Complement alternative pathway genetic variation and Dengue infection in the Thai population.

Dengue disease is a mosquito-borne infection caused by Dengue virus. Infection may be asymptomatic or variably manifest as mild Dengue fever (DF) to the most severe form, Dengue haemorrhagic fever (DHF). Mechanisms that influence disease severity are not understood. Complement, an integral component of the immune system, is activated during Dengue infection and the degree of activation increases with disease severity. Activation of the complement alternative pathway is influenced by polymorphisms within activation (factor B rs12614/rs641153, C3 rs2230199) and regulatory [complement factor H (CFH) rs800292] proteins, collectively termed a complotype. Here, we tested the hypothesis that the complotype influences disease severity during secondary Dengue infection. In addition to the complotype, we also assessed two other disease-associated CFH polymorphisms (rs1061170, rs3753394) and a structural polymorphism within the CFH protein family. We did not detect any significant association between the examined polymorphisms and Dengue infection severity in the Thai population. However, the minor allele frequencies of the factor B and C3 polymorphisms were less than 10%, so our study was not sufficiently powered to detect an association at these loci. We were also unable to detect a direct interaction between CFH and Dengue NS1 using both recombinant NS1 and DV2-infected culture supernatants. We conclude that the complotype does not influence secondary Dengue infection severity in the Thai population.

Dengue infection with central nervous system manifestations.

A prospective observational study was conducted over a seven years period to determine the clinical and laboratory findings of dengue patients with central nervous system manifestations. Thirty serologically confirmed dengue infected patients with central nervous system manifestations were seen at the Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok and at Songkhla Hospital, Songkhla, Thailand. The age ranged between 3 months and 14 years with a mean age of 6.2 years. Seventeen were boys and thirteen were girls. The central nervous system manifestations included alteration of consciousness 76.7%, seizures 63.3%, pyramidal tract signs 36.7%, meningeal signs 30% and headache 26.7%. Eleven patients had primary while 19 had secondary dengue infection. Cerebrospinal fluid examination showed lymphocytic pleocytosis in 6 out of 28 patients while presence of anti-dengue IgM antibodies was detected in 2 out of 19 specimens of cerebrospinal fluid tested. Two patients died, autopsy was done on one patient and examination of the brain was compatible with viral encephalitis.

Perinatal HIV infections in Thailand.

A collaborative study group of researchers from seven hospitals from all regions of Thailand was formed to collect information on children born to HIV-infected mothers since the beginning of the first hospital case until the end of June 1994. The study conducted to verify the status of perinatal transmission of HIV infection in Thailand showed a rapid increase in HIV seropositivity among Thai mothers with vertical transmission rates varying between 25% in Rayong and 42% in Chiang Rai Hospitals, respectively. The majority of children with symptomatic HIV infection had clinical presentations of delayed growth development, pneumonia, diarrhea, oral candidiasis, lymphadenopathy, hepato-splenomegaly. Cases of Penicillium marneffei infection were found only at Chiang Rai Prachanukroh Hospital. The ages at which diagnosis of HIV disease was made were mostly within the first year of life. One third of children with AIDS died during the period of study.