Epidemiology of Clinical Isolates of Mycobacterium tuberculosis at Ibadan, Nigeria

Despite the huge burden of tuberculosis (TB) in Nigeria, case detection rate of infectious cases still remain low, thus constituting obstacle to eradication of the disease in the community. We carried out a 15 month (1st January 2008 to 30th March 2009) retrospective review of epidemiology of clinical isolates of M. tuberculosis isolated at TB regional reference laboratory at the department of Medical Microbiology and Parasitology, University College Hospital, Ibadan, Nigeria. Fifty isolates were recovered from 720 specimens during the period of study with a recovery rate of 6.9%. Sixty- two (8.6%) of the specimens were contaminated. Thirty eight (76.0%) isolates were from the specimens of male subjects and 12 (24.0%) from female subjects giving a male to female ratio of 3.2: 1.0 Majority (62.0%) of the isolates were from subjects aged 20 years and above with an isolation rate of 7.3% while only two clinical isolates (4.0%) were recovered from specimens from children. A high yield of 20.8% was recovered from specimen collected from Hausa ethnic group who predominantly domiciled in a particular part of the metropolis. In terms of socio-economic status, clinical isolates recovered from specimens from unskilled workers (76.0%) was more than thrice from that obtained from the professionals (24.0%). Seven (14.0%) of the total isolates were recovered from extra-pulmonary lesions while the majority 43 (86.0%) were for pulmonary TB. The isolation rate from children and extra-pulmonary sites are low. This suggests a need to pay more attention to diagnosis of childhood and extra-pulmonary TB in Ibadan, Nigeria.Keywords: M. tuberculosis, Isolates, Epidemiology, Ibadan.     

The genetic diversity of Mycobacterium tuberculosis and an assessment of risk factors of tuberculosis spread in Russia's Siberian region by molecular epidemiological methods

Molecular epidemiology approaches provided for a new interpretation of the TB infection transmission dynamics, contributed to changing the focuses of attention and updated the monitoring practice. On the basis of 101 cases of isolates of Mycobacterium tuberculosis (MBT) complex sampled from 84 patients with pulmonary tuberculosis in the Siberian region, we proved that the independent methods of IS6110 RFLP genetic typing and VNTR-typing by five accurate repeat tandems of ETR A, B, C, D, and E bring about similar results and can be used in studying the MTB clonal structure population in the Siberian region for the purpose of defining the TB infection transmission dynamics. The most widespread genetic types were detected, i.e. Beeijing family strains, the S42 spoligotype, and the 31323 VNTR type, which account for 52.3% of all samples. The general parameters describing the epidemic process intensity were evaluated, i.e. those characterizing the strains (91.6%) and the transmission activity factor (72%). Consequently, each three of the four analyzed TB cases resulted from a recent transmission. However, there is a trend, within the analyzed samples, towards a higher percentage of clusterization in the age group ranging from 40 to 60. Such trend is typical of a prevalence of TB reactivation cases caused by MBT complex strains spread intensively in the discussed territory. As for the clusterized isolates, which are endemic for the territory, such data should be interpreted as a recent transmission only cautiously. 28.5% of the studied isolates are resistant to anti-TB drugs used in medical practice; and 35.7% of them are resistant to izoniazide and rifampicin, therefore, according to the WHO classification they are considered to be poly-antibiotics-resistant (PAR). No strict associations were found between the spectrum of antibiotics-resistance and any of genotypes, however, 30% of PAR strains are 32525 and 42525 types VNTR (spoligotype S1 or Beejing type).     

A Study of Environmental Awareness and Attitudes in Ibadan,Nigeria

Biodiversity and the natural environment have suffered a huge negative impact around the world as a result of excessive exploitation by humans and the often short-sighted economic policies of national governments. Some scientists have asserted that the resolution of this problem may lie in a proper examination and understanding of human knowledge of, and attitudes toward, the environment. In this study, we examine the distribution of environmental awareness and attitudes in Ibadan, south-western Nigeria across sociodemographic categories. We found that contrary to a number of findings from studies in other parts of the world, older respondents were the most concerned about the environment and youths were not more knowledgeable than older individuals about environmental issues. Male respondents had more knowledge than females but gender did not affect other aspects of environmental attitudes. However, occupation and education both had marked effects on environmental knowledge and attitudes. Our study suggests that given the current socioeconomic situation in Nigeria, and limited knowledge of environmental issues, the most effective strategy for promoting environmentally responsible behavior and positive attitudes regarding less obvious issues such as biodiversity loss might simply be to increase exposure to straightforward messages emphasizing their relevance.     

Hydrology and Plankton of Eleiyele Reservoir Ibadan,Nigeria

Summary This study describes seasonal variation in the numbers of planktonic organisms in relation to hydrological changes in a flood-controlled reservoir at Ibadan, Nigeria. Results of fortnightly estimations of water-level, temperature, transparency, and oxygen content have been presented. The reservoir is thermally stratified for most of the year but the periodic flooding following heavy rainfall and the occasional breakdown of the periodic flooding following heavy rainfall and the occasional breakdown of the thermal stratification by winds during the dry season dominate the habitat, causing regular seasonal fluctuation in plant nutrients and the transparency of the water.Such effects have also been shown to exert an important influence directly on the zooplankton as well as on the phytoplankton. The highest plankton densities were recorded during periods of maximum water level and the lowest during the beginning of the filling process. Some evidence suggests that the zooplankton feeds directly on bacteria-rich detritus and that the phytoplankton probably plays an insignificant part as food source for the zooplankton. The phytoplankton may be controlled primarily by the limitation and decline of plant nutrients from the reservoir bed.

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Résumé Etude concernant les variations de la quantité de plancton en rapport avec les changements de l'eau dans un reservoir a Ibadan (Nigéria). Les résultats des mensurations bimensuelles du niveau de l'eau, de sa température et de sa transparence ont été étudiés. L'auteur a fait une stratification thermale pour une grande partie de l'année, mais l'inondation périodique qui suit chaque grande précipitation ainsi que la perturbation occasionelle de la stratification thermale efectuée par les vents pendant la saison sèche, dominent le milieu et occasionnent des variations régulières dans la quantité des plantes nutritives et dans la transparence de l'eau.Ces phénomènes ont une grande influence directe sur le zooplancton aussi bien que sur le phytoplancton. Les densités les plus considérables de plancton sont enrégistrées pendant la saison où le niveau de l'eau est au maximum et les plus basses au début de la saison d'inondation. Les résultats montrent que le zooplancton se nourrit du détritus très riche en bactéries et que le phytoplancton ne joue qu'un rôle insignifiant comme source de nourriture pour le zooplancton. On peut d'ordinaire contrôler le phytoplancton par la limitation et la diminution des plantes nutritives dan le lit du réservoir.

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This is part of the material present for a Ph.D. Thesis of the University of London.     

On the phytoplankton of Awba reservoir, Ibadan, Nigeria

The physico-chemical characteristics and phytoplankton of Awba reservoir in the University of Ibadan, Nigeria, were monitored to determine the impact of eutrophication on phytoplankton composition. The principal component analysis identified three major components influencing the physicochemistry of the water, namely trace metals, dissolved oxygen and ionic composition. Comparative analysis with a previous study showed a phenomenal increase in zinc, copper and iron levels over a 10-year period. Furthermore, the ferruginous nature of the soil contributed to the high levels of iron which exceeded the World Health Organization Standards for drinking water quality. The most abundant phytoplankton species was Microcystis aeruginosa which has been implicated in toxic blooms in freshwaters. The conditions favouring cyanophyte blooms and their implications are discussed.     

Airborne pollen and fungal spores in Garki,Abuja (North-Central Nigeria)

The ambient atmosphere is dominated with pollen and spores, which trigger allergic reactions and diseases and impact negatively on human health. A survey of pollen and fungal spores constituents of the atmosphere of Garki, Abuja (North-Central Nigeria) was carried out for 1 year (June 1, 2011–May 31, 2012). The aim of the study was to determine the prevalence and abundance of pollen and fungal spores in the atmosphere and their relationship with meteorological parameters. Airborne samples were trapped using modified Tauber-like pollen trap, and the recipient solutions were subjected to acetolysis. Results revealed the abundance of fungal spores, pollen, fern spores, algal cysts and diatoms in decreasing order of dominance. The atmosphere was qualitatively and quantitatively dominated by pollen during the period of late rainy/harmattan season than the rainy season. Numerous fungal spores were trapped throughout the sampling periods among which Alternaria spp., Fusarium spp., Cladosporium spp. and Curvularia spp. dominated. These fungi have been implicated in allergic diseases and are dermatophytic, causing diverse skin diseases. Other pathogenic fungi found in the studied aeroflora were Dreschlera spp., Helminthosporium spp., Torula spp., Pithomyces spp., Tetraploa spp., Nigrospora ssp., Spadicoides spp., Puccinia spp. and Erysiphe graminis. Total pollen and fungal spores counts do not show significant correlation with meteorological parameters.     

结核分枝杆菌进化与致病性的研究

分子流行病学是研究结核分枝杆菌传播和种群进化的有力工具。特别是近年来建立起来的单核苷酸多态性分型方法,能将结核分枝杆菌临床菌株分为三大家族,并且确立其种系发生关系。研究表明,不同进化分支上的结核分枝杆菌在不同的国家和地区流行,不同基因型菌株的致病性和传播力不尽相同。如细胞和动物模型都证明在东亚流行的北京基因型菌株比其他基因型菌株具有更高的毒力,能抑制宿主的免疫反应。本文综述近年来在结核分枝杆菌进化、分型及菌株致病性方面的研究成果。     

Epidemiology of intestinal helminth parasites of dogs in Ibadan, Nigeria

An epidemiological study of gastrointestinal helminths of dogs (Canis familiaris) in two veterinary clinics in Ibadan, Nigeria, was conducted between January 2001 and December 2002. Faecal samples collected from 959 dogs were processed by modified Kato-Katz technique and then examined for helminth eggs. The results of the study showed that 237 (24.7%) of the dogs examined were infected with different types of helminths. The prevalences for the various helminth eggs observed were: Toxocara canis 9.0%, Ancylostoma spp. 17.9%, Toxascaris leonina 0.6%, Trichuris vulpis 0.5%, Uncinaria stenocephala 0.4% and Dipylidium caninum 0.2%. The faecal egg intensities, determined as mean egg count/gram of faeces ( +/- SEM), were: T. canis 462.0 +/- 100.5, Ancylostoma spp. 54.1 +/- 8.6, T. leonina 0.8 +/- 0.4, T. vulpis 0.1 +/- 0.0, U. stenocephala 1.0 +/- 0.7 and D. caninum 0.2 +/- 0.1. Host age was found to be a significant factor with respect to the prevalence and intensity of T. canis and Ancylostoma spp. There was no significant difference in the prevalence of intestinal helminth parasites between male (27.0%) and female (22.5%) dogs (P>0.05). The prevalence of helminth parasites was significantly higher (P < 0.05) in the local breed (African shepherd) (41.2%) than in Alsatian dogs (16.2%) or in other exotic breeds (21.0%). Single parasite infections (85.7%) were more common than mixed infections (3.5%).     

遗传多样性的分子检测

生物多样性的保护和可持续利用是维持全球经济稳定和发展的重要因素,也是保持我们赖以生存环境的重要内容。为了实现这一目的,必须尽快建立一套对生物多样性认识和检测的有效方法,逐步认清全球生物多样性的基本状况。本文论述了生物多样性特别是物种间和物种内多样性的几种主要检测方法,着重介绍分子标记的最新进展及比较基因组学的兴起在生物多样性研究中的广泛应用。     

A molecular epidemiological study of var gene diversity to characterize the reservoir of Plasmodium falciparum in humans in Africa

Background

The reservoir of Plasmodium infection in humans has traditionally been defined by blood slide positivity. This study was designed to characterize the local reservoir of infection in relation to the diverse var genes that encode the major surface antigen of Plasmodium falciparum blood stages and underlie the parasite''s ability to establish chronic infection and transmit from human to mosquito.

Methodology/Principal Findings

We investigated the molecular epidemiology of the var multigene family at local sites in Gabon, Senegal and Kenya which differ in parasite prevalence and transmission intensity. 1839 distinct var gene types were defined by sequencing DBLα domains in the three sites. Only 76 (4.1%) var types were found in more than one population indicating spatial heterogeneity in var types across the African continent. The majority of var types appeared only once in the population sample. Non-parametric statistical estimators predict in each population at minimum five to seven thousand distinct var types. Similar diversity of var types was seen in sites with different parasite prevalences.

Conclusions/Significance

Var population genomics provides new insights into the epidemiology of P. falciparum in Africa where malaria has never been conquered. In particular, we have described the extensive reservoir of infection in local African sites and discovered a unique var population structure that can facilitate superinfection through minimal overlap in var repertoires among parasite genomes. Our findings show that var typing as a molecular surveillance system defines the extent of genetic complexity in the reservoir of infection to complement measures of malaria prevalence. The observed small scale spatial diversity of var genes suggests that var genetics could greatly inform current malaria mapping approaches and predict complex malaria population dynamics due to the import of var types to areas where no widespread pre-existing immunity in the population exists.     

Roadside Topsoil Concentrations of Lead and Other Heavy Metals in Ibadan,Nigeria

Concentrations of Pb, Zn, Cd, Cu, Cr, Co, and Ni were determined in roadside topsoil collected from locations of varied vehicular traffic densities in the city of Ibadan, Nigeria, with a view to determining the level of contamination and the contribution of traffic density. Levels of Pb, Zn, Cd, and Cu were elevated above background concentrations measured in control areas. Average values (ppm) for all sample locations were Pb — 81±140; Zn — 48±37; Cd — 0.55±0.49; Cu — 17±17; Cr — 22.1±9.6; Co — 7.9±3.8; Ni — 10.5±9.7. Factors of accumulation of metals in roadsides relative to control sites were highest for Pb. Vehicular traffic was not an important source of chromium, cobalt and nickel, for which roadside concentrations were about those of the control sites. Metal concentrations were poorly correlated with traffic volumes. An average of about 60% of total soil concentration of the metals were determined to be held in bioavailable geochemical phases, of which the highest concentrations were mostly held in either the reducible or oxidizable phase. Levels of the metals in the topsoil were generally lower than the soil quality criteria of some developed countries.     

Pattern of tooth loss in an elderly population from Ibadan, Nigeria

Objectives: To determine tooth loss, edentulousness, causes of tooth loss and pattern of tooth loss in the elderly in South East Local Government area (SELGA) in Ibadan. Background data: SELGA is one of the largest in Oyo State, Nigeria and has a population of 225 800. Design: A cross‐sectional survey. Methodology: A total of 690 elderly individuals who were 65 years and above living in various wards in SELGA were interviewed by two interviewers and examined by two trained and calibrated examiners whilst two record clerks recorded all the findings of the examination. Result: Forty‐eight per cent of the subjects in the study had not lost any teeth. The mean tooth loss was 4.5 ± 7.6. Percentage edentulousness was 1.3% and this was higher in males than in females. This difference was not statistically significant (χ² = 0.07 p = 0.7). The total number of teeth lost was 3102, 14% of the total number of teeth examined. The study showed that caries was not a major cause of tooth loss. Only 22 (0.7%) teeth were lost as a result of caries, 19 (0.6%) were lost because of trauma and periodontal disease contributed to loss of 3061 (98.7%) teeth. Mandibular teeth exhibited a higher rate of retention than maxillary teeth. The percentage of elderly individuals with tooth loss increased with age. Conclusion: The study highlights the high life expectancy of a tooth among the elderly in SELGA. Despite the different cause of tooth loss in this area, in comparison with developed countries, the pattern of tooth retention appeared similar.     

Knowledge of possible pregnancy at first coitus: a study of in-school adolescents in Ibadan, Nigeria

This paper discusses the reproductive health knowledge of Nigerian in-school adolescents, with special reference to pregnancy occurrence at first coitus. The data were derived from an Association for Reproductive and Family Health (ARFH) survey carried out in four secondary schools in Ibadan, Nigeria, between August and October 1995. A total of 828 students were interviewed. The results revealed that the majority of sexually active adolescents were not aware of the consequences of their actions. Religious affiliation and number of wives in a male adolescent's family, and religion and marital status of a female adolescent's parents, were found to influence adolescents' knowledge of pregnancy probability at first coitus. This paper confirms earlier findings that the majority of Nigerian adolescents do not know the consequences of sex. Therefore, a clear-cut plan of action is needed to inform sexually active adolescents through an effective sex education programme.     

Salmonellae isolated from captive animals in Ibadan, Western State of Nigeria

Six serotypes of salmonellae, Salmonella offa, S. glostrup, S. wimborne, S. dublin, S. saint-paul and S. webridge were isolated from captive wild animals in Ibadan, Western State of Nigeria. S. wimborne and S. glostrup are reported for the first time in Nigeria. All strains were sensitive to nitrofurantoin (200 mcg) and chloramphenical (10 mcg) but there wasmarked resistance to sulphafurazole (100 mcg) and penicillin (1.5 units).     

Antibiograms of pathogenic bacteria isolated from laboratory rabbits in Ibadan, Nigeria

Antibiotic sensitivity patterns of 21 bacterial isolates from some clinically ill New Zealand rabbits were evaluated against 12 commonly used antibiotics by the Kirby-Bauer disk-diffusion sensitivity testing method. The 21 isolates consisted of six Bordetella bronchiseptica, eight Pasteurella multocida, four Staphylococcus aureus and three Pseudomonas alcaligenes that were associated with snuffles, pneumonia, otitis media, genital infections and conjunctivitis in these groups of caged rabbits. The four bacteria species were all sensitive to kanamycin, gentamycin and enrofloxacin, with variable sensitivity to the other antibiotics tested. The results of this antibiogram could serve as a field guide in the treatment of very acute bacterial diseases of rabbit prior to the availability of the results of local sensitivity tests. Such sensitivity tests should be reviewed yearly to update this antibiogram.     

Hereditary deafness in Kirov oblast: A genetic epidemiological study

The results of a genetic epidemiological study of hereditary deafness (HD) in ten raions (districts) of Kirov oblast (administrative region), Russia, are presented. A total of 122 075 people have been examined. Segregation analysis of all families with diagnosed HD has demonstrated a good fit to either the autosomal dominant (AD) or autosomal recessive (AR) mode of inheritance. The total prevalence rates of AD and AR HDs, as well as the specific prevalence rates of nonsyndromic and syndromic forms of HD, have been calculated for the population of ten raions. The HD prevalence rate in Kirov oblast has been found to be 1: 1043 people (1: 1453 and 1: 3699 for the nonsyndromic and syndromic forms, respectively). This value has been found to vary in different raions, which is explained by differences in the genetic subdivision levels of the populations studied; the correlation coefficient between the HD load and random inbreeding (F _ST) in district populations is r = 0.81 ± 0.22. The diversity of syndromic hearing disorders is described.     

Insecticide susceptibility of Anopheles coluzzii and Anopheles gambiae mosquitoes in Ibadan,Southwest Nigeria

The emergence of insecticide resistance in Anopheles (Diptera: Culicidae) mosquitoes has great implications for malaria control in Nigeria. This study aimed to determine the dynamics of insecticide susceptibility levels and the frequency of knock‐down resistance (kdr) mutations (L1014F) in wild Anopheles coluzzii Coetzee & Wilkerson sp. n. and Anopheles gambiae Giles from the Ojoo and Bodija areas of Ibadan, in southwest Nigeria. Insecticide susceptibility to pyrethroids, organophosphates, carbamates and organochlorines was assessed using World Health Organization (WHO) bioassays. A subset of the mosquitoes exposed to pyrethroids and DDT was used for species and molecular form identification; kdr genotyping was determined using the TaqMan real‐time polymerase chain reaction assay. The mosquitoes were resistant to pyrethroids and DDT but completely susceptible to organophosphates and carbamates. Bodija samples (n = 186) consisted of An. gambiae (91.4%) and An. coluzzii (8.1%) and included one An. coluzzii/An. gambiae hybrid specimen. All mosquitoes screened in Ojoo (n = 26) were An. gambiae. The 1014F kdr mutation was detected at frequencies of 24.5 and 5.8% in Bodija and Ojoo, respectively. No correlation was observed between kdr genotypes and resistance phenotypes. The results indicate that metabolic resistance probably plays an important role in the development of resistance and highlight the need to implement insecticide resistance management strategies.     

Bacteriological and haematological studies of clinical mastitis in goats in Ibadan, OYO State, Nigeria

An investigation was undertaken to identify the bacteria from clinical cases of caprine mastitis in Ibadan and to compare the haematological values of mastitic and non-mastitic does. Bacteriological examination of milk samples from 35 clinically affected udders was performed. A total of 53 bacterial isolates belonging to seven bacteriological genera, were recovered from the milk of the mastitic does examined. The coagulase-negative staphylococci (Staphylococcus epidermidis) were the most common pathogen in this study with an incidence of (50.9%); followed by Escherichia coli with (15.1%) incidence, while Streptococcus species and Bacillus cereus had an incidence of 9.4 and 7.5%, respectively. However, Mannhiemia (P.) haemolytica, Corynebacterium species and Klebsiella pneumoniae showed an incidence of 5.7%, respectively. The profile of bacteria encountered in this investigation are among the pathogen that have been incriminated as sources of contamination of fresh milk meant for human consumption and are therefore of public health importance.

The haematological values of mastitic and non-mastitic does were compared statistically. The erythrocytic values of mastitic does were significantly (P < 0.05) lower than that of the non-mastitic does. However, the total and differential leucocyte counts of the mastitic does were significant (P < 0.05) higher than that of the non-mastitic does. The full haematological counts are true reflection of the health status of an animal. Total and differential leucocyte counts in lactating does are true reflection of mastitis and will even assist the clinicians in predicting the prognosis of mastitic animals.