A molecular dynamics study on the thermal properties of carbon-based gold nanoparticles

Due to unique features in surface activity, thermal stability, electrical and thermal conductivity, and compatibility with biomolecules such as DNA and proteins, carbon-based nanoparticles are raised potential as a candidate for various applications such as catalytic processes, drug delivery, light, and electrical engineering. Based on this premise, thermodynamic features of pure, graphene, and carbon nanotube (CNT)-based gold nanoparticles (AuNPs) are investigated using molecular dynamics approach. Melting, heat capacity, thermal conductivity, contact angle of molten AuNPs, and phase transition are calculated as indicators of thermodynamic properties of pure and carbon-based AuNPs. Simulation results indicate that the presence of a carbon platform and its contact surface area has a significant role in the thermodynamic properties of AuNPs and leads the phononic heat capacity and thermal conductivity to decrease for AuNPs. The platform also causes the melting point temperature of AuNPs to increase. The melting of gold on the carbon base is of the first-order type. In addition, contact angle for molten AuNPs on the Graphene is significantly higher than the one on the CNT due to more contact area on the Graphene substrate.Graphical abstract .

A novel optical model of the experimental transmission spectra of nanocomposite PVC-PS hybrid thin films doped with silica nanoparticles

We propose a novel derived optical model fitted to the experimental transmittance of PVC-PS hybrid thin films doped with Silica nanoparticles. The films are synthesized using a simple dip-coating method. The model has successfully interpreted the experimental spectral behaviour of transmittance of amorphous semiconductors and dielectric thin films. Interestingly, our model reproduces the optical parameters of the investigated thin films in good agreement with those predicted by Tauc plot. The great advantage of the proposed model over other models lies in its ability to explain the correlations between the film thickness and the optical bandgap. Furthermore, we investigate the structural, physical, and optical properties of PVC-PS- SiO₂ thin films, in relevance to the silica percentage content. XRD measurements show that the as-prepared polymeric thin films are amorphous. In addition, SEM micrographs indicate that silica nanoparticles are well dispersed on the surface of the PVC-PS thin films with an average diameter of 100-400 nm. The effect of annealing parameters is also investigated to optimize the projected water contact angle of PVC-PS- SiO₂ thin films. At annealing temperature of 2000°C, films become hydrophobic. The transmittance T% of the PVC-PS thin films is found to be about 83% in the visible region. The T% enhances to 90% upon adding silica NPs into PVC-PS polymeric thin films. Obtaining coatings with high transmittance is of crucial importance for several optoelectronic and photonic applications.

Development and evaluation of a loop-mediated isothermal amplification (LAMP) assay for the detection of the E198A SNP in the isotype-1 β-tubulin gene of Haemonchus contortus populations in China

Haemonchus contortus is one of the most important gastrointestinal nematodes of small ruminants around the world, seriously hampering the healthy development of the sheep industry. The control of this parasite mainly depends on anthelmintics, however, drug resistance of H. contortus has become a serious problems worldwide. Previous studies demonstrated that the E198A (GAA to GCA), a single nucleotide polymorphism (SNP) in the isotype-1 β-tubulin gene is associated with benzimidazole resistance in H. contortus. However, only PCR-RFLP and ARMS-PCR methods have been previously used for the detection of the E198A mutation. In the present study, a loop-mediated isothermal amplification (LAMP) assay was established for rapid detection of the E198A SNP in H. contortus. The results showed that optimization of LAMP reaction reagents and conditions could achieve this. The resulting amplicons were visualized by adding hydroxynaphthol blue dye (HNB) prior to amplification. The color of LAMP products amplified without DNA or from DNA from worms with the E198A homozygous susceptible genotype was still violet, but the products with DNA from worms with the E198A heterozygous genotype or the E198A resistant homozygous genotype changed to sky blue. The specificity of this method was further verified by sequencing, which confirmed the successful LAMP detection of the E198A mutation with high specificity. In conclusion, the developed LAMP method has high specificity and good reproducibility for screening the E198A SNP of isotype-1 β-tubulin gene of H. contortus of field samples without using sophisticated equipment, providing useful technique for the rapid detection and thus prevention and control of benzimidazole resistant H. contortus infections.

Total quality management in the health-care context: integrating the literature and directing future research

Background

Synergistic integration of predictors and elements that determine the success of total quality management (TQM) implementations in hospitals has been the bane of theoretical development in the TQM research area. Thus, this paper aims to offer a systematic literature review to provide a foundation on which research on TQM can be built and to identify the predictors of successful TQM in the health-care context.

Materials and methods

A systematic literature survey was adopted in this paper, involving the review of 25 relevant researched articles found in the databases Science Direct, EBSCO, MEDLINE, CINAHL and PubMed.

Result

The systematic literature survey reveals five variables to be core predictors of TQM, signifying how important these variables are in the successful implementation of TQM in the health-care context. Also, it is revealed that the identified core predictors have positive effects on an improved health-care system. However, the systematic survey of the literature reveals a dearth of studies on TQM in the health-care context.

Conclusion

As TQM has become an important management approach for advancing effectiveness in the health-care sector, this kind of research is of value to researchers and managers. Stakeholders in the health sectors should introduce and implement TQM in hospitals and clinics. Nevertheless, this study has limitations, including that the databases and search engines adopted for the literature search are not exhaustive.

Characterization of the Complete Mitochondrial Genome of a Whipworm Trichuris skrjabini (Nematoda: Trichuridae)

The complete mitochondrial (mt) genome of Trichuris skrjabini has been determined in the current study and subsequently compared with closely related species by phylogenetic analysis based on concatenated datasets of mt amino acid sequences. The whole mt genome of T. skrjabini is circular and 14,011 bp in length. It consists of a total of 37 genes including 13 protein coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNAs) genes, and two non-coding regions. The gene arrangement and contents were consistent with other members of the Trichuridae family including Trichuris suis, Trichuris trichiura, Trichuris ovis, and Trichuris discolor. Phylogenetic analysis based on concatenated datasets of amino acids of the 12 PCGs predicted the distinctiveness of Trichuris skrjabini as compared to other members of the Trichuridae family. Overall, our study supports the hypothesis that T. skrjabini is a distinct species. The provision of molecular data of whole mt genome of T. skrjabini delivers novel genetic markers for future studies of diagnostics, systematics, population genetics, and molecular epidemiology of T. skrjabini.

Characterization of the Complete Mitochondrial Genome of Ostertagia trifurcata of Small Ruminants and its Phylogenetic Associations for the Trichostrongyloidea Superfamily

The complete mitochondrial (mt) genome of Ostertagia trifurcata, a parasitic nematode of small ruminants, has been sequenced and its phylogenetic relationship with selected members from the superfamily Trichostrongyloidea was investigated on the basis of deduced datasets of mt amino acid sequences. The entire mt genome of Ostertagia trifurcata is circular and 14,151 bp in length. It consists of a total of 36 genes comprising 12 genes coding for proteins (PCGs), 2 genes for ribosomal RNA (rRNA), 22 transfer RNA (tRNA) genes and 2 non-coding regions, since all genes are transcribed in the same direction. The phylogenetic analysis based on the concatenated datasets of predicted amino acid sequences of the 12 protein coding genes supported monophylies of the Haemonchidae, Dictyocaulidae and Molineidae families, but rejected monophylies of the Trichostrongylidae family. The complete characterization and provision of the mtDNA sequence of Ostertagia trifurcata provides novel genetic markers for molecular epidemiological investigations, systematics, diagnostics and population genetics of Ostertagia trifurcata and its correspondents.

Estimating the scale of chronic hepatitis C virus infection in the EU/EEA: a focus on migrants from anti-HCV endemic countries

Background

Increasing the proportion diagnosed with and on treatment for chronic hepatitis C (CHC) is key to the elimination of hepatitis C in Europe. This study contributes to secondary prevention planning in the European Union/European Economic Area (EU/EEA) by estimating the number of CHC (anti-HCV positive and viraemic) cases among migrants living in the EU/EEA and born in endemic countries, defining the most affected migrant populations, and assessing whether country of birth prevalence is a reliable proxy for migrant prevalence.

Methods

Migrant country of birth and population size extracted from statistical databases and anti-HCV prevalence in countries of birth and in EU/EEA countries derived from a systematic literature search were used to estimate caseload among and most affected migrants. Reliability of country of birth prevalence as a proxy for migrant prevalence was assessed via a systematic literature search.

Results

Approximately 11% of the EU/EEA adult population is foreign-born, 79% of whom were born in endemic (anti-HCV prevalence ≥1%) countries. Anti-HCV/CHC prevalence in migrants from endemic countries residing in the EU/EEA is estimated at 2.3%/1.6%, corresponding to ~580,000 CHC infections or 14% of the CHC disease burden in the EU/EEA.

The highest number of cases is found among migrants from Romania and Russia (50–60,000 cases each) and migrants from Italy, Morocco, Pakistan, Poland and Ukraine (25–35,000 cases each). Ten studies reporting prevalence in migrants in Europe were identified; in seven of these estimates, prevalence was comparable with the country of birth prevalence and in three estimates it was lower.

Discussion

Migrants are disproportionately affected by CHC, account for a considerable number of CHC infections in EU/EEA countries, and are an important population for targeted case finding and treatment. Limited data suggest that country of birth prevalence can be used as a proxy for the prevalence in migrants.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12879-017-2908-5) contains supplementary material, which is available to authorized users.

Multi-organ Metastasis of Fibrolamellar Hepatocellular Carcinoma in a Malayan Gharial (Tomistoma schlegelii)

A 38-year-old Malayan gharial (Tomistoma schlegelii) with a 2-week history of anorexia was found dead and presented for post-mortem examination. Numerous white firm nodules of various sizes were found on the surface of the liver, both left and right kidneys, the spleen and the serosa of the intestinal tract. All masses had similar microscopical appearance and were diagnosed as metastasizing fibrolamellar hepatocellular carcinoma. Immunohistochemically, the tumour cells did not react with antibodies specific for pan-cytokeratin, vimentin or HepPar-1. The anti-HepPar-1 and anti-pan-cytokeratin antibodies also did not react with normal hepatocytes or exocrine pancreatic cells. This is the first description of fibrolamellar hepatocellular carcinoma with metastases in a crocodilian.

Temperature Affects Aggressiveness and Fungicide Sensitivity of Four Pythium spp. that Cause Soybean and Corn Damping Off in Iowa

Damping off of soybean and corn, caused by Pythium spp., is favored by cool temperatures and wet soil conditions and is primarily managed using fungicide seed treatments. The goal of this research was to determine the effect of temperature on aggressiveness and fungicide sensitivity of Pythium spp. recovered from soybean and corn in Iowa. A total of 21 isolates of four of the most prevalent Pythium spp. in Iowa were screened. Seed and seedling assays were used to quantify the aggressiveness of P. lutarium, P. oopapillum, P. sylvaticum, and P. torulosum on soybean and corn at 13, 18, and 23°C. Isolates recovered from soybean or corn were equally pathogenic on both hosts. P. torulosum was more aggressive at 13°C compared with 18 and 23°C. Conversely, P. sylvaticum was more aggressive at 18 and 23°C than at 13°C. A plate assay was used to assess fungicide sensitivity to seven fungicides that are commonly used as seed treatments, and EC₅₀ values at each of the three temperatures were determined and compared. EC₅₀ values for P. torulosum were higher for all fungicides tested at 13°C, compared with 18 or 23°C, whereas EC₅₀ values for P. sylvaticum were higher for all fungicides at 18 and 23°C compared with 13°C. These data contribute to our understanding of the effect of soil temperature on the risk of soybean and corn damping off, which may aid in the development of more effective management practices.

The correlation of Helicobacter Pylori with the development of cholelithiasis and cholecystitis: the results of a prospective clinical study in Saudi Arabia

OBJECTIVE

Gallstone disease is a common surgical ailment. Helicobacter pylori has a role in upper gastrointestinal disorders, including gallstones. This study aimed to determine the association of H. pylori with gallstones, so developing a preventative strategy for gallstone formations.

PATIENTS AND METHODS

A prospective study was conducted on 95 patients referred to the surgical clinic of Al-Meeqat General Hospital, Al-Madinah Al-Munawarah, with gallstone disease. Detection of H. pylori antibodies (IgG) in serum was done in all the patients who underwent cholecystectomy. H. pylori stool antigen (HPSA) using stool samples was done for IgG sero-positive patients prior to the cholecystectomy. The bile collected from the gall bladder during operation was examined for the presence of H. pylori by Gram stain, culture and HPSA assay. Gallbladder mucosa was examined for urease A gene by polymerase chain reaction (PCR) in patients proven to be positive for stool or bile serology.

RESULTS

Of the 95 patients, 75 (79%) were positive for H. pylori antibodies. Twenty-six (34.7%) patients were positive with H. pylori antigens in bile and 21 (28%) with H. pylori antigens in the stool samples. Among these 47 patients, PCR was positive in 29 (62%) subjects. H. pylori couldn't be detected among the studied patients by using either Gram stain or culture.

CONCLUSIONS

The presence of H. pylori in bile may indicate a significant risk for cholelithiasis. PCR is a rapid reliable method for the detection of H. pylori DNA in bile. This rapid molecular approach together with culture and immunological methods could help clinicians to effectively manage patients at high risk of developing gallstones at an earlier stage.

First Report of Pythium schmitthenneri Causing Maize Seedling Blight in Iowa

In spring 2012, maize farmers in southeast and south central Iowa reported stand losses due to pre- and post-emergence damping-off, and many of the fields had to be replanted. Symptoms of the disease included rotted seed, or brown, rotted, water-soaked mesocotyls and root tips. Maize seedlings with severe root and mesocotyl symptoms were yellow and wilted, stunted, or dead. The disease occurred approximately 2 weeks after cool, wet conditions. Symptomatic mesocotyls and roots were washed for 30 min, rinsed with sterile distilled water, and blotted dry on sterile paper towels. Isolation of the pathogen was performed by aseptically cutting 2- to 3-mm sections of tissue from the edge of a lesion, placing the segments under corn meal agar (CMA) containing pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene (PARP), and incubating at 22°C in the dark. Colonies that developed were putatively identified as Pythium species based on morphological characteristics and cultural features when compared to published descriptions (2,3). Characteristics of isolate IAC12F21-3 included spherical and smooth-walled oogonia 18 to 26 μm in diameter, monoclinous or usually diclinous antheridia 10 to 22 μm long and 5 to 10 μm wide with one or occasionally two per oogonium, and plerotic oospores 15 to 25 μm in diameter. Sporangia were globose to ellipsoidal, 22 to 41 μm in diameter, and zoospores were 7 to 10 μm long. Primers ITS1 and ITS4 were used to amplify the ITS region within clade E1 of 88 isolates. The resultant amplicons were sequenced and a BLAST search in GenBank confirmed isolate IAC12F21-3 as Pythium schmitthenneri based on 100% similarity with GenBank accession numbers JF836869 and JF836870. Pathogenicity testing was conducted using seed and seedling assays (1,4). Koch's postulates was performed by sampling pieces of symptomatic mesocotyl and root tissue from the inoculated pots, placing segments under CMA + PARP, and incubating at 22°C. Symptoms were similar to those observed in the field and P. schmitthenneri was re-isolated successfully. Non-inoculated control plants showed no symptoms. This is the first report of P. schmitthenneri causing seedling blight on maize in Iowa. Previously, P. schmitthenneri was reported as a pathogen on maize in Ohio (2). References: (1) K. Broders et al. Plant Dis. 91:727, 2007. (2) M. Ellis et al. Mycologia, 104:477, 2012. (3) J. Middleton. Memoirs of the Torrey Botanical Club 20:171, 1943. (4) A. Rojas et al. Phytopathology, 102(Suppl):S5.8, 2012.

Malaysian and Thai smokers' beliefs about the harmfulness of 'light' and menthol cigarettes

OBJECTIVE

This study explored the extent to which Malaysian and Thai smokers believe "light" and menthol cigarettes are less harmful than "regular" cigarettes and the correlates of these beliefs.

METHODS

The study used data from wave 1 of the International Tobacco Control Southeast Asia Survey. 2006 adult smokers (95.3% male) from Malaysia and 2000 adult smokers (94.5% male) from Thailand were interviewed face to face in 2005.

RESULTS

29% of Malaysian respondents reported currently smoking light cigarettes and 14% menthols, with 19% agreeing that lights are less harmful and 16% agreeing that menthols are less harmful. 38% of Thai respondents reported currently smoking light cigarettes and 19% menthols, with 46% agreeing that lights are less harmful and 35% agreeing that menthols are less harmful. Malaysian smokers reporting current use of light or menthol cigarettes were more likely to believe that they are less harmful. Reported use of lights did not relate to beliefs for Thai respondents. The belief that light and/or menthol cigarettes are less harmful was strongly related to the belief that they have smoother smoke.

CONCLUSIONS

The experience of smoother smoke is likely to produce some level of belief in reduced harm, regardless of how brands are labelled and whether or not Federal Trade Commission FTC/International Organisation for Standardisation tar, nicotine and carbon monoxide yield figures are used.

Fixed-bed adsorption of reactive azo dye onto granular activated carbon prepared from waste

In this work, the adsorption potential of bamboo waste based granular activated carbon (BGAC) to remove C.I. Reactive Black (RB5) from aqueous solution was investigated using fixed-bed adsorption column. The effects of inlet RB5 concentration (50-200mg/L), feed flow rate (10-30 mL/min) and activated carbon bed height (40-80 mm) on the breakthrough characteristics of the adsorption system were determined. The highest bed capacity of 39.02 mg/g was obtained using 100mg/L inlet dye concentration, 80 mm bed height and 10 mL/min flow rate. The adsorption data were fitted to three well-established fixed-bed adsorption models namely, Adam's-Bohart, Thomas and Yoon-Nelson models. The results fitted well to the Thomas and Yoon-Nelson models with coefficients of correlation R(2)>or=0.93 at different conditions. The BGAC was shown to be suitable adsorbent for adsorption of RB5 using fixed-bed adsorption column.

Effect of preparation conditions of activated carbon from bamboo waste for real textile wastewater

This study deals with the use of activated carbon prepared from bamboo waste (BMAC), as an adsorbent for the removal of chemical oxygen demand (COD) and color of cotton textile mill wastewater. Bamboo waste was used to prepare activated carbon by chemical activation using phosphoric acid (H(3)PO(4)) as chemical agent. The effects of three preparation variables activation temperature, activation time and H(3)PO(4):precursor (wt%) impregnation ratio on the color and COD removal were investigated. Based on the central composite design (CCD) and quadratic models were developed to correlate the preparation variables to the color and COD. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The optimum condition was obtained by using temperature of 556 degrees C, activation time of 2.33 h and chemical impregnation ratio of 5.24, which resulted in 93.08% of color and 73.98% of COD.

Reduction of COD and color of dyeing effluent from a cotton textile mill by adsorption onto bamboo-based activated carbon

In this work, activated carbon was prepared from bamboo waste by chemical activation method using phosphoric acid as activating agent. The activated carbon was evaluated for chemical oxygen demand (COD) and color reduction of a real textile mill effluent. A maximum reduction in color and COD of 91.84% and 75.21%, respectively was achieved. As a result, the standard B discharge limit of color and COD under the Malaysian Environmental Quality act 1974 was met. The Freundlich isotherm model was found best to describe the obtained equilibrium adsorption data at 30 degrees C. The Brunauer-Emmett-Teller (BET) surface area, total pore volume and the average pore diameter were 988.23 m(2)/g, 0.69 cm(3)/g and 2.82 nm, respectively. Various functional groups on the prepared bamboo activated carbon (BAC) were determined from the FTIR results.

Removal of disperse dye from aqueous solution using waste-derived activated carbon: optimization study

The purpose of this work is to obtain optimal preparation conditions for activated carbons prepared from rattan sawdust (RSAC) for removal of disperse dye from aqueous solution. The RSAC was prepared by chemical activation with phosphoric acid using response surface methodology (RSM). RSM based on a three-variable central composite design was used to determine the effect of activation temperature (400-600 degrees C), activation time (1-3h) and H(3)PO(4):precursor (wt%) impregnation ratio (3:1-6:1) on C.I. Disperse Orange 30 (DO30) percentage removal and activated carbon yield were investigated. Based on the central composite design, quadratic model was developed to correlate the preparation variables to the two responses. The most influential factor on each experimental design responses was identified from the analysis of variance (ANOVA). The optimum conditions for preparation of RSAC, which were based on response surface and contour plots, were found as follows: temperature of 470 degrees C, activation time of 2h and 14min and chemical impregnation ratio of 4.45.

Batch adsorption of methylene blue from aqueous solution by garlic peel, an agricultural waste biomass

The potential of garlic peel (GP), agricultural waste, to remove methylene blue (MB) from aqueous solution was evaluated in a batch process. Experiments were carried out as function of contact time, initial concentration (25-200mg/L), pH (4-12) and temperature (303, 313 and 323 K). Adsorption isotherms were modeled with the Langmuir, Freundlich, and Temkin isotherms. The data fitted well with the Freundlich isotherm. The maximum monolayer adsorption capacities were found to be 82.64, 123.45, and 142.86 mg/g at 303, 313, and 323 K, respectively. The kinetic data were analyzed using pseudo-first-order and pseudo-second-order models. The results indicated that the garlic peel could be an alternative for more costly adsorbents used for dye removal.

Epidemiology of rotavirus infection in north-western Nigeria

Rotaviruses (RV) are associated with approximately 33 000 deaths in children <5 years of age annually in Nigeria. However, limited data exit on RV infection in north-western Nigeria. During July 2002 to July 2004, 1063 (869 diarrhoeic and 194 control) stool samples were collected from children <5 years of age presenting with diarrhoea in north-western Nigeria. The stools were analysed for RV antigen and further characterized by antigenic and genomic methods. RV was detected in 18% of children with diarrhoea and 7.2% of the age-matched case controls. The highest RV burden was detected in children <6-months-old. Long electropherotypes and VP6 subgroup I + II specificity predominated.

Adsorption of direct dye on palm ash: kinetic and equilibrium modeling

Palm ash, an agriculture waste residue from palm-oil industry in Malaysia, was investigated as a replacement for the current expensive methods of removing direct blue 71 dye from an aqueous solution. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Equilibrium data fitted well with Freundlich model in the range of 50-600mg/L. The equilibrium adsorption capacity of the palm ash was determined with the Langmuir equation and found to be 400.01mg dye per gram adsorbent at 30 degrees C. The rates of adsorption were found to conform to the pseudo-second-order kinetics with good correlation. The results indicate that the palm ash could be employed as a low-cost alternative to commercial activated carbon.

Effect of sickle cell trait and B-Thalassemia minor on determinations of HbA1c by an immunoassay method

OBJECTIVE

Glycated hemoglobin determination is being used worldwide to monitor the efficiency of blood glucose control and to plan treatment in diabetes mellitus patients. Several methods are used for measuring glycated hemoglobin, but a possible interference by hemoglobin variants is a major concern. The use of immunoassay methods with glycated hemoglobin-specific antibodies is supposed to overcome this problem. We are evaluating the effect of the most prevalent hemoglobinopathies in the region (sickle trait hemoglobin and B-Thalassemia) on the immunoassay method used in determining glycated hemoglobin.

METHODS

Eighty-one whole blood sample hemolysates were tested for glycated hemoglobin using Beckman Synchron LX20 system, 37 of these normal adult hemoglobin represented 22 diabetic and 15 non-diabetic samples. Of the remaining 44 samples, 28 were from B-thalassemia minor and 16 from sickle-cell trait sickle trait hemoglobin patients, all non-diabetic. The samples were collected in ethylenediaminetetraacetic acid anticoagulant and analyzed immediately or stored at 4?C for not more than 2 days.

RESULTS

Sickle trait hemoglobin had no effect on glycated hemoglobin measurement by Synchron LX20 while B-thalassemia minor blood elevated the value of glycated hemoglobin to the range of diabetic cases.

CONCLUSION

Synchron LX20 glycated hemoglobin immunoassay method gave falsely high glycated hemoglobin results with B-thalassemia minor patient samples. Therefore, while interpreting the results of Synchron LX20 glycated hemoglobin, the patients history regarding hemoglobinopathies should be checked.

Influence of climatic factors on rotavirus infection among children with acute gastroenteritis in Zaria, northern Nigeria

Stool samples from 392 infants and young children attending various clinics in Zaria, Northern Nigeria from June 1986 to May 1987 were analysed by ELISA for the presence of rotaviruses. There was a prevalence of 27 per cent in these children with the virus being most prevalent in the first 6 months of life. This decreased with age until it was less than 10 per cent in children 3-5 years old. Although rotavirus was found to be present throughout the year; there was a much higher prevalence during the dry season (October to April) as compared to the wet season. Infection with the virus correlated inversely with relative humidity, vapour pressure and minimum temperature showing considerable influence of these climatic factors on rotavirus infection in children in Zaria.

Prevalence of Mycoplasma pneumoniae in children with pneumonia in Zaria, Nigeria

The prevalence of Mycoplasma pneumoniae in children suffering from pneumonia was investigated, using complement fixation and growth inhibition tests. From the sera of 104 children with pneumonia, 32 (31%) showed a CF titre greater or equal to 1:64, while all the 52 control children of the same age and sex had a CF titre less than 1:16. Children 6-10 years of age had the highest positive titre (41%) while the age groups 3-5 years and 0-2 years had positive titres of 30 and 28%, respectively. Both sexes were equally affected (33% male, 29% female). Mycoplasma pneumoniae was isolated in two children whose CF antibody titres were 1:16. It is concluded that M. pneumoniae plays an important role as an aetiological agent of pneumonia in children in Zaria, Nigeria, and could be included in the routine diagnostic protocol of pneumonia, especially during the dry harmattan months when cases of lobar pneumonia are prevalent.

Prevalence of rubella antibodies on the African continent

Until recently, data on the epidemiology of rubella in Africa have been very scarce. However, several seroepidemiologic surveys within the last 10 years show that the virus is prevalent throughout Africa. In most of Africa rubella is contracted early in life; in areas such as the Gambia, Egypt, Zimbabwe, Mali, and parts of Kenya greater than 80% of children are immune to the virus by 10 years of age, and this level increases through adulthood. Most studies show that greater than 80% of pregnant women are immune to rubella.

The levels of measles antibodies in Nigerian children aged 0-12 months and its relationship with maternal parity

Six hundred and fifty-seven children aged between 0 and 12 months were randomly chosen and studied for measles antibody titres by the haemagglutination inhibition (HAI) test. The results showed significant variations in HAI antibody titres. Children between 0-3 months showed high measles HAI antibody titres which declined to a trough between 4 and 6 months. A rise in HAI antibody titre was observed from 10 to 12 months age. Multiparity and higher age in the mothers were noted as probable factors influencing the titres of measles HAI antibody in children. The results indicated that with increased maternal parity, measles HAI antibody titres in the children declined.