The authors would like to thank Mr Ronnachai
Sanmai, Mr Kongkrit Sriburin, Mr Rerngsak Sarakam,
Ms Ruja Datchaipitak and Ms Pornthip Rungruang, the
Table 3. Plasmodium infections among 241 migrant workers
diagnosed by microscopy and semi-nested multiplex PCR
(SnM-PCR)
Species No. of positives
Total SnM-PCR Microscopy
P. falciparum 8 (53.3) 7 (87.5) 2 (25)
P. vivax 6 (40) 6 (100) 2 (33.3)
P. malariae 1 (6.7) 1 (100) 0
P. ovale 00 0
Total 15 14 (93.3) 4 (26.7)
Figures in parentheses indicate percentages.
infections tested by semi-nested PCR (5.8%; 14 of 241)
was higher than that of microscopy (1.7%; 4 of 241). There
was highly significant difference in the prevalence between
the two laboratory methods (p < 0.001). As shown in Fig.
2, the SnM-PCR and microscopy showed concordant results
in 229 blood samples including 3 positive cases and
226 negative cases. However, 12 non-concordant results
between microscopy and SnM-PCR were that one microscopy
positive sample was not detected by semi-nested PCR
and microscopy could not detected 11 SnM-PCR positive
samples.
DISCUSSION
Our study revealed that 6.2% of foreign migrant workers
infected with malaria parasites. Higher prevalence
was found in these workers as compared to 0.055% of
Thai people2. It is likely due to low socioeconomic status
in migrant workers. Poor economy in migrants has resulted
in the difficulty to access healthcare services and
Fig. 2: Malaria detection by semi-nested PCR (SnM-PCR) and
microscopy. The numbers of positive cases were shown in
circles and the sensitivity was expressed as percentage in
parentheses. (n = Total number of the samples examined).
218 J Vector Borne Dis 48, December 2011
fourth year medical technology students of Rangsit University,
for their technical help. This project was financially
supported by Rangsit University and Faculty of
Medical Technology, Mahidol University, Thailand