Foot-and-mouth Disease Serotype Research Articles

Comparative Analysis of Lateral Flow Assay with Indirect ELISA for Detection of Anti-NSP Antibodies of Foot and Mouth Disease

Foot-and-mouth disease (FMD) was an exceedingly infectious disease that spread to Indonesia in May 2022. A reliable diagnostic serologic test that can distinguish between infected and vaccinated animals was an important part of FMD (serotype O) control programs in affected areas in Indonesia. For this reason, a non-structural protein (NSP) serological test based on 3ABC proteins has been used. The indirect ELISA serological test requires time, skill, and specialized equipment. An alternative method that can be employed is the lateral flow assay (LFA), which offers the advantages of simplicity and portability, enabling rapid acquisition of results. The objective of this study was to validate the efficacy of a user-friendly anti-NSP antibody LFA for rapid diagnostic purposes. This was done by assessing its sensitivity and specificity in stored samples that had previously been tested using indirect ELISA. There were 32 preserved biological materials from dairy and beef cattle in three provinces in Indonesia that were examined with developed LFA. The results of each sample on LFA were compared to the ELISA result for its sensitivity and specificity according to positive and negative values on both tests. The test had a sensitivity of 95.2% and a specificity of 100%, compared to the indirect ELISA. The measured kappa value is also very good at 0.93, so LFA can be optionally used when examining anti-NSP FMD antibodies. Therefore, the LFA anti-NSP for detecting FMD is considered reliable because of its simplicity and the accuracy of the test results. Keywords: Antibody, Bovine serum, Foot and mouth disease, Indirect ELISA, Lateral flow assay

Unveiling the spatial distribution and transboundary pathways of FMD serotype O in Western China and its bordering countries.

Foot-and-mouth disease (FMD) is a severe, highly contagious viral disease of livestock that has a significant economic impact on domestic animals and threatens wildlife survival in China and border countries. However, effective surveillance and prevention of this disease is often incomplete and unattainable due to the cost, the great diversity of wildlife hosts, the changing range and dynamics, and the diversity of FMDV. In this study, we used predictive models to reveal the spread and risk of FMD in anticipation of identifying key nodes to control its spread. For the first time, the spatial distribution of FMD serotype O was predicted in western China and border countries using a niche model, which is a combination of eco-geographic, human, topographic, and vegetation variables. The transboundary least-cost pathways (LCPs) model for ungulates in the study area were also calculated. Our study indicates that FMD serotype O survival is seasonal at low altitudes (March and June) and more sensitive to temperature differences at high altitudes. FMD serotype O risk was higher in Central Asian countries and both were highly correlated with the population variables. Ten LCPs were obtained representing Pakistan, Kazakhstan, Kyrgyzstan, and China.

Seroprevalence and Associated Risk Factors of Foot and Mouth Disease in Selected Woredas of the West Omo Zone, Southwest Ethiopia.

Aim and Background: Foot and Mouth Disease (FMD) is a prioritized transboundary animal disease, endemic in Ethiopia, and it has a high impact on cattle production and trade nationally and internationally. Methods: To ascertain the sero-prevalence and identify the exposure factors connected to a seropositive FMD in cattle, a cross-sectional study was conducted in three weredas of the West Omo Zone from January 2022 to February 2022. Multistage sampling was used to take one study wereda based on agroecology from the highland, midland, and lowland of the zone. Selection of cattle herd and blood samples from cattle were taken by using a simple random method. The Statistical Package for Social Science Version 25 was used to analyze the pertinent data once it had been entered and coded into Microsoft Excel. Results: The study area's FMD seroprevalence for individual cattle and at the herd level was 5.3% with a 95% confidence interval (3.51%–7.99%) and 77.78% (n= 9), respectively. The high herd level recorded during the current study was evidence that the disease has spread throughout the zone. Multinomial logistic regression analysis showed the age of the animal and study wereda are significantly(p<0.05) associated with the sero-prevalence of FMD in this study. High cattle movement to big markets and long exposure of old cattle to the disease may contribute to the significant association of the disease with these risk factors. Conclusion: This study showed that herd-level FMD seropositivity is high, necessitating the identification of specific FMD serotypes and the commencement of appropriate FMD prevention and control strategies in the zone.

Compared to Aluminum Hydroxide Adjuvant, Montanide ISA 206 VG Induces a Higher and More Durable Neutralizing Antibody Response against FMDV in Goats.

Foot-and-mouth disease (FMD) has a high prevalence in cloven-hoofed animals. It is also highly contagious and remains a serious threat to livestock worldwide. Despite the widespread vaccination program in Iran, outbreaks of FMD continue to occur. Vaccination is one of the most effective methods of preventing FMD. The vaccines used in Iran are of the inactivated type and contain several serotypes. Since inactivated vaccines without adjuvants do not induce a high and durable antibody response, it is necessary to use adjuvants. Montanide ISA 206 VG is a mineral oil-based adjuvant that produces a water-in-oil-in-water (w:o:w) emulsion in vaccine preparations. However, a large number of manufacturers in Iran and around the world still use alum adjuvant (with or without saponin) to produce the FMD vaccine. This study used Montanide ISA 206 and alum adjuvants to administer the O2010 serotype of the FMD virus to goats. A total of six goats were divided randomly into three groups. Vaccines were administered subcutaneously twice, at a one-month interval. Blood sampling was done at different times, and the micro-neutralization method was used to measure the neutralizing antibody titer in each serum. Seven days after the second vaccination, the alum group's antibody titer was higher but not statistically significant. However, from the 28th day after the second injection until the end of the study, the Montanide ISA 206 group's antibody titer was significantly higher than that of the alum group. Six months after the second injection, the antibody titer in the ISA 206 group remained at the peak level, while in the alum group, it decreased and reached the minimum protective level. Nine months after the second injection, the antibody titer remained at its peak level in the ISA 206 group, whereas it dropped significantly in the alum group. Based on the findings, ISA 206 VG is capable of generating long-term humoral immunity in goats against the FMD serotype O2010 and could replace aluminum hydroxide adjuvants in FMD vaccine preparations.

Bovine Sero- surveillance of Foot- and – Mouth Disease in Four States in Nigeria

Animals with cloven hooves are susceptible to highly contagious foot and mouth disease (FMD). FMD epidemics have affected several underdeveloped countries, including Nigeria. The migration of pastoralist animals has been linked to FMD transmission in Nigeria, and surveillance is essential for assessing the threat and impact of FMD, as well as the emergence of PCP-FMD. Here, we report the sero-surveillance of FMD in cattle in four states in Nigeria in 2019. Sera collected from four states (Anambra, Enugu, Imo, and Katsina) were tested for antibodies against FMD non-structural protein (NSP), with an overall prevalence of 45%. Significantly higher seroprevalence was recorded in Imo (63%), followed by Kastina (56%), Anambra (29%), and Enugu (6%). An overall serotype-specific prevalence of 81%, 35 %, 50 %, and 35% was recorded for serotypes O, A, 50% for SAT 2, and SAT 1, respectively. Furthermore, circulating antibodies against four serotypes of FMDV were found in 16% of sera samples, 20% had antibodies against three circulating serotypes, 33% had antibodies against two serotypes, and 25% showed exposure to only one serotype, indicating exposure to multiple FMD serotypes. These findings demonstrate the presence of FMDV antibodies in cattle across all surveyed states, which may be related to the presence of multiple FMDV serotypes (O, A, SAT1and SAT2) and concurrent co-infection in these states. Therefore, there is a need for the continuous surveillance of FMD in Nigeria. This will help ascertain the burden of the disease and enable the implementation of necessary control measures to stop its potential transmission and further spread. This sero-surveillance data expands our understanding of the FMD situation in Nigeria and is crucial for determining the country’s FMD risk in order to advance the PCP-FMD.

Detection and identification of foot-and-mouth disease O/ME-SA/Ind-2001 virus lineage, Indonesia, 2022

ABSTRACT Foot-and-mouth disease (FMD) is a contagious disease affecting cloven-hoofed animals, which has been well-documented as one of the major animal diseases that causes severe economic loss in livestock sectors. The disease is endemic in many countries, particularly in Asia and Africa. Indonesia has been declared a disease-free country since 1986, and the World Organization of Animal Health (WOAH/OIE) recognized Indonesia as an FMD-free country without vaccination in 1990. However, the FMD virus was detected in many disease outbreaks in cattle and goats in Indonesia in May 2022. This study reports the detection and identification of FMD serotype O viruses in Indonesia. Although these viruses appeared to belong to the ME-SA/Ind-2001e lineage, they formed a unique cluster with 95.3% average nucleotide sequence similarity of the FMD VP1 gene to Ind-2001e viruses from other Asia countries. The illegal trade of live animals from endemic areas in Southeast Asia is one of the possible routes regarding the incursion of FMD in Indonesia, however, it requires further investigation.

Circulating foot-and-mouth disease virus serotype A African-genotype IV in Egypt during 2022.

Foot-and-mouth disease (FMD) virus causes continuous outbreaks, leading to serious economic consequences that affect animal productivity and restrict trade movement. The potential influence of the disease was due to the emergence of new strains or re-emergence of local strains with major antigenic variations due to genetic mutations. This study aims to evaluate circulating virus in samples collected from infected animals during an outbreak using antigenic characterization and identify whether there is an emergence of a new strain or mutation. Reverse-transcription polymerase chain reaction (RT-PCR) was used to screen 86 samples. Viral protein 1 (VP1) codon sequencing was performed. The virus was isolated from the samples inoculated on the baby-hamster kidney cell line and Enzyme-linked immunosorbent assay was performed for serotyping and antigen detection. Based on the RT-PCR screening results, 10 positive samples were selected for sequencing. The sequences belonged to the FMD serotype A African topotype originating from the ancestor prototype Sudan/77, with which it shared 98.48% ± 1.2% similarity. The divergence with local isolates from 2020 was 9.3%. In addition, the sequences were 96.84% ± 1.01% and 95.84% ± 0.79% related to Egyptian-Damietta type 2016 and Sudanese-2018, respectively. Divergence with vaccinal strains ranged from 10% to 17%. Amino acid sequence analysis revealed that the isolates had variation in the most prominent antigenic regions (residues 35-75) and the immunogenic determinants of the G-H loop of VP1 (residues 100-146 and 161-175). The current isolates should be included in the locally produced vaccine to provide broader immunogenic coverage against serotype A African topotypes.

Epidemiological study and dairy farmers’ knowledge, attitudes, and practices on foot and mouth disease in central Ethiopia

Foot and mouth disease (FMD) is consistently ranked as the most economically significant viral disease and one of the top five livestock diseases in Ethiopia. Although FMD is endemic in Ethiopia, the epidemiology and the farmers' knowledge, attitudes, and practices regarding FMD were poorly quantified. Thus, a cross-sectional study was conducted from November 2021 to April 2022 to estimate the seroprevalence, identify the FMD serotypes, and assess the farmers' knowledge, attitudes, and practices on FMD in Addis Ababa city and Sebeta special zone, central Ethiopia. A total of 384 serum samples were collected from cattle and tested using a 3ABC enzyme-linked immunosorbent assay (ELISA). In this study, an overall 56% seroprevalence was recorded. Two types of FMD serotypes were detected in which serotype O was the dominant serotype (75.5%) followed by serotype A (45.5%). A significantly higher seroprevalence (P = 0.00) was recorded in Addis Ababa (85%) compared to Sebeta (28.7%). Seropositivity in older and semi-intensively managed cattle was 2.9 (95% CI: 1.36–6.50; P = 0.006) and 2.1 (95% CI: 1.34–3.26; P = 0.001) times higher compared to young and intensively managed cattle, respectively. A survey on knowledge, attitude, and practice of 103 farmers revealed that 90.2% knew of FMD and the majority of them can recognize its clinical pictures. However, 12.7% of farmers who knew FMD didn't practice any prevention methods. Additionally, 70% of the farmers responded that their cattle roamed outside of their farms for communal grazing, watering, breeding purposes, and vaccination which might put them more at risk of FMD. The current study demonstrated that the majority of farmers have gaps in biosecurity practices and vaccination of cattle against FMD. Therefore, educating farmers on FMD prevention measures is necessary for successful disease control programs.

Foot and Mouth Disease in Adama and Boset districts, East Shewa zone, Ethiopia: Seroprevalence and Virus serotyping

Foot and mouth disease (FMD) is consistently ranked as the most economically important viral disease, and ranks among the top five important livestock diseases in Ethiopia. The status of FMD is barrier for the international trade of livestock and livestock products; thus, continuous epidemiological studies are necessary to develop efficient control strategies. This study determined the seroprevalence of FMD, associated risk factors for its occurrence, and FMD serotypes in the Adama and Boset districts of the East Shewa zone of Oromia Regional State, Ethiopia. A total of 305 blood samples were randomly collected from cattle and subjected to a 3ABC enzyme-linked immune-sorbent assay (ELISA) to detect antibodies against non-structural proteins of FMD virus (FMDV) and Solid-Phase Competitive ELISA for FMDV serotype identification. Evaluation of the associated risk factors was conducted using a multivariable logistic regression model. In this study, an overall seroprevalence of 28.2% (95% CI: 25.7% - 36.2%) was recorded. The risk of being FMD positive was significantly higher in exotic crossbreds [38.60%; OR= 2.23 (95% CI: 1.34 – 3.71); p<0.001] as compared to local breeds. The seroprevalence of FMD was significantly higher in large herd sizes [54.41%; OR=4.2 (95%CI: 3.05 - 15.87), P < 0.001] compared to medium and small herd sizes. Three FMD serotypes namely serotype O, A, and SAT-2 were identified. Besides, mixed serotypes O and A, serotypes O and SAT-2, serotypes A and SAT-2, and serotypes A, O, and SAT-2 were recorded. By considering the detection of multiple serotypes of the FMDV and the lack of cross-protection among the serotypes, the use of polyvalent FMD vaccine against the serotypes of the virus circulating under field conditions is highly recommended.

АНАЛИЗ ЭПИЗООТИЧЕСКОЙ СИТУАЦИИ ПО ЯЩУРУ В РОССИИ С 1991 ПО 2023 ГОДЫ

The spread of foot-and-mouth disease (FMD) in the world has led to the development of a system of regionalisation and the assignment of a status to each country depending on safety and vaccination. FMDfree without vaccination countries export their products around the world. Therefore, it is necessary to strive for the status. To see the true picture of the FMD epizootic situation, the authors analysed the archival materials of Rosselkhoznadzor (the Federal Service for veterinary and Phytosanitary Surveillance) for the period from 1991 to 2023. The research aimed to conduct a retrospective analysis of the FMD epizootic situation in the Russian Federation and determine the prospects for obtaining the status of a “FMD-free without vaccination” country. The study established 96 unsafe points in eleven Russian regions for the analysed period. FMD was most often found in regions that have a land border with China, Mongolia and Kazakhstan. Trans-Baikal Territory is the most FMD affected region, where foot and mouth disease has been recorded eight times over the past thirty years. Primorsky Territory has recorded five FMD outbreaks; four records of FMD were found in Amur Region. A sporadic FMD occurred in Moscow, Vladimir, Orenburg, Khabarovsk and Krasnodar regions, and in the republics of Bashkortostan, Karachay-Cherkessia and Kabardino-Balkaria. The most common FMD serotype is serotype O, which accounts for about 70 % of all outbreaks since 2010. Serotype A was only found in five regions in 2013–2014. The Asia 1 serotype was found once in Vladimir region. Despite the focused effort to obtain the status of “FMD-free without vaccination”, Russia is at high risk of introducing pathogens from border areas. Vaccine refusal may negatively affect the epizootic situation, which has been stable for the past two years. Given the length of the land border, the high risk for FMD in Kazakhstan and the unstable political and economic situation, keeping the country free from FMD is a priority for the Russian Federation.

Epidemiological and clinical characteristics of the foot and mouth disease outbreaks in cattle in central Ethiopia

Foot and mouth disease (FMD) is an acute highly contagious viral disease of all cloven-hoofed animals that causes significant economic problems in Ethiopia. The objectives of this study were to assess the morbidity and clinical features of FMD in sick cattle and identify causal serotypes of FMD outbreaks in central Ethiopia. Outbreaks of FMD were investigated in a total of 150 herds of cattle from January 2021 to April 2021. Seven epithelial tissue and 23 oral swab samples were collected and subjected to a real-time polymerase chain reaction (rRT-PCR) and Sandwich Enzyme-linked Immunosorbent Assay (ELISA) for detection and serotyping of FMD virus, respectively. A total of 150 herds of cattle were examined, of which 114 (76%) herds of cattle were clinically affected with FMD. In this study, 75.9% animal-level morbidity was recorded. Exotic breeds and adult cattle were more affected by Foot and Mouth Disease Virus (FMDV) with morbidity of 100% and 77.4%, respectively. The clinical features in sick cattle showed that profuse salivation was the most frequently observed clinical sign (40%) followed by oral cavity vesicle formation (30%), and interdigital space lesion (15%). Out of 30 samples subjected to rRT-PCR and ELISA test, 28 (93.33%) and 27 (90%) samples were found positive, respectively. In this study, three types of FMD serotypes were detected in which SAT-2 (n = 13) was the predominant serotype followed by serotype O (n = 9), and serotype A (n = 5). The current study revealed that FMD serotype SAT-2 was highly responsible for the occurrence of FMD outbreaks in central Ethiopia. Although the FMD vaccine produced in Ethiopia contains all the identified serotypes, detailed studies on topotypes identification have to be performed to provide full protection.

Foot and mouth disease prevalence in cattle and buffaloes from India determined by systematic review and meta-analysis

In the present study, Foot and Mouth Disease (FMD) prevalence in cattle and buffaloes from India was determined by employing systematic review and meta-analysis. The FMD prevalence studies (73) reported during 1986-2021 were obtained from online databases, offline literatures and meta-analysis by using meta package in R-Software was done. The pooled FMD prevalence in India was 43% (95% level CI 35-52%, PI 3-94%) obtained by using 5,00,267 samples. Period-wise analysis revealed a higher prevalence of 68% during 1986-2000 than recent years. A higher FMD prevalence in east zone (59%), and lower in central zone (24%) was observed. Among 19 states, a higher prevalence of FMD was detected in Rajasthan (81%) and lower in Andaman and Nicobar (3%). Species-wise analysis indicated a higher prevalence in cattle (45%) than buffaloes (30%). The method-wise analysis revealed a higher prevalence in antigen detection (49%) than the antibody detection (42%) methods. The FMD seroprevalence was 59% against the FMD vaccination obtained by liquid phase blocking ELISA. In India, a higher FMD prevalence by serotype O (64%) than other serotypes was observed. Thus, the higher FMD prevalence zone, states, species, methods and serotypes identified may be employed by policy makers for making informed decisions to maximise the use of scarce resources available. There was a decreasing trend in FMD prevalence in the recent years, however, need is there to prevent FMD by vaccination to move in the progressive control pathway stages. This will help in increasing export trade and eventually result in economic benefits to dairy farmers

Emergency FMD Serotype O Vaccines Protect Cattle against Heterologous Challenge with a Variant Foot-and-Mouth Disease Virus from the O/ME-SA/Ind2001 Lineage.

Vaccination is one of the best approaches to control and eradicate foot-and-mouth disease (FMD). To achieve this goal, vaccines with inactivated FMD virus antigen in suitable adjuvants are being used in addition to other control measures. However, only a limited number of vaccine strains are commercially available, which often have a restricted spectrum of activity against the different FMD virus strains in circulation. As a result, when new strains emerge, it is important to measure the efficacy of the current vaccine strains against these new variants. This is important for countries where FMD is endemic but also for countries that hold an FMD vaccine bank, to ensure they are prepared for emergency vaccination. The emergence and spread of the O/ME-SA/Ind-2001 lineage of viruses posed a serious threat to countries with OIE-endorsed FMD control plans who had not reported FMD for many years. In vitro vaccine-matching results showed a poor match (r1-value < 0.3) with the more widely used vaccine strain O1 Manisa and less protection in a challenge test. This paper describes the use of the O3039 vaccine strain as an alternative, either alone or in combination with the O1 Manisa vaccine strain with virulent challenge by a O/ME-SA/Ind-2001d sub-lineage virus from Algeria (O/ALG/3/2014). The experiment included challenge at 7 days post-vaccination (to study protection and emergency use) and 21 days post-vaccination (as in standard potency studies). The results indicated that the O3039 vaccine strain alone, as well as the combination with O1 Manisa, is effective against this strain of the O/ME-SA/Ind/2001d lineage, offering protection from clinical disease even after 7 days post-vaccination with a reduction in viraemia and virus excretion.

Contributions of village animal health workers to foot-and-mouth disease control in Cambodia.

Local animal health services in rural communities in Cambodia are mainly provided by village animal health workers (VAHWs), although the participation and contribution of VAHWs to livestock disease prevention are uncertain. The participation of the VAHWs as identified by their 'dropout rate' was examined in a desktop review in December 2020 of the national data on VAHWs recorded between 2011 and 2020. The contribution and involvement of VAHWs in disease prevention programmes were examined in a survey conducted between February and March 2014, then analyzed in the context of other surveys of VAHW knowledge, attitudes and practices. The survey involved guided group discussion with VAHWs (n=198) from the two Cambodian provinces of Kampong Cham and Pursat. This study identified that VAHWs generated less than 22% of their annual household incomes from animal health services. Less than one-third had vaccinated livestock against foot-and-mouth disease (FMD), with none having vaccinated cattle every 6 months during the study period, and nearly half of the VAHWs having never vaccinated their own cattle against FMD. As no privately provided FMD vaccination services occurred in these communities, with all vaccines delivered through the government-subsidized programme, the findings confirmed that VAHWs only vaccinated animals against FMD when vaccines were made available by the Government. The desktop review found that the number of VAHWs in 2020 declined by more than 24% since 2017, and the proportion of female VAHWs was consistently low, with a mean of 8.26 (±1.019). These findings confirm findings from previous studies that identified considerable weaknesses in the VAHW system in Cambodia, particularly in contributing to FMD control. Cambodian animal health authorities require more effective policies to strengthen the current VAHW system, improving their services delivery; their retention as 'active'; their development of more sustainable roles with lower 'dropout' rates and the prolonged gender inequity. With the limited availability of government-subsidized FMD vaccination currently, extension programmes that engage VAHWs and farmers in seeking privately funded and delivered FMD vaccination that incorporates appropriate multivalent FMD serotype vaccines of high quality, delivered in small dose vials from a robust cold chain, is suggested. This strategy would assist VAHWs to contribute to the provision of private livestock vaccination services that are likely essential for sustainable FMD prevention and control in Cambodia.

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.

Disease surveillance in England and Wales, April 2021

Disease surveillance in England and Wales, April 2021

Spatial distribution and risk areas of foot and mouth disease in mainland China

Foot-and-mouth disease (FMD) is a severe infectious disease in animal, which affects regional economies and food security of many countries. A total of 109 FMD outbreaks in China (from 2010 to 2019) were assessed. To investigate whether the FMD outbreaks were significantly aggregated in China, spatio-temporal cluster analysis was performed. A MaxEnt model was established to identify high risk areas for FMD in China and to identify relevant risk factors. As a result, both the FMD serotype A and O had one cluster each. Roads density, isothermality, UV-B seasonality and railways density were identified as important factors that affect the occurrence of FMD serotype A. The minimum temperature of the coldest month contributed most to FMD serotype O outbreak, followed by railways density and markets distribution. This study may provide useful information for decision makers for the tailoring of a risk-based surveillance of FMD in China.

The risk factor assessment of the spread of foot-and-mouth disease in mainland China

In China, foot-and-mouth disease (FMD) serotype O remains prevalent, and its main host is pigs. Infected but undiscovered pigs can carry foot-and-mouth disease virus (FMDV) for a longtime. And, the virus can spread among farms through pig trade. Although individual vaccination at least 2 times a year and monthly monitoring disease and culling all individual in same group for pigs are adopted vigorously in China, the epidemic remains prevalent. Therefore, in this paper, based on these propagation characteristics and control measures of the epidemic in China, we take the pig farms as research individuals, the trade among farms as transmission routes to establish a dynamic model with nonlinear incidence. In addition, we use this model to assess the impact of trade and transport of pigs among farms on the spread of foot-and-mouth disease virus (FMDV), and to assess the effect of the immunization, monitoring and culling adopted presently in China on the control of the epidemic. By the dynamical analysis of the model, it is found that there will appear backward branching under some conditions, which means that there are two spreading thresholds for the disease, and the disease development trend is also related to the current epidemic situation. Besides, we give the threshold conditions of key parameters to control the spread of FMD. By carrying out data fitting and parameter estimation, we confirm the model rationality, and give four evaluation indexes: the basic reproduction number R0 of FMD serotype O in China, the value of the infected farms at the equilibria, annual probability of a susceptible farm being infected and annual transmission intensity of an infected farm. By carrying out the sensitivity analysis of key parameters on four evaluation indexes, the effect of parameters on the spread of the disease can be intuitively observed. All these can provide a theoretical basis for understanding of the trading-based transmission mechanism, control and prevention of foot-and-mouth disease in pigs in China.

High seroprevalence of Foot and Mouth Disease in Laos: Call for nationwide vaccination campaigns and disease surveillance.

Foot and mouth disease (FMD) virus remains enzootic in Lao People's Democratic Republic (Lao PDR) due to insufficient control measures, including low vaccination coverage. We assessed virus epidemiology and evaluated knowledge, attitude and practice of Lao farmers and animal health stakeholders towards FMD to support politics in devising evidence-based control measures. Sera were collected from 972 domestic ruminants in three provinces of Lao PDR: Vientiane Capital, Vientiane and Xiengkhouang provinces. Seroprevalence of antibodies directed against non-structural proteins of FMD virus was assessed using a commercial ELISA. Positive sera were further characterized by detecting antibodies directed against the structural proteins of FMD serotypes O, A and Asia 1. Information about farm management, biosecurity practices, livestock trade, and past FMD outbreaks was obtained. Overall 35% (340/972) of the ruminants had antibodies against FMD virus with a similar seroprevalence in each province. Seroprevalence depended significantly on the ruminant species (p<.001): 61% of buffaloes, but only 41% of cattle and 15% of goats were seropositive. While antibodies against FMD serotype Asia 1 were absent, 87% (297/340) of the seropositive animals had antibodies against FMD serotype O and 32% (110/340) against FMD serotype A. Many seropositive animals (31%) had antibodies against both serotypes O and A. The majority of the farmers could name the symptoms of FMD and the susceptible animal species. Although many had likely observed FMD outbreaks in their herd and were aware of FMD vaccines, only few vaccinated their animals. This study confirms that FMD remains enzootic in at least three provinces of Lao PDR where vaccination coverage is low. It also shows the relevance of nationwide active and passive disease surveillance, as well as of vaccination campaigns using bivalent FMD vaccines and targeting all susceptible animal species.

Epidemiology and National Surveillance System for Foot and Mouth Disease in Cattle in Thailand during 2008-2019.

Foot and mouth disease (FMD) is a prominent transboundary disease that threatens livestock production and can disrupt the trade in animals and animal products at both regional and international levels. The aims of this study were: (1) to analyze the distribution of FMD in Thailand during the period of 2008 to 2019, (2) to outline a national surveillance approach, and (3) to identify the existing knowledge gap that is associated with this disease in relation to cattle production. We analyzed FMD outbreak data in order to determine the existing spatial and temporal trends and reviewed relevant publications and official documents that helped us outline a national surveillance program. There were 1209 FMD outbreaks in cattle farms during the study period. FMD outbreaks occurred every year throughout the study period in several regions. Notably, FMD serotype O and A were considered the predominant types. The FMD National Strategic Plan (2008–2015) and the national FMD control program (2016–2023) have been implemented in order to control this disease. The surveillance approach employed by livestock authorities included both active and passive surveillance techniques. The vaccination program was applied to herds of cattle 2–3 times per year. Additionally, numerous control measures have been implemented across the country. We have identified the need for a study on the assessment of an applicable surveillance program, the evaluation of an appropriate vaccination strategy and an assessment of the effectiveness of a measured control policy. In conclusion, this study provided much needed knowledge on the epidemiology of FMD outbreaks across Thailand from 2008 to 2019. Additionally, we identified the need for future studies to address the existing knowledge gaps. The findings from this study may also be useful for livestock authorities and stakeholders to establish an enhanced control strategy and to implement an effective surveillance system that would control and eradicate FMD throughout the country.