Genetic diversity of the pandemic influenza A (H1N1) virus in Saudi Arabia.

INTRODUCTION: Pandemic influenza A (H1N1) virus emerged and spread globally in the spring of 2009. Saudi Arabia also witnessed a severe H1N1 pandemic virus epidemic with considerable morbidity and mortality in different parts of the kingdom beginning in June 2009. The influenza A(H1N1)pdm09 virus was detected in samples collected between May 2009 and November 2010 from Makkah region. This study provides data on the viral diagnosis and genetic diversity of hemagglutinin (HA) and neuraminidase (NA) genes of influenza A (H1N1)pdm09 virus from Saudi Arabia. METHODOLOGY: Nasopharyngeal swabs from 100 clinically infected patients in the peak of the outbreak were collected from Makkah region and processed for viral diagnosis by viral culture and real-time polymerase chain reaction (PCR). HA and NA genes of 10 selected samples were sequenced and analyzed. RESULTS: A total of 100 samples were collected; only 10 samples were found to be positive for influenza A virus infection by real-time PCR. Nucleotide sequence analysis of the HA and NA genes of influenza A (H1N1) from Saudi Arabia showed significant similarities with selected isolates. The phylogenetic tree constructed for both HA and NA genes formed close clusters with selected reference isolates. CONCLUSIONS: Nucleotide sequence analysis and phylogenetic relationships of the HA and NA genes of influenza A (H1N1) virus from Saudi Arabia with selected reference isolates indicates that they were genetically close and most probably originated from influenza A(H1N1)pdm09.

Two-stage PCR assay for detection of human brucellosis in endemic areas.

BACKGROUND: Brucellosis is a common zoonosis that can cause a severe febrile illness in humans. It constitutes a persistent health problem in many developing countries around the world. It is one of the most frequently reported diseases in Saudi Arabia and incidence is particularly high in the Central region, and around the city of Riyadh. The aim of this study was to evaluate a two-stage PCR assay for detection of human brucellosis particularly in endemic areas. METHODS: A total of 101 serum samples were collected from patients with acute febrile illness (AFI) of unknown cause from two different locations in the Western region of Saudi Arabia. The first location (Northern) is characterized by a nomadic rural population while the second (Central) is a modern urban city. All samples were subjected to DNA extraction and Brucella genus-specific PCR amplification using B4/B5 primers of the bcsp31 gene. Positive B4/B5 samples were subjected to multiplex species-specific Brucella PCR amplification. RESULTS: In the Northern location, 81.9% of the AFI samples were confirmed Brucella positive, while all the samples collected from the Central region proved to be Brucella negative. Samples positive for Brucella were subjected to multiplex species-specific Brucella amplification. B. abortus was detected in 10% and B. melitensis in 8% of the samples, while the majority (82%) of samples showed both B. abortus and B. melitensis. As expected, B. suis was not detected in any of the samples. CONCLUSIONS: This study concluded that a two-stage PCR assay could be useful as a rapid diagnostic tool to allow the consideration of brucellosis as a possible cause of AFI, particularly in non-urban locations. It also recommends the collection of epidemiological data for such patients to obtain further information that may help in rapid diagnosis.