Malaria prevalence and associated risk factors in Eritrea

A parasitological cross-sectional survey was undertaken from September 2000 through February 2001 to estimate the prevalence of malaria parasitemia in Eritrea. A total of 12,937 individuals from 176 villages were screened for both Plasmodium falciparum and Plasmodium vivax parasite species using the OptiMal Rapid Diagnostic Test. Malaria prevalence was generally low but highly focal and variable with the proportion of parasitemia at 2.2% (range: 0.4% to 6.5%). Despite no significant differences in age or sex-specific prevalence rates, 7% of households accounted for the positive cases and 90% of these were P. falciparum. Multivariate regression analyses revealed that mud walls were positively associated with malaria infection (OR [odds ratio] = 1.6 [95% CI: 1.2, 2.2], P < 0.008). For countries with low and seasonal malaria transmission, such information can help programs design improved strategic interventions.     

Pulmonary function indices in children with sickle cell anemia in Enugu,south-east Nigeria

Objectives:

To determine the pulmonary function indices of children with sickle cell anemia (SCA) attending the pediatric sickle cell clinic at the University of Nigeria Teaching Hospital, Enugu, south-east Nigeria and to compare these indices with the results obtained from other regions.

Methods:

A case control study of lung function in children with SCA aged 6-20 years. The study was carried out in the University of Nigeria/University of Nigeria Teaching Hospital, Enugu State, Nigeria between October 2014 and January 2015. Measurements of the peak expiratory flow rate, forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) were evaluated.

Results:

A total of 80 subjects were recruited into the study, comprising 40 homozygous HbSS (hemoglobin SS) patients and an equal number of controls. Children with SCA had statistically lower values of FEV1 (1.6±0.52), FVC (1.76±0.95), and peak expiratory flow rate (PEFR) (309.00±82.64) when compared with normal hemoglobin genotype FEV1 (12.01±0.53), FVC (2.12±0.54), and PEFR (364.10±87.85). The mean FVC, FEV1/FVC, and PEFR were also higher in the male control group compared with the HbSS male group, but these differences were not statistically significant. Female controls had significantly larger FEV1, FVC, and PEFR values compared with the HbSS females.

Conclusion:

The lung function indices were significantly lower in children and adolescents with SCA compared with the matched controls with a hemoglobin genotype AA.Sickle cell anemia (SCA) is a genetic hematological disorder characterized by red blood cells that assume an abnormal, rigid, sickle shape.1 This hereditary disorder contributes the equivalent of 3.4% mortality in children aged <5 years worldwide or 6.4% in Africa.2 The prevalence of SCA in Nigeria ranges from 0.4-3%.3 Approximately 85% of sickle cell disorders and >70% of all affected births occur in Africa.4 It is worth noting that at least 5.2% of the world population carry a significant trait. The clinical consequence of SCA results from obstruction of the microvasculature by the sickle cells and red blood cell hemolysis, which causes multi-systemic manifestation. The lungs are affected in a variety of ways by these pulmonary insults, and recurrence overtime may leave the lungs with chronic interstitial, parenchymal, or vascular damage that compromises pulmonary function.5,6 It has been documented that the prevalence of hypoxemia among SCA children was 13%.4 This prevalence was attributable to the chronic anemic state, micro vascular occlusion of the circulation by sickle hemoglobin, and constant pertubation of the endothelial membrane, and consequent elaboration of endothelial molecules, which are commonly seen among SCA children, especially those with various types of vaso-occlusive episodes.7 This is defined as bone and joint pain or multiple sites of pain needing analgesics or hospitalization.8 Acute and chronic pulmonary complications occur frequently in patients with SCA, and contribute to morbidity and mortality later in life. Although the pathogenesis of chronic pulmonary disease in sickle cell disease (SCD) has not been clearly defined, recurrent microvascular obstruction resulting in the development of pulmonary hypertension, endothelial dysfunction, and parenchymal fibrosis are probably the primary mechanisms.6 There is increasing evidence that repeated episodes of acute chest syndrome (ACS) may cause permanent damage to the pulmonary parenchyma and vasculature. Repeated attacks of ACS are a major risk factor for the development of sickle cell chronic lung disease. Studies of lung function in SCD have also demonstrated a restrictive defect,8,9 while a reduction in the total lung capacity (TLC) of 50% has been reported in advanced forms. Acute chest syndrome refers to a spectrum of pulmonary pathology having in common, chest pain, fever, dyspnea with abnormal clinical, and radiologic chest signs as well as leucocytosis.10,11 It is the most common cause of death in children with sickle cell anemia over 10 years of age.12 The etiology of ACS is not clear, lung and bone infarction, infection, and acute pulmonary sequestration, among other possible causes have been proposed.10 In children with sickle anemia in steady state, the major abnormality in pulmonary function is a restrictive pathology, characterized by a slight decrease in total lung capacity, with attendant ventilation perfusion mismatch.10 This can cause a defect in diffusion capacity for carbon monoxide.10 These abnormalities worsen with age and are associated with increases in pulmonary-artery pressures.11 Whereas some studies have documented impaired lung function in SCA (hemoglobin SS) patients,8-10 previous studies8-10 reported what appears to be contrasting findings when the lung function in children with SCA and those of healthy controls with normal hemoglobin genotype were compared. It is therefore necessary that ventilatory function studies be undertaken in this parts of the world to see if there is any difference with known values in other part of the world. In this study, we determine the impact of SCA on the pulmonary function indices in patients attending the pediatric sickle cell clinic at the University of Nigeria Teaching Hospital (UNTH) Enugu, south-east Nigeria and compare it with matched controls and other studies. Many studies have described and assessed the pattern of pulmonary function in SCD from childhood to adulthood, but much is not known on this topic in South Eastern Nigeria. Most of the original studies are from western Nigeria.13,14 This study could therefore corroborate or refute regional or ethnic differences in lung function in children with SCD. The study hypothesis seeks to answer the following questions? Do children with SCA attending UNTH Enugu present with any alteration in lung function? If they do, is there any gender and age difference? Are these lung volume findings similar to that obtained from other region?     

Towards eradicating antibiotic-resistant bacteria: synthesis and antibacterial activities of substituted N-(2-nitrophenyl)pyrrolidine- and piperidine-2-carboxylic acids

Antibacterial resistance is a source of great concern in the effective prevention and treatment of infections caused by bacteria, making the development of requisite therapeutics a major challenge. N-(Nitrophenyl)cycloamino acids are important compounds in the synthesis of poly-condensed nitrogen-containing heterocycles with marked activities in many biological systems. A series of substituted N-(o-nitrophenyl)cycloamino-2-carboxylic acids 3a–3g were synthesized via the condensation reaction of substituted o-halogenonitrobenzenes with L-proline 2a and D,L-pipecolinic acid 2b, under refluxing alcoholic basic conditions in excellent yields. The synthesized compounds were characterised by FT-IR, (¹H & ¹³C) NMR, UV-Vis, mass spectroscopy and elemental analysis. Their antibacterial activities were evaluated against five Gram-positive and five Gram-negative bacterial strains using the broth micro-dilution procedure. The antibacterial activities of the synthesized compounds were compared with streptomycin and nalidixic acid as standard antibiotic drugs. The minimum inhibitory concentration (MIC) values of compounds 3a–3g revealed good antibacterial activities against the tested microorganisms. Compounds 3a–3g were more potent than nalidixic acid against Enterococcus faecalis, Mycobacterium smegmatis, Escherichia coli and Proteus vulgaris and also more potent than streptomycin against Enterobacter cloacae and Staphylococcus aureus. Compounds 3a, 3c and 3g displayed the highest antibacterial potency with an MIC value of 15.6 μg/mL against E. cloacae, E. faecalis and P. mirabilis, respectively. These results indicated that these aryl cycloamino acids with antibacterial activities had potential applications as substitutes for antimicrobial peptide antibiotics, which are not susceptible to bacterial resistance, to solve the problem of drug resistance.     

Isolation and biological characterization of non-B HIV type 1 from Kenya

The isolation and characterization of primary strains of human immunodeficiency virus (HIV) is a vital tool for assessing properties of viruses replicating in HIV-infected subjects. HIV-1 isolation was carried out from 30 HIV-1-infected patients from a Comprehensive Care Clinic (CCC) after informed consent. Virus was successfully isolated from 9 out of the 30 samples investigated. Seven of the isolates were from drug-naive patients while two were from patients on antiretroviral drugs. The isolates were biologically phenotyped through measurement of the syncytium-inducing capacity in MT2 cells. Six of the isolates exhibited syncytia induction (SI) associated with CXCR4 coreceptor usage while three of the isolates were non-syncytia-inducing (NSI) isolates associated with CCR5 coreceptor usage. In addition, the replication capacity of the isolates was further determined in established cell line CD4(+) C8166. Indirect immunofluorescence assay was used to check the antigen expression on the cells as a supplementary test. HIV-1 isolation success was 70% (7/10) and 20% (2/20) in naive and drug-experienced patients, respectively. The majority of the viral isolates obtained (6/9) were of the SI phenotype, though SI virus strains are rare among non-B subtypes. A significant correlation between virus isolation success and viral load was established. Coreceptor use data for heavily treatment-experienced patients with limited treatment options are scanty and this is the group with perhaps the most urgent need of novel antiretroviral agents.     

Clinical algorithms for malaria diagnosis lack utility among people of different age groups

We conducted a study to determine whether clinical algorithms would be useful in malaria diagnosis among people living in an area of moderate malaria transmission within Kilifi District in Kenya. A total of 1602 people of all age groups participated. We took smears and recorded clinical signs and symptoms (prompted or spontaneous) of all those presenting to the study clinic with a history of fever. A malaria case was defined as a person presenting to the clinic with a history of fever and concurrent parasitaemia. A set of clinical signs and symptoms (algorithms) with the highest sensitivity and specificity for diagnosing a malaria case was selected for the age groups /=15 years. These age-optimized derived algorithms were able to identify about 66% of the cases among those <15 years of age but only 23% of cases among adults. Were these algorithms to be used as a basis for a decision on treatment among those presenting to the clinic, 16% of children /=5000 parasites/microl of blood would be sent home without treatment. Clinical algorithms therefore appear to have little utility in malaria diagnosis, performing even worse in the older age groups, where avoiding unnecessary use of anti-malarials would make more drugs available to the really needy population of children under 5 years of age.