Rapid diagnosis and determination of duration of viraemia in dengue fever using a reverse transcriptase polymerase chain reaction

A rapid, simple diagnostic polymerase chain reaction (PCR) method for the diagnosis of dengue fever was developed using a pair of consensus oligonucleotide primers and validated with laboratory-derived strains of dengue serotypes 1-4 and other common flaviviruses. A cluster of 13 patients with clinical dengue fever admitted to a single infectious diseases unit over a period of 3 months allowed evaluation of this technology. The PCR was positive in all 11 acute dengue cases and negative in 2 convalescent cases and 10 febrile patients recently returned from the tropics in whom an alternative diagnosis was established. In some of the acute cases, viraemia was detected before the development of a diagnostic antibody response (indirect immunoglobulin (Ig) G enzyme-linked immunosorbent assay (ELISA) and capture IgM ELISA). In patients from whom sequential sera were taken, defervescence and recovery from thrombocytopenia coincided with the disappearance of dengue ribonucleic acid from the blood. Nucleotide sequencing of the PCR products was undertaken in 2 cases (from India and Guyana) and the results showed a close match with previously reported serotype 2 sequencies, suggesting a potential for use of this region of the genome in epidemiological studies.

Prevalence of HIV-1 in east African lorry drivers

Sixty-eight lorry drivers and their assistants were examined for evidence of infection with HIV-1 because of their association and regular contact with prostitutes. Out of a total of 68 drivers, 24 (35.2%) were serologically found to be HIV-1 positive. Epidemiological evidence demonstrated a wide travel history involving seven different countries served by the port of Mombasa. History of other sexually transmitted disorders were significantly higher in HIV-seropositive individuals. The data presented here further support the hypothesis that a major route of heterosexual transmission of HIV in Africa is dissemination through a group such as lorry drivers and their assistants, whose behaviour puts them at risk of acquiring sexually transmitted diseases.