified; the proportion of isolates increased fivefold from 2004 to 2016 (2/28 (7%) to 27/78 (35%)) from blood cultures submitted to the Microbiology Laboratory, Mahosot Hospital, Vientiane. Carbapenem resistant Escherichia coli was first identified in 2015. Methicillin-resistant Staphylococcus aureus (MRSA) was uncommon, with 15 cases of MRSA from blood cultures between its first identification in 2017 and December 2020. AMR patterns of global antimicrobial resistance surveillance system (GLASS) target pathogens from livestock were less well documented. There were few data on AMU in human health and none on AMU in livestock. The first hospital AMU survey in Laos showed that 70% (1,386/1,981) of in-patients in five hospitals from 2017 to 2018 received antimicrobial(s). Antibiotic self-medication was common. CONCLUSION: AMR in Laos is occurring at relatively low proportions for some GLASS pathogens, giving the country a window of opportunity to act quickly to implement strategies to protect the population from a worsening situation. Urgent interventions to roll out new guidelines with enhanced one-health antibiotic stewardship, reduce antibiotic use without prescriptions, enhance surveillance and improve understanding of AMU and AMR are needed.

Detection of Foot-and-Mouth Disease Virus in the Absence of Clinical Disease in Cattle and Buffalo in South East Asia.

Foot-and-mouth disease virus (FMDV) is widespread throughout much of the world, including parts of South East Asia. Surveillance is often limited in endemic areas, relying predominantly on passive outbreak reporting. As part of the World Organisation for Animal Health (OIE)'s South East Asia and China Foot-and-Mouth Disease Project (SEACFMD), field sampling was performed to help understand evidence of widespread virus exposure observed in previous studies. Serum and dry mucosal swabs were collected to evaluate the presence of FMDV RNA on the nasal, oral, and dorsal nasopharyngeal mucosal surfaces of 262 healthy cattle (n = 84 in Laos; n = 125 in Myanmar) and buffalo (n = 48 in Laos; n = 5 in Myanmar) immediately following slaughter in three slaughterhouses. Swabs and serum were tested by the OIE/FAO World Reference Laboratory for foot-and-mouth disease (WRLFMD) using pan-serotypic real-time reverse transcription-PCR (rRT-PCR) and serum was evaluated using the FMD PrioCHECK non-structural protein (NSP) ELISA. In total, 7.3% of animals had detectable FMDV RNA in one or more of the three sites including 5.3% of nasopharyngeal swabs, 2.3% of oral swabs, and 1.5% of nasal swabs. No FMDV RNA was detected in serum. Overall, 37.8% of animals were positive for NSP antibodies, indicating likely past natural exposure to FMDV. Results were comparable for Laos and Myanmar, and for both cattle and buffalo, and were not significantly different between age groups. Detectable FMDV RNA present on the oral and nasal mucosa of clinically-healthy large ruminants in Laos and Myanmar demonstrates the importance of sampling asymptomatic animals as part of surveillance, and may indicate that subclinical infection plays a role in the epidemiology of FMD in these countries.