Exchange Program

Thailand
Mahidol University
Mahidol-Osaka Center for Infectious Diseases(MOCID)

Date: 2013/06/05~2013/07/04
Kobe University School of Medicine Faculty ofHealth Science
Ueda ShuheiIntroduction
I would like to learn the researches that I can’t perform in Japan; therefore,
I am applying this program. In southeast Asia, there are several
mosquito-borne viral infectious diseases which are prevalent only intropical and subtropical regions.

Among them, Dengue fever is an

important one that needs to be paid attention.

Human is infected withDengue viruses by being bitten by mosquito carrying the viruses.

Now

this virus is not endemic in Japan; however, the infection cases are foundevery year among overseas travelers.

In addition, there is a possibility

that global warming potentially makes mosquitoes carrying this virus
possible to inhabit in Japan in a future. So, I would like to learn how theDengue researches are carried out among research groups in southeast
Asia.

In addition, I would also like to learn how rapid diagnostic methods

for viral infectious diseases are established.

Mosquitoes carrying dengueviruses are prevalent in southeast Asian countries including Thailand;
therefore, I believe that it is possible to learn how to perform researches
that I can’t perform in Japan. And, during the cooperation with individuals
in a foreign country, I may face the difficulties not only in conducting
research activities, but also in daily life because of possible communication
problems in a different cultural environment.

I would like to feel and findthe way to overcome such difficulties in this occasion.

About my research
Mhahidol-Osaka Center for Infectious Diseases (MOCID) is a laboratory of
Osaka University located in Mhahidol University. In this laboratory,
mosquito-borne viral infectious diseases which are prevalent only in tropicaland subtropical regions, like dengue virus and chikungunya virus areresearched. The subject of my research was “Diagnosis of Dengue Suspected
Patients In Nakhonsawan”.
Introduction
Dengue virus is transmitted by Aedes aegypti or Aedes albopictus. Denguevirus exist as 4 serotypes(Ⅰ~Ⅳ), and it cause dengue fever in 50-100million
infections per year. 2.5 billion people live in dengue-endemic tropical andsubtropical areas.
Objective
The objective of this research is diagnosis of dengue suspected patients todetect viral RNA by RT-PCR and antibodies against dengue by ELISA.
Methods
Viral RNA detection
24 acute-phase serum samples (Nakhonsawan province, febrile illness, 2013
Jan-2013 Apr, 7-56 years old) were used. RNA was extracted from sera andperformed RT-PCR using QIAamp Viral RNA Mini (QIAGEN). And dengue
universal primer was used in 1st PCR, and type specific primer was used in
2nd PCR.
Antibodies detection
18 acute-convalescent pair serum samples and 6 acute-phase serum samples
were used for ELISA (Dengue Virus IgG DxSelect, Dengue Virus IgM
DxSelect (FOCUS Diagnostics)).
Results
Viral RNA detection

In 1st PCR, 23 samples were positive and 1 was negative. In 2nd PCR, 2samples were dengue 1 and dengue 2, 7 samples were dengue 3, 3 samples
were dengue 4 and 9 samples were unknown.
Antibodies detection
23 samples were IgG positive and 1 was IgG negative. 18 samples were IgM
positive and 6 were IgM negative. About acute-convalescent IgG, most ofthem were higher index at convalescent than at acute, and they werepositive at acute. In 1 sample, IgG was negative at acute and at convalescent
IgG was positive. And in 1 sample, IgG was positive at acute and IgG wasnegative at convalescent (Table 1). Relationship between Ig level and PCR
was listed in Figure (Fig 1).

Fig 1. Relationship between Ig level and PCR
AcutePCR
GIg

M+-+

221-

10+

171-

60

Summary
24 dengue suspected serum samples were investigated by PCR and ELISA.
And 23 samples were positive and 1 was negative by PCR. It is thought thatthis 1 sample was another flavivirus patient like Japanese encephalitis virus,
because some viruses bring on similar symptom. The sample whose IgG wasnegative at acute and at convalescent IgG was positive is thought that thispatient was primary dengue infection. 1 sample was IgG positive at acute,but IgG was negative at convalescent. I don’t know why IgG became
negative.
About Thailand
I visited many places on weekend. I visited royal palace, Ayutthaya andSangkhla Buri. The place where I most enjoyed was sangkhla Buri. I rode onan elephant there.

Conclusion
I enjoyed my staying. Through this exchange program, I had wonderfulexperience. I could perform experiment using serum samples of denguepatients. And I could see the dengue fever patients. Also I could learn
cultures of Thailand. To make use of experience of this program, I want tostudy hard.