Study of enteric pathogens among children in the tropics and effects of prolonged storage of stool samples.

The study was performed to compare real-time PCR after nucleic acid extraction directly from stool samples as well as from samples stored and transported on Whatman papers or flocked swabs at ambient temperature in the tropics. In addition, the possible suitability for a clear determination of likely aetiological relevance of PCR-based pathogen detections based on cycle threshold (Ct) values was assessed. From 632 Tanzanian children <5 years of age with and without gastrointestinal symptoms, 466 samples were subjected to nucleic acid extraction and real-time PCR for gastrointestinal viral, bacterial and protozoan pathogens. Equal or even higher frequencies of pathogen detections from Whatman papers or flocked swabs were achieved compared with nucleic acid extraction directly from stool samples. Comparison of the Ct values showed no significant difference according to the nucleic acid extraction strategy. Also, the Ct values did not allow a decision whether a detected pathogen was associated with gastrointestinal symptoms.

Limitations to plasticity of language network reorganization in localization related epilepsy.

Neural networks for processing language often are reorganized in patients with epilepsy. However, the extent and location of within and between hemisphere re-organization are not established. We studied 45 patients, all with a left hemisphere seizure focus (mean age 22.8, seizure onset 13.3), and 19 normal controls (mean age 24.8) with an fMRI word definition language paradigm to assess the location of language processing regions. Individual patient SPM maps were compared to the normal group in a voxel-wise comparison; a voxel was considered to be significant if its z-value exceeded mid R:2mid R:. Subsequently, we used principal component analysis with hierarchical clustering of variance patterns from individual difference maps to identify four patient sub-groups. One did not differ from normal controls; one had increased left temporal activation on the margin of regions activated in controls; two others had recruitment in right inferior frontal gyrus, middle frontal gyrus and temporal cortex. Right hemisphere activation in these two groups occurred in homologues of left hemisphere regions that sustained task activation. Our study used novel data driven methods to find evidence for constraints on inter-hemispheric reorganization of language in recruitment of right homologues, and, in a subpopulation of patients, evidence for intra-hemispheric reorganization of language limited to the margins of typical left temporal regional activation. These methods may be applied to investigate both normal and pathological variance in other developmental disorders and cognitive domains.

Lying about facial recognition: an fMRI study.

Novel deception detection techniques have been in creation for centuries. Functional magnetic resonance imaging (fMRI) is a neuroscience technology that non-invasively measures brain activity associated with behavior and cognition. A number of investigators have explored the utilization and efficiency of fMRI in deception detection. In this study, 18 subjects were instructed during an fMRI "line-up" task to either conceal (lie) or reveal (truth) the identities of individuals seen in study sets in order to determine the neural correlates of intentionally misidentifying previously known faces (lying about recognition). A repeated measures ANOVA (lie vs. truth and familiar vs. unfamiliar) and two paired t-tests (familiar vs. unfamiliar and familiar lie vs. familiar truth) revealed areas of activation associated with deception in the right MGF, red nucleus, IFG, SMG, SFG (with ACC), DLPFC, and bilateral precuneus. The areas activated in the present study may be involved in the suppression of truth, working and visuospatial memories, and imagery when providing misleading (deceptive) responses to facial identification prompts in the form of a "line-up".

Prevalence of serum antibodies to human papilloma virus in patients with genital ulcer disease in an urban population of Tanzania.

BACKGROUND: The epidemiology of human papillomavirus (HPV) in Tanzania is largely unknown both in risk groups and in the general population. OBJECTIVE: To determine the cumulative seroprevalence of selected HPV types in order to evaluate exposure to HPV in urban Tanzania. METHOD: In a cross-sectional study, sera of 200 patients of both sexes with genital ulcer disease (GUD) and sera of 60 male blood donors and 60 pregnant women were tested for antibodies to the oncogenic HPV types 16, 18, 31, 33, 35, 51 and 52 using an ELISA based on virus-like particles (VLP). RESULTS: The overall seroprevalence of HPV types for all patients with GUD was 83% and 77% for women and men, respectively. For pregnant women and male blood donors, the corresponding percentages were 55% and 15%, respectively. The most common HPV types were 16, 18 and 52. Infection with multiple types was more than 10 and 5 times more frequent than infection with a single type 16 in patients with GUD and in pregnant women, respectively. The seroprevalence to HPV types 16, 18, 51 and 52 was considerably higher in HIV-positive patients with GUD than in HIV-negative patients. CONCLUSIONS: Infections with the oncogenic HPV types 16, 18 and 52 are common among patients with GUD and pregnant women in urban Tanzania, emphasising the need for control, treatment and implementation of appropriate HPV vaccine programmes.

Molecular characterization of Haemophilus ducreyi isolates from different geographical locations.

The technique of random amplified polymorphic DNA (RAPD) was adapted and optimized to study Haemophilus ducreyi isolates. A panel of 43 strains isolated from chancroid patients from different countries in Africa, Europe, North America, and Asia were characterized. The strains were also studied with respect to lipooligosaccharide (LOS) migration and immunoblotting patterns and the presence of cytolethal distending toxin genes. The RAPD method with the OPJ20 primer generated nine banding patterns (1 to 9). The majority of the isolates were clustered into two major profiles, 14 and 13 strains into profiles 1 and 2, respectively, and just a few strains revealed patterns 3 and 4. The isolates from Thailand were exceptional in that they showed greater diversity and were represented by six different RAPD patterns, i.e., patterns 3 and 5 to 9. The LOS migration and immunoblotting analyses revealed two different patterns, which indicated long and short forms of LOS; the former was found in 20/23 tested strains. Two strains that expressed the short form of LOS were grouped into RAPD pattern 4. The absence of cdtABC genes was observed in only 4/23 strains, and three of these isolates were assigned to RAPD pattern 4. Our results showed limited genotypic and phenotypic variations among H. ducreyi strains, as supported by the conserved RAPD and LOS profiles shared by the majority of the studied strains. However, the RAPD method identified differences between strains, including those from different geographic areas, which indicate the potential of RAPD as an epidemiological tool for the typing of H. ducreyi isolates in countries where chancroid is endemic.

Sexual behaviour among youths at high risk for HIV-1 infection in Dar es Salaam, Tanzania.

OBJECTIVES: To investigate sex specific sexual behaviour in youths visiting a youth clinic for sexual and reproductive health in Dar es Saalam. METHODS: A questionnaire was administered to a random sample of youths between 10 and 24 years of age attending the youth health clinic in Dar es Saalam. The clinical investigation included testing for syphilis and HIV-1 antibodies RESULTS: 1423 youths attended the clinic between September 1997 and August 1998. The study population comprised 213 (53.5%) males and 185 (46.5%) females. 97 (24.4%) were below 20 years. The mean age at coitarche was 16.5 and 17.0 years of age for males and females, respectively. The coitarche was involuntary in 15 females (8.6%). 49.5% males reported more than five lifetime partners compared with 14.1% for females (p<0.0001). Males reported recent partners to be 2.5 years younger, while females reported them to be 5.0 years older. No contraceptive use was reported by 29.7% of the males and 40.3% of females. 52.7% females had been pregnant and 26 (14.1%) reported induced abortions. Genital discharge was found in 69.5% and 73.9% and GUD in 36.6% and 27.1% of males and females respectively. 12 males (5.9%) and 43 females (24.6%) were found to be HIV-1 infected. 13.8% of the females with only one lifetime partner were HIV-1 infected compared with 40.9% with more than five partners (p = 0.028). CONCLUSIONS: Many youths in Dar es Salaam engage in sexual behaviours that put them at risk of unwanted pregnancies and STIs including HIV infection. Female youths were more likely to contract HIV infection than males. In African urban areas youth oriented clinics can have a pivotal role in HIV/STI prevention and control

Prevalence of transfusion-associated viral infections and syphilis among blood donors in Muhimbili Medical Centre, Dar es Salaam, Tanzania.

OBJECTIVE: To determine the seroprevalence of the main transfusion-associated viral infections and syphilis among blood donors in Muhimbili Medical Centre, Dar es salaam, Tanzania. DESIGN: Cross sectional study. SETTING: The blood bank unit of Muhimbili Medical Centre in Dar es salaam, Tanzania. SUBJECTS: A consecutive sample of 300 blood donors. INVESTIGATIONS: Search for the presence of antibodies to: human immunodeficiency virus (anti-HIV), hepatitis C virus (anti-HCV), hepatitis B surface antigen (anti-HBs), human T-lymphotropic virus type 1 (anti-HTLV-1), syphilis and for hepatitis B surface antigen (HbsAg). RESULTS: The overall frequency of anti-HIV, anti-HCV, anti-HBs, HbsAg, anti-HTLV-1, and syphilis antibodies were 8.7%, 8%, 20%, 11%, 0%, and 12.7%, respectively. Among the HIV seronegative donors, the frequency of anti-HCV, anti-HBs, HBsAg, anti-HTLV-1, and syphilis antibodies were 8.8%, 22%, 11%, 0%, and 10.9%, respectively. HIV-seropositive donors had an increased risk for being positive for syphilis antibodies (OR = 3.6, 95% CI 1.4-9.0) and HBsAg (OR = 4.0, 95% CI 1.0-18.8), but not anti-HCV (OR = 0.9, 95% CI 0.86-0.97), anti-HBs (OR = 1.0, 95% CI 0.2-5.3) or anti-HTLV-1 (OR = 0.0). CONCLUSION: Donor blood including that from HIV-seronegative donors, has high frequency of HCV, HBV, and syphilis antibodies but not anti-HTLV-1. A significant association exists in the occurrence of HIV, HBV and syphilis; and due to the association of syphilis and HIV, clients with history of sexually transmitted disease should be excluded during donor selection. From these observations were recommend: (i) routine screening of donor blood for HIV, HCV, HBV, and syphilis antibodies but not HTLV-1 and; (ii) a larger study to generate more accurate estimates of the magnitude the transfusion-transmissible infectious diseases.

Susceptibility pattern of Neisseria gonorrhoeae to antimicrobial agents in Dar es Salaam.

OBJECTIVE: To determine the susceptibility pattern of local strains of Neisseria gonorrhoeae from Dar es salaam, Tanzania to locally used antibiotics. METHOD: Out of 429 Neisseria gonorrhoeae strains isolated between 1993 and 1995, one hundred and ninety nine were recovered and tested. Minimum inhibitory concentrations (MIC) of penicillin, doxycycline, erythromycin, cefuroxime and ciprofloxacin were determined by the E-test method while that of spectinomycin was measured by the agar dilution method. Penicillinase producing N. gonorrhoeae were identified by the chromogenic cephalosporin method. RESULTS: Of the 199 strains tested 128 (64%) were found to be penicillinase producing Neisseria gonorrhoeae (PPNG). Only 19 (10%) were penicillin sensitive while all penicillin resistant strains were found to be PPNG. One hundred and seventy five (88%), 11(5%) and 13 (7%) of the tested isolates were resistant, less susceptible and fully susceptible to doxycycline respectively. Resistance to cotrimoxazole, cefuroxime and ciprofloxacin was 36 (18%), 11 (6%), and 3 (2%) respectively. The trend of antibiotic susceptibility rates over the three year period of study showed a significant increase in the proportion of susceptible strains to cotrimoxazole. All of the 75 strains tested against spectinomycin were susceptible. There was a statistically significant difference between the susceptibility patterns of non-PPNG and PPNG. Non-PPNG isolates were more susceptible to doxycycline (chi 2 = 78.2, df 2, p = < 0.0001). CONCLUSION: These findings have shown that spectinomycin, ciprofloxacin and cefuroxime could continue to be used to treat gonorrhoea in our settings. Continuous surveillance of susceptibility to the commonly used antibiotics is important in order to detect emergence of resistance early and control the possible wide spread of resistant strains.

PIP: This article presents a study on the susceptibility pattern of local strains of Neisseria gonorrheae (NG) to antimicrobial agents (penicillin, doxycyline, erythromycin, cefuroxime, ciprofloxacin, cotrimoxazole, and spectinomycin) in Dar Es Salaam, Tanzania. Out of the 429 isolated strains of NG in 1993-95, 199 were included in the study. Susceptibility patterns to the six antimicrobials was determined through the E-test method, a test that measures their minimum inhibitory concentrations (MICs). On the other hand, the spectinomycin MIC was determined through the antibiotic agar dilution method. Results revealed the following patterns of susceptibility of isolates: spectinomycin (100%), ciprofloxacin (97%), Cefuroxime (89%), erythromycin (57%), cotrimoxazole (40%), doxycycline (7%), and penicillin (10%). It was also noted that NG strains are highly resistant to penicillin (64%) and doxycycline (88%). The study concludes that three drugs--spectinomycin, ciprofloxacin, and spectinomycin--could be effective in treating gonorrhea. However, a continued surveillance of common antibiotics against gonococcus is necessary for the early detection and control of strain resistance.

Cholera-like diseases due to Vibrio parahaemolyticus.

The first seven cases of cholera-like disease due to Vibrio parahaemolyticus, acquired mainly through handling of raw fish from the Indian Ocean, in Dar es Salaam are reported. Five of the patients were young women, two of those being fishmongers. The duration of the disease in six of the patients was short leading to recovery within 24 h. One of the patients took 4 days of intensive rehydration therapy before recovery. Whereas V. parahaemolyticus is the commonest cause of food poisoning in Japan where raw or half cooked salt water fish are a common delicacy, the disease in Tanzania where raw fish is almost never eaten, appears to have resulted mainly from poor personal hygiene in handling raw fish. It is recommended that more studies on the problem should be carried out and the public should be educated on the dangers of unhygienic handling of raw fish.