Sir,

We compliment Al-Araimi and colleagues for recommending prospective awareness for medical personnel about 
different travel-related tropical diseases including dengue fever.1 

Their 38 year-old Sri Lankan patient1 tested negative with polymerase chain reaction giving an equivocal result 
for Dengue IgM. Serum sample(s) collected after two or more months should be tested for Dengue IgG. In all 
probability, the levels of IgM and dengue virus ribonucleic acid had reached undetectable levels. The demonstration 
of dengue virus IgG would reconfirm the initial diagnosis.1

In countries known to be free of dengue virus infection, travel-related importation would be a problem for 
clinicians and laboratory personnel. A point-of-care assay for dengue virus non-structural protein1 (NS1) antigen, 
anti-dengue IgM and IgG would be very practical. During the initial phase of illness, NS1 would be the earliest 
datable marker in any primary or secondary infection. That would be followed by an appearance of IgM in a 
primary infection or IgG in a secondary infection. 

The results of the 23 dengue-virus positive cases detected at the Narita Airport Quarantine Station, Japan are 
of interest in this regard.2 There was almost identical sensitivity of the dengue virus (DENV) NS1 antigen detection 
by the ELISA and the rapid test. The IgM/IgG detection, employing either the antibody-capture ELISA or the rapid 
test, was not found to be suitable to identify any DENV-carrying individuals arriving in countries reported to be 
dengue free. 

The utility of a single-step immunochromatograhic one step dengue NS1 Ag and IgG/IgM test, (Dengue 
Duo; Standard Diagnostics, Inc, St.Ingbert, Germany: www.standard.com) was immense during the 2010 DENV 
outbreak in Delhi, India. Among 175 suspected cases, 86 were NS1 positive and 89 were NS1 negative. Among 86 
NS1-positive patients, 23 were IgM positive, four were IgG positive and six were positive for all three markers. The 
89 NS1-negative patients included two who were IgM positive, eight who were IgG positive and seven who were 
positive for both IgM and IgG: 72 were negative for all three markers and 53 patients were positive exclusively for 
NS1. Using the Dengue Duo test, it was possible to diagnose 61 additional patients: these NS1 positives included 
57 who were negative for IgM and four who were positive for IgG only.3

To conclude, awareness among medical and health care personnel in dengue free countries1 as well rapid 
disease diagnosis would ensure better clinical management and public health response to halt any local dengue 
transmission.

*Subhash C. Arya and Nirmala Agarwal
Sant Parmanand Hospital, Delhi, India

*Corresponding Author email: subhashbhapaji@gmail.com

References
1. Al-Araimi H, Al-Jabri A, Mehmoud A, Al-Abri S. Dengue haemorrhagic fever presenting as acute abdomen. Sultan Qaboos Univ 

Med J 2011; 11:265–8, Epub. 15 May 2011.

2. Sugimoto M, Haseyama M, Ishida Y, Yoshida S, Kamiya K. Evaluation of nonstructural 1 protein rapid test for dengue virus at the 
Narita Airport quarantine station, Japan. Jpn J Infect Dis 2011; 64:169–70.

3. Arya SC, Agarwal N, Parikh SC. Usefulness of detection of dengue NS1 antigen alongside IgM plus IgG, and concurrent platelet 
enumeration during an outbreak. Trans R Soc Trop Med Hyg 2011; 105:358–9.

SQU Med J, November 2011, Vol. 11, Iss. 4, pp. 531, Epub. 25th Oct 11
Submitted 5th Jun 11
Accepted 14th Sep 11

رد على: البطن احلادة كعرض حلمى الدنك النزفية

Re: Dengue Haemorrhagic Fever Presenting 
as Acute Abdomen

LETTER TO EDITOR