Complete sequencing of p54-gene from 67 European, American, and West and East African Swine Fever virus (ASFV) isolates revealed that West African and European ASFV isolates classified within the predominant Genotype I according to partial sequencing of p72 were discriminated into four major sub-types on the basis of their p54 sequences. This highlighted the value of p54 gene sequencing as an additional, intermediate-resolution, molecular epidemiological tool for typing of ASFV viruses. We further evaluated p54-based genotyping, in combination with partial sequences of two other genes, for determining the genetic relationships and origin of viruses responsible for disease outbreaks in Kenya. Animals from Western and central Kenya were confirmed as being infected with ASFV using a p72 gene-based PCR assay, following outbreaks of severe hemorrhagic disease in domestic pigs in 2006 and 2007. Eleven hemadsorbing viruses were isolated in macrophage culture and genotyped using a combination of full-length p54-gene sequencing, partial p72-gene sequencing, and analysis of tetrameric amino acid repeat regions within the variable region of the B602L gene (CVR). The data revealed that these isolates were identical in their p72 and p54 sequence to viruses responsible for ASF outbreaks in Uganda in 2003. There was a minor difference in the number of tetrameric repeats within the B602L sequence of the Kenyan isolates that caused the second Kenyan outbreak in 2007. A practical implication of the genetic similarity of the Kenyan and Ugandan viral isolates is that ASF control requires a regional approach.
A frican swine fever (ASF) is a complex and lethal viral disease affecting swine and has a significant socioeconomic impact on both the developed and developing world. It has a major negative effect on national, regional, and international trade and constrains pig production in affected areas. The devastating acute form of the disease is characterized, among other features, by functional and congestive-hemorrhagic disorders of the digestive and respiratory systems and causes around 100% mortality in infected pigs (1). Both European wild boars (Sus scrofa) and feral pigs are susceptible and exhibit clinical signs and mortality rates similar to those of domestic pigs. In contrast, African wild pigs (Phacochoerus and Potamochoerus spp.) are resistant to the disease (2-10).The causative agent of the disease, the ASF virus (ASFV), is a large double-stranded DNA virus and the only member of the Asfarviridae family, genus Asfivirus (11, 12). The virus genome is 170 to 192 kb long (13-17). ASF is endemic in sub-Saharan Africa, where it was first described in 1921 (18). Several outbreaks have occurred since then in Europe and South and Central America. In most non-African countries, the disease has been successfully eradicated, the only exception being Sardinia (Italy), where the disease is still endemic (19,20). In April 2007, the disease spread from East Africa to the Republic of Georgia (21), and outbreaks occurred in Armenia, Azerbaijan, and the Russian Federation (22). The ongoing spread of ASFV into adjacent eastern European countries, such as Ukraine (23,24) and Belarus (25), and the situation in Russia affecting both wild boars and domestic pigs placed neighboring areas in the European Union (EU) at risk for the spread of ASFV. The first cases of ASF in wild boars in Lithuania and Poland were reported in early 2014 in areas bordering . According to the World Organisation for Animal Health (OIE), during 2014, nearly 260 ASF cases or outbreaks in wild boars and domestic pigs were detected in EU countries (Latvia, Lithuania, Estonia, and Poland). This situation, combined with the uncertainty present in Belarus, has created a permanent risk of reintroducing ASF into the EU via wild boars or the illegal trade of contaminated pork products and waste (31).No vaccine is available to prevent ASF infection. The control and eradication measures applicable are based on classical disease control methods, including surveillance, epidemiological investigation, tracing of pigs, and stamping out in infected holdings. Citation Gallardo C, Nieto R, Soler A, Pelayo V, Fernández-Pinero J, MarkowskaDaniel I, Pridotkas G, Nurmoja I, Granta R, Simón A, Pérez C, Martín E, Fernández-Pacheco P, Arias M. 2015. Assessment of African swine fever diagnostic techniques as a response to the epidemic outbreaks in eastern European Union countries: how to improve surveillance and control programs.
The role of the ancestral sylvatic cycle of the African swine fever virus (ASFV) is not well understood in the endemic areas of eastern Africa. We therefore analysed the ASF infection status on samples collected from 51 free-ranging warthogs (Phacocherus africanus) and 1576 Ornithodorus porcinus ticks from 26 independent warthog burrows at a single ranch in Kenya. Abattoir samples from 83 domestic pigs without clinical symptoms, originating from specific locations with no recent reported ASF outbreaks were included in this study. All samples were derived from areas of central Kenya, where ASF outbreaks have been reported in the past. Infection with ASFV was confirmed in 22 % of O. porcinus pools, 3.22 % of adult warthog serum samples and 49 % of domestic pig serum samples by using p72-based PCR. All of the warthog sera were positive for anti-ASFV antibodies, investigated by using ELISA, but none of the domestic pig sera were positive. Twenty O. porcinus-, 12 domestic pig-and three warthogderived viruses were genotyped at four polymorphic loci. The ASFV isolates from ticks and domestic pigs clustered within p72 genotype X. By contrast, ASF viruses genotyped directly from warthog sera, at same locality as the tick isolates, were within p72 genotype IX and genetically similar to viruses causing recent ASF outbreaks in Kenya and Uganda. This represents the first report of the co-existence of different ASFV genotypes in warthog burrow-associated ticks and adult wild warthogs. The data from this and earlier studies suggest transfer of viruses of at least two different p72 genotypes, from wild to domestic pigs in East Africa.
Feed security, feed quality and issues surrounding the safety of raw materials are always of interest to all livestock farmers, feed manufacturers and competent authorities. These concerns are even more important when alternative feed ingredients, new product developments and innovative feeding trends, like insect-meals, are considered. The black soldier fly (Hermetia illucens) is considered a good candidate to be used as feed ingredient for aquaculture and other farm animals, mainly as an alternative protein source. Data on transfer of contaminants from different substrates to the insects, as well as the possible occurrence of toxin-producing fungi in the gut of non-processed insects are very limited. Accordingly, we investigated the impact of the substrate/diet on the intestinal mycobiota of H. illucens larvae using culture-dependent approaches (microbiological analyses, molecular identification through the typing of isolates and the sequencing of the 26S rRNA D1/D2 domain) and amplicon-based next-generation sequencing (454 pyrosequencing). We fed five groups of H. illucens larvae at the third growing stage on two substrates: chicken feed and/or vegetable waste, provided at different timings. The obtained results indicated that Pichia was the most abundant genus associated with the larvae fed on vegetable waste, whereas Trichosporon, Rhodotorula and Geotrichum were the most abundant genera in the larvae fed on chicken feed only. Differences in the fungal communities were highlighted, suggesting that the type of substrate selects diverse yeast and mold genera, in particular vegetable waste is associated with a greater diversity of fungal species compared to chicken feed only. A further confirmation of the significant influence of diet on the mycobiota is the fact that no operational taxonomic unit common to all groups of larvae was detected. Finally, the killer phenotype of isolated yeasts was tested, showing the inhibitory activity of just one species against sensitive strains, out of the 11 tested species.
Restriction enzyme cleavage maps for the fragments produced by Cla I, Sal I and Sma I have been constructed for African swine fever virus (ASFV) DNA grown in pig leukocytes (strain E70 L6) and after adaptation to growth in MS monkey kidney cells (strain E70MS14). The mapping data revealed that before adaptation to growth in MS cells, the size of the DNA from ASFV strain E70 L6 was l73 Kbp and after adaptation it was only l56 Kbp. The decrease in size was produced by deletions and additions mainly in the terminal regions of the genome. These genetic variations were located between 0.0 to 0.01 m.u. (Cla I-M1 fragment), 0.04 to 0.14 m.u. (Sma I-B1, Sal I-A1 fragments), 0.51 to 0.52 m.u. (Cla I-O fragment), 0.84 to 0.86 m.u. (Sma I-H1), 0.95 to 0.97 m.u. (Cla I-A1, Cla I-G1 fragments) and 0.99 to 1.0 m.u. (Cla I-G1) on viral genome of ASFV grown in pig leukocytes.
BackgroundThe Midichloriaceae is a novel family of the order Rickettsiales, that encompasses intracellular bacteria associated with hard ticks (Ixodidae) and other arthropods. The most intensively investigated member of this family is Midichloria mitochondrii, a symbiotic bacterium of the sheep tick Ixodes ricinus, characterized by the capacity of multiplying inside the mitochondria. A recent study suggested that these bacteria might be inoculated into the human host during the tick bite. The purpose of this study was to determine the potential infectivity of Midichloria bacteria for non-human animals exposed to the risk of tick bite.MethodsBlood from horses, cattle, sheep and dogs exposed to the risk of tick bite was included in this study. DNAs were extracted, and amplified using 16S ribosomal RNA primers conserved in the Midichloria genus. Furthermore, sera from dogs exposed to the risk of tick bite were analyzed in order to evaluate the presence of antibodies against the recombinant flagellar protein (rFliD) from M. mitochondrii using an ELISA test.ResultsHere we present two lines of evidence that support the possibility that bacteria from the genus Midichloria are inoculated into vertebrate hosts during a tick bite: (i) a direct evidence, i.e. the detection of circulating DNA from bacteria related with M. mitochondrii, in the blood of vertebrates exposed to tick parasitism; (ii) a further indirect evidence, i.e. the presence of antibodies against an antigen from M. mitochondrii in dogs exposed to the risk of tick bite. It is interesting to note that variability was detected in the Midichloria gene sequences recovered from positive animals, and that some of these sequences were identical to those generated from tick-associated Midichloria.ConclusionsBased on the results, and on the overall information so far published on the genus Midichloria, we suggest that these bacteria are likely to represent a novel group of vector-borne agents, with the potential of infecting mammalian hosts. Whether inoculation of Midichloria bacteria could cause a true infection and pathological alteration in mammalian hosts is still to be determined. Surely, results emphasize the relevance of Midichloria bacteria in investigations on tick immunology and tick-bite markers.
There is still a lack of studies on fungal microbiota in mosquitoes, compared with the number available on bacterial microbiota. This study reports the identification of yeasts of clinical significance in laboratory mosquito species: Anopheles gambiae, Anopheles stephensi, Culex quinquefasciatus, Aedes albopictus and Aedes aegypti. Among the yeasts isolated, they focused on the opportunistic pathogen Candida parapsilosis, since there is a need to better understand breakthrough candidaemia with resistance to the usual antifungals, which requires careful consideration in the broad-spectrum therapy, as documented in many clinical reports. C. parapsilosis occurs widely and has been isolated from diverse sources, including insects, which may contribute to its dissemination. In this study, it was isolated from the gut of An. gambiae and its presence in developmental stages and organs of different mosquito species was studied. Our results indicated that there was a stable association between C. parapsilosis and reared mosquitoes during the entire life cycle, and in adult male and female gut and gonads. A wide occurrence of C. parapsilosis was also documented in several populations of wild mosquitoes. Based on these findings, it can be said that mosquitoes might participate in the spreading of this opportunistic pathogen, not only as a carrier.
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