Browsing by Author "Khaiseb, S."

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    Avian influenza H5N8 outbreak in African penguins (Spheniscus demersus), Namibia, 2019
    (2020) Molini, Umberto; Aikukutu, Gottlieb; Roux, Jean-Paul; Kemper, Jessica; Ntahonshikira, Charles; Marruchella, Giuseppe; Khaiseb, S.; Cattoli, Giovanni; Dundon, William G.
    In January 2019, high mortalities were reported among African Penguins (Spheniscus demersus) in a breeding colony on Halifax Island, Namibia, Africa. Analysis of samples by reverse transcription quantitative PCR indicated the presence of highly pathogenic avian influenza (HPAI) subtype H5N8. Sequence analysis of the hemagglutinin and neuraminidase genes confirmed the presence of the virus in the birds and its high similarity to HPAI subtype H5N8 identified in South Africa in 2017. There have been no previous reports of HPAI H5N8 in Namibia.
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    Complete coding sequences of lumpy skin disease virus strains isolated from cutaneous lesions in Namibian cattle during 2016 outbreaks
    (2020) Di Felice, Elisabetta; Pinoni, Chiara; Khaiseb, S.; Camma, Cesare; Dondona, Andrea Capobianco; Polci, Andrea; Molini, Umberto; Monaco, Federica
    Between September and October 2016, an outbreak of lumpy skin disease (LSD) was monitored in the Okakarara veterinary district of Namibia. The complete coding sequences were obtained for LSD virus isolates from skin nodules from two symptomatic animals.
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    Investigation of infectious laryngotracheitis outbreaks in Namibia in 2018
    (2019) Molini, Umberto; Aikukutu, Gottlieb; Khaiseb, S.; Kahler, Barbara; Van der Westhuizen, Jolandie; Cattoli, Giovanni; Dundon, William G.
    Between July and August 2018, two outbreaks of infectious laryngotracheitis caused the death of over 116,000 commercial poultry (layers and broilers) near the city of Windhoek, Namibia. A third outbreak occurred in September 2018 in the north of the country approximately 800km from the original outbreaks. Sample collection and molecular epidemiological analyses revealed that the outbreaks were most likely caused by poor vaccination practices leading to the reversion to virulence of an ILT vaccine strain. The analyses also indicate that inaccurate declarations were made by one of the farms involved and that illegal movement of animalsmost likely occurred.
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    Molecular characterisation of infectious bursal disease virus in Namibia, 2017
    (2019) Molini, Umberto; Aikukutu, Gottlieb; Kabajani, Juliet; Khaiseb, S.; Cattoli, Giovanni; Dundon, William G.
    Between July and September 2017, samples collected from six unvaccinated chickens in Namibia were shown to be positive for infectious bursal disease virus (IBDV) by RT-PCR. Partial sequence and phylogenetic analysis of the VP1 and VP2 genes from six viruses revealed that they all belong to the very virulent pathotype (Genogroup 3) and are genetically very similar to IBDVs identified in neighbouring Zambia. This is the first molecular characterisation of IBDV in Namibia and has implications on the control and management of the disease in the country.
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    Molecular characterization of African swine fever virus from outbreaks in Namibia in 2018
    (2019) Molini, Umberto; Mushonga, Borden; Settypalli, Tirumala B. K.; Dundon, William G.; Khaiseb, S.; Jago, Mark; Cattoli, Giovanni; Lamien, Charles E.
    Five samples were collected from four suspected outbreaks of African swine fever in Namibia in 2018. Sequencing of the C‐terminus of the B646L gene (p72 protein), the central hypervariable region (CVR) of the B602L gene, the E183L gene (p54 protein) and the CD2v (used to determine the serogroup) was performed on DNA isolated from the samples. Phylogenetic analyses of the B646L (p72) revealed that one of the samples belonged to genotype I while the remaining samples could not be assigned to any currently known genotype. In contrast, by using the E183L gene three of the samples were shown to belong to genotype Id and only two were of unknown genotype. Based on the analysis of the partial CD2v amino acid sequences of four of the samples, one of the viruses clustered with serogroup 2 while the other three did not cluster within any of the eight known serogroups. Examination of the CVR identified three variants with 8, 18 and 24 tetrameric tandem repeat sequences. This study indicates that at least three different genetically distinct ASFV are currently present in Namibia.
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    Serological evidence of coxielosis in sheep farms of Namibia
    (2018) Bishi, Alec S.; Khaiseb, S.; Shaanika, A.; Nambinga, E.K.N.; Kandiwa, Erick; Mushonga, Borden; Samkange, Alaster; Tjipura, G.
    (Query fever) is a zoonotic disease caused by Coxiella burnetii infection, which is an obligate gram negative intracellular bacterium (Lai et al., 2014). Its preferred target host cells are tissues, macrophages and circulating monocytes. Domestic ruminants, a wide variety of domestic and wild animal species are implicated as reservoirs for most human infections (Matthewman et al., 1997; Sellens et al., 2016). Transmission to humans and other animals commonly occurs by contact with animal after births or by pathogen-contaminated dust or aerosols, via tick bites or contaminated milk ingestion (Anderson et al., 2015; Njeru et al., 2016). Coxiellosis in domestic ruminants causes abortions and stillbirths, resulting in significant economic losses (Anderson et al., 2015; Joulie et al., 2015). In the some studies, sero-prevalence figures in cattle (7.4-51.1%), sheep (6.7-20.0%), camels (20.0-46.0%) and goats (20.0-46.0%) revealed variation based on eco-regions and year of study (Njeru et al., 2016). The primary objective of this study was to establish whether or not coxiellosis present in the study area.
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    Seroprevalence of African horse sickness in selected donkey populations in Namibia
    (University of Namibia, 2020) Molini, Umberto; Zaccaria, Guendalina; Kandiwa, Erick; Mushonga, Borden; Khaiseb, S.; Ntahonshikira, Charles; Chiwome, Bernard; Baines, Ian John; Madzingira, Oscar; Savini, Giovanni; D’Alterio, Nicola
    Background and Aim: African horse sickness (AHS) is a non-contagious viral disease of horses and other equids caused by an arbovirus belonging to the Reoviridae family and genus Orbivirus. AHS is an endemic disease that is responsible for the death of a high number of horses every year in Namibia. At present, there is no information on the prevalence and distribution of AHS virus (AHSV) serotypes in the different regions of Namibia. Therefore, this survey aimed to fill this knowledge gap by investigating the AHSV seroprevalence in Namibian donkeys. Materials and Methods: A total of 260 blood samples (20 samples for each region) were randomly collected from donkeys aged between 3 and 5 years. Sera were screened for AHSV-specific immunoglobulin G antibodies using a commercial competitive enzyme-linked immunosorbent assay kit and samples positive to AHSV antibodies were further tested by serum neutralization (SN) assay to evaluate the AHSV serotype-specific immune response. Results: Seroprevalence of antibodies against AHSV in Namibian donkeys was 63.5%. The AHSV prevalence was significantly higher in the northern region (64%) than in the southern region (36%). A significantly (p<0.05) higher number of donkeys had antibodies against AHSV-6 (37.8%) and AHSV-9 (37.8%). The AHSV-2, AHSV-6, and AHSV-9 prevalence were higher (p<0.05) in the northern regions compared to the southern regions. None of the donkeys in this study, however, tested positive for AHSV-8. Conclusion: Results of the current study indicate that all AHSV serotypes have either circulated previously or are circulating in Namibia except for AHSV-8. In particular, AHSV-1, -2, -3, -4, -5, -6, and -9 serotypes have circulated or are circulating in the northern region of Namibia, while AHSV-1, -4, -5, -6, -7, and -9 have infected donkeys in the south. AHSV-9 and AHSV-6 were the most prevalent serotypes detected in donkeys in this study. SN results showed that several donkeys from Kavango East, Kavango West, and Ohangwena regions had been exposed to multiple serotypes, indicating the possibility of cocirculation of several strains in Namibia.