Indonesia has annually experienced approximately 100,000 reported cases of dengue fever (DF) and dengue hemorrhagic fever (DHF) in recent years. However, epidemiological surveys of dengue viruses (DENVs) have been limited in this country. In Surabaya, the second largest city, a single report indicated that dengue virus type 2 (DENV2) was the predominant circulating virus in 2003–2005. We conducted three surveys in Surabaya during: (i) April 2007, (ii) June 2008 to April 2009, and (iii) September 2009 to December 2010. A total of 231 isolates were obtained from dengue patients and examined by PCR typing. We found that the predominant DENV shifted from type 2 to type 1 between October and November 2008. Another survey using wild-caught mosquitoes in April 2009 confirmed that dengue type 1 virus (DENV1) was the predominant type in Surabaya. Phylogenetic analyses of the nucleotide sequences of the complete envelope gene of DENV1 indicated that all 22 selected isolates in the second survey belonged to genotype IV and all 17 selected isolates in the third survey belonged to genotype I, indicating a genotype shift between April and September 2009. Furthermore, in December 2010, isolates were grouped into a new clade of DENV1 genotype I, suggesting clade shift between September and December 2010. According to statistics reported by the Surabaya Health Office, the proportion of DHF cases among the total number of dengue cases increased about three times after the type shift in 2008. In addition, the subsequent genotype shift in 2009 was associated with the increased number of total dengue cases. This indicates the need for continuous surveillance of circulating viruses to predict the risk of DHF and DF.

SUMMARY: Dengue hemorrhagic fever (DHF) is a severe form of dengue fever (DF). Recent in vitro studies indicate that complement reduces the infection-enhancing activity of dengue antibodies, suggesting its in vivo role in controlling viremia levels and disease severity. In this study, the complement hemolytic activity (CH50) and levels of complement components and related factors in dengue patients in Indonesia were assessed. Based on the number of days since fever onset, DF patients were compared with patients at the DHF pre-critical phase who showed deterioration within 2 days. The mean CH50 values and levels of C2, C4, and factors B and H in the DHF pre-critical phase group were significantly lower than those in the DF group. The mean CH50 values were significantly correlated with C4, factor B, or factor H levels, indicating their responsibility for reduced CH50 values. Furthermore, a significantly higher proportion of the DHF pre-critical phase group (78z) than the DF group (33z) was positive for the nonstructural protein 1 (NS1) antigen. These results suggested that antibody-dependent enhancement of infection occurs during a period of low complement activity, which is associated with NS1 levels during the acute phase in some patients, thereby leading to increased viremia levels and greater disease severity.

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Latar belakang. Infeksi virus dengue sering menyerang anak rusia di bawah 15 tahun. Jumlah kasus cukup tinggi terdapat di Kabupaten Jombang, Jawa Timur. Pola jumlah trombosit, leukosit, dan hematokrit dapat berfungsi sebagai prediktot perjalanan penyakit pada kasus dengue.Tujuan. Untuk mengetahui perbedaan dan pola jumlah trombosit, leukosit serta hematokrit pada penderita DF (dengue fever) dan DHF (dengue hemorrhagic fever) guna memprediksi perjalanan penyakit.Metode. Penelitian ini menggunakan desain cross sectional pada anak yang telah terdiagnosis DF maupun DHF berdasarkan kriteria WHO 2011 dan menjalani perawatan di ruang rawat inap anak RS Kristen Mojowarno Kabupaten Jombang periode Februari-Juli 2019. Data jumlah trombosit, leukosit, hematokrit, suhu tubuh, hari sakit, dan karakteristik penderita diambil dari rekam medis kemudian dianalisis menggunakan independent sample T test dan Mann Whitney.Hasil. Selama kurun waktu penelitian terdapat 127 responden dengan rerata usia 6,67 tahun untuk kasus DF dan 6,43 tahun untuk DHF. Periode defervescent ditemukan pada hari ke-4 sakit. Rerata trombosit pasien DF dan DHF menurun di hari sakit ke-3 dan sangat rendah pada hari sakit ke-6. Rerata trombosit DHF berada di bawah 100.000 sel/mm3 sejak periode defervescent dengan rerata terendah mencapai 74.727 sel/mm3. Rerata leukosit DF dan DHF menurun sejak hari sakit ke-3 dan mencapai puncak penurunan pada periode defervescent. Rerata hematoktit DHF meningkat sejak hari sakit ke-3 dan mencapai puncaknya pada hari sakit ke-5. Terdapat perbedaan yang signifikan pada rerata hematokrit antara pasien DF dan DHF pada hari sakit ke-5 (p=0,004).Kesimpulan. Terdapat perbedaan yang bermakna signifikan pada rerata persentase hematokrit penderita DF dan DHF.