Enterobius vermicularis infection among pre-school children in Karen hilltribe villages in Chiang Mai, Thailand.

We surveyed Karen hilltribe villages in the Mae Chaem District of Chiang Mai Province between April and May 2001. Two hundred and forty-nine pre-school children were selected by stratified sampling from 10 villages and were examined for Enterobius vermicularis eggs by the Scotch tape perianal examination technique. One hundred and thirteen (53 boys and 60 girls) were found to have E. vermicularis eggs, giving an overall infection rate of 45.38%. We were able to determine that E. vermicularis infection is prevalent among the children of these hilltribe villages.

Malaria among hilltribe communities in northern Thailand: a review of clinical manifestations.

Malaria is an important vector-borne disease in the tropics. Northern Thailand is endemic for malaria. We reviewed the clinical manifestations presented by patients with malaria; our data were drawn from the database of Mae Chaem Hospital, Chiang Mai Province. Mae Chaem district is hilly and rural. More than 80% of the district's population are members of hilltribes. The database showed that between July 2000 and April 2001, a final diagnosis of malaria was made in 94 cases. The commonest clinical manifestation was fever (in 91 cases; 96.8%), followed by chills (in 57 cases; 60.6%). Interestingly, some unusual presentations such as petechiae, abnormal menstruation, and jaundice were also found.

Monitoring of lead exposure among mechanics in Bangkok.

Lead is an important heavy metal used in many industrial processes. It plays an important role in the pathogenesis of both acute and chronic toxicity. Mechanics have a high risk of benzene exposure but tend to be a forgotten occupational group in Thailand. In this study, monitoring of lead exposure by anodic stripping voltammetry (ASV) determination of blood lead levels was conducted for 69 subjects (29 control subjects and 40 mechanics). The mean blood lead level in the control group was 6.59 +/- 1.98 microg/dl. The mean blood lead level in the mechanics was 11.24 +/- 5.82 microg/dl. There was a significant difference between the two groups (p < 0.05). Based on this study, consideration of the prevention of exposure to lead among mechanics as a public health strategy is recommended.

Feasibility of urinary trans, trans-muconic acid determination using high performance liquid chromatography for biological monitoring of benzene exposure.

Benzene is an important carcinogenic substance used in many industrial processes. Inhalation of this substance can cause both acute and chronic toxicity. In this study, monitoring of benzene exposure by high-performance liquid chromatography (HPLC) for urine trans, trans-muconic acid (ttMA) determination was adapted. We described a new adapted sensitive and specific HPLC method. We mixed 0.5 mL of urine sample with 2 mL of Tris Buffer containing vanillic acid as internal standard (IS) and percolate this through a preconditioned ion-exchange column. After rinsing the column with phosphoric acid solution, acetate buffer, and deionized water, we eluated the analytes with 2 mL of an equivolume solution of 1.5 mol/L sodium chloride and methanol. Of this, 10 microliter was injected into the HPLC column. The mobile phase consisted of, per liter, 10 ml of acetic acid, 100 ml of methanol, and 5 mmol/L sodium acetate. The flow rate was started at 1.2 ml/min. The ttMA and IS were detected at 4.2 to 4.4 and 12.6-13.3 minutes, respectively. The lowest detection limit was 0.05 mg/L.

Urine trans,trans-muconic acid determination for monitoring of benzene exposure in mechanics.

Benzene is an important carcinogenic substance used in many industrial processes. Inhalation of this substance can cause both acute and chronic toxicity. In this study, monitoring of benzene exposure by high-performance liquid chromatography for urine trans,trans-muconic acid (ttMA) determination in 94 subjects, (49 control subjects and 45 mechanics) was performed. The mean urine ttMA level in the control group was 0.116 +/- 0.027 mg/g creatinine. The mean urine ttMA level in the mechanics group was 0.280 +/- 0.131 mg/g creatinine. There was a significant difference between the groups (p < 0.05). Based on this study, we recommend the use of urine ttMA determination for monitoring of benzene exposure in high risk workers.