Seroepidemiology of enteric fever and brucellosis in a developing country.

The seroepidemiology of infection due to S. typhi and Brucella spp. in a sub-tropical, developing country of the Middle East was investigated in 130 children of age less than 1 to 15 years, 117 young adults (16-30 years) and in a further 40 adults (greater than 30 years) using an agglutination test to detect antibodies to of S. typhi, B. abortus and B. melitensis. Only 4.5% of the children's and adult's sera respectively showed the presence of antibodies to both O and H antigens of S. typhi with reciprocal titers greater than or equal to 80. Prevalence rates of 11.6%, 11.3% respectively in children and adults of antibodies to B. abortus with reciprocal titers greater than or equal to 80 and similarly 13.1%, 12.4% to B. melitensis were found. The usefulness of a single Widal test to diagnose enteric fever in a non-endemic area and the agglutination test in the diagnosis of brucellosis in an endemic area was investigated. Of 244 patients with suspected enteric fever, the sera of 100 showed reciprocal antibody titers 80 to both O and H antigens and included in these were 8 patients with concurrent culture positivity. Among 138 children and adults with suspected brucellosis, 29 culture proven cases where serologically confirmed and a further 90 were detected serologically. The sera of all the culture proven cases exhibited antibody reciprocal titer greater than or equal to 640. A similar antibody response was noted in seventy-two of the culture negative cases diagnosed serologically for brucellosis. In culture proven, cases B. melitensis was the isolate. Comparative evaluation indicated the potential usefulness of the Rose Bengal Antigen Slide Agglutination Test (Brucelloside Test) as a screening test in the serodiagnosis of human brucellosis.

Chlamydia trachomatis as a cause of abortion.

The possible role of C. trachomatis as a causative agent of abortion in humans was investigated using the tissue culture method for the isolation of chlamydia. Two cases of spontaneous abortion and another seven of recurrent abortion due to C. trachomatis were positively identified. Among those with recurrent abortion were four patients with history of second trimester abortion.

Viral meningitis and encephalitis in Saudi Arabia.

The laboratory confirmation of twelve clinically diagnosed cases of aseptic meningitis and encephalitis is described. Among three cases of aseptic meningitis one was due to mumps in a 14-month infant and the other two attributable to Cocksackie B-1. Herpes virus encephalitis due to HSV-1 was conclusively identified by IF monoclonal test from brain biopsy in tissue culture, and a further four cases also of HSV-1 encephalitis by virus isolation from CSF and presence of significant levels of herpes virus antibody in CSF and serum. Measles encephalitis was identified in four pediatric patients with one based on the isolation of measles virus from the CSF and in the other three with significant CSF/serum ratios to measles virus.

Genital herpes simplex virus infections: laboratory confirmation in diverse patient groups.

The laboratory diagnosis of genital herpes simplex virus (HSV) infections in various patient groups with diverse clinical manifestations including asymptomatic pregnant women with history of genital herpes and in a high prevalence group consisting of male patients with recurring genital ulcerations is described. HSV was detected by conventional cell culture and also by a CPE-enhancement technique using human embryonic lung fibroblasts (MRC-5) and Vero cells with subsequent typing of isolate by HSV type-specific monoclonal antibodies. A definite improvement in HSV diagnosis was noted by the use of the CPE-enhancement technique with the reduction of turn-around time to 24 h at which 61.1% and 50% isolation rates were detected in MRC-5 cells in comparison to 38.9% and 16.6% by conventional cell culture in the high prevalence patient population and asymptomatic pregnant women, respectively. Delayed development of CPE and reduced isolation rates were detected using Vero cells. Follow-up sampling of subsequent episodes of genital ulcerations in those with history of recurrence but an initial negative cell culture result, increased the isolation rate substantially and enabled the confirmation of diagnosis of genital HSV infection.

Tonsillitis and respiratory infections of viral aetiology in a developing country.

Among 75 clinically diagnosed cases of tonsillitis, 55 (73.3%) were found to be of viral aetiology. Serological and virological investigations identified adenovirus as the main causative agent in children as well as in adults. In only two instances, both in children, was an association with respiratory syncytial virus (RSV) in tonsillitis detected, an extremely rare finding. A cross-sectional sero-epidemiological study of respiratory infections caused by adenovirus, RSV, influenza (A,B) and para-influenza (types 1,2,3) viruses was carried out in 289 Saudi children (newborn to 15 years of age) and 86 adults (healthy male blood donors and pregnant women) using a single serological technique. In children as well as in adults, adenoviruses were the most predominant respiratory pathogens, with no marked variation in age-specific antibody prevalence rates.