A global non-invasive methodology for the phenotyping of potato under water deficit conditions using imaging, physiological and molecular tools

BACKGROUND

Drought is a major consequence of global heating that has negative impacts on agriculture. Potato is a drought-sensitive crop; tuber growth and dry matter content may both be impacted. Moreover, water deficit can induce physiological disorders such as glassy tubers and internal rust spots. The response of potato plants to drought is complex and can be affected by cultivar type, climatic and soil conditions, and the point at which water stress occurs during growth. The characterization of adaptive responses in plants presents a major phenotyping challenge. There is therefore a demand for the development of non-invasive analytical techniques to improve phenotyping.

RESULTS

This project aimed to take advantage of innovative approaches in MRI, phenotyping and molecular biology to evaluate the effects of water stress on potato plants during growth. Plants were cultivated in pots under different water conditions. A control group of plants were cultivated under optimal water uptake conditions. Other groups were cultivated under mild and severe water deficiency conditions (40 and 20% of field capacity, respectively) applied at different tuber growth phases (initiation, filling). Water stress was evaluated by monitoring soil water potential. Two fully-equipped imaging cabinets were set up to characterize plant morphology using high definition color cameras (top and side views) and to measure plant stress using RGB cameras. The response of potato plants to water stress depended on the intensity and duration of the stress. Three-dimensional morphological images of the underground organs of potato plants in pots were recorded using a 1.5 T MRI scanner. A significant difference in growth kinetics was observed at the early growth stages between the control and stressed plants. Quantitative PCR analysis was carried out at molecular level on the expression patterns of selected drought-responsive genes. Variations in stress levels were seen to modulate ABA and drought-responsive ABA-dependent and ABA-independent genes.

CONCLUSIONS

This methodology, when applied to the phenotyping of potato under water deficit conditions, provides a quantitative analysis of leaves and tubers properties at microstructural and molecular levels. The approaches thus developed could therefore be effective in the multi-scale characterization of plant response to water stress, from organ development to gene expression.

The burden of hepatitis C virus in Cameroon: Spatial epidemiology and historical perspective

Cameroon is thought to have one of the highest prevalences of hepatitis C virus (HCV) infection in the world (4.9% among adults). A marked cohort effect exists in several communities where ≈50% of the elderly are infected. Better assessment of HCV distribution is needed for planning treatment programmes. We tested for HCV antibodies 14 150 capillary blood samples collected during the 2011 Demographic and Health Survey, whose participants were representative of the Cameroonian population aged 15-49 (both genders) and 50-59 years (men only). Historical data on exposure to medical care were collected and factors associated with HCV assessed through logistic regression and geospatial analyses. To estimate prevalence in all persons aged ≥15 years, we used data from the survey for the 15-59 years fraction and modelled a cohort effect for older individuals. The nationwide HCV prevalence was 0.81% for the 15-49 years group, and 2.51% for all individuals aged ≥15 years. Only 0.2% of individuals aged 15-19 were seropositive. Among participants aged 15-44 years, HCV was associated with age, rural residence and, for males, with ritual circumcision. For those aged 45-59 years, HCV was associated with age and access to medical care in the late 1950s. Prevalence of HCV seropositivity in Cameroon is half of previous estimates. Nationwide surveys are essential to rationalize resources allocation. The high prevalence among older cohorts, a colonial legacy, has had little spillover into younger cohorts. HCV-free generations might be attainable in countries not plagued with intravenous drug abuse.

Fatal Clostridium difficile enteritis caused by the BI/NAP1/027 strain: a case series of ileal C. difficile infections

Clostridium difficile generally causes diarrhoea and colitis. Small-bowel infections are considered to be rare. Twelve cases of ileal C. difficile infections are presented, including the first reported case proven to be caused by the hypervirulent BI/NAP1/027 strain. This case series suggests that small bowel involvement in C. difficile infections may be more frequent than previously thought.

Satisfaction with health services for STIs, HIV, AIDS among a high-risk population in West Africa

The goal of this study was to develop an instrument and assess the degree of satisfaction regarding HIV/STIs services for women working in, associated with, or living in or nearby, prostitution environments. This study took place in seven West-African countries (Benin, Burkina Faso, Ghana, Mali, Niger, Senegal, Togo) participating in the West Africa Aids Program (AIDS3). A validated six-dimension questionnaire was used to interview 698 women. The main inclusion criterion was having had recourse to adapted services offered through the AIDS3 program in the last six months. Results showed that women surveyed are satisfied overall. Two dimensions scored low: 'Technical skills perceived' and 'Accessibility'. Regression analyses showed that those most satisfied were women who had used the adapted services many times and women connected with community groups. Although these results are consistent with results published previously in other contexts, they now allow the AIDS3 program to consider the voices of women rarely listened to: West-African women living and working in prostitution environments.

Mycoplasma genitalium: an organism commonly associated with cervicitis among west African sex workers

OBJECTIVES

To identify the contribution of Mycoplasma genitalium to the aetiology of cervicitis in sub-Saharan Africa and its relative importance in the overall burden of sexually transmitted infections among female sex workers (FSW).

METHODS

The study population consisted of FSW recruited in Ghana and Benin during the initial visit of a randomised controlled trial. A questionnaire was administered, a pelvic examination carried out, and cervical samples obtained for detection of M genitalium, Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis. Clinical signs potentially indicating cervicitis were cervical discharge, pus on the cervical swab, bleeding after sampling, and inflammatory cervix.

RESULTS

Among 826 FSW, 26.3% were infected with M genitalium. N gonorrhoeae was strongly and independently associated with each of the four signs of cervicitis (adjusted odds ratios (AOR): 4.1 to 6.0). The AOR for C trachomatis were intermediate (1.3-4.1) and the AOR for M genitalium were lower (between 1.6 and 1.8) but statistically significant (p< or =0.05) for each sign.

CONCLUSIONS

M genitalium is weakly associated with signs of cervicitis in west African FSW but is highly prevalent.

Low prevalence of cervical infections in women with vaginal discharge in west Africa: implications for syndromic management

OBJECTIVES

To measure prevalence and risk factors for cervical infections among a large sample of women consulting for vaginal discharge in west Africa and to evaluate its syndromic management through a two visit algorithm.

METHODS

In 11 health centres in Bénin, Burkina Faso, Ghana, Guinée, and Mali 726 women who presented with a vaginal discharge without abdominal pain and who denied being a sex worker (SW) were enrolled. Cervical samples were tested for the detection of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) with polymerase chain reaction (PCR) assays. All participants were treated with single dose (2 g) metronidazole and clotrimazole cream for 3 days. They were randomised to be told either to come back on day 7 only if there was no improvement in the discharge (group A), or to come back on day 7 regardless of response to treatment (group B).

RESULTS

Overall, the prevalence of NG and CT was only 1.9% (14/726) and 3.2% (23/726) respectively. Risk factors previously recommended by the WHO were not associated with the presence of cervical infection, with the exception of the number of sex partners in the past 3 months. When taken together, these risk factors had a positive predictive value of only 6.4% to identify cervical infections. Prevalence of cervical infection was not higher in women who came back on day 7, regardless of the strategy used. Prevalence of NG/CT was lower in Ghana and Bénin (5/280, 1.8%), where comprehensive interventions for SW have been ongoing for years, than in the three other countries (27/446, 6.1%, p = 0.01).

CONCLUSIONS

NG and CT infections are uncommon in west African women who consult for vaginal discharge and who are not SW. Syndromic management of vaginal discharge should focus on the proper management of vaginitis. The control of gonococcal and chlamydial infection should be redesigned around interventions focusing on sex workers.

Mycoplasma genitalium is not associated with adverse outcomes of pregnancy in Guinea-Bissau

OBJECTIVE

To evaluate the impact of Mycoplasma genitalium on the outcome of pregnancy.

METHODS

Cervical samples from women who had previously participated in a case-control study (designed to assess the impact of syphilis and HIV-2 on the outcome of pregnancy in Guinea-Bissau) were processed using a PCR assay to detect the presence of M genitalium. Controls were women who had delivered a term neonate with a birth weight over 2500 g. Cases were classified into four groups of mothers according to the outcome of pregnancy: stillbirths, spontaneous abortions, premature deliveries, and small for gestational age (SGA) babies.

RESULTS

Among the 1014 women included in this study, 6.2% were infected with M genitalium. M genitalium infection was not significantly associated with any of the adverse outcomes of pregnancy studied. Odds ratios (OR) for premature or SGA delivery in the presence of M genitalium infection were 1.37 (95% CI 0.69 to 2.60) and 0.44 (95% CI 0.01 to 2.75), respectively. For abortions and stillbirths, OR were respectively 0.61 (95% CI 0.07 to 2.51) and 1.07 (95% CI 0.42 to 2.42).

CONCLUSION

M genitalium appears not to have a deleterious impact on the outcome of pregnancy.

The epidemiology and control of human African trypanosomiasis

Human African trypanosomiasis is caused by Trypanosoma brucei gambiense in West and Central Africa, and by Trypanosoma brucei rhodesiense in East and southern Africa. In recent years there has been a dramatic resurgence of Gambian trypanosomiasis in Central Africa, especially in the Democratic Republic of Congo, Angola and Sudan. The disease is quiescent in most of West Africa, as is Rhodesian trypanosomiasis the other side of the continent. The epidemiology of Gambian trypanosomiasis is reviewed in detail. The long duration of infection in human hosts with cycles of intermittent parasitaemia, the vectors' feeding habits and the intensity of human-fly contact are the major determinants of the dynamics of transmission of this parasite. The development of immunity may lead to a reduction in the fraction of the population that is susceptible to infection and the burning out of epidemics after 20 to 30 years. So far, the acquired immune deficiency syndrome pandemic has had no impact on the epidemiology of Gambian trypanosomiasis. A brief review of the epidemiology of Rhodesian trypanosomiasis highlights the differences from Gambian trypanosomiasis that, to some extent, explain its lower propensity to cause epidemics: it is a more aggressive disease that rapidly kills its human host, and its transmission involves mostly domestic and game animals, humans being in most circumstances an accidental host. The various methods and strategies for the surveillance and control of both diseases are reviewed.

HIV infection among sex workers in Accra: need to target new recruits entering the trade

OBJECTIVE

Description of the epidemiology of HIV infection among sex workers (SW) in Accra, Ghana.

METHODS

In all, 1013 SW working out of their homes ( seaters ) or finding customers in bars, hotels, brothels or on the street ( roamers ) were interviewed and tested for HIV.

RESULTS

Overall, prevalence of HIV infection was nearly 50% (506 of 1013), varying from 26% (133 of 507) among the roamers to 74% (368 of 496) among the seaters. Profound differences were noted between these two categories of SW with regard to age, number of clients per day, price per instance of intercourse, condom use, and other characteristics. Respectively, 27% and 58% of roamers and seaters were infected with HIV within their first 6 months of sex work, despite a limited number of unprotected sex acts with seropositive clients. Independent risk factors for HIV infection varied between types of SW: age among the roamers; region of origin and duration of sex work among the seaters; number of clients per day, and presence of current or past genital ulcer and gonococcal cervicitis in both groups.

CONCLUSION

In Accra, considerable heterogeneity exists in the population of SWs. In both categories of SW, new recruits become rapidly infected with HIV after entering the trade. The 25-fold higher prevalence of HIV among SWs than in the general adult population suggests that in Accra, as in many cities of West Africa, a high fraction of new cases of HIV infection continue to be acquired from SWs. Intervention programs targeting SW should be an essential component of national AIDS control strategies. Special efforts should be made to identify and offer preventive services to new sex workers.

Pharmacists' role in managing sexually transmitted infections: policy issues and options for Ghana

The debate about extending the role of pharmacists in health care is growing in recognition of the ongoing difficulties experienced by many public sector services. The perceived accessibility and confidentiality of pharmacists makes them particularly attractive to patients for the management of health problems such as sexually transmitted infections (STI) that may lead to stigmatization. Despite growing interest in the subject, there are few documented analyses of the role of pharmacists in low-income countries. In Ghana, pharmacists are acknowledged by the government to be the preferred option for people seeking treatment for STI. A study was conducted to investigate the current role played by pharmacists in Greater Accra Region in the management of STI. On the basis of these findings, training schemes were developed, implemented and evaluated. This paper presents the findings of this operation-research and considers their implications for deciding to what extent and in what way pharmacists should be involved in managing STI in Ghana and other similar country settings. These findings suggest that pharmacists have a crucial role in effective management of STI, particularly in the management of urethral discharge. They may need to limit their management of genital ulcer to referring customers to laboratories and medical practitioners. They also represent a currently under-utilized opportunity for preventive activities. Regulation and quality assurance issues need to be addressed by both pharmacy and medical professions.

Acute lower respiratory infections among children hospitalized in Bangui, Central African Republic: toward a new case-management algorithm

To measure the performance of the current WHO algorithm in identifying children at higher risk of death, children aged 2-59 months who presented with cough and/or difficult breathing and were admitted into the paediatric hospital of Bangui (Central African Republic) during a 1-year period (1996/97) were investigated. Among children with subcostal indrawing, mortality and severity of oxygen desaturation were identical whether or not they also had tachypnoea. Among children with a 'severe pneumonia', those who also fulfilled the 'very severe disease' definition had a higher risk of death (31/132, 23.5%) than those who did not (12/106, 11.3%, P = 0.02). However, this 'very severe disease' definition did not predict death when used in children who did not have severe pneumonia. To identify variables that would better predict death, combinations of symptoms and signs were examined among the subgroup of children with indrawing. Nine combinations had both a sensitivity and specificity over 60%. 'Grunting and/or nasal flaring' had a sensitivity of 72% and a specificity of 66% in predicting death, and might be easier to use by primary health care personnel than other combinations. A new algorithm is proposed for the management of children aged 2-59 months presenting with cough and/or difficult breathing. The definition of pneumonia would be unchanged (tachypnoea). Severe pneumonia would remain defined on indrawing regardless of respiratory rate, except that indrawing should be lower chest wall and/or intercostal. In health facilities where intravenous antibiotics, chloramphenicol and/or oxygen are available, entry into a 'very severe pneumonia' category would be based on 'grunting and/or nasal flaring' among children with indrawing. In our study population, the mortality rates in the categories based on these definitions were 0.8% (1/127) in children with no pneumonia, 0.9% (1/116) in children with pneumonia, 7.7% (12/156) in children with severe pneumonia and 31.1% (33/106) in children with very severe pneumonia.

Aetiology of urethral discharge in Bangui, Central African Republic

OBJECTIVES

To determine the aetiology of urethritis in Bangui, Central African Republic.

METHODS

410 men presenting with urethral discharge and 100 asymptomatic controls were enrolled. Urethral swabs were obtained and processed by gonococcal culture and polymerase chain reaction for the detection of Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Trichomonas vaginalis, and Ureaplasma urealyticum.

RESULTS

In multivariate analyses, M genitalium and C trachomatis were significantly associated with urethral discharge when comparing cases of non-gonococcal urethritis (NGU) with controls. T vaginalis was also more common in cases than in controls, but this reached statistical significance only among cases in whom N gonorrhoeae was also detected. U urealyticum was not associated with urethritis. The gonococcus was found in 69% of cases of urethral discharge. M genitalium was the predominant pathogen in patients with NGU, being found in 42% (53/127) of such patients while C trachomatis was found in only 17% (22/127). T vaginalis was found in 18% (23/127) of patients with NGU, but also in 15% (43/283) of patients with gonococcal urethritis, and two thirds of patients with T vaginalis also had the gonococcus. Multiple infections were common. M genitalium caused a syndrome similar to chlamydial urethritis, with a less severe inflammation than in gonococcal infection. No behavioural or clinical characteristic could discriminate between the various aetiological agents.

CONCLUSIONS

M genitalium is more prevalent than C trachomatis and is the most common cause of NGU in BANGUI: It causes a syndrome similar to chlamydial urethritis. T vaginalis is weakly associated with urethritis, and is often found along with other pathogens.

Etiology of urethral discharge in West Africa: the role of Mycoplasma genitalium and Trichomonas vaginalis

OBJECTIVE

To determine the etiological role of pathogens other than Neisseria gonorrhoeae and Chlamydia trachomatis in urethral discharge in West African men.

METHODS

Urethral swabs were obtained from 659 male patients presenting with urethral discharge in 72 primary health care facilities in seven West African countries, and in 339 controls presenting for complaints unrelated to the genitourinary tract. Polymerase chain reaction analysis was used to detect the presence of N. gonorrhoeae, C. trachomatis, Trichomonas vaginalis, Mycoplasma genitalium, and Ureaplasma urealyticum.

FINDINGS

N. gonorrhoeae, T. vaginalis, C. trachomatis, and M. genitalium--but not U. urealyticum--were found more frequently in men with urethral discharge than in asymptomatic controls, being present in 61.9%, 13.8%, 13.4% and 10.0%, respectively, of cases of urethral discharge. Multiple infections were common. Among patients with gonococcal infection, T. vaginalis was as frequent a coinfection as C. trachomatis. M. genitalium, T. vaginalis, and C. trachomatis caused a similar clinical syndrome to that associated with gonococcal infection, but with a less severe urethral discharge.

CONCLUSIONS

M. genitalium and T. vaginalis are important etiological agents of urethral discharge in West Africa. The frequent occurrence of multiple infections with any combination of four pathogens strongly supports the syndromic approach. The optimal use of metronidazole in flowcharts for the syndromic management of urethral discharge needs to be explored in therapeutic trials.

Quality of sexually transmitted disease treatments in the formal and informal sectors of Bangui, Central African Republic

BACKGROUND

Interventions for upgrading sexually transmitted disease (STD) management in sub-Saharan Africa have focused on the public sector, and to a much lower extent on private medical practitioners and pharmacies. However, in most African cities there is a large informal sector that provides care to many patients with STD symptoms.

GOAL

To compare the quality of treatments offered to patients with major STD syndromes in the public sector, pharmacies, and the informal sector of the same city.

STUDY DESIGN

Healthcare providers in health centers, pharmacies, private laboratories, and market drug peddlers in Bangui, Central African Republic, were asked to complete a short form for every patient consulting them with genital complaints. The treatments they ordered were evaluated for their potential efficacy against the major etiologic agents of the syndrome for which the patient consulted.

RESULTS

The majority of male patients with STDs preferred to seek care in pharmacies and in the informal sector. The STD treatments offered to patients with urethral discharge or genital ulcers in pharmacies and in the informal sector tended to focus on a single etiologic agent. The quality of STD treatments offered by drug peddlers and private laboratories was poor, apart from adequate coverage of syphilis in patients with genital ulcers and of candidiasis in women with vaginal discharge. For instance, 41% and 34% of patients with urethral discharge managed by drug peddlers and private laboratories did not receive a drug active against either Neisseria gonorrhoeae or Chlamydia trachomatis, whereas this proportion was 22% in pharmacies and 14% in health centers. For patients with genital ulcers, the proportion offered a drug active against Haemophilus ducreyi was 2% if seen by drug peddlers, 0% in laboratories, 10% in pharmacies, and 25% in health centers. For each syndrome and each category of provider, between one fourth and two thirds of patients had already received another ineffective treatment elsewhere.

CONCLUSION

National STD and HIV control programs will have to improve STD management in pharmacies and in the informal sector if they are to have any impact on the dynamics of HIV infection in urban centers.

Low levels of high density lipoproteins in Turks, a population with elevated hepatic lipase. High density lipoprotein characterization and gender-specific effects of apolipoprotein e genotype

Turks have strikingly low levels of high density lipoprotein cholesterol (HDL-C) (10-15 mg/dL lower than those of Americans or Western Europeans) associated with elevated hepatic lipase mass and activity. Here we report that Turks have low levels of high density lipoprotein subclass 2 (HDL(2)), apoA-I-containing lipoproteins (LpA-I), and pre-beta-1 HDL and increased levels of HDL(3) and LpA-I/A-II particles (potentially an atherogenic lipid profile). The frequency distributions of HDL-C and LpA-I levels were skewed toward bimodality in Turkish women but were unimodal in Turkish men. The apoE genotype affected HDL-C and LpA-I levels in women only. In women, but not men, the varepsilon2 allele was strikingly more prevalent in those with the highest levels of HDL-C and LpA-I than in those with the lowest levels. The higher prevalence of the epsilon2 allele in these subgroups of women was not explained by plasma triglyceride levels, total cholesterol levels, age, or body mass index. The modulating effects of apoE isoforms on lipolytic hydrolysis of HDL by hepatic lipase (apoE2 preventing efficient hydrolysis) or on lipoprotein receptor binding (apoE2 interacting poorly with the low density lipoprotein receptors) may account for differences in HDL-C levels in Turkish women (the epsilon2 allele being associated with higher HDL levels). In Turkish men, who have substantially higher levels of hepatic lipase activity than women, the modulating effect of apoE may be overwhelmed. The gender-specific impact of the apoE genotype on HDL-C and LpA-I levels in association with elevated levels of hepatic lipase provides new insights into the metabolism of HDL.

Improvement of clinical algorithms for the diagnosis of Neisseria gonorrhoeae and Chlamydia trachomatis by the use of Gram-stained smears among female sex workers in Accra, Ghana

BACKGROUND

Screening for cervical infection is difficult in developing countries. Screening strategies must be improved for high-risk women, such as female sex workers.

GOAL

To evaluate the sensitivity and specificity of screening algorithms for cervical infection pathogens among female sex workers in Accra, Ghana.

STUDY DESIGN

A cross-sectional study among female sex workers was conducted. Each woman underwent an interview and a clinical examination. Biologic samples were obtained for the diagnosis of HIV, syphilis, bacterial vaginosis, yeast infection, Trichomonas vaginalis, Neisseria gonorrhoeae, and Chlamydia trachomatis infection. Signs and symptoms associated with cervicitis agents were identified. Algorithms for the diagnosis of cervical infection were tested by computer simulations.

RESULTS

The following prevalences were observed: HIV, 76.6%; N. gonorrhoeae, 33.7%; C. trachomatis, 10.1%; candidiasis, 24.4%; T. vaginalis, 31.4%; bacterial vaginosis, 2.3%; serologic syphilis, 4.6%; and genital ulcers on clinical examination, 10.6%. The best performance of algorithms were reached when using a combination of clinical signs and a search for gram-negative diplococci on cervical smears (sensitivity, 64.4%; specificity, 80.0%).

CONCLUSIONS

In the algorithms, examination of Gram-stained genital smears in female sex workers without clinical signs of cervicitis improved sensitivity without altering specificity for the diagnosis of cervical infection.

Risk factors for mortality among children hospitalized because of acute respiratory infections in Bangui, Central African Republic

BACKGROUND

Acute respiratory infections are the most common cause of death in children in developing countries. Little information is available on risk factors for mortality among African children presenting with symptoms compatible with acute respiratory infections.

OBJECTIVE

To identify risk factors for death among children hospitalized for respiratory complaints who satisfy the WHO clinical definition for pneumonia or severe pneumonia.

METHODS

Children <5 years of age who presented with cough and/or difficult breathing and were hospitalized in Bangui during a 1-year period were investigated for risk factors for mortality. The study population consisted of 395 children who satisfied the WHO clinical definition for pneumonia/severe pneumonia. The associations between death and demographic, nutritional, socioeconomic, laboratory and clinical variables were examined.

RESULTS

Of the 49 (12.4%) children who died, all but one had had indrawing of the chest which, in univariate analysis, was the risk factor most strongly associated with death [odds ratio, 22.99; 95% confidence interval (CI), 3.81 to 935.2]. In a multivariate model the independent risk factors for death were indrawing of the chest [adjusted odds ratio (AOR) 8.35, CI 1.04 to 66.82], hepatomegaly (AOR 6.72, CI 2.35 to 19.21), age between 2 and 11 months (AOR 6.37, CI 2.18 to 18.59), grunting (AOR 4.53, CI 1.96 to 10.45), a moderate/severe alteration of general status (AOR 3.23, CI 1.17 to 8.94) and acute malnutrition (AOR 2.74, CI 0.96 to 7.78).

CONCLUSIONS

These findings could be used in flow charts for the management of children with respiratory complaints to identify children at increased risk of death who need to receive aggressive therapy.

Short-course eflornithine in Gambian trypanosomiasis: a multicentre randomized controlled trial

OBJECTIVE

A randomized controlled trial was conducted to determine whether 7 days of intravenous eflornithine (100 mg/kg every 6 h) was as effective as the standard 14-day regimen in the treatment of late-stage Trypanosoma brucei gambiense trypanosomiasis.

METHODS

A total of 321 patients (274 new cases, 47 relapsing cases) were randomized at four participating centres in Congo, Côte d'Ivoire, the Democratic Republic of the Congo, and Uganda to one of these treatment regimens and followed up for 2 years.

RESULTS

Six patients died during treatment, one of whom was on the 7-day regimen, whereas the other five had been on the 14-day regimen (P = 0.2). The response to eflornithine differed markedly between Uganda and other countries. Among new cases in Uganda, the 2-year probability of cure was 73% on the 14-day course compared with 62% on the 7-day regimen (hazard ratio (HR) for treatment failure, 7-day versus 14-day regimen: 1.45, 95% CI: 0.7, 3.1, P = 0.3). Among new cases in Côte d'Ivoire, Congo, and the Democratic Republic of the Congo combined, the 2-year probability of cure was 97% on the 14-day course compared with 86.5% on the 7-day regimen (HR for treatment failure, 7-day vs 14-day: 6.72, 95% confidence interval (CI): 1.5, 31.0, P = 0.003). Among relapsing cases in all four countries, the 2-year probability of cure was 94% with 7 days and 100% with 14 days of treatment. Factors associated with a higher risk of treatment failure were: a positive lymph node aspirate (HR 4.1; 95% CI: 1.8-9.4), a cerebrospinal fluid (CSF) white cell count > or = 100/mm3 (HR 3.5; 95% CI: 1.1-10.9), being treated in Uganda (HR 2.9; 95% CI: 1.4-5.9), and CSF trypanosomes (HR 1.9; 95% CI: 0.9-4.1). Being stuporous on admission was associated with a lower risk of treatment failure (HR 0.18; 95% CI: 0.02-1.4) as was increasing age (HR 0.977; 95% CI: 0.95-1.0, for each additional year of age).

DISCUSSION

The 7-day course of eflornithine is an effective treatment of relapsing cases of Gambian trypanosomiasis. For new cases, a 7-day course is inferior to the standard 14-day regimen and cannot be recommended.

Familial aggregation of Trypanosoma brucei gambiense trypanosomiasis in a very high incidence community in Zaire

Familial aggregation of Trypanosoma brucei gambiense human African trypanosomiasis (HAT) was investigated in 3 adjacent villages of central Zaire where 318/1431 inhabitants had previously suffered from HAT. Neither spatial nor familial aggregation was detected when analysing the distribution of cases in the whole community using Poisson, negative binomial and pairwise odds ratio models. However, clustering of cases was observed when specific familial relationships were examined. The risk of HAT for a child was significantly increased if the mother had also had HAT, but it was not influenced by a past history of HAT in the father. Sisters and brothers of cases of HAT had a higher risk of HAT than siblings of individuals who had never had HAT, but no such association was documented for half-sisters and half-brothers. Among married couples, a past history of HAT in one spouse had no impact on the other spouse's risk of HAT. Indirect arguments suggested that familial clustering was a consequence of shared exposure, either sequential or simultaneous, rather than of genetic susceptibility. The existence of familial clustering should be kept in mind when implementing passive or active case-finding activities.

A seven days course of eflornithine for relapsing Trypanosoma brucei gambiense sleeping sickness

Forty-seven patients with a relapse following a first treatment of Trypanosoma brucei gambiense trypanosomiasis were treated with a 7 d course of intravenous eflornithine (100 mg/kg every 6 h) and followed for 2 years. Four patients died after treatment, 2 of them possibly due to trypanosomiasis. One patient was completely lost to follow-up, 36 were followed for at least one year, and 25 have completed the 2 years' follow-up. Only one patient, a 5 years old child, subsequently relapsed. Considering this child and 2 of the fatalities as treatment failures, the rate of failure was 6.5%. A 7 d course of intravenous eflornithine is an adequate treatment for cases of Gambian trypanosomiasis relapsing after treatment with another drug.

Relapses following treatment of early-stage Trypanosoma brucei gambiense sleeping sickness with a combination of pentamidine and suramin

616 patients with early Trypanosoma brucei gambiense trypanosomiasis (no trypanosomes in the cerebrospinal fluid [CSF] and a CSF white cell count [WCC] of 1-5/mm3) were treated with a combination of pentamidine (6 intramuscular [i.m.] injections of 4 mg/kg) and suramin (2 intravenous [i.v.] injections of 20 mg/kg) in Nioki hospital, Zaire, between 1983 and 1992; 46 (7.5%) of them subsequently relapsed. There was no increase in the frequency of treatment failure during this 10 years' period. Relapses were more frequent in children aged 0-17 years (19/163 [11.7%]) than in adults (26/420 [6.2%] (relative risk [RR] = 1.88, 95% confidence interval [CI] 1.07-3.31, P = 0.04). Even within this small range of CSF WCC, the risk of treatment failure increased in parallel with the WCC count and reached 10/36 (27.8%) in patients with a CSF WCC of 5/mm3. Treatment failures were more frequent (5/30 [16.7%]) in a small group of patients treated with a combination of diminazene (3 i.m. injections of 7 mg/kg) and suramin (one i.v. injection of 20 mg/kg) than in the pentamidine/suramin group (RR = 2.23, 95% CI 0.96-5.21, P = 0.08). Our data support the view that central nervous system involvement occurs early in Gambian trypanosomiasis, which in turn raises doubts about the usefulness of adding suramin to pentamidine, as the former drug, which is more expensive than pentamidine and has to be administered intravenously, penetrates poorly into the CSF and may potentially decrease free pentamidine levels in blood and CSF.

Epidemiological evidence for immunity following Trypanosoma brucei gambiense sleeping sickness

In order to investigate whether protective immunity appears after Trypanosoma brucei gambiense sleeping sickness, we undertook a retrospective cohort study of 3 remote villages in central Zaire (total population 1431), in which 38% of all adults had a past history of human African trypanosomiasis. Among adults previously diagnosed with trypanosomiasis and treated, the risk of a second episode of trypanosomiasis during the 10 years period of observation was only 15% (with a 24 months refractory period) and 30% (without a refractory period) of the risk of a first episode in adults never previously diagnosed. We could not demonstrate a similar difference among children, to some extent because only a few of them were diagnosed for a first time with trypanosomiasis. Our findings suggest that very significant immunity appears after Gambian sleeping sickness, and that developing a vaccine against this subspecies of trypanosomes is biologically plausible.

Risk factors for encephalopathy and mortality during melarsoprol treatment of Trypanosoma brucei gambiense sleeping sickness

This paper reviews the incidence of, and risk factors for, drug-induced encephalopathy and mortality (from all causes) during treatment with melarsoprol of 1083 patients with Trypanosoma brucei gambiense sleeping sickness in Nioki hospital (Zaire) between 1983 and 1990. Sixty-four patients (5.9%) developed encephalopathy and 62 (5.7%) died: 43 from reactive encephalopathy and 19 from other causes. Univariate and multivariate analyses showed that the administration of prednisolone reduced significantly the incidence of encephalopathy and mortality during treatment, especially in patients with trypanosomes observed in the cerebrospinal fluid (CSF) and/or with a CSF white blood cell (WBC) count of 100 or more per mm3. The risk of encephalopathy was associated more strongly with the CSF WBC count than with the presence of CSF trypanosomes. In the subgroup of patients with a CSF WBC count of 100 or more mm3, changing the melarsoprol regimen to 3 series of 3 injections instead of 3 series of 4 injections halved the mortality rate during treatment. Treatment of patients who do develop reactive encephalopathy with the heavy metal chelator dimercaprol, in addition to intravenous steroids and anticonvulsants, may be harmful. The data suggest that a further reduction of the total dose of melarsoprol may decrease toxicity without jeopardizing efficacy.

[Control of Trypanosoma gambiense trypanosomiasis. Evaluation of a strategy based on the treatment of serologically suspected cases with a single dose of diminazene]

A novel method for the control of T.b. gambiense trypanosomiasis was evaluated in an endemic focus of Zaïre where a high incidence had persisted despite massive participation in active case-finding surveys based on lymph node puncture. All inhabitants of 3 villages were examined with a card agglutination serological test (CATT), and parasitological examinations were performed on those who were CATT+. Individuals in whom we detected trypanosomes were treated as usual. A lumbar puncture was carried out on CATT+/parasitology- subjects; those whose cerebrospinal fluid showed more than 3 white blood cell (WBC) per mm3 were treated with a full course of melarsoprol while those with a CSF WBC count between 1 and 3 per mm3 were given a single injection of diminazene (7 mg/kg). Three such surveys were performed, with a 6-month interval, during which 282 "serological suspects" received diminazene, 39 "clinical cases" were given melarsoprol and 82 "parasitological cases" were treated according to standard protocols. The annual incidence of trypanosomiasis decreased rapidly from 10.4-41.1/1.000 inhabitants (mean: 17.6/1.000) during the 10 years before the intervention to 1.1-2.6/1.000 (mean: 1.7/1.000) in the 3 years following the intervention. No major adverse effect was seen with diminazene. Among the 282 serological suspects, an elevated CSF WBC count was later documented in 12 individuals, who were all cured with melarsoprol. The incidence increased 5 years after the intervention (7.1/1.000 in 1992), which may have been avoided had we carried out similar interventions in adjacent foci.

Gambiense trypanosomiasis: frequency of, and risk factors for, failure of melarsoprol therapy

1083 patients with late-stage Trypanosoma brucei gambiense sleeping sickness were treated with melarsoprol in Nioki hospital, Zaire, between 1983 and 1990. Sixty-two (5.7%) died during treatment. Of the 1021 patients who survived the treatment, 63 (6.2%) subsequently relapsed, 58 (92%) of whom were diagnosed within 2 years of melarsoprol treatment. There was no evidence of an increase in the frequency of treatment failures during the study period, and the rate of relapses that we documented is comparable to that reported from Zaire more than 30 years ago. Relapses were more frequent among patients who had trypanosomes seen in the cerebrospinal fluid (CSF) at the time of the initial diagnosis (odds ratio [OR] = 2.76, 95% confidence interval [CI] = 1.65-4.63, P = 0.0001). Male patients had twice as many relapses as females (OR = 2.00, 95% CI = 1.19-3.36, P = 0.009), which was partly explained by males having trypanosomes in the CSF more often than females. There were important geographical variations in the frequency of relapses within the territory of the Nioki rural health zone, suggesting that the circulation of trypanosomes was geographically limited. Prednisolone treatment did not increase the risk of treatment failure, nor did decreasing the total dose of melarsoprol from 12 to 9 injections for patients with > or = 100 white blood cells/mm3 of CSF. Since patients with trypanosomes in the CSF are also those who are at the highest risk of melarsoprol-induced encephalopathy, more aggressive treatment regimens cannot be recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

Eflornithine concentrations in serum and cerebrospinal fluid of 63 patients treated for Trypanosoma brucei gambiense sleeping sickness

Eflornithine (difluoromethylornithine, DFMO) has recently been approved for the treatment of Trypanosoma brucei gambiense trypanosomiasis. Treatment failures have been infrequent but have occurred among patients treated with oral DFMO only, and among children. To investigate the higher frequency of failures observed in young patients, DFMO trough concentrations in serum and cerebrospinal fluid (CSF) were measured at the end of treatment in 13 children and 50 adults who had received 200 mg/kg intravenously every 12 h for 14 d. Mean DFMO concentration in CSF was significantly lower among children aged less than 12 years when compared to older patients (25.1 vs 68.9 nmol/mL, P < 0.001). Mean serum concentration was also lower in children (49.2 vs 87.5 nmol/mL, P = 0.03). Among patients who received DFMO as initial therapy for sleeping sickness, the mean CSF/serum ratio was lower in children (0.41 vs 0.91, P < 0.005). The 3 patients who failed DFMO treatment had CSF trough concentrations around or below 50 nmol/mL. Convulsions and anaemia were associated with higher drug levels and previous therapy with melarsoprol. The lower CSF drug concentrations observed in children could result from higher renal clearance and different CSF pharmacokinetics of DFMO in that age group. To avoid treatment failures, a 6-hourly regimen as well as higher DFMO dosage based on body surface area rather than on weight are recommended for children.

The effects of post-test counselling on condom use among prostitutes in The Gambia

OBJECTIVES

To determine the effect of counselling on condom use by prostitutes.

DESIGN

Cohort study.

SETTING

Field-based study in The Gambia.

PARTICIPANTS

Thirty-one (12 HIV-positive and 19 HIV-negative) prostitutes.

INTERVENTIONS

Post-test HIV counselling.

MAIN OUTCOME MEASURES

Levels of condom use.

RESULTS

Overall, counselling had no effect on condom use.

CONCLUSIONS

Scarce resources should be directed towards providing condoms in bars rather than counselling.

Efficacy and toxicity of eflornithine for treatment of Trypanosoma brucei gambiense sleeping sickness

The usual first-line treatment for Trypanosoma brucei gambiense sleeping sickness is melarsoprol, but when that fails the outlook has hitherto been grim. The polyamine synthesis inhibitor eflornithine (difluoromethylornithine, DFMO) has emerged as an alternative therapy. 207 patients with late-stage T b gambiense sleeping sickness were treated in rural Zaire with three different regimens of DFMO in an open-trial design. During treatment, trypanosomes disappeared from the CSF of all 87 patients in whom parasites had been seen before DFMO administration, and there was a sharp fall in CSF white cell count from a mean of 186/microliters to 21/microliters. 152 patients have been followed for at least a year after DFMO treatment, and only 13 (9%) have relapsed. Treatment failures were more common in children less than 12 years, among patients treated with oral DFMO only, and among patients who received DFMO as the initial treatment of their recently diagnosed trypanosomiasis. Toxicity was acceptable. Only 4 patients died during or shortly after treatment. Bone marrow suppression resulting in anaemia (43%) or leucopenia (53%) was common but bore little consequence. This open trial shows that DFMO is as active as and possibly less toxic than melarsoprol. For economic and logistic reasons DFMO may not be the first-choice therapy in rural Africa but for the vast majority of patients who relapse after melarsoprol DFMO will be curative.

Association between HIV-2 infection and genital ulcer diseases among male sexually transmitted disease patients in The Gambia

OBJECTIVE

To investigate whether genital ulcer diseases are cofactors which enhance the transmission of HIV-2 in West Africa.

DESIGN

A cross-sectional study of 435 men presenting with a sexually transmitted disease (STD).

SETTING

The outpatient clinic of the Medical Research Council Laboratories, a primary care facility in Fajara, a suburb of Banjul, the capital city of The Gambia (West Africa).

PATIENTS, PARTICIPANTS

Six hundred and twenty-four men presenting with a genital complaint, of whom 443 had an STD. Eight of the men with an STD were excluded from further analysis because they were HIV-1-infected (five patients) or had indeterminate Western blot patterns (three patients). The remaining 21 HIV-2-infected and 414 seronegative men constituted our study-group.

MAIN OUTCOME MEASURES

Participants were questioned about previous STD and behavioural and demographic characteristics. A physical examination was performed and serum collected for measurement of antibodies against Haemophilus ducreyi and Treponema pallidum.

RESULTS

HIV-2-infected men were more likely than HIV-seronegative participants to have previously had a genital ulcer [odds ratio (OR), 3.00; 95% confidence interval (Cl), 1.18-7.60] and to have antibodies against T. pallidum (OR, 5.95; 95% Cl, 2.10-16.91), or H. ducreyi (OR, 4.59; 95% Cl, 1.71-12.33). Circumcised patients with residual foreskin were more likely to be HIV-2 infected than patients with complete circumcision. HIV-2-seropositive patients were six times more likely to have generalized lymphadenopathy than their seronegative counterparts.

CONCLUSIONS

Our data suggest that genital ulcerative diseases, such as syphilis and chancroid, are probably cofactors that increase the transmission of HIV-2 in West Africa, and that HIV-2 infection frequently results in generalized lymphadenopathy.

High-dose nifurtimox for arseno-resistant Trypanosoma brucei gambiense sleeping sickness: an open trial in central Zaire

Thirty patients with arseno-resistant Trypanosoma brucei gambiense sleeping sickness were treated with high-dose nifurtimox (30 mg/kg/d for 30 d). During treatment, the cerebrospinal fluid (CSF) white blood cell (WBC) count decreased in all patients except one (mean CSF WBC count before nifurtimox: 117/mm3; after nifurtimox: 25/mm3), and trypanosomes disappeared from the CSF of all 9 patients in whom parasites had been demonstrated before nifurtimox. Among 25 patients seen at least once after treatment, 9 (36%) have relapsed so far. High-dose nifurtimox was significantly toxic: one patient died during treatment and 8 others developed adverse neurological effects. High-dose nifurtimox seems more effective than the previously used regimen (15 mg/kg/d for 60 d), but at the expense of significant toxicity.