Serological Analysis of Human Pandemic Influenza (H1N1) in Thailand.

The study was aimed at determining the prevalence of pandemic influenza (H1N1) 2009 among patients with respiratory tract diseases during July-December 2009 using real-time reverse transcription polymerase chain reaction. Haemagglutination inhibition (HI) assay was performed to detect antibody titres against pandemic influenza in 255 medical personnel, 307 members of the general population during the second week of December 2009 in Khon Kaen province, Thailand, and in 100 stored sera collected from people of different age-groups during 2008. The results showed that the pandemic (H1N1) 2009 had occurred during July-December 2009. The results of the HI test after the wave of this outbreak showed that 123 (48%) of the 255 sera collected from the medical personnel, 109 (36%) of the 307 sera obtained from the general population, and only two of the 100 stored sera from 2008 contained antibodies (HI titres ≥40) against pandemic influenza. Antibody against the pandemic (H1N1) 2009 was found in at least one-third of the population. In conclusion, the prevalence of virus and serological data obtained from the study can be used as the serological background level of the Thai population after the July-December pandemic. Finally, the serological data might be useful for outbreak-prevention and control strategies and for the management of vaccination for the pandemic (H1N1) 2009 in Thailand.

Prevalence of respiratory viruses isolated from dogs in Thailand during 2008-2009.

Background: A highly contagious respiratory disease in canines is infectious tracheobronchitis or kennel cough characterized by inflammation of the upper respiratory tract. The cause of kennel cough has been associated with multiple or complex agents such as canine adeno virus (CAV), canine influenza virus (CIV), canine distemper virus (CDV), and canine para influenzavirus (CPIV). Objective: Study the prevalence of canine respiratory viruses detected from in Thailand during 2008-2009. Methods: Nasal swab samples collected from 102 healthy dogs and 109 dogs with respiratory diseases. Then CAV, CIV, CDV, and CPIV were detected by in-house nested PCR and further confirmed by nucleotide sequencing. Results: Nested PCR showed that primers designed and used in this study yielded high specificity without any non-specific amplification. The prevalence of CAV, CIV, CDV and CPIV in healthy dogs was 0%, 2.94%, 2.94%, and 0.98%, whereas that found in dogs with respiratory diseases was 9.17%, 1.83%, 2.75%, and 11.93%, respectively. In healthy dogs, co-infection with CPIV + CDV was detected in only 0.98%. On the other hand, dogs with respiratory symptoms showed multiple infections with CAV + CIV in 1.83%, CIV + CPIV in 0.92%, CAV + CPIV in 1.83%, and CAV + CDV + CPIV in 0.92%. Conclusion: The prevalence data obtained from this study may be useful for outbreak preventions and to raise awareness of potential transmission of the newly emerged canine influenza virus to humans.

Determination of antibody response to the human pandemic influenza H1N1 2009 among patients with influenza-like illness and high risk groups.

The global population has been exposed to the novel pandemic H1N1 influenza virus since mid March 2009, causing the expansion of respiratory illness around the world, including Thailand. To evaluate the an-tibody titers against human pandemic influenza (H1N1) in Thai people with influenza-like illness (ILI), 45 paired se-rum samples (acute and convalescent) were subjected to hemagglutination inhibition (HI) test and real-time RT-PCR. Most serum samples of ILI patients positive by real-time RT-PCR displayed an at least four-fold antibody in-crease of HI titers against pandemic influenza (H1N1). In addition, to determine cross-reactivity with human sea-sonal H1N1 influenza, viral antigen from the seasonal H1N1 was used to detect antibody against seasonal H1N1 influenza and all sera showed negative results. We also studied the single sera samples from the high risk medical personals collected before and after the pandemic influenza (H1N1) outbreaks for antibodies against seasonal H3 influenza virus infection. The results showed lack of cross-reactivity to the human pandemic H1N1 influenza virus. HI antibody testing to pandemic influenza (H1N1) can be used for the diagnosis, preventive and control measures of potential outbreaks.

Relationship between hybrid capture II ratios and DNA amplification of E1, E6 and L1 genes used for the detection of human papillomavirus in samples with different cytological findings.

The hybrid capture II (HCII) assay is widely used in the detection of human papillomavirus virus (HPV). However, due to the limited number of HPV genotypes, it does not permit a comprehensive typing of viruses and “grey zone” (borderline negative or positive results) are often difficult to interpret. As such, polymerase chain reaction (PCR) should be used in parallel with HCII assays, and consensus PCR detection is capable of covering a wider detection range than with the HCII method. We examined the relationship between HCII relative light unit/cut-off (RLU/CO) ratios and PCR amplification results. This was done using previously described primer sets (MY/GP) as well as with our primers for HPV E1, L1 and E6 gene amplification, and performed on samples exhibiting differ-ent cytological findings. Together, 243 samples were divided into three groups having RLU/CO ratios of < 0.4 (n = 21), 0.4-4 (n = 64) and ≥ 4 (n = 158), respectively. All samples were subjected to PCR amplification using MY/GP and the newly designed E1, L1 and E6 primers. Results were verified by direct sequencing. PCR amplification sen-sitivities were higher when using the E1 primers than for the MY/GP, E6 or L1 primers. The E1 assay can be used for HPV detection with a sensitivity of 102 copies μl-1. Samples with RLU/CO ratios exceeding 4, and grey zone samples of 0.4-4, were amplified using E1 primers in 79.74% and 26.56% of the total cases, respectively. Cytologi-cal data of grey zone samples were primarily found to be normal (77%) whereas those with RLU/CO ratios > 4 were found in any of the cytological data categories. We concluded that HPV screening by HCII for grey zone sam-ples should be analyzed together with cytological data, as well as with a PCR screening tool that incorporates the E1 primers.

Dynamics of HBV DNA levels, HBV mutations and biochemical parameters during antiviral therapy in a patient with HBeAg-negative chronic hepatitis B.

Chronic hepatitis B virus (HBV) infection leads to long-term sequelae such as cirrhosis and hepatocellular carcinoma. Antiviral therapy aims at controlling the viral replication and thus, decreasing the likelihood of such complications. In this study, we evaluated the dynamics of biochemical and virological parameters over 10 years of antiviral therapy in a Thai patient with chronic HBeAg-negative HBV infection, who had relapsed after two courses of interferon alfa treatment. Lamivudine administration initially led to a significant reduction in alanine aminotransferase (ALT) and HBV DNA levels, but a subsequent emergence of YIDD mutants caused an ALT flare and a virus breakthrough. A 4-log HBV DNA decrease and normalization of the ALT level were achieved within 3 months of adefovir monotherapy without any relapse during follow-up exceeding 20 months. Thus, careful monitoring during treatment and knowledge of cross-resistance to antiviral salvage therapy are crucial for the management of patients with chronic hepatitis B.

The spread of avian influenza H5N1 virus; a pandemic threat to mankind.

Influenza A H5N1 virus infection presents a major public health problem in Asian and Eurasian countries. The World Health organization has voiced their concerns about a potential pandemic with the imminent threat to humankind. In 1997, an outbreak of highly pathogenic H5N1 virus emerged and caused severe systemic disease among poultry and humans in Hong Kong. This article reviews the magnitude of the 2004-2006 outbreaks in various countries and highlights the highly pathogenic avian influenza (HPAI) subtype H5N1 virus as the cause of a major epidemic with potentially vast repercussions on economics, public health and society at large. Not only has this avian influenza (AI) virus infected poultry but has also proven highly pathogenic and fatal to mammalian species including humans and felines. The present review draws a comprehensive picture encompassing epidemiology, inter-species transmission and genetic characterization of this highly virulent virus. Moreover, laboratory diagnostic techniques, vaccination strategies and antiviral therapies aimed at outbreak control and management are also discussed.

Malassezia furfur in infantile seborrheic dermatitis.

Our objective was to study both incidence and various strains of Malassezia in infantile seborrheic dermatitis (ISD). Sixty infants between 2 weeks and 2 years old with clinical diagnosis of ISD at the Department of Pediatrics, King Chulalongkorn Memorial Hospital from May 2002 to April 2003 were recruited. Malassezia spp. were isolated from cultured skin samples of the patients, genomic DNA was extracted and the ITS1 rDNA region was amplified. The PCR product was examined by agarose gel electrophoresis and DNA sequences were determined. The ITS1 sequences were also subjected to phylogenetic analysis and species identification. ISD is most commonly found in infants below the age of 2 months (64%), followed by those between 2 and 4 months (28%) old. Cultures yielded yeast-like colonies in 15 specimens. PCR yielded 200-bp products (Candida) in 3 patients and 300-bp products (Malassezia furfur) in 12 patients (18%). Sugar fermentation using API 20C aux performed on the three 200-bp PCR products yielded Candida species. M. furfur was the only Malassezia recovered from skin scrapings of children with ISD.