Prevalence rates of Giardia and Cryptosporidium among diarrheic patients in the Philippines.

The prevalence of Giardia and Cryptosporidium among 3,456 diarrheic patients corrected from May 2004 to May 2005 in the Philippines was determined. Of 133 (3.8%) positive samples, 69 (2.0%) were positive for Giardia and 67 (1.9%) for Cryptosporidium. Three samples had co-infection with Giardia and Cryptosporidium. Luzon had the highest positive samples (5.0%) followed by Mindanao (4.9%), then Visayas (2.2%). Giardia was most prevalent in Mindanao (3.6%) while Cryptosporidium was most prevalent in Luzon (3.1%). The prevalence of Giardia (2.0%) among pediatric patients (0-18 years) did not significantly differ from that (1.9%) among adults (> 18 years old). However, for Cryptosporidium, the prevalence (2.9%) among pediatric patients was significantly higher compared to that (0.2%) among adult patients. In the pediatric population, the highest percentage of patients with Giardia was the 5-9 year old age group, while that of Cryptosporidium was in the 0-4 year old group. The prevalence of Giardia, but not Cryptosporidium, was significantly higher in male than female adults. Seasonality had a distinct peak in September with Cryptosporidium more prevalent in the rainy (2.6%) than dry season (0.9%).

Antigen sandwich ELISA predicts RT-PCR detection of dengue virus genome in infected culture fluids of Aedes albopictus C6/36 cells.

Antigen detection by sandwich ELISA was evaluated to predict RT-PCR detection of dengue viral genome in infected culture fluid of Aedes albopictus clone C6/36 cells. Serum specimens collected from dengue patients within 5 days from onset of fever in 2 hospitals in Metro Manila, Philippines, were inoculated into C6/36 cells, and incubated at 28 degrees C. A total of 282 infected culture fluid specimens were harvested and examined by sandwich ELISA and RT-PCR to detect dengue viral antigen and genome, respectively. In the sandwich ELISA, the P/N ratio was calculated by dividing optical density (OD) of a given test specimen by the OD of the standard negative specimen. Samples with a P/N ratio > or = 4.001 were positive for viral genome detection by RT-PCR. The sensitivity and specificity of antigen sandwich ELISA with RT-PCR as the standard, were 90.4% and 100%, respectively. Although antigen sandwich ELISA is less sensitive than RT-PCR, its usefulness lies in its capability to screen a large number of samples at a minimum cost, especially during an outbreak. Samples that meet a set cutoff value can undergo confirmation by RT-PCR for further epidemiological studies.