The seroprevalance of Crimean-Congo haemorrhagic fever in people living in the same environment with Crimean-Congo haemorrhagic fever patients in an endemic region in Turkey.

Crimean-Congo haemorrhagic fever (CCHF) is endemic in Turkey, and since 2004 many cases have been reported from different regions of Turkey. There are limited data about the seroprevalence of the disease in household members of patients or persons sharing the same environment. We evaluated seroprevalence of CCHF in the immediate neighbourhood and in household members of patients living in the same environment as confirmed cases of CCHF in an endemic area of Turkey. A total of 625 healthy subjects [mean (s.d.) age: 42·3 (18·4) years, 58·7% females] without a past history of CCHF infection included in this case-control, retrospective study were evaluated in terms of sociodemographic characteristics, risk factors for CCHF via a study questionnaire, while serum analysis for CCHF virus (CCHFV) IgG antibodies was performed by ELISA. Anti-CCHFV IgG antibodies were positive in 85 (13·6%) participants. None of the seropositive individuals had a history of symptomatic infection. Regression analysis revealed that animal husbandry [odds ratio (OR) 1·84, 95% confidence interval (CI) 1·09-3·11], contact with animals (OR 2·31, 95% CI 1·08-5·10), contact with ticks (OR 3·45, 95% CI 1·87-6·46), removing ticks from animals by hand (OR 2·48, 95% CI 1·48-4·18) and living in a rural area (OR 4·05, 95% CI 1·65-10·56) were associated with increased odds of having IgG seropositivity, while being a household member of a patient with prior CCHF infection had no influence on seropositivity rates. This result also supports the idea that CCHF is not transmitted person-to-person by the airborne route.

The acquisition time of infection: a determinant of the severity of hepatitis C virus-related liver disease in renal transplant patients.

BACKGROUND: The aim of this study was to compare the clinical and histopathological course of HCV infection acquired before and during or after renal transplantation. METHODS: According to HCV status, 197 RT patients were divided into three groups. At the time of RT, anti-HCV antibody was positive in 47 patients (pre-RT HCV group). In 27 patients, in whom anti-HCV negative at the time of RT, anti-HCV and/or HCV RNA was found to be positive following an ALT elevation episode after RT (post-RT HCV group). Both anti-HCV and HCV RNA were negative at all times in remaining 123 patients (control group). RESULTS: Liver biopsy was performed in 31 of 47 patients in pre-RT and 24 of 27 in post-RT HCV group after RT. Duration of follow-up was similar in all groups with a mean of 7.1 +/- 4.0 yr. Ascites and encephalopathy were seen in only post-RT HCV group (22%). Histological grade (6.5 +/- 2.7 vs. 4.1 +/- 1.4) and stage (2.0 +/- 1.5 vs. 0.8 +/- 0.8) was significantly severe in post-RT HCV group (p < 0.01). Three patients died due to liver failure in post-RT HCV group. CONCLUSIONS: HCV infection acquired during or after RT shows a severe and rapidly progressive clinicopathological course, which is significantly different from pre-transplant anti-HCV positive patients.

Clinical significance of basal core promoter and precore mutations in chronic hepatitis B.

BACKGROUND/AIMS: The mutations in the basal core promoter and precore region of hepatitis B virus genome in hepatitis B e antigen-positive and -negative chronic hepatitis B patients have been described. The reports about their prevalence and clinical significance in the Mediterranean region where D is the predominant genotype, are very limited. METHODOLOGY: The serum samples were collected from 44 naive chronic hepatitis B patients. For detection of the mutations basal core promoter and precore regions of HBV genome were amplified and sequenced. RESULTS: All samples were determined as genotype D. Before initiation of treatment basal core promoter mutations were found as 55% (11/20) and 46% (11/24) in HBeAg-positive and -negative patients, respectively (p > 0.5). HBeAg-negative samples were associated with precore mutations (G1896A and G1899A). Three of 20 (15%) patients of HBeAg-positive and seven of 24 (29%) of HBeAg-negative populations showed sustained response to therapy at the 24th month of initiation. CONCLUSIONS: The presence of precore stop codon mutant in those with sustained response was 89%, overall at the end of therapy. At initiation of therapy basal core promoter mutations were more common in non-responders than responders (65% vs. 20%; p < 0.001). While 23% of cases totally showing sustained response, absence of mutations in the basal core promoter region of hepatitis B virus genotype D may be related to sustained response in patients with chronic hepatitis B.

Comparison of sequence analysis and INNO-LiPA HBV DR line probe assay in patients with chronic hepatitis B.

The aim of this study was to compare direct sequence analysis of partial HBV pol gene and Inno-LiPA HBV DR in serum samples of 120 chronic hepatitis B patients sent to the Clinical Microbiology Laboratory of Ege University Hospital because of lamivudine resistance. Sequence analysis was performed on ABI Prism 310 Genetic Analyzer. Comparison of Inno-LiPA and sequence results obtained by double-blind evaluation showed full agreement (both at rt180 and rt204) in 58.8% of samples. Visually rechecking of the electropherograms increased this rate to 68.3% Codon based rates are 81.7% and 75.8% at rt180 and rt204 respectively. LiPA detected variants in additional 12 (10%) samples, but missed one variant sample (both rt180 and rt204) and one sample was indeterminate due to poor probe binding. LiPA allows determination of mixed variants and seems to be more sensitive and simple for routine testing even though sequence analysis is still the gold standard for detecting new variants.

[Evaluation of the agreement of results obtained from ABI Prism 7000 and 7700 sequencers in the quantification of hepatitis B virus DNA]. / Hepatit B virus DNA kantitasyonunda ABI Prism 7000 ile 7700 sekans saptama cihazlarinin sonuçlarinin birbiri ile uygunlugunun arastirilmasi.

There are different methods and systems for quantification of HBV-DNA in clinical virology laboratories. The aim of this study was to evaluate the agreement of the polymerase chain reaction (PCR) protocol with ABI Prism 7000 instrument (PE Biosystems) which was designed and optimised for ABI Prism 7700 (PE Biosystems). Serum samples obtained from 168 chronic hepatitis B patients were treated with "High Pure Viral Nucleic Acid Kit" (Roche Applied Science, USA), and MagnaPure LC isolation station (Roche Applied Science, Germany) was used for HBV-DNA isolation. Real time PCR procedure which amplifies pre-S gene of HBV genome was performed. Amplification and detection steps of all samples were performed with ABI Prism 7700 and 7000 Sequence Detection Systems. Among 168 samples, results of 124 serum samples were found to be in dynamic ranges of the tests. The results of these 124 samples obtained from ABI 7000 and ABI 7700 were concordant. Among the rest of 44 samples; one yielded higher than 10(10) copies/mL with two of the systems; six samples gave results higher than 10(10) copies/mL only with 7700; thirty samples were found negative with both of the systems; seven samples were positive (320-1220 copies/mL) with 7000 but negative with 7700. As a result this PCR protocol can be used in ABI 7000 system according to viral quality control (VQC) results. However, since the results of samples with HBV-DNA less than 1 x 10(6) copy/ml were discordant with the results obtained by ABI 7700 system, it can be concluded that different systems must not be used for the management and monitoring of the same patient.

HBV vaccination in liver transplant recipients: not an effective strategy in the prophylaxis of HBV recurrence.

Anti-HBs immunoglobulins (HBIG) and lamivudine are main options to prevent hepatitis B virus (HBV) reinfection after liver transplantation. Although they are very effective, development of mutant viruses and high cost of treatment are main limitations for their application. Additionally there is an uncertainity for the duration of that prophylaxis regimen and its mostly applied indefinitely. Recently, post-transplant HBV vaccination is reported to be a cheaper alternative prophylaksis strategy, that enables discontinuation of HBIG. To investigate the efficacy of HBV vaccination in patients transplanted for HBV cirrhosis, we administered double course of double dose recombinant HBV vaccine (Genhavac B; containing HBV pre-S1, pre-S2, and S gene products). Vaccination has been started 1 month after HBIg discontinuation, and lamivudine (100 mg/day) was given throughout the study. The first cycle consisted of 0, 1- and 6-month schedule, and, in nonresponders, second cycle 0, 1-, 2-month schedule. Fourteen patients included into the study. Only one patient seroconverted (an anti-HBs titre of 37 IU/L) after the first cycle. No other patient responded to second cycle. HBV vaccination in the post-transplantation setting does not seems like an effective strategy in the prophylaxis of HBV recurrence.

Failure to detect Chlamydia pneumoniae DNA in cerebral aneurysmal sac tissue with two different polymerase chain reaction methods.

OBJECTIVE: Chlamydia pneumoniae (C pneumoniae) is a common cause of a usually mild, community acquired pneumonia. This organism, however, can spread from the respiratory tract into other parts of the body and has been detected in up to 70% of atheromatous lesions in blood vessels. Although the exact mechanism of the C Pneumoniae contribution to the pathogenesis of atherosclerosis remains unknown, prophylactic antibiotic trials are planned for people at high risk for coronary disease. METHOD: In this study the authors aimed to investigate C pneumoniae DNA content in the cerebral aneurysmal sac tissue with the aid of polymerase chain reaction (PCR) method. C pneumoniae DNA was searched in 15 surgically clipped and removed aneurysmal sac tissue and in two tumour (an ependymoma of the fourth ventricle and a craniofaringoma) samples by touchdown enzyme time release PCR (TETR PCR) targeting 16S rRNA gene and by nested PCR targeting ompA gene. RESULTS: Both PCR methods were sensitive to detect in C pneumoniae 4x10(-2) genomes. C pneumoniae DNA was not detected in any of the 17 sample tissues of these patients. CONCLUSION: The contribution of C pneumoniae in the development of intracranial aneurysms cannot be excluded despite the results of this study. Further studies on the possible role of C pneumoniae or any other micro-organisms in the pathogenesis of aneurysms should be performed.

Nosocomial hepatitis C virus infection in a renal transplantation center.

Nosocomial hepatitis C virus (HCV) infections were recorded in the renal transplantation unit of the university hospital. There were cases of acute HCV infection with aggressive clinical courses diagnosed from a positive HCV RNA test in the early post-transplantation period and which remained anti-HCV negative. Their anti-HCV seronegativity was attributed to them having acquired HCV under intense immunosuppressive therapy and suggested that the aggressive clinical course could be due to the deficient immune response resulting in an inability to limit viral replication. There were also donors diagnosed as having acute HCV infection in the early post-operative period. Genotyping and sequence analysis for HCV were performed on the isolates of eight of these patients who were consecutively transplanted and of three donors whose recipients were infected with HCV prior to transplantation, and who acquired acute HCV infection after transplantation. Of the eight recipients in the first group three were genotype 1a, three were genotype 1b, one was genotype 3a, and the last one was genotype 4 according to Simmond's classification. Of the three donor-recipient couples both the HCV isolates from one couple were genotyped as 1b and the phylogenetic analysis indicated that the patients were infected with a common variant of HCV, but the genotypes of HCV isolates from the other couples were different. Recipients were genotype 1b and the donors were genotype 1a in these couples. Genotype results of the first group and donor-recipient couples, and sequence analysis of genotype 1b and 1a isolates, showed that the source of infection was not a unique strain and there were multiple breaks in universal precautions while managing these patients.

TT virus infection and genotype distribution in blood donors and a group of patients from Turkey.

BACKGROUND: TT virus (TTV) DNA has been found in a large proportion of patients with different forms of non-A-G hepatitis, however the clinical importance is unclear. We aimed to determine the genotypes of TTV isolates found in blood donors and different patient groups from the western part of Turkey. MATERIALS AND METHODS: TT DNA was investigated in serum samples of 91 volunteer blood donors (BD), 105 thalassemia (TH) patients, ten patients with fulminant hepatitis (FH) and 16 hemodialysis (HD) patients by heminested PCR using primers NG059, NG061 and NG063 from the ORF1 region. 39 isolates were genotyped by analyzing the partial sequence of ORF1. RESULTS: TTV DNA was found in 75% of HD, 80% of FH, 61% of TH patients and in 51.6% of BD. Among the sequenced isolates, 14 (35.9%) belonged to genotype 1 (G1) and 25 (64.1%) belonged to genotype 2 (G2). Among the G2 sequences, 22 were grouped as G2c. CONCLUSION: TTV infection was common in the population studied, even with moderately sensitive primers. G2 was the major genotype of the studied population without any significant differences in distribution between various patient groups and BD.

Low-dose intramuscular hepatitis B vaccination in medical students: 4-year follow-up.

BACKGROUND: This is a report on the results of immunization of medical students with low-dose hepatitis B (HB) vaccine prior to starting clinical practice and evaluation of the efficacy of this vaccination scheme. MATERIALS AND METHODS: Low-dose (2 microg) recombinant HB vaccine was administered intramuscularly (im) at months 0, 1, 2 and 12 to 105 volunteers who wee HB surface antigen (HBsAg) and anti-HB core antigen (HBc) negative. Additional doses were administered after the third dose to the vaccines with anti-HBs titers below 10 IU/l. RESULTS: Protective anti-HBs levels (above 10 IU/l) were obtained in 73.3%, 95.6%, 100% and 92.8% of vaccines with geometric mean titers of 91, 61.6, 3,662 and 367 IU/l at months 3, 12, 13 and 44 months, respectively. CONCLUSION: Long-term effective protection against HB could be obtained in medical students with this scheme. Low-dose HB im vaccination can be utilized as a cost-saving vaccination strategy.

Diagnosis of hepatitis C virus (HCV) infection and laboratory monitoring of its therapy.

BACKGROUND: Just after the identification and characterization of hepatitis C virus (HCV) in 1989, tests for the detection of HCV antibodies or HCV RNA in serum were developed. The enzyme-linked immunosorbent assays (ELISAs) and confirmatory/supplemental analytical antibody tests were improved in sensitivity and specificity with the development of further generations of these assays. Application of molecular tests for detecting, quantifying, and characterization of the infecting virus became very important in management of HCV infection. OBJECTIVE AND DESIGN: This review summarizes the assays developed for the diagnosis and management of HCV infection. Strategies for the diagnosis and monitoring with the advantages and disadvantages of the assays based on the setting and goal are discussed according to data in the literature and our experience. RESULTS: Specific laboratory diagnostic tests for hepatitis C virus infection may be discussed under two titles: (i) Serological antibody tests which detect anti-HCV in serum or plasma; (ii) Molecular tests which detect HCV RNA genome, investigate viral load, and determine the characteristics of the genome. Strategies in different laboratory settings which screen populations with different HCV prevalences vary. CONCLUSIONS: Anti-HCV positive result in a low-risk setting such as blood banks should be confirmed with an analytical antibody test. Then a HCV RNA test should be performed on serum of the person with a positive or indeterminate confirmatory test result. On the contrary, anti-HCV positive test result in high-risk population or a situation where HCV infection is suspected, it is likely to be true positive and confirmation with HCV RNA test will be significant. Quantitative HCV RNA test and genotyping should be performed if therapy is considered.

Low-dose intradermal administration of recombinant hepatitis B vaccine in children: 5-year follow-up study.

Several studies have documented the efficacy of low-dose intradermal administration of hepatitis B vaccine. However, little is known about the duration of protection provided by low-dose intradermal administration of hepatitis B vaccine. This study reports results from a 5-year follow up period of 200 healthy children (100 infants and 100 preschool children) immunized intradermally with 2 microg doses of recombinant hepatitis B vaccine (GenHevac B) at months 0,1, and 6. In the 8th week after the third vaccine dose, 97% of the children developed anti-HBs antibodies higher than or equal to 10 mlU ml(-1), and the antiHBs geometric mean titre (GMT) was 676 mlU ml(-1). In month 18 and year 5, the anti-HBs GMT decreased to approximately one-third (220 mlU ml(-1)) and one-tenth (68 mlU ml(-1)) of the initial levels, respectively. However, 87% of the children had protective levels of anti-HBs (> or =10 mlU ml(-1)) after 5 years. Among 156 children followed for 5 years, none became positive for anti-HBc and/or HbsAg. Seven children who were seronegative after 5 years developed anti-HBs antibodies higher than 1000 mlU ml(-1) after an additional 10 microg intramuscular hepatitis B vaccine. Persistent immunologic memory over periods of 5 years or more is evident, the anamnestic antibody response to a booster dose of vaccine, even in these children who have lost antibody. We conclude that intradermal administration of 2 microg recombinant hepatitis B vaccine provides long-term protection against hepatitis B virus in infants and preschool children.

Clinicopathological features of rapidly progressive hepatitis C virus infection in HCV antibody negative renal transplant recipients.

BACKGROUND: Hepatitis C virus (HCV) infection acquired during dialysis treatment generally shows a relatively benign course after renal transplantation (RTx). However, less is known about the course of HCV infection acquired during or after RTx. METHODS: Clinical and histopathological assessment of 15 renal transplant recipients who acquired HCV infection during or after RTx. RESULTS: Alanine aminotransferase levels rose for the first time 1-19 weeks after RTx. HCV RNA was found positive in all patients, but anti-HCV became positive in only nine of them. During a mean follow-up of 21 +/- 12 months, jaundice appeared in 12 patients while ascites and/or hepatic encephalopathy occurred in six. Azathioprine was stopped in all patients. Cyclosporin was also stopped in four patients and in two of them prednisolone was also interrupted for a period of 3-7 weeks. Following this, ascites, hepatic encephalopathy and biochemical disturbances improved, while no deterioration was seen in graft function. Nine of the 15 patients had undergone two consecutive liver biopsies (LB). The first LB revealed cirrhosis in three and chronic hepatitis in six patients; the second LB showed cirrhosis in seven patients. The histological activity index (Knodell's score) progressed from 11.8 +/- 3.5 to 13.8 +/- 3.8. CONCLUSIONS: The results suggest that HCV infection acquired during or after RTx may run an unusual and rapidly progressive clinical and histopathological course at least in some of these patients. Decrease or withdrawal of immunosuppressive drugs may improve early hepatic failure without detrimental effect on graft function during that period.

Screening for human immunodeficiency virus type 1 and 2 in a Turkish blood donor population.

OBJECTIVES: To determine the prevalence of human immunodeficiency virus-1 and -2 infection in voluntary blood donors at a university hospital in the third largest city of Turkey and to evaluate the HIV testing strategy for notifying blood donors. METHODS: Between July 1995 and August 1997, 36,373 voluntary blood donors who met the criteria for donating blood were tested for the presence of HIV-1 and -2 antibodies by using an automated enzyme-linked fluorescent immunoassay. Repeatedly reactive samples were subjected to a different enzyme-linked immunosorbent assay (ELISA) and a line immunoassay (LIA) for the detection of antibodies. RESULTS: Of the 36,373 samples tested 72 were found to be repeatedly reactive or borderline by the first screening enzyme immunoassay (EIA). None of the 72 samples was reactive by the second EIA. These samples were further tested by LIA: 64 were negative on the line immunoassay and 8 were indeterminate. Three of eight donors who had indeterminate results by LIA were tested for HIV-1 DNA by polymerase chain reaction (PCR) and were found to be negative. One additional donor with an indeterminate LIA was found to be negative by EIA and LIA during the 6-month follow-up period. CONCLUSION: Donor questioning, repeat EIA testing, LIA testing, and HIV-1 DNA analysis did not confirm evidence for HIV infection among this blood donor population. Blood donor notification of test results according to the World Health Organization (WHO) strategy III was found to be an appropriate approach.

Low-dose intradermal versus intramuscular administration of recombinant hepatitis B vaccine: a comparison of immunogenicity in infants and preschool children.

Two hundred infants and two hundred preschool children were randomly assigned to receive either 10 micrograms of recombinant hepatitis B vaccine (GenHevac B) intramuscularly (i.m.) or 2 micrograms intradermally (ID) in the deltoid region at 0, 1 and 6 months. Antibody to hepatitis B surface antigen (anti-HBs) was tested eight weeks after the third vaccine dose. Standard dose i.m. and low-dose ID administration of recombinant hepatitis B vaccine produced comparable rates of anti-HBs equal to or higher than 10 mIU ml-1 in infants (98% and 94%, respectively) and preschool children (98% and 100%, respectively). Although i.m. vaccination produced higher anti-HBs concentrations than ID vaccination both in infants (geometric mean titre-GMT, 935 versus 621 mIU ml-1) and preschool children (GMT, 1393 versus 804 mIU ml-1), the differences were not statistically significant (p > 0.05). The preschool children tended to have higher anti-HBs concentrations than the infants. No clinically serious adverse effects were observed in both vaccine groups; however, induration and hyperpigmentation at the injection site were more often seen in the study population that was vaccinated intradermally. We conclude that intradermal administration of 2 micrograms recombinant hepatitis B vaccine is safe and effective in infants and preschool children, and may be an acceptable, less expensive alternative to full-dose i.m. vaccination for mass immunization, especially in developing countries.

Intradermal administration of hepatitis B vaccine in infants and preschool children.

One of the ways to administrate hepatitis B vaccination is the intradermal (id) route. The aim of this study is to evaluate the immunologic response of various age groups of children who received three 2 micrograms id doses of recombinant hepatitis B vaccine. One hundred and eighty-seven children (86 infants, 101 preschool children) were administered a 2 micrograms dose of recombinant hepatitis B vaccine (Gen Hevac B) intradermally zero, one and six months. Eight weeks after the third vaccination, the geometric mean titers (GMT) of antibody to hepatitis B surface antigen (anti-HBs) of infants was 753 IU/L; that of preschool children was 799 IU/L. There was no statistically significant difference between the anti-HBs GMT of infants and preschool children. However, infants were less likely to have developed protective anti-HBs (< or = 10 IU/L) than preschool children (93% vs 100%, p = 0.009). In 8.1 percent of infants and 3.9 percent of preschool children, local reactions were observed. The 2 micrograms recombinant vaccine by id route is safe and suitable for immunization of preschool children. The id route is technically difficult to administrate in infants and protective seroconversion rates are lower than in preschool children.

DNA insitu hybridization in the diagnosis of human papillomavirus infection.

BACKGROUND: Certain types of human papillomavirus (HPV) are shown to be associated with the development of genital lesions. DNA hybridization methods are used for the diagnosis of HPV infections. OBJECTIVE: To use a nonradioactive DNA in situ hybridization system for the investigation of HPV infections responsible for the development of genital lesions in women. STUDY DESIGN: Sections from archival paraffin embedded biopsy specimens of 59 cases were screened for the presence of HPV DNA sequences by using digoxigenin labeled DNA probe which is specific for all types of HPVs and digoxigenin detection system. The study group consisted of samples diagnosed as squamous hyperplasia of the vulva (group 1), koilocytosis (group 2), condyloma acuminatum/koilocytotic atypy (group 3), cervical intraepithelial neoplasia (CIN), and epidermoid carcinoma (group 4). RESULTS: No HPV DNA was detected in groups 1 and 2 which consisted of 3 and 13 specimens respectively. Seven of 11 (63.6%) specimens in group 3 and 7 of 32 (21.9%) in group 4 were found to be positive for in situ HPV DNA. Seven positive samples in group 3 and one positive sample in group 4 were typed as HPV 6/11. Five samples of the remaining positives in group 4 were typed as HPV 16/18. One case was found to be positive with both 16/18 and 31/33. CONCLUSION: Nonradioactive DNA in situ hybridization is an easy and efficient method to be performed for the diagnosis of HPV infections. Koilocytosis with atypy is directly correlated with HPV infection and it is suggested to monitor the CIN cases with HPV type 16/18 infection since the pathology can be progressive.

Serological and nucleic acid analyses for HIV and HTLV infection on archival human plasma samples from Zaire.

In order to better understand the genomic diversity and molecular phylogeny of the human retroviruses, the plasmas from 250 Zairean patients collected in 1969 were tested for antibodies to human T-cell lymphoma and human immunodeficiency viruses (HTLV or HIV) using ELISA and confirmatory Western blots and for viral nucleic acids by reverse transcriptase-directed PCR (RT-PCR). Interestingly, none of the patients was confirmed positive for HIV, even though this region is now endemic for HIV-1. However, 74 (30%) and 3 (1%) of the samples were positive for antibodies to HTLV-I and II, respectively. Forty-four of 74 (59%) Western blot-positive Zairean samples were RT-PCR positive for HTLV-I, while 1 of 3 (33%) of HTLV-II-seropositive samples was RT-PCR positive. On the contrary, none of the Western blot-negative or indeterminate samples were RT-PCR positive for either HTLV-I or HTLV-II. We have cloned and sequenced 140 bp of the pol gene flanked by SK110/SK111 from 8 HTLV-I- and 1 HTLV-II-positive archival samples from Zaire. The HTLV-I isolates from Zaire cluster together as a phylogenetic group, diverging from the prototype Japanese HTLV-I (ATK) by a range of 1.4 to 3.6%. Their close homology to some African STLV-I isolates suggests relatively recent interspecies transmission. The Zairean HTLV-II isolate is closely grouped with the HTLV-II substrain of isolates found in Paleo-Amerindians of the New World, making it unlikely that it represents an endemic African strain.