Application of geographic information system in TSH neonatal screening for monitoring of iodine deficiency areas in Thailand.

By applying the WHO/UNICEF/ICCIDD guidelines for the Assessment of Iodine Deficiency Monitoring using Thyroid Stimulating Hormone (TSH) with the use of a Geographic Information System technique, the degree of severity of iodine deficiency for various areas can be evaluated. In this study, TSH data for neonates born in all 76 provinces of Thailand during 2003-2006 were classified according to their spatial demographic information. The results show that all provinces in Thailand suffer from iodine deficiency at mild to moderate levels, and the degree of severity increases year by year. The number of provinces with iodine deficiency were 10, 12, 35 and 36 for the years 2003, 2004, 2005 and 2006, respectively. This trend shows that each province in Thailand is at risk for iodine deficiency. Public health decision makers need to be aware of this problem anddevelop a program to eliminate iodine deficiency.

Stability of genomic DNA in dried blood spots stored on filter paper.

The stability of DNA in dried blood samples obtained from the neonatal screening program in Thailand was retrospectively studied in order to determine the conditions necessary for the long term storage of samples for DNA banking. Specimens from 1991 to 2001, which had been kept in the ambient conditions at the Department of Medical Science, Ministry of Public Health, Thailand, were randomly sampled and used for the study. Genomic DNA was extracted from the samples and DNA fragments of the PAX8 and beta-globin genes were amplified by PCR to determine DNA stability. The study showed that 255-bp and 674-bp fragments of the PAX8 gene could be amplified from all the samples. The DNA fragment of 1,039 bp of the beta-globin gene could be detected in all of the samples for the years 1993 to 2001, but only in seven and five out of the ten studied samples for each of the years 1991 and 1992, respectively. Our study shows that genomic DNA is stable in dried blood stored on filter paper at ambient tropical conditions for at least 11 years. However, DNA quality for amplification of larger DNA fragments decreased when the specimens were stored for longer than 10 years.

A study to implement early diagnosis of HIV infection in infants born to infected mothers.

A protocol for detecting HIV DNA from specimens collected on filter papers and the effect of storage temperatures on determination of HIV DNA from dried blood spots has been developed and optimized. Blood specimens collected from HIV-1 infected and normal persons were spotted onto blood collection cards (Whatman BFC 180). The HIV DNA was extracted by phenol-chloroform-isoamyl alcohol and was detected for C2V4 of HIV-1 env by nested polymerase chain reaction (nested PCR). One set was stored at -20 degrees C for 14 weeks, another at 37 degrees C for 1 week and then kept at -20 degrees C for 13 weeks and a third set at 25 degrees C for I week and then -20 degrees C for 13 weeks. The dried blood spots from each set were detected for the HIV DNA every 2 weeks for 14 weeks. The C2V4 region of HIV env DNA was determined from small amounts of the dried blood collected on the filter papers. The nested PCR procedure could detect as few as 5 copies of HIV proviral DNA, and HIV DNA could be detected from specimens with viral loads of 2x 10(4) copies/ml. HIV DNA could be detected from specimens collected at all temperatures tested for at least 14 weeks. Therefore, laboratory diagnosis of HIV infection can be done by PCR on dried blood spots. These techniques will be useful as a tool for studying the epidemiology of HIV infection among populations of interest such as mother to child infection using newborn screening specimens.

Congenital adrenal hyperplasia: should nationwide screening be implemented in Thailand?

A project to establish the Thailand National Neonatal Screening Program was started in 1996 with the objective of screening every newborn for congenital hypothyroidism and phenylketonuria. Over a million newborns were screened and over 430 abnormal cases were detected. A study was also conducted to determine the feasibility of including CAH screening in the program. The incidence of this disease has not yet been clearly determined. Since 1999, 58,563 newborns have been screened for CAH and 144 newborns with serum 17-OHP higher than 40 ng/mL were recalled for confirmatory tests. Of those, 68 were retested and 6 were found to have elevated 17-OHP levels. Two were confirmed with salt wasting CAH one month after birth, two others were diagnosed with another disease that caused electrolyte imbalance, one patient died, and the sixth required further clinical diagnosis. Five other babies were reported dead before the second specimens could be collected for confirmation. It appears that CAH may be one of the underlying causes of death among Thai newborns and the incidence may be higher than thus far shown due to incomplete confirmation of positive screens and deaths to some infants.

Neonatal screening program in Thailand.

The Neonatal Screening Program for congenital hypothyroidism (CHT) and phenylketonuria (PKU) commenced in 1996 with the objective of bringing better quality of life to people throughout the country, especially in the remote areas. This involved the implementation of routine services to the public health infrastructure all over the country. The plan of action has been designed so that by the year 2000 all public health service units throughout the country may provide screening services which can cover 1.2 million babies/ annum. Implementation of the screening program has been performed through public health sectors all over the country. These involved: education of the health personnel and communities, implementation of routine specimens collection and delivery systems to the central laboratories, establishment of central laboratory screening services, routine follow up and case management. Local in-house reagents using ELISA and IRMA techniques have been developed and utilized as screening and confirmation tests for CHT. In addition, Guthrie's test has been used for PKU screening and the automated Fluorometry has been selected for PKU confirmation. All 724 community hospitals have provided newborn screening services as one of the basic requirements for newborns according to public health policy. Of 1,425,025 babies screened, 3,450 (0.24%) were above the first screening cut off for CHT (TSH > 25 mU/l) and 321 (0.02%) for PKU (PKU > 4mg/dl). With a 63.10% follow up rate, the incidences were 1:3,314 for CHT and 1:237,504 for PKU. Newborn screening has been implemented as routine practice for all public health sectors of the country for CHT and PKU. It is expected that by the year 2003, all Thai newborns will be provided with screening services resulting in a better quality of life for the next generation.