Economic Aspects of Bovine Ephemeral Fever (BEF) Outbreaks in Dairy Cattle Herds.

Bovine ephemeral fever virus (BEFV) is an arthropod-borne virus (arbovirus) transmitted by blood-feeding insects (mosquitoes and Culicoides biting midges). While the dispersal of arboviral diseases such as bovine ephemeral fever (BEF) into naive areas is often the result of globalization and animal movement, the endemization and local outbreaks of these diseases are mainly influenced by environmental changes. Climate change affects the activity, distribution, dynamics, and life cycles of these vectors (arthropods), the replication of viruses within their vectors, and weakens animal's immune systems. Although BEF does not currently occur in the Americas and Europe (other than in the western regions of Turkey), the risk of BEFV emergence, spread, and endemization in Europe is real. Over the past two decades, arboviruses such as the bluetongue virus (BTV) and Schmallenberg virus (SBV) have emerged in Europe without warning and caused significant losses to the dairy and meat industries. Since the European cattle population has never been exposed to BEFV, the economic losses to dairy and beef production in this continent due to the reduction in milk production, loss of valuable cows, and abortion, should BEF emerge, would probably be considerable. Moreover, arboviruses can also cause substantial financial damage due to restrictions on animal trade and transportation, like the current EHDV-8 outbreak in the Mediterranean basin. In this study, we used national data stored in the Israeli herd book to examine the economic aspects of BEF outbreaks in affected dairy cattle farms countrywide. Our results demonstrate that BEF outbreaks can have immediate and delayed effects, causing severe economic losses due to culling (loss of valuable cows) and a reduction in milk production that affects dairy farm income for months after clinical diagnosis. To our knowledge, this is the first extensive study on the impact of a BEF outbreak at a population level, enabling to conduct accurate risk assessments in future cases of BEFV emergence and re-emergence.

Insights on Transmission, Spread, and Possible Endemization of Selected Arboviruses in Israel-Interim Results from Five-Year Surveillance.

Outbreaks of arthropod-borne (arbo) viruses that infect livestock impact the health and welfare of domestic and wild animals are often responsible for significant economic losses in livestock production. Surveillance and early warning systems effectively predict the emergence and re-emergence of arboviral disease. This paper presents the interim results of five years monitoring the exposure of sentinel naïve heifers and Culicoides biting midges (Diptera; Ceratopogonidae) to bovine ephemeral fever virus (BEFV), Simbu serogroup viruses, bluetongue viruses (BTV), and epizootic hemorrhagic disease viruses (EHDV). The data were collected from 11 dairy farms situated within eight different geographical regions in Israel. The results indicate that cattle in Israel are affected by all four viruses from the early summer onward. The investigated viruses exhibit unique site-specific profiles in both ruminants and vectors. The potential of several vectors to transmit these viruses and lack of cross-protection to re-infection with multiple serotypes (BTV and EHDV) or species (Simbu serogroup viruses) highlights some likely mechanisms that may play a role in these viruses' maintenance cycle and possible endemization in our region.

Pathological and molecular characterisation of peste des petits ruminants in Nubian ibex (Capra nubiana) in Israel.

Peste des petits ruminants (PPR) is a devastating disease that generally affects sheep and goats, mostly in Asia, the Middle East and Africa. The disease has been declared a target for global eradication. Despite its high prevalence in domestic flocks and its high seroprevalence among wildlife, it is rarely reported as a fulminant disease in wild ruminant species (with the exception of Central Asia). In this report, we describe a severe PPR outbreak in a zoo herd of Nubian ibex (Capra nubiana), causing the deaths of 2/3 of the herd. The clinical onset was acute with morbid animals exhibiting lethargy and watery-to-bloody diarrhea and death usually within 48 h. The most consistent gross pathologic findings were hemorrhagic abomasitis and enteritis. Oral lesions and pulmonary lesions were rare. Histology revealed necrohemorrhagic enteritis and abomasitis with myriad nuclear and cytoplasmic viral inclusion bodies. Molecular examinations confirmed the diagnosis of PPR and determined that the causative agent belongs to lineage IV. Further molecular examination showed that the virus belongs to the Asian clade of lineage IV and is closely related to a virus described in Turkey.

Persistence of Lineage IV Peste-des-petits ruminants virus within Israel since 1993: An evolutionary perspective.

Peste-des-petits ruminants (PPR) is one of the most important infectious diseases of domesticated small ruminants. From the initial identification in 1942 in West Africa, PPR virus (PPRV) has spread throughout much of the developing world. PPRV is now considered endemic throughout Africa, with the notable exception of South Africa, the Middle-East and Israel, as well as South-, East-, and Central Asia. Despite this widespread dispersal, the evolution and transmission of PPRV in endemic populations is not well understood. This understanding will be critical in the planning of rational measures to eradicate PPRV by the planned time as defined by the FAO and OIE. To further advance the understanding of the evolution of PPRV the full genome sequence of 18 viruses isolated from Israel from consecutive years between 1997-2014 were generated. This data set is unique and crucial for the understanding of the evolution of PPRV, as it represents the first set of full-length sequence data available from consecutive years from a single geographic location. Analysis of these full genome sequences shows 96.2-99.9% nucleotide conservation across the Israel isolates and further demonstrates the strong purifying selection pressures on PPRV within Israel and globally. Four amino acid substitutions indicative of putative positive selection were additionally identified within the Israel isolates. The mean substitution rate per site per year was estimated to be 9.22 x 10-4 (95% HPD 6.206 x 10-4-1.26 x 10-3). Using Bayesian and phylogenetic analyses we further demonstrate that the PPRV isolates from Israel belongs to linage IV and form a single strong regional cluster within all other lineage IV viruses circulating worldwide implying a single incursion into Israel.

Description of the first acute bovine diarrhea virus-2 outbreak in Israel.

This is the first report of an acute and fatal outbreak of bovine diarrhea virus (BVDV)-2 infection in Israel. The clinical presentation varied with the age of the affected animals with a bovine-respiratory-complex-like syndrome in young stock, and diarrhea and dysentery only in the lactating stock. Enteritis first appeared in one shed of post-parturient cows; it spread for 6 weeks, until at least 30% of the lactating stock contracted enteritis or dysentery. At the same time, dairy calves aged 10-90 days exhibited severe respiratory disease. Of 79 animals that died, 13/350 (3.7%) were adult lactating cows, and 66/1100 (6%) were young feedlot calves. Phylogenetic analysis of the isolated virus revealed a 95% identity with the corresponding genome parts of various BVDV type 2 sequences. The route of introduction of BVDV-2 into Israel could not be elucidated.

Epidemiological investigation of bovine ephemeral Fever outbreaks in Israel.

Outbreaks of bovine ephemeral fever (BEF) occurred in Israel in 1990, 1999, and 2004. The main patterns of BEF spread were similar in the 1990 and in 1999 epidemics, and the BEF virus was probably carried in vectors transported by air streams across the Rift Valley and the Red Sea. In the 2004 outbreak, the primary focus of the disease was the southern Mediterranean coastal plain and the disease agent was apparently brought by infected mosquitoes carried from their breeding site in the Nile Delta by the south-western winds. The disease broke out under optimal ecological conditions, among a vulnerable cattle population and spread rapidly; it showed essentially a spring-summer herd incidence and terminated soon after the night average ambient temperature fell below 16 degrees C in late autumn. The herd incidence of the disease reached 78.4%, 97.7%, and 100% in 1990, 1999, and 2004, respectively. The highest herd incidence, morbidity, and case fatality rates were noted in dairy cattle herds in the Jordan Valley, with morbidity of 20%, 38.6%, and 22.2%, and case fatality rate among affected animals of 2%, 8.6%, and 5.4% in 1990, 1999, and 2004, respectively. The average sero-positivity to BEF in 1999 was 39.5%, which matched the morbidity rate. Comparison among the various age groups showed that the lowest morbidity rates were observed in the youngest age group, that is, heifers up to 1 year, with 3.2%, 3.6%, and 4.2% in 1990, 1999, and 2004, respectively. In heifers from 1 year to calving, the morbidity rates were 13.8%, 14.9%, and 28%, respectively, in first calvers 30.8%, 31.6%, and 28.3%, respectively, and in cows 34.3%, 35.7%, and 27.2%, respectively. All affected cattle were over the age of 3 months. It is hypothesized that mosquitoes and not Culicoides spp. are the vectors of the BEF virus in Israel.

The use of lumpy skin disease virus genome termini for detection and phylogenetic analysis.

During 2006 and 2007 there were two outbreaks of lumpy skin disease (LSD) in Israel. An LSD virus (LSDV)-specific PCR assay was developed that can detected specifically LSDV even though the number of tested LSDV isolates were limited. Full-length sheep pox and LSDV genome sequences were aligned to find non-homologous regions, which were then used for preparing specific primers, whose specificity was tested against several LSDV DNA isolates and the system could detect all the different isolates. Specificity was tested with sheep pox, ORF and other DNA viruses such as bovine herpes 4: the primers did not support amplification of the expected-size fragments, therefore the system appears to be a valuable tool for detecting specifically LSDV. The newly developed system was activated at the first report of a possible disease outbreak. It confirmed the clinical picture, and was introduced subsequently into routine diagnosis. Phylogenetic analyses of a 466-bp fragment next to the genome ends showed that this system can distinguish between: sheep pox, goat pox and LSD, and the results revealed that the Israeli isolates from 2006 and 2007 are in the same clad and essentially identical to Ismaeliya 1989, Nigeria 1996, Senegal 1997, Cameroon 1996, the Kenya NI-2490 isolate, and the South African LD virulent isolate. In contrast the original 1958 LW Neethling vaccine appeared to be in a separate clad, suggesting that the South African attenuated LW vaccine developed from a different ancestral origin that the rest of the viruses tested suggesting that the South African attenuated LW vaccine developed from a different ancestral origin that the rest of the tested viruses or during the process of attenuating the virus by succession of egg inoculations.

Bovine necrotic vulvovaginitis associated with Porphyromonas levii.

An outbreak of bovine necrotic vulvovaginitis associated with Porphyromonas levii, an emerging animal and human pathogen, affected 32 cows on a dairy farm in the northeast of Israel. Five animals had to be culled. This report appears to be the first that associates P. levii with bovine necrotic vulvovagnitis.