Vitamin A status of pre-school children in Ibadan (South West Nigeria), risk factors and comparison of methods of diagnosis.

Vitamin A deficiency (VAD) and protein energy malnutrition (PEM), sharing common aetiological factors, are important public health problems in many developing, countries. A cross-sectional survey of the vitamin A status of 128 well nourished and 230 malnourished pre-school children was carried out in order to define factors associated with increased risks of VAD and also to determine the predictive values of CIC-T in identifying serum retinol of < 10 microg/dl in these children. The proportional morbidity rates of VAD defined by serum retinol concentrations (7.3%) and CIC-T (6.2%) was similar (p>0.05), and children aged < 3 years accounted for 70% of VAD cases. VAD occurred in 6.3% and 7.8% of well-nourished and malnourished children respectively. The risk of VAD was increased following measles, history of persistent diarrhoea and wasting. The predictive value of CIC-T is highly dependent on CIC-T such that abnormal and normal smears classification appears to be very robust and predictive of serum retinol of < 10 microg/dl, with sensitivity of 83.3% (95%CI: 61.8-94.5), and specificity of 73.3% (95%CI: 68.3-78.5). Judging by the proportional morbidity rate in this study, VAD appears to be a significant public health problem in both malnourished and well-nourished Nigerian children, especially in children < 3 years of age. The history of measles and persistent diarrhoea appear to increase the risk of VAD. The simplicity, sensitivity and specificity of CIC-T suggest that this procedure is a good screening tool for epidemiological survey of vitamin A status.

Haemophilus influenzae type b meningitis in The Gambia after introduction of a conjugate vaccine.

After the introduction of a Haemophilus Influenzae type b (Hib) conjugate vaccine into The Gambia, the annual incidence of Hib meningitis has fallen from more than 200 per 100,000 before vaccination to 21 per 100,000 during the past 12 months.

PIP: This paper reports on the impact of Haemophilus influenzae type b (Hib) conjugate vaccine on the incidence of Hib meningitis in Gambia. The incidence of Hib meningitis among infants younger than 12 months of age in Gambia is greater, and the children affected are younger, compared to children in more developed countries. Between March 1993 and December 1995, children who were administered diphtheria-tetanus-pertussis (DTP) vaccination were randomly assigned a course of Hib conjugate vaccine mixed with DTP or DTP only. In Gambia, DTP vaccinations are recommended at 2, 3, and 4 months of age. The coverage of these vaccinations has been over 85% since 1990. Hib disease has not disappeared from Gambia in the last 2 years since the national immunization program was introduced. However, the incidence rate has declined rapidly, and a longer period of vaccination may be needed to achieve a sufficient herd effect to protect unimmunized children.

Conjunctival impression cytology with transfer in the assessment of vitamin A status in Nigerian children.

OBJECTIVE: To determine vitamin A status by conjunctival impression cytology with transfer (CIC-T) and assess its ability to predict low and deficient serum retinol concentrations. STUDY DESIGN: CIC-T was performed on 128 healthy, well-nourished and 230 malnourished children aged under 6 years by a 3-5-second application of cellulose acetate paper to each bulbar conjunctiva followed by transfer of the adhered cells onto glass slides. The slides were stained with Alcian green 2GX, and smears were classified as normal, borderline normal, borderline abnormal and deficient. Corresponding serum retinol levels were determined in each subject. RESULTS: The results showed that CIC-T is a simple procedure with a failure rate of 7.3% caused by tearing and agitation. The power of CIC-T to predict vitamin A status varied with both the CIC-T smear classification used and serum retinol concentration threshold. CIC-T smear classification as abnormal and normal appears to be the most robust and predictive of serum retinol, < 10 and > 10 < 20 micrograms/dL, respectively. CONCLUSION: The simplicity, sensitivity and specificity of CIC-T suggest that this procedure is a good screening tool for epidemiologic survey of vitamin A status.

Detection of Haemophilus influenzae and Streptococcus pneumoniae DNA in blood culture by a single PCR assay.

A multiplex PCR assay was developed to screen blood cultures from children in The Gambia with suspected pneumonia for the simultaneous detection of Haemophilus influenzae type b and Streptococcus pneumoniae isolates. Analysis of 295 blood cultures showed that PCR detected the organisms in all samples positive by culture in two samples infected with H. influenzae type b and four samples infected with S. pneumoniae that were culture negative, indicating that this method is sensitive for detecting these organisms in blood cultures.