Viral etiologies of lower respiratory tract infections in children < 5 years of age in Addis Ababa, Ethiopia: a prospective case-control study.

BACKGROUND: Lower respiratory tract infections (LRTIs) are a major cause of morbidity and mortality in children worldwide and disproportionally affect Sub-Saharan Africa. Despite the heaviest burden of LRIs in Ethiopia, to date, no published studies have reported a comprehensive viral etiology of LRTIs among children in Ethiopia. The objective of this study was to determine and estimate the etiological contribution of respiratory viruses to LRTIs in < 5 years children in Ethiopia. METHODS: A prospective case-control study was conducted from September 2019 to May 2022 in two major governmental hospitals, St. Paul Hospital Millennium Medical College and ALERT Hospital in Addis Ababa, Ethiopia. Nasopharyngeal/oropharyngeal samples and socio-demographic and clinical information were collected from children under 5 years. A one-step Multiplex real-time PCR (Allplex™ Respiratory Panel Assays 1-3) was done to detect respiratory viruses. STATA software version 17 was used for the data analysis. We computed the odds ratio (OR), the attributable fraction among exposed (AFE) and the population attributable fraction (PAF) to measure the association of the detected viruses with LRTIs. RESULTS: Overall, 210 LRTIs cases and 210 non-LRTI controls were included in the study. The likelihood of detecting one or more viruses from NP/OP was higher among cases than controls (83.8% vs. 50.3%, p = 0.004). The multivariate logistic regression showed a significantly higher detection rate for RSV A (OR: 14.6, 95% CI 4.1-52.3), RSV B (OR: 8.1, 95% CI 2.3-29.1), influenza A virus (OR: 5.8, 95% CI 1.5-22.9), and PIV 1 (OR: 4.3, 95% CI 1.1-16.4), among cases when compared with controls. The overall AFE and PAF for RSV A were (93.2% and 17.3%), RSV B (87.7% and 10.4%) and Influenza A virus (82.8% and 6.3%), respectively. The mean CT values were significantly lower for only RSV B detected in the case groups as compared with the mean CT values of RSV B detected in the control group (p = 0.01). CONCLUSIONS: RSV, Influenza A and PIV 1 viruses were significantly associated with LRTIs in < 5 years children in Addis Ababa, Ethiopia. Therefore, we underscore the importance of developing prevention strategies for these viruses in Ethiopia and support the importance of developing and introducing an effective vaccine against these viruses.

Characterization of potential probiotic starter cultures of lactic acid bacteria isolated from Ethiopian fermented cereal beverages, Naaqe, and Cheka.

AIMS: To test the in vitro probiotic potential and starter culture capacity of lactic acid bacteria (LAB) isolated from Naaqe and Cheka, cereal-based Ethiopian traditional fermented beverages. METHODS AND RESULTS: A total of 44 strains were isolated from spontaneously fermented Ethiopian cereal-based beverages, Naaqe and Cheka with 24 putatively identified as LAB and 14 identified up to the species level. The species Limosilactobacillus fermentum (6/12; 50%) and Weissella confusa (5/12, 41.67%) were the predominant species identified from Naaqe, while the two Cheka isolates were L. fermentum and Pediococcus pentosaceus. Six LAB strains inhibited eight of the nine gastrointestinal indicator key pathogens in Ethiopia, including Escherichia coli, Salmonella enterica subsp. enterica var. Typhimurium, Staphylococcus aureus, Shigella flexneri, and Listeria monocytogenes. Three of the LAB isolates exhibited strain-specific immunostimulation in human monocytes. Based on these probiotic properties and growth, six strains were selected for in situ evaluation in a mock fermentation of Naaqe and Cheka. During primary fermentations, L. fermentum 73B, P. pentosaceus 74D, L. fermentum 44B, W. confusa 44D, L. fermentum 82C, and Weissella cibaria 83E and their combinations demonstrated higher pH-lowering properties and colony-forming unit counts compared to the control spontaneous fermentation. The same pattern was also observed in the secondary mock fermentation by the Naaqe LAB isolates. CONCLUSIONS: In this study, we selected six LAB strains with antipathogenic, immunostimulatory, and starter culture potentials that can be used as autochthonous probiotic starters for Naaqe and Cheka fermentations once their health benefit is ascertained in a clinical trial as a next step.

Molecular Characterization of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae Isolates Collected from Inanimate Hospital Environments in Addis Ababa, Ethiopia.

INTRODUCTION: The hospital environment contributes to the spread of Extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE), which are contributing to increased morbidity and mortality rates. The present study was carried out to detect environmental contamination, antimicrobial susceptibility testing of ESBL-PE, and to explore molecular characterization of ESBL encoding genes. METHODS: A cross-sectional study was conducted within the intensive care units (ICUs) of Tikur Anbessa Specialized Hospital from June to July 2018. A total of 97 swabs were taken from high-contact inanimate surfaces near immediate patient environments. All isolates were cultured by using ESBL ChromoSelect Agar and identified with conventional bacteriological methods. Antimicrobial susceptibility testing was performed as recommended by Clinical and Laboratory Standards Institute. Combination disk test was used to confirm ESBL production, while molecular characterizations of ESBL genes were performed by polymerase chain reaction. RESULTS: Out of 97 swabbed sample, 24 (24.7%) were confirmed as ESBL-PE. The most predominant ESBL-PE was from E. coli (41.7%) and K. pneumoniae (25%). The Pediatrics and Neonatal ICU (29.2%, 7/24) exhibited highest ESBL-PE. The most contaminated materials were bed linens (33.3%). Most of ESBL-PE isolates were resistant to ampicillin (100%) and ceftriaxone (91.7%). A low resistance level was recorded for amikacin (25%). Among ESBL-producing genes, blaCTX-M (35.7%) was the most prevalent, followed by blaTEM and blaSHV gene 32.1% for each. CONCLUSIONS: Appearance of ESBL-PE in ICUs environment is posing a serious threat to control healthcare associated infections. The high level of resistance shows the need of policies for devising infection control procedures and detection of ESBL-PE.

Surveillance of Bacterial Meningitis, Ethiopia, 2012-2013.

Among 139 patients with suspected bacterial meningitis in Ethiopia, 2012-2013, meningococci (19.4%) and pneumococci (12.9%) were the major disease-causing organisms. Meningococcal serogroups detected were A (n = 11), W (n = 7), C (n = 1), and X (n = 1). Affordable, multivalent meningitis vaccines for the African meningitis belt are urgently needed.

Chronic meningitis in immunocompromised adult Ethiopians visiting Tikur Anbessa Teaching Hospital and Ye'huleshet Clinic from 2003-2004.

BACKGROUND: Chronic meningitis is inflammation of the meninges where signs and symptoms develop and last for at least four weeks without alleviation. Little is known about the current etiology and incidence of the disease in adults living in developing countries. OBJECTIVE: The objective of this study was to elucidate the most common etiologies of chronic meningitis in adult Ethiopian patients and give an aid in the empiric therapy. METHODOLOGY: A total of 53 adult patients (median age 32 years) having chronic meningitis and who were admitted at Tikur Anbessa Teaching Hospital and Ye'huleshet Clinic, Addis Ababa, Ethiopia were recruited between 2003 and 2004. Of the 53 patients, bacteriological, molecular and immunological investigations were done for 52 of the study participants to detect Cryptococcus neoformans, Mycobacterium tuberculosis, Toxoplasma gondii, Brucella and Neisseria meningitides infections. RESULTS: Forty eight of the participants were HIV positive and 15% (8/52) of the CSF were positive with Cryptococcal latex antigen detection test; in addition, M. tuberculosis DNA was detected using PCR from CSF ofpatients infew of the patients. Multiple infections were observed in studyparticipants with < 0.1 to 1 CD4 to CD8 ratio. CONCLUSION: Chronic meningitis mostly occurred in HIV infected patients, where most of the infections were attributed to Cryptococcus neoformans whereas M. tuberculosis appeared secondary.

A pilot study on detection and genotyping of humanpapilloma virus isolated from clinically diagnosed Ethiopian women having cervical intraepithelial neoplasia.

BACKGROUND: Human Papilloma virus associated cervical cancers are more prevalent in developing countries compared to developed countries. Cervical cancer is reported as the most frequent malignancy among women visiting hospitals in Ethiopia. This study is a pilot study designed to examine the prevalence and genotypes of HPV in twenty Ethiopian women, clinically diagnosed to have cervical neoplasia, while visiting gynecology unit of a tertiary level referral hospital in Addis Ababa. The objective of this study was to detect the presence of HPV L1 gene and respective genotypes among women clinically diagnosed with different grades of cervical neoplasia. METHODOLOGY: A total of 20 fresh biopsy samples were collected from clinically diagnosed cases, DNA extracted and further amplified using PCR for HPV L1 and beta globin genes. The PCR amplicons were denatured and allowed for hybridization onto a nitrocellulose strip containing the type-specific probes for 27 HPV genotypes representing both high and low risk groups as well as beta globin genes. Socio-demographic characteristics and clinical findings of the participants were recorded on structured questionnaires. RESULTS: Amplification of HPV L1 gene by PCR detected 17 cases out of 20. Based on reverse line blot hybridization assay, the most frequent genotype identified was HPV16 (13/20). Mixed infection of HPV 16 with HPV 33, HPV 35, HPV 45 and HPV 58 was detected from other four study participants. CONCLUSION: Human papilloma virus type 16 was the most prevalent genotype identified from the subjects screened. Further investigation with statistically sound sample size would help to clearly visualize the existing trend in Ethiopia regarding factors for high risk HPV positivity and multiple gravidity, young age at first coitus and cervical neoplasia.

Pneumococcal colonization and coinfecting respiratory viruses in children under 5 years in Addis Ababa, Ethiopia: a prospective case-control study.

A comprehensive understanding of the dynamics of Streptococcus pneumoniae colonization in conjunction with respiratory virus infections is essential for enhancing our knowledge of the pathogenesis and advancing the development of effective preventive strategies. Therefore, a case-control study was carried out in Addis Ababa, Ethiopia to investigate the colonization rate of S. pneumoniae and its coinfection dynamics with respiratory viruses among children under the age of 5 years. Samples from the nasopharyngeal and/or oropharyngeal, along with socio-demographic and clinical information, were collected from 420 children under 5 years old (210 cases with lower respiratory tract infections and 210 controls with conditions other than respiratory infections.). A one-step Multiplex real-time PCR using the Allplex Respiratory Panel Assays 1-4 was performed to identify respiratory viruses and bacteria. Data analysis was conducted using STATA software version 17. The overall colonization rate of S. pneumoniae in children aged less than 5 years was 51.2% (215/420). The colonization rates in cases and controls were 54.8% (115/210) and 47.6% (100/210), respectively (p = 0.14). Colonization rates were observed to commence at an early age in children, with a colonization rate of 48.9% and 52.7% among infants younger than 6 months controls and cases, respectively. The prevalence of AdV (OR, 3.11; 95% CI [1.31-8.19]), RSV B (OR, 2.53; 95% CI [1.01-6.78]) and HRV (OR, 1.7; 95% CI [1.04-2.78]) tends to be higher in children who tested positive for S. pneumoniae compared to those who tested negative for S. pneumoniae. Further longitudinal research is needed to understand and determine interaction mechanisms between pneumococci and viral pathogens and the clinical implications of this coinfection dynamics.

Genotyping of human papillomavirus in paraffin embedded cervical tissue samples from women in Ethiopia and the Sudan.

Cervical cancer is the most frequent female malignancy in most developing countries. Previous studies have demonstrated a strong association of human papillomavirus (HPV) infection with dysplasia and carcinoma of the uterine cervix. The objective of this study was to identify the prevailing HPV genotypes responsible for the development of cervical cancer among women in Ethiopia and the Sudan. A molecular characterization of HPV was done on 245 paraffin embedded cervical biopsy samples collected from the two countries. Amplification of HPV and subsequent genotyping was done using SPF10 primers and Line probe assay. Of samples collected from Ethiopian patients, 93% (149/160) and 13% (21/160) had high risk and low risk HPV genotypes, respectively. Among samples collected from the Sudan, 94% (80/85) harbored high risk and 11.7% (10/85) low risk HPV genotypes. Human papillomavirus 16 was the most frequent genotype identified in samples from Ethiopia (91%, 136/149) and the Sudan (82.5%, 66/80). HPV 52, 58, and 18 were the second, third and fourth common genotypes identified in Ethiopia, whereas HPV 18, 45, and 52 were the second, third, and fourth genotypes identified in samples collected from the Sudan. Thus, individuals living in different geographical localities should receive vaccines based on the specific genotypes circulating in the area and a vaccine targeting HPV 16, 18, 45, 52, and 58 may be optimal for the control of cervical cancer in the two countries.

Serum antibodies to Toxoplasma gondii and Herpesvidae family viruses in individuals with schizophrenia and bipolar disorder: a case-control study.

BACKGROUND: Recent etiological studies for schizophrenia and bipolar disorder have focused on the protozoan Toxoplasma gondii and Herpesvirdae family viruses. OBJECTIVE: To determine the magnitude of T. gondii, cytomegalovirus (CMV), herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) infection in individuals with schizophrenia, bipolar disorder and healthy controls by using serologic diagnostic methods. MATERIAL AND METHODS: Serologic diagnostic method was used to determine the prevalence and level of antibodies to T gondii, CMV HSV-1 and HSV-2 in individuals with schizophrenia, bipolar disorder, and unaffected controls recruited from Butajira, Ethiopia. The study was conducted from March to May 2009. A total of 495 serum samples were analysed for the presence and level of immunoglobulin G (IgG) to T. gondii, CMV HSV-1, and HSV-2. RESULTS: The seroprevalence of T gondii infection was higher in individuals with schizophrenia [adjusted odds ratio = 4.7; 95% CI (1.5, 15.1)] and bipolar disorder [adjusted odds ratio = 3.0; 95% CI (1.1, 8.6)] than in unaffected controls. The level of IgG to CMV was also significantly higher in individuals with schizophrenia and bipoar disorder than in unaffected controls. Younger individuals with schizophrenia (< 25 years old) also had a significantly higher level of IgG to CMV than matched unaffected controls. CONCLUSION: This study provides additional evidence that infection with 7T gondii and CMV may be associated with some cases of schizophrenia and bipolar disorder. Additional studies should focus on antibodies to these agents in the sera and CSF of individuals with recent-onset psychosis.

Viral Etiologies of Meningitis in Patients with Presumed Pyogenic Meningitis at University Hospitals in Ethiopia.

INTRODUCTION: Viral meningitis is common in most resource-limited settings, posing a challenge for the management and prognosis of suspected patients. No study has been done on the detection of either viral or viral-bacterial co-infection among presumed pyogenic meningitis cases in Ethiopia. We, therefore, aimed to determine the distribution of cytomegalovirus (CMV) and human enteroviruses (HEVs) among patients with presumptive pyogenic meningitis at University hospitals in Ethiopia. METHODS: Viral nucleic acid was extracted from 86 repository CSF samples, which were collected from patients presumptively diagnosed with pyogenic meningitis between 2012 and 2013. PCR was done consecutively to investigate the possible viral etiologic agents of meningitis. RESULTS: HEVs were detected in 11 (12.8%) of the analyzed samples while none of the 86 samples were tested positive for CMV. Viral-bacterial co-infections were found among 4/11 (36.4%) confirmed cases. The majority of the patients (10/11) with HEVs were younger aged ≤ 19 years old. CONCLUSIONS: In this study, the magnitude of HEVs was shown to have a significant role in presumed pyogenic meningitis cases. Therefore, we recommend presumed pyogenic meningitis cases to be inspected for viral etiologies and improve meningeal symptoms interpretations.

Bacterial Profiles and Antimicrobial Susceptibility Pattern of Isolates from Inanimate Hospital Environments at Tikur Anbessa Specialized Teaching Hospital, Addis Ababa, Ethiopia.

INTRODUCTION: Microbial contamination of the hospital environment plays an important role in the spread of healthcare-associated infections (HCAIs). This study was conducted to determine bacterial contamination, bacterial profiles, and antimicrobial susceptibility pattern of bacterial isolates from environmental surfaces and medical equipment. METHODS: A cross-sectional study was conducted at Tikur Anbessa Specialized Hospital (TASH) from June to September 2018. A total of 164 inanimate surfaces located at intensive care units (ICUs) and operation theaters (OTs) were swabbed. All isolates were identified by using routine bacterial culture, Gram staining, and a panel of biochemical tests. For each identified bacteria, antibiogram profiles were determined by the Kirby-Bauer disk diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). RESULTS: Out of the 164 swabbed samples, 141 (86%) were positive for bacterial growth. The predominant bacteria identified from OTs and ICUs were Staphylococci aureus (23% vs 11.5%), Acinetobacter baumannii (3.8% vs 17.5%) and coagulase-negative Staphylococcus (CoNS) (12.6% vs 2.7%) respectively. Linens were the most contaminated materials among items studied at the hospital (14.8%). Gram-positive bacteria (GPB) had significantly high resistance levels to penicillin (92.8%), cefoxitin (83.5%), and erythromycin (53.6%). On the other hand, Gram-negative bacteria (GNB) revealed the highest resistance levels to ampicillin (97.5%), ceftazidime (91.3%), ceftriaxone (91.3%), and aztreonam (90%). However, a low resistance level was recorded for amikacin (25%) followed by Ciprofloxacin (37.5%). Of the 63 S. aureus isolates, 54 (85.7%) were methicillin-resistant S. aureus (MRSA). CONCLUSION: The inanimate surfaces and commonly touched medical equipment within OTs and ICUs are reservoirs of potentially pathogenic bacteria that could predispose critically ill patients to acquire HCAIs. The proportions of the antimicrobial resistance profile of the isolates are much higher from studied clean inanimate environments.

Enhanced identification of Group B streptococcus in infants with suspected meningitis in Ethiopia.

Meningitis is one of the top ten causes of death among Ethiopian infants. Group B streptococcus (GBS) has emerged as a leading cause of meningitis in neonates and young infants, resulting in high mortality. Despite this, there is no report on GBS associated meningitis in Ethiopia where infant meningitis is common. Hence, the aim of this study was to determine the proportion of GBS associated meningitis among Ethiopian infants. PCR was prospectively used to detect GBS in culture-negative cerebrospinal fluid (CSF) samples, which were collected from infants suspected for meningitis, at Tikur Anbessa specialized hospital, Ethiopia, over a one-year period. GBS was detected by PCR in 63.9% of culture-negative CSF samples. Out of the 46 GBS positive infants, 10.9% (n = 5) of them died. The late onset of GBS (LOGBS) disease was noted to have a poor outcome with 3 LOGBS out of 5 GBS positive samples collected from patients with the final outcome of death. PCR was advantageous in the identification of GBS in culture-negative CSF samples. GBS was detected in 64% of the CSF samples from infants with meningitis compared with zero-detection rate by culture.

Molecular studies of meningococcal and pneumococcal meningitis patients in Ethiopia.

Neisseria meningitidis infections in sub-Saharan Africa usually present with distinct symptoms of meningitis but very rarely as fulminant septicemia when reaching hospitals. In Europe, development of persistent meningococcal shock and multiple organ failure occurs in up to 30% of patients and is associated with a bacterial load of >106/ml plasma or serum. We have prospectively studied 27 Ethiopian patients with meningococcal infection as diagnosed and quantified with real-time PCR in the cerebrospinal fluid (CSF) and serum. All presented with symptoms of meningitis and none with fulminant septicemia. The median N. meningitidis copy number (NmDNA) in serum was < 3.5 × 103/ml, never exceeded 1.8 × 105/ml, and was always 10-1000 times higher in CSF than in serum. The levels of LPS in CSF as determined by the limulus amebocyte lysate assay were positively correlated to NmDNA copy number ( r = 0.45, P = 0.030), levels of IL-1 receptor antagonist, ( r = 0.46, P = 0.017), and matrix metallopeptidase-9 (MMP-9; r = 0.009). We also compared the inflammatory profiles of 19 mediators in CSF of the 26 meningococcal patients (2 died and 2 had immediate severe sequelae) with 16 patients with Streptococcus pneumoniae meningitis (3 died and 3 with immediate severe sequelae). Of 19 inflammatory mediators tested, 9 were significantly higher in patients with pneumococcal meningitis and possibly linked to worse outcome.

Investigation of correlates of protection against pharyngeal carriage of Neisseria meningitidis genogroups W and Y in the African meningitis belt.

BACKGROUND: Serum bactericidal antibody titres that correlate with protection against invasive meningococcal disease have been characterised. However, titres that are associated with protection against acquisition of pharyngeal carriage of Neisseria meningitidis are not known. METHODS: Sera were obtained from the members of a household in seven countries of the African meningitis belt in which a pharyngeal carrier of N. meningitidis had been identified during a cross-sectional survey. Serum bactericidal antibody titres at baseline were compared between individuals in the household of the carrier who became a carrier of a meningococcus of the same genogroup during six months of subsequent follow-up and household members who did not become a carrier of a meningococcus of this genogroup during this period. RESULTS: Serum bacterial antibody titres were significantly higher in carriers of a serogroup W or Y meningococcus at the time of recruitment than in those who were not a carrier of N. meningitidis of the same genogroup. Serum bactericidal antibody titres to a strain of N. meningitis of the same genogroup as the index cases were no different in individuals who acquired carriage with a meningococcus of the same genogroup as the index case than in those who did not become a carrier during six months of follow-up. CONCLUSION: Serum bacterial antibody titres to N. meningitidis of genogroup W or Y in the range of those acquired by natural exposure to meningococci of these genogroups, or with cross-reactive bacteria, are not associated with protection against acquisition of carriage with meningococci of either of these genogroups.

Correction: A Seroepidemiological Study of Serogroup A Meningococcal Infection in the African Meningitis Belt.

[This corrects the article DOI: 10.1371/journal.pone.0147928.].

A Seroepidemiological Study of Serogroup A Meningococcal Infection in the African Meningitis Belt.

The pattern of epidemic meningococcal disease in the African meningitis belt may be influenced by the background level of population immunity but this has been measured infrequently. A standardised enzyme-linked immunosorbent assay (ELISA) for measuring meningococcal serogroup A IgG antibodies was established at five centres within the meningitis belt. Antibody concentrations were then measured in 3930 individuals stratified by age and residence from six countries. Seroprevalence by age was used in a catalytic model to determine the force of infection. Meningococcal serogroup A IgG antibody concentrations were high in each country but showed heterogeneity across the meningitis belt. The geometric mean concentration (GMC) was highest in Ghana (9.09 µg/mL [95% CI 8.29, 9.97]) and lowest in Ethiopia (1.43 µg/mL [95% CI 1.31, 1.57]) on the margins of the belt. The force of infection was lowest in Ethiopia (λ = 0.028). Variables associated with a concentration above the putative protective level of 2 µg/mL were age, urban residence and a history of recent vaccination with a meningococcal vaccine. Prior to vaccination with the serogroup A meningococcal conjugate vaccine, meningococcal serogroup A IgG antibody concentrations were high across the African meningitis belt and yet the region remained susceptible to epidemics.

Prevalence and incidence of, and risk factors for, HIV-1 infection among factory workers in Ethiopia, 1997-2001.

The study was conducted to determine the prevalence, incidence, and risk factors for HIV infection among factory workers at two sites in Ethiopia. During February 1997-December 2001, a structured questionnaire was used for obtaining information on sociodemographics, sexual behaviour, and reported sexually transmitted infections (STIs) from a cohort of 1679 individuals. Serum samples were screened for antibodies against HIV, Treponema pallidum haemaglutination (TPHA), and herpes simplex virus type 2 (HSV-2). The overall baseline prevalence of HIV was 9.4%-8.5% among males and 12.4% among females. For both the sexes, the factors independently associated with an increased risk of HIV infection were widowhood and having had antibodies against TPHA and HSV-2. The risk factors specific for males were being orthodox Christian, having had a higher lifetime number of sexual partners, and genital discharge in the past five years. The risk factors for females, included low income, one or more rape(s) over lifetime, and casual sex in the last year. The overall incidence of HIV infection was 0.4 per 100 person-years. The highest rate of incidence was observed among young women aged less than 30 years (1 per 100 person-years). The study confirmed that high-risk sexual behaviour and STIs play major roles in the spread of HIV infection in the Ethiopians of both the sexes, but the factors, such as rape and low economic status, make women more vulnerable than men.

Herpes simplex virus type 2 seropositivity among urban adults in Africa: results from two cross-sectional surveys in Addis Ababa, Ethiopia.

BACKGROUND: Although several surveys investigating the epidemiology of herpes simplex virus type 2 (HSV-2) infection using type-specific immunologic assays have been carried out in Africa, none has examined the risk factors for HSV-2 infection in a representative sample from an urban adult population. GOALS: To estimate the prevalence of HSV-2 infection in the adult population of Addis Ababa, Ethiopia, and to identify risk factors for HSV-2 infection. STUDY DESIGN: Two cross-sectional surveys, one community-based (June to September 1996, n = 506) and one factory-based (February to November 1997, n = 657), were conducted. Samples were tested for HSV-2 immunoglobulin G antibodies using type-specific enzyme-linked immunoassays (ELISA). RESULTS: In the community-based survey, HSV-2 prevalence increased with age until 25 years, then leveled off at 50% in both genders. The same independent predictors of HSV-2 infection were identified in both genders: older age, higher lifetime number of sexual partners, positive HIV serology, and positive Treponema pallidum hemagglutination serology. CONCLUSIONS: This study confirmed the high prevalence of HSV-2 infection among adults in an African urban population and its association with HIV infection. Prevention of HSV-2 and other sexually transmitted infections through partner reduction and condom use should be encouraged.