- A-Z Publications
- Southern African Journal of Epidemiology and Infection
- Previous Issues
- Volume 27, Issue 4, 2012
Southern African Journal of Epidemiology and Infection - Volume 27, Issue 4, 2012
Volume 27, Issue 4, 2012
Author Charles FeldmanSource: Southern African Journal of Epidemiology and Infection 27 (2012)More Less
We live in a rapidly changing world, and many of the changes that occur impact directly on various aspects of our lives, and possibly even on the journals we read. The Southern African Journal of Epidemiology and Infection (SAJEI) has been through many changes over the years. Recently, very positive changes have occurred. The journal has changed its outward appearance to take on a more modern, fresh look.
Source: Southern African Journal of Epidemiology and Infection 27, pp 141 –148 (2012)More Less
It is estimated that up to 40% of acute gastroenteritis cases are undiagnosed. Rotavirus is a primary aetiological agent, so the introduction of vaccines into the national immunisation programmes of many countries, including South Africa, has shown promise in reducing the burden of disease and decreasing hospital admissions. Recently, several novel viruses have been isolated in association with gastroenteritis, although their epidemiology and clinical significance are poorly understood. This article highlights the importance of rotavirus in diarrhoeal disease. A review is provided of the molecular biology of emerging pathogens in the Picornavirus family.
Detection and management of acute HIV infections in patients with sexually transmitted infections : a window of opportunity for HIV prevention within South Africa? : reviewSource: Southern African Journal of Epidemiology and Infection 27, pp 149 –155 (2012)More Less
Patients with acute human immunodeficiency virus (HIV) infection are highly infectious to their uninfected sexual partners. The level of this infectiousness is thought to be as much as 26 times greater than that observed during chronic HIV infection, and may be further elevated in patients with coexisting sexually transmitted infections (STI). The sexual partners of acute HIV infection patients with STIs may be more vulnerable to HIV acquisition, because of genital tract inflammation and ulcerations. Data from international and South African studies demonstrate that STI patients are a high-risk population for acute HIV infection. However, most acute HIV infection cases remain clinically undiagnosed, and scoring algorithms offer little assistance to physicians and nurses in terms of improving their diagnostic ability. Laboratory testing of blood specimens remains the only effective means of diagnosis. Laboratory costs have been reduced through the use of pooling strategies for HIV nucleic acid detection, and algorithms that incorporate dual HIV rapid tests and ultrasensitive p24 antigen assays. The availability of these diagnostic tools and antiretroviral drugs means that there is a window of opportunity to enhance HIV prevention activities in South Africa. This can be achieved by screening STI patients for acute HIV infection, in order to initiate appropriate medical management, risk reduction counselling and partner notification.
Author A. RevelasSource: Southern African Journal of Epidemiology and Infection 27, pp 156 –162 (2012)More Less
Acute gastroenteritis represents a major cause of morbidity and mortality worldwide. Young children are affected most frequently, with three to 10 episodes of diarrhoea per subject per year, a rate that decreases to less than one episode annually for children over five years of age and adults. Usually, deaths are a result of dehydration, but malnutrition also plays an important role. Furthermore, malnutrition increases the incidence and severity of diarrhoea, as well as of other infections. The clinician encounters acute gastroenteritis in three settings. The first is sporadic gastroenteritis in infants, which is often caused by rotavirus. The second is epidemic gastroenteritis, which occurs either in semi-closed communities (e.g. families, institutions, on ships, at vacation spots) or as a result of classic food-borne or water borne pathogens. Most of these infections are caused by caliciviruses. The third is sporadic acute gastroenteritis of adults, which is most likely to be caused by caliciviruses, rotaviruses, astroviruses or adenoviruses.
Source: Southern African Journal of Epidemiology and Infection 27, pp 164 –168 (2012)More Less
The hypervirulent polymerase chain reaction (PCR) ribotype 027 strain of Clostridium difficile produces toxins A, B and a binary toxin. Toxin detection kits are commonly used in diagnostic laboratories, but have been unsuccessful in detecting all of the relevant C. difficile strains, and the toxins produced. In this study, conventional PCR was used to detect the presence of the genes of toxin A, toxin B and the binary toxin of C. difficile. Eighty-four frozen (collected between 2006-2007) and 13 fresh (collected in 2010) stool specimens, obtained in Pretoria, were analysed. The genes for toxin A, toxin B and the binary toxin were detected in one of the fresh stool specimens. This may have implications for healthcare facilities, and suggests the possible emergence of the highly virulent PCR ribotype 027 strain of C. difficile in Pretoria. This emphasises the importance of continuous surveillance and monitoring of C. difficile outbreaks.
Source: Southern African Journal of Epidemiology and Infection 27, pp 169 –182 (2012)More Less
There has been a substantial amount of recent modelling work in multivariate disease-mapping models in epidemiology. These models provide information on similarities, as well as differences, on the effect of risk factors among diseases. Additionally, they can be used to identify disease-specific risk factors, which would otherwise have been masked by established factors. The purpose of this article is to provide a review of the biostatistics literature, by comparing four joint disease-mapping models. In particular, multivariate intrinsic conditional autoregressive (ICAR) and multivariate multiple membership multiple classification (MMMC) models, as well as, shared-component and proportional mortality models are compared, with regard to similarities and differences between the assumptions and inferences. As an illustration, the four different models are fitted to population-based oesophagus and stomach cancer data. These two cancers share common risk factors associated with smoking, and diet or alcohol consumption. The four methods produce similar substantive findings. However, the shared component model adds more versatility in answering more substantive epidemiological questions, than the other three models. The review article provides a useful reference for epidemiologists, and public health researchers and planners, who are interested in disease mapping. In order to promote the uptake of these models, and aid their implementation by non-experts, WinBUGS® codes used to fit the models are provided as supplementary material.
GSTM1, GSTP1 and NQO1 polymorphisms and susceptibility to asthma among South African children : original researchSource: Southern African Journal of Epidemiology and Infection 27, pp 184 –188 (2012)More Less
Gluthathione-S-transferase (GSTM1 and GSTP1) and nicotinamide quinone oxidoreductase (NQO1) genes play an important role in cellular protection against oxidative stress, which has been linked to asthma pathogenesis. We investigated whether common, functional polymorphisms in GSTM1, GSTP1, and NQO1 influence susceptibility to asthma among schoolchildren in South Africa. Genomic deoxyribonucleic acid (DNA) was extracted from 317 primary schoolchildren, aged 9-11 years, from the urban, underprivileged socio-economic communities of Durban. GSTM1 (null vs. present genotype), GSTP1 (Ile105Val; AA →AG+GG) and the NQO1 (Pro/Ser; CC →CT/TT) genotypes were determined using polymerase chain reaction. Among the children, 30% were GSTM1 null, 65% carried the G allele for GSTP1, and 36% carried the C allele for NQO1. There was a high prevalence of asthma of any severity (46.1%), with 20.4% reporting persistent asthma. The GSTP1 AG+GG polymorphic genotype was significantly associated with persistent asthma (adjusted OR = 3.98; CI = 1.39, 11.36, p-value = 0.01). Neither the GSTM1, nor the NQO1, genotype was a significant predictor of persistent asthma. Therefore, the GSTP1 A/G variant may modulate the risk of persistent asthma among our sample.
Comparison of empyema thoracis in HIV-infected and non-infected patients with regard to aetiology and outcome : original researchSource: Southern African Journal of Epidemiology and Infection 27, pp 189 –194 (2012)More Less
Empyema thoracis remains a problem in developing countries. Human immunodeficiency virus (HIV) is a risk factor for the development of empyema. There is a clinical impression that HIV-infected patients with empyema have worse outcomes. This study was conducted to assess whether HIV infection affected aetiology or outcomes of patients with empyema. A retrospective review was conducted of 172 patients, meeting established criteria for the diagnosis of empyema, who were admitted to Chris Hani Baragwanath Hospital between January 2006 and December 2009. HIV-infected and non-infected patients were evaluated for differences in aetiology and outcomes, including length of stay, surgical intervention and local complications of closed-tube thoracostomy. A sub-analysis of HIV-infected patients stratified according to CD4 cell count and use of antiretrovirals (ARVs) was also performed. Of the 172 patients, 125 (73%) were HIV infected, and 47 (27%) were non-infected. HIV-infected patients with lower CD4 cell counts were more likely to be diagnosed with clinical tuberculosis. More commonly, the aetiology of empyema was not determined in HIV-non-infected patients. HIV-infected patients on ARVs were more likely to have thoracic surgery and had shorter hospital stays than those not on ARVs. This study failed to demonstrate any significant differences in aetiology among HIV-infected vs. non-infected patients with empyema. There was a trend towards more Gram-negative infections in the HIV-infected group. ARV use was associated with improved outcomes with regard to cardiothoracic intervention and length of hospital stay.
Health-seeking behaviour of people with sexually transmitted infections in the community of Nkomazi East, Mpumalanga : original researchSource: Southern African Journal of Epidemiology and Infection 27, pp 195 –198 (2012)More Less
The control of sexually transmitted infections (STIs) is a priority for the World Health Organization. It is estimated that there are 11 million cases of STIs per year in South Africa. Health-seeking and sexual behaviours are important in the management of STIs. The aim was to assess the health-seeking behaviour of people who had STIs in the community of Nkomazi East, Mpumalanga. The study design was a descriptive cross-sectional survey. Participants included patients who presented with confirmed signs or symptoms of an STI, were 16 years or older, voluntarily agreed to participate in the study and were residents of the community. A total of 332 questionnaires were collected. The majority of the participants were single, literate, unemployed black patients aged from 16-23 years (43.7%). Participants were very knowledgeable about STIs. Urethral discharge, painful micturition, vaginal discharge and lower abdominal pain were the most commonly recognised STI symptoms. All the participants (100%) sought help when they thought that they had an STI. Their preferred source of help was the public healthcare sector. Traditional healers were also consulted frequently. While compliance to treatment was satisfactory, ongoing unsafe sexual practices were common among participants who had active STIs. The respondents had a good knowledge of STI symptoms and signs and sought help early, usually from public healthcare facilities. STI health-seeking behaviour was influenced by multiple factors. This study suggests that STI control programmes should be designed around public healthcare facilities. However, adequate knowledge of STIs did not deter many respondents from engaging in unprotected sexual activity, sometimes with multiple partners.
Source: Southern African Journal of Epidemiology and Infection 27, pp 199 –200 (2012)More Less
Two cefpodoxime-resistant Neisseria gonorrhoeae isolates were identified with high minimum inhibitory concentrations (MIC) for oral cephalosporins. The ceftriaxone MICs for both isolates were still in the susceptible range, although raised at 0.064 mg/l. Both isolates were cultured from urethral specimens that were collected from male patients who had presented to their general practitioners with urethral discharge. Patient 1 was treated empirically with azithromycin. Patient 2, who reported having had sex with other men, was given intravenous ceftriaxone as he had recently failed two courses of oral cefixime. Both isolates were also highly resistant to ciprofloxacin, resistant to penicillin (β-lactamase negative) and resistant to tetracycline (and thus doxycycline), and exhibited decreased susceptibility to both azithromycin and gentamicin. On molecular testing, both isolates were found to have mosaic penA genes, which encode for penicillin-binding protein 2. Mosaic penA gene formation is the most common genetic mechanism that is associated with decreased susceptibility to oral cephalosporins. The isolates were typed using the highly discriminatory N. gonorrhoeae multiantigen sequence typing scheme and were found to have identical sequence types. This indicates that it is likely that there has been transmission of a single strain within Gauteng. It is probable that the two cases may be part of the same sexual network.
Source: Southern African Journal of Epidemiology and Infection 27, pp 201 –204 (2012)More Less
On 19 August 2011, 11 suspected cholera cases were reported by three private hospitals to the Disease Surveillance Unit of Ede District in Osun State, Nigeria. Diagnoses were confirmed using the cholera rapid diagnostic test kit. A field investigation to provide descriptive epidemiology of the outbreak was conducted. There were 148 cases and eight deaths, giving a case fatality rate of 5%. Twelve of the 30 districts in the state were affected. Female cases constituted more than half (51%, n = 76). The distribution of cases by age category showed a higher incidence in the age group ≥ 15 years (61%, n = 90). The need to monitor the occurrence of cases closely and to provide continuous public enlightenment on household hygienic practices was emphasised.
Source: Southern African Journal of Epidemiology and Infection 27, pp 205 –209 (2012)More Less
Infections in travellers returning to their home country often represent a diagnostic challenge. In addition, there is always the potential for these diseases to be transmissible. We describe a case of a young woman who returned from Sri Lanka with features of a haemorrhagic illness, subsequently identified as dengue fever. Whereas dengue is not endemic to South Africa, it is probable that we will see more cases as the "footprint" of this disease expands. Johannesburg, as the gateway to Africa, is frequently on the itinerary of travellers into Africa, and of those returning home. In addition, the whole country has a large Indian diaspora who frequently return home with illnesses that are not endemic to this country. Constant vigilance is required to both treat these illnesses, and to ensure that nosocomial transmission does not occur.