Spread Of Lumpy Skin Disease Research Articles

Comprehensive assessment of lumpy skin disease prevalence across Asia and African countries: A systematic review and meta-analysis

Lumpy Skin Disease (LSD) stands out as one of the economically significant ailments affecting both small-scale farmers and the broader livestock industry. To gauge its prevalence across Asia and Africa, this study employs a rigorous methodology combining systematic review, and meta-analysis, accounting for heterogeneity. Adhering to the guidelines set forth by the cochrane collaboration’s preferred reporting items for systematic reviews and meta-analysis, present initial search sifted through approximately 6,000 articles spanning from 1990 to 2022, using carefully crafted combinations of keywords; Boolean operators, asterisks, and quotation marks. After meticulous assessment for quality bias, employing inclusion and exclusion criteria, 52 publications were included in present study for analysis. The methodology involved in current study utilizing scientometric tools to determine LSD prevalence, with a median sample size of 293 across various studies, predominantly focusing on cattle and buffaloes. Meta-analysis outcomes were dissected based on parameters such as study period, sample size, tests employed, continents, and species, with samples stratified into two to three categories based on medians for heterogeneity assessment. Meta-analysis unveiled a pooled prevalence rate of 14% in Asia and Africa. The subgroup analysis found an 11% prevalence in Asia and Africa constituted 21%. Clinical observation showed a 19% prevalence followed by other tests and PCR with 12 and 13%, respectively. The results underscore the necessity for effective strategies to control and prevent LSD spread, mitigating its economic impact on the livestock industry. This collaborative and comprehensive assessment is crucial in combating the widespread dissemination of LSD and offers valuable insights for policymakers, veterinarians, and stakeholders in the livestock sector.

Space–Time Clustering and Climatic Risk Factors for Lumpy Skin Disease of Cattle in Uttar Pradesh, India, 2022

Lumpy skin disease (LSD), a transboundary infectious disease, negatively impacts cattle health and production. The first LSD outbreaks were reported in India in 2019, and since then, LSD spread to over 15 states, including Uttar Pradesh. This study evaluated LSD cases reported by veterinarians in Uttar Pradesh, India, during 2022. Using scan statistics, Poisson models that accounted for the background cattle population were constructed to identify spatial, temporal, and space–time clusters. A negative binomial regression model was built to assess the impact of temperature and humidity on the incidence rate (IR) of LSD. A total of 112,226 cases across 33 districts were reported in 2022. A purely temporal cluster with higher-than-expected LSD rates was identified between August and October 2022. Several purely spatial clusters were identified in the western part of the state. A primary space–time cluster was detected in west Utter Pradesh between August and October 2022 that overlapped with the spatial clusters. The secondary cluster occurred between September and October 2022 in the eastern part of the state. A rise in humidity (incidence rate ratio (IRR) = 1.39; 95% CI: 1.30–1.49) and temperature (IRR = 1.16; 95% CI: 1.06–1.27) increased the IR of LSD, suggesting a seasonality of the outbreaks. The results of this study can aid animal health authorities in developing effective LSD prevention, surveillance, and control strategies among cattle in India.

Analysis of environmental factors influencing lumpy skin disease outbreak seasonality and assessment of its spread risk in the Saratovskaya oblast of Russia.

Lumpy skin disease (LSD) is a transboundary viral disease of cattle that causes serious economic losses due to a significant decrease in meat and milk productivity. This study analyzed the influence of natural and anthropogenic environmental factors on LSD spread seasonality and assessed the risk of LSD outbreaks in the Saratovskaya oblast of the Russian Federation. Data on LSD outbreaks and environmental factors during different seasons were collected for the period 2011-2020 in the Balkan Peninsula, Middle East, and Russia. Risk assessment was performed using mathematical modeling with generalized linear regression and maximum entropy. Fourteen statistically significant environmental factors influencing LSD spread were identified. The analysis of MaxEnt models built using the selected factors showed that the presence of the pathogen is mostly exerted by: the density of susceptible cattle (an increased risk is observed at a density above 10 and 20 heads/10 km2 in winter and autumn, with a permanent risk in spring and summer), the density of water bodies (the risk is increased at any density in winter and autumn, in the range of 13-23.5 m2/km2 in spring, in the ranges of 0-8 and over 14.5 m2/km2 in summer), and average monthly precipitation rate (the most risky are 105-185 mm/month in winter, 35 mm in spring, 15-105 mm in summer, and above 50 mm in autumn). LSD tends to spread during the warm season. Compared with other test zones, the Saratovskaya oblast has a negligible risk of disease spread (in winter), low risk (in spring), or medium risk (in summer and autumn). The annual risk is low to medium.

OPTIMIZATION OF THE MAIN PARAMETERS OF A LATERAL FLOW ASSAY BASED ON THE RECOMBINANT Р32 ANTIGEN OF LUMPY SKIN DISEASE VIRUS

Lumpy skin disease is a highly contagious infectious transboundary disease of cattle, resulting in significant economic losses. The wide and rapid spread of lumpy skin disease to new territories emphasizes the objective need to improve diagnostic methods. The article outlines the findings of lateral flow assay parameter optimization for lumpy skin disease detection using recombinant P32 antigen. It was found that the optimal amount of protein for immobilization on 20 nm colloidal gold particles was 20 µg/mL. Bovine serum albumin at a final concentration of 0.25% was used to stabilize the conjugate. The optimal dilution of the conjugate was 1:2, and the concentration of recombinant protein and anti-species antibodies for application to the membrane was 500 μg/ml and 250 μg/ml, respectively. The colloidal gold conjugate interacted with antibodies and specifically reacted with the recombinant protein. No cross-reaction with other proteins was noticed at the same time. The created express test allowed for the detection of antibodies from immunized animals when the serum was diluted up to 1:200, however, 1:50 was the ideal ratio. The conjugate remained active after 90 days of storage at room temperature. The findings demonstrate the express method's potential for use in serological research for the prevention and control of the spread of lumpy skin disease.

Effect of thioredoxin on the immunogenicity of the recombinant P32 protein of lumpy skin disease virus.

The rapid spread of lumpy skin disease (LSD) globally poses a serious threat to the agricultural sector. The timely and accurate diagnosis of the disease is crucial to control LSD. This study aimed to determine the effect of thioredoxin on the immunogenicity of the recombinant P32 (rP32) protein of LSD virus (LSDV). Since the P32 protein is poorly soluble, it is often expressed by adding an auxiliary sequence of a highly soluble partner protein such as thioredoxin. The P32 gene fragment was amplified using a polymerase chain reaction from genomic DNA used as a template. The resulting DNA fragments were cloned into the pET32a vector, and transformed into Escherichia coli BL21 (DE3) cells through electroporation. Purification of the rP32 protein was performed using a HisTrap column. Purified rP32 protein fused with thioredoxin (rP32Trx) was characterized by western blotting, liquid chromatography with tandem mass spectrometry and indirect enzyme-linked immunosorbent assay (ELISA). Indirect ELISA revealed that, despite the lower molecular weight, the main part of the antibodies in the serum of immunized mice was directed against thioredoxin and not the target P32 protein. Thus, the antibody titers against rP32Trx were 1:102400, whereas antibody titers against heterologous recombinant 3BTrx and PD1Trx proteins were 1:25600 and 1:51200, respectively. Concurrently, the antibodies did not bind to the heterologous recombinant PD1 protein, which did not contain thioredoxin. The results showed that the rP32 protein fused with the partner protein thioredoxin could not be used to obtain polyclonal and monoclonal antibodies. However, the recombinant fusion protein rP32Trx can be used to develop a serological test to detect antibodies, since antibodies against thioredoxin were not detected in the animal sera.

Applying Different Resampling Strategies In Random Forest Algorithm To Predict Lumpy Skin Disease

The spread of Lumpy Skin Disease (LSD) that infects livestock is increasingly widespread in various parts of the world. Early detection of the disease’s spread is necessary so that the economic losses caused by LSD are not higher. The use of machine learning algorithms to predict the presence of a disease has been carried out, including in the field of animal health. The study aims to predict the presence of LSD in an area by utilizing the LSD dataset obtained from Mendeley Data. The number of lumpy infected cases is so low that it creates imbalanced data, posing a challenge in training machine learning models. Handling the unbalanced data is performed by sampling technique using the Random Under-sampling technique and Synthetic Minority Oversampling Technique (SMOTE). The Random Forest classification model was trained on sample data to predict cases of lumpy infection. The Random Forest classifier performs very well on both under-sampling and oversampling data. Measurement of performance metrics shows that SMOTE has a superior score of 1-2% compared to the use of Random Undersampling. Furthermore, Re-call rate, which is the metric we want to maximize in identifying lumpy cases, is superior when using SMOTE and has slightly better precision than Random Undersampling. This research only focuses on how to balance unbalanced data classes so that the optimization of the model has not been implemented, which creates opportunities for further research in the future.

A highly adaptable platform powered by CRISPR-Cas12a to diagnose lumpy skin disease in cattle

Lumpy skin disease (LSD) in cattle, a transboundary viral disease of cattle once restricted to Africa, has been spreading to many European and Asian countries in the past decade with huge economic losses. This emerging worldwide threat to cattle warrants the development of diagnostic methods for accurate disease screening of suspected samples to effectively control the spread of LSD. In this study, we integrated pre-amplification and three kinds of sensor systems with CRISPR and therefore established an LSD diagnosis platform with highly adaptable and ultra-sensitive advantages. It was the first CRISPR-powered platform that could identify lumpy skin disease virus from vaccine strains of goat pox virus and sheep pox virus. Its limit of detection (LOD) was one copy/reaction after introducing PCR or recombinase-aided amplification (RAA). Moreover, this platform achieved a satisfactory overall agreement in clinical diagnoses of 50 samples and its reproducibility and accuracy were superior to other qPCR methods we tested. The whole diagnostic procedure, from DNA extraction to the results, could complete in 5 h with a total cost of 1.7–9.6 $/test. Overall, this CRISPR-powered platform provided a novel diagnostic tool for portable, ultra-sensitive, rapid, and highly adaptable disease screening of LSD and may be an effective method to control this transboundary disease's spread.

First detection and phylogenetic analysis of lumpy skin disease virus from Kinmen Island, Taiwan in 2020.

Lumpy skin disease is an arthropod-borne bovine disease caused by lumpy skin disease virus. A suspect lumpy skin disease case in a breeding cattle farm on Kinmen Island, Taiwan was reported on July 8, 2020 and later confirmed the first occurrence of lumpy skin disease in the country by molecular biological detections, electron microscopy, and sequence comparison. Implementation of control measures including blanket vaccination on the island effectively ceased the outbreaks. Phylogenetic analyses revealed that the virus discovered in the outbreaks was most similar to those identified in China in 2019. Identifying this virus in the coastal areas in East Asia indicated the rapid eastward spread of lumpy skin disease in Asia.

Emergence and transboundary spread of lumpy skin disease in South Asia

Lumpy skin disease (LSD) is an OIE notifiable, transboundary pox viral disease of livestock. LSD is an emerging disease severely affecting livestock economics. The zoonotic potential of the LSD virus has not been extensively studied and reported. In approximately 90 years, the virus dispersed to numerous world locations after its first emergence in Zambia. LSD virus emergence in South Asia prevailed among livestock (cattle and water buffalo) owners due to economic/financial losses. The estimate of the economic impact of LSD in the southern, eastern and southeastern countries suggested direct losses of livestock and production of approximately USD 1.45 billion. In 2019, nearly the same time, the disease was reported for the first time from many bordering countries, such as India, Nepal, China, and Bangladesh. In 2020, the LSD was also recorded in Bhutan, Sri Lanka, Bangladesh, Vietnam and Southeast China. In 2021, it further spread to new countries such as Thailand, Malaysia and Cambodia. Cattle affected with LSD show a characteristic nodular lesion or skin lump over the whole body and may occasionally be associated with systemic signs. Hematophagous arthropod-borne mechanical transmission is considered primary and the most common route; however, other transmission routes related to illegal animal trade have played a role in the emergence of LSD in countries otherwise/earlier free from it. Among serological diagnostic tests, OIE recommends virus neutralization as the standard gold test. Diagnosis in LSD-free countries requires virus isolation and further sequencing of the isolate. Control of LSD is possible by most of the measures applied for rapidly transmitting viral infection, including vaccination. LSD virus-specific vaccines are considered suitable to confer protection to cattle and buffalo over heterologous vaccines. In countries such as India, the lack of a specific policy for LSD at the time of the first onset of this disease, the high density of susceptible unvaccinated populations, unawareness among farmers, veterinarians and prevailing laws of no slaughter of cattle created a favourable situation of its spread to many states. Amid COVID-19, the whole world is in turmoil; the emergence of diseases such as LSD is further lowering the economy, and hence must be reviewed to save and sustain the backbone of the developing country's economy in Southeast Asia.

Assessment of Maternal Immunity Against LSD in Calves Born to Cows Immunized with Sheep Pox Vaccine at Different Time of Gestation Period

Lumpy skin disease (LSD) is a poxvirus disease of cattle characterized by fever, nodules on the skin, mucous membranes and internal organs, emaciation, enlarged lymph nodes, edema of the skin, and sometimes death. Vaccination of cattle is the most effective option for controlling the spread of lumpy skin disease. All the vaccines used to prevent LSD are currently based on live attenuated viruses. Two types of vaccines against LSD are commercially available; lumpy skin disease vaccine and sheep pox vaccine with the latter is commonly used, but their ability to induce passive immunity is poorly known. Here, we evaluated the passive immunity transferred from dams immunized with sheep pox vaccine to calves. Pregnant cattle were injected with living attenuated sheep pox vaccine Romanian strain via intradermal route. Clinical conditions were monitored throughout the study. The humoral immune response was evaluated in dam and in serum samples collected from newborn calves. The results indicated that sheep pox vaccine vaccines are safe and produce a good humoral immune response in pregnant cattle. Moreover, results showed that, in calf serum, passive immunity persists until three months of age.

Transboundary Spread of Lumpy Skin Disease with Emphasis on Diagnosis and Control

Transboundary Spread of Lumpy Skin Disease with Emphasis on Diagnosis and Control

Entomological and Virological Methods for the Identification of Potential Vectors of Lumpy Skin Disease Virus in the South-Eastern Part of Northern Caucasus, Russia

Abstract The article provides assessment of field and laboratory methods for the collection and evaluation of potential vectors of lumpy skin disease virus (LSDV) in one of the districts of Krasnodarskiy Kray in southern Russia. In this study, we tested several methods of vector collection and a PCR protocol for the detection of the LSDV genome in insects. Descriptive data on samples were collected using a free web-based application Epicollect5. Potential LSDV vectors are quite widely spread insects in this region. We identified 15 insect species, including Musca domestica, Musca autumnalis and Stomoxys calcitrans. Analysis of the insect population showed an increase in species diversity and a decrease in abundance of the insect population by the end of the flight season. PCR tests did not detect LSDV genome in the collected samples. All the methods tested were found suitable for large-scale monitoring of lumpy skin disease (LSD). Further studies on potential risk factors of LSD spread are necessary to improve measures on preventing and eliminating the disease.

The stable fly Stomoxys calcitrans L as a potential vector in the spread of lumpy skin disease virus in Russia: short review

The paper provides literature review on the relationship among climatic conditions, ecological characteristics of the stable fly (Stomoxys calcitrans L.) and the observed spread of lumpy skin disease across the Russian Federation in 2015-2019. This study was carried out to gain an insight into a role of this potential vector in LSDV transmission. Data analysis shows that the flight activity of the stable fly mainly fits into the seasonal pattern of LSD outbreaks. However, there were outbreaks that occurred outside the period of the stable fly flight activity, pointing to other routes of transmission.

Total Number of Cattle in the Republic of Serbia after an Outbreak of Lumpy Skin Disease

Numerous studies conducted worldwide indicate a tendency towards a continuous decline in number of cattle. Appropriate measures should be taken to prevent the reduction of the number of cattle and to increase the concentration of animals per farm. In this regard, the objective of this study was to analyze the total number of cattle after an outbreak of Lumpy Skin Disease (LSD) in the Republic of Serbia. Due to the occurrence of this highly dangerous infectious disease in the Balkans and Eastern Europe, emergency and preventive vaccination was performed in infected and vulnerable areas in the Republic of Serbia. To prevent the spread of LSD, competent authorities banned public gatherings of cattle at fairs, exhibitions, livestock markets and purchase places, which resulted in economic losses for certain farmers. This disease is believed to have impacted the total number of cattle slaughtered and the number of deaths, as well as the import and export of live cattle, animal products and by-products of animal origin. The comparison between indices for the number of cattle shows a decline in the total number of cattle in the analyzed period across statistical territorial units. Results on the total number of cattle can be used, among other things, to create new and more complex questions arising from current and future farming problems.

Epizootic features and control measures for lumpy skin disease in south-east Serbia in 2016.

Lumpy skin disease (LSD) is an infectious disease of cattle caused by virus of the Capripoxvirus genus (LSDV), family Poxviridae. Until 2015, it had not appeared in the Balkans. In June 2016, LSD spread throughout Serbia. This study analyses the first LSD occurrence, epizootic features, applied diagnostic procedures and control measures in five districts in south-east Serbia (Pcinja, Jablanica, Pirot, Toplica and Nisava). In total, there were 225 LSD outbreaks reported in Serbia, out of which 189 (84%) were located in the study area. The highest number of outbreaks was registered in Pcinja district (169), where LSD was first registered. The median distance and time between the nearest previous outbreak sites were calculated (4.32km and 9days). The median altitude of outbreak locations was 992m with more than 90% above 500m (p≤0.001). The average herd morbidity rate in the study area was 13.6% and the herd mortality rate was recorded only in Pcinja (0.5%) and Jablanica (1.6%) districts. Samples taken from the cattle suspected to LSD were subjected to real time PCR analysis. Out of 233 samples tested for LSDV 132 (56.7%) were positive. The LSDV genome was identified in skin nodules (85.4%), blood (72.7%) and nasal swabs (62.5%). Phylogenetic analysis indicated that the LSDV strain circulating in Serbia fell within the cluster of field LSDV found worldwide. In response to the LSD epizootic, animal trade and movement were prohibited, complete stamping out, disinfection, disinsection and an entire bovine population vaccination using the homologous Neethling live attenuated vaccine (OBP, South Africa) were conducted. A month and a half after the completion of the vaccination campaign, the LSD epizootic was stopped, and no new cases have been reported since.

Field observations and experiences gained from the implementation of control measures against lumpy skin disease in South-East Europe between 2015 and 2017

The first epidemics of lumpy skin disease (LSD) reported in Europe in 2015 severely affected the cattle farming sector in several Balkan countries. After the first incursion into Greece in 2015, the disease quickly spread across the Balkan region with over 7000 outbreaks reported by the end of 2016. Thanks to a coordinated regional control and eradication policy, the spread of the disease was halted by the end of 2017. Regional large-scale vaccination campaign with effective homologous vaccines and high vaccination coverage revealed to be essential for the successful control the disease, supported by other measures such as early detection of outbreaks, total or partial stamping out and restrictions on cattle movements. The aim of this paper is to discuss the field observations, challenges and lessons learnt while dealing with the first LSD epidemics in Europe. The cross-border collaboration by the veterinary authorities of all affected countries, coordinated by the European Commission and the technical support provided by many other international organizations played a fundamental role in stopping the spread of a disease that otherwise could have expanded further to the European territory causing a large damage to the whole European cattle farming industry. The experience obtained during the control of LSD epidemics indicates that in the future LSD spread can be effectively halted, provided that appropriate surveillance plans and vigilance remains in place in the areas at risk of re-incursion, especially those bordering endemic countries.

Lumpy skin disease II. Data collection and analysis.

The spatial and temporal patterns of lumpy skin disease (LSD) epidemics were analysed based on the data collected from affected and at‐risk countries in southeastern Europe in 2016 and 2017. The reported outbreaks decreased from 7,483 in 2016 to 385 in 2017. Those were reported mainly in Albania in areas where vaccination was not completed. Only two and four outbreaks were reported in Greece and in the former Yugoslav Republic of Macedonia in 2017, respectively, where the herd immunity achieved by vaccination significantly reduced the further spread of the disease. However, this showed that the virus was still circulating and may re‐emerge in not fully immunised animals. No further outbreaks were reported in the other countries that were affected in 2016, thus providing field evidence about the effectiveness of the regional vaccination campaign. The mathematical model fit to the Albanian data showed that the LSD spread is mostly up to 4 km with some longer distance transmission. The inclusion of relative vector abundance improves the model fit and supports that the abundance of potential LSD vectors is one of the major risk factors for LSD spread. This should be confirmed by field surveys on potential LSD vectors. The vaccination effectiveness in Albania, Bulgaria and Greece was estimated by survival analysis and Cox regression model to be 62%, 96% and 84%, respectively, and these results were validated by the mathematical model. This highlighted that the high coverage vaccination with the live homologous vaccine is the most effective measure for reducing lumpy skin disease virus (LSDV) spread. The housing type of animals was explored as risk factor in Greece, and the risk in farms with outdoor access was six times higher than in farms where animals are kept indoors, independently of vaccination status.

Векторы трансмиссивных вирусных болезней животных

The article reviews the data of Russian and foreign literature sources concerning the spread of vector-born animal infectious diseases such as lumpy skin disease (LSD), Rift Valley fever (RVF), bluetongue. Epidemiology, spread of diseases as well as geographical distribution of their vectors are described, the most probable reasons for expanding the areas of vector-borne infections are considered. Insects and ticks serve not only as vectors, but also as reservoirs and amplifying agents of many pathogens of natural focal infections of human and animals. Of great epidemiological importance is the ability of some vectors to transmit vertically the pathogens from infected females to their offspring. An important role in the epidemiology of vector-borne infections belongs to the following bloodsucking insects - mosquitoes (family Culicidae), sandflies (family Phlebotomidae), midges (family Simuliidae), biting midges (family Heleidae), flies (family Muscidae). Spread of lumpy skin disease to the new territories in recent years is associated with blood-sucking ticks and flying biting insects of the order Diptera (Muscidae -Stomoxys calcitrans; Culicoides - C. Punctatus; Anopheles - An. stephensi; Culex, - Cx. quinquefasciatus). Rift Valley fever virus is transmitted through the bites of infected mosquitoes of the genera Aedes, Anopheles, Coquillettidia, Culex, Eretmopodites Eunelanomyia, Mansonia, Neomelaniconion, Ochlerotatus, Stegomyia. A wide range of mosquitoes’ feeders and the ability of some species to feed consistently on birds and mammals allowed these insects to become the most important vectors of many zoonoses. The major vectors of the bluetongue virus are representatives of blood-sucking biting midges of the genus Culicoides (Diptera: Ceratopogonidae), numbering about 1350 species distributed throughout the world (about 117 species in Europe). This article summarizes data on species composition Culicoides in the world and in the Russian Federation and their competence in the transmission of the bluetongue virus. The major vectors of the bluetongue virus in Africa include representatives of the species C. imicola, in North America - C. sonorensis,.in Australia - C. brevitarsis. In Europe the bluetongue virus is transmitted by biting midges from the complex obsoletus and pulicaris.

Space-time permutation model applied to the past outbreak data of lumpy skin disease in the Balkan Peninsula from august 2015 to july 2017

Introduction: In August 2015, lumpy skin disease (LSD) was notified for the first time in mainland European Union when it was observed in cattle in Greece. From August 2015 to July 2017, 1,757 outbreaks were reported in cattle in Greece, Bulgaria, Macedonia, Albania, Serbia, and Montenegro. Materials and Methods: The Kulldorff space-time permutation scan statistic contained in the software package SaTScan v 9.4.4 was used to analyse the epizootic past outbreak data and describe the spread of the disease in the 24 months after the first notification. Results and Conclusions:: Seventy-six space-time disease clusters (62 significant and 14 non-significant) were identified. In 2015, 10 clusters with a monthly peak in October (n=5, 50%) were identified, in 2016, the most (n=57) clusters were detected with monthly peak in July (n=15, 26.3%), and up to July 2017, nine clusters with a monthly peak in May (n=3, 3.3%) were determined. Possible high-risk areas were identified using the presented methodology, and so this technique could guide national veterinary authorities to formulate strategies for mitigating the spread of LSD, allocating resources and for formulating epidemiological preparedness plans in neighbouring, LSD-negative, countries.

Spread rate of lumpy skin disease in the Balkans, 2015-2016.

After its introduction in Turkey in November 2013 and subsequent spread in this country, lumpy skin disease (LSD) was first reported in the western Turkey in May 2015. It was observed in cattle in Greece and reported to the World Organization for Animal Health (OIE) in August 2015. From May 2015 to August 2016, 1,092 outbreaks of lumpy skin disease were reported in cattle from western Turkey and eight Balkan countries: Greece, Bulgaria, The Former Yugoslav Republic of Macedonia, Serbia, Kosovo, and Albania. During this period, the median LSD spread rate was 7.3km/week. The frequency of outbreaks was highly seasonal, with little or no transmission reported during the winter. Also, the skewed distribution of spread rates suggested two distinct underlying epidemiological processes, associating local and distant spread possibly related to vectors and cattle trade movements, respectively.