Profiling of RNA Viruses in Biting Midges ( Ceratopogonidae ) and Related Diptera from Kenya Using Metagenomics and Metabarcoding Analysis

The majority of the viruses that currently cause diseases in humans and animals are RNA viruses, and more specifically arthropod-transmitted viruses. They cause diseases such as dengue, West Nile infection, bluetongue disease, Schmallenberg disease, and yellow fever, among others.

Overview of Mitigation Programs for Non–EU-Regulated Cattle Diseases in Austria

Background: The non-regulation of animal diseases due to missing regulation at the European Union (EU) level enables member states to implement mitigation programs based on their own country-specific conditions such as priority settings of the governments, availability of financial resources, and epidemiological situation. This can result in a heterogeneous distribution of mitigation activities and prevalence levels within and/or between countries, which can cause difficulties for intracommunity trade. This article aims to describe the past, current, and future mitigation activities and associated prevalence levels for four non-regulated animal diseases, i.e., enzootic bovine leukosis (EBL), infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV), bovine viral diarrhea (BVD), and bluetongue disease (BT) for Austria. Over a period of 40 years (1978–2020), regulations concerning EBL, IBR/IPV, BVD, and BT were retraced to analyze the changes of legislation, focusing on sampling, testing, and mitigation activities in Austria, and were linked to the collected diagnostic testing results. The study results clearly demonstrate the adoption of the legislation by the Austrian governments in dependency of the epidemiological situations. Furthermore, our study shows that, related to the forthcoming Animal Health Law on April 21, 2021, Austria has a good initial situation to achieve disease-free status and/or free from infection status based on the current available epidemiological situation and previously implemented mitigation activities. The study results presented here are intended to contribute to a better comparison of the eradication status across the European countries for non–EU-regulated cattle diseases by providing information about the mitigation activities and data of testing results over a period of 40 years.

Detection of bluetongue virus in Culicoides spp. in southern Yunnan Province, China

Background Culicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses. At least 20 species are considered as vectors or potential vectors of bluetongue virus (BTV) which cause bluetongue disease in ruminants. A BTV prevalence of 30–50% among cattle and goats in tropical southern Yunnan Province, China, prompted an investigation of the potential BTV vectors in this area. Methods Culicoides were collected by light trapping at three sites in the tropical region of Yunnan Province. Species were identified based on morphology and DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in these specimens. Phylogenetic analysis was used to analyze the cox1 sequences of Culicoides specimens infected with BTV. Results Approximately 67,000 specimens of Culicoides were collected, of which 748 were tested for the presence of BTV. Five specimens, including two of Culicoides jacobsoni, one of C. tainanus and two of C. imicola, were identified as infected with BTV. No specimens of C. (subgenus Trithecoides) or C. oxystoma tested were positive for BTV infection. Conclusions To our knowledge this is the first report of C. jacobsoni as a potential BTV vector and the fourth report of an association between C. tainanus and BTV, as well as the first direct evidence of an association between BTV and C. imicola in Asia. A fourth potential cryptic species within C. tainanus was identified in this study. Further analysis is required to confirm the importance of C. jacobsoni and C. tainanus in BTV epidemiology in Asia.

Potential vectors of bluetongue virus in high altitude areas of Yunnan Province, China

Background Bluetongue disease of ruminants is a typical insect-borne disease caused by bluetongue virus (BTV) of the genus Orbivirus (family Reoviridae) and transmitted by some species of Culicoides (Diptera: Ceratopogonidae). Recently, the detection of BTV in yaks in high altitude meadows of the Shangri-La district of Yunnan Province, China, prompted an investigation of the Culicoides fauna as potential vectors of BTV. Methods A total of 806 Culicoides midges were collected by light trapping at three sites at altitudes ranging from 1800 to 3300 m. The species were identified based on morphology and the DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in Culicoides spp. A phylogenetic analysis was used to analyze the cox1 sequences of some specimens. Results Four species dominated these collections and cox1 barcoding revealed that at least two of these appear to belong to species new to science. Culicoides tainanus and a cryptic species morphologically similar to C. tainanus dominated low altitude valley collections while C. nielamensis was the most abundant species in the high-altitude meadow. A species related to C. obsoletus occurred at all altitudes but did not dominate any of the collections. BTV RT-qPCR analysis detected BTV RNA in two specimens of C. tainanus, in one specimen closely related to C. tainanus and in one specimen closely related to C. obsoletus by barcode sequencing. Conclusions This study suggests that BTV in high altitude areas of Yunnan is being transmitted by three species of Culicoides, two of which appear to be new to science. This research may be useful in improving understanding of the effects of global warming on arboviral disease epidemiology and further study is important in research into disease control and prevention.

Presence of Bluetongue Virus Antibodies in Cattle and Sheep in Ogun and Osun States, Nigeria

Bluetongue is an infectious, arthropod-borne viral disease principally affecting ruminants. The occurrence of bluetongue virus (BTV) antibodies in sheep and cattle from backyard farms, cattle markets and abattoirs in Ogun and Osun states of Nigeria was investigated. Three hundred and forty (340) plasma samples comprising 205 from sheep and 135 from cattle were collected from March to September 2017, noting the sex, breed and age of the animals. The samples were screened with a commercial enzyme-linked immunosurbent assay (ELISA) kit that detects BTV antibodies in ruminant plasma or serum. All cattle tested from both states were positive for BTV antibodies giving a seroprevalence of 100% while 95% seroprevalence was obtained for sheep. In Ogun state, prevalence of 90.5% and 98% were obtained for male and female sheep respectively while 95.6% and 95% prevalence were also obtained for male and female sheep respectively in Osun state. Based on breed, 94%, 95%, 95% and 96% prevalence were obtained for Yankasa, Balami, Ouda and West African Dwarf (WAD) sheep respectively in Ogun state while 93%, 95.5%, 100% and 93% prevalence were obtained for Yankasa, Balami, Ouda and WAD sheep respectively in Osun state. Furthermore, prevalence of 92% and 96.7% were obtained for age groups of ≤ 1 year and > 1 year respectively in Ogun state, while prevalence of 96% and 94.7% were obtained for age groups of ≤ 1 year and > 1 year respectively in Osun state. Since vaccination against bluetongue disease is not practiced in Nigeria, the detection of high prevalence of BTV antibodies observed in apparently healthy animals in this study indicates natural, albeit subclinical, infection with the virus and sustained activity of the Culicoides vector. These findings suggest that bluetongue is widespread in southwestern part of Nigeria and highlight the need for continuous surveillance of the disease in the country as well as isolation, identification and characterisation of currently circulating BTV strains in Nigeria.