Dengue Infection in Children in Ratchaburi, Thailand: A Cohort Study. II. Clinical Manifestations

Dengue infection is one of the most important diseases transmitted to human by mosquito bite. The disease may be mild or severe. This study reveals the occurrence and clinical features of diseases caused by dengue infection in a 3-year follow-up in school-children aged 3–14 years in Ratchaburi Province, Thailand using an active surveillance for the episodes of fever. Children who had fever were laboratory tested for the evidence of dengue infection and recorded for clinical features. It was found that most of dengue infected patients had headache, anorexia, nausea/vomiting, and muscle ache. About half of the patients had clinical symptoms that closely mimic other diseases, especially respiratory tract infection, and were incorrectly diagnosed by pediatricians. Only 11% of the patients had more a severe disease called “dengue hemorrhagic fever.” This severe disease may be predicted by the presence of anorexia, nausea/vomiting, and abdominal pain after the second day of illness. This study provides better understanding in this disease

Number of serological confirmed dengue cases from January to December in 2006–2009.

<p>Number of serological confirmed dengue cases from January to December in 2006–2009.</p

The prevalence (%) of clinical manifestation of dengue diseases from previous studies.

<p>ND = no data.</p>a<p>include both myalgia and arthralgia.</p

Dengue incidence.

<p>(<b>A</b>) Shown is the incidence by school in each year. (<b>B</b>) Shown is the incidence by school in all years.</p

The prevalence of common symptoms in dengue infection by the day of illness.

<p>The prevalence of common symptoms in dengue infection by the day of illness.</p

Symptoms and disease severity from different dengue serotypes [n (%)].

<p>Symptoms and disease severity from different dengue serotypes [n (%)].</p

Symptoms of dengue infection [n (%)].

a<p>significantly more common in DHF compared to DF and UF, but no difference between UF and DF.</p>b<p>significantly less common in UF compared to DF and DHF, but no difference between DF and DHF.</p>c<p>significantly more common in DHF compared to DF and UF, and more common in DF compared to UF.</p

Dengue Infection in Children in Ratchaburi, Thailand: A Cohort Study. I. Epidemiology of Symptomatic Acute Dengue Infection in Children, 2006–2009

<div><h3>Background</h3><p>There is an urgent need to field test dengue vaccines to determine their role in the control of the disease. Our aims were to study dengue epidemiology and prepare the site for a dengue vaccine efficacy trial.</p> <h3>Methods and Findings</h3><p>We performed a prospective cohort study of children in primary schools in central Thailand from 2006 through 2009. We assessed the epidemiology of dengue by active fever surveillance for acute febrile illness as detected by school absenteeism and telephone contact of parents, and dengue diagnostic testing. Dengue accounted for 394 (6.74%) of the 5,842 febrile cases identified in 2882, 3104, 2717 and 2312 student person-years over the four years, respectively. Dengue incidence was 1.77% in 2006, 3.58% in 2007, 5.74% in 2008 and 3.29% in 2009. Mean dengue incidence over the 4 years was 3.6%. Dengue virus (DENV) types were determined in 333 (84.5%) of positive specimens; DENV serotype 1 (DENV-1) was the most common (43%), followed by DENV-2 (29%), DENV-3 (20%) and DENV-4 (8%). Disease severity ranged from dengue hemorrhagic fever (DHF) in 42 (10.5%) cases, dengue fever (DF) in 142 (35.5%) cases and undifferentiated fever (UF) in 210 (52.5%) cases. All four DENV serotypes were involved in all disease severity. A majority of cases had secondary DENV infection, 95% in DHF, 88.7% in DF and 81.9% in UF. Two DHF (0.5%) cases had primary DENV-3 infection.</p> <h3>Conclusion</h3><p>The results illustrate the high incidence of dengue with all four DENV serotypes in primary school children, with approximately 50% of disease manifesting as mild clinical symptoms of UF, not meeting the 1997 WHO criteria for dengue. Severe disease (DHF) occurred in one tenth of cases. Data of this type are required for clinical trials to evaluate the efficacy of dengue vaccines in large scale clinical trials.</p> </div

Occurrence of selected clinical manifestations [n/total] and their predictive value (%) for DHF among dengue infected cases.

<p>Occurrence of selected clinical manifestations [n/total] and their predictive value (%) for DHF among dengue infected cases.</p

The number of dengue infected patients who had prolonged symptom (for 3 or more days) [n (%)].

<p>NA = not applicable.</p>a<p>significantly more common in DHF compared to DF and UF, but no difference between DF and UF.</p>b<p>significantly less common in UF compared to DF and DHF, but no difference between DF and DHF.</p>c<p>significantly more common in UF compared to DF and DHF, but no difference between DF and DHF.</p>d<p>significantly less common in DF compared to UF and DHF, but no difference between UF and DHF.</p