Showing papers in "Transboundary and Emerging Diseases in 2015"

Newly Emerged Porcine Deltacoronavirus Associated With Diarrhoea in Swine in China: Identification, Prevalence and Full‐Length Genome Sequence Analysis

Abstract: To identify and characterize aetiologic agent(s) associated with an outbreak of a severe diarrhoea in piglets in Jiangxi, China, in March 2015, a nested reverse transcription-polymerase chain reaction (RT-PCR) for the detection of porcine deltacoronavirus (PDCoV) was developed. A survey based on the nested RT-PCR established indicated that the monoinfection of PDCoV (33.71%) and coinfection of PDCoV (19.66%) with porcine epidemic diarrhoea virus (PEDV) were common in diarrhoeal pigs in Jiangxi, China. A high prevalence of PDCoV (58.33%) in diarrhoeal samples which were PEDV negative was observed. The complete genome sequence of a representative PDCoV strain, PDCoV/CHJXNI2/2015, was determined. Phylogenetic analysis of complete genome and S protein sequences of PDCoV/CHJXNI2/2015 demonstrated that it was most closely related to Hong Kong and US PDCoVs. To our knowledge, this is the first report on the identification, prevalence, complete genome sequencing and molecular characterizations of PDCoV in diarrhoeal samples in pigs in China.

Senecavirus A: An Emerging Vesicular Infection in Brazilian Pig Herds.

Abstract: Summary Vesicular diseases are clinically and economically important infections that affect farm animals. North American studies have suggested that Senecavirus A infection might be associated with a vesicular disease in pigs known as porcine idiopathic vesicular disease (PIVD). In the beginning of 2015, outbreaks of porcine vesicular disease have occurred in six Brazilian states from three geographical regions. Official diagnostic tests were performed with negative results for classical vesicular diseases of compulsory reporting. This study investigated Senecavirus A infection in PIVD outbreaks in which other aetiological agents were ruled out. A primer set was designed to amplify a 542-bp product size of VP3/VP1 region of Senecavirus A genome in RT-PCR assay. Primer specificity was analysed in silico and in porcine biological specimens. For this, clinical specimens were collected from eight pig herds affected with PIVD, including vesicular fluid (n = 4) and swabs (n = 7) and scrapings of ruptured vesicles and ulcerative lesions (n = 5) from weaned and adult pigs. Clinically healthy animals (n = 52) of PIVD-affected and non-affected pig herds also were evaluated for Senecavirus A infection. The 16 samples from PIVD-affected animals were positive for Senecavirus A in the RT-PCR assay, while none of the clinically healthy pigs were detected with the virus. Sequencing analysis revealed high nucleotide (87.6–98.5%) and amino acid (95–99.4%) similarities to SVV-01 prototype and other Senecavirus A strains from North American pigs. Primer set presented herein was suitable for molecular characterization of Senecavirus A. The results suggest that Senecavirus A was the aetiological agent of the vesicular disease outbreaks in the evaluated pig herds. This is the first study to report the Senecavirus A infection in clinically affected pigs outside of North America. Senecavirus A was considered a novel emerging pathogen associated with an important vesicular disease in Brazil.

Identification and Complete Genome of Seneca Valley Virus in Vesicular Fluid and Sera of Pigs Affected with Idiopathic Vesicular Disease, Brazil.

Abstract: Numerous, ongoing outbreaks in Brazilian swine herds have been characterized by vesicular lesions in sows and acute losses of neonatal piglets. The complete genome of Seneca Valley virus (SVV) was identified in vesicular fluid and sera of sows, providing evidence of association between SVV and vesicular disease and viraemia in affected animals.

Assessing the Risk of African Swine Fever Introduction into the European Union by Wild Boar.

Abstract: The presence of African swine fever (ASF) in the Caucasus region and Russian Federation has increased concerns that wild boars may introduce the ASF virus into the European Union (EU). This study describes a semi-quantitative approach for evaluating the risk of ASF introduction into the EU by wild boar movements based on the following risk estimators: the susceptible population of (1) wild boars and (2) domestic pigs in the country of origin; the outbreak density in (3) wild boars and (4) domestic pigs in the countries of origin, the (5) suitable habitat for wild boars along the EU border; and the distance between the EU border and the nearest ASF outbreak in (6) wild boars or (7) domestic pigs. Sensitivity analysis was performed to identify the most influential risk estimators. The highest risk was found to be concentrated in Finland, Romania, Latvia and Poland, and wild boar habitat and outbreak density were the two most important risk estimators. Animal health authorities in at-risk countries should be aware of these risk estimators and should communicate closely with wild boar hunters and pig farmers to rapidly detect and control ASF.

Lumpy Skin Disease in Jordan: Disease Emergence, Clinical Signs, Complications and Preliminary-associated Economic Losses.

Abstract: The objectives of this study are to report the emergence of lumpy skin disease (LSD) in Jordan and associated clinical signs, complications and preliminary economic losses. In mid-April, 2013, two adult dairy cattle developed clinical signs suggestive of LSD and were confirmed as positive by PCR. The two cases were in Bani Kenanah district, Irbid governorate, on the Jordanian border of Israel and Syria. The disease spread rapidly to all the districts of Irbid governorate. During the month following the emergence of the disease, data were collected related to the epidemiology of the disease and the numbers of affected cattle on the premises. Forty-one dairy cattle holdings were surveyed. The morbidity rate ranged from 3% to 100%, (Mean = 35.1%, SD ±28.5%). The mortality rate ranged from 0% to 20%, (Mean = 1.3%, SD ±4.4%). The case fatality rate ranged from 0% to 100%, (Mean = 6.2%, SD ±22%). The overall morbidity rate was 26%, mortality rate 1.9% and case fatality rate 7.5%. Skin nodules, anorexia, decreased milk production and decreased body weight were common clinical signs, while mastitis and myiasis were seen as complications in a few affected animals. Decreased body weight ranged from 0% to 80%, (Mean = 23.1%, SD ±15.7%). Decreased milk production ranged from 0% to 100%, (Mean = 51.5%, SD ±22.2%). Affected cattle were treated mainly with broad-spectrum antibiotics and anti-inflammatory drugs. The cost of treatment ranged from 0 to 84.3 British Pound/animal, (Mean = 27.9 GBP, SD ±22.5 GBP). LSD continues to spread through the Middle East region and poses a serious threat to the rest of Asia and Europe. International collaboration and communication is warranted to prevent the further spread of the disease to the rest of Asia and Europe.

Experimental Transmission of African Swine Fever (ASF) Low Virulent Isolate NH/P68 by Surviving Pigs

Abstract: African swine fever (ASF) has persisted in Eastern Europe since 2007, and two endemic zones have been identified in the central and southern parts of the Russian Federation. Moderate- to low-virulent ASF virus isolates are known to circulate in endemic ASF-affected regions. To improve our knowledge of virus transmission in animals recovered from ASF virus infection, an experimental in vivo study was carried out. Four domestic pigs were inoculated with the NH/P68 ASF virus, previously characterized to develop a chronic form of ASF. Two additional in-contact pigs were introduced at 72 days post-inoculation (dpi) in the same box for virus exposure. The inoculated pigs developed a mild form of the disease, and the virus was isolated from tissues in the inoculated pigs up to 99 dpi (pigs were euthanized at 36, 65, 99 and 134 dpi). In-contact pigs showed mild or no clinical signs, but did become seropositive, and a transient viraemia was detected at 28 days post-exposure (dpe), thereby confirming late virus transmission from the inoculated pigs. Virus transmission to in-contact pigs occurred at four weeks post-exposure, over three months after the primary infection. These results highlight the potential role of survivor pigs in disease maintenance and dissemination in areas where moderate- to low-virulent viruses may be circulating undetected. This study will help design better and more effective control programmes to fight against this disease.

Isolation and genetic characterization of a tembusu virus strain isolated from mosquitoes in Shandong, China

Abstract: Tembusu virus (TMUV) is a flavivirus, presumed to be a mosquito-borne flavivirus of the Ntaya virus subgroup. To date, however, there have been no reports indicating that mosquitoes are involved in the spread of TMUV. In this study, we report the first isolation of TMUV from Culex mosquitoes. We describe the isolation and characterization of a field strain of TMUV from mosquitoes collected in Shandong Province, China. The virus isolate, named TMUV-SDMS, grows well in mosquito cell line C6/36, in Vero and duck embryo fibroblast (DEF) cell lines, and causes significant cytopathic effects in these cell cultures. The TMUV-SDMS genome is a single-stranded RNA, 10 989 nt in length, consisting of a single open reading frame encoding a polyprotein of 3410 amino acids, with 5' and 3' untranslated regions of 142 and 617 nt, respectively. Phylogenetic analysis of the E and NS5 genes revealed that the TMUV-SDMS is closely related to the TMUV YY5 and BYD strains which cause severe egg-drop in ducks. The 3'NTR of TMUV-SDMS contains two pairs of tandem repeat CS and one non-duplicate CS, which have sequence similarities to the same repeats in the YY5 and BYD strains. Our findings indicate that mosquitoes carrying the TMUV may play an important role in the spread of this virus and in disease outbreak.

Lumpy Skin Disease in Iraq: Study of the Disease Emergence

Abstract: This study intends to report the first emergence of lumpy skin disease (LSD) in Iraq, in addition to describing its related clinical signs. In August 2013, 21 cases of four outbreaks developed clinical signs suggestive of LSD in the Nineveh (Mosul) and Baghdad Governorates, which were considered as the first infected foci of LSD in Iraq. The disease was diagnosed tentatively, on the basis of clinical signs and epidemiological features, and it was confirmed as positive by the polymerase chain reaction and histopathological features. In September 2013, eight new outbreaks of LSD also appeared in Baghdad and Nineveh. In 2014, the disease spread rapidly to the governorates of Kirkuk, Salah Al-Din, Al-Anbar, Diyala, Wasit, Babil, Karbala, Najaf, Al-Diwaniyah, Muthanna, Maysan, DhiQar and Basra. The total number of infected cows and calves reported was 7396 and 227, respectively. The apparent morbidity and mortality rates were 9.11% and 0.51%, respectively, while the apparent case-fatality rate was 5.56%. Skin nodules, anorexia, reduce in milk production and decrease in bodyweight were the common clinical signs. Moreover, myiasis and mastitis were seen as complications in some infected animals. Attempts were made to stop the distribution of the disease including quarantine and treatment, control over animal movement and arthropod control. Ring vaccination was used in a 10 km radius zone around the outbreak with live sheep pox vaccine. The highly contagious transboundary nature of the LSD, its endemic distribution in the Iraqi neighbouring countries, and the current armed conflict in the area were the possible factors for the disease being introduced into the country. LSD had spread through the Middle East and Gulf peninsula and could be a cause of danger to the rest of Asia and Europe. International precaution, cooperation and exchange of information could guarantee the prevention and further spread of the disease to the rest of Asia and Europe.

Evidence of transstadial and mechanical transmission of lumpy skin disease virus by Amblyomma hebraeum ticks.

Abstract: Lumpy skin disease (LSD) is an economically important disease caused by LSD virus (LSDV), a Capripoxvirus, characterized by fever and circumscribed skin lesions. It is suspected to be transmitted mechanically by biting flies. To assess the vector potential of Amblyomma hebraeum in transmission of LSDV, mechanical/intrastadial and transstadial modes of transmission of the virus by this tick species were investigated. Two cattle were artificially infected as sources (donors) of infection to ticks. Ticks were infected as either nymphs or adults. Male A. hebraeum ticks were partially fed on donor animals and transferred to recipient animals to test for mechanical/intrastadial transmission. Nymphal A. hebraeum were fed to repletion on donor animals. The emergent adult ticks were placed on recipient animals to test for transstadial transmission of the virus. Successful transmission of LSDV infection was determined in recipient animals by monitoring development of clinical signs, testing of blood for the presence of LSDV by real-time PCR, virus isolation and the serum neutralization test. This report provides further evidence of mechanical/intrastadial and, for the first time, transstadial transmission of LSDV by A. hebraeum. These findings implicate A. hebraeum as a possible maintenance host in the epidemiology of the disease.

Outbreak of Porcine Epidemic Diarrhea Virus in Portugal, 2015

Abstract: An outbreak of porcine epidemic diarrhea virus (PEDV) in the South of Portugal in January 2015 and the spread of PEDV northwards in the territory are described. Comparative analysis of the amplified sequences showed a very high (99.0%) identity with the PEDV variant most recently reported in the United States and also show complete (100%) identity to the strains recently reported in Germany, supporting the hypothesis that a unique strain is currently circulating in Europe. The origin of this PEDV variant still needs to be elucidated and further studies in the remaining European countries may contribute to the knowledge.

Coxiella burnetii (Q-Fever) Seroprevalence in Prey and Predators in the United Kingdom: Evaluation of Infection in Wild Rodents, Foxes and Domestic Cats Using a Modified ELISA

Abstract: Coxiella burnetii, the agent of Q-fever, is recognized as a worldwide zoonosis with a wide host range and potentially complex reservoir systems. Infected ruminants are the main source of infection for humans, but cats and other mammals, including wild rodents, also represent potential sources of infection. There has been a recent upsurge of reported cases in humans, domestic ruminants and wildlife in many parts of the world, and studies have indicated that wild brown rats may act as true reservoirs for C. burnetii and be implicated in outbreaks in livestock and humans. However, investigation of reservoir systems is limited by lack of validated serological tests for wildlife or other non-target species. In this study, serum samples from 796 wild rodents (180 bank voles, 309 field voles, 307 wood mice) 102 wild foxes and 26 domestic cats from three study areas in the UK were tested for the presence of antibodies to C. burnetii using a commercial indirect ELISA kit modified for use in multiple wildlife species. Test thresholds were determined for each species in the absence of species-specific reference sera using a bi-modal latent class mixture model to discriminate between positive from negative results. Based on the thresholds determined, seroprevalence in the wild rodents ranged from 15.6% to 19.1% depending on species (overall 17.3%) and was significantly higher in both foxes (41.2%) and cats (61.5%) than in rodents. This is the first report to quantify seroprevalence to C. burnetii in bank voles, field voles, wood mice, foxes and cats in the UK and provides evidence that predator species could act as indicators for the presence of C. burnetii in rodents. The study demonstrates that wildlife species could be significant reservoirs of infection for both livestock and humans, and the high seroprevalence in domestic cats highlights the potential zoonotic risk from this species.

Carp edema virus/Koi sleepy disease: an emerging disease in Central-East Europe.

Abstract: Koi sleepy disease (KSD), also known as carp edema virus (CEV), was first reported from juvenile colour carp in Japan in the 1970s. Recently, this pox virus was detected in several European countries, including Germany, France and the Netherlands. In England, in addition to colour carp, outbreaks in common carp are reported. KSD/CEV is an emerging infectious disease characterized by a typical sleepy behaviour, enophthalmia, generalized oedematous condition and gill necrosis, leading to hypoxia. High mortality, of up to 80-100%, is seen in juvenile koi collected from infected ponds. In Austria, this disease had not been detected until now. In spring 2014, diagnostic work revealed the disease in two unrelated cases. In one instance, a pond with adult koi was affected; in the other, the disease was diagnosed in adult common carp recently imported from the Czech Republic. A survey was carried out on recent cases (2013/2014), chosen from those with similar anamnestic and physical examination findings, revealing a total of 5/22 cases positive for KSD/CEV. In this study, two paradigmatic cases are presented in detail. Results together with molecular evidence shaped the pattern of the first diagnosis of KSD/CEV in fish from Austrian ponds. In the light of the positive cases detected from archived material, and the spread of the disease through live stock, imported from a neighbouring country, the need for epidemiological investigations in Austria and surrounding countries is emphasized.

SERVAL: a new framework for the evaluation of animal health surveillance.

Abstract: Animal health surveillance programmes may change in response to altering requirements or perceived weaknesses but are seldom subjected to any formal evaluation to ensure that they provide valuable information in an efficient manner. The literature on the evaluation of animal health surveillance systems is sparse, and those that are published may be unstructured and therefore incomplete. To address this gap, we have developed SERVAL, a SuRveillance EVALuation framework, which is novel and aims to be generic and therefore suitable for the evaluation of any animal health surveillance system. The inclusion of socio-economic criteria ensures that economic evaluation is an integral part of this framework. SERVAL was developed with input from a technical workshop of international experts followed by a consultation process involving providers and users of surveillance and evaluation data. It has been applied to a range of case studies encompassing different surveillance and evaluation objectives. Here, we describe the development, structure and application of the SERVAL framework. We discuss users' experiences in applying SERVAL to evaluate animal health surveillance systems in Great Britain.

Hepatitis E virus in wild boar in the central northern part of Italy.

Abstract: Hepatitis E virus (HEV) is responsible for sporadic acute hepatitis in developed countries, where the infection is acquired probably through ingestion of contaminated food, in addition to travel-related cases. In this study, the circulation of HEV in wild boar from nine Italian provinces was evaluated. An overall seroprevalence of 10.2% was found, although there were differences among the provinces, while no samples were positive for HEV RNA detection. This study indicates an active circulation of HEV in the Italian wild boar populations and suggests to consider the zoonotic risk in handling and eating meat from this animal.

Schmallenberg Virus in Culicoides Biting Midges in the Netherlands in 2012.

Abstract: A total of 130 pools of Culicoides biting midges collected between May and September 2012 in the Netherlands were assayed for Schmallenberg virus (SBV). The Culicoides midges were caught in the same area as where in 2011 a high proportion of Culicoides pools tested positive for SBV, in majority with a high viral load (Ct values between 20 and 30). Two of a total of 42 pools comprising 50 midges/pool of the Obsoletus complex from the 2012 collection tested weak positive (Ct values: 34.96 and 37.66), indicating a relatively low viral load. On an individual midge level, the proportion of SBV-infected Culicoides of the Obsoletus complex caught in the same area and in a comparable period of the year was significantly lower in 2012 (0.1% = 1 per 1050 tested) compared with 2011 (0.56% = 13 per 2300 tested).

Emergence and Distribution of Foot-and-Mouth Disease Virus Serotype A and O in Bangladesh.

Abstract: Foot-and-mouth disease (FMD) is endemic in Bangladesh and is predominantly due to FMDV serotype O. In 2012, FMD outbreaks were identified in five different districts of Bangladesh. Of 56 symptomatic cattle epithelial tissue samples, diagnostic PCR assay based on 5'-URT detected 38 FMDV infections. Viral genotyping targeting VP1-encoding region confirmed emergence of two distinct serotypes, A and O with an abundance of serotype A in Chittagong and Gazipur districts and serotype O in Pabna and Faridpur. Only single lineage of both A and O was retrieved from samples of five different regions. Sequencing and phylogenetic analysis of VP1 sequences revealed that serotype O sequences were closely related to the Ind 2001 sublineage of Middle East-South Asia (ME-SA) topotype that was previously circulating in Bangladesh, and serotype A sequences belonging to the genotype VII that was dominant in India during the last decade. The results suggest that extensive cross-border animal movement from neighbouring countries is the most likely source of FMDV serotypes in Bangladesh.

The Cost of Canine Rabies on Four Continents

Abstract: Summary We estimated the economic impacts of canine rabies in Latin America, Africa and Asia. Direct and indirect costs of rabies post-exposure prophylaxis, dog vaccination and control, rabies diagnostic testing and cattle mortality-related costs were accounted for. The number of human deaths was updated from previous estimates based on population growth, and the costs associated with the risk of human mortality were incorporated. We accounted for uncertainty associated with the parameter estimates using a Monte Carlo simulation and estimated that the global burden of canine rabies is approximately $124 billion annually. This result illustrates the potential benefits that could be realized if canine rabies was eliminated and provides an important benchmark against which the cost of any potential elimination campaign can be compared.

Impact of Bovine Herpesvirus 4 (BoHV‐4) on Reproduction

Abstract: Bovine herpesvirus 4 (BoHV-4) is increasingly considered as responsible for various reproductive troubles. This virus infects blood mononuclear cells and displays a specific tropism for vascular endothelia, mammary tissue, endometrium and foetal tissues. Viral multiplication can be reactivated by corticosteroids or stress, both factors present at calving. BoHV-4 has been isolated in a large variety of clinical cases, primarily metritis, vaginitis and mastitis, but also endometritis, abortion and orchitis. Its impact on reproductive performance has been suggested by several epidemiological studies: seroprevalence against BoHV-4 is higher in aborted females and in repeat breeders. Nevertheless, its intrinsic pathogenic power seems low, symptoms developing only when BoHV-4 cooperates with bacteria: within the uterus or mammary gland. BoHV-4 is rather currently considered as a cofactor for the development of an inflammatory reaction initiated by bacteria.

Hepatitis E Virus: First Description in a Pet House Rabbit. A New Transmission Route for Human?

Abstract: In this work, we identified for the first time hepatitis E virus (HEV) in a pet house rabbit, an adult 7 years old female of domestic rabbit (Oryctolagus cuniculus). Importantly, the resulting phylogenetic tree showed that the HEV strain identified in the pet house rabbit was closely related to a human HEV sequence; this finding reawakens concerns regarding the zoonotic risk represented by HEV in animals and expands to house rabbit the spectrum of potential source of infection for humans. Potential for domestic transmission of HEV to humans should be taken into account.

Pseudogymnoascus destructans: evidence of virulent skin invasion for bats under natural conditions, Europe.

Abstract: While Pseudogymnoascus destructans has been responsible for mass bat mortalities from white-nose syndrome (WNS) in North America, its virulence in Europe has been questioned. To shed the light on the issue of host–pathogen interaction between European bats and P. destructans, we examined seventeen bats emerging from the fungus-positive underground hibernacula in the Czech Republic during early spring 2013. Dual wing-membrane biopsies were taken from Barbastella barbastellus (1), Myotis daubentonii (1), Myotis emarginatus (1), Myotis myotis (11), Myotis nattereri (1) and Plecotus auritus (2) for standard histopathology and transmission electron microscopy. Non-lethal collection of suspected WNS lesions was guided by trans-illumination of the wing membranes with ultraviolet light. All bats selected for the present study were PCR-positive for P. destructans and showed microscopic findings consistent with the histopathological criteria for WNS diagnosis. Ultramicroscopy revealed oedema of the connective tissue and derangement of the fibroblasts and elastic fibres associated with skin invasion by P. destructans. Extensive fungal infection induced a marked inflammatory infiltration by neutrophils at the interface between the damaged part of the wing membrane replaced by the fungus and membrane tissue not yet invaded by the pathogen. There was no sign of keratinolytic activity in the stratum corneum. Here, we show that lesions pathognomonic for WNS are common in European bats and may also include overwhelming full-thickness fungal growth through the wing membrane equal in severity to reports from North America. Inter-continental differences in the outcome of WNS in bats in terms of morbidity/mortality may therefore not be due to differences in the pathogen itself.

Rift Valley fever in Kruger National Park: do buffalo play a role in the inter-epidemic circulation of virus?

Abstract: This work was supported in part by a National Science Foundation Ecology of Infectious Diseases Grant (NSF DEB-1102493/EF-0723928 and EF-0723918). Brianna Beechler is supported by a Morris Animal Foundation Fellowship.

Financial Impact of Foot and Mouth Disease on Large Ruminant Smallholder Farmers in the Greater Mekong Subregion

Abstract: Summary A retrospective investigation of financial losses incurred by large ruminant smallholder farmers due to outbreaks of foot and mouth disease (FMD) in 2010–12 in northern Laos was conducted in 2012. The aim was to support recommendations on sustainable transboundary animal disease control strategies in the Greater Mekong Subregion (GMS). Large ruminant smallholders in the three northern provinces of Luang Prabang (LPB), Xiengkhoung (XK) and Xayyabouli (XYL) were interviewed (n = 310). Financial losses were determined, including direct losses due to mortality (100% of pre-FMD sale value) and morbidity (difference between the expected sale price pre-FMD and 1 month following onset of FMD), and indirect losses due to costs of treatments. The losses due to FMD per household varied between provinces (P < 0.001) and were USD 1124, USD 862 and USD 381 in LPB, XK and XYL, respectively, being 60, 40 and 16% of annual household income. Comparison of the costs of FMD with annual household income from sales of large ruminants indicated losses of 213, 181 and 60% of the income in LPB, XK and XYL, respectively. The variation in losses between provinces was due to differences in levels of morbidity with highest in LPB, treatment methods with antibiotic use common in LPB, age of animals sold and sale prices with higher prices in XK. Partial budget analysis of biannual FMD vaccination indicated an average net benefit of USD 22 and USD 33 for cattle and buffalo, respectively. However, vaccination alone is unlikely to control FMD in the region. Promotion of multiple large ruminant health and production intervention programmes to stimulate interest in biosecurity in addition to vaccination is recommended, providing a more sustainable pathway for poverty reduction through the current expansion of livestock investments in the GMS.

Follow-up of the Schmallenberg Virus Seroprevalence in Belgian Cattle.

Abstract: Summary Schmallenberg virus (SBV), which emerged in Northwestern Europe in 2011, is an arthropod-borne virus affecting primarily ruminants. Based on the results of two cross-sectional studies conducted in the Belgian ruminant population during winter 2011–2012, we concluded that at the end of 2011, almost the whole population had already been infected by SBV. A second cross-sectional serological study was conducted in the Belgian cattle population during winter 2012–2013 to examine the situation after the 2012 transmission period and to analyse the change in immunity after 1 year. A total of 7130 blood samples collected between 1st January and 28 February 2013 in 188 herds were tested for the presence of SBV-specific antibodies. All sampled herds tested positive and within-herd seroprevalence was estimated at 65.66% (95% CI: 62.28–69.04). A statistically significant decrease was observed between the beginning and the end of 2012. On the other hand, age-cohort-specific seroprevalence stayed stable from 1 year to the other. During winter 2012–2013, calves between 6 and 12 months had a seroprevalence of 20.59% (95% CI: 15.34–25.83), which seems to be an indication that SBV was still circulating at least in some parts of Belgium during summer–early autumn 2012. Results showed that the level of immunity against SBV of the animals infected has not decreased and remained high after 1 year and that the spread of the virus has slowed down considerably during 2012. This study also indicated that in the coming years, there are likely to be age cohorts of unprotected animals.

Inter-epidemic and between-season persistence of rift valley fever: vertical transmission or cryptic cycling?

Abstract: Rift Valley fever (RVF) is an emerging zoonotic mosquito-borne infectious disease that has been identified as a risk for spread to other continents and can cause mass livestock mortality. In equatorial Africa, outbreaks of RVF are associated with high rainfall, when vector populations are at their highest. It is, however, unclear how RVF virus persists during the inter-epidemic periods and between seasons. Understanding inter-epidemic persistence as well as the role of vectors and hosts is paramount to creating effective management programmes for RVF control. We created a mathematical model for the spread of RVF and used the model to explore different scenarios of persistence including vertical transmission and alternate wildlife hosts, with a case study on buffalo in Kruger National Park, South Africa. Our results suggest that RVF persistence is a delicate balance between numerous species of susceptible hosts, mosquito species, vertical transmission and environmental stochasticity. Further investigations should not focus on a single species, but should instead consider a myriad of susceptible host species when seeking to understand disease dynamics.

Mapping the Serological Prevalence Rate of West Nile fever in Equids, Tunisia

Abstract: West Nile fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in equid sera. However, clinical cases were never reported in equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis.

Improving Smallholder Farmer Biosecurity in the Mekong Region Through Change Management

Abstract: Transboundary animal diseases including foot-and-mouth disease and haemorrhagic septicaemia remain a major constraint for improving smallholder large ruminant productivity in the Mekong region, producing negative impacts on rural livelihoods and compromising efforts to reduce poverty and food insecurity. The traditional husbandry practices of smallholders largely exclude preventive health measures, increasing risks of disease transmission. Although significant efforts have been made to understand the social aspects of change development in agricultural production, attention to improving the adoption of biosecurity has been limited. This study reviews smallholder biosecurity risk factors identified in the peer-reviewed literature and from field research observations conducted in Cambodia and Laos during 2006-2013, considering these in the context of a change management perspective aimed at improving adoption of biosecurity measures. Motivation for change, resistance to change, knowledge management, cultural dimensions, systems theory and leadership are discussed. Due to geographical, physical and resource variability, the implementation of biosecurity interventions suitable for smallholders is not a 'one size fits all'. Smallholders should be educated in biosecurity principles and empowered to make personal decisions rather than adopt prescribed pre-defined interventions. Biosecurity interventions should be aligned with smallholder farmer motivations, preferably offering clear short-term risk management benefits that elicit interest from smallholders. Linking biosecurity and disease control with improved livestock productivity provides opportunities for sustainable improvements in livelihoods. Participatory research and extension that improves farmer knowledge and practices offers a pathway to elicit sustainable broad-scale social change. However, examples of successes need to be communicated both at the 'evidence-based level' to influence regional policy development and at the village or commune level, with 'champion farmers' and 'cross-visits' used to lead local change. The adoption of applied change management principles to improving regional biosecurity may assist current efforts to control and eradicate transboundary diseases in the Mekong region.

Detection of Toxoplasma gondii in the milk of naturally infected goats in the Northeast of Brazil

Abstract: The aim of the present study was to detect the genomic DNA of Toxoplasma gondii in milk samples from naturally infected goats in the state of Pernambuco, (Brazil). In total, 248 blood serum samples were collected and processed from lactating goats and then submitted to a search for antibodies to T. gondii through the indirect immunofluorescence reaction. Samples with a score of 64 or more were considered positive. In total, 248 milk samples were collected and processed from the same group of goats in order to study the DNA of T. gondii using the polymerase chain reaction (PCR) technique. In the serum samples, 56/248 (22.58%) of the animals were positive, whereas the DNA of the parasite was detected in 15/248 (6.05%) of the milk samples. Five of these 15 samples were animals who were also positive in the serology. This study reports the first occurrence of the elimination of T. gondii from the milk of naturally infected goats in the north-east of Brazil. It is suggested that the consumption of in natura goat milk may constitute a potential risk to the health of milk consumers in this region.

Biological Control of Aeromonas salmonicida subsp. salmonicida Infection in Rainbow Trout (Oncorhynchus mykiss) Using Aeromonas Phage PAS‐1

Abstract: Summary The potential control efficacy of Aeromonas phage PAS-1 was evaluated against Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) model in this study. The phage was co-cultured with the virulent A. salmonicida subsp. salmonicida strain AS05 that possesses the type III secretion system (TTSS) ascV gene, and efficient bacteriolytic activity was observed against the bacteria. The administration of PAS-1 in rainbow trout demonstrated that the phage was cleared from the fish within 200 h post-administration, and a temporal neutralizing activity against the phage was detected in the sera of phage-administrated fish. The administration of PAS-1 (multiplicity of infection: 10 000) in A. salmonicida subsp. salmonicida infected rainbow trout model showed notable protective effects, with increased survival rates and mean times to death. These results demonstrated that Aeromonas phage PAS-1 could be considered as an alternative biological control agent against A. salmonicida subsp. salmonicida infections in rainbow trout culture.

A Review of OIE Country Status Recovery Using Vaccinate-to-Live Versus Vaccinate-to-Die Foot-and-Mouth Disease Response Policies II: Waiting Periods After Emergency Vaccination in FMD Free Countries.

Abstract: For countries with OIE status, FMD free country where vaccination is not practised, vaccinate-to-live policies have a significant economic disincentive as the trade restriction waiting period is double that of vaccinate-to-die policies. The disposal of healthy vaccinated animals strictly for the purpose of regaining markets with debatable scientific justification is a global concern. The feasibility of aligning the waiting periods to facilitate vaccinate-to-live is explored. The first article of this two-part review (Barnett et al., 2015) explored the qualities of higher potency Foot-and-Mouth Disease (FMD) vaccines, performance of differentiating infected from vaccinated animals (DIVA) diagnostic assays particularly in vaccinates and carriers, as well as aspects of current limitations of post-outbreak surveillance. Here, the history behind the OIE waiting periods for FMD free status is reviewed as well as whether the risk of vaccinated animals and their subsequent products differ appreciably at 3 versus 6 months. It is concluded that alignment is feasible for vaccinate-to-live using higher potency FMD vaccines within the current OIE waiting period framework of 3 and 6 months blocks of time. These waiting periods reflect precedence, historical practicalities and considered expert opinion rather than a specific scientific rationale. The future lies in updated epidemiological and diagnostic technology to establish an acceptable level of statistical certainty for surveillance or target probability of freedom of FMDV (infection or circulation) not time restricted waiting periods. The OIE Terrestrial Code limits trade from a FMD free country where vaccination is not practiced to animal products and live non-vaccinated animals. The risk of FMDV in products derived from higher potency vaccinated animals is appreciably less than for countries with infected FMD status or even from a FMD free country where vaccination is practised for which the Code has Articles with guidelines for safe trade with time restrictions of 3 months or less. All these presume that key requirements in the implementation of emergency vaccination including appropriate vaccine match, vaccine application, susceptible population coverage, etc. are addressed.

A Review of OIE Country Status Recovery Using Vaccinate-to-Live Versus Vaccinate-to-Die Foot-and-Mouth Disease Response Policies I: Benefits of Higher Potency Vaccines and Associated NSP DIVA Test Systems in Post-Outbreak Surveillance

Abstract: To rapidly return to trade, countries with OIE status, FMD-free country where vaccination is not practised, have destroyed emergency vaccinated animals, raising ethical concerns with respect to social values, the environment, animal welfare and global food security. This two-part review explores whether science could support eligibility to return to previous OIE status in 3 months irrespective of vaccinate-to-live or vaccinate-to-die policies. Here, we examine the benefits of higher potency (≥ 6 PD50 ), high-purity vaccines formulated from antigen banks for emergency use, their efficacy and performance in differentiating infected from vaccinated animals (DIVA) assays for post-outbreak surveillance. From an intensive programme of research, we conclude that high-quality, higher potency vaccines are proven to reduce FMD virus (FMDV) subclinical circulation and the risk of carriers. Broader coverage than predicted by serology suggests the potential to hold a few 'key' vaccine strains improving logistics and reducing the financial burden of antigen banks. The OIE should adopt formal definitions for emergency vaccination and emergency vaccines. In terms of supportive tools, we consider that the lack of OIE recognition of DIVA tests other than those of PANAFTOSA in cattle is a shortcoming. There is need for research on maternal antibody interference with DIVA tests and on the use of such tests to establish whether greater purification of vaccines improves performance. We consider that alignment of waiting periods for vaccinate-to-live and vaccinate-to-die in OIE Code Article 8.5.9 1 b. and c. is feasible until an acceptable level of statistical certainty for surveillance or target probability of freedom is established to substantiate the absence of FMDV infection or circulation. It is surveillance intensity rather than waiting periods that establishes the risk of residual FMDV. EU Directive 2003/85/EC implicitly recognizes this, permitting derogation of the OIE waiting periods.