Genetic characterization of African swine fever virus in Cameroon, 2010–2018

Wade, Abel; Achenbach, Jenna E.; Gallardo, Carmina; Settypalli, Tirumala Bharani Kumar; Abdoulkadiri, Souley; Djonwe, Gaston; Loitsch, Angelika; Dauphin, Gwenae͏̈lle; Ngang, Jean Justin Essia; Boyomo, Onana; Cattoli, Giovanni; Diallo, Adama; Lamien, Charles Euloge

doi:10.1007/s12275-019-8457-4

Cited by 35 publications

(50 citation statements)

References 27 publications

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“…These data suggest that there is a predominant variant causing the outbreaks in Estonia, as no significant genetic changes have occurred in the regions evaluated over the five-year period. Although analysis of the CVR has been widely used to distinguish between closely related ASF isolates in Africa [27,28] and Europe [29], the low CVR genetic variability necessitates further research into alternative and more informative gene regions to clarify the relevant intra genotype relationships. Recent studies on the molecular evolution of genotype II EU strains revealed the presence of five different variants circulating in the EU when sequencing the IGR between the MGF505 9R and 10R genes [Gallardo personal communication 2019].…”

Section: Discussionmentioning

confidence: 99%

“…Although the partial p72 sequencing has proved useful for placing the viruses within one of the defined 24 genotypes, a higher resolution is needed for an in-depth analysis. Several studies have described the suitability of the sequencing of tandem repeat sequences (TRSs) located in the central variable region (CVR) within the B602L-gene to distinguish between closely related ASF isolates belonging to a single genotype [17,[26][27][28]. Until this study only one CVR variant (GII-CVR1, the "Georgia type variant") was described in ASFV genotype II, characterized by the 10 amino acid TRS [23,29] Nevertheless, this region was selected for a deeper molecular characterization of the selected Estonian ASFV isolates collected since September 2014, when the first case of ASF was diagnosed in a wild boar found dead in southern Estonia near the Latvian border.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Characterization of African Swine Fever Virus Isolates in Estonia in 2014–2019

et al. 2020

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After the extensive spread of the African swine fever virus (ASFV) genotype II in Eastern Europe, the first case of African swine fever (ASF) in Estonia was diagnosed in September 2014. By the end of 2019, 3971 ASFV-positive wild boars were found, and 27 domestic pig outbreaks were reported. A selection of ASFV isolates from wild boar and domestic pigs (during the period of September 2014–2019) was molecularly characterized using standardized genotyping procedures. One of the proven markers to characterize this virus is the central variable region (CVR) within the B602L gene. In summer 2015, a new ASFV genotype II CVR variant 2 (GII-CVR2) was confirmed in Estonia. The results suggest that the GII-CVR2 variant was only confirmed in wild boar from a limited area in southern Estonia in 2015 and 2016. In addition to GII-CVR2, a single nucleotide polymorphism (SNP) that resulted in amino acid change was identified within the genotype II CVR variant 1 (GII-CVR1). The GII-CVR1/SNP1 strain was isolated in Estonia in November 2016. Additional GII-CVR1/SNP1 cases were confirmed in two neighbouring counties, as well as in one outbreak farm in June 2017. Based on the available data, no GII-CVR2 and GII-CVR1/SNP1 have been reported by other affected European countries. The spread of variant strains in Estonia has been limited over time, and restricted to a relatively small area.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular Characterization of African Swine Fever Virus Isolates in Estonia in 2014–2019

et al. 2020

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“…The laboratory analyses were twofold: screening for antibodies against the ASF virus in pig serum was carried out using the IDvet ASF indirect ELISA kit (IDvet, Grabels, FRANCE) according to the manufacturer’s instructions; RT-PCR diagnosis was performed on the whole blood, kidney, spleen, lungs, lymph nodes, and liver, following the methodology employed by King et al [ 15 ] partially modified by Wade et al [ 16 ]. Briefly, 2 μL of DNA was added into a 20 μL PCR mix containing 1 × iQ Supermix (Bio-Rad), 400 nM of each primer (King-s 5-CTGCTCATGGTATCAATCTTATCGA-3Gand King-a 5-GATACCACAAGATCRGCCGT-3) and 250 nM of probe (FAM-CCACGGGAGGAATACCAACCCAGTG- TAMRA).…”

Section: Methodsmentioning

confidence: 99%

Epidemiology of African Swine Fever in Piggeries in the Center, South and South-West of Cameroon

Ngwa

Abouna

Zoli

et al. 2020

Veterinary Sciences

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African Swine Fever (ASF) is enzootic in Cameroon. A cross-sectional study was conducted in the center, south and south-west regions of Cameroon in order to determine: the knowledge, skills and practices at risk of pig breeders; the prevalence of the disease in piggeries; the genome of the circulating virus. A total of 684 blood samples were collected in 209 farms for RT-PCR and ELISA analyses at the National Veterinary Laboratory (LANAVET) annex in Yaoundé. Prevalences of 15.2% (95CI: 12.5–17.9%) by ELISA, 23.8% (95CI: 20.6–27.0%) by RT-PCR, and 15.2% (95CI: 12.5–17.9%) by ELISA-PCR, were recorded. Of the farmers surveyed, 90% knew about the ASF and 55.3% have already experienced it. The 47.4% of them would not be able to recognize ASF if it occurred and, according to them, the risk of the disease introduction in farms would be 32% linked to the animal health personnel who work on farms. Molecular characterization revealed that only ASF genotype-I variable 19T-RSs is circulating. ASF is still hovering at a risky rate over the pig sector of Cameroon. The control of ASF needs an epidemiological surveillance, a better involvement of all stakeholders, sensitization of breeders and an effective State support for producers.

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“…Brie y, in West Africa, where there is no evidence of the existence of the ASFV sylvatic cycle, only genotype I has been reported. In Central, Eastern and Southern Africa where three ASFV transmission cycles exist, rich ASFV genotypic variability exists with all 24 (I to XXIV) ASFV genotypes (9,13,(22)(23)(24)(25). In Malawi, ASF is endemic and several outbreaks have been reported to the World Organization for Animal Health (OIE) in almost all its provinces (9,10,22,26).…”

Section: Introductionmentioning

confidence: 99%

Genetic profile of African swine fever virus responsible for the 2019 outbreak in northern Malawi

Hakizimana

Kamwendo

Chulu

et al. 2020

Preprint

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Background: African swine fever (ASF) is an infectious transboundary animal disease which causes high mortality, approaching 100% in domestic pigs and it is currently considered as the most serious constraint to domestic pig industry and food security globally. Despite regular ASF outbreaks within Malawi, few studies have genetically characterized the causative ASF virus (ASFV). This study aimed at genetic characterization of ASFV responsible for the 2019 outbreak in northern Malawi. The disease confirmation was done by polymerase chain reaction (PCR) followed by molecular characterization of the causative ASFV by partial genome sequencing and phylogenetic reconstruction of the B646L (p72) gene, nucleotide alignment of the intergenic region (IGR) between I73R and I329L genes and translation of the central variable region (CVR) coded by B602L gene.Results: All thirteen samples collected during this study in Karonga district in September 2019 were ASFV-positive and after partial genome sequencing and phylogenetic reconstruction of the B646L (p72) gene, the viruses clustered into ASFV p72 genotype II. The viruses characterized in this study lacked a GAATATATAG fragment between the I173R and the I329L genes and were classified as IGR I variants. Furthermore, the tetrameric amino acid repeats within the CVR of the B602L gene of the 2019 Malawian ASFV reported in this study had the signature BNDBNDBNAA, 100% similar to ASFV responsible for the 2013 and 2017 ASF outbreaks in Zambia and Tanzania, respectively.Conclusions: The results of this study confirm an ASF outbreak in Karonga district in northern Malawi in September 2019. The virus was closely related to other p72 genotype II ASFV that caused outbreaks in neighboring eastern and southern African countries, emphasizing the possible regional transboundary transmission of this ASFV genotype. These findings call for a concerted regional and international effort to control the spread of ASF in order to improve nutritional and food security.

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Genetic characterization of African swine fever virus in Cameroon, 2010–2018

Cited by 35 publications

References 27 publications

Molecular Characterization of African Swine Fever Virus Isolates in Estonia in 2014–2019

Molecular Characterization of African Swine Fever Virus Isolates in Estonia in 2014–2019

Epidemiology of African Swine Fever in Piggeries in the Center, South and South-West of Cameroon

Genetic profile of African swine fever virus responsible for the 2019 outbreak in northern Malawi

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