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

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.     

Isolation,Characterization and Virulence Potential of Tenacibaculum dicentrarchi in Salmonid Cultures in Chile

In this study, we isolated, identified and characterized isolates of Tenacibaculum dicentrarchi in Atlantic salmon (Salmo salar) farmed in Chile for the first time. In 2010 and 2014, mortalities were observed in Atlantic salmon (average weight 25–30 and 480–520 g, respectively) at an aquaculture centre in Puerto Montt, Chile. Severe tail rots, frayed fins and, in some cases, damaged gills were detected. Wet smear analyses of these lesions revealed a high occurrence of Gram‐negative, filamentous bacteria. Microbiological analysis of infected gill and tail tissues yielded six bacterial isolates. All were identified as T. dicentrarchi through polyphasic taxonomy, which included phenotypic characterization, 16S rRNA sequencing and multilocus sequence typing. The latter method revealed a close relationship of the Chilean genotype with the T. dicentrarchi type strain and two Norwegian Atlantic cod (Gadus morhua) isolates. The pathogenic potential of the TdChD05 isolate was assessed by challenging Atlantic salmon and rainbow trout (Oncorhynchus mykiss) for one hour, which resulted in mean cumulative mortality rates of 65% and 93%, respectively, as well as clinical signs 14 days post‐challenge. However, challenged Coho salmon (Oncorhynchus kisutch) presented no mortalities or clinical signs of infection. These findings indicate that the geographical and host distribution of T. dicentrarchi is wider than previously established and that this bacterium may have negative impacts on salmonid cultures.     

First report on characterization and pathogenicity study of emerging Lactococcus garvieae infection in farmed rainbow trout,Oncorhynchus mykiss (Walbaum), from India

“ Warm water lactococcosis” in farm‐reared rainbow trout, Oncorhynchus mykiss (Walbaum) in the northern Himalayan region of India, caused by bacterium Lactococcus garvieae is described in this study. Nine bacterial isolates were recovered from the organs of haemorrhagic septicaemia rainbow trout and were subjected to biochemical and molecular identification. Cell surface characteristics and virulence of the bacterial isolates are also described. All the nine bacterial isolates had homogenous biochemical characteristics and were Gram‐positive, short chains forming (two to eight cells long), α‐haemolytic, non‐motile ovoid cocci. Partial 16S rDNA nucleotide sequence (~1,400 bp) of current isolates shared 99% identities with the 16S rDNA nucleotide sequence of L. garvieae R421, L. garvieae FMA 395 and L. garvieae CAU :1730. The identity of the bacterial isolates was further confirmed by PCR amplification of L . garvieae‐ specific ~1,100 bp fragment. Transmission electron microscopy (TEM ) of one representative isolate, L. garvieae RTCLI 04, indicates that the isolated strain lacks thick outer capsule and is of KG + (non‐capsulates) phenotype. An intraperitoneal and intramuscular injection (2.6 × 10⁵ CFU ml⁻¹) and also immersion in bacterial suspension @ of 2.6 × 10⁵ CFU ml⁻¹ to healthy rainbow trout juveniles (body weight: 27.5 ± 3.7 g) with L . garvieae RTCLI 04 caused 80%, 60% and 10% cumulative mortality in challenged fish, respectively, within 15 days post‐infection. The haemorrhagic septicaemic disease was reproduced experimentally. Histopathological examination of organs of experimentally infected fish revealed extensive degenerative and inflammatory changes in eye, kidney, gill and liver. PCR amplification of several putative virulence genes such as haemolysins, adhesins, LP xTG ‐containing surface proteins and adhesins cluster confirms the virulence of our Indian L. garvieae isolates. To the best of our knowledge, we are reporting for the first time that L. garvieae is associated with fatal haemorrhagic septicaemia in farmed rainbow trout in India.     

Detection of New Delhi Metallo‐beta‐Lactamase and Extended‐Spectrum beta‐Lactamase Genes in Escherichia coli Isolated from Mastitic Milk Samples

In this study, eight Escherichia coli isolates were obtained from milk samples of dairy cattle suffering from clinical/subclinical mastitis. Isolates were characterized for antimicrobial resistance traits and virulence genes. Results revealed that one isolate was harbouring New Delhi metallo‐beta‐lactamase gene (bla_NDM). Cloning and sequencing of the PCR amplicon confirmed the identity of the gene (GenBank accession no. KC769583 ) having 100% homology with bla_NDM‐5 (GenBank accession no. JN104597.1 ), and this isolate was susceptible to colistin, chloramphenicol and tetracycline only. Moreover, another isolate carried extended‐spectrum beta‐lactamase (ESBL) gene – bla_CTX‐M, and all isolates possessed bla_TEM gene. Of the eight isolates, only one isolate was positive for shiga toxin gene (stx2), and none were harbouring stx1 gene. Occurrence of New Delhi metallo‐beta‐lactamase (bla_NDM) in one E. coli isolate and ESBL genes in other isolates poses a potential threat to human health following possible entry and spread through food chain.     

Development of a non‐lethal hydrogen peroxide treatment for surveillance of Gyrodactylus salaris on trout farms and its application to testing wild salmon populations

This study documents the development of a non‐lethal sampling method to recover gyrodactylid parasites from large numbers of fish that will underpin an improved surveillance strategy for Gyrodactylus salaris. A review of published literature identified over 80 compounds that have previously been tested against gyrodactylids or closely related parasite species. Five safe and relatively fast‐acting compounds were selected for testing to determine their efficiency in removing gyrodactylids from host fish in small‐scale aquaria trials using three‐spined stickleback infected with Gyrodactylus gasterostei as a model host–parasite system. The most effective compound was hydrogen peroxide; short‐duration exposure (3 min) achieved a parasite detection sensitivity of 80%–89%. The practicality of exposing farmed salmonids to hydrogen peroxide for G. salaris surveillance was tested in the field by conducting a parasite recovery trial using a brown trout stock endemically infected with G. truttae and G. derjavinoides and comparing this to the whole‐body examination procedure currently conducted by UK authorities. Significantly more parasites were recovered after exposing fish to hydrogen peroxide and filtering the treatment solution than by direct whole‐body examination of killed fish (mean: 225 vs. 138 parasites per fish). The gyrodactylid recovery rate of the two methods was 84.6% and 51.9%, respectively. A comparison of timings for the two methods indicated scope for significant time savings in adopting the chemical screening method. The study demonstrated that hydrogen peroxide bath treatment may be successfully applied to the surveillance of gyrodactylid parasites and established as a non‐lethal method for sampling farmed and wild fish. This approach has the potential to reduce resources required to collect and isolate parasites for diagnostic testing and improve the sensitivity and confidence of surveillance programmes designed to demonstrate freedom from disease, thus underpinning a robust and defensible surveillance strategy for G. salaris for the UK aquatic animal disease contingency plan.     

Natural infection of a variant pseudorabies virus leads to bovine death in China

Pseudorabies virus (PRV) infects numerous species of domestic and wild animals leading to severe diseases especially in swine and cattle. Since 2011, the variant PRVs were identified in pigs, which were genetically different from classic strains. Although variant PRV infection is widely observed in pigs, there is still no report of variant PRV infection in cattle. Here, we reported a natural infection of variant PRV leading to acute bovine death in Eastern China. Our study suggests that the new variant PRV strains could be a potential threat to cattle industry and possibly to the public health of human.     

Outbreak investigations and molecular characterization of foot‐and‐mouth disease viruses circulating in south‐west Niger

In Niger, the epidemiological situation regarding foot‐and‐mouth disease is unclear as many outbreaks are unreported. This study aimed (i) to identify Foot‐and‐mouth disease virus (FMDV ) strains currently circulating in cattle herds, and (ii) to identify risk factors associated with Foot‐and‐mouth disease (FMD )‐seropositive animals in clinical outbreaks. Epithelial tissues (n  = 25) and sera (n  = 227) were collected from cattle in eight districts of the south‐western part of Niger. Testing of clinical material revealed the presence of FMDV serotype O that was characterized within the O/WEST AFRICA topotype. The antigenic relationship between one of the FMDV isolates from Niger (O/NGR /4/2015) and three reference vaccine strains was determined by the two‐dimensional virus neutralization test (2dmVNT ), revealing a close antigenic match between the field isolate from Niger and three FMDV serotype O vaccine strains. Serological analyses using a non‐structural protein (NSP ) test provided evidence for previous FMDV infection in 70% (158/227) of the sera tested. Multivariate logistic regression analysis revealed that only the herd composition (presence of both cattle and small ruminants) was significantly associated with FMDV seropositivity as defined by NSP ‐positive results (p ‐value = .006). Of these positive sera, subsequent testing by liquid‐phase blocking ELISA (LPBE ) showed that 86% (136/158) were positive for one (or more) of four FMDV serotypes (A, O, Southern African Territories (SAT ) 1 and SAT 2). This study provides epidemiological information about FMD in the south‐western part of Niger and highlights the complex transboundary nature of FMD in Africa. These findings may help to develop effective control and preventive strategies for FMD in Niger as well, as other countries in West Africa.     

Short‐term storage of salmonids semen in a sodium alginate‐based extender

Short‐term storage of semen is a useful strategy for preservation of fish spermatozoa. However, there is a significantly decrease on sperm function mainly due to oxidative stress. In this way, sodium alginate plays an important role as free radical scavenger compound. Accordingly, the aim of our study was to analyse the effect of a sodium alginate‐based extender on sperm function in the short‐term storage of salmonids semen. Samples of Salmo salar, Oncorhynchus kisutch, and Oncorhynchus mykiss were stored in Storfish^® (Ext‐C) and Storfish^® supplemented with sodium alginate (Ext‐A) during 10 days at 4°C. After storage, motility, viability, mitochondrial membrane potential (ΔΨmit), superoxide anion (O₂^?) level and DNA fragmentation (DNA Frag) were assessed. Ext‐A had positive effect in preservation of sperm motility, viability, ΔΨmit, O₂^? level and DNA integrity in the three species analysed compared to control samples. In Ext‐A, the spermatozoa of S. salar and O. mykiss showed significantly higher motility, viability and ΔΨmit than O. kisutch. However, O. kisutch and O. mykiss had significantly lower O₂^? level than S. salar, and DNA fragmentation in O. kisutch and S. salar was significantly lower than in samples of O. mykiss (p < 0.05). Dilution of salmonids semen in a sodium alginate‐based extender is effective for protecting sperm quality during 10 days of short‐term storage.     

Challenges for Serology‐Based Characterization of Foot‐and‐Mouth Disease Outbreaks in Endemic Areas; Identification of Two Separate Lineages of Serotype O FMDV in Uganda in 2011

Control of foot‐and‐mouth disease (FMD) in Uganda by ring vaccination largely depends on costly trivalent vaccines, and use of monovalent vaccines could improve the cost effectiveness. This, however, requires application of highly specific diagnostic tests. This study investigated outbreaks of FMD in seven Ugandan districts, during 2011, using the PrioCHECK^® FMDV NS ELISA, solid‐phase blocking ELISAs (SPBEs) and virus neutralization tests (VNTs), together with virological analyses for characterization of the responsible viruses. Two hundred and eighteen (218) cattle and 23 goat sera as well as 82 oropharyngeal fluid/epithelial tissue samples were collected. Some 50% of the cattle and 17% of the goat sera were positive by the PrioCHECK^® FMDV NS ELISA, while SPBEs identified titres ≥80 for antibodies against serotype O FMD virus (FMDV) in 51% of the anti‐NSP positive cattle sera. However, 35% of the anti‐NSP positive cattle sera had SPBE titres ≥80 against multiple serotypes, primarily against serotypes O, SAT 1 and SAT 3. Comparison of SPBEs and VNTs for the detection of antibodies against serotypes O, SAT 1 and SAT 3 in 72 NSP positive cattle sera showed comparable results against serotype O (P = 0.181), while VNTs detected significantly fewer samples positive for antibodies against SAT 1 and SAT 3 than the SPBEs (P < 0.001). Detection of antibodies against serotype O was consistent with the isolation of serotype O FMDVs from 13 samples. Four of these viruses were sequenced and belonged to two distinct lineages within the East Africa‐2 (EA‐2) topotype, each differing from the currently used vaccine strain (EA‐1 topotype). The relationships of these lineages to other serotype O viruses in the Eastern Africa region are discussed. To enhance the control of FMD in Uganda, there is need to improve the specificity of the SAT‐SPBEs, perform vaccine matching and implement improved regional FMD control.     

Foot‐and‐Mouth Disease in Tanzania from 2001 to 2006

Foot‐and‐mouth disease (FMD) is endemic in Tanzania, with outbreaks occurring almost each year in different parts of the country. There is now a strong political desire to control animal diseases as part of national poverty alleviation strategies. However, FMD control requires improving the current knowledge on the disease dynamics and factors related to FMD occurrence so control measures can be implemented more efficiently. The objectives of this study were to describe the FMD dynamics in Tanzania from 2001 to 2006 and investigate the spatiotemporal patterns of transmission. Extraction maps, the space‐time K‐function and space‐time permutation models based on scan statistics were calculated for each year to evaluate the spatial distribution, the spatiotemporal interaction and the spatiotemporal clustering of FMD‐affected villages. From 2001 to 2006, 878 FMD outbreaks were reported in 605 different villages of 5815 populated places included in the database. The spatial distribution of FMD outbreaks was concentrated along the Tanzania‐Kenya, Tanzania‐Zambia borders, and the Kagera basin bordering Uganda, Rwanda and Tanzania. The spatiotemporal interaction among FMD‐affected villages was statistically significant (P ≤ 0.01) and 12 local spatiotemporal clusters were detected; however, the extent and intensity varied across the study period. Dividing the country in zones according to their epidemiological status will allow improving the control of FMD and delimiting potential FMD‐free areas.     

Investigating Incursions of Bluetongue Virus Using a Model of Long‐Distance Culicoides Biting Midge Dispersal

Bluetongue virus (BTV) is an economically important pathogen of ruminants that is the aetiological agent of the haemorrhagic disease bluetongue. Bluetongue virus is biologically transmitted by Culicoides biting midges (Diptera: Ceratopogonidae), and long‐range dispersal of infected vector species contributes substantially to the rapid spread of the virus. The range of semi‐passive flights of infected Culicoides on prevailing winds has been inferred to reach several hundred kilometres in a single night over water bodies. In this study, an atmospheric dispersion model was parameterized to simulate Culicoides flight activity based on dedicated entomological data sets collected in the UK. Five outbreaks of BTV in Europe were used to evaluate the model for use as an early warning tool and for retrospective analyses of BTV incursions. In each case, the generated predictions were consistent with epidemiological observations confirming its reliability for use in disease outbreak management. Furthermore, the model aided policy makers to predict, contain and eradicate BTV outbreaks in the UK during 2007 and 2008.     

The cost‐effectiveness and budgetary impact of a dolutegravir‐based regimen as first‐line treatment of HIV infection in India

Introduction

Dolutegravir (DTG)‐based antiretroviral therapy (ART) is recommended for first‐line HIV treatment in the US and Europe. Efavirenz (EFV)‐based regimens remain the standard of care (SOC) in India. We examined the clinical and economic impact of DTG‐based first‐line ART in the setting of India's recent guidelines change to treating all patients with HIV infection regardless of CD4 count.

Methods

We used a microsimulation of HIV disease, the Cost‐Effectiveness of Preventing AIDS Complications (CEPAC)‐International model, to project outcomes in ART‐naive patients under two strategies: (1) SOC: EFV/tenofovir disoproxil fumarate (TDF)/lamivudine (3TC); and (2) DTG: DTG + TDF/3TC. Regimen‐specific inputs, including virologic suppression at 48 weeks (SOC: 82% vs. DTG: 90%) and annual costs ($98 vs. $102), were informed by clinical trial data and other sources and varied widely in sensitivity analysis. We compared incremental cost‐effectiveness ratios (ICERs), measured in $/year of life saved (YLS), to India's per capita gross domestic product ($1600 in 2015). We compared the budget impact and HIV transmission effects of the two strategies for the estimated 444,000 and 916,000 patients likely to initiate ART in India over the next 2 and 5 years.

Results

Compared to SOC, DTG improved 5‐year survival from 76.7% to 83.0%, increased life expectancy from 22.0 to 24.8 years (14.0 to 15.5 years, discounted), averted 13,000 transmitted HIV infections over 5 years, increased discounted lifetime care costs from $3040 to $3240, and resulted in a lifetime ICER of $130/YLS, less than 10% of India's per capita GDP in 2015. DTG maintained an ICER below 50% of India's per capita GDP as long as the annual three‐drug regimen cost was ≤$180/year. Over a 2‐ or 5‐year horizon, total undiscounted outlays for HIV‐related care were virtually the same for both strategies.

Conclusions

A generic DTG‐based regimen is likely to be cost‐effective and should be recommended for initial therapy of HIV infection in India.

     

Nationwide Cross‐Sectional Study on Bovine Tuberculosis by Intra Vitam Testing in Germany, 2013–2014

Germany was declared officially free from bovine tuberculosis (bTB) effective from 1 July 1996. After the occurrence of several Mycobacterium (M.) bovis outbreaks in north‐western Germany in recent years with high intraherd prevalence at the time of detection, the reliability of abattoir surveillance as the principal component of the national bTB control programme was debated by veterinary public health officials. Rising numbers of wildlife‐associated outbreaks caused by M. caprae in southern Germany eventually prompted a nationwide cross‐sectional study on bTB. A total of 51 999 cattle, that is 0.41% of the national herd kept on 1.73% of German cattle farms, were tested. Despite 4 positive and 152 inconclusive single intradermal comparative cervical test results, none of the animals was confirmed as bTB‐positive by a subsequent interferon‐release assay or by post‐mortem PCR testing. The estimated prevalence of bTB in Germany was thus calculated as 0.0% (CI 0.0000–0.0064%) affirming that Germany still qualifies as an officially tuberculosis‐free (OTF) country. Occasional randomized nationwide testing can be an appropriate tool to reassure the OTF status and may also help to maintain an appropriate training level for the diagnostic procedures and for supporting sustained disease awareness among stakeholders.     

Foot‐and‐Mouth Disease Virus Serotype O Phylodynamics: Genetic Variability Associated with Epidemiological Factors in Pakistan

One of the most challenging aspects of foot‐and‐mouth disease (FMD) control is the high genetic variability of the FMD virus (FMDV). In endemic settings such as the Indian subcontinent, this variability has resulted in the emergence of pandemic strains that have spread widely and caused devastating outbreaks in disease‐free areas. In countries trying to control and eradicate FMD using vaccination strategies, the constantly evolving and wide diversity of field FMDV strains is an obstacle for identifying vaccine strains that are successful in conferring protection against infection with field viruses. Consequently, quantitative knowledge on the factors that are associated with variability of the FMDV is prerequisite for preventing and controlling FMD in the Indian subcontinent. A hierarchical linear model was used to assess the association between time, space, host species and the genetic variability of serotype O FMDV using viruses collected in Pakistan from 2005 to 2011. Significant (P < 0.05) amino acid and nucleotide variations were associated with spatial distance, but not with differences in host species, which is consistent with the frequent multi‐species infection of this serotype O FMDV. Results from this study will contribute to the understanding of FMDV variability and to the design of FMD control strategies in Pakistan. Viruses sequenced here also provide the earliest reported isolate from the Pan Asia II^ANT‐10 sublineage, which has caused several outbreaks in the Middle East and spread into Europe (Bulgaria) and Africa (Libya).     

Temporospatial Clustering of Foot‐and‐Mouth Disease Outbreaks in Israel and Palestine, 2006–2007

Foot‐and‐mouth disease (FMD) is endemic to the Middle East and there is a perception that political instability and limited resources have led to the uncontrolled circulation of FMD virus throughout the region. Certain aspects of FMD epidemiology in the Middle East remain unknown. The goal of this study was to identify the geographical location, temporal extent and direction of spread of clusters of 70 FMD outbreaks reported in Israel and Palestine from February 4, 2006, through July 15, 2007. The space–time permutation model of the scan statistic test detected nine significant (P < 0.1) clusters. Significant (P < 0.05) direction of spread was identified in four of the nine clusters. The Gaza Strip, where no outbreaks were reported, or a nearby location, seemed to be the origin of a cluster of outbreaks located in Hadarom (April 2007); a cluster of outbreaks centered in West Bank (February 2006) may be linked with spread from Northern Israel; a cluster in Hazafon (January 2007) seemed to have originated from nearby the Jordan borders; and a cluster located in Northern Hazafon was likely related to areas next to the Lebanon and Syrian borders. The association between the clusters in West Bank and earlier Israeli samples and between the cluster in Hazafon and Jordan was also supported (P < 0.05) by phylogenetic analysis of samples collected from the outbreaks. These results suggest that the FMD outbreaks reported in Israel and Palestine in 2006 and 2007 were likely a consequence of different epidemics associated with the circulation and spread of FMD virus strains from different regions of the Middle East.     

Factors affecting Porcine Reproductive and Respiratory Syndrome virus time‐to‐stability in breeding herds in the Midwestern United States

The time needed to wean porcine reproductive and respiratory syndrome (PRRS) virus negative pigs consistently from a breeding herd after an outbreak is referred to as time‐to‐stability (TTS). TTS is an important measure to plan herd closure as well as to manage economic expectations. Weekly PRRS incidence data from 82 sow farms in six production systems located in the Midwestern United States were used for the analysis. The objective of this study was to evaluate the effect of recorded predictors on TTS in participant sow farms. The median TTS was 41.0 weeks (1st quartile 31.0 weeks–3rd quartile 55.0 weeks). In the final multivariable mixed‐effects Cox model, farms that experienced winter (hazard ratio (HR) 2.18, 95% confidence interval (CI) 1.28–3.70) and autumn (HR 1.91, 95% CI 1.16–3.13) PRRS outbreaks achieved stability sooner than farms that experienced PRRS outbreaks during summer. No statistically significant difference (p = 0.76) was observed between the TTS of farms that had a PRRS outbreak during spring and summer (HR 1.09, 95% CI 0.62–1.91). Additionally, farms that had a PRRS outbreak associated with a 1‐7‐4 restriction fragment length polymorphism (RFLP) cut pattern took significantly longer to achieve stability (HR 0.44, 95% CI 0.27–0.72) compared to farms which had a non‐1‐7‐4 PRRS outbreak. Finally, farms that had a previous PRRS outbreak within a year achieved stability sooner (HR 2.18, 95% CI 1.23–3.86) than farms that did not have a previous PRRS outbreak within a year. This study provides information that may result useful for planning herd closure and managing expectations about the time needed to wean PRRS virus negative pigs in breading herds according to the season of the year when the outbreak occurred and the RFLP cut pattern associated with the outbreak virus.     

Incursions of Foot‐and‐Mouth Disease Virus into Europe between 1985 and 2006

Foot‐and‐mouth disease (FMD) is one of the biggest threats to animal health in European countries. In the last 22 years (1985–2006), FMD has occurred 37 times in 14 European countries. Serotype O was most frequently involved in these outbreaks followed by A, C and Asia 1. Sometimes, epidemics were very limited and at other times, they were the cause of devastating economic losses. In most cases (22/37), the origin of the outbreaks could not be determined. For some of these outbreaks, however, routes of introduction and spread were identified through epidemiological inquiries. Moreover, in some cases, the origin of the virus was also traced by phylogenetic analysis of the partial or complete sequences of VP1 genes. Lessons learned from the outbreaks are still useful as most of the same risk factors persist. However, efforts made by FMD‐free countries to help those where the disease is endemic are a valuable strategy for the reduction of the global risk. The present and the future potential sources of FMD infection need to be identified to best focus European efforts.     

Foot‐and‐mouth disease outbreaks in captive scimitar‐horned oryx (Oryx dammah)

This paper describes three episodes of foot‐and‐mouth disease (FMD) that were detected during 2013–2015 in scimitar‐horned oryx (Oryx dammah) (SHO), a large Sahelo‐Saharan antelope extinct in the wild housed in a wild ungulate breeding facility located 50 km east of Abu Dhabi, United Arab Emirates. While no mortality attributable to FMD was noted in the population of nearly 4,000 SHO during two of the three outbreaks, the morbidity varied according to the circulating strains and seroconversion reached a plateau of 78.0% within two weeks and remained at this level for at least nine months. Partial or complete sequencing of the VP1 encoding region demonstrated that the three outbreaks were caused by three different FMDV lineages (O/ME‐SA/PanAsia‐2, A/ASIA/Iran‐05 and O/ME‐SA/Ind‐2001), consistent with FMD viruses that are circulating elsewhere in the region. These findings demonstrate that SHO are susceptible to FMD and highlight the risks of virus incursion into zoos and captive facilities in the Arabian Peninsula.     

Development of a Foot‐and‐Mouth Disease Infection Model in Severe Combined Immunodeficient Mice for the Preliminary Evaluation of Antiviral Drugs

Recent European guidelines facilitate the use of emergency vaccines during outbreaks of foot‐and‐mouth disease. Antiviral drugs could be used as a complementary measure. This study aimed at developing a small animal model to assess the in vivo activity of early antiviral lead molecules with anti‐foot‐and‐mouth disease virus (FMDV) activity in vitro. In a first attempt, several FMDV strains were titrated in Balb/c mice. Inoculations with O₁ Manisa or C₁ Noville did not induce clinical disease, whereas Asia1 Shamir induced death too rapidly [i.e. within 4 days post‐inoculation (dpi)]. Therefore, we switched to severe combined immunodeficient mice which are frequently used as a model for viral infections and experimental therapeutics. Strain O₁ Manisa did not induce clinical disease, but titrations with A₂₂ Iraq, C₁ Noville or Asia1 Shamir resulted in virus‐induced morbidity (including respiratory problems and weight loss) with subsequent mortality. Inoculations with strain A₂₂ Iraq resulted in a reproducible mean time of death of 6 dpi (this was shorter for the other strains). In this newly developed rodent model, strain A₂₂ Iraq seems the most suited to assess the in vivo anti‐FMDV activity of selective inhibitors of FMDV.     

Serum‐free in vitro cultivation of Theileria annulata and Theileria parva schizont‐infected lymphocytes

Theileriosis is a tick‐borne disease caused by intracellular protozoa of the genus Theileria. The most important species in cattle are Theileria annulata and Theileria parva. Both species transform leucocyte host cells, resulting in their uncontrolled proliferation and immortalization. Vaccination with attenuated T. annulata‐infected cell lines is currently the only practical means of inducing immunity in cattle. Culture media for Theileria spp. typically contain 10%–20% foetal bovine serum (FBS). The use of FBS is associated with several disadvantages, such as batch‐to‐batch variation, safety and ethical concerns. In this study, the suitability of serum‐free media for the cultivation of Theileria‐transformed cell lines was examined. Three commercial serum‐free media (HL‐1, ISF‐1 and Hybridomed DIF 1000) were evaluated for their ability to support growth of the T. annulata A288 cell line. The generation doubling times were recorded for each medium and compared with those obtained with conventional FBS‐containing RPMI‐1640 medium. ISF‐1 gave the shortest generation doubling time, averaging 35.4 ± 2.8 hr, significantly shorter than the 52.2 ± 14.9 hr recorded for the conventional medium (p = .0011). ISF‐1 was subsequently tested with additional T. annulata strains. The doubling time of a Moroccan strain was significantly increased (65.4 ± 15.9 hr) compared with the control (47.7 ± 7.5 hr, p = .0004), whereas an Egyptian strain grew significantly faster in ISF‐1 medium (43.4 ± 6.5 hr vs. 89.3 ± 24.8 hr, p = .0001). The latter strain also showed an improved generation doubling time of 73.7 ± 21.9 hr in an animal origin‐free, serum‐free, protein‐free medium (PFHM II) compared with the control. Out of four South African T. parva strains and a Theileria strain isolated from roan antelope (Hippotragus equinus), only one T. parva strain could be propagated in ISF‐1 medium. The use of serum‐free medium may thus be suitable for some Theileria cell cultures and needs to be evaluated on a case‐by‐case basis. The relevance of Theileria cultivation in serum‐free media for applications such as vaccine development requires further examination.