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ABSTRACT: Alkhumra hemorrhagic fever virus (AHFV) is an emerging flavivirus that was discovered in 1994-1995 in Saudi Arabia. Clinical manifestations of AHFV infection include hemorrhagic fever, hepatitis, and encephalitis, with a reported mortality rate as high as 25 %. Biological characteristics of this virus have not been well defined. Agglutination of erythrocytes (hemagglutination) is a laboratory tool for studying the attachment of viruses to cellular receptors. The envelope protein contains sites for attachment to host receptors to initiate the process of infection and is thus an essential component of the virion. In the present study, we examined the ability of AHFV to agglutinate erythrocytes of 13 mammalian and avian species (human group O+, camel, cow, sheep, goat, rabbit, guinea pig, mouse, rat, chicken, duck, goose and turkey) with and without trypsin-treatment. Without trypsin treatment, AHFV failed to agglutinate erythrocytes of all examined species. Following trypsin treatment, AHFV agglutinated erythrocytes of five species, namely, goose, human group O+, rat, guinea pig, and mouse, in descending order of sensitivity. This trypsin-dependent hemagglutination test has potential for use in serological and functional studies of AHFV.
Archives of Virology 09/2012; · 2.11 Impact Factor
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Transactions of the Royal Society of Tropical Medicine and Hygiene 05/2012; · 2.16 Impact Factor
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Intervirology 03/2012; 55(4):259-60; author reply 261-2. · 2.34 Impact Factor
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ABSTRACT: RT-PCR to detect Alkhumra virus (ALKV) RNA in plasma or serum has been the standard practice to confirm this infection in the first seven days of illness. In this study, RT-PCR detection of viral RNA from the plasma, serum, and buffy coat (BC) was compared to virus isolation. Plasma, serum, and BC were obtained from seven patients with clinically suspected ALKV infection in Najran, Saudi Arabia. Baby hamster kidney (BHK-21) and rhesus monkey kidney (LLC-MK2) cell culture monolayers were used for virus isolation. Real-time RT-PCR was used to confirm ALKV infection and to detect viral RNA directly from plasma, serum, and BC. ALKV was isolated from five of the seven patients. The virus was isolated from all three specimen types (plasma, serum, and BC) of the five confirmed patients. ALKV RNA was detected directly by RT-PCR in BC in all five (100%) culture-positive patients and in plasma or serum in only four (80%) of the five patients. Three of the five patients for whom ALKV RNA was detected in BC also had detectable viral RNA in plasma and serum. In the remaining two patients with detectable ALKV RNA in the BC, the plasma was positive but the serum was negative in one patient, whereas the serum was positive and the plasma was negative in the other patient. The use of real-time RT-PCR to detect ALKV RNA in the BC was superior to using plasma and serum and equivalent to virus isolation.
Archives of Virology 02/2012; 157(5):819-23. · 2.11 Impact Factor
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ABSTRACT: Epidemiological data suggest that Alkhumra (misnamed as Alkhurma) virus (ALKV) is transmitted from livestock animals to humans by direct contact with animals or by the mosquito bites, but not by ticks. To assess the ability of the virus to replicate in mosquito cells, serum and plasma of seven acutely febrile patients with clinically suspected ALKV infection reported in Najran, Saudi Arabia in 2009 were inoculated onto Aedes albopictus mosquito cells (C6/36) and directly examined with ALKV-RNA-specific real time RT-PCR as well as indirect immunfluorescence assay (IFA) using ALKV-specific polyclonal antibodies. The isolated virus was titrated in the mammalian rhesus monkey kidney cells (LLC-MK2). Five of the seven specimens were RT-PCR- and culture-positive demonstrating cytopathic effects in the form of cell rounding and aggregation appearing on day 3 post inoculation with syncytia eventually appearing on day 8 post inoculation. Identification of ALKV-RNA in the cell culture was confirmed with RT-PCR and IFA. The virus titre was 3.2×10(6) tissue culture infective dose 50 (TCID(50)) per mL. Three more viral passages were successfully made in the C6/36 cells. This is the first description of propagation of ALKV in mosquito cells.
Transactions of the Royal Society of Tropical Medicine and Hygiene 12/2011; 106(3):180-5. · 2.16 Impact Factor
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ABSTRACT: After its first appearance in Alkhumra district of Jeddah in 1994-1995, and then in Makkah in 2001-2003, the new hemorrhagic fever virus, known as Alkhumra (misnamed as Alkhurma) virus (ALKV), has subsequently been reported from Najran, in the south border of Saudi Arabia.
This is a descriptive cohort study summarizing the epidemiological, clinical, and laboratory characteristics of ALKV infected patients diagnosed in Najran from 1 August 2003 through 31 December 2009.
A total of 148 suspected cases were reported, of which 78 (52.7%) cases were laboratory confirmed; 2 cases in 2003, 1 case in 2004, 4 cases in 2005, 1 case in 2007, 12 cases in 2008, and 58 cases in 2009. The cases were reported year round but 64.1% (50/78) of them occurred in the summer time. Twenty-five (32.1%) cases occurred as clusters in 5 families. The virus seemed to be transmitted from livestock animals to humans by direct contact with these animals and likely by mosquito bites. Ticks did not seem to be involved in the transmission of infection from animals to humans. Clinical and laboratory features included fever (100%), headache (85.9%), malaise (85.9%), arthralgia (83.3%), anorexia (82.1%), myalgia (82.1%), backache (71.8%), nausea and vomiting (71.8%), chills (60.3%), retro-orbital pain (55.1%), diarrhea (51.3%), abdominal pain (48.7%), hemorrhagic manifestations (25.6%), central nervous system manifestations (23.1%), leucopenia (87.7%), elevated liver enzymes (85.7%), prolonged partial thromboplastin time (52.6%), thrombocytopenia (46.2%), elevated creatine kinase level (45.7%), and elevated lactate dehydrogenase (25.0%).
ALKV infection has now been recognized outside its original boundaries in Saudi Arabia which may herald its identification in other countries.
The Journal of infection 10/2010; 62(1):67-76. · 4.13 Impact Factor
