Clinical features and differences between child and adult dengue infections in Rayong Province, southeast Thailand.

A retrospective study was conducted among patients with dengue infection admitted to Rayong Hospital during September 2004-September 2005. Data were collected from medical charts and outpatient records created when the patients came to the hospital. Of the patients diagnosed with dengue, only 301 who met the WHO criteria for dengue fever and DHF/DSS were selected. The study cohort was comprised of 147 children (76 males, 71 females) and 154 adults (71 males, 83 females), with an overall mean age of 17.6 years. Some adult clinical symptoms were different from the children. Headache and myalgia were more common among adults (p < 0.05), but cough, vomiting, abdominal pain, and rash were more common among children (p < 0.05). Among the major bleeding symptoms, epistaxis (nasal bleeding) was more common in children (p = 0.012) and gum bleeding was more common in adults (p < 0.001). Myalgia was more likely in less severe grades of infection. Adults showed some different clinical manifestations of dengue infection from children. It is necessary for health personnel to take these differences into consideration when seeing probable cases of dengue infection.

Duplex PCR-hybridization based detection of pathogenic Leptospira in environmental water samples obtained from endemic areas in northeast region of Thailand.

Leptospirosis, a major health problem worldwide, is known to be endemic in the northeastern part of Thailand with the risk of infection by exposure to pathogenic Leptospira in contaminated aquatic environment. A method based on PCR-hybridization detection of pathogenic Leptospira in water was established. The method included filtration of water sample through membrane filters of two pore sizes, DNA extraction from filters using a guanidine thiocyanate extraction method, a duplex-PCR assay with two primer pairs, and hybridization with a synthetic LipL32 DNA probe. The duplex-PCR allowed detection of two products of 279 bp for LipL32 gene and 430 bp for 16S rRNA gene. In water samples artificially seeded with serovar bratislava, at least 10(3) cells could be analyzed by PCR-agarose gel electrophoresis and 1-10 cells by PCR-Southern blot hybridization. The protocol was applied to the detection of pathogenic Leptospira in environmental waters collected from endemic areas in the northeast region of Thailand. Of 100 water samples analyzed, 23 samples were positive for pathogenic Leptospira with PCR performed with Southern blot hybridization only, but none was detected by PCR-agarose gel-electrophoresis. However, PCR performed with the chemiluminescent LipL32 probe using the Fluorescein ULS labeling facilitated the detection of low numbers of pathogenic Leptospira in water. This method should prove useful for monitoring of pathogenic Leptospira pollution in environmental waters, and has the potential to become a valuable tool to the surveillance of leptospirosis in endemic areas, thus leading to enhanced public health protection.

An enrichment broth culture-duplex PCR combination assay for the rapid detection of enterotoxigenic Clostridium perfringens in fecal specimens.

An enrichment broth culture-duplex PCR combination assay was devised to identify Clostridium perfringens directly from fecal samples. The method consists of a combination of short enrichment of samples in selective media, DNA isolation, and performing duplex PCR using two pairs of primers which identify C. perfringens strains that harbor the virulence enterotoxin gene. Comparison of two selective enrichment media and two incubation temperatures showed that the reinforced clostridial medium with neomycin was better than the fluid thioglycollate medium with neomycin (p<0.001); and incubation at 37 degrees C vs 45 degrees C showed no statistically significant difference (p=0.238). The optimal short time for pre-enrichment culture was 4 hours. The developed assay was applied to detect phospholipase C (plc) and enterotoxin (cpe) genes for C. perfringens in feces inoculated artificially with enterotoxigenic C. perfringens. The method could detect both gene products in samples inoculated with a minimum of 10(4) CFU per ml. When the method was applied to detect enterotoxigenic C. perfringens in 198 diarrhea patients, C. perfringens was found in 121 samples; 7 out of 121 samples were positive for both plc and cpe (prevalence of 5.8%). These results indicate that the developed assay was a suitable method for the rapid and specific detection of enterotoxigenic C. perfringens directly in fecal specimens of diarrhea patients, which will assist epidemiological investigations of food poisoning outbreaks and quality control of food products.

Typing of dengue viruses in clinical specimens from central Thailand.

Typing of dengue viruses was done for clinical specimens from a total of 136 patients (children under 15-years-old) suspected of having dengue virus infections and who had been admitted to Pathum Thani Provincial Hospital during the period May 1999 to April 2000. Altogether, 44 strains were isolated (isolation rate: 32.4%), consisting of 18 DEN-1, 18 DEN-2, 7 DEN-3 and 1 DEN-4. The isolation rate decreased according to the number of days after the onset of disease, from day 4 to day 8.