COMPARATIVE STUDY ON THE LEVEL OF BACTERIOLOGICAL CONTAMINATION OF AUTOMATIC TELLER MACHINES, PUBLIC TOILETS AND PUBLIC TRANSPORT COMMERCIAL MOTORCYCLE CRASH HELMETS IN KIGALI CITY, RWANDA.

BACKGROUND: The environments can be contaminated by infectious agents that constitute a major health hazards as sources of community and hospital-acquired infections due to various activities. OBJECTIVE: A comparative study on the level of bacteriological contamination of automatic teller machines (ATMs), public toilets and commercial motorcycle crash helmets were conducted in Kigali city during the period of January to March, 2013. DESIGN: Samples were collected from selected ATMs, public toilets and commercial motorcycle crash helmets surfaces. Micro-organisms identified from these samples were associated to infecting organisms recovered from unwashed hands surfaces and recorded results in the nearby hospital. SETTING: Samples from each device and subject were transported to the laboratory where they were analysed for the presence of coliforms and other airborne, human skin and intestinal disease causing microorganisms. Microbiological methods including spread plate techniques and some biochemical tests were used to partially identify the microorganisms. SUBJECTS: Subjects involved in this study were consented students from University of Rwanda and Kigali motorcyclists for collections of samples from hands and crash helmets respectively. RESULTS: The following pathogenic bacteria have been found on the devices, Staphylococcus aureus, Staphylococcus epidermis, Streptococcus species, Escherichia coli, Salmonella, Klebsiella, Enterobacter aerogenes, Pseudomonas. The commercial motorcycle crash helmets had the highest level of bacteriological contamination compared to ATMs and public toilets. There was no growth observed on samples collected after treatment from ATMs, public toilets, and commercial motorcycle crash helmets. Attempt to correlate this finding with infecting organisms recovered from unwashed hands surfaces and recorded results in the nearby hospital show that the presences of some of these infectious pathogens. CONCLUSION: This study has revealed the ability of these public devices to serve as vehicle of transmission of microorganisms with serious health implications. To improve and ensure the safety of these public devices the use of disinfectants is of high importance on reducing bacteriological load on those public devices. Proper cleaning regimen to sanitise these facilities regularly and public education on their hygienic usage are recommended to reduce the associated risks.

Serological and molecular epidemiology of measles virus outbreaks reported in Ethiopia during 2000-2004.

Twenty-eight outbreaks in six regions and two major cities in Ethiopia from 2000 to 2004 were investigated, with the collection of 207 venous blood and/or oral fluid samples. Measles diagnosis was confirmed by detection of measles-specific IgM and/or detection of measles virus by polymerase chain reaction (PCR). Of 176 suspected cases tested for specific measles IgM, 142 (81%) were IgM positive. Suspected cases in vaccinated children were much less likely to be laboratory confirmed than in unvaccinated children (42% vs. 83%, P < 0.0001). Of 197 samples analyzed by RT-PCR measles virus genome was detected in 84 (43%). A total of 58 wild-type measles viruses were characterized by nucleic acid sequence analysis of the nucleoprotein (N) and hemagglutinin (H) genes. Two recognized genotypes (D4 and B3) were identified. Each outbreak comprised only a single genotype and outbreaks of each genotype tended to occur in distinct geographical locations. B3 was first observed in 2002, and has now been the cause of three documented outbreaks near to the border of Sudan. D4 genotype was previously observed in an outbreak in 1999 and occurs in more diverse locations throughout the country. These data yield insights into geographical and age-related sources of continued transmission. Refinement of measles control measures might include targeting older age groups (5-14 years) and strengthening routine immunization particularly where importation of cases is a concern.

Evaluation of a commercial rubella IgM assay for use on oral fluid samples for diagnosis and surveillance of congenital rubella syndrome and postnatal rubella.

BACKGROUND: Clinical diagnosis (surveillance) of rubella is unreliable and laboratory confirmation is essential. Detection of virus specific IgM in serum is the most commonly used method. However, the use of serum necessitates the drawing of blood, either through venipuncture or finger/heel prick, which can be difficult in young babies. Oral fluid samples have proved useful as an alternative, less invasive sample for virus specific IgM detection however until recently no commercial rubella IgM tests were available, restricting the usefulness of this approach. OBJECTIVES: To evaluate the performance of the Microimmune Rubella IgM capture EIA using oral fluid samples from outbreaks as well as in cases of suspected congenital rubella syndrome (CRS). STUDY DESIGN: Paired serum and oral fluids were collected from cases during a rubella outbreak in three provinces in Turkey. Matched serum and oral fluid samples were collected from children with suspected CRS in an active surveillance programme at the Aravind Eye Hospital in South India. Serum samples were collected as part of the measles surveillance programme in Ethiopia. RESULTS: On serum samples the sensitivity and specificity of the Microimmune Rubella IgM capture EIA compared to Behring Enzygnost rubella IgM test was 96.9% (62/64; 95% CI 94.2-100%) and 100% (53/53; 95% CI 93.2-100%). On oral fluids compared to matched Behring results on serum the sensitivity was 95.5% (42/44; 95% CI 84.5-99.4%). The sensitivity and specificity of Microimmune Rubella IgM capture EIA on oral fluids from suspected CRS cases compared to serum results using Behring Enzygnost IgM assay was 100% (95% CI 84.5-100%) and 100% (95% CI 95.8-100.0%) respectively. CONCLUSION: Microimmune Rubella IgM capture EIA has adequate performance for diagnosis and surveillance of rubella in outbreak using either serum or oral fluid specimens.

Improving sensitivity of oral fluid testing in IgG prevalence studies: application of mixture models to a rubella antibody survey.

A method for the analysis of age-stratified antibody prevalence surveys is applied to a previously reported survey of antibody to rubella virus using oral fluid samples in which the sensitivity of the assay used was shown to be compromised. The age-specific distribution of the quantitative results of antibody tests using oral fluids is modelled as a mixture of strong positive, weak positive and negative components. This yields maximum likelihood estimates of the prevalence at each age and demonstrates that, when used in conjunction with mixture modelling techniques, the results of antibody prevalence studies using oral fluids accurately reflect those obtained using sera.

Measles virus strains circulating in Ethiopia in 1998-1999: molecular characterisation using oral fluid samples and identification of a new genotype.

A measles outbreak in December 1998 in Bedelle (vaccine coverage <40%) and two sporadic cases in Addis Ababa, Ethiopia, were investigated. Paired serum and oral fluid samples were collected 2-8 days after the onset of symptoms. A total of 53 of 55 outbreak cases and both sporadic cases were positive for serum measles virus-specific IgM. Oral fluid measles-specific IgM was positive in 71% of cases collected up to 5 days after onset and in 90% collected at 6-8 days. By contrast, 100% of oral fluid samples were positive for measles virus RNA by RT-PCR, suggesting that early collection of samples favoured the detection of measles virus RNA by RT-PCR. The measles virus strain in the outbreak was identified as genotype D4. One strain from a sporadic case was also genotype D4; the strain from the other sporadic case was assigned to clade D but was distinct. The degree of divergence from recognised clade D strains suggested that, together with three strains from the United Kingdom, it represents an additional genotype of clade D (GenBank accession numbers AF280800-280807).

Has oral fluid the potential to replace serum for the evaluation of population immunity levels? A study of measles, rubella and hepatitis B in rural Ethiopia.

OBJECTIVE: To assess the suitability of using oral-fluid samples for determining the prevalence of immunity to vaccine-preventable infections. METHODS: Paired blood and oral-fluid samples were obtained from 853 individuals of all ages from a rural Ethiopian community. Oral fluid around the gums was screened for measles- and rubella-specific antibodies using enhanced IgG antibody capture (GAC) enzyme-linked immunosorbent assays (ELISAs), and for anti-HBc antibodies using a prototype GACELISA. IgG antibodies in serum to measles, rubella and HBc were determined using commercial ELISAs. FINDINGS: Relative to serum, oral fluid assay sensitivity and specificity were as follows: 98% and 87% for measles, 79% and 90% for rubella, and 43% and 87% for anti-HBc. These assay characteristics yielded population prevalence estimates from oral fluid with a precision equal to that of serum for measles (all ages) and rubella (ages < 20 years). CONCLUSION: Our results suggest that oral fluid could have the potential to replace serum in IgG antibody prevalence surveys. Further progress requires assessment of variation in assay performance between populations as well as the availability of standardized, easy to use assays.

Maternal rubella-specific antibody prevalence in Ethiopian infants.

In countries with a high transmission rate of rubella the optimal age for universal rubella vaccination of infants is critically dependent upon the rate of loss of maternal antibodies. Few studies have investigated the decay characteristics of such antibodies. Mother:infant pairs were recruited at the Ethio-Swedish Children's Hospital, Addis Ababa, in 1994/95. Rubella antibody levels, determined by radial haemolysis, were available for analysis from 1542 infants aged 0-12 months, with 942 repeat measures, and from 846 mothers. Decay in seropositivity was well described by a delayed exponential function. The proportion seropositive at age 6, 9, or 12 months was 6-13%, 1-4%, or 0-1%, respectively, dependent upon assay cutoff level. Only infant age and mother's antibody level were important predictors of seropositivity. Results suggest that the success of vaccination at age 9 months or above would be little affected by residual maternal antibodies.

Sero-epidemiology of rubella in the urban population of Addis Ababa, Ethiopia.

We conducted a community-based cluster sample survey of rubella sero-epidemiology in Addis Ababa, Ethiopia in 1994. Among 4666 individuals for whom complete data were available, rubella antibody prevalence was 91% (95% confidence interval: 90, 92). On multivariable analysis, seroprevalence was lower among individuals who were resident in Addis Ababa for 1 year or less. Approx. 50% seroprevalence was attained by age 4 years, and the estimated average age at infection was 5.2 years. The highest age-specific force of infection was estimated to occur in 5- to 9-year-olds. The early age at infection corresponded with a low estimated incidence of congenital rubella syndrome (CRS) of 0.3 per 1000 live births, equivalent to nine cases of CRS in 1994. The predicted critical level of immunity for elimination of rubella via vaccination was 85-91%, requiring 89-96% coverage with a vaccine of 95% effectiveness. Unless very high coverage of rubella vaccine could be guaranteed, the introduction of childhood vaccination could increase the incidence of CRS in Addis Ababa.

Detection of measles specific IgG in oral fluid using an FITC/anti-FITC IgG capture enzyme linked immunosorbent assay (GACELISA).

An IgG antibody capture enzyme linked immunosorbent assay (GACELISA) for the detection of measles specific IgG in oral fluid was developed using an FITC/anti-FITC amplification system. The GACELISA was evaluated by testing paired oral fluid and serum samples from 787 subjects in an epidemiological study of measles in rural Ethiopia. Oral fluids were tested by GACELISA and corresponding serum samples by a sensitive indirect ELISA for measles IgG (Behring Enzygnost). By comparison with the serum measles IgG assay, the oral fluid GACELISA had a sensitivity of 97.4% (95% confidence intervals: 95.9, 98.2) and a specificity of 90.0% (81.9, 94.3), with no significant differences observed by age group. Total IgG concentrations were measured on a subset of 160 oral fluids by an in-house ELISA. This showed that false negative GACELISA results tended to occur in samples with low concentrations of total IgG, although the trend was not statistically significant. It is concluded that the overall performance of the GACELISA was satisfactory, showing close agreement to the serum ELISA, and has potential to serve as an easily transferable tool for large scale epidemiological studies as required for the World Health Organisation's programme for the global control of measles.

A comparison of oral fluid and serum for the detection of rubella-specific antibodies in a community study in Addis Ababa, Ethiopia.

OBJECTIVE: To assess the utility of oral fluid compared with serum for the determination of age-prevalence of rubella-specific antibodies in an urban African community setting. METHOD: Paired serum and oral fluid samples were collected from 439 individuals aged 0-49 years in Addis Ababa, Ethiopia, as part of a larger seroepidemiological survey in 1994. Oral fluid was sampled using a simple sponge device that was well accepted by subjects of all ages; venous blood was collected by Vacutainer system. We measured rubella-specific antibodies in serum by the Radial Haemolysis (RH) test, supported by two confirmatory assays, and in oral fluid by IgG antibody-capture radioimmunoassay (GACRIA). RESULTS: Sensitivity and specificity of oral fluid results compared to serum were 89% and 76%, respectively. Sensitivity declined from 96% in age group 0-19 years to 90% in age group 20-29 and 78% in age group 30-49. Specificity was 86% in 0-9 year olds contrasting with 61% in older groups (10-49 years). The positive predictive value of an oral fluid sample was high in all age groups (range 92-100%), while the negative predictive value declined from > or =80% in those aged <10 years to <10% in those aged > or =30 years. Serum confirmatory tests suggested a proportion of false serum RH negatives, increasing with age, indicating a need to standardize serum as well as oral fluid tests. CONCLUSION: In the community setting of a developing country, oral fluid surveys could be useful to estimate age-prevalence of rubella immunity and identify rubella-susceptible children for follow-up. Further work is required to simplify assays and sample processing, improve assay sensitivity and estimate assay specificity more precisely, and compare and standardise collection methods suitable for surveillance of a variety of childhood viral infections.

An evaluation of oral-fluid collection devices for the determination of rubella antibody status in a rural Ethiopian community.

We compared 3 different oral-fluid collection devices to assess their suitability for use in community studies of rubella antibody. Of 58 individuals enrolled from 13 households from a southern Ethiopian village, 38 provided a blood sample and oral fluids by the 3 devices: 2 proprietary, Omni-SAL and OraSure, and a third a polystyrene sponge swab (Sponge). The Sponge swab, used like a toothbrush, was most acceptable to survey staff and to participants of all ages, although it proved ill-adapted for fluid extraction. The other devices more often caused participant discomfort or anxiety, particularly in the young. Statistical comparison of rubella-specific immunoglobulin (Ig) G in oral fluid, measured by antibody-capture radioimmunoassay, and in serum, by indirect enzyme-linked immunosorbent assay, showed no clear differences between the devices in oral-fluid performance. Specificity range was 75-100% and sensitivity 73-85%, relative to serum. Specific-antibody levels declined with increasing age, with concomitant decreases in sensitivity, as previously documented. The relationship between specific IgG and total IgG in oral fluid differed by device. Specific IgG levels were highly correlated between paired samples using the Sponge device. We consider the Sponge device to be the most suitable for community survey work, although the extraction method requires improvement. Further work is needed to improve the sensitivity of antibody status determination in adults.

Test for association of DDT resistance with inversion polymorphism in Anopheles arabiensis from Ethiopia.

Association of DDT resistance levels with chromosome inversion polymorphism was investigated in Anopheles arabiensis samples collected from southwestern Ethiopia. The frequencies of the 2Ra, 2Rd, and 3Ra inversions in 1988 and 1990 between the DDT survivors pooled from the 3 times of exposure and unexposed controls did not differ significantly. However, for 2Rb a significant association was observed (Mantel-Haenszel chi 2, stratified for year of collection = 10.4, P < 0.001). The inversion frequency was 56% among unexposed individuals, but it was 64-92% among those surviving exposure.

Some aspects of malaria prevalence; vector infectivity and DDT resistance studies in Gambella region; South Western Ethiopia

Prevalence of plasmodium falciparum and plasmodium vivax in the human population; infectivity and DDT resistance of Anopheles mosquitoes were studied on samples collected during the peak malaria season of 1990 from Gambella; South West Ethiopia. Mosquito vectors collected were assorted into species and their infectivity with malaria parasites was determined by the enzyme-linked immunosorbent assay (ELISA). In the human population out of a total of 821 individuals examined from nine villages; 4.1 percent (34) were found to be positive for malaria parasites. Of the 34 positive individuals 5.9 percent (2) were positive for plasmodium vivax and 94.1 percent (32) for plasmodium falciparum. Although relatively high positivity rates for malaria were observed in 1-4 and 5-14 age groups; the difference in rates of positivity was not statistically significant for the whole population (p=0.5077). However; a significant difference in parasite prevalence was detected between the nine localities. Compared to that of 1989; the overall malaria prevalence rate in the human population significantly decreased in 1990. Insecticide susceptibilty studies revealed the presence of DDT resistant Anopheles gambiae s.l. mosquito in Itang. Furthermore; a strong evidence would suspect the vectorial status of A. pharoensis was obtained by detecting salivary gland sporozoite antigens of P. vivax in the head region of two mosquitos. Sporozoite rate of 0.76 percent (P. falciparum) for A. gambiae s.l. and 0.47 percent (P. vivax) for A. pharoensis were determined

Plasmodium vivax and P. falciparum epidemiology in Gambella, south-west Ethiopia.

Plasmodium vivax and P. falciparum epidemiology were studied for parasitological and entomological samples collected during the period 1989 and 1990, respectively, from Gambella, South West Ethiopia. Of the total population examined (n = 1091), 147 (13.5%) were found to be positive for malaria parasites. Prevalence rates among males and females were 13.8% and 13.1%, respectively. Differences in the prevalence rates of malaria in the eleven villages were observed, the highest (33.3%) being in Ukuna 2 and the lowest (3.9%) in Ukuna 22. The dominant species of malaria found were both P. falciparum and P. vivax. 88.9% and 11.1% of the malaria cases of the general population were due to these parasites, respectively. It was also recognized that P. falciparum and P. vivax were prevalent in 81.6% and 18.4% of the Anuak population, respectively. The mosquito species responsible for malaria transmission were the indoor-resting A. gambiae s. l. and A. pharoensis. The parasite infection rates of these species were 0.76% and 0.46% and they were found to be the exclusive vectors of P. falciparum and P. vivax, respectively. The present findings are not in accord with the study results previously reported twenty years ago by Armstrong (1972) and Krafsur (1971). The most probable contributing factors for such switch of malaria transmission patterns were, the rehabilitation and resettlement programmes and agricultural activities undertaken in Gambella for the past 10 years that may have brought changes of the socio-economic situation and environmental factors.