Mantle Sources of Recent Anatolian Intraplate Magmatism: A Regional Plume or Local Tectonic Origin?

We present an extensive study of rehomogenized olivine-hosted melt inclusions, olivine phenocrysts, and chromian spinel inclusions to explore the link between geodynamic conditions and the origin and composition of Pliocene-Quaternary intraplate magmatism in Anatolia at Kula, Ceyhan-Osmaniye, and Karacadag. Exceptional compositional variability of these products reveals early and incomplete mixing of distinct parental melts in each volcanic center, reflecting asthenospheric and lithospheric mantle sources. The studied primitive magmas consist of (1) two variably enriched ocean island basalt (OIB)-type melts in Kula; (2) both OIB-type and plume mid-ocean ridge basalt (P-MORB)-like melts beneath Toprakkale and Üçtepeler (Ceyhan-Osmaniye); and (3) two variably enriched OIB-type melts beneath Karacadag. Estimated conditions of primary melt generation are 23-9 kbar, 75-30 km, and 1415-1215 °C for Kula; 28-19 kbar, 90-65 km, and 1430-1350 °C for Toprakkale; 23-18 kbar, 75-60 km, and 1400-1355 °C for Üçtepeler; and 35-27 kbar, 115-90 km, and 1530-1455 °C for Karacadag, the deepest levels of which correspond to the depth of the lithosphere-asthenosphere boundary in all regions. Although magma ascent was likely facilitated by local deformation structures, recent Anatolian intraplate magmatism seems to be triggered by large-scale mantle flow that also affects the wider Arabian and North African regions. We infer that these volcanics form part of a much wider Arabian-North African intraplate volcanic province, which was able to invade the Anatolian upper plate through slab gaps.

The effects of genital schistosoma haematobium on human papillomavirus and the development of cervical neoplasia after five years in a Zimbabwean population.

BACKGROUND: High-risk human papillomavirus (HPV) is responsible for cervical cancer and genital Schistosoma haematobium infection has been hypothesized to be an additional co-factor or even an independent risk factor for cervical neoplasia. The present study aimed to investigate the impact of schistosomiasis on HPV persistence and development of cell atypia in a group of rural Zimbabwean women with confirmed high-risk HPV. METHODS: A five-year follow-up was done among women previously included in a study on genital schistosomiasis. Women who had high-risk HPV at baseline were invited after 5 years for examination of cell atypia, genital schistosomiasis, and high-risk HPV. Both vaginal lavage samples (low-cost) and cervix brush samples (high-cost) were obtained for further analysis. RESULTS: Thirty-seven women were re-examined. Genital Schistosoma haematobium of a minimum of five years' duration was associated with the development high-grade squamous intraepithelial neoplasia, but not with persistent high-risk HPV. There was a high concordance between the brush and vaginal lavage (96.3% agreement, kappa 0.93); however, the number of beta-globin negative vaginal lavage samples was unacceptably high. CONCLUSIONS: Findings warrant an exploration in a larger longitudinal study where a vaginal swab should be explored.

Human immunodeficiency virus, smoking and self-rated health in Harare, Zimbabwe.

SETTING: Twenty-two urban factories in Harare. OBJECTIVE: To determine the relationship between the human immunodeficiency virus (HIV), smoking and self-rated health in a high HIV prevalence urban workforce. DESIGN: Cross-sectional survey. RESULTS: Of 7482 employees, 6111 (82%) consented to interview and anonymous HIV serology; 88% were male; median age was 34 years. HIV prevalence was 19%. Current (median 6 cigarettes per day) and former smoking were reported by 17% and 7%, respectively. Smoking (current or former) was more common among HIV-positive (27%) than -negative participants (17%; P < 0.001). Factors significantly associated with being a smoker on multivariate analysis were being HIV-infected (OR 1.5, 95% CI 1.4-1.7), older age (P < 0.001), non-Christian (OR 1.6, 95% CI 1.2-2.2) and manual job (OR 1.4, 95% CI 1.2-1.6). Women (OR 0.05, 95% CI 0.03-0.11) and the better educated (OR 0.7, 95% CI 0.5-0.9) were significantly less likely to smoke. HIV-positive smokers had the highest risk of reporting poor health (adjusted OR compared to HIV-negative non-smokers 3.4, 95% CI 2.3-5.0). CONCLUSIONS: Smoking was significantly more common among HIV-positive than -negative employees in this predominantly male workforce. There was evidence of a combined effect on self-rated poor health, a variable shown to be a strong independent predictor of mortality in industrialised countries. Interventions to encourage smoking cessation may be an important component of HIV care in Southern Africa.

Impact of HIV infection on meningitis in Harare, Zimbabwe: a prospective study of 406 predominantly adult patients.

OBJECTIVE: To determine the causative organisms and characteristics of patients presenting with features of meningitis. DESIGN: A prospective cross-sectional study. SETTING: Two tertiary university-affiliated hospitals in Harare, Zimbabwe. PATIENTS: Four-hundred and six patients clinically suspected to have meningitis. MAIN OUTCOME MEASURES: Causative organisms of meningitis; clinical and cerebrospinal fluid characteristics. RESULTS: Four-hundred and six predominantly adult (95% were aged > or = 18 years) patients were suspected to have meningitis. Of the 200 patients confirmed to have meningitis, 89 (45%) had cryptococcal meningitis (CM), 54 (27%) had mononuclear meningitis (MM), 31 (16%) had pyogenic meningitis (PM), 24 (12%) had tuberculous meningitis (TBM) and 2 (1%) had undefined meningitis. HIV seropositivity was 100% in CM, 83% in MM, 81% in PM and 88% in TBM patients. In-hospital mortality rate was 38.8% for CM, 34.9% for MM, 68% for PM and 66.7% for TBM. HIV seropositivity was 80% in the 206 patients not found to have meningitis. CONCLUSIONS: All patients suspected to have meningitis had a high HIV sero positivity irrespective of whether they were later confirmed to have meningitis or not. CM was the most common type of meningitis seen. In-hospital mortality was high irrespective of the cause of meningitis.

Community-acquired bacteremia in human immunodeficiency virus-infected children in Harare, Zimbabwe.

BACKGROUND: HIV infection is common in mothers and their children in Zimbabwe, and HIV-infected children are particularly susceptible to bacterial infections. There is little information on the etiology and outcome of HIV-related bacteremia in African children. METHODS: Blood cultures from 309 hospitalized children in Zimbabwe, of whom 168 were diagnosed as having HIV, were examined for pathogens. The association among significant bacteremia, HIV infection and mortality was assessed in these children. RESULTS: The most common isolates were coagulase-negative staphylococci (31 children, 25 clinically significant), Staphylococcus aureus (22 children) and Streptococcus pneumoniae (20 children). Nontyphoidal Salmonella (10 children), Escherichia coli (4 children) and Klebsiella sp. (4 children) were the most frequent Gram-negative bacteria. Two children had Rhodococcus equi pneumonia. HIV-infected children showed increased risk of bacteremia (odds ratio (OR) = 2.68), especially if younger than 18 months of age (OR = 2.94), and high risk of enterobacteremia (OR = 15.76). There was no significant association of bacteremia with nutritional status. Mortality was 17% overall but was higher in HIV-infected children up to 6 months of age (OR = 2.81) and in bacteremic children of any age (OR = 2.03). CONCLUSIONS: Prompt recognition of pathogens and early administration of appropriate antimicrobials is important in reducing the morbidity and mortality associated with bacteremia in HIV-infected children in Africa.

PIP: Researchers compared data on 168 HIV-positive pediatric patients with data on 141 HIV-negative pediatric patients to examine the etiology and outcome of HIV-related bacterial infections in a pediatric population admitted to Harare Hospital in Zimbabwe during June 1993 to December 1994. The age of the children ranged from less than 1 month to 96 months. 72% were less than 12 months old. 54% of all pediatric patients tested were HIV-infected. HIV-infected children were more likely to have a bacterial infection than HIV-negative children (40% vs. 20%; odds ratio [OR] = 2.68; p 0.001). The difference in the bacterial infection rate was only significant for children aged less than 18 months (41% vs. 19%; OR = 2.94; p 0.001), however. 14% of the children suffered from severe malnutrition. Nutritional status was not significantly associated with bacterial infection. In both HIV-positive and HIV-negative children, Staphylococcus aureus was the most frequent bacterial pathogen (29% for HIV-positive and 18% for HIV-negative children). Many Gram-positive and Gram-negative isolates were resistant to the combination therapy of trimethoprim-sulfamethoxazole. Only 1 child, who was HIV-positive, had more than one bacterial infection (both Streptococcus pneumoniae and Actinomyces israelii). HIV-positive children were more likely to have an enterobacterial infection than HIV-negative children (10% vs. 0.7%; p 0.001). Mortality was significantly higher among HIV-infected children aged less than 6 months old than their HIV-negative counterparts (28% vs. 12%; OR = 2.81; p 0.05). Even though it was also higher among HIV-positive children aged more than 6 months (17% vs. 7%), the difference was not significant. Regardless of HIV status, children with bacteremia were more likely to die than those without bacteremia (24% vs. 14%; OR = 2.03; p 0.05). These findings stress the importance of early and effective antibiotic therapy. This therapy will reduce the morbidity and mortality associated with bacteriemia in HIV-infected children in Africa.

Severe Klebsiella infection as a cause of mortality in neonates in Harare, Zimbabwe: evidence from postmortem blood cultures.

Postmortem blood cultures were taken from 105 neonates dying at Harare Hospital during a 1-year period. The infants were characterized by prematurity (63% < 37 weeks gestation), low birth weight (60% < 2500 g) and low Apgar score at 1 min (43% < 3). More than one-half of the infants died within 48 hours of admission. Positive blood cultures within 10 minutes of death occurred in 44% of infants, and Klebsiella sp. were by far the most common isolates. Positive blood cultures were associated with very low birth weight (< 1500 g), and with babies who survived for > 48 hours. Antibodies to human immunodeficiency virus type 1 were found in 40% of the infants, and a high proportion of these had Klebsiella bacteremia. Nearly all the infants had received antibiotic therapy, usually penicillin and gentamicin. Very few babies who had received a cephalosporin had a positive blood culture, and in vitro tests showed that although many organisms were resistant to penicillin and the aminoglycosides, very few showed resistance to the cephalosporins. Our findings suggest that cephalosporins may be useful in treating severe neonatal sepsis, particularly when there is no response to more standard therapy.

Serodiagnosis of Trichomonas vaginalis infection by the indirect fluorescent antibody test.

The indirect fluorescent antibody test was used to detect antibodies to Trichomonas vaginalis in 200 antenatal patients. A total of 104 (52%) gave a positive reaction with antigen prepared from cultures of trichomonas isolated from seven of the patients. Antitrichomonal antibody was detected at a 1/4 dilution in 90% of patients with proven trichomoniasis, while the highest dilution at which antibody was detected was 1/32. IgG rather than IgM appeared to be the antibody class involved. Of those patients with no demonstrable trichomonal infection, 17% gave positive reactions at 1/4 dilution, while 64% had no demonstrable antibody. One of 30 children under 11 years of age gave a positive reaction.

Comparison of four techniques for the routine diagnosis of Trichomonas vaginalis infection.

Specimens from 495 patients attending Johannesburg hospitals and family planning clinics were examined for Trichomonas vaginalis by microscopy of Giemsa (GS), Papanicolaou (PAP), and acridine-orange (AO) stained smears, and by culture in Feinberg-Whittington medium. Culture, Pap and GS stained smears from vaginal swabs yielded fewer positives than AO stained smears. Although Pap-stained cytological smears gave the highest number of positives, in 30% of these cases the presence of T.vaginalis could not be confirmed by examination of vaginal swabs. Of the positive AO-stained smears, 93% were also positive by at least one other technique.

Single-dose metrifonate for the treatment of Schistosoma haematobium infection in an endemic area of Zimbabwe.

The excretion of Schistosoma haematobium eggs by school children in an endemic area of Zimbabwe was studied for 16 weeks following a single oral dose of 10 mg/kg body weight metrifonate. By 16 weeks, 40.7% of the children had ceased excreting eggs. The mean reduction in egg excretion was 75.1%, but over half the children showed a greater than 90% reduction. Of the treatment failures, the majority showed less marked or transient reductions in egg excretion, though evidence suggested that 17.5% of the failures may have been due to reinfection.

Eighteen-month follow-up on the treatment of urinary schistosomiasis with a single dose of metrifonate.

Egg excretion of school children with urinary schistosomiasis treated with a single 10 mg/kg dose of metrifonate was monitored over a period of 18 months. At 18 months 68.8% of infected children showed a greater than 90% reduction in egg excretion and 23.7% had ceased excreting eggs. During the study period 25% of children with no evidence of infection at the start of the trial had become infected, while 45.5% of children apparently cured by the metrifonate treatment had recommenced egg excretion. The evidence suggested that reinfection rather than recovery of adult worms was responsible. Children with scanty or light infections, in general, showed increasing egg excretion rates during the following period, while those with heavy or severe infections showed a sustained reduction. In view of this, single dose metrifonate may be a useful approach to mass treatment in a schistosomiasis control program, resulting in significant reduction in egg excretion in those most likely to be important sources of transmission.

Epidemiology of Giardia lamblia infection in children: cross-sectional and longitudinal studies in urban and rural communities in Zimbabwe.

Stool specimens from 3,038 children in rural and urban areas near Harare were examined for Giardia lamblia cysts. Preliminary studies, using specimens collected on three consecutive days from 157 known cyst passers, showed that over 89% of infections could be diagnosed on single stool specimens by examination of Gomori-stained smears. The overall prevalence of giardial infection was 19.4% with significantly more urban children (21.1%) passing cysts than rural children (16.7%). In urban areas the highest prevalence was in young (5-6 year) children, while in rural areas, the highest prevalence was in older (9-10 year) children. Of 132 children treated with Entamizole a metronidazole-diloxanide combination, 127 (96.2%) had ceased excreting cysts by the fifth treatment day. Follow-up examination of these children showed a high rate of reinfection, with 29.6% excreting cysts during the year following treatment. During the same period 13.3% of previously uninfected children had started passing cysts, while over half of infected, but untreated, children had undergone apparent "self-cure." Younger children were more likely to be reinfected than older children, and continued excreting cysts for a longer period of time.

Species-specific BALB/c mouse antibodies to rickettsiae studied by western blotting.

BALB/c mice were inoculated intraperitoneally either once only, or up to four times at weekly intervals, with viable Rickettsia rickettsii, Rickettsia conorii or the Israeli spotted fever group rickettsia. Sera collected one week after the last inoculation were tested for the presence of antibodies reactive with the above organisms by indirect fluorescent antibody testing and Western blot. With repeated inoculations there was a general progressive rise in homologous and heterologous immunofluorescence titers although the increase after the first inoculation was always the greatest. For each rickettsia, the homologous titers were higher than the heterologous titers. Western blots showed that the reactive antibodies were against rickettsial high molecular mass species specific protein antigens and homologous species-specific antibody reactions were detectable earlier than heterologous cross-reacting antibody reactions. Antibodies in mice sera did not react with the group specific lipopolysaccharide-like antigens of the rickettsiae although such reactivity was strong in Western blots with sera from patients suffering from acute Rickettsia conorii infections. Our findings suggest that the intraperitoneal route of inoculation of BALB/c mice can be used for the differentiation of spotted fever group rickettsiae.

Antimicrobial susceptibility patterns amongst group B streptococci from women in Harare, Zimbabwe.

As part of a larger study of vaginal pathogens in women in Harare, we have examined the antimicrobial susceptibility patterns of 130 isolates of group B streptococci (GBS). These organisms are important because of their association with preterm labour, premature rupture of membranes and neonatal sepsis. All of the isolates in Harare were fully sensitive to beta-lactams, with an MIC(90) for ampicillin of 0.38 mg/l, but five isolates were resistant in vitro to erythromycin, and each of these had an MIC >4 mg/l. Seven isolates showed resistance to clindamycin. Some isolates showed an intermediate sensitivity to gentamicin, but the great majority were resistant to this antibiotic. Studies in developed countries have shown that an intervention strategy, using intrapartum chemoprophylaxis, is effective in reducing the incidence of complications of GBS colonization in pregnant women. Our data suggest that ampicillin would be a suitable antibiotic for use in an intervention programme of intrapartum chemoprophylaxis in Harare.

Antimicrobial resistance in gonococci isolated from patients and from commercial sex workers in Harare, Zimbabwe.

The objective is to compare antibiotic resistance amongst gonococci isolated from different patient groups in Harare, Zimbabwe. Antimicrobial susceptibilities of Neisseria. gonorrhoeae were determined by disc sensitivity tests. The MICs for penicillin, kanamycin, ceftriaxone, norfloxacin and ciprofloxacin were determined using E-test strips. There were 147 isolates from symptomatic men, 47 isolates from symptomatic women, 29 isolates from asymptomatic women and 41 isolates from female commercial sex workers. A total of 119 (45%) isolates were PPNG and 23 (16%) non-PPNG isolates had a penicillin MIC > 0.64 mg/l. Over 90% of isolates were resistant to TMP/SMX and 16% were resistant to tetracycline. Resistance was uncommon against kanamycin (6%), erythromycin (2%) or ceftriaxone ( < 1%). For kanamycin, the MIC90 was 32 mg/l, for ceftriaxone the MIC90 was < 0.032 mg/l for non-PPNG and < 0.064 mg/l for PPNG. For norfloxacin and ciprofloxacin the MIC90 was < 0.064 mg/l for both PPNG and non-PPNG. Isolates from the commercial sex workers showed a significantly increased prevalence of PPNG, of penicillin-tolerant non-PPNG and of tetracycline resistance. Four of the 41 isolates from sex workers showed multiple resistance (to penicillin, TMP/SMX, tetracycline and kanamycin) compared to 1/223 isolates from other groups (OR = 24.0). Antimicrobial resistance is common amongst gonococci in Harare, especially with isolates from commercial sex workers. In order for STD treatment to be implemented as an effective strategy in HIV control, continued monitoring of resistance patterns is essential.

Isolation of spotted fever group rickettsias from triturated ticks using a modification of the centrifugation-shell vial technique.

A modification of the centrifugation-shell vial technique was used to isolate spotted fever group (SFG) rickettsias from triturated ticks which had previously been stored at -80 degrees C for up to 7 months. SFG rickettsias were successfully isolated in Vero cells from all 7 haemolymph positive ticks (Amblyomma hebraeum) used in the experiment. Attempts were also made to use these tick triturates to establish SFG rickettsial infections in tissue culture. Vero cells were used for 5 of the tick triturates and human embryonic lung cells (HEL) for the remaining 2. Infections were successfully established in 4 of the 5 Vero cell cultures, but in none of the HEL fibroblast cultures.

Piped water supply and intestinal parasitism in Zimbabwean schoolchildren.

The prevalence of intestinal parasitism in primary schoolchildren in three areas, communal (peasant farm) lands, commercial farms and urban townships, was assessed by examination of concentrated and stained stool specimens to determine the effect of water supply on intestinal parasitism. Piped water in communal lands was associated with decreased frequency of schistosomiasis and hymenolepiasis, but not with decreased frequency of protozoa. Schistosomiasis was very common in commercial farm labour communities, particularly on farms adjoining the local river, despite the availability of stored borehole water supplied through communal taps. The prevalence of intestinal parasitism in children from urban areas with municipal water supplied to taps in each household was similar to that of children in communal areas who obtained water from surface streams. The frequency of Giardia lamblia infection was higher in urban than in rural schoolchildren, and within communal areas was higher in children with access to protected borehole water. The provision of piped water was, therefore, not found to be associated with reduced prevalence of intestinal parasitism, though additional factors such as frequency of contact with infected water, the provision of ancillary improvements and the actual usage of available water supplies would need to be more closely assessed.

Serological diagnosis of neurocysticercosis: evaluation of ELISA tests using cyst fluid and other components of Taenia solium cysticerci as antigens.

An ELISA system was developed to assist with the diagnosis of neurocysticercosis. Antigens were prepared from the fluid, the protoscolex and the cyst wall of cysticerci dissected from infected pigs. The fluid antigen was tested both fresh and after freeze-drying and one year's storage. Sera from patients with proven neurocysticercosis were most reactive using the fluid and least reactive using the cyst wall antigens. Freeze-drying and prolonged storage of fluid antigen did not reduce its reactivity and repeated testing of sera with this antigen gave optical density values within 15% of the original value. Using this ELISA system positive results were obtained from all patients with active neurocysticercosis. Sera from patients with calcified cysts were usually non-reactive or marginally reactive to the fluid antigen.

Fatal Pneumocystis carinii pneumonia in HIV-seropositive infants in Harare, Zimbabwe.

Lung biopsies taken post mortem from 24 HIV-seropositive children who died of pneumonia in Harare Hospital (Zimbabwe) during 1995 were examined for pathogens using histology, culture, microscopy and polymerase chain reaction (PCR). Pneumocystis carinii was detected in 16 (67%) children, in 5 of whom bacterial pathogens were also detected. There were 2 cases of cytomegalovirus infection. On the basis of histology and PCR, none of the children had tuberculosis. These data add to the evidence that P. carinii pneumonia may be a significant cause of death in HIV-infected children in southern Africa. Policies on treatment for severe pneumonia, and on prophylaxis for children born to HIV-seropositive mothers need to be re-examined.

High prevalence of Enterocytozoon bieneusi infections among HIV-positive individuals with persistent diarrhoea in Harare, Zimbabwe.

Infection with the microsporidian parasite Enterocytozoon bieneusi may be a major cause of prolonged diarrhoea in individuals also infected with human immunodeficiency virus (HIV). The parasite has been reported from Europe, Australia and the Americas, with a prevalence of 7-29%. Faecal specimens were obtained from 202 adults and 106 children in Harare, Zimbabwe, all of whom were in hospital and had diarrhoea. HIV serology was available for 119 adults: 106 were HIV seropositive. There were clinical grounds for suspecting HIV infection in 23 of the remaining patients. E. bieneusi was identified in specimens from 13/129 patients (10%) for whom HIV infection was indicated by serology and/or clinical signs, 1/60 patients (2%) of uncertain HIV status, and 0/13 seronegative patients. 18/106 children were HIV seropositive and 12 were not; HIV serology was not available for the remainder, but 19 were strongly suspected of being infected with HIV on clinical criteria. E. bieneusi was not detected in samples from any child. As is common in Zimbabwe, the prevalence of other parasites in faecal specimens was low and, amongst patients with proven or suspected HIV infection, E. bieneusi was the most prevalent parasite identified, particularly in patients with diarrhoea of over 4 weeks duration.

Helicobacter pylori in endoscopy patients in Zimbabwe: value of enzyme-linked immunosorbent assay and a rapid urease test.

Biopsy and serum specimens were obtained from 95 patients undergoing endoscopy at the University of Zimbabwe Medical School. Common presenting features were epigastric pain, bleeding and dyspepsia. Ulcers were detected in 16 patients (17%), and were more common in men (24%) than in women (7%). Histological examination of biopsies showed that all 95 patients had spiral-shaped organisms that were indistinguishable microscopically from Helicobacter pylori, though the numbers of organisms varied considerably. There was evidence that the degree of inflammation in the mucosa was related to the numbers of H. pylori-like organisms (HPLO) present. Fifty-one biopsy specimens (55%) gave a positive rapid urease test (RUT), with colour change occurring within 4 h. In all but one case, the gastric mucosa from these patients contained moderate to numerous HPLO. We defined the 'gold standard' of H. pylori-associated gastritis as the presence of both moderate to numerous HPLO and moderate to severe inflammation in the gastric mucosa. Using these criteria, RUT had a sensitivity of 67% and a specificity of 68%. Sera from 92 patients were tested for immunoglobulin G antibodies reactive with a glycine-extract antigen of H. pylori, using an enzyme-linked immunosorbent assay (ELISA). Sera giving an indeterminate reaction in the ELISA were also tested by Western blotting. In all, 36 sera (39%) gave a positive ELISA or Western blot reaction. There was poor correlation between serology and RUT results, with only 57% of biopsy specimens from seropositive patients giving a positive RUT, compared with 45% from seronegative patients. Positive serology was found in only 35 patients (61%) with histological evidence of H. pylori-associated gastritis, and the specificity of the test was only 54%. When used in combination with the RUT result, however, 79% of patients with a positive RUT and positive serology had histological evidence of H. pylori-associated gastritis. There was a general trend for increased seroprevalence in patients with mild to moderate atypia. These findings indicate that serology, using an antigen derived from the type strain of H. pylori, is unreliable in detecting H. pylori infection in Zimbabwe. Current studies are aimed at characterizing antigens from organisms isolated from Zimbabwean patients.