Christy An Okoromah

Pre-vaccination nasopharyngeal pneumococcal carriage in a Nigerian population: epidemiology and population biology.

Background Introduction of pneumococcal vaccines in Nigeria is a priority as part of the Accelerated Vaccine Introduction Initiative (AVI) of the Global Alliance for Vaccines and Immunisation (GAVI). However, country data on the burden of pneumococcal disease (IPD) is limited and coverage by available conjugate vaccines is unknown. This study was carried out to describe the pre vaccination epidemiology and population biology of pneumococcal carriage in Nigeria. Methods This was a cross sectional survey. Nasopharyngeal swabs (NPS) were obtained from a population sample in 14 contiguous peri-urban Nigerian communities. Data on demographic characteristics and risk factor for carriage were obtained from all study participants. Pneumococci isolated from NPS were characterised by serotyping, antimicrobial susceptibility and Multi Locus Sequencing Typing (MLST). Results The prevalence of pneumococcal carriage was 52.5%. Carriage was higher in children compared to adults (67.4% vs. 26%), highest (≈90%) in infants aged <9 months and reduced significantly with increasing age (P<0.001). Serotypes 19F (18.6%) and 6A (14.4%) were most predominant. Potential vaccine coverage was 43.8%, 45.0% and 62% for PCV-7, PCV-10 and PCV-13 respectively. There were 16 novel alleles, 72 different sequence types (STs) from the isolates and 3 Sequence Types (280, 310 and 5543) were associated with isolates of more than one serotype indicative of serotype switching. Antimicrobial resistance was high for cotrimoxazole (93%) and tetracycline (84%), a third of isolates had intermediate resistance to penicillin. Young age was the only risk factor significantly associated with carriage. Conclusions Pneumococcal carriage and serotype diversity is highly prevalent in Nigeria especially in infants. Based on the coverage of serotypes in this study, PCV-13 is the obvious choice to reduce disease burden and prevalence of drug resistant pneumococci. However, its use will require careful monitoring. Our findings provide sound baseline data for impact assessment following vaccine introduction in Nigeria.

Prevalence, profile and predictors of malnutrition in children with congenital heart defects: a case–control observational study

Objective To investigate the prevalence, profile and predictors of severe malnutrition in children with congenital heart defects (CHDs). Design Case–control, observational study. Setting Tertiary teaching hospital in Lagos, Nigeria (March 2006 to March 2008). Participants Children aged 3–192 months with uncorrected symptomatic CHD and healthy controls, frequency matched for age and sex. Main outcome measures Prevalence of malnutrition based on WHO/National Center for Health Statistics/Centers for Disease Control and Prevention z score ≤−2; weight for age, weight for height/length and height for age; proportions of underweight, wasting and stunting in cases and controls, and in acyanotic and cyanotic CHD; and predictors of malnutrition using multivariate logistic analysis. Results 90.4% of cases and 21.1% of controls had malnutrition (p=0.0001), and 61.2% and 2.6%, respectively, had severe malnutrition (p=0.0001). Wasting, stunting and underweight were identified in 41.1%, 28.8% and 20.5%, and 2.6%, 3.9% and 14.5% of cases and controls, respectively. Wasting was significantly higher (58.3%) in acyanotic CHD (p=0.0001), and stunting (68.0%) in cyanotic CHD (p=0.0001). Age at weaning was significantly lower in cases than controls (3.24±0.88 and 7.04±3.04 months, respectively; p=0.0001) and in acyanotic than cyanotic CHD (2.14±0.33 and 5.33±1.22 months, respectively; p=0.004). Predictors of malnutrition in CHD were anaemia, moderate to severe congestive heart failure (CHF), poor dietary intake of fat and prolonged unoperated disease. Conclusion Severe malnutrition in association with anaemia and moderate to severe CHF is highly prevalent in CHD preoperatively in these children. Early weaning may be a marker of feeding difficulties in heart failure.

Serum Cardiac Troponin T in Asphyxiated Term Neonates Delivered at Two Teaching Hospitals in Lagos, Nigeria

Background: Asphyxia is a leading cause of perinatal morbidity and mortality in the developing countries. All organs including the myocardium are vulnerable to ischemic injury in asphyxia. The aim of the current study was to assess myocardial injury in asphyxiated full-term neonates using their serum cardiac troponin T levels. Methods: In all, 30 term asphyxiated neonates and 30 gestational age-, birth weight-, and sex-matched controls were studied. Asphyxia was defined by double criteria of low umbilical arterial blood pH <7.20 and low five-minutes Apgar score ≤6, while the controls were term nonasphyxiated neonates with umbilical arterial blood pH ≥7.20 and five minutes Apgar score >6. The umbilical arterial pH was done soon after delivery, while the serum cardiac troponin T was done within the first 4 to 24 hours of life. Results: Participants and controls were similar in terms of mean gestational age, mode of delivery, gender, and birth weight (P = 1.0, .07, 1.0, and 1.0, respectively). Two thirds of the asphyxiated babies had elevated serum cardiac troponin T in the high risk range (> 0.1 ng/mL). On the contrary, none of the controls had serum cardiac troponin T in that range. Serum cardiac troponin T showed negative correlation with pH (r = −.75), five-minute Apgar score (r = −.74), and one-minute Apgar score (r = −0.70). Conclusion: The study identified perinatal asphyxia as a high-risk factor for elevated serum cardiac troponin T and hence for myocardial cellular injury.

Pulmonary hypertension among 5 to 18 year old children with sickle cell anaemia in Nigeria.

Background Pulmonary hypertension (PHT) is a significant cause of mortality in patients with sickle cell disease (SCD). Few studies on PHT in SCD have been carried out in children. This study aimed to estimate the prevalence of PHT in children with sickle cell anaemia (SCA) and determine its clinical and laboratory correlates. Methods In this cross sectional study, evaluation involved obtaining bio-data, history and physical examination findings in 175 SCA subjects with haemoglobin genotype SS aged 5 to 18 years and 175 age and sex matched controls with haemoglobin genotype AA. PHT was determined using peak Tricuspid Regurgitant Velocity (TRV) obtained from echocardiography as a marker. Complete blood count (CBC), lactate dehydrogenase (LDH) assay, reticulocyte count, foetal haemoglobin (HbF) estimation as well as Human Immunodeficiency Virus (HIV) I and II, Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) screening were done for patients with SCA. Results The mean peak TRV of subjects with SCA and controls was 2.2 ± 0.4 m/s and 1.9 ± 0.3 m/s respectively and prevalence of PHT among children with SCA and controls was 22.9% and 2.3% respectively. PHT in SCA correlated negatively with body mass index, haematocrit and haemoglobin. Conclusion This study affirms that PHT prevalence is high in children with SCA in Nigeria. Cardiovascular examination for signs of PHT is recommended for children with SCA and if required, further echocardiographic assessment from as early as five years.